Possibility to Reduce Knock Combustion by Egr in the Si Test Engine

The paper presents the results of modelling thermal cycle of internal combustion engine including exhaust gas recirculation. The test engine can not achieve the optimum parameters of work due to occurrence of the knock combustion. The influence of EGR on the limits of the knock occurrence in the engine was studied. It turned out that few percent of exhaust gases in the fresh charge effectively shifts the knock limit to higher ignition advance angles. The values of the limit ignition timing for the test engine was determined in order to avoid combustion knock. Larger share of EGR caused too much slowing the spread of the flame inside the combustion chamber of the test engine. EGR at constant angle of ignition was very effective in limiting the content of NO in the exhaust, but on the other hand it has an adverse effect on the engine parameters. The engine operate with exhaust gas recirculation in order to obtain the possible best parameters the ignition timing should be optimized. However, that with increasing values of the thermodynamic parameters of thermal cycle of engine increased NO content in the exhaust. The paper presents results of modelling thermal cycle of IC engine, including exhaust gas recirculation and knock combustion. The object of researches was the S320ER spark ignition internal combustion engine supplied with petrol. The engine was operated at a constant speed of 1000 rpm. Modelling of the thermal cycle of the test SI engine in the FIRE software was carried out.