Fuel injection control system for automobile engine
AssigneeFuji Jukogyo Kabushiki Kaisha
InventorTakashi Matsuura
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Abstract
After an injector current for opening a fuel injector is fed thereto, energization on the fuel injector is stopped to reduce the injector current towards a holding current level for keeping the fuel injector at an open state, a flywheel circuit being inoperative. Before a closed loop for controlling the injector current at the holding current level is formed, the flywheel circuit is made operative, whereby an influence of the operational delay of a circuit forming the closed loop can be reduced and further the injector current can be swiftly transferred to the holding current level before it falls largely.
Claims7
A fuel injector drive circuit having a flywheel circuit for controlling a drive current of a fuel injector, comprising:
- means for raising said drive current from a zero level to a high level so as to open said fuel injector;
- means for holding said drive current at said high level for a predetermined time;
- means for reducing said drive current from said high level while said flywheel circuit is inoperative;
- flywheel circuit control means for generating an operating signal and for operating said flywheel circuit responsive to said signal while said drive current is being reduced;
- and
- closed loop control means for holding said drive current at a low level by a closed loop control so as to keep said fuel injector open while said flywheel circuit is operative.
A method of injecting a fuel directly into a cylinder of an internal combustion engine having, a fuel injector inserted through a cylinder head, a drive circuit for generating a drive current to control said fuel injector, and a flywheel circuit connected to said drive circuit for economizing an electric current of driving said fuel injector and for stabilizing an amount of said fuel to be injected, comprising:
- raising said drive current from a zero level to a predetermined high level;
- holding said drive current at said high level for a predetermined time period;
- reducing said drive current from said high level while said flywheel circuit is inoperative;
- operating said flywheel circuit while said drive current is reduced;
- and
- holding said drive current at a predetermined low level while said flywheel circuit is operative.
Dependencies are inferred from the claim text.