Engine Learning Week

David G

Well-known Member
I spent most of the week working on adding fuel injection to the big natural gas engine, I was incorrect, this unit was 10,000 HP, the unit next to it was 7000 HP.

I saw the effects of retarded timing on heat generation. We needed to get the turbo hot enough to work, so we retarded the timing a few degrees after starting to generate heat to do that.

They added a pressure transmitter in each head that showed the pressure pulse created during ignition. We got to see the effects of that pulse by varying timing and boost.

This engine adds fuel in response to the governor, much like a diesel, then we had to control the turbo to make the air to fuel ratio correct. I always wondered how they did that in a diesel.

It was a very educational week. The engine is running, and are working on determining the correct data to model with.
 
"This engine adds fuel in response to the governor, much like a diesel, then we had to control the turbo to make the air to fuel ratio correct. I always wondered how they did that in a diesel."

with the exception of during acceleration, a diesel engine operates on the lean side of stoichiometric (there is always excess air).
 
A natural gas engine is much more particular about air fuel ratio than a deisel. The gas engine has fuel in it and then it fires with a spark plug, so it is easy to get into preignition, which is a silent killer. The pressure sensors allowed them to see the firing pressure trace and adjust ignition and fuel to stay out of preignition and detonation.
A diesel engine burns the fuel as it is injected, so it less likely to have preignition or detonation, but not impossible.
Another interesting fact, these engines are probably turning about 300 RPM, as opposed to our tractors turning 2 to 3 thousand, just think of the huge torque these monsters have.

IMHO
Rich
 

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