Originally Posted by
peterrr
I have done some thinking and figured out how anti knock works:
The burning of gasoline is an exponential accelerating process. When you have an ideal mix the speed is greatest. When you miss the ideal mix by 10 % the reaction will slow down by 10 %. The reaction is regulated by condensing fuel onto the cylinder head. Here you see that you get a regulating loop over reaction, pressure, condensation, reaction speed, etc. The gain in this loop is only 1. Normally you will get a linear rise in pressure, but if you enter the condensing zone while the piston goes up you will get a quadratic curve. The substances creating knocking control convert a vast majority of the fuel into large molecules. After the detonation a lot of gooey fuel has to be burned off the cylinder head, with air with little oxigen in it. Result: soot ,unburnt HC.:mad: Adding water vapour would make the engine run cooler and the burn off easier
