Super-knock suppression RCM experiments

The research of normal combustion, knock and super-knock in highly boosted gasoline engine could be conducted on a RCM platform associated with optical methods to obtain the pressure traces and images of the whole combustion process.

The RCM results show that the combustion process of normal combustion could be summarized as “spark ignition followed by flame propagation”, while that of knock is “spark ignition followed by deflagration which could induce end-gas auto-ignition followed by pressure oscillation”.

Furthermore, the detailed combustion process of super-knock includes several steps :

(1) Pre-ignition before spark ignition;

(2) Flame propagation induced by pre-ignition;

(3) Auto-ignition induced by hot-spot in the end-gas unburned mixture which results in rapid heat release and pressure rise;

(4) Shock wave induced by the strong end-gas auto-ignition;

(5) Detonation induced by shock wave and its interaction effects with the wall, the reaction front or other shock waves;

(6) Extremely high pressure oscillation induced by detonation wave propagation.

Therefore, suppressing super-knock directly could be realized by suppressing detonation, even if pre-ignition has already existed.