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Old 02-05-2010, 12:34 AM   #19 (permalink)
El Duende
EcoModding Lurker
 
Join Date: Jan 2010
Location: USA
Posts: 33

QG - '02 Nissan Sentra GXE
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Quote:
Originally Posted by Christ View Post
Internal combustion engines, being of the adiabatic sort of beast family, are inherently more efficient when they're "soaked" closer to combustion temp. The hotter intake air is proven to be more efficient per volume of intake because there is less tendency of the combustion heat to soak into the engine (the engine has already reached equilibrium with the intake air, so less heat is pushed into the metal on combustion because of the already higher cylinder wall temp), and less energy from heat necessary to increase the temperature of the intake volume.

There have been published studies which show these, and other examples, as benefits of increased engine temperature and intake air temperature, where efficiency is concerned.

To clarify the term - Efficiency, in this case, is the amount of energy derived from an amount of fuel during combustion, compared to the actual energy content of the consumed amount of fuel.

The WAI in general doesn't lean the A/F ratio - it reduces the dynamic displacement of the engine, and reduces pumping losses. A less viscous fluid is ALWAYS easier to move. (Air is a fluid.)
I had to look up "adiabatic" in the dictionary. No match found. I see what you mean by "soaking" the metal by way of the intake charge. Don't worry about losing precious heat with cooler air because the combustion chamber will inevitably heat up. Pressure in the engine bay will keep hot air around the motor, too. You're telling me that an already warm engine will be a more ideal environment for combustion than a cooler one. Sucks for my MPGs, it's cold outside! That explains why this demographic has such a high demand for engine block heaters. I thought it was compression or spark plug location that affected thermal-effeciency. (The term you clarified, but didn't specify.) Swapping in a CAI/SRI also reduces mechanical effort along with more HP. There's no use in keeping the intake system hot. The coolant is in charge of keeping the head at the temperature it needs to be, not the outside air.

Not trying to be a smart-ass, but I'd like to see a link to one of those studies.
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