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Old 04-16-2012, 02:35 PM   #75 (permalink)
jtbo
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Quote:
Originally Posted by serialk11r View Post
Not exactly, look at a BSFC map of a diesel engine, efficiency still goes down quite a bit at partial load. However I think the very high compression ratios and lack of throttle make the losses smaller. I guess a good thing to look at is idle consumption perhaps, you'll notice that a diesel uses less fuel than a gasoline engine of the same displacement when idling, but it probably doesn't even manage to cut idle consumption by 50% (I might be wrong, this is just some number I found once).
Problem is that I have not found BSFC map for anything that would really compare to my all mechanical small turbo diesel engine, I can see maps for more modern ones, also big ones, but nothing for this kind of engine. Modern ones have throttle butterfly, I think VW TDI engines has it too, at least some year model, but I can remember wrong too, does happen often.

I have been trying to look information about diesel and part throttle efficiency, but so far I have not found much of anything, except that Wikipedia quotation which as we all know can be false as anything in there.

I remember that diesel converted to run with ethanol and spark plugs got 40% efficiency with large range of loads, don't know if it does relate to diesel any way though.

It is huge guessing still, also when I have tested different styles I have not been able to make difference that would have had any statistical signification, so it makes guessing even more like guessing.
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