If one presses the accelerator pedal when a diesel engine is running, as a rule, more fuel is injected. The radial piston pump regulates, through the delivery amount, the radially arranged high-pressure pistons and the fuel amount to be injected, thus, the performance development of the diesel engine.
How it works
The volume regulation occurs, in that the brown coloured rotary part 'b' is shifted axially. With the mechanically and the electronically regulated pump, a travel limitation, with diagonal edges for the roller tappets, shifts in such a way that the radial pistons do not carry out the full stroke of the cams on the cam ring (limitation of the supply quantity). This travel limiter is, when electronically regulated, shifted axially through hydraulic pressure which is adjusted by the electric magnetic valves of the control device.
With the newer electronic systems, (e.g., from Bosch) the radial pistons always carry out the full stroke, the generated pressure is however, degraded in the flow-back, at a point in time to be determined by the control device.