US20150135685A1 - Exhaust gas cleaning system for engineering vehicle - Google Patents
Exhaust gas cleaning system for engineering vehicle Download PDFInfo
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- US20150135685A1 US20150135685A1 US14/602,553 US201514602553A US2015135685A1 US 20150135685 A1 US20150135685 A1 US 20150135685A1 US 201514602553 A US201514602553 A US 201514602553A US 2015135685 A1 US2015135685 A1 US 2015135685A1
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- temperature
- exhaust gas
- engine
- regeneration
- control
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
- F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
- F01N3/025—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust
- F01N3/0253—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust adding fuel to exhaust gases
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/2058—Electric or electro-mechanical or mechanical control devices of vehicle sub-units
- E02F9/2062—Control of propulsion units
- E02F9/2066—Control of propulsion units of the type combustion engines
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2246—Control of prime movers, e.g. depending on the hydraulic load of work tools
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02F—DREDGING; SOIL-SHIFTING
- E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
- E02F9/20—Drives; Control devices
- E02F9/22—Hydraulic or pneumatic drives
- E02F9/2278—Hydraulic circuits
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/009—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series
- F01N13/0097—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having two or more separate purifying devices arranged in series the purifying devices are arranged in a single housing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
- F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
- F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/105—General auxiliary catalysts, e.g. upstream or downstream of the main catalyst
- F01N3/106—Auxiliary oxidation catalysts
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N9/00—Electrical control of exhaust gas treating apparatus
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N9/00—Electrical control of exhaust gas treating apparatus
- F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D29/00—Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto
- F02D29/04—Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto peculiar to engines driving pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0215—Introducing corrections for particular conditions exterior to the engine in relation with elements of the transmission
- F02D41/0225—Introducing corrections for particular conditions exterior to the engine in relation with elements of the transmission in relation with the gear ratio or shift lever position
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
- F02D41/024—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus
- F02D41/0245—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus by increasing temperature of the exhaust gas leaving the engine
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
- F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
- F02D41/029—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a particulate filter
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
- F02D41/1448—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an exhaust gas pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N2900/00—Details of electrical control or of the monitoring of the exhaust gas treating apparatus
- F01N2900/06—Parameters used for exhaust control or diagnosing
- F01N2900/10—Parameters used for exhaust control or diagnosing said parameters being related to the vehicle or its components
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
- F02D41/024—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus
- F02D2041/026—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to increase temperature of the exhaust gas treating apparatus using an external load, e.g. by increasing generator load or by changing the gear ratio
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2200/00—Input parameters for engine control
- F02D2200/50—Input parameters for engine control said parameters being related to the vehicle or its components
- F02D2200/502—Neutral gear position
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/04—Introducing corrections for particular operating conditions
- F02D41/08—Introducing corrections for particular operating conditions for idling
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
- F02D41/1446—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being exhaust temperatures
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
Definitions
- the present invention relates generally to exhaust gas cleaning systems for engineering vehicles.
- the invention relates to an exhaust gas cleaning system for an engineering vehicle, which allows a filter to capture particulate matter contained in exhaust gas to clean the exhaust gas and that burns and removes the particulate matter captured by the filter for cleaning the filter.
- An engineering vehicle such as hydraulic excavator or the like has a diesel engine as its drive source mounted thereon.
- Regulations on the discharge amount of particulate matter (hereinafter, called PM) discharged from the diesel engine have yearly been tightened along with that of NOx, CO, HC, etc.
- an exhaust gas cleaning system has been known that allows a filter called a diesel particulate filter (DPF) to capture PM to reduce the amount of the PM to be discharged to the outside.
- DPF diesel particulate filter
- the filter will be increasingly clogged. This increases the exhaust pressure of the engine to induce degradation in fuel consumption.
- the PM captured by the filter is appropriately burned to remove the clogging of the filter, thereby regenerating the filter.
- the filter is normally regenerated by use of an oxidation catalyst.
- the oxidation catalyst is disposed on the upstream side of the filter or directly carried on the filter. Alternatively, the oxidation catalyst is disposed on the upstream side of the filter and is directly carried on the filter.
- the temperature of the exhaust gas has to be higher than the activating temperature of the oxidation catalyst.
- forced regeneration in which the exhaust gas temperature is increased to a set temperature (a threshold value) that is higher than the activating temperature of the oxidation catalyst and is suitable for regeneration.
- the forced regeneration includes a technique for increasing the temperature of exhaust gas by performing sub-injection (after-injection) in which fuel is injected in an expansion stroke after direct main injection into an engine, and a technique for increasing the temperature of exhaust gas by allowing a regeneration fuel injector installed in an exhaust pipe to inject fuel into the exhaust gas flowing in the exhaust pipe.
- the forced regeneration of the filter includes manual regeneration in which the regeneration is started by the operator's input and automatic regeneration in which the regeneration is automatically started.
- the manual regeneration is performed as below.
- An amount of PM deposited on a filter (a deposition amount) is first estimated.
- a warning is given to an operator to perform the manual regeneration.
- the operator operates a manual regeneration switch, and the regeneration is started.
- WO 2009/60719 discloses a technology relating to manual regeneration.
- JP-2009-79500-A discloses a technology relating to automatic regeneration.
- the manual regeneration and automatic regeneration are such that the PM deposition amount is generally obtained by detecting an anteroposterior differential pressure on a filter and carrying out an operation based on the detected value of such differential pressure.
- JP-7-166840-A proposes an exhaust gas cleaning system attached with temperature-rising assistance means.
- This exhaust gas cleaning system includes a device for detecting the neutral position of a control lever.
- a neutral detecting device detects the neutral position
- the exhaust gas cleaning system starts temperature-rising assistance.
- the neutral detecting device detects an operation position switched from the neutral position
- the exhaust gas cleaning system stops the temperature-rising assistance position.
- the temperature-rising assistance means adjusts the discharge pressure and discharge amount of a hydraulic pump to increase pump output and increases engine output, thereby increasing exhaust gas temperature.
- the temperature-rising assistance is done unnecessarily, it is likely to cause melting of the filter due to the abnormal increase in the exhaust gas temperature. Further, the unnecessary temperature-rising assistance is not preferable in view of energy saving.
- the exhaust gas cleaning system in the related art stops the temperature-rising assistance on the basis of the operating position of the control lever. Therefore, there is a problem (second) as below.
- the discharge pressure of the pump is regulated by the switching control of a pressure control valve.
- the discharge amount of the pump is regulated by the tilting control of a regulator.
- a response time until the pressure control valve and the regulator are operated after a control command was received occurs.
- the control command may be issued so that the pump discharge pressure P 2 becomes the pump discharge pressure P 1 and the pump discharge amount Q 2 becomes the pump discharge amount Q 1 . In such a case, they do not become P 1 and Q 1 immediately but the discharge pressure higher than P 1 and the discharge amount greater than Q 1 are kept for a given length of time.
- the exhaust gas cleaning system in the related art has the problem (1) relating to the unnecessary temperature-rising assistance and the problem (2) relating to the deterioration in operability in resuming work.
- an exhaust gas cleaning system for an engineering vehicle including a diesel engine, a driven body driven by power of the engine, operating means for commanding the driven body to operate, and operation stopping means for stopping the operation of the driven body.
- the system includes: a filter device disposed in an exhaust system of the engine and including a filter for capturing particulate matter contained in exhaust gas; a regeneration device adapted to increase temperature of the exhaust gas to burn and remove particulate matter deposited on the filter; a regeneration control device adapted to control the start and stop of operation of the regeneration device; and temperature-rising assistance means for assisting temperature-rising of the regeneration device.
- the regeneration control device starts the operation of the temperature-rising assistance means when the operation stopping means is operated to stop the operation of the driven body during the operation of the generation device.
- the operation stopping means When the operation stopping means is operated so as to stop the operation of the driven body, a period of time during which engine output lowers is long. If the engine output lowers so that also the exhaust gas temperature gradually lowers, there is a high possibility that the exhaust gas becomes lower than a threshold value (a set temperature suitable for regeneration). In other words, unnecessary temperature-rising assistance can be avoided by starting the temperature-rising assistance only as necessary.
- a threshold value a set temperature suitable for regeneration
- the exhaust gas cleaning system further includes an exhaust temperature detecting device adapted to detect temperature of the exhaust gas.
- the regeneration control device starts the operation of the temperature-rising assistance means when the operation stopping means is operated to stop the operation of the driven body and the exhaust temperature detecting device detects temperature lower than a threshold value during the operation of the regeneration device.
- the temperature-rising assistance is started only when the exhaust gas temperature is lower than the threshold value. Therefore, the unnecessary temperature-rising assistance can further be avoided.
- the regeneration control device stops the operation of the temperature-rising assistance means when the operation stopping means is operated to release the stop of the operation of the driven body.
- a certain amount of time occurs until the operating means is operated to drive the driven body to resume the work after the operation stopping means was operated to release the stop of the operation of the driven body to enable the operation thereof.
- Such an amount of time is longer than a response time until the operation of the assistance means is stopped after the command of stopping the temperature-rising assistance was issued.
- the operation of the assistance means is surely stopped. In this way, deterioration in operability in resuming the work can be prevented.
- the engineering vehicle includes a hydraulic pump driven by the engine, and the temperature-rising means regulates at least one of the discharge pressure and discharge amount of the hydraulic pump and applies a hydraulic load to the engine.
- the engineering vehicle includes an engine control device adapted to control the engine, and the temperature-rising assistance means commands the engine control device to bring the rotation number of the engine to a predetermined rotation number higher than an idle rotation number.
- the engine output increases and the temperature-rising assistance means can assist the temperature-rising of exhaust gas during the regeneration.
- the operation stopping means is a gate lock lever selectively operated between a first position where the operation of the driven body is enabled and a second position where the operation of the driven body is disabled.
- the operation stopping means is a parking brake operated to brake travel motion during parking of the engineering vehicle.
- the operation stopping means is a shift lever switched among a forward movement position, a neutral position and a rearward movement position.
- the operation of the driven body e.g. a front work device or a traveling system
- the operation stopping means such as the gate lock lever, the parking lever, the shift lever, etc.
- the present invention can avoid the unnecessary temperature-rising assistance and prevent the degradation in operability in resuming the work.
- FIG. 1 illustrates the entire constitution of an exhaust gas cleaning system (a first embodiment).
- FIG. 2 illustrates a hydraulic drive system mounted on a hydraulic excavator.
- FIG. 3 illustrates external appearance of the hydraulic excavator.
- FIG. 4 illustrates a functional block diagram of a controller.
- FIG. 5 is a flowchart illustrating processing contents of temperature-rising assistance control.
- FIG. 6 illustrates the relationship between the discharge pressure and discharge amount of a hydraulic pump and the output power of an engine.
- FIG. 7 illustrates exhaust gas temperature with time by way of example.
- FIG. 8 illustrates the entire constitution of the exhaust gas cleaning system (a modified example).
- FIG. 9 illustrates external appearance of a wheel loader (third example).
- FIG. 10 illustrates a functional block diagram of a controller.
- FIG. 11 is a flowchart illustrating processing contents of temperature-rising assistance control.
- FIG. 12 is a flowchart illustrating processing contents of temperature-rising assistance control.
- FIG. 1 illustrates the entire constitution of an exhaust gas cleaning system for an engineering vehicle according to the first embodiment of the invention.
- a diesel engine 1 is mounted on the engineering vehicle (e.g. a hydraulic excavator).
- the engine 1 is provided with an electronic governor 1 a which is an electronic fuel injection control unit.
- the target rotation number of the engine 1 is commanded with an engine control dial 2 and the actual rotation number of the engine 1 is detected by a rotation number detecting device 3 .
- the instruction signal of the engine control dial 2 and the detected signal of the rotation number detecting device 3 are received by a controller 4 .
- the controller 4 controls the electronic governor 1 a on the basis of the command signal (the target rotation number) and the detected signal (the actual rotation number), thereby controlling the rotation number and torque of the engine 1 .
- the hydraulic excavator is provided with a gate lock lever 5 on the left front side of a cab seat 108 .
- the gate lock lever 5 can be selectively operated between a first position A which is a lowered position to limit an entrance to the cab seat 108 and a second position B which is a raised position to open the entrance to the cab seat 108 .
- the exhaust gas cleaning system is disposed on an exhaust pipe 31 constituting part of an exhaust system of the engine 1 .
- the exhaust gas cleaning system includes: a DPF device 34 including a filter 32 collecting particulate matter contained in exhaust gas and oxidation catalyst 33 disposed on the upstream side of the filter 32 ; a position detecting device 35 detecting the operating position of the gate lock lever 5 ; and a differential pressure detecting device 36 detecting anteroposterior differential pressure (a pressure loss of the filter 32 ) between the upstream side and downstream side of the filter 32 .
- the cleaning system further includes an exhaust temperature detecting device 37 installed on the upstream side of the filter to detect the temperature of exhaust gas; a regeneration switch 38 instructing manual regeneration; and a regeneration fuel injection device 39 installed on the exhaust pipe 31 between the engine 1 and the DPF device 34 .
- the oxidation catalyst 33 and the regeneration fuel injection device 39 constitute a regeneration unit which burns and removes the PM (particulate matter) deposited on the filter 32 for regenerating the filter 32 .
- FIG. 2 illustrates the hydraulic drive system mounted on the engineering vehicle (e.g. a hydraulic excavator).
- the hydraulic drive system includes: a variable displacement main hydraulic pump 11 and a fixed displacement pilot pump 12 which are driven by the engine 1 ; a plurality of actuators including a hydraulic motor 13 and hydraulic cylinders 14 and 15 , the motor 13 and the cylinders 14 and 15 being driven by the hydraulic fluid discharged from the hydraulic pump 11 ; and a plurality of flow control valves including pilot-operated flow control valves 17 to 19 which control the flow (a flow rate and a direction) of the hydraulic fluid supplied from the hydraulic pump 11 to the hydraulic motor 13 and hydraulic cylinders 14 and 15 .
- the hydraulic drive system further includes a pilot relief valve 21 which regulates the pressure of the hydraulic fluid discharged from the pilot pump 12 and forms a pilot hydraulic source 20 ; a main relief valve 22 which sets the upper limit of the discharge pressure of the main hydraulic pump 11 ; a control valve 30 installed on the downstream side of a center bypass line connecting the flow control valves 17 to 19 in series.
- the hydraulic drive system further includes a solenoid selector valve 23 connected to the downstream side of the pilot hydraulic source 20 and on/off controlled depending on the opening/closing state of the gate lock lever 5 installed at the cab seat entrance of the hydraulic excavator; and remote control valves 25 , 26 and 27 .
- the remote control valves are connected to a pilot fluid passage 24 on the downstream side of the solenoid selector valve 23 and produces control pilot pressures a, b; c, d; e and f, respectively, adapted to operate the flow control valves 17 to 19 using the hydraulic pressure of the pilot hydraulic source 20 as original pressure.
- the remote control valves 25 , 26 and 27 are operated by the corresponding left and right control levers 28 and 29 installed on the left and right of the cab seat 108 .
- the control levers 28 and 29 can each be operated in a cross shape direction.
- the remote valve 25 is operated.
- the remote control valve 27 is operated.
- the remote control valve 26 is operated.
- a remote control valve not illustrated is operated.
- control lever 28 when it is operated from the neutral direction in the one direction, the remote control valve produces control pilot pressure “a” and when the control lever 28 is operated from a neutral position in the opposite direction, the remote control valve 25 produces control pilot pressure “b”.
- the control pilot pressures “a” and “b” are led via pilot lines 25 a and 25 b to the corresponding pressure-receiving portions of the flow control valve 17 , whereby the flow control valve 17 is switched from the neutral position.
- control lever 28 when it is operated in the one direction from the neutral position, the remote control valve 27 produces control pilot pressure “e”, and when the control lever 28 is operated in the opposite direction from the neutral direction, the remote control valve 27 produces control pilot pressure “f”.
- the control pilot pressures “e” and “f” are led via pilot lines 27 a and 27 b to the corresponding pressure-receiving portions of the flow control valve 19 , whereby the flow control valve 19 is switched from the neutral position.
- control pilot pressure “c” is produced
- control pilot pressure “d” is produced.
- the control pilot pressures “c” and “d” are led via pilot control lines 26 a and 26 b, respectively, to the respective pressure-receiving portions of the flow control valve 18 , whereby the flow control valve 18 is switched from the neutral position.
- control pilot pressures a to f are subjected to communication or shutoff depending on the position of the gate lock lever 5 .
- the solenoid of the solenoid selector valve 23 is energized to switch the solenoid control valve 23 from the position illustrated in the figure. In this way, the pressure of the pilot hydraulic source 20 is led to the remote control valves 25 , 26 and 27 , which makes it possible to allow the remote control valves 25 , 26 and 27 to operate the corresponding flow control valves 17 , 18 and 19 .
- the solenoid of the solenoid selector valve 23 is de-energized to switch the position illustrated in the figure, thereby blocking the communication between the pilot hydraulic source 20 and the remote control valves 25 , 26 and 27 .
- the control valve 30 is a two-position selector valve having an open position and a close position. When the solenoid is not energized, the control valve 30 is at the open position. When the solenoid is energized, the control vale 30 is switched from the open position illustrated from the close position.
- FIG. 3 illustrates external appearance of the hydraulic excavator.
- the hydraulic excavator includes a lower travel structure 100 , an upper turning body 101 , and a front work device 102 .
- the lower travel structure 100 has left and right crawler type travelling devices 103 a and 103 b which are driven by left and right travelling devices 104 a and 104 b, respectively.
- the upper turning body 101 is mounted on the lower travel structure 100 so as to be turnable by a turning motor 105 .
- the front work device 102 is mounted onto the front portion of the upper turning body 101 so as to be able to be laid and raised.
- the upper turning body 101 is provided with an engine room 106 and a cabin 107 .
- An engine 1 is disposed in the engine room 106 .
- the gate lock lever 5 ( FIG. 1 ) is installed at the entrance to the cab seat 108 in the cabin 107 .
- the control lever units (not illustrated) incorporating the corresponding remote control levers 25 , 26 and 27 are
- the front work device 102 is of an articulated structure having a boom 111 , an arm 112 and a bucket 113 .
- the boom 111 is turned vertically by the extension and contraction of a boom cylinder 114 .
- the arm 112 is turned upward and downward, and forward and rearward by the extension and contraction of an arm cylinder 115 .
- the bucket 113 is turned upward and downward, and forward and rearward by the extension and contraction of a bucket cylinder 116 .
- the hydraulic motor 13 corresponds to e.g. the turning motor 105 .
- the hydraulic cylinder 14 corresponds to e.g. the arm cylinder 115 .
- the hydraulic cylinder 15 corresponds to e.g. the boom cylinder 114 .
- the hydraulic drive device illustrated in FIG. 2 is provided with other hydraulic actuators and control valves corresponding to the traveling motors 104 a, 104 b and the bucket cylinder 116 , etc. However, their illustrations are omitted.
- FIG. 4 illustrates a functional block of the controller 4 .
- the controller 4 includes a main controller 41 and an engine controller 43 , which are connected with each other via a communication line 44 to form a vehicle-body network.
- the main controller 41 is adapted to receive the command signal of the engine control dial 2 , the detection signals of a position detecting device 35 , of a differential pressure detecting device 36 and of an exhaust temperature detecting device 37 .
- the engine controller 43 is adapted to receive the detection signal of a rotation number detecting device 3 .
- the engine controller 43 receives the command signal of the engine control dial 2 via the communication line 44 and controls the rotation number and torque of the engine 1 on the basis of the command signal and the detected signal of the rotation number detecting device 3 .
- the main controller 41 controls the vehicle body in general such as the hydraulic drive device, etc.
- the main controller 41 controls the discharge pressure and discharge amount of the hydraulic pump 11 by controlling the control valve 30 and the regulator of the hydraulic pump 11 .
- Regeneration control and temperature-rising assistance control are each one function of the main controller 41 .
- the main controller 41 receives the detected signal of the differential pressure detecting device 36 , estimates a PM deposition amount, and executes arithmetic processing on regeneration control on the basis of the estimated PM deposition amount.
- the main controller 41 then sends a control signal corresponding to the calculation result to the engine controller 43 via the communication line 44 .
- the engine controller 43 controls the electronic governor 1 a and the regeneration fuel injection device 39 (automatic regeneration control).
- the main controller 41 receives an instruction signal of the regeneration switch 38 and executes the arithmetic processing on the regeneration control (manual regeneration control).
- the main controller 41 receives the detected signals of the position detecting device 35 and of the exhaust temperature detecting device 37 and executes arithmetic processing on the temperature-rising assistance control on the basis of the detected signals.
- the main controller 41 sends the control signals corresponding to the calculation results to the control valve 30 and the regulator of the hydraulic pump 11 to control the discharge pressure and discharge amount of the hydraulic pump 11 . In this way, the load on the engine 1 driving the hydraulic pump 11 is increased to increase the exhaust gas temperature of the engine 1 .
- FIG. 5 is a flowchart illustrating the processing contents of the temperature-rising assistance control by the main controller 41 .
- the main controller 41 first determines whether or not the main controller 41 per se is executing the regeneration control (step S 10 ). When determining that the regeneration control is being done, the main controller 41 determines whether or not the gate lock lever 5 is operatively raised to the second position B on the basis of the detected signal of the position detecting device 35 . In other words, the main controller 41 determines whether or not the gate lock lever 5 is in the locked state where the control pilot pressure is blocked (step S 20 ). When determining that the gate lock lever 5 is in the locked state, the main controller 41 determines whether or not the exhaust gas temperature is lower than a threshold value (a set value suitable for regeneration) on the basis of the detected signal of the exhaust temperature detecting device 37 (step S 30 ). When determining that the exhaust gas temperature is lower than the threshold value, the main controller 41 controls the discharge pressure and discharge amount of the hydraulic pump 11 and applies a hydraulic load to the engine 1 , thus starting the temperature-rising assistance (step S 40 ).
- a threshold value a set value suitable for regeneration
- step S 10 the main controller 41 may determine that it does not exercise the regeneration control.
- step S 20 the gate lock lever 5 may not be in the locked state (is at the first position A).
- step S 30 the exhaust gas temperature may not be lower than the threshold value (the temperature suitable for the regeneration). In any of such cases, the processing is returned to the procedure immediately after the start and the procedures of steps S 10 , S 20 and S 30 are repeated.
- FIG. 6 illustrates the relationship between the discharge pressure and discharge amount of the hydraulic pump 11 and the output power of the engine 1 .
- the discharge pressure and discharge amount of the hydraulic pump 11 are controlled to pump discharge pressure P 1 and pump discharge amount Q 1 , respectively, in view of energy saving to provide minimum engine output PS 1 .
- the discharge pressure and discharge amount of the hydraulic pump 11 are controlled to pump discharge pressure P 2 (>P 1 ) and pump discharge amount Q 2 (>Q 1 ), respectively.
- the engine 1 is allowed to have engine output PS 2 for driving the hydraulic pump 11 , that is, the load on the engine 1 is increased, thereby increasing the exhaust gas temperature of the engine 1 .
- step S 60 determination is made as to whether or not at least one of the determination in step 10 (condition 1 ), the determination in step 20 (condition 2 ) and the determination in step 30 is negative (at least one of the conditions 1 to 3 is not satisfied) (step 50 ).
- the temperature-rising assistance is stopped (step S 60 ).
- the stop of the temperature-rising assistance in step S 60 is carried out by controlling the pump discharge pressure and pump flow rate to the pump discharge pressure P 1 and pump discharge amount Q 1 , respectively, to provide the minimum engine output PS 1 .
- the load on the engine 1 is reduced to lower the exhaust gas temperature of the engine 1 .
- step S 50 When it is determined that all of conditions 1 to 3 is affirmative (all of the conditions 1 to 3 is satisfied. In other word, none of the conditions 1 to 3 is negative.) in step S 50 , the procedure of step 50 is repeated to continue the temperature-rising assistance.
- FIG. 7 illustrates an example in exhaust gas temperature with time for assisting understanding.
- exhaust gas temperature immediately after work or during work is higher than the activating temperature of the oxidation catalyst 33 .
- the regeneration fuel injection device 39 is controlled to inject fuel into the exhaust pipe 31 , unburned fuel is supplied to and oxidized by the oxidation catalyst 33 to provide reaction heat.
- reaction heat further increases the exhaust gas temperature to burn and remove the PM deposited on the filter 32 .
- the exhaust gas temperature detected by the exhaust temperature detecting device 37 is equal to or higher than a threshold value. Therefore, the temperature-rising assistance is not performed (step S 10 ⁇ S 20 ⁇ S 30 ⁇ S 10 ) (the state 1 in FIG. 7 ).
- the gate lock lever 5 is usually in the locked state.
- the discharge pressure and discharge amount of the hydraulic pump are controlled to the pump discharge pressure P 1 and the pump discharge amount Q 1 , respectively, in view of energy saving to provide the minimum engine output PS 1 . If the engine output is lowered, also the exhaust gas temperature lowers gradually and becomes lower than the threshold value. In this case, even if the forced regeneration is performed, there is a possibility that the exhaust gas temperature may not sufficiently be increased (state 2 in FIG. 7 ).
- step S 10 when the exhaust gas temperature detected by the exhaust gas temperature device 37 is lower than the threshold value, the temperature-rising assistance is started (step S 10 ⁇ S 20 ⁇ S 30 ⁇ S 40 ).
- the discharge pressure and discharge amount of the hydraulic pump are controlled to the pump discharge pressure P 2 and the pump discharge amount Q 2 , respectively, to provide engine output PS 2 , which increases exhaust gas temperature (state 3 in FIG. 7 ).
- Step S 40 After the start of the temperature-rinsing assistance, when the exhaust gas temperature is equal to or higher than the threshold value by the temperature-rising assistance or when the automatic regeneration is finished by burning and removing the PM, the temperature-rising assistance is stopped (Step S 40 ⁇ S 50 ⁇ S 60 ).
- Step S 40 ⁇ S 50 ⁇ S 60 state 4 in FIG. 7 ).
- the exhaust gas cleaning system in the related art starts the temperature-rising assistance on the basis of the neutral position of each of the control levers 28 and 29 .
- the control levers 28 and 29 are made neutral, the engine output is lowered.
- the control levers 28 and 29 are operated again to resume the work, the engine work is increased again so that it is not likely that the exhaust gas temperature becomes lower than the threshold value.
- the period of time during which the engine output is lowered is short, it is not necessary to perform the temperature-rising assistance.
- the temperature-rising assistance is performed needlessly, there is a possibility that the filter is damaged by melting due to abnormally increased temperature. In addition, such needless temperature-rising assistance is not preferable also in view of energy saving.
- the exhaust gas cleaning system starts the temperature-rising assistance on the basis of the operating position (the second position B) of the gate lock lever 5 .
- the operator When operatively raising the gate lock lever 5 to the second position B, the operator often gets away from the hydraulic excavator for a rest. Therefore, the period of time during which the engine output is lowered is long. If the engine output is lowered, also the exhaust gas temperature gradually lowers and is more likely to become lower than the threshold value. In short, the exhaust gas cleaning system according to the present embodiment starts the temperature-rising assistance only when required. Thus, the unnecessary temperature-rising assistance can be avoided.
- the exhaust gas cleaning system is provided with the exhaust temperature detecting device 37 .
- the temperature-rising assistance is not performed.
- the unnecessary temperature-rising assistance can further be avoided.
- the exhaust gas cleaning system in the related art has the following same operation with the exhaust gas cleaning system according to the present embodiment.
- Both the systems control the discharge pressure and discharge amount of the hydraulic pump 11 and increase the engine output PS 1 (the pump discharge pressure P 1 and the pump discharge amount Q 1 ) to the engine output PS 2 (the pump discharge pressure P 2 and the pump discharge amount Q 2 ).
- the systems start the temperature-rising assistance and return the engine output PS 2 to the engine output PS 1 (the pump discharge pressure P 1 and the pump discharge amount Q 1 ) and stop the temperature-rising assistance.
- the discharge pressure of the pump 11 is regulated by the switching control of the control valve 30 .
- the discharge amount of the pump 11 is regulated by the tilting control of the regulator. Response time occurs until the control valve 30 and the regulator of the pump 11 are operated after a control command was inputted. In other words, even if the control order is issued so that P 2 and Q 2 become P 1 and Q 1 , respectively, P 2 and Q 2 do not immediately become P 1 and Q 1 , respectively. Therefore, discharge pressure higher than P 1 and a discharge amount greater than Q 1 are kept for a given length of time.
- the exhaust gas cleaning system in the related art commands the stop of the temperature-rising assistance on the basis of the operating positions of the control levers 28 and 29 . There is no time until the work is resumed by the control levers 28 and 29 after the temperature-rising assistance was stopped by the control levers 28 and 29 . Therefore, if the work is resumed in this state, operability is likely to deteriorate.
- the exhaust gas cleaning system in the present embodiment commands the stop of the temperature-rising assistance on the basis of the operating position (the first position A) of the gate lock lever 5 .
- An interval of time from the command of stopping the temperature-rising assistance to the resuming of the work by the operative levers 28 and 29 i.e., an interval of time until the operator operates the control levers 28 and 29 after the operator operatively pulls down the gate lock lever 5 to enable the operation of the hydraulic excavator, is longer than the response time of the control valve 30 and of the regulator of the pump 11 . Therefore, the engine output is returned to the engine output PS 1 (the pump discharge pressure P 1 , pump discharge amount Q 1 ) at the time of resuming the work.
- PS 1 the pump discharge pressure P 1 , pump discharge amount Q 1
- the description is given on the premise of the automatic regeneration control.
- the temperature-rising assistance may be done during manual regeneration control.
- the manual regeneration control is started based on the command of a regeneration switch 38 .
- the automatic regeneration is stated when the PM deposition amount estimated by the differential pressure detecting device 36 reaches the accumulation limit value and is ended when the PM is burned and removed so that the estimated PM deposition amount becomes equal to or less than the accumulation permissible value.
- the automatic regeneration may be started after a predetermined time elapses and may be ended after a predetermined time elapses.
- the PM deposition amount is obtained by detecting the anteroposterior differential pressure on the filter by the differential pressure detecting device 36 and by performing a calculation based on the detected value of the differential pressure.
- the PM deposition amount may be obtained as below.
- the engine 1 is provided with an air-quantity detecting device 51 which detects a quantity of air flowing into the engine and with a boost pressure detecting device 52 which detects the pressure of air flowing into the engine. The quantity and pressure of the air flowing into the engine are detected by such devices and a calculation is performed based on the detected values.
- FIG. 8 illustrates the entire constitution of the exhaust gas cleaning system for an engineering vehicle according to this modified example.
- the control valve 30 and the regulator of the hydraulic pump 11 directly receive the command signals outputted from the controller 4 and are controlled based on the command signals.
- Solenoid valves are installed.
- the controller 4 sends command signals to these solenoid valves.
- the solenoid valves are each switched based on the command signals and produce control pilot pressure taking the hydraulic pressure of the pilot hydraulic source 20 as source pressure.
- the control valve 30 and the regulator of the hydraulic pump 11 are each controlled based this control pilot pressure.
- control valve 30 the regulator of the pump 11 and one function of the main controller 41 controlling these constitute the temperature-rising assistance means as below.
- the discharge pressure and discharge amount of the hydraulic pump 11 are adjusted and the hydraulic load is applied to the engine 1 to assist temperature-rising during regeneration.
- the temperature-rising assistance means is not limited to this.
- the constitution of a second embodiment is the same as that of the first embodiment; therefore, its illustration is omitted.
- the second embodiment is different from the first embodiment in the details of the start (S 40 ) and stop (S 60 ) of the temperature-rising assistance in the temperature-rising assistance control (see FIG. 5 ) of the main controller 41 .
- the start of the temperature-rising assistance in step S 40 is done as below for example.
- the gate lock lever 5 is in the locked state.
- the engine controller 43 controls the rotation number of the engine 1 to the idle rotation number NO (low rotation number) in view of energy saving (automatic idle control).
- the idle rotation number NO low rotation number
- temperature-rising assistance is performed.
- the main controller 41 switches the target rotation number of the engine 1 from the target rotation number (the idle rotation number NO) directed by the engine control dial 2 to a predetermined rotation number N 1 .
- the main controller 41 sends the target rotation number (the rotation number N 1 ) to the engine controller 43 via the communication line 44 .
- the engine controller 43 exercises feedback control on a fuel injection amount of the electronic governor 1 a on the basis of the target rotation number (the rotation number N 1 ) and the actual rotation number of the engine 1 detected by the rotation number detecting device 3 so that the rotation number of the engine 1 may become the first rotation number N 1 .
- the rotation number N 1 is one suitable for the regeneration control that can raise the temperature of the exhaust gas at that time to temperature higher than the activating temperature of the oxidation catalyst 33 .
- the rotation number N 1 is a middle-speed rotation number, e.g., approximately 1800 rpm.
- the stop of the temperature-rising assistance in step S 60 is done by controlling the rotation number of the engine 1 to the idle rotation number NO (the low-speed rotation number).
- the load on the engine 1 is reduced to lower the exhaust gas temperature of the engine 1 .
- present embodiment configured as described above can produce the effects (a), (b) and (c) of the first embodiment.
- the engineering vehicle is the hydraulic excavator.
- the gate lock lever 5 constitutes operation stopping means for disabling the operation of the front work device 102 of the hydraulic excavator to stop the operation.
- the operation stopping means for the engineering vehicle is not limited to this.
- a third embodiment is described with reference to FIGS. 9 to 12 .
- the present embodiment is such that the present invention is applied to a wheel loader.
- FIG. 9 illustrates the external appearance of the wheel loader which is an engineering vehicle according to the present embodiment.
- the wheel loader 200 includes a vehicle-body front portion 201 and a vehicle-body rear portion 202 which are turnably pin-joined to each other and which constitute a vehicle body.
- a front work device 204 is installed on the vehicle-body front portion 201 .
- a cab seat 206 is installed on the vehicle-body rear portion 202 .
- the cab seat 206 is provided with operation means such as a control lever device 207 , a steering wheel 208 and the like.
- the vehicle-body front portion 201 and the vehicle-body rear portion 202 are provided with front wheels 235 and rear wheels 236 , respectively.
- an engine 1 , a hydraulic pump 11 , a controller 4 and other devices are mounted on the vehicle-body rear portion 202 .
- the front wheels 235 and the rear wheels 236 are connected to an output shaft of the engine 1 via a torque converter and a transmission not illustrated to constitute a traveling system (not illustrated).
- an accelerator pedal 61 depresses an accelerator pedal 61 (described later)
- the rotation number and torque of the engine 1 are increased.
- Such power is transmitted to the front wheels 235 and rear wheels 236 via the torque converter and the transmission to provide travel motion.
- a steering cylinder 203 is installed between the vehicle-body front portion 201 and the vehicle-body rear portion 202 .
- the steering wheel 208 is operated to actuate the steering cylinder 203 to change the direction of the vehicle-body front portion 201 (the traveling direction of the vehicle body) with respect to the vehicle-body rear portion 202 .
- the wheel loader further includes operating means such as an accelerator pedal 61 which outputs command signals for controlling the rotation number and torque of the engine 1 and traveling speed; parking braking means such as a parking brake 62 ; and a shift lever 63 selectively switched among a forward movement position F, a neutral position N and a rearward movement position R.
- operating means such as an accelerator pedal 61 which outputs command signals for controlling the rotation number and torque of the engine 1 and traveling speed
- parking braking means such as a parking brake 62
- a shift lever 63 selectively switched among a forward movement position F, a neutral position N and a rearward movement position R.
- FIG. 10 illustrates a functional block of a controller 4 .
- a command signal of the accelerator pedal 61 is received by a main controller 41 of the controller 4 .
- the main controller 41 calculates the target rotation number of the engine 1 on the basis of the command signal.
- the main controller 41 sends a control signal corresponding to the calculation result to an engine controller 43 via a communication line 44 .
- the engine controller 43 controls an electronic governor 1 a on the basis of the target rotation number and the detected signal (the actual rotation number) of the rotation number detecting device 3 to control the rotation number and torque of the engine 1 .
- the output shaft of the engine 1 is connected to a traveling system.
- the engine controller 43 controls the rotation number and torque of the engine 1 to control traveling speed.
- temperature-rising assistance for example, if temperature-rising assistance is started based on a non-operation state of the accelerator pedal 61 , a problem associated with unnecessary temperature-rising assistance occurs. If the temperature-rising assistance is stopped based on the operation state of the accelerator pedal 61 , a problem associated with deterioration in the operability in resuming traveling occurs.
- the parking brake 62 is provided with a parking brake operating position detecting device 66 which detects the operating position thereof.
- a main controller 41 receives a detected signal of the parking brake operating position detection device 66 .
- the main controller 41 exercises braking control on the wheel loader on the basis of its command signal.
- the parking brake 62 disables the traveling of the wheel loader to stop its operation.
- the shift lever 63 is provided with a shift lever operating position detecting device 67 which detects the operating position thereof. Also the detected signal of the shift lever operating position detecting device 67 is received by the main controller 41 .
- the main controller 41 exercises switching control on switching among forward movement, neutral and rearward movement on the basis of its command signal. When being operated to be at a neutral position N, the shift lever 63 disables the traveling of the wheel loader to stop its operation.
- the parking brake 62 and the shift lever 63 each constitute operation stopping means.
- FIG. 11 and FIG. 12 are flowchart illustrating processing contents of temperature-rising assistance control by the main controller 41 in the present embodiment.
- the flowchart of FIG. 11 is different from that of FIG. 5 in that a determination relating to the operating position of the parking brake 62 is made in the processing of step S 20 and of step S 50 .
- the flowchart of FIG. 12 is different from that of FIG. 5 in that a determination relating to the operating position of the shift lever 63 is made in the processing of step S 20 and of step S 50 .
- step S 10 after it was determined to be under regeneration control in step S 10 , a determination is made as to whether or not the parking brake 62 is operated to be at the braking position on the basis of the detected signal of the parking brake operating position detecting means 66 (S 20 ).
- the temperature-rising assistance is started in step S 40 .
- condition 1 the parking bake 62 being at the braking position
- condition 3 the temperature-rising assistance is stopped in step S 60 .
- step S 20 a determination is made as to whether or not the shift lever 63 is operated to be at the neutral position N on the basis of the detected signal of the shift lever operating position detecting device 67 (step S 20 ).
- the temperature-rising assistance is started in step S 40 .
- condition 1 the shift lever 63 being at the neutral position
- condition 3 the temperature-rising assistance is stopped in step S 60 .
- the embodiment configured as described above can produce the same effects as the effects (a), (b) and (c) of the first embodiment.
- the exhaust gas cleaning system according to the present embodiment starts the temperature-rising assistance on the basis of the braking position of the parking brake 62 or the neutral position N of the shift lever 63 .
- the operator intends to allow the wheel loader not to travel.
- the period of time during which the engine output lowers becomes long.
- exhaust gas temperature gradually lowers and is likely to become lower the threshold value. That is to say, the exhaust gas cleaning system according to the present embodiment starts the temperature-rising assistance only when necessary. Thus, unnecessary temperature-rising assistance can be avoided.
- the exhaust gas purifying system commands the stop of the temperature-rising assistance on the basis of the braking-releasing position of the parking brake 62 or the forward movement position F or rearward movement position R of the shift lever 63 .
- An interval of time until the resuming of the travel by the accelerator pedal 61 after the command of stopping the temperature-rising assistance by the parking brake 62 or by the shift lever 63 is longer than the response time of the control valve 30 or of the regulator of the pump 11 .
- the engine output is returned to the engine output PS 1 (the pump discharge pressure P 1 and the pump discharge amount Q 1 ).
- the degradation in operability in resuming the traveling can be prevented.
Abstract
An exhaust gas cleaning system is provided in an engineering vehicle such as a hydraulic excavator. During automatic regeneration, when a gate lock lever 5 is in a locked state and work is not performed, the exhaust gas temperature detected by the exhaust temperature detecting device 37 may be lower than the threshold value, so temperature-rising assistance is started as follows. The minimum engine output PS1 (pump discharge pressure P1 and pump discharge amount Q1) is brought to engine output PS2 (pump discharge pressure P2 and pump discharge amount Q2). In this way, a hydraulic load is applied to an engine to thereby increase exhaust gas temperature. When the work is resumed during the regeneration, an operator pulls down the gate lock lever to the first position A, and the engine output is returned to PS1. Thus, the temperature-rising assistance is stopped, however the automatic regeneration is continued.
Description
- This application is a continuation of U.S. patent application Ser. No. 13/171,663, filed Jun. 29, 2011, which claims priority to Japanese patent application No. 2010-190215, filed Aug. 27, 2010. The entire contents of these applications are incorporated by reference herein.
- 1. Field of the Invention
- The present invention relates generally to exhaust gas cleaning systems for engineering vehicles. In particular, the invention relates to an exhaust gas cleaning system for an engineering vehicle, which allows a filter to capture particulate matter contained in exhaust gas to clean the exhaust gas and that burns and removes the particulate matter captured by the filter for cleaning the filter.
- 2. Description of the Related Art
- An engineering vehicle such as hydraulic excavator or the like has a diesel engine as its drive source mounted thereon. Regulations on the discharge amount of particulate matter (hereinafter, called PM) discharged from the diesel engine have yearly been tightened along with that of NOx, CO, HC, etc. To keep up with such regulations, an exhaust gas cleaning system has been known that allows a filter called a diesel particulate filter (DPF) to capture PM to reduce the amount of the PM to be discharged to the outside. As the amount of PM captured by the filter progressively increases during the use of such a discharge gas cleaning system, the filter will be increasingly clogged. This increases the exhaust pressure of the engine to induce degradation in fuel consumption. The PM captured by the filter is appropriately burned to remove the clogging of the filter, thereby regenerating the filter.
- The filter is normally regenerated by use of an oxidation catalyst. The oxidation catalyst is disposed on the upstream side of the filter or directly carried on the filter. Alternatively, the oxidation catalyst is disposed on the upstream side of the filter and is directly carried on the filter. In any of such cases, to activate the oxidation catalyst, the temperature of the exhaust gas has to be higher than the activating temperature of the oxidation catalyst. For this reason, there is a technology called forced regeneration in which the exhaust gas temperature is increased to a set temperature (a threshold value) that is higher than the activating temperature of the oxidation catalyst and is suitable for regeneration. The forced regeneration includes a technique for increasing the temperature of exhaust gas by performing sub-injection (after-injection) in which fuel is injected in an expansion stroke after direct main injection into an engine, and a technique for increasing the temperature of exhaust gas by allowing a regeneration fuel injector installed in an exhaust pipe to inject fuel into the exhaust gas flowing in the exhaust pipe.
- The forced regeneration of the filter includes manual regeneration in which the regeneration is started by the operator's input and automatic regeneration in which the regeneration is automatically started. The manual regeneration is performed as below. An amount of PM deposited on a filter (a deposition amount) is first estimated. When the PM deposition amount reaches a PM deposition limit amount, a warning is given to an operator to perform the manual regeneration. Then, the operator operates a manual regeneration switch, and the regeneration is started. WO 2009/60719 discloses a technology relating to manual regeneration. On the other hand, when the PM deposition amount reaches an accumulation limit value or when a predetermined time elapses, the automatic regeneration is performed. JP-2009-79500-A discloses a technology relating to automatic regeneration. The manual regeneration and automatic regeneration are such that the PM deposition amount is generally obtained by detecting an anteroposterior differential pressure on a filter and carrying out an operation based on the detected value of such differential pressure.
- Incidentally, there is a close relationship between engine output and exhaust gas temperature. For example, if the engine output lowers, the exhaust gas temperature lowers. When the exhaust gas temperature per se is low, even if forced regeneration is performed, satisfactory regeneration is not likely to be performed because of insufficiently increased temperature. To address such a problem, JP-7-166840-A proposes an exhaust gas cleaning system attached with temperature-rising assistance means.
- This exhaust gas cleaning system includes a device for detecting the neutral position of a control lever. When such a neutral detecting device detects the neutral position, the exhaust gas cleaning system starts temperature-rising assistance. When the neutral detecting device detects an operation position switched from the neutral position, the exhaust gas cleaning system stops the temperature-rising assistance position. The temperature-rising assistance means adjusts the discharge pressure and discharge amount of a hydraulic pump to increase pump output and increases engine output, thereby increasing exhaust gas temperature.
- As described above, the exhaust gas cleaning system in the related art starts the temperature-rising assistance on the basis of the neutral position of the control lever. Therefore, there is a problem (first) as below.
- For example, when a hydraulic excavator allows a front work device to work via a control lever, its engine output is increased and also exhaust gas temperature is increased accordingly. On the other hand, when the control lever is made neutral, the engine output immediately lowers while the exhaust gas temperature does not lower immediately. The exhaust gas temperature gradually lowers. When the control lever is operated again to resume the work, the engine output is increased and also the exhaust gas temperature is again increased. In other words, whenever the control lever is temporarily made neutral during the work, the temperature-rising assistance is not necessarily always performed.
- If the temperature-rising assistance is done unnecessarily, it is likely to cause melting of the filter due to the abnormal increase in the exhaust gas temperature. Further, the unnecessary temperature-rising assistance is not preferable in view of energy saving.
- The exhaust gas cleaning system in the related art stops the temperature-rising assistance on the basis of the operating position of the control lever. Therefore, there is a problem (second) as below.
- When the control lever is made neutral during the normal time, the engine becomes idle. Therefore, the engine output is brought to engine output PSmin (pump discharge pressure P1 and pump discharge amount Q1). When the control lever is made neutral during regeneration, to perform the temperature-rising assistance the engine output is brought to engine output PSmax (pump discharge pressure P2(>P1) and pump discharge amount Q2(>Q1)). Then, when the control lever is switched from the neutral position to the operating position, the engine output is regulated to the pump discharge pressure P1 and the pump discharge amount Q1, i.e., to the engine output PSmin. In this way, the temperature-rising assistance is stopped.
- In this case, the discharge pressure of the pump is regulated by the switching control of a pressure control valve. In addition, the discharge amount of the pump is regulated by the tilting control of a regulator. A response time until the pressure control valve and the regulator are operated after a control command was received occurs. Specifically, the control command may be issued so that the pump discharge pressure P2 becomes the pump discharge pressure P1 and the pump discharge amount Q2 becomes the pump discharge amount Q1. In such a case, they do not become P1 and Q1 immediately but the discharge pressure higher than P1 and the discharge amount greater than Q1 are kept for a given length of time.
- In the state where the temperature-rising assistance is not completely stopped, if slight operation work is intended to be done via a control lever, a front work device is likely to be more driven than operator's intention. Thus, operability is impaired. Further, if the work is done by the front work device, an excessive load is suddenly applied to the engine to cause abrupt lowering in the rotation number of the engine (lag-down), which significantly impairs operability.
- As described above, the exhaust gas cleaning system in the related art has the problem (1) relating to the unnecessary temperature-rising assistance and the problem (2) relating to the deterioration in operability in resuming work.
- It is an object of the present invention to provide an exhaust gas cleaning system that can avoid unnecessary temperature-rising assistance and can prevent deterioration in operability in resuming work.
- (1) According to the present invention, there is provided an exhaust gas cleaning system for an engineering vehicle including a diesel engine, a driven body driven by power of the engine, operating means for commanding the driven body to operate, and operation stopping means for stopping the operation of the driven body. The system includes: a filter device disposed in an exhaust system of the engine and including a filter for capturing particulate matter contained in exhaust gas; a regeneration device adapted to increase temperature of the exhaust gas to burn and remove particulate matter deposited on the filter; a regeneration control device adapted to control the start and stop of operation of the regeneration device; and temperature-rising assistance means for assisting temperature-rising of the regeneration device. The regeneration control device starts the operation of the temperature-rising assistance means when the operation stopping means is operated to stop the operation of the driven body during the operation of the generation device.
- When the operation stopping means is operated so as to stop the operation of the driven body, a period of time during which engine output lowers is long. If the engine output lowers so that also the exhaust gas temperature gradually lowers, there is a high possibility that the exhaust gas becomes lower than a threshold value (a set temperature suitable for regeneration). In other words, unnecessary temperature-rising assistance can be avoided by starting the temperature-rising assistance only as necessary.
- (2) Preferably, the exhaust gas cleaning system further includes an exhaust temperature detecting device adapted to detect temperature of the exhaust gas. The regeneration control device starts the operation of the temperature-rising assistance means when the operation stopping means is operated to stop the operation of the driven body and the exhaust temperature detecting device detects temperature lower than a threshold value during the operation of the regeneration device.
- In this way, the temperature-rising assistance is started only when the exhaust gas temperature is lower than the threshold value. Therefore, the unnecessary temperature-rising assistance can further be avoided.
- (3) Preferably, the regeneration control device stops the operation of the temperature-rising assistance means when the operation stopping means is operated to release the stop of the operation of the driven body.
- A certain amount of time occurs until the operating means is operated to drive the driven body to resume the work after the operation stopping means was operated to release the stop of the operation of the driven body to enable the operation thereof. Such an amount of time is longer than a response time until the operation of the assistance means is stopped after the command of stopping the temperature-rising assistance was issued. At the time of resuming the work, the operation of the assistance means is surely stopped. In this way, deterioration in operability in resuming the work can be prevented.
- (4) Preferably, the engineering vehicle includes a hydraulic pump driven by the engine, and the temperature-rising means regulates at least one of the discharge pressure and discharge amount of the hydraulic pump and applies a hydraulic load to the engine.
- (5) Preferably, the engineering vehicle includes an engine control device adapted to control the engine, and the temperature-rising assistance means commands the engine control device to bring the rotation number of the engine to a predetermined rotation number higher than an idle rotation number.
- With the constitution just above, the engine output increases and the temperature-rising assistance means can assist the temperature-rising of exhaust gas during the regeneration.
- (6) Preferably, the operation stopping means is a gate lock lever selectively operated between a first position where the operation of the driven body is enabled and a second position where the operation of the driven body is disabled.
- (7) Preferably, the operation stopping means is a parking brake operated to brake travel motion during parking of the engineering vehicle.
- (8) Preferably, the operation stopping means is a shift lever switched among a forward movement position, a neutral position and a rearward movement position.
- The operation of the driven body (e.g. a front work device or a traveling system) can be stopped by operating the operation stopping means such as the gate lock lever, the parking lever, the shift lever, etc.
- The present invention can avoid the unnecessary temperature-rising assistance and prevent the degradation in operability in resuming the work.
-
FIG. 1 illustrates the entire constitution of an exhaust gas cleaning system (a first embodiment). -
FIG. 2 illustrates a hydraulic drive system mounted on a hydraulic excavator. -
FIG. 3 illustrates external appearance of the hydraulic excavator. -
FIG. 4 illustrates a functional block diagram of a controller. -
FIG. 5 is a flowchart illustrating processing contents of temperature-rising assistance control. -
FIG. 6 illustrates the relationship between the discharge pressure and discharge amount of a hydraulic pump and the output power of an engine. -
FIG. 7 illustrates exhaust gas temperature with time by way of example. -
FIG. 8 illustrates the entire constitution of the exhaust gas cleaning system (a modified example). -
FIG. 9 illustrates external appearance of a wheel loader (third example). -
FIG. 10 illustrates a functional block diagram of a controller. -
FIG. 11 is a flowchart illustrating processing contents of temperature-rising assistance control. -
FIG. 12 is a flowchart illustrating processing contents of temperature-rising assistance control. - A first embodiment of the present invention will hereinafter be described with reference to the drawings.
-
FIG. 1 illustrates the entire constitution of an exhaust gas cleaning system for an engineering vehicle according to the first embodiment of the invention. Referring toFIG. 1 , adiesel engine 1 is mounted on the engineering vehicle (e.g. a hydraulic excavator). Theengine 1 is provided with anelectronic governor 1 a which is an electronic fuel injection control unit. The target rotation number of theengine 1 is commanded with anengine control dial 2 and the actual rotation number of theengine 1 is detected by a rotationnumber detecting device 3. The instruction signal of theengine control dial 2 and the detected signal of the rotationnumber detecting device 3 are received by acontroller 4. Thecontroller 4 controls theelectronic governor 1 a on the basis of the command signal (the target rotation number) and the detected signal (the actual rotation number), thereby controlling the rotation number and torque of theengine 1. - The hydraulic excavator is provided with a
gate lock lever 5 on the left front side of acab seat 108. Thegate lock lever 5 can be selectively operated between a first position A which is a lowered position to limit an entrance to thecab seat 108 and a second position B which is a raised position to open the entrance to thecab seat 108. - The exhaust gas cleaning system is disposed on an
exhaust pipe 31 constituting part of an exhaust system of theengine 1. The exhaust gas cleaning system includes: aDPF device 34 including afilter 32 collecting particulate matter contained in exhaust gas andoxidation catalyst 33 disposed on the upstream side of thefilter 32; aposition detecting device 35 detecting the operating position of thegate lock lever 5; and a differentialpressure detecting device 36 detecting anteroposterior differential pressure (a pressure loss of the filter 32) between the upstream side and downstream side of thefilter 32. The cleaning system further includes an exhausttemperature detecting device 37 installed on the upstream side of the filter to detect the temperature of exhaust gas; aregeneration switch 38 instructing manual regeneration; and a regenerationfuel injection device 39 installed on theexhaust pipe 31 between theengine 1 and theDPF device 34. Theoxidation catalyst 33 and the regenerationfuel injection device 39 constitute a regeneration unit which burns and removes the PM (particulate matter) deposited on thefilter 32 for regenerating thefilter 32. -
FIG. 2 illustrates the hydraulic drive system mounted on the engineering vehicle (e.g. a hydraulic excavator). The hydraulic drive system includes: a variable displacement mainhydraulic pump 11 and a fixeddisplacement pilot pump 12 which are driven by theengine 1; a plurality of actuators including ahydraulic motor 13 andhydraulic cylinders motor 13 and thecylinders hydraulic pump 11; and a plurality of flow control valves including pilot-operatedflow control valves 17 to 19 which control the flow (a flow rate and a direction) of the hydraulic fluid supplied from thehydraulic pump 11 to thehydraulic motor 13 andhydraulic cylinders pilot relief valve 21 which regulates the pressure of the hydraulic fluid discharged from thepilot pump 12 and forms a pilothydraulic source 20; amain relief valve 22 which sets the upper limit of the discharge pressure of the mainhydraulic pump 11; acontrol valve 30 installed on the downstream side of a center bypass line connecting theflow control valves 17 to 19 in series. The hydraulic drive system further includes asolenoid selector valve 23 connected to the downstream side of the pilothydraulic source 20 and on/off controlled depending on the opening/closing state of thegate lock lever 5 installed at the cab seat entrance of the hydraulic excavator; andremote control valves pilot fluid passage 24 on the downstream side of thesolenoid selector valve 23 and produces control pilot pressures a, b; c, d; e and f, respectively, adapted to operate theflow control valves 17 to 19 using the hydraulic pressure of the pilothydraulic source 20 as original pressure. - The
remote control valves cab seat 108. The control levers 28 and 29 can each be operated in a cross shape direction. When thecontrol lever 28 is operated in a one direction of the cross shape, theremote valve 25 is operated. When thecontrol lever 28 is operated in the other direction of the cross shape, theremote control valve 27 is operated. When thecontrol lever 29 is operated in a one direction of the cross shape, theremote control valve 26 is operated. When thecontrol lever 29 is operated in the other direction of the cross shape, a remote control valve not illustrated is operated. In the case where thecontrol lever 28 is operated in the one direction of the cross shape, when it is operated from the neutral direction in the one direction, the remote control valve produces control pilot pressure “a” and when thecontrol lever 28 is operated from a neutral position in the opposite direction, theremote control valve 25 produces control pilot pressure “b”. The control pilot pressures “a” and “b” are led via pilot lines 25 a and 25 b to the corresponding pressure-receiving portions of theflow control valve 17, whereby theflow control valve 17 is switched from the neutral position. - Similarly, in the case where the
control lever 28 is operated in the other direction of the cross shape, when it is operated in the one direction from the neutral position, theremote control valve 27 produces control pilot pressure “e”, and when thecontrol lever 28 is operated in the opposite direction from the neutral direction, theremote control valve 27 produces control pilot pressure “f”. The control pilot pressures “e” and “f” are led via pilot lines 27 a and 27 b to the corresponding pressure-receiving portions of theflow control valve 19, whereby theflow control valve 19 is switched from the neutral position. In the case where thecontrol lever 29 is operated in the one direction of the cross shape, when it is operated from the neutral position in the one direction, control pilot pressure “c” is produced, and when the flow control lever is operated from the neutral direction in the opposite direction, control pilot pressure “d” is produced. The control pilot pressures “c” and “d” are led via pilot control lines 26 a and 26 b, respectively, to the respective pressure-receiving portions of theflow control valve 18, whereby theflow control valve 18 is switched from the neutral position. - The control pilot pressures a to f are subjected to communication or shutoff depending on the position of the
gate lock lever 5. - When the
gate lock lever 5 is at the first position A, the solenoid of thesolenoid selector valve 23 is energized to switch thesolenoid control valve 23 from the position illustrated in the figure. In this way, the pressure of the pilothydraulic source 20 is led to theremote control valves remote control valves flow control valves gate lock lever 5 is operatively raised to the second position B, the solenoid of thesolenoid selector valve 23 is de-energized to switch the position illustrated in the figure, thereby blocking the communication between the pilothydraulic source 20 and theremote control valves remote control valves flow control valves gate lock lever 5 is operatively raised to the second position B, theremote control valves gate lock lever 5 is operatively lowered to the first position A again, the remote control levers 25, 26 and 27 are brought into an unlocked state. The switching of the position of thesolenoid valve 23 by thegate lock lever 5 is done as below. For example, a switch not illustrated in the figure is installed between the solenoid of thesolenoid selector valve 23 and the power supply. When thegate lock lever 5 is at the first position A, such a switch is turned on (closed) to energize the solenoid. When thegate lock lever 5 is operated to be at the second position B, the switch is turned off (opened) to de-energize the solenoid. - The
control valve 30 is a two-position selector valve having an open position and a close position. When the solenoid is not energized, thecontrol valve 30 is at the open position. When the solenoid is energized, thecontrol vale 30 is switched from the open position illustrated from the close position. -
FIG. 3 illustrates external appearance of the hydraulic excavator. The hydraulic excavator includes alower travel structure 100, anupper turning body 101, and afront work device 102. Thelower travel structure 100 has left and right crawlertype travelling devices devices 104 a and 104 b, respectively. Theupper turning body 101 is mounted on thelower travel structure 100 so as to be turnable by a turningmotor 105. Thefront work device 102 is mounted onto the front portion of theupper turning body 101 so as to be able to be laid and raised. Theupper turning body 101 is provided with anengine room 106 and acabin 107. Anengine 1 is disposed in theengine room 106. The gate lock lever 5 (FIG. 1 ) is installed at the entrance to thecab seat 108 in thecabin 107. The control lever units (not illustrated) incorporating the corresponding remote control levers 25, 26 and 27 are disposed on the left and right of thecab seat 108. - The
front work device 102 is of an articulated structure having aboom 111, anarm 112 and abucket 113. Theboom 111 is turned vertically by the extension and contraction of aboom cylinder 114. Thearm 112 is turned upward and downward, and forward and rearward by the extension and contraction of anarm cylinder 115. Thebucket 113 is turned upward and downward, and forward and rearward by the extension and contraction of abucket cylinder 116. - In
FIG. 2 , thehydraulic motor 13 corresponds to e.g. the turningmotor 105. Thehydraulic cylinder 14 corresponds to e.g. thearm cylinder 115. Thehydraulic cylinder 15 corresponds to e.g. theboom cylinder 114. The hydraulic drive device illustrated inFIG. 2 is provided with other hydraulic actuators and control valves corresponding to the travelingmotors 104 a, 104 b and thebucket cylinder 116, etc. However, their illustrations are omitted. -
FIG. 4 illustrates a functional block of thecontroller 4. Thecontroller 4 includes amain controller 41 and anengine controller 43, which are connected with each other via acommunication line 44 to form a vehicle-body network. Themain controller 41 is adapted to receive the command signal of theengine control dial 2, the detection signals of aposition detecting device 35, of a differentialpressure detecting device 36 and of an exhausttemperature detecting device 37. Theengine controller 43 is adapted to receive the detection signal of a rotationnumber detecting device 3. - The
engine controller 43 receives the command signal of theengine control dial 2 via thecommunication line 44 and controls the rotation number and torque of theengine 1 on the basis of the command signal and the detected signal of the rotationnumber detecting device 3. - The
main controller 41 controls the vehicle body in general such as the hydraulic drive device, etc. For example, themain controller 41 controls the discharge pressure and discharge amount of thehydraulic pump 11 by controlling thecontrol valve 30 and the regulator of thehydraulic pump 11. Regeneration control and temperature-rising assistance control are each one function of themain controller 41. - The
main controller 41 receives the detected signal of the differentialpressure detecting device 36, estimates a PM deposition amount, and executes arithmetic processing on regeneration control on the basis of the estimated PM deposition amount. Themain controller 41 then sends a control signal corresponding to the calculation result to theengine controller 43 via thecommunication line 44. In response to the control signal, theengine controller 43 controls theelectronic governor 1 a and the regeneration fuel injection device 39 (automatic regeneration control). Themain controller 41 receives an instruction signal of theregeneration switch 38 and executes the arithmetic processing on the regeneration control (manual regeneration control). - A description is given of the temperature-rising assistance control by the
main controller 41. Themain controller 41 receives the detected signals of theposition detecting device 35 and of the exhausttemperature detecting device 37 and executes arithmetic processing on the temperature-rising assistance control on the basis of the detected signals. Themain controller 41 sends the control signals corresponding to the calculation results to thecontrol valve 30 and the regulator of thehydraulic pump 11 to control the discharge pressure and discharge amount of thehydraulic pump 11. In this way, the load on theengine 1 driving thehydraulic pump 11 is increased to increase the exhaust gas temperature of theengine 1. -
FIG. 5 is a flowchart illustrating the processing contents of the temperature-rising assistance control by themain controller 41. - The
main controller 41 first determines whether or not themain controller 41 per se is executing the regeneration control (step S10). When determining that the regeneration control is being done, themain controller 41 determines whether or not thegate lock lever 5 is operatively raised to the second position B on the basis of the detected signal of theposition detecting device 35. In other words, themain controller 41 determines whether or not thegate lock lever 5 is in the locked state where the control pilot pressure is blocked (step S20). When determining that thegate lock lever 5 is in the locked state, themain controller 41 determines whether or not the exhaust gas temperature is lower than a threshold value (a set value suitable for regeneration) on the basis of the detected signal of the exhaust temperature detecting device 37 (step S30). When determining that the exhaust gas temperature is lower than the threshold value, themain controller 41 controls the discharge pressure and discharge amount of thehydraulic pump 11 and applies a hydraulic load to theengine 1, thus starting the temperature-rising assistance (step S40). - In step S10, the
main controller 41 may determine that it does not exercise the regeneration control. In step S20, thegate lock lever 5 may not be in the locked state (is at the first position A). In step S30, the exhaust gas temperature may not be lower than the threshold value (the temperature suitable for the regeneration). In any of such cases, the processing is returned to the procedure immediately after the start and the procedures of steps S10, S20 and S30 are repeated. - The start of temperature-rising assistance in step S40 is performed as below for example.
FIG. 6 illustrates the relationship between the discharge pressure and discharge amount of thehydraulic pump 11 and the output power of theengine 1. When, during normal times, thegate lock lever 5 is in the locked state and work is not done, the discharge pressure and discharge amount of thehydraulic pump 11 are controlled to pump discharge pressure P1 and pump discharge amount Q1, respectively, in view of energy saving to provide minimum engine output PS1. When the temperature-rising assistance command is issued, the discharge pressure and discharge amount of thehydraulic pump 11 are controlled to pump discharge pressure P2(>P1) and pump discharge amount Q2(>Q1), respectively. Theengine 1 is allowed to have engine output PS2 for driving thehydraulic pump 11, that is, the load on theengine 1 is increased, thereby increasing the exhaust gas temperature of theengine 1. - After the start of temperature-rising assistance, determination is made as to whether or not at least one of the determination in step 10 (condition 1), the determination in step 20 (condition 2) and the determination in
step 30 is negative (at least one of theconditions 1 to 3 is not satisfied) (step 50). When it is determined that any one is negative, the temperature-rising assistance is stopped (step S60). - The stop of the temperature-rising assistance in step S60 is carried out by controlling the pump discharge pressure and pump flow rate to the pump discharge pressure P1 and pump discharge amount Q1, respectively, to provide the minimum engine output PS1. The load on the
engine 1 is reduced to lower the exhaust gas temperature of theengine 1. - When it is determined that all of
conditions 1 to 3 is affirmative (all of theconditions 1 to 3 is satisfied. In other word, none of theconditions 1 to 3 is negative.) in step S50, the procedure ofstep 50 is repeated to continue the temperature-rising assistance. - A description is given of the operation of the exhaust gas cleaning system according to the first embodiment.
FIG. 7 illustrates an example in exhaust gas temperature with time for assisting understanding. - When the engineering vehicle (the hydraulic excavator) finishes work, an operator operatively raises the
gate lock lever 5 from the first position A to the second position B to bring it into the locked state. In this case, when the PM deposition amount reaches an accumulation limit value, automatic regeneration is started. There is also a case where, since the automatic regeneration is started during work, an operator interrupts the work and brings thegate lock lever 5 into the locked state. - In general, exhaust gas temperature immediately after work or during work is higher than the activating temperature of the
oxidation catalyst 33. When the regenerationfuel injection device 39 is controlled to inject fuel into theexhaust pipe 31, unburned fuel is supplied to and oxidized by theoxidation catalyst 33 to provide reaction heat. Such reaction heat further increases the exhaust gas temperature to burn and remove the PM deposited on thefilter 32. - In this case, the exhaust gas temperature detected by the exhaust
temperature detecting device 37 is equal to or higher than a threshold value. Therefore, the temperature-rising assistance is not performed (step S10→S20→S30→S10) (thestate 1 inFIG. 7 ). - The
gate lock lever 5 is usually in the locked state. When work is not performed, the discharge pressure and discharge amount of the hydraulic pump are controlled to the pump discharge pressure P1 and the pump discharge amount Q1, respectively, in view of energy saving to provide the minimum engine output PS1. If the engine output is lowered, also the exhaust gas temperature lowers gradually and becomes lower than the threshold value. In this case, even if the forced regeneration is performed, there is a possibility that the exhaust gas temperature may not sufficiently be increased (state 2 inFIG. 7 ). - Therefore, when the exhaust gas temperature detected by the exhaust
gas temperature device 37 is lower than the threshold value, the temperature-rising assistance is started (step S10→S20→S30→S40). The discharge pressure and discharge amount of the hydraulic pump are controlled to the pump discharge pressure P2 and the pump discharge amount Q2, respectively, to provide engine output PS2, which increases exhaust gas temperature (state 3 inFIG. 7 ). - After the start of the temperature-rinsing assistance, when the exhaust gas temperature is equal to or higher than the threshold value by the temperature-rising assistance or when the automatic regeneration is finished by burning and removing the PM, the temperature-rising assistance is stopped (Step S40→S50→S60).
- On the other hand, in a case where work is resumed during the regeneration, when the operator operatively pulls down the
gate lock lover 5 to the first position A, the temperature-rising assistance is stopped (Step S40→S50→S60) (state 4 inFIG. 7 ). - Incidentally, even if the temperature-rising assistance is stopped by operatively pulling down the
gate lock lever 5, automatic regeneration is continued. If the operator operatively pulls down thegate lock lever 5 to the first position A and resumes the work, the engine output is increased so that the exhaust gas temperature is equal to or higher than the threshold value. Thus, satisfactory regeneration is performed (state 5 inFIG. 7 ). - A description is given of the effects of the exhaust gas cleaning system according to the first embodiment.
- (a) The exhaust gas cleaning system in the related art starts the temperature-rising assistance on the basis of the neutral position of each of the control levers 28 and 29. When the control levers 28 and 29 are made neutral, the engine output is lowered. However, if the control levers 28 and 29 are operated again to resume the work, the engine work is increased again so that it is not likely that the exhaust gas temperature becomes lower than the threshold value. In other words, if the period of time during which the engine output is lowered is short, it is not necessary to perform the temperature-rising assistance. On the other hand, if the temperature-rising assistance is performed needlessly, there is a possibility that the filter is damaged by melting due to abnormally increased temperature. In addition, such needless temperature-rising assistance is not preferable also in view of energy saving.
- The exhaust gas cleaning system according to the present embodiment starts the temperature-rising assistance on the basis of the operating position (the second position B) of the
gate lock lever 5. When operatively raising thegate lock lever 5 to the second position B, the operator often gets away from the hydraulic excavator for a rest. Therefore, the period of time during which the engine output is lowered is long. If the engine output is lowered, also the exhaust gas temperature gradually lowers and is more likely to become lower than the threshold value. In short, the exhaust gas cleaning system according to the present embodiment starts the temperature-rising assistance only when required. Thus, the unnecessary temperature-rising assistance can be avoided. - (b) If the engine output is lowered, the exhaust gas temperature gradually lowers; however, it will not lower immediately. If the exhaust gas temperature is equal to or higher than the threshold value, the temperature-rising assistance is not necessary. The exhaust gas cleaning system according to the present embodiment is provided with the exhaust
temperature detecting device 37. When the exhaust gas temperature detected by the exhausttemperature detecting device 37 is equal to or higher than the threshold value, the temperature-rising assistance is not performed. Thus, the unnecessary temperature-rising assistance can further be avoided. - (c) The exhaust gas cleaning system in the related art has the following same operation with the exhaust gas cleaning system according to the present embodiment. Both the systems control the discharge pressure and discharge amount of the
hydraulic pump 11 and increase the engine output PS1 (the pump discharge pressure P1 and the pump discharge amount Q1) to the engine output PS2 (the pump discharge pressure P2 and the pump discharge amount Q2). In this way, the systems start the temperature-rising assistance and return the engine output PS2 to the engine output PS1 (the pump discharge pressure P1 and the pump discharge amount Q1) and stop the temperature-rising assistance. - In this case, the discharge pressure of the
pump 11 is regulated by the switching control of thecontrol valve 30. In addition, the discharge amount of thepump 11 is regulated by the tilting control of the regulator. Response time occurs until thecontrol valve 30 and the regulator of thepump 11 are operated after a control command was inputted. In other words, even if the control order is issued so that P2 and Q2 become P1 and Q1, respectively, P2 and Q2 do not immediately become P1 and Q1, respectively. Therefore, discharge pressure higher than P1 and a discharge amount greater than Q1 are kept for a given length of time. - The exhaust gas cleaning system in the related art commands the stop of the temperature-rising assistance on the basis of the operating positions of the control levers 28 and 29. There is no time until the work is resumed by the control levers 28 and 29 after the temperature-rising assistance was stopped by the control levers 28 and 29. Therefore, if the work is resumed in this state, operability is likely to deteriorate.
- The exhaust gas cleaning system in the present embodiment commands the stop of the temperature-rising assistance on the basis of the operating position (the first position A) of the
gate lock lever 5. An interval of time from the command of stopping the temperature-rising assistance to the resuming of the work by the operative levers 28 and 29, i.e., an interval of time until the operator operates the control levers 28 and 29 after the operator operatively pulls down thegate lock lever 5 to enable the operation of the hydraulic excavator, is longer than the response time of thecontrol valve 30 and of the regulator of thepump 11. Therefore, the engine output is returned to the engine output PS1 (the pump discharge pressure P1, pump discharge amount Q1) at the time of resuming the work. Thus, it is possible to prevent operability from deteriorating at the time of resuming the work. - The embodiment of the present invention has been described thus far. However, the present invention is not limited to this. The invention can be modified in various ways within the scope of the spirit thereof. The following recites such modified examples.
- 1. In the operation of the present embodiment, the description is given on the premise of the automatic regeneration control. However, the temperature-rising assistance may be done during manual regeneration control. The manual regeneration control is started based on the command of a
regeneration switch 38. - 2. In the operation of the present embodiment, the automatic regeneration is stated when the PM deposition amount estimated by the differential
pressure detecting device 36 reaches the accumulation limit value and is ended when the PM is burned and removed so that the estimated PM deposition amount becomes equal to or less than the accumulation permissible value. However, the automatic regeneration may be started after a predetermined time elapses and may be ended after a predetermined time elapses. - 3. In the operation of the present embodiment, the PM deposition amount is obtained by detecting the anteroposterior differential pressure on the filter by the differential
pressure detecting device 36 and by performing a calculation based on the detected value of the differential pressure. However, the PM deposition amount may be obtained as below. Theengine 1 is provided with an air-quantity detecting device 51 which detects a quantity of air flowing into the engine and with a boostpressure detecting device 52 which detects the pressure of air flowing into the engine. The quantity and pressure of the air flowing into the engine are detected by such devices and a calculation is performed based on the detected values.FIG. 8 illustrates the entire constitution of the exhaust gas cleaning system for an engineering vehicle according to this modified example. - 4. In the operation of the present embodiment, as illustrated in the functional block diagram (
FIG. 4 ) of thecontroller 4, thecontrol valve 30 and the regulator of thehydraulic pump 11 directly receive the command signals outputted from thecontroller 4 and are controlled based on the command signals. However, another constitution as below may be possible. Solenoid valves are installed. Thecontroller 4 sends command signals to these solenoid valves. The solenoid valves are each switched based on the command signals and produce control pilot pressure taking the hydraulic pressure of the pilothydraulic source 20 as source pressure. Thecontrol valve 30 and the regulator of thehydraulic pump 11 are each controlled based this control pilot pressure. - In the first embodiment, the
control valve 30, the regulator of thepump 11 and one function of themain controller 41 controlling these constitute the temperature-rising assistance means as below. The discharge pressure and discharge amount of thehydraulic pump 11 are adjusted and the hydraulic load is applied to theengine 1 to assist temperature-rising during regeneration. However, the temperature-rising assistance means is not limited to this. - The constitution of a second embodiment is the same as that of the first embodiment; therefore, its illustration is omitted. The second embodiment is different from the first embodiment in the details of the start (S40) and stop (S60) of the temperature-rising assistance in the temperature-rising assistance control (see
FIG. 5 ) of themain controller 41. - The start of the temperature-rising assistance in step S40 is done as below for example.
- During the normal time, the
gate lock lever 5 is in the locked state. When work is not done, theengine controller 43 controls the rotation number of theengine 1 to the idle rotation number NO (low rotation number) in view of energy saving (automatic idle control). During regeneration, when exhaust gas temperature is insufficient, temperature-rising assistance is performed. - The
main controller 41 switches the target rotation number of theengine 1 from the target rotation number (the idle rotation number NO) directed by theengine control dial 2 to a predetermined rotation number N1. In addition, themain controller 41 sends the target rotation number (the rotation number N1) to theengine controller 43 via thecommunication line 44. Theengine controller 43 exercises feedback control on a fuel injection amount of theelectronic governor 1 a on the basis of the target rotation number (the rotation number N1) and the actual rotation number of theengine 1 detected by the rotationnumber detecting device 3 so that the rotation number of theengine 1 may become the first rotation number N1. The rotation number N1 is one suitable for the regeneration control that can raise the temperature of the exhaust gas at that time to temperature higher than the activating temperature of theoxidation catalyst 33. For example, the rotation number N1 is a middle-speed rotation number, e.g., approximately 1800 rpm. - The stop of the temperature-rising assistance in step S60 is done by controlling the rotation number of the
engine 1 to the idle rotation number NO (the low-speed rotation number). The load on theengine 1 is reduced to lower the exhaust gas temperature of theengine 1. - Also the present embodiment configured as described above can produce the effects (a), (b) and (c) of the first embodiment.
- In the first embodiment, the engineering vehicle is the hydraulic excavator. The
gate lock lever 5 constitutes operation stopping means for disabling the operation of thefront work device 102 of the hydraulic excavator to stop the operation. However, the operation stopping means for the engineering vehicle is not limited to this. - A third embodiment is described with reference to
FIGS. 9 to 12 . The present embodiment is such that the present invention is applied to a wheel loader. -
FIG. 9 illustrates the external appearance of the wheel loader which is an engineering vehicle according to the present embodiment. InFIG. 9 , thewheel loader 200 includes a vehicle-body front portion 201 and a vehicle-bodyrear portion 202 which are turnably pin-joined to each other and which constitute a vehicle body. Afront work device 204 is installed on the vehicle-body front portion 201. Acab seat 206 is installed on the vehicle-bodyrear portion 202. Thecab seat 206 is provided with operation means such as acontrol lever device 207, asteering wheel 208 and the like. The vehicle-body front portion 201 and the vehicle-bodyrear portion 202 are provided withfront wheels 235 andrear wheels 236, respectively. In addition, anengine 1, ahydraulic pump 11, acontroller 4 and other devices are mounted on the vehicle-bodyrear portion 202. Thefront wheels 235 and therear wheels 236 are connected to an output shaft of theengine 1 via a torque converter and a transmission not illustrated to constitute a traveling system (not illustrated). When the operator depresses an accelerator pedal 61 (described later), the rotation number and torque of theengine 1 are increased. Such power is transmitted to thefront wheels 235 andrear wheels 236 via the torque converter and the transmission to provide travel motion. Asteering cylinder 203 is installed between the vehicle-body front portion 201 and the vehicle-bodyrear portion 202. Thesteering wheel 208 is operated to actuate thesteering cylinder 203 to change the direction of the vehicle-body front portion 201 (the traveling direction of the vehicle body) with respect to the vehicle-bodyrear portion 202. - The wheel loader further includes operating means such as an
accelerator pedal 61 which outputs command signals for controlling the rotation number and torque of theengine 1 and traveling speed; parking braking means such as aparking brake 62; and ashift lever 63 selectively switched among a forward movement position F, a neutral position N and a rearward movement position R. -
FIG. 10 illustrates a functional block of acontroller 4. - A command signal of the
accelerator pedal 61 is received by amain controller 41 of thecontroller 4. Themain controller 41 calculates the target rotation number of theengine 1 on the basis of the command signal. Themain controller 41 sends a control signal corresponding to the calculation result to anengine controller 43 via acommunication line 44. Theengine controller 43 controls anelectronic governor 1 a on the basis of the target rotation number and the detected signal (the actual rotation number) of the rotationnumber detecting device 3 to control the rotation number and torque of theengine 1. The output shaft of theengine 1 is connected to a traveling system. Theengine controller 43 controls the rotation number and torque of theengine 1 to control traveling speed. - In the present embodiment, for example, if temperature-rising assistance is started based on a non-operation state of the
accelerator pedal 61, a problem associated with unnecessary temperature-rising assistance occurs. If the temperature-rising assistance is stopped based on the operation state of theaccelerator pedal 61, a problem associated with deterioration in the operability in resuming traveling occurs. - The
parking brake 62 is provided with a parking brake operatingposition detecting device 66 which detects the operating position thereof. Amain controller 41 receives a detected signal of the parking brake operatingposition detection device 66. Themain controller 41 exercises braking control on the wheel loader on the basis of its command signal. When being operated to be at the braking position, theparking brake 62 disables the traveling of the wheel loader to stop its operation. - The
shift lever 63 is provided with a shift lever operatingposition detecting device 67 which detects the operating position thereof. Also the detected signal of the shift lever operatingposition detecting device 67 is received by themain controller 41. Themain controller 41 exercises switching control on switching among forward movement, neutral and rearward movement on the basis of its command signal. When being operated to be at a neutral position N, theshift lever 63 disables the traveling of the wheel loader to stop its operation. - The
parking brake 62 and theshift lever 63 each constitute operation stopping means. -
FIG. 11 andFIG. 12 are flowchart illustrating processing contents of temperature-rising assistance control by themain controller 41 in the present embodiment. The flowchart ofFIG. 11 is different from that ofFIG. 5 in that a determination relating to the operating position of theparking brake 62 is made in the processing of step S20 and of step S50. The flowchart ofFIG. 12 is different from that ofFIG. 5 in that a determination relating to the operating position of theshift lever 63 is made in the processing of step S20 and of step S50. - Specifically, in
FIG. 11 , after it was determined to be under regeneration control in step S10, a determination is made as to whether or not theparking brake 62 is operated to be at the braking position on the basis of the detected signal of the parking brake operating position detecting means 66 (S20). When it is determined that theparking brake 62 is operated to be at the braking position and it is determined that the exhaust gas temperature is lower than a threshold value in step S30, the temperature-rising assistance is started in step S40. - After the temperature-rising assistance has been started, when at least one of
condition 1, condition 2 (theparking bake 62 being at the braking position) andcondition 3 is determined as negative, the temperature-rising assistance is stopped in step S60. - In
FIG. 12 , after it was determined to be under regeneration control in step S10, a determination is made as to whether or not theshift lever 63 is operated to be at the neutral position N on the basis of the detected signal of the shift lever operating position detecting device 67 (step S20). When it is determined that theshift lever 63 is operated to be at the neutral position N and that the exhaust gas temperature is lower than a threshold value in step S30, the temperature-rising assistance is started in step S40. - After the temperature-rising assistance has been started, when at least one of
condition 1, condition 2 (theshift lever 63 being at the neutral position) andcondition 3 is determined as negative, the temperature-rising assistance is stopped in step S60. - Also the embodiment configured as described above can produce the same effects as the effects (a), (b) and (c) of the first embodiment.
- (a) The exhaust gas cleaning system according to the present embodiment starts the temperature-rising assistance on the basis of the braking position of the
parking brake 62 or the neutral position N of theshift lever 63. When operating theparking brake 62 to be at the braking position or theshift lever 63 to be at the neutral position N, the operator intends to allow the wheel loader not to travel. In this case, the period of time during which the engine output lowers becomes long. When the engine output lowers, exhaust gas temperature gradually lowers and is likely to become lower the threshold value. That is to say, the exhaust gas cleaning system according to the present embodiment starts the temperature-rising assistance only when necessary. Thus, unnecessary temperature-rising assistance can be avoided. - (b) When engine output lowers, it is gradually that the exhaust gas temperature lowers; however, it is not immediately that the exhaust gas temperature lowers. When the exhaust gas temperature is equal to or higher than a threshold value, the temperature-rising assistance is not necessary. The exhaust gas cleaning system according to the embodiment is provided with the exhaust gas
temperature detecting device 37. When the exhaust gas temperature detected by the exhausttemperature detecting device 37 is equal to or higher than the threshold value, the temperature-rising assistance is not done. This can further avoid unnecessary temperature-rising assistance. - (c) The exhaust gas purifying system according to the present embodiment commands the stop of the temperature-rising assistance on the basis of the braking-releasing position of the
parking brake 62 or the forward movement position F or rearward movement position R of theshift lever 63. An interval of time until the resuming of the travel by theaccelerator pedal 61 after the command of stopping the temperature-rising assistance by theparking brake 62 or by theshift lever 63, that is to say, an interval of time until theaccelerator 61 is operated after the operator operates theparking brake 62 or theshift lever 63 to enable the wheel loader to be traveled, is longer than the response time of thecontrol valve 30 or of the regulator of thepump 11. At the time of resuming the travel, the engine output is returned to the engine output PS1 (the pump discharge pressure P1 and the pump discharge amount Q1). Thus, the degradation in operability in resuming the traveling can be prevented.
Claims (3)
1. A hydraulic excavator comprising:
a diesel engine;
a hydraulic pump driven by the engine;
a plurality of actuators driven by a hydraulic fluid discharged from the hydraulic pump for driving a plurality of driven bodies;
a plurality of operating lever units for commanding the driven bodies to operate;
a plurality of flow control valves activated by said plurality of operating lever units for controlling flow of the hydraulic fluid supplied from the hydraulic pump to said plurality of actuators;
operation stopping means for disabling the operation of the driven bodies even if the operating lever units are operated; and
an exhaust gas cleaning system, wherein the exhaust gas cleaning system includes:
a filter device disposed in an exhaust system of the engine and including a filter for capturing particulate matter contained in exhaust gas;
a regeneration device having an oxidation catalyst and configured to supply unburned fuel to the oxidation catalyst to increase temperature of the exhaust gas thereby to burn and remove particulate matter deposited on the filter; and
a regeneration control device configured to control the start and stop of operation of the regeneration device,
wherein the operation stopping means includes a gate lock lever selectively operable between a first position to limit an entrance to a cab seat and a second position to open the entrance to the cab seat and configured such that, when the gate lock lever is located in the first position, the operation of said plurality of flow control valves by said plurality of operating lever units is enabled thereby to enable the operation of said plurality of actuators to drive said driven bodies and, when the gate lock lever is operated from the first position to the second position, the operation of said plurality of flow control valves by said plurality of operating lever units is disabled thereby to disable the operation of said plurality of actuators to drive the driven bodies,
wherein the exhaust gas cleaning system further includes temperature-rising assistance device for assisting temperature-rising of the regeneration device by increasing at least one of the discharge pressure and discharge amount of the hydraulic pump so as to apply a hydraulic load to the engine thereby to increase the temperature of the exhaust gas and oxidize the unburned fuel with the oxidation catalyst, and
wherein the regeneration control device is configured to start the operation of the temperature-rising assistance device when the gate lock lever is operated from the first position to the second position during the operation of the regeneration device.
2. The hydraulic excavator according to claim 1 ,
wherein the regeneration control device is configured to stop the operation of the temperature-rising assistance means when the gate lock lever is operated from the second position to the first position to release disabling of the driving of said plurality of actuators and release the stop of the operation of the driven bodies.
3. The hydraulic excavator according to claim 1 ,
wherein the temperature-rising assistance includes a control valve installed on a downstream side of a center bypass line connecting said plurality of control valves in series and having an open position and a closed position, and
wherein the regeneration control device is configured to apply the hydraulic load to the engine by switching the control valve from the open position to the closed position.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/602,553 US20150135685A1 (en) | 2010-08-27 | 2015-01-22 | Exhaust gas cleaning system for engineering vehicle |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2010190215A JP5548882B2 (en) | 2010-08-27 | 2010-08-27 | Exhaust gas purification system for work vehicles |
JP2010-190215 | 2010-08-27 | ||
US13/171,663 US20120047883A1 (en) | 2010-08-27 | 2011-06-29 | Exhaust gas cleaning system for engineering vehicle |
US14/602,553 US20150135685A1 (en) | 2010-08-27 | 2015-01-22 | Exhaust gas cleaning system for engineering vehicle |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/171,663 Continuation US20120047883A1 (en) | 2010-08-27 | 2011-06-29 | Exhaust gas cleaning system for engineering vehicle |
Publications (1)
Publication Number | Publication Date |
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US20150135685A1 true US20150135685A1 (en) | 2015-05-21 |
Family
ID=44508820
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/171,663 Abandoned US20120047883A1 (en) | 2010-08-27 | 2011-06-29 | Exhaust gas cleaning system for engineering vehicle |
US14/602,553 Abandoned US20150135685A1 (en) | 2010-08-27 | 2015-01-22 | Exhaust gas cleaning system for engineering vehicle |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
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US13/171,663 Abandoned US20120047883A1 (en) | 2010-08-27 | 2011-06-29 | Exhaust gas cleaning system for engineering vehicle |
Country Status (5)
Country | Link |
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US (2) | US20120047883A1 (en) |
EP (1) | EP2423481B1 (en) |
JP (1) | JP5548882B2 (en) |
KR (1) | KR101810692B1 (en) |
CN (1) | CN102383900B (en) |
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US9850793B2 (en) | 2012-12-25 | 2017-12-26 | Hino Motors, Ltd. | Automatic regeneration control device for particulate filter |
CN114458463A (en) * | 2022-01-29 | 2022-05-10 | 徐州徐工挖掘机械有限公司 | Engineering machinery emission thermal management system and method and engineering machinery |
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KR101955533B1 (en) * | 2012-10-16 | 2019-03-07 | 주식회사 두산 | Multi-step Regeneration Apparatus of DPF and Regeneration Method for the same |
JP5907284B2 (en) * | 2012-12-07 | 2016-04-26 | トヨタ自動車株式会社 | Abnormality detection device for exhaust purification system |
JP6089665B2 (en) * | 2012-12-13 | 2017-03-08 | コベルコ建機株式会社 | Hydraulic control equipment for construction machinery |
KR102271461B1 (en) * | 2013-12-24 | 2021-07-01 | 두산인프라코어 주식회사 | Diesel Particulate Filter and Control method of thereof |
US10358960B2 (en) | 2015-02-16 | 2019-07-23 | Volvo Construction Equipment Ab | Torque control system for DPF regeneration |
JP6255137B2 (en) * | 2015-03-13 | 2017-12-27 | 日立建機株式会社 | Control device for hybrid construction machine |
JP6450629B2 (en) * | 2015-04-02 | 2019-01-09 | 株式会社日立建機ティエラ | Hydraulic drive device for work machine |
KR102130188B1 (en) * | 2016-12-28 | 2020-08-05 | 주식회사 두산 | System and method of dpf regeneration of engine type forklift truck during driving of vehicle |
CN107859088B (en) * | 2017-11-24 | 2020-12-11 | 山推工程机械股份有限公司 | Hydraulic cleaning and filtering system and method for bulldozer transmission |
JP6824921B2 (en) * | 2018-03-27 | 2021-02-03 | 日立建機株式会社 | Construction machinery |
JP6950642B2 (en) * | 2018-08-01 | 2021-10-13 | 株式会社豊田自動織機 | Exhaust treatment device |
GB2598352A (en) * | 2020-08-27 | 2022-03-02 | Bamford Excavators Ltd | A control system |
CN115288829A (en) * | 2022-08-15 | 2022-11-04 | 潍柴动力股份有限公司 | Regeneration control method for Diesel Particulate Filter (DPF) of crane |
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Also Published As
Publication number | Publication date |
---|---|
JP5548882B2 (en) | 2014-07-16 |
JP2012047107A (en) | 2012-03-08 |
EP2423481B1 (en) | 2021-03-03 |
KR101810692B1 (en) | 2018-01-25 |
EP2423481A1 (en) | 2012-02-29 |
US20120047883A1 (en) | 2012-03-01 |
KR20120020071A (en) | 2012-03-07 |
CN102383900B (en) | 2015-11-25 |
CN102383900A (en) | 2012-03-21 |
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