Patent attributes
A gasoline unit injector includes a high speed, high force actuator such as a magnetrostrictive or piezoelectric actuator. The actuator operates a positive displacement diaphragm pump. The pumping volume is isolated from a supply rail by an inlet check valve, and is isolated from the engine manifold by an outlet check valve. Each of the check valves includes a disk having a central anchor and a peripheral valve seat. Diaphragm movement reduces pump volume and thereby displaces fuel at high pressure through outlet valve. Fuel spray is formed by geometry of outlet valve, the frequency of actuation, and mass and pressure of the displaced fuel. Relaxation of actuator, and therefore diaphragm, increases pump volume and thereby draws fuel into pump volume through the check valve.
