Method and device for operation of a high pressure fuel pump

A device for the operation of a high pressure pump in a system for fuel injection in a combustion engine, wherein

• the high pressure pump comprises at least two pump elements;
• a low pressure part of the system and an accumulator tank for fuel injection to the combustion engine, the two pump elements are connected in parallel between the low pressure part and the accumulator tank;
• each pump element has a cylinder with a pump chamber and a moveable piston in the cylinder for pumping, the cylinder having a connecting opening to the low pressure part, an inlet valve arranged in the connecting opening, the inlet valve being controllable to control the flow of fuel into the pump chamber;
• an element configured to control the pump elements to deliver a fuel pressure in the accumulator tank, according to a reference value requested for this purpose;
• the device comprises:
• elements configured to detect the occurrence of a predetermined partial load condition in the combustion engine, at which one of the pump elements is capable of alone delivering a fuel pressure requested in the accumulator tank according to a first reference value (P1), and is capable to achieve a reproducible increase of the fuel pressure to a second reference value (P2), in the event the one element detects such occurrence, the control device is configured to control the high pressure pump's pump elements so that the one of the pump elements alone delivers a fuel pressure in the accumulator tank according to the first reference value, and to control changing the reference value of the fuel pressure in the accumulator tank to the second reference value while the control of the high pressure pump's pump elements is maintained, so that only the one pump element alone delivers the fuel pressure requested in the accumulator tank;
• during the build-up of the fuel pressure in the accumulator tank from the first reference value to the second reference value, means configured to determine the fuel pressure in the accumulator tank as a function of time and a device configured to compare development of the fuel pressure in the accumulator tank during the build-up thereof with stored values of such developments, in order to produce information regarding the pump element's performance ability.