Fuel injection control based on spill port opening timing correction

Abstract

A fuel injection control system for internal combustion engine comprises a fuel injection pump including a plunger slidably reciprocating in synchronism with rotation of the engine and a spill port establishing communication between a low pressure chamber and a pump chamber. An electronic control unit is responsive to engine operating conditions for the determination of fuel injection time period and controls the solenoid-operated valve to close the spill port in response to the requirement of fuel injection into the cylinder and open the same to terminate the fuel injection. The fuel injection control system further comprises a circuit including two fixed resistors and two adjusting resistors so that first and second voltage signals are developed at its terminals. The two adjusting resistors respectively determine the value of the voltage signals. The first voltage signal is regulated to correspond to the response time lag inherent in the solenoid valve and the second voltage signal is regulated to correspond to the error of the generation timing of the detection signal of a reference plunger position detector. The correction of fuel injection time period is made on the basis of the first and second voltage signals. pg,4