Generating an engine help

What kind of engine? How detailed are you looking to get? For example, with an internal combusion engine, you could go as far as simulating the combustion numerically, and apply the fluid pressure to piston heads that get translated into torque to turn the drive shaft and build up RPM's. Such a simulation is complex.

So, I would say a simple idealistic simulation of the thermodynamic cycles involved and an idealistic conversion of energy into torque is probably be what you're looking for. Here's a reference. I can't vouch for it, it isn't necessarily easy to use, and doesn't really go into application of work to generate torque, but it does represent the idea of simulating simple thermodynamic cycles for an internal combustion engine. It may get you started.

Internal Combustion Engine Cycles

[Edited by - grhodes_at_work on October 18, 2008 11:29:11 PM]

Thanks for the reply Graham,
Unfortunately I think this may be way over kill for what I need.
I guess the actually physics are irrelevant, what just trying to simulate a realistic looking acceleration a value.

So for example: the rpm on a turbine when started will very slowly increase over the first few seconds, then gradually the rpm will dramatically increase as it builds speed. However the acceleration will gradually die down again as the rpm reaches its peek.
Its not a steady consistent increase.

Its a simple curvy graph typed algorithm, Im just struggling to work out how to write it.

Ah, ok. I bet you could find some performance curves, if you used the right search terms.