Solenoid-valve-controlled fuel injection device

Claim 1

A solenoid-valve-controlled fuel injection device comprising: a fuel injection pump having a pump cylinder, a plunger rotatably and reciprocably disposed in said pump cylinder in a fluid-tight manner and defining a fuel pressurization chamber between a distal end of the plunger and the pump cylinder, a drive shaft rotatable in synchronism with an output shaft of an internal combustion engine, means responsive to rotation of said drive shaft for reciprocably displacing said plunger to pressurize fuel in said pressurization chamber, and a fuel chamber for being supplied with fuel from a fuel tank in response to rotation of said drive shaft, whereby the pressurized fuel can be fed into cylinders of said internal combustion engine; a solenoid valve for selectively opening and closing a communication passage by which said pressurization chamber and said fuel chamber communicate with each other; valve opening delay time detecting means for detecting a valve opening delay time of said solenoid valve; valve closing delay time detecting means for detecting a valve closing delay time of said solenoid valve; valve closing period calculating means for calculating a valve closing time of said solenoid valve according to operating conditions of said internal combustion engine; target fuel injection time calculating means for calculating a target fuel injection time according to the operating conditions of said internal combustion engine; determining means for determining whether at least a rotational speed of said internal combustion engine is in a predetermined rotational speed range; and averaging means for averaging valve opening delay times detected by said valve opening delay time detecting means when said rotational speed is determined to be in said rotational speed range by said determining means, whereby a drive pulse having a pulse duration determined in view of the valve opening delay time averaged by said averaging means is applied to said solenoid valve.