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Kedar Malwadkar
Kedar Malwadkar • Jul 5, 2012

what is detonation?

What is meant by the term 'detonation' in the context of mechanical engineering? Can someone explain this term, its use as to where, why and how? Please reply.
white_hat • Jul 5, 2012
In a Si engine the position of spark plug is important.This decides the flame speed and controls the direction of shock wave produced during combustion.
In case of knocking or detonation the fuel air mixture is not ignited by the spark produced by spark plug.Ignition can be caused by carbon deposition inside the cylinder head or by the residue after the previous combustion.This produces a shock wave which is not controlled and hits the cylinder walls and creates the mechanical pinging sound.
Detonation is also called as knock,knocking spark knock,pinging. Meaning of detonation is the action of causing of a bomb or explosive device due to explode. when the unburnt fuel in the engine cylinder attains SIT(self ignition temperature),then the fuel is burned itself with a sound of explosive resulting in a detonation or knocking.
ISHAN TOPRE • Jul 7, 2012
One way to avoid detonation or engine knock is to use high octane rating fuel. They are available under fancy names as "Super gasoline", "Extra Premium" etc. Practically, not much gain you will make by using them. However, most of the vehicles in market are designed NOT to use them. Means you can use simple gasoline and have a good ride. Yet, the companies (read fuel companies) are shrewdly branding them.

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