A New Technique to Detect and Control Knock Damage

High speed knock leads in particular circumstances to serious damage. Several mechanisms may be the source of deteriorations:

• preignition usually due to the presence of deposits.
• overheating ruining immediatly the engine when a “runaway knock” occurs.
• gradual decay of the combustion chamber depending on the design of the chamber and on the quality of materials.

Analysing the temperature of the exhaust gases and establishing special testing techniques make possible the quantitative study of knock damage. The paper gives examples of matching of fuels and engines at knock damage limit.