Fuel injection system for an internal combustion engine

Abstract

A multi-cylinder internal combustion engine is provided with a fuel injection system, which includes a plurality of fuel injection nozzles securely mounted in independent intake passages communicating with combustion chambers of respective cylinders, an air-flow sensor for detecting the amount of intake air to be led into each combustion chamber, a crank angle sensor and a cylinder discrimination sensor for detecting the present stroke timing of each cylinder, a speed sensor for detecting the engine speed and a control unit for outputting a signal to the fuel injection nozzles so that a predetermined amount of fuel may be injected to each cylinder at a predetermined timing on the basis of values detected by the respective sensors. The control unit calculates the injection timing of fuel to be injected into each cylinder so that the injection start timing may be altered in compliance with driving conditions of the engine. The control unit also calculates the amount of fuel to be injected into each cylinder on the basis of at least the amount of intake air and the engine speed. The amount of intake air is detected at a timing which is altered in compliance with the injection start timing and close to this timing.