There is a lot of things happening during combustion. For instance I know in a gas engine that leaning the fuel mixture will produce higher exhaust temperatures. This is not because because the combustion is hotter (it isn't), but because the leaner mixture causes the timing of the explosion to change. In fact, it as the mixture gets leaner, it will move closer to when the exhaust valves are open, that is why the exhaust is hotter.

I can't speak for diesel combustion. In a gasser, you have a spark to start the process. In a diesel, it's the flashpoint for temperature as a pressure increase causes the temperature to rise.

Question: Does the mixture change the temperature of the flashpoint?

Changing the temperature where you start cerainly would effect the timing of combustion since you won't have to compress as much to get to the flashpoint.

Is this right, or am I complicating things?

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Michael LaFleur

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