DETONATION

Detonation -: Detonation is generally caused by fuel with low octane rating - is the tendency for the fuel to pre - ignite or auto ignite in a engine's combustion chamber. The auto-ignition propagates a high pressure wave through fuel air mixture, giving a voilent blow to the walls of cylinder. A fuel having higher self ignition temperature detonates less.

                         The effect of detonation may be anywhere from arbitrary to serve. prolonged and intense knocking can break the piston or the engine , through it is can also endure this slight issue for thousand miles. 

           Detonation is mostly caused by the use of low- grade engine fuel and it is resulting deterioration of your engine's parts. The shape, size and spark location and geometry of the design all help determine where these detonation are likely to occur. An over-heated spark plug tip can also cause pre-ignition 

Detonation in petrol engines can be reduced by the addition of a small amount of lead ethide or ethyl fluid to the fuel. This is the known as doping. 

                           The knocking tendency in a petrol engines can be prevented by ensuring that the charge away from the spark plug has low density , low temperature,  long ignition delay, and rich mixture. It is also decreased by reducing compression ratio, and increasing the engine speed with fixed octane rating fuel. However knocking in the petrol engines is increased by increase in cooling water temperature and supercharging .

                The knocking tendency in diesel engines can be prevented by reducing the delay period, increasing the compression ratio , inlet pressure og air and injection pressure.