Abstract
The combined effect of compression ratio, engine speed, intake air temperature, nitrogen diluent an spark-timing on the lean misfire limit is investigated experimentally for a CFR engine with propane as a fuel. The misfire limit is defined as the point where 5 to 8 cycles out of 1,000 consecutive cycles have firing pressure traces equal to the motoring presssure trace.
A balance between energy produced in the entrained volume of the developing flame and the energy diffused to unburnt gas is proposed as a model for the flame initiation. The initial conditions for the turbulent flame extinction process are obtained from a k∊ model which includes the effect of compressibility