- #1
Charly Segaert
- 4
- 0
Hello everyone,
I have a question about a common rail high pressure pump.
Most common rail pumps make use of a pressure control-valve which controls the amount of fuel that goes to the plunger. This way it is possible to control how much fuel goes to the rail, so it controls the pressure.
But... If you are going downhill without giving any throttle (no injector opens for a while), the engine still spins and therefore the pump spins as well. When the pump spins, but the pressure control-valve is fully closed, what happens? Is there a minimum amount of fuel that always goes to the plunger? And doesn't this keep on pushing more fuel in the rail, thus increasing pressure? Or doesn't the plunger get any fuel at all, creating a kind of vacuüm?
It's a small thing I don't yet understand. Thanks in advance
Charly
I have a question about a common rail high pressure pump.
Most common rail pumps make use of a pressure control-valve which controls the amount of fuel that goes to the plunger. This way it is possible to control how much fuel goes to the rail, so it controls the pressure.
But... If you are going downhill without giving any throttle (no injector opens for a while), the engine still spins and therefore the pump spins as well. When the pump spins, but the pressure control-valve is fully closed, what happens? Is there a minimum amount of fuel that always goes to the plunger? And doesn't this keep on pushing more fuel in the rail, thus increasing pressure? Or doesn't the plunger get any fuel at all, creating a kind of vacuüm?
It's a small thing I don't yet understand. Thanks in advance
Charly