Quote:
Originally Posted by Cycle
As for his stating that most of the fuel burning takes place after TDC, he's yet again correct. Most of the fuel burning (and hence expansion) takes place after TDC. If it didn't, there'd be no available power.
|
This has been proven wrong before, but here goes:
When fuel gets burned it produces a lot of pressurised exhaust gas and heat.
The pressure is what drives the piston down in the expansion phase.
It will do that for all of the expansion phase.
The pressure rises sharply when the ignition takes place just before TDC, and that will indeed slow down the engine a little bit.
But
the pressure is still there when the piston moves past TDC, and will stay there until it gets released in the exhaust phase.
Ideally you'd burn all the fuel the instant the engine is a TDC so none of it hinders the compression phase and all of it aids the expansion phase.
The heat just increases the pressure, it also heats up the pistons and cylinder walls so that the fuel won't condensate on them once the engine is at operating temperature.
__________________
2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gmeter or 0.13 Mmile.
For confirmation go to people just like you.
For education go to people unlike yourself.