Pressure and volume change problem

[monkey55]

I have the inlet port pressure vs time curves for a particular engine speed. I want to be able to modify these to get an estimate of the curves for other engine speeds.

So basically this is an expansion problem,the volume change is known(and max volume change is constant), but the rate of change of volume with time(dV/dt) changes.I know the change in dV/dt from the change in engine speed.

I can change the time axis on the curves easily by knowing the engine speed.But how do i change the value of the pressure change(drop)? surely as the engine speed (dV/dt) increases, the amount of pressure drop should also increase!?...im in the UK so SI equations would be much appreciated,we're not taught imperial!

 

[LightHero]

This is a tricky problem and you may have to use some trial-and-error to get the right answer. One way to approach it would be to assume that the pressure drop is proportional to the rate of change of volume, i.e. dP/dt ∝ dV/dt. Then you can calculate a scaling factor, k, such that:dP/dt = k*dV/dtThen you can use this scaling factor to modify your original curves. For example, if you want to modify the curves for double the engine speed, then you would multiply the pressure drop in each point by 2*k.