Frequency Valve: Description and Operation

The frequency valve resembles an electrically controlled fuel injector that has been modified to accept fuel lines at the inlet and outlet. The valve is installed in-line between the lower control plunger chamber and the fuel return, and modulates pressure in the lower plunger chamber depending upon signals from the ECU. Modulating pressure in the lower plunger chamber alters the pressure differential between the control plunger inlet and outlet, allowing the quantity of fuel supplied to the injectors to be controlled independent of control plunger position.