Overall Engine Performance

This chapter provides overall view of the performance of the internal combustion engine. It uses the information about friction, heat transfer, and combustion to explain and discuss the influence of various factors, such as engine size, piston speed, load, compression ratio, and ignition timing. The chapter introduces performance maps for various representative spark ignition and compression ignition engines. It illustrates the effects of engine speed on the power and coolant load of an automotive spark-ignition engine at full load and the effect of the air–fuel ratio on brake-specific fuel consumption of a spark-ignition engine at a constant load. For spark-ignition gasoline engines, the timing parameter is the spark timing, and for diesel engines the timing parameter is the fuel injection timing. The chapter also discusses the effect of compression ratio on the brake-specific fuel consumption of a diesel engine.