Heat release analysis of lean burn catalytic combustion in a two-stroke spark ignition engine

A beat release analysis procedure was developed for a two-stroke spark igni tion engine. The model was used to calculate instantaneous heat release rat es, cumulative heat release and mass fraction burned of base engine and cat alytic engine. The combustion chamber of the catalytic engine was coated wi th a catalyst material by plasma spraying method. The tests were conducted with different air-fuel ratios and heat release analysis was carried out fu r both base and catalyst coated engines. Engine cylinder pressure traces of 2000 continuous cycles were recorded using a pc based data acquisition sys tem. The average of these traces was calculated and used as input to the he at release model. From the heat release rate various combustion characteris tics, such as delay period, start of combustion, end of combustion and comb ustion duration were calculated for the base and catalytic engines. The res ults indicate that the heat release model could be used for the calculation of combustion parameters and accurate enough for the present purpose. The calculated combustion parameters indicate that the catalyst induces pre fla me reactions of fuel air mixture before combustion, which reduces delay per iod and increases the combustion rate. The combustion duration of catalytic engine was reduced by 8 degrees at 0.8 equivalence ratio.