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Publication numberUS3926154 A
Publication typeGrant
Publication dateDec 16, 1975
Filing dateMay 3, 1974
Priority dateMay 4, 1973
Also published asDE2421608A1, DE2421608C2
Publication numberUS 3926154 A, US 3926154A, US-A-3926154, US3926154 A, US3926154A
InventorsWilliams Malcolm
Original AssigneeLucas Electrical Co Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Fuel control systems
US 3926154 A
Abstract
A fuel control system for an internal combustion engine comprising sensing devices for sensing the quantities of oxygen and carbon monoxide or unburnt hydrocarbons in the engine exhaust emission, a temperature measuring device, a control device for controlling the rate of supply of fuel to the engine in accordance with at least one engine parameter and apparatus controlled by the sensing devices and by the temperature measuring device so as to modify the rate of fuel supply in accordance with the quantity of carbon monoxide or unburnt hydrocarbon in the exhaust emission when the engine temperature is below a predetermined value and in accordance with the quantity of oxygen in the exhaust emission when the engine temperature is above the predetermined temperature.
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Description  (OCR text may contain errors)

' United States Patent Williams FUEL CONTROL SYSTEMS Primary Examiner-Wendell E. Burns 75 Inventor: Malcolm William S l'h ll, E l d 1 O i u ng an Assistant E raminerRonald B. Cox [73] Ass1gnee: The Lucas Electrical Company Attorney, Agent, or Firm-Waters, Schwartz & Nissen Limited, Birmingham, England [22] Filed: May 3, 1974 [57] ABSTRACT [21] Appl. No.: 466,886 A fuel control system for an internal combustion engine comprising sensing devices for sensing the quantities of oxygen and carbon monoxide or unburnt hy- [301 Forelgn Appllc au0n Pl-mmy Data drocarbons in the engine exhaust emission, a tempera- May 1973 Umted Kmgdom 21446/73 ture measuring device, a control device for controlling the rate of supply of fuel to the engine in accordance [52] 123/32 EA; 123/139 E; 60/276 with at least one engine parameter and apparatus con- [Sl] llli. Cl. FOZB 3/00; FOZM 39/00 trolled by the Sensing devices and b the temperature [58] new of Search 123/32 139 179 measuring device so as to modify the rate of fuel sup- 123/179 G; 60/276 ply in accordance with the quantity of carbon monoxide or unburnt hydrocarbon in the exhaust emission [561 References C'ted when the engine temperature is below a predeter- UNITED STATES PATENTS mined value and in accordance with the quantity of 3,738,341 6/1973 LOOS t 1 60/276 Oxygen in the exhaust mission when the engine 3,745,768 7/1973 Zechnall 123/32 EA perature is above the predetermined temperature.

3,768,259 10/1973 Carnahan 1 60/276 3,827,237 8/1974 Linder 60 276 6 Chums, 2 Drawmg Figures THENQETTLE LE TRANSDUCER ENGINE V l I SPEED CONTROL TRANSDUCER DEV'CE ENGNE CONTROL COMPARATOR TEMPERATURE CIRCUI; 2 l

TRANSDUCER )Zl I9 I LOGIC 20 UNIT Low PASS FILTERS UNBURNT HYDROCARBON SENSOR US. Patent Dec. 16, 1975 3,926,154

THROTTLE ANGLE Q I O TRANSDUCER ENGINE CONTROL 4 SPEED E DEVICE TRANSDUCER I3 CONTROL COMPARATOR ENGINE TEMPERATURE CIRCUIp 2 I TRANSDUCER I i LOGIC 2O UN)IT LOW PASS FILTERS OXYGEN sENsoR I5 I4 UNBURNT [j HYDROCARBON sENsoR FIG.I

RELATIVE POLLUTANT AIR/FUEL RATIO FIG.2

FUEL CONTROL SYSTEMS This invention relates to fuel control systems for use with internal combustion engines and has as its object the provision of such a system in a convenient form.

The invention resides in a fuel control system for use with an internal combustion engine comprising means for sensing the quantity of oxygen within the exhaust emission of the engine, means forsensing the quantity of carbon monoxide or unburnt hydrocarbon within the exhaust emission, means for measuring the temperature of the engine, and control means for controlling the rate of supply of fuel to the engine in accordance with at least one engine parameter and means for modifying the quantity of fuel fed to the engine in accordance with the quantity of carbon monoxide or unburnt hydrocarbon within the exhaust emission when the engine temperature is below a predetermined value and in accordance with the quantity of oxygen within the exhaust emission when the engine temperature is above said predetermined value.

The invention will now be more particularly described with reference to the accompanying drawings wherein:

FIG. 1 is a block circuit diagram illustrating one embodiment of a fuel control system according to the present invention, and

FIG. 2 is a graph of the relative pollutant in the exhaust emission of an engine plotted against the air/fuel ratio of the engine.

Referring to FIG. 1, the fuel control system shown therein comprises a control device which produces an electrical output pulse on a line 11 to an injector. The length of the electrical output pulse determines the time for which the injector allows fuel to pass from a pump into the engine, and hence the rate at which fuel is fed to the internal combustion engine. The control device 10 is programmed such that the length of the electrical output pulse is dependent upon the values of two engine parameters, namely the throttle angle and the engine speed and to this end a transducer 12 is provided for feeding the signal representative of the throttle angle to the control device 10, and-a transducer 13 is provided for feeding a signal representative of the engine speed to the control device 10.

Means are also provided for modifying the length of the electrical output pulse in accordance with the nature of the exhaust emission of the internal combustion engine. Such means comprises an oxygen sensor 14 and an unburnt hydrocarbon sensor 15. The sensors 14 and 15 produce electrical signals, the amplitude of which are representative of the quantity of oxygen within the exhaust emission and the quantity of unburnt hydrocarbon within the exhaust emission respectively. These signals are fed to low pass filters 16 and 17 respectively, which serve as averaging circuits, and the output of the two low pass filters l6 and 17 are fed to a logic unit 18. A transducer 19 is provided for producing a signal representative of the engine temperature and this signal is fed on the one hand to the logic unit 18 and on the other hand to a control circuit 20. The logic unit 18 connects the output from the low pass filter 17 to a first input of a comparator 21 when the output of the transducer 19 is below a predetermined value, representing a set hot engine temperature, and connects the output of the low pass filter 16 to said first input of the comparator 21 when the output of the transducer 19 is above said predetermined value. The control device 20 produces an output which varies in accordance with the engine temperature; and which is representative of the required air/fuel ratio of the engine, and this output from the control circuit 20 is fed to a second input of the comparator 21.

Now referring to the graph shown in FIG. 2, B is a curve of unburnt hydrocarbon content of the exhaust emission plotted against air/fuel ratio, and C is a curve of oxygen content of the exhaust emission plotted against air/fuel ratio. Thus, it will be seen that when the air/fuel ratio is on the rich side of the stoichiometric line (indicated by the reference numeral 22 in FIG. 2) a measure of the unburnt hydrocarbon content in the exhaust emission will produce a signal representative of the air/fuel ratio of the engine, and when the air/fuel ratio is on the lean side of the stoichiometric line 22 then the measure of the oxygen content in the exhaust emission will produce a signal representative of the air/fuel ratio of the engine. Now in practice, the air/fuel ratio of the engine will only be on the rich side when the engine temperature is low that is to say during initial warm-up of the engine, and once the engine temperature has achieved its normal operating temperature then air/fuel ratio will be on the lean side of the stoichiometric line 22. Thus, during engine warm-up the logic unit 18 connects the unburnt hydrocarbon sensor 15 to said first input of the comparator 21 which compares the actual air/fuel ratio of the engine with the required air/fuel ratio of the engine and produces an output which is connected to the control device 10 for modifying the length of the electrical output from the device 10 and thereby adjusting the quantity of fuel fed to the engine. When the engine has reached its normal operating temperature, the logic unit 18 connects the oxygen sensor 14 to said first input of the comparator 21 and once again the electrical output pulse of the device 10 is modified in accordance with the difference between the signals of the two inputs of the comparator 21.

Finally, it is to be appreciated that instead of using an unburnt hydrocarbon sensor, a carbon monoxide sensor could be used, A being a curve of carbon monoxide content of the exhaust emission plotted against air/fuel ratio.

The invention may also be applied to fuel system in which a variable speed fuel pump continuously injects fuel into the engine air intake at a rate determined by the control system.

I claim:

1. A fuel control system for an internal combustion engine comprising means for sensing the quantity of oxygen within the exhaust emission of the engine, means for sensing the quantity of carbon monoxide or unburnt hydrocarbon within the exhaust emission, means for measuring the temperature of the engine, control means for controlling the rate of supply of fuel to the engine in accordance with at least one engine parameter, and operation means coupled to said engine temperature measuring means and to said control means for modifying the quantity of fuel fed to the engine in accordance with engine temperature and the quantity of carbon monoxide or unburnt hydrocarbon within the exhaust emission when the engine temperature is below a predetermined value and in accordance with the quantity of oxygen within the exhaust emission when the engine temperature is above said predetermined value.

2. A fuel control system as claimed in claim 1 in which said means for sensing the quantity of oxygen and said means for sensing the quantity of carbon monoxide or unburnt hydrocarbon, each comprises a sensing device which produces an electrical output signal the amplitude of which is representative of the quantity of the appropriate gas.

3. A fuel control system as claimed in claim 2 including a low pass filter for each sensing device connected to reject high frequency components in said electrical output signals.

4. A fuel control system as claimed in claim 1 wherein said operation means includes logic means coupled to said engine temperature measuring means and to said oxygen sensing means and the sensing means for carbon monoxide or unburnt hydrocarbons for passing a signal from a selected one of said sensing means depending on whether the engine temperature is above or below said predetermined value.

5. A fuel control system as claimed in claim 4 wherein said operation means further comprises a comparator connected to said logic means for receiving the signal passed thereby, and means coupled to said engine temperature measuring means and to said comparator to provide a second signal to the comparator indicative of the required air/fuel ratio at the particular engine temperature which is measured.

6. A fuel control system as claimed in claim 1 wherein said control means includes means for making the air/fuel ratio relatively rich when engine temperature is low and for making the air/fuel ratio relatively lean when engine temperature is high.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3738341 *May 1, 1972Jun 12, 1973Philips CorpDevice for controlling the air-fuel ratio {80 {11 in a combustion engine
US3745768 *Mar 30, 1972Jul 17, 1973Bosch Gmbh RobertApparatus to control the proportion of air and fuel in the air fuel mixture of internal combustion engines
US3768259 *Jul 6, 1971Oct 30, 1973Universal Oil Prod CoControl for an engine system
US3827237 *Oct 24, 1972Aug 6, 1974Bosch Gmbh RobertMethod and apparatus for removal of noxious components from the exhaust of internal combustion engines
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4062337 *Sep 12, 1975Dec 13, 1977Regie Nationale Des Usines RenaultElectro-pneumatic device for regulating the supply of air to an internal combustion engine
US4088096 *Feb 15, 1977May 9, 1978Alfa Romeo S.P.A.Internal combustion engine comprising an exhaust system provided with probes for exhaust gas analysis
US4117815 *Apr 13, 1976Oct 3, 1978Nissan Motor Company, LimitedClosed-loop mixture control system for internal combustion engine using error-corrected exhaust composition sensors
US4121548 *Jul 8, 1977Oct 24, 1978Nippon Soken, Inc.Deteriorated condition detecting apparatus for an oxygen sensor
US4121554 *Jul 5, 1977Oct 24, 1978Nippondenso Co., Ltd.Air-fuel ratio feedback control system
US4131087 *Nov 10, 1975Dec 26, 1978The Lucas Electrical Company LimitedFuel injection system for an internal combustion engine
US4132195 *Jul 1, 1977Jan 2, 1979Robert Bosch GmbhMethod and apparatus for fuel mixture control
US4150645 *Aug 19, 1977Apr 24, 1979Colt Industries Operating Corp.Circuit means and apparatus for controlling the air-fuel ratio supplied to a combustion engine
US4158347 *Feb 3, 1977Jun 19, 1979Toyota Jidosha Kogyo Kabushiki KaishaFuel supply system for use in internal combustion engine
US4167924 *Oct 3, 1977Sep 18, 1979General Motors CorporationClosed loop fuel control system having variable control authority
US4169439 *Mar 21, 1977Oct 2, 1979Colt Industries Operating Corp.Circuit means and apparatus for controlling the air-fuel ratio supplied to a combustion engine
US4170967 *Oct 19, 1978Oct 16, 1979Robert Bosch GmbhApparatus for controlling the mixture of an internal combustion engine
US4194471 *Feb 28, 1978Mar 25, 1980Robert Bosch GmbhInternal combustion engine exhaust gas monitoring system
US4197822 *Feb 14, 1977Apr 15, 1980Colt Industries Operating Corp.Circuit means and apparatus for controlling the air-fuel ratio supplied to a combustion engine
US4210114 *Jan 3, 1978Jul 1, 1980Toyota Jidosha Kogyo Kabushiki KaishaAir-fuel ratio control apparatus for an internal combustion engine
US4223651 *Feb 6, 1979Sep 23, 1980Colt Industries Operating CorpSolenoid vacuum control valve means and apparatus and system for controlling the air-fuel ratio supplied to a combustion engine
US4244340 *Apr 12, 1978Jan 13, 1981Robert Bosch GmbhMethod and apparatus for controlling fuel management for an internal combustion engine
US4271798 *Oct 27, 1978Jun 9, 1981The Bendix CorporationAlternate closed loop control system for an air-fuel ratio controller
US4362499 *Dec 29, 1980Dec 7, 1982Fisher Controls Company, Inc.Combustion control system and method
US4372155 *May 20, 1981Feb 8, 1983Ford Motor CompanyMethods of monitoring a combustion system
US4452207 *Jul 19, 1982Jun 5, 1984The Bendix CorporationFuel/air ratio control apparatus for a reciprocating aircraft engine
US4625698 *Aug 23, 1985Dec 2, 1986General Motors CorporationClosed loop air/fuel ratio controller
US5179833 *Jun 18, 1991Jan 19, 1993Honda Giken Kogyo Kabushiki KaishaSystem for detecting deterioration of a three-way catalyst of an internal combustion engine
US5311854 *Jan 25, 1993May 17, 1994Brqt CorporationTwo-cycle internal combustion engine with reduced unburned hydrocarbons in the exhaust gas
US5388561 *Mar 30, 1993Feb 14, 1995Brqt CorporationTwo-cycle internal combustion engine with reduced unburned hydrocarbons in the exhaust gas and adjustable spark gap electrodes
US5582156 *Feb 13, 1995Dec 10, 1996Brqt CorporationTwo-cycle internal combustion engine with reduced unburned hydrocarbons in the exhaust gas and adjustable spark gap electrodes
US5869743 *Feb 10, 1997Feb 9, 1999Sun Electric U.K. LimitedTo analyze exhaust gas emissions from an ic engine exhaust delivery system
US6148809 *Jan 10, 2000Nov 21, 2000Cinquegrani; Vincent J.Oxygen sensor controlled continuous flow fuel system
US20110039216 *Apr 20, 2009Feb 17, 2011Basf SeProcess for controlling the addition of an auxiliary fuel
WO1994023191A1 *Mar 25, 1994Oct 13, 1994Brqt CorpTwo-cycle engine with reduced hydrocarbon emissions
Classifications
U.S. Classification123/689, 123/691, 60/276, 123/703
International ClassificationF02D41/34, F02D41/14
Cooperative ClassificationF02D41/149, F02D41/1441
European ClassificationF02D41/14D1D, F02D41/14D9D4