Effect of Squish and Quench in Detonation

Effect of Squish and Quench in Detonation Points : effect of squish and quench in detonation, the factors that effect the spark knock, the factors that effect the detonation, problems in internal combustion engines, ic, engine, auto diesel The shape of the combustion chamber, including those portions of the piston and valves, which acts as chamber wall surfaces, is most important from the point of view of detonation. The piston shown in the following diagram is called a squish piston because the charge is squeezed radically inward near top dead center.

With the same inlet valve the combustion time is about the same as with the flattop piston, since the spark advance required is about the same, but the tendency to detonate is appreciably less.

The usual explanation offered for the fact that arrangements involving squish reduce the detonation tendency is based on the assumption of a cooling effect. It is pointed out, near the end of flame travel, the end gas is located in a thin space where it makes excellent contact with cylinder walls, which are at low temperature. Because of this theory the thin space in the combustion chambers of this type is often called the quench area. Effect of Turbulence The shape of the combustion chamber has an important bearing upon the detonation of the engine. A swirl (turbulence) combustion chamber causes air-fuel mixture to swirl or spin as it enters from the intake port. This causes the air and fuel to mix into a finer mist and burns better and this reduce the chances of detonation.