2 - Deactivator of the 3rd piston of the high pressure fuel pump
2.1 - Role.
Role of the deactivator of the 3rd piston of the high pressure fuel pump :
To reduce the power absorbed by the high pressure pump if the vehicle is used at low load.
To limit the high pressure quickly in the event of a problem.
When the 3rd piston deactivator is not energised :
l The fuel suction valve is held against its seat by the spring .
l The cylinder is closed.
l The action of the pump shaft cam leads to a pressure being created.
l The fuel pressure lifts the delivery valve .
l The fuel is directed towards the high pressure outlet of the pump.
When the 3rd piston deactivator is energised :
l The push rod raises the suction valve from its seat.
l The cylinder is open:No pressure is created.
l The fuel is directed towards the low pressure part of the high pressure pump.
Control : injection ECU.
Type : "all or nothing" control through earth.
When the 3rd piston deactivator is energised:the pump operates on 2 pistons.
When the 3rd piston deactivator is not energised:the pump operates on 3 pistons.
2.1 - Role.
Role of the deactivator of the 3rd piston of the high pressure fuel pump :
To reduce the power absorbed by the high pressure pump if the vehicle is used at low load.
To limit the high pressure quickly in the event of a problem.
When the 3rd piston deactivator is not energised :
l The fuel suction valve is held against its seat by the spring .
l The cylinder is closed.
l The action of the pump shaft cam leads to a pressure being created.
l The fuel pressure lifts the delivery valve .
l The fuel is directed towards the high pressure outlet of the pump.
When the 3rd piston deactivator is energised :
l The push rod raises the suction valve from its seat.
l The cylinder is open:No pressure is created.
l The fuel is directed towards the low pressure part of the high pressure pump.
Control : injection ECU.
Type : "all or nothing" control through earth.
When the 3rd piston deactivator is energised:the pump operates on 2 pistons.
When the 3rd piston deactivator is not energised:the pump operates on 3 pistons.