Fuel injection control system with split fuel injection for diesel engine
First Claim
1. A fuel injection control system for injecting fuel directly into a combustion chamber of a diesel engine, comprising:
- angular position detecting means for producing an angular position signal each time a crankshaft of the diesel engine rotates through a predetermined angle;
startup detecting means for detecting a startup condition of the diesel engine;
pre-jet injecting means for injecting a pre-jet of fuel into the combustion chamber in synchronism with the angular position signal produced by said angular position detecting means when the startup condition of the diesel engine is detected by said startup detecting means; and
main-jet injecting means for injecting a main jet of fuel, which is larger in quantity than said pre-jet of fuel, into the combustion chamber after said pre-jet of fuel is injected by said pre-jet injecting means when the startup condition of the diesel engine is detected by said startup detecting means.
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Abstract
At diesel engine startup, a fuel injection control system for the diesel engine injects a pre-jet of fuel into a combustion chamber in synchronism with a signal indicative of an angular position of the crankshaft of the diesel engine. After the pre-jet of fuel has been injected, the fuel injection control system injects a main jet of fuel which is larger in quantity than the injected pre-jet of fuel. Even when the engine rotational speed is low and subjected to variations as at engine startup, the pre-jet of fuel is reliably injected into the combustion chamber at a desired time. The pre-jet of fuel which is injected and ignited prior to the main jet develops an easily ignitable, activated condition in the combustion chamber. The subsequently injected main jet of fuel can thus be easily ignited by the activated condition in the combustion chamber. The diesel engine can be started quickly and smoothly without fail.
69 Citations
20 Claims
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1. A fuel injection control system for injecting fuel directly into a combustion chamber of a diesel engine, comprising:
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angular position detecting means for producing an angular position signal each time a crankshaft of the diesel engine rotates through a predetermined angle; startup detecting means for detecting a startup condition of the diesel engine; pre-jet injecting means for injecting a pre-jet of fuel into the combustion chamber in synchronism with the angular position signal produced by said angular position detecting means when the startup condition of the diesel engine is detected by said startup detecting means; and main-jet injecting means for injecting a main jet of fuel, which is larger in quantity than said pre-jet of fuel, into the combustion chamber after said pre-jet of fuel is injected by said pre-jet injecting means when the startup condition of the diesel engine is detected by said startup detecting means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A fuel injection control system for injecting fuel directly into a combustion chamber of a diesel engine, comprising:
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angular position detecting means for producing an angular position signal substantially when a piston in the combustion chamber reaches the top dead center in a compression stroke of the diesel engine; startup detecting means for detecting a startup condition of the diesel engine; main-jet injecting means for injecting a main jet of fuel into the combustion chamber substantially when the piston reaches the top dead center in the compression stroke, in synchronism with the angular position signal produced by said angular position detecting means when the startup condition of the diesel engine is detected by said startup detecting means; and pre-jet injecting means for injecting a pre-jet of fuel, which is smaller in quantity than said main jet of fuel, into the combustion chamber to produce an activated condition in the combustion chamber before said main jet of fuel is injected into the combustion chamber by said main-jet injecting means when the startup condition of the diesel engine is detected by said startup detecting means.
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19. A fuel injection control system for injecting fuel directly into a combustion chamber of a diesel engine, comprising:
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angular position detecting means for producing an angular position signal each time a crankshaft of the diesel engine rotates through a predetermined angle; rotational speed detecting means for detecting a rotational speed of the diesel engine; startup detecting means for detecting a startup condition of the diesel engine; normal injecting means for injecting fuel into the combustion chamber at a time which is determined based on the angular position signal produced by said angular position detecting means and a period of time that has elapsed from the angular position signal and varies depending on the rotational speed detected by said rotational speed detecting means; and startup injecting means for injecting a pre-jet of fuel into the combustion chamber at a time which is determined based on the angular position signal produced by said angular position detecting means irrespective of the rotational speed detected by said rotational speed detecting means, and for injecting a main jet of fuel, which is larger in quantity than said pre-jet of fuel, into the combustion chamber subsequently to said pre-jet of fuel, when the startup condition is detected by said startup detecting means.
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20. A fuel injection control system for injecting fuel directly into a combustion chamber of a diesel engine, comprising:
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angular position detecting means for producing an angular position signal each time a crankshaft of the diesel engine rotates through a predetermined angle; rotational speed detecting means for detecting a rotational speed of the diesel engine; startup detecting means for detecting a startup condition of the diesel engine; normal injecting means for injecting fuel into the combustion chamber at a time which is determined based on the angular position signal produced by said angular position detecting means and a period of time that has elapsed from the angular position signal and varies depending on the rotational speed detected by said rotational speed detecting means; and startup injecting means for injecting a main jet of fuel into the combustion chamber at a time which is determined based on the angular position signal produced by said angular position detecting means irrespective of the rotational speed detected by said rotational speed detecting means, and for injecting a pre-jet of fuel, which is smaller in quantity than said main jet of fuel, into the combustion chamber prior to said main jet of fuel, when the startup condition is detected by said startup detecting means.
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Specification