Timing control valve for hydromechanical fuel system

摘要

An infinitely variable hydromechanical timing valve, for a fuel supply system for an internal combustion engine, is provided with a housing having a valve seat therein, and a timing control plunger mounted for reciprocation within the housing toward and away from the valve seat. A first side of the timing control plunger is acted upon by a pressure which varies as a function of engine load while a second side of the timing control plunger is acted upon by a pressure which varies as a function of engine speed. Furthermore, the timing control plunger has an orificed flow passage therethrough, one end of which is in communication with a timing flow of fuel from the pump and an opposite end of which timing flow passage communicates with a timing fluid supply rail. As a result, a variable flow area is defined by the circumference of the orifice of the orificed flow passage through the plunger and the distance of the orifice from the valve seat as a means for controlling the pressure of the timing flow communicated to the timing fluid supply rail by a throttling of the timing flow from the pump in a manner which is a function of the pressures acting on the timing control plunger. The pressure of the timing flow from the valve can be controlled in accordance with either a fixed or variable ratio between it and the speed responsive pressure acting on the timing plunger.