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Publication numberUS3847130 A
Publication typeGrant
Publication dateNov 12, 1974
Filing dateAug 22, 1972
Priority dateAug 23, 1971
Publication numberUS 3847130 A, US 3847130A, US-A-3847130, US3847130 A, US3847130A
InventorsS Harada, K Majima, T Miyoshi, M Sueishi
Original AssigneeNippon Denso Co, Toyota Motor Co Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electrical fuel injection system for internal combustion engines
US 3847130 A
Abstract
An electrical fuel injection system for internal combustion engines, in which the operation of regular electromagnetic fuel injection valves is forcibly prevented so long as a starting electromagnetic fuel injection valve is in operation, whereby the engine can be started smoothly and positively without wetting the spark plug only with a readily atomizable fuel injected from the starting electromagnetic injection valve.
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United States Patent 1191 Miyoshi et al.

1451 Nov. 12, 1974 1 ELECTRICAL FUEL INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES [75] Inventors: Takeo Miyoshi, Toyota; Kazu Majima; Tetsuo Yamagata, both of Kariya; Susumu Harada, Okazaki; Motoharu Sueishi, Kariya, all of Japan [73] Assignees: Nippondenso Co., Ltd., Aichi-ken;

Toyota Jidosha Kogyo Kabushiki Kaisha, Toyota-shi, both of, Japan [22] Filed: Aug. 22, 1972 [21] Appl. No.: 282,663

[30] Foreign Application Priority Data Aug. 23. 1971 Japan 46-64293 [52] US. Cl 123/179 L, 123/32 EA, 123/179 G [51] Int. Cl... F02n 17/00, FO2b 3/00 [58] Field of Search 123/32 CA, 32AE, 179 G,-

[56] References Cited UNITED STATES PATENTS Schmid 123/32 CA- 3.534.723 10/1970 Tramontini 123/32 CA 3.614.945 10/1971 Schlagmuler 123/179 0 3,646,918 3 1972 Wagy 123/32 CA 3.680.532 8/1972 0111611. 123/179 0 3.704702 12/1972 AOIIO 123 32 CA 2 1973 Schmid 123 32 CA I FOREIGN PATENTS OR APPLICATIQNS 1,288,846 2/1969 Germany 123/1796 Primary ExaminerChar1es J. Myhre Assistant Examiner-Ronald B. Cox Attorney, Agent, or FirmCushrnan, Darby &

- Cushman [57] ABSTRACT An electrical fuel injection system for internal combustion engines, in which the operation of regular electromagnetic fuel injection valves is forcibly prevented so long as a starting electromagnetic fuel injec- 1 tion valve is in operation, whereby the engine can be started smoothly and positively without wetting the spark plug only with a readily atomizable fuel injected from the starting electromagnetic injection valve.

6 Claims, 3 Drawing Figures PATENIEDauv 12 I974 FIG. 3

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ENGINE ELECTRICAL FUEL INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a fuel injection system for internal combustion engines and more particularly to an electrical fuel injection system for a spark-ignition type internal combustion engine which employs no carburetor and in which the quantity of fuel required for the engine is electrically computed so that the electromagnetic injection valves are energized to inject fuel by pulse signals whose time width corresponds to the quantity of fuel required.

2. Description of the Prior Art In known systems of this type, in addition to the regular electromagnetic injection valves designed to inject an electrically computed quantity of fuel during normal operation of the engine, a starting electromagnetic injection valve is provided to inject a readily atomizable fuel, i.e., a fuel which is easily vaporized, to thereby ensure a good starting of the engine particularly at low temperatures of the engine.

Also the known electrical fuel injection systems generally employ a so-called warming-up enrichment method by which the quantity of fuel injected from the regular electromagnetic injection valves is increased in accordance with the temperatures of an engine until the temperature of the engine attains a predetermined value after'the starting thereof.

With the conventional electrical fuel injection systems of the type described above, however, there is a drawback in that while both the starting electromagnetic injection valve and regular electromagnetic injection valves inject the fuel upon starting the engine, un-

like the starting electromagnetic injection valve, the

regular electromagnetic injection valves place great importance on their high-speed response characteristics and are adapted to limit the spray angle of injected fuel so as to allow the injected fuel to be drawn into the cylinders without falling along the inner walls of the intake manifold. This fact has the effect of making the atomization of the injected fuel poor. Consequently, if the driver cranks over and over again owing to his lack of experience or the ignition spark is weak owing to the lowered voltage of the battery while the bad atomiza- SUMMARY OF THEINVENTION To overcome the foregoing difficulties, it is an object ofthe present invention to provide an electrical fuel injection system for. internal combustion engines in which, noting the fact that at the operating temperatures of the starting electromagnetic. injection valve, a large quantity of poorly atomizable fuel injected from the regular electromagnetic injection valves only tends to wet the spark plug and thus gives rise to an inconvenience instead of contributing to a smooth starting of like to electrically compute from these inputs the quanvide an electrical fuel injection system for internal combustion engines of the type in which the quantity of fuel required for an internal combustion engine is electrically calculated and the regular electromagnetic injection valves are energized to inject fuel by means of pulse signals whose time width corresponds to the said fuelquantity required and there is provided a starting electromagnetic injection valve designed to inject an engine starting fuel when starting the engine independent of the regular electromagnetic injectionvalves, the system comprising a start detector for detecting the start of the internal combustion engine to produce an output signal, and a circuit for receiving the output signal of the start detector to prevent the operation of the regular electromagnetic injection valves and to ener-' gize only the starting electromagnetic injection valve.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an electrical circuit diagram showing a first I embodiment of the electrical fuel injection system for an internal combustion engine according to the present invention.

FIG. 2 is an electrical circuit diagram showing an embodiment of the temperature detector and the start detector employed in the electronic computing'circuit of the system of the present invention.

FIG. 3 is an electrical circuit diagram showing a second embodiment-of the system according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1 illustrating a first embodiment of the present invention, numeral 1 designates an internal combustion engine with four cylinders; 2 an air intake manifold; 3 an air cleaner; 4 a throttle valve. Nu merals 5, 6, 7 and 8 designate regular electromagnetic injection valves adapted, when energized, to open and inject fuel and located opposite to and adjacent the air inlet valves in the respective cylinders. Numeral 9 des- .ignates a starting electromagnetic injection valve'located at a position more remote from the intake manifold 2 than the regular electromagnetic injection valves 5 to 8 and directed toward the intake manifold 2. Numeral l0 designates an electronic computing circuit for electrically detecting the number of revolutions of the engine 1, the pressure in the intake manifold 2 and'the tity of fuel required for the engine and thus produce successively at its output terminals 10a, 10b, 10c and 10d pulse signals whose time width corresponds to the computed fuel requirement of the engine. The-electronic computing circuit 10 also includes therein a temperature detector for detectingthe temperature of the engine and a start detector for detecting the starting of the engine, whereby when the temperature of the engine detected at the'start thereof is below a preset value of 20C, for example, a signal is produced at the output terminal 10 e. Numerals 11, 12, 13 and 14 designate NAND gates having one input thereof respectively connccted to the output terminals 10a, 10b, 10c and 10d of the electronic computing circuit 10. Numerals 15, 16, 17 and 18 designate inverter amplifiers wherein the outputs of the NAND gates 11, 12, 13 and 14 are inverted and amplified for application to the magnetic coils of the regular electromagnetic injection valves 5,

6, 7 and 8. Numeral 19 designates a non-inverter amplifier wherein the signal produced at the output terminal 106 of the electronic computing circuit 10 is amplified and then applied to the magnetic coil of the starting electromagneticinjection valve 9; 20 an inverter for inverting the signal produced at the output terminal 100 and then applying the inverted signal to the other input terminals of the NAND gates 11, 12, 1 3 and 14.

The temperature detector and the start detector in the electronic computing circuit 10 are constructed as shown in FIG. 2, in which numeral 21 designates the temperature detector; 22 a thermistor immersed in the cooling water of the engine 1; 23, 24 and 25, resistors; 26 an amplifier; 27 a comparator amplifier; and 28 a Zener diode for generating a reference voltage which determines a preset temperature. It is prearranged such that a signal is generated at the output terminal of the comparator amplifier 27 when the voltage representing mistor 22 is lower than the reference voltage generated by the Zener diode 28 and representing the preset temperature, while a 1 signal is generated at said output terminal when the former voltage is higher than the latter reference voltage. Numeral 29 designates a starting motor for cranking the engine 1; 30 a starter switch which is closed to operate the starting motor 29 for starting the engine 1; 31'the start detector; 32-and 33, resistors; 34 a transistor. It is prearranged such that when the starter switch 30 is open, that is, whenthe engine 1 is not being started, the transistor34 is .nonconducted producing a 1 signal at its collector, whereas when they starter switch 30 is closed, that is, when the engine 1 is being started, the transistor 34 is conducted producing a 0 signal at its collector. Numerals 35'and 36 designate diodes; 37 and 38, resistors; 39 a transisz tor whose collector constitutes the output terminal c;

40 a battery installed in the vehicle.

1 parator amplifier 27 of the temperature detector 21, so

that the transistor 39 is rendered non-conductive producing a 1 signal at its collector, i.e.,'the output terminal lOe of the electronic computing circuit 10. This 1 signal is amplified by the non-inverter amplifier 19 and his then applied to the magnetic coil of the starting electromagnetic injection valve 9 to inject the fuel into the intake manifold 2. On the other hand, the 1 signal produced: at the output terminal 102 is inverted by the inverter and the inverted 0 signal is then applied to the input terminals of the NAND gates 11., 12, 13 and 14.This closes the NAND gates 11 to 14 and thus prevents the signals produced at the output terminals 100,

I 101;, 10c and 10d of the electronic computing circuit l0 from passing through the NAND gates 11 to 14. Consequently, if the temperatureof the engine 1, when starting is below the preset value, the operation of the regular electromagnetic injection valves 5, 6, 7 and 8 is forcibly prevented so that only the starting electromagnetic injection valve 9 is operated to inject therefrom a readily vaporable fuel thereby ensuring a smooth starting of the engine. As the engine 1 thus started eventually starts rotating by its own effort so that the cranking by the starting motor 29 is no longer required, the starter switch 30 is opened and thus the transistor 34 of the start detector 31 is rendered non-conductive producing a 1 signal at the collector thereof. When this occurs, independently of the output signal of the temperature detector 21, the transistor-39 is rendered conductive thusproducing an 0 signal at the output terminal 10c of the electronic computing circuit 10. The occurrence of this 0 signal results in the de-energization of thestarting electromagnetic injection valve 9 stopping the injection of the fuel therefrom, and simultaneously the 0 signal produced at the output terminal 10e is inverted by the inverter 20 so that the inverted 1 signal is applied to the NAND gates 11, 12, 13 and 14 causing them to open. After the engine has started positively in this manner, the pulse signals produced at the output terminals 10a, 10b, 10c and 10d of the electronic computing circuit 10 for normal operation of the engine are applied in a predetermined sequence to the magnetic coils of the regular electromagnetic injection valves 5, 6, 7 and 8 through the NAND gates 11, 12, 13 and 14 and through the inverter amplifier 15, 16, 17 and 18 where the pulse signals are inverted and amplified. This causes the regular electromagnetic injection valves 5, 6, 7 and 8 to inject the fuel as required by the engine 1. At this time, as with the conventional systems, the regular electromagnetic injection valves 5, 6, 7 and 8 inject, if required, an additional amount of fuel so as to warm up the engine until the temperature of the engine 1 attains another preset value of C, for example, which is different from the one determined by the temperature detector 21. In this case,'such an enrichment for warming up does not give rise to any inconvenience, since the engine has already started.

On the other hand, if the temperature of the engine a 1, when starting, is higher than the preset value established by the temperature detector 2 1,a 0 signal is produced at the output terminal We of the electronic computing circuit 10 so that the starting electromagnetic injection valve 9 does not operate and instead the regular electromagnetic injection valves 5, 6, 7 and 8 come into operation. In other words, since the engine 1 has already warmed up, with no fuel injected from the starting electromagnetic injection valve 9, the engine 1 can be smoothly started without wetting the spark plug by means of the fuel injected from'the regular electromagnetic injection valves 5, 6, 7 and 8.

While, in the first embodiment described above, the operation of the regular electromagnetic injection valves 5, 6, 7 and 8 is prevented and the starting electromagnetic injection valve 9 alone is operated only in case the temperature of the engine 1, when starting, is below the present value, in practice,'whenever the engine 1 is to be started, the operation of the regular electromagnetic injection valves 5 to 8 may be forcibly prevented to allow the starting electromagnetic injectionvalve 9 to operate alone independently of the tempera-- ture of the engine 1. One form of the arrangement for this purpose will be explained with reference to FIG. 3 illustrating a second embodiment of the present invention. In H6. 3, reference numerals identical with those which are used in FIGS. 1 and 2 designate the identical parts or their equivalents, and the collector of the transistor 34 of the start detector 31, i.e., the output terminal is connected to one input of the NAND gates 11, 12, 13 and 14 and the output terminal 10a is also connected to the starting electromagnetic injection valve 9 through an inverter amplifier 41.

The operation of this embodiment is as follows: as the starter switch 30 is closed so that the starting motor 29 is operated to start the engine 1, the transistor 34 of the start detector 31 is rendered conductive producing at its collector a 0 signal which is applied to and closes the NAND gates 11, 12, 13 and 14. When this occurs, the operation of the regular electromagnetic injection valves 5, 6, 7 is forcibly prevented allowing the starting electromagnetic injection valve 9 to operate alone so as to inject a readily atomizable fuel. After the engine 1 has started, the starter-switch 30 is opened so that the transistor 34 of the start detector 31 is rendered nonconductive producing a 1 signal at its collector. This 1 signal is applied to stop the operation of the starting electromagnetic injection valve 9 and simultaneously the NAND gates 11, 12, 13 and 14 are opened. Thereafter, the pulse signals generated at the output terminals 10a, 10b, 10c and 10d of the electronic computing circuit 10 energize the regular electromagnetic injection valves 5, 6, 7 and 8 to inject the fuel to meet the fuel requirement of the engine 1. It should be noted that the present invention is not limited to the embodiments described hereinabove and that various modifications and embodiments can be devised that will fall within the spirit and scope of the present invention. For example, the NAND gates 11, 12, 13 and 14 and the inverter may be incorporated in the electronic computing circuit 10 and moreover these circuit elements may be converted into configurations using negative logic.

lt will thus be seenthat the present invention has a remarkable effect in that since the operation of the regular electromagnetic injection valves 5, 6, 7 and 8 is forcibly prevented while the starting electromagnetic injection valve 9 is in operation, if the temperature of the engine 1 is low and thus the atomization of the fuel injected from the regular electromagnetic injection valves 5, 6, 7 and 8 is poor, the engine 1 may be smoothly started without wetting the spark plug by means of a readily atomizable fuel injected from the starting electromagnetic injection valve 9. There is another remarkable effect in that if the engine 1 has warmed up to the extent that the fuel injected from the regular electromagnetic injection valves 5, 6, 7 and 8 can be vaporized satisfactorily, the engine can be readily and positively started only with the fuel injected from the regular electromagnetic injection valves 5, 6, 7 and 8 without operating the starting electromagnetic injection valve 9.

We claim:

1. In an electrical fuel injection system for internal combustion engines wherein the fuel requirement of an engine is electrically computed by an electronic computing circuit sothat the regular electromagnetic injection valves are energized to inject the fuel by pulse 'signals the time width of which corresponds to the fuel requirement, and wherein a starting electromagnetic injection valve is provided to atomize and inject, independently and exclusively of the regular electromagnetic injection valves, an engine starting fuel when starting the engine, the combination comprising a start detector for detecting the start of the engine and for generating an output signal, and a circuit means connected with said start detector for receiving said output signal of said start detector for preventing the operation of the regular electromagnetic injection valves and for energizing only the starting electromagnetic injection valve to thereby provide an atomized fuel to said netic injection valves, an engine starting fuel when starting the engine, the combination comprising a start detector for detecting the start of the engine and for generating an output signal when said engine is being started, a temperature detector for detecting the temperature of the engine, said detector generating an output signal when the engine. temperature is lower than a preset value, and a circuit means connected with said start detector and said temperature .detector for preventing the operationof the'regular electromagnetic injection valves and for energizing only the starting electromagnetic injection valve when said output signals of said start detector and said temperature detector.are simultaneously generated.

3. An electrical fuel i'njectionsystem according to claim 1, wherein said circuitcomprises:

a logic gate circuit having a first input terminal connected to said electronic computing circuit, a second input terminal connected to said start detector, and a first output terminal 'connectedto said regular electromagnetic injection valves; and

an inverter circuit having an input terminal connected to said start detector, and an output terminal connected to said starting electromagnetic injection valve.

4. The electrical fuel injection system of claim 1 8 wherein said circuit comprises gating means coupling the output of said electronic computing circuit with said regular electromagnetic injection valve,

means response to the output of said start detector for inhibiting said gating means when said internal combustion engine is being started" and for enabling said gating means after said internal combustion engine'is started, and

gating means responsive to the output signal of sai I start detector for energizing'the starting electromagnetic valve. 5. The electrical fuel injection'system of claim 2 wherein said circuit comprises: j

a logic gating circuit having a first input terminal connected'to said electronic computing circuit, an inverter having an input terminal connected to said start detector and an output'terminal connected to the other input terminals of said logic gating circuit, said logic gating circuit having an.

output terminal connected to said regular electromagnetic injection valve wherein said logic gating circuits are inhibited when the output signals of said start detector and said temperature detector are simultaneously generated and wherein said to the output of said start detector and said temperature detector for inhibiting said gating means when said internal combustion engine is being started andthe temperature of said engine is below a preset level, and for enabling said gating means after said engine is started or the temperature of said engine goes above said preset level, and means responsive to the output signal of said start detector and said temperature detector for energizing the starting electromagnetic valve when said engine is being started and when the temperature is below a preset level.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3533381 *Apr 24, 1969Oct 13, 1970Bosch Gmbh RobertTemperature sensitive control circuit for internal combustion engines having a fuel injection system
US3534723 *Mar 11, 1968Oct 20, 1970Stewart Warner CorpDiesel engine manifold air preheater and starting system system employing the same
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4096831 *Oct 4, 1976Jun 27, 1978The Bendix CorporationFrequency modulated fuel injection system
US4171692 *Aug 10, 1976Oct 23, 1979Robert Bosch GmbhFuel injection control system
US4216757 *Mar 16, 1978Aug 12, 1980Robert Bosch GmbhElectrical control circuit, especially for a fuel supply device of an internal combustion engine
US4250849 *Apr 23, 1979Feb 17, 1981Nissan Motor Company, LimitedApparatus for controlling the starting function of an internal combustion engine
US4418674 *Jun 3, 1982Dec 6, 1983Honda Giken Kogyo Kabushiki KaishaElectronic fuel injection control system for multi-cylinder internal combustion engines
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Classifications
U.S. Classification123/179.17, 123/491
International ClassificationF02D41/34, F02D41/06, F02N19/00
Cooperative ClassificationF02N19/00, F02D41/062, F02D41/065
European ClassificationF02D41/06D, F02D41/06D4