Control device for fuel injection pump - has concentric double piston to displace timing characteristic by driver's action, or in response to independent parameter

The device controls the timing of a fuel injection pump and uses a pump (9) driven at engine speed. Fuel is pumped via a damping restriction (13) into a chamber (14) to move an inner piston (6) and hence actuate a control rod (8). The inner piston is contained within an outer piston (3) which is actuated by the pressure in a chamber (23). Fuel is supplied to this chamber from a line (20) by a variable throttle (22), or from an independent source, so that a different engine control parameter can be superimposed. The characteristic curve relating the injection timing with speed can thus be displaced in a parallel manner by an independent parameter.