Controlled Combustion

Controlled Combustion Points : controlled combustion, phases of combustion, problems in internal combustion engines, ic, engine, auto diesel Normal gasoline combustion occurs when the spark plug ignites the fuel and burning process smoothly through the fuel mixture. Maximum cylinder pressure should be produced a few degrees or crank rotation after piston TDC on the power stroke.

In A, a spark at the spark plug start: the fuel burning. A small ball of flame forms around the tip of the plug. The piston is moving up in the cylinder, compression the fuel mixture.

In B, the flame spreads faster and moves about half way through the mixture. Generally, the flame is moving evenly through the fuel mixture. The piston is nearing TDC, causing increased pressure.

In C, the piston reaches TDC. The flame picks up more speed. In D, the flame shoots out to consume the rest of the fuel in the chamber.

Combustion is complete with the piston only a short distance down the cylinder. Normal combustion only takes about 3/1000 of a second. This is much slower than an explosion (dynamite explodes in about 1/50000 of a second). Under some undesirable conditions however, gasoline can be made to burn too quickly, making part of combustion like an explosion.