P07.13-0248-81
Function
The pump internal pressure (B) of approx. 8 bar acts on the adjusting piston (11/10) and moves it against the force of the spring (11/10a). It is possible to set any desired position of the adjusting piston by pulsing the injection timing solenoid valve (Y60), as a result of pressure reduction to the fuel pump return flow (R). When the adjusting valve is continuously opened (pressure reduction), retarded start of injections are set. If the solenoid valve is fully closed (pressure increased), advanced start of injections are set. The adjusting valve is closed when deenergized.
The maximum pump internal pressure exists when the engine is idling.
Illustration shows adjusting piston in middle position,
engine idling
11/10 Adjusting piston
11/10a Spring
11/10b Restrictor 0.6 mm
B Pump internal pressure (approx. 8 bar)
R Pressure in fuel pump return flow
Y60 Injection timing solenoid valve