Fuel injection system for an internal combustion engine

A fuel injection system for an internal combustion engine having at least one cylinder, said system comprising:

• a sensor for detecting the rate of engine intake air flow;
• a fuel source operative to supply a fuel under a predetermined pressure;
• a fuel metering device including a housing provided with a fuel inlet port connected to said fuel source and at least one fuel outlet port;
• and
• at least one fuel injector adapted to be mounted on the engine;
• said fuel metering device further including a rotor mounted in said housing for rotation in timed relationship with the engine rotation and a control member mounted in said housing in telescopic relationship to said rotor and operatively associated with said intake air flow sensor so that said control member is axially moved relative to said rotor when the rate of engine intake air flow is varied;
• one of said rotor and control member which is disposed inside the other defining a fuel passage always in communication with said fuel inlet port in said housing;
• said rotor being provided with at least one orifice;
• said control member being provided with at least one orifice;
• the rotation of said rotor relative to said control member moving the orifice in said rotor into overlapping and communicating relationship to the orifice in said control member;
• the arrangement being such that the angle of rotation of said rotor over which the communication between said orifices lasts is varied in accordance with the variation in the rate of engine intake air flow to thereby meter a fuel charge to be fed into the engine;
• said fuel outlet port in said housing being communicated with said fuel passage when said orifices are overlapped and communicated with each other to allow the fuel to flow from said fuel passage through said orifices and said fuel outlet port;
• a fuel delivery circuit means for delivering the thus metered fuel charge to said fuel injector;
• said fuel delivery circuit means including said fuel outlet port in said fuel metering device housing;
• and
• an orifice member disposed in said fuel delivery circuit means to provide therein a fixed restriction orifice having a fuel flow cross-sectional area smaller than the area over which said orifices are overlapped and communicated with each other, whereby the amount of each fuel charge to the engine is solely dependent upon the duration of the communication between said orifices in said rotor and said control member, wherein the orifice in said rotor and the orifices in said control member are all triangular and arranged such that an apex of the orifice in said rotor and an apex of each of the orifices in said control member are overlapped with each other when the orifice in said rotor is moved by the rotation of said rotor relative to said control member.