I have an engine ( 72240 kW... ) , probably the biggest internal combustion engine in the world and this engine has no camshaft. Instead it has an hydraulic system which controls the combustion, the valves etc. Due to internal leakages on the proportional valves it is difficult to raise the pressure.

Will it make any difference if I install a pump with bigger capacity, or will the leakages just be greater and the pressure will not get higher?

  • $\begingroup$ I feel like rebuilding the proportional valves is probably a better option. $\endgroup$
    – Tiger Guy
    Jun 2, 2021 at 19:51
  • $\begingroup$ You have not stated clearly what the problem is. Are you saying that hydraulic fluid leaks are so great that the peak pressure supplied by the hydraulic pump is not sufficient for proper operation? All pumps have a Characteristic Curve, plotting the relation between flow rate and exit pressure. With increasing flow (leakage) exit pressure drops. If you change the pump, use one that has a characteristic curve showing the pressure you want at the same leakage rate. You can determine the leakage rate by noting the current pressure on your characteristic curve. $\endgroup$
    – ttonon
    Jun 4, 2021 at 18:02

1 Answer 1


It depends on the type of leak and its geometry.

If we assume the leak source is one or a few small orifices, using a more powerful pump should help raise the pressure.

The orifice equation is this:

$$ Q= CA\sqrt{2gh}$$

  • Q discharge

  • C orifice coefficient (ranging around 80%)

  • A area of the orifice

  • h is the head

Therefore, since the extra leak is related to only the square root of extra head generated by a better pump, adding an extra head of pressure is helpful.

  • $\begingroup$ Thank you! But the pressure cannot be raised If i install a pump that provides more flow will it make things better? $\endgroup$ Jun 2, 2021 at 18:01
  • $\begingroup$ almost all the pump's performance charts show an increased head related to increase in flow. you should check the vendor's specs. $\endgroup$
    – kamran
    Jun 2, 2021 at 18:41

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