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Old 07-01-2009, 03:23 PM   #26 (permalink)
stevey_frac
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Join Date: Jun 2008
Location: Cambridge, ON
Posts: 240

Jalilah - '07 Chevrolet Cobalt LT
90 day: 40.57 mpg (US)
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Quote:
Originally Posted by dutchboy View Post
This sounds interesting...I have read about water injection before but never really went anywhere with it. I imagine that this idea (liquid gasoline injection) would probably accomplish a similar goal, which is more advanced timing by reducing knock if I recall correctly.

Are most automobile injectors aimed toward the center of the piston though? Are there "stream" injectors that would fit in place of OEM injectors?
Most Injectors in gasoline cars aren't even inside the combustion chamber. They fire with the air going in.

Some vehicles, such as the Cobalt SS turbo, have Direct injection. This actually allows them to run super lean under some conditions.

However, they don't directly inject a stream of gasoline. This would result in very poor emissions under most cases. You want to atomize the fuel as much as possible to get a complete burn. You need as much surface area as possible. At higher RPM you only have a fraction of a second to completely burn all the gasoline as much as possible. Even then, most gasoline engines still send unburnt fuel down to the cat to be burned.

For a diesel engine, the scenario is different. The reason why they need to warm fuel is in order to get it to atomize better. As the fuel warms, it's viscosity lowers. The lower viscosity allows the fuel to come out of the injector as a finer mist. This allows a more complete burn, because there is more surface area.

Warm diesel fuel technically would have some thermodynamic influence on the burn temperature... but it would be so small as to be statistically insignificant, observable only on a calculator.

Warm gasoline in the winter might actually have a bit of merit. In very cold areas, gasoline won't vaporize very well. But that being said, no mater WHAT you do, your not gonna get great mileage at -30.
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