# How to determinate instantaneus torque

1. Jul 23, 2010

### dot_francesco

Hi guy, sorry for my english

I've to determinate a math equation to describe the real instantaneus torque aboute a v12 diesel engine

I've this input, the nominal torque 400 Nm at 1400 rpm, ?irregular degree?=0.05

like this figure

[PLAIN]http://www.epi-eng.com/images/Engine/ET-X-V12.gif [Broken]

thanks to all

Francesco

Last edited by a moderator: May 4, 2017
2. Jul 23, 2010

### brewnog

Tricky one.

I would model this by using cylinder pressure curves to calculate instantenous force on the connecting rod, and geometrically convert this into a torque. Overlay this for each cylinder. That gives you the firing input. You might then want to make some assumptions about torsional vibration if you have information about crankshaft stiffnesses and rotating inertias.

3. Jul 23, 2010

### CSimionescu

Hi dot_francesco,

I think I could help if you give me more data. We need to give me the following parameters: compression ratio [-], nominal power[kW] and the speed power[rot/min].

4. Jul 23, 2010

### dot_francesco

this is a pubblic data sheet take from marine.cummins.com

the V angle is 60°

thanks to all!

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