Fuel injection control system for electromagnetic valve-controlled fuel

Abstract

A method and a system are disclosed for controlling the amount and advance of fuel injection of a diesel engine using an injection pump of the type which defines the fuel supply period and the compression period, alternately, in synchronism with explosion-exhaustion and intake-compression strokes of each cylinder of the engine, and includes first and second pressure chambers to be supplied with fuel through first and second electromagnetic valves, respectively, during the fuel supply period, and the fuel in the amount equivalent to the fuel amount supplied to said second pressure chamber being injected into the cylinder at an injection timing determined from the total amount of the fuel supplied to said first and second pressure chambers. The open time intervals of the first and second electromagnetic valves are determined from the fuel amount to be injected into each cylinder and the injection timing advance which are determined in accordance with the engine operating conditions. The opening starting time points of the electromagnetic valves are selected in such a manner as to open the two valves for the above-determined time intervals respectively within the fuel supply period and to minimize the overlap of the open times of the two valves.