d-valves?

[dieselpower]

ok,
so what exactly do the delivery valves do? and what pressure do they open at? has anyone ever tried changing that pressure? or the actual size of the valve? i was just reading up on the pump and seen those which i havent seen before. i was just wondering what exactly they were there for.



Mark

[QuickTD]

The purpose of the delivery valves is to relieve the pressure in the injection lines after injection has taken place. This prevents nozzle dribble or secondary injection due to the reflected shock wave. They also create stable pressure conditions in the line for the next injection. The opening pressure is very low, likely ~100psi or less, judging from the spring. I don't think changing the pressure would have much effect on output.

 The dodge cummins crowd has actually been able to increase the output of the inline pump enough that the delivery valves needed modification to increase flow.  Bear in mind that they are increasing engine output over 300% in many cases and they use a different type of delivery valve in direct inject engines. I don't think we're quite at that level yet.