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-   -   Engine Temps - Coasting To a Stop (https://www.fuelly.com/forums/f8/engine-temps-coasting-to-a-stop-4217.html)

SVOboy 04-08-2007 08:18 PM

I didnt feel like saying all that. If the car it in gear, 0 throttle, at 1000 rpms there will be no fuel cut, and therefore no engine braking. Only when engine braking (as defined by the engine no longer igniting gasoline and using the friction of pumping air to slow the car down) is happening will you have a fuel cut.

omgwtfbyobbq 04-08-2007 09:07 PM

Just because there's a little fuel being injected, doesn't mean that engine braking doesn't occur.
Quote:

Originally Posted by Wikipedia
Engine braking is the act of using the energy-requiring compression stroke of the internal combustion engine to dissipate energy and slow down a vehicle

As long as the engine is robbing power, instead of providing what's needed at that speed, provided the transmission is in gear, then engine braking occurs. For instance, lets say I'm in fifth, and pass the idle cut while decelerating. There's a small amount of fuel being injected, but because of the pumping losses inherent to gasoline engines, the compression stroke, where pumping losses occur, are what's slowing down the car on the engine side (i.e. by putting it in N, I can avoid engine braking and slow at a lower rate). At least that's how I've always seen it. Not trying to troll or anything, just get terms straightened out and whatnot.

Another nice example imo are diesels. Since there aren't pumping losses of the same magnitude compared to gassers, the force provided by engine braking isn't much at all. So, for big diesels, a separate system is needed to take advantage of engine braking. There's also the closed throttle definition, but this applies as well, since imle, most cars use a separate pathway for idle air flow. :thumbup:


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