Modelling of a Spark Ignition Engine for Power-Heat Production Optimization

Spark ignition gas engine is more and more used in order to produce electricity and heat simultaneously. The engine crankshaft drives a synchronous electric generator. The thermal power output is recovered from the engine coolant system and exhaust gas, and is used to produce generally hot water for heating system. In order to have a better adequacy between supply (production of the engine) and user demand, good knowledge of the engine and implemented phenomena are necessary. A generic methodology is proposed to simulate the stationary state response of a SI engine. The engine simulation is based on a one zone thermodynamic model, which characterizes each phase of the engine cycle to predict energy performances: exergy efficiency as high as 0.70 is attainable