Electronically controlled distributor type fuel injection pump for internal combustion engines

Claim 1

A distributor type fuel injection pump for an internal combustion engine, comprising: a suction space filled with fuel under pressure variable as a function of the rotational speed of said engine; a plunger driven by said engine for concurrent reciprocating and rotative motion to effect suction of fuel from said suction space into a pump working chamber defined by said plunger at one end thereof, pressure delivery of fuel from said pump working chamber and distribution of the fuel into cylinders of said engine; a plurality of suction ports formed in said plunger and identical in number with the cylinders of said engine, said suction ports communicating with said pump working chamber; a first communication passageway communicating said suction space with said pump working chamber; a second communication passageway having a restriction therein, said second communication passageway being disposed to sequentially register with said suction ports as said plunger rotates for communicating said suction space with each of said suction ports that registers with said second communication passageway; a solenoid valve disposed to selectively open and close said first communication passageway; a selector valve operable to assume, independently of the opening and closing action of said solenoid valve, a first valve position wherein said first communication passageway is closed and simultaneously said second communication passageway is opened, at the start of said engine, and a second valve position wherein said second communication passageway is closed and simultaneously said first communication passageway is opened, during operation of said engine other than at the start of said engine; and control means operable in response to operating conditions of said engine to control said solenoid valve to alternately open and close so as to achieve required fuel injection quantity and required injection timing.