Chemistry of combustion and Charles's Law
11-28-2008, 05:57 AM
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Chemistry of combustion and Charles's Law I am in chemistry and it has disambiguated some interesting confusion. There is no such thing as one pressure in a combustion chamber and a heat that doesn't correspond. For example, any car that has 2,200 degrees faranheit in the chamber has the exact same psi pushing the piston down as any other car having 2,200 degrees faranheit in the chamber, reguadless of boost pressure, intercoolers, ect. I just thought I would share because I found it very interesting, hope you guys do too, im sure some of you real smart ones already knew
11-28-2008, 06:12 AM
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Never mind that's under Ideal gas conditions, the theory brakes down under non-ideal gas conditions where intermolecular interactions become significant. Interesting stuff though
11-28-2008, 11:55 AM
#3
A running engine is quite a complex system, and rules such as the ideal gas law or charles' law just don't get the job done.
The piston and chamber on their own are a polytropic process, but a simple polytropic model needs heat transfer characterized to become anywhere near accurate. The combustion process is extraordinarilly complex (especially with complex gasolines like we have now), and it must be understood to estimate the heat release and pressure rise in the system. Combustion is usually modeled by making some assumptions and using a more basic burn model. Then, it all gets weird when the intake and exhaust valves open.
Your thought about temperature is OK, but please consider the volume of the chamber and the timing of that temperature before presuming that all things are equal.
Keep working on it. With the web at your fingertips, you can learn quite a bit quickly.
The piston and chamber on their own are a polytropic process, but a simple polytropic model needs heat transfer characterized to become anywhere near accurate. The combustion process is extraordinarilly complex (especially with complex gasolines like we have now), and it must be understood to estimate the heat release and pressure rise in the system. Combustion is usually modeled by making some assumptions and using a more basic burn model. Then, it all gets weird when the intake and exhaust valves open.
Your thought about temperature is OK, but please consider the volume of the chamber and the timing of that temperature before presuming that all things are equal.
Keep working on it. With the web at your fingertips, you can learn quite a bit quickly.
