Diesel engine starter torque 1

[scoelco]

Is there a rule of thumb, or an existing data chart that will help determine the operating torque required, rpm and gear ratio (starter gear to flywheel gear) of pickup and light truck diesel engine starters?

I am particularly interested in the torque and rpm required to start diesel powered Ford, Chevy, GM and Dodge pickup and light truck engines.

 

[MintJulep]

Well, basically the engine is an air compressor before it starts to run, so it seems that the formulas used to calculate the power required for a compressor would get you what you need.

I have them somewhere at the office. If GregL or one of the other actual auto guys doesn't chime in, and I remember, I'll post them next week.

 

[JStephen]

Pull the starter out of one, and measure the torque, speed, etc.

 

[GregLocock]

I don't think there is an easy answer to the required rpm. For instance, I have known an engine that could be started at 0 rpm, ie you connected the ignition and , flicked the contact breaker, and it would start. Equally I have had many motorbikes that would not start until they were doing several hundred RPM.

Modern car engines seem to start at about 150 rpm, for what that is worth. My old Toyota will certainly /run/ at 300 rpm.

All the above is for SI engines, I would have thought diesels would be more complex.





Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[MintJulep]

For adiabatic compression, with zero clearance volume:

indicated horse power = m.e.p x LAN / 33000

where m.e.p is mean effective pressure
m.e.p = 3.534 x P1 x (r^0.283 -1)

and r = P2/P1

pressures are psia

L is piston stroke in feet
A is the piston area in squre inches
N is the number of effective strokes of piston per minute

This should at least get you in the ballpark.