The control valve has two chambers separated by spring loaded diaphragms. The system can be used e.g. for controlling exhaust gas feedback valve. The contact pressure of the plunger does not exert a displacing force on the system can and this ensures that correct quantities of exhaust gas are fed back. The input pressure chamber is penetrated by a spring loaded plunger, is guided in a diaphragm plate acting as a valve. This arrangement has a hole which connects the input pressure chamber by the diaphragm plate valve with the control pressure chamber.
