nosles on engines i do not understand

[West]

I just saw that Renault vid... man I miss those V10s

Well here's a bonus V12 engine sound vid... well sort of

http://www.youtube.com/watch?v=j5zH7wBZgaI

[Birel99]

a few questions...
under braking or closed throttle situations thier seems to be VERY little fuel injected into the body. does it just look like thier is NO fuel or is their actualy very little. the flames coming out the exhaust is unburnt fuel ( i think) so why is it emphasized on downshifts and why isnt that fuel being burnt?

[pyry]

isnt it pretty obvious why you dont want fuel burning in the engine under engine braking?

[Birel99]

so how do they stop the fuel from igniting in the cylinder?

[manchild]

isnt it pretty obvious why you dont want fuel burning in the engine under engine braking?

If they didn't want fuel to burn in cylinders under braking than they'd set ECU not to inject fuel under braking. Engine must work properly even under braking because if fuel wasn't burnt engine would stall.

[zac510]

You can inject no fuel into the engine at all when the engine is decelerating but they usually inject a tiny little bit so that there is no hesitation when the driver jumps on the accelerator again.
I imagine this would be particularly important in an f1 car to avoid unsettling the car while it is in an uncomfortable position, for example the middle of a high speed turn

[NickT]

The main reason they continue to pump fuel into the engine is not to over brake the driven wheels and cause premature lockup under heavy braking. When an engine is turning with no fuel it becomes a very power hungry compressor, left un fed (with fuel) it will lock the rear wheels

[zac510]

Yeah from 19000rpm that would certainly be the case!