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 of1000 rpm. Modelling of the thermal cycle of the test SI engine in the FIRE software was carried out

Influence of exhaust gas recirculation on the ignition delay in supercharged compression ignition test engine

The results of analysis of thermal cycle of the test engine are presented in the paper. The study focused on determining the ignition delay in compression ignition engine. The correlations available in literature, Hardenberg and Hase, Wolfer and Watson and Assanis were used to determine ignition delay. With the increase of the EGR the ignition delay has increased. It turned out that very often it is necessary to determine own ignition delay correlation

: Interpretation of measurement results of flow velocity in the ICE combustion chamber

W opracowaniu przedstawiono interpretację wyników pomiaru prędkości przepływu ładunku w komorze spalania tłokowego silnika spalinowego. Analizie poddano wpływ metody opracowania wyników pomiaru prędkości przepływu na uzyskane wyniki parametrów opisu pola prędkości w komorze spalania silnika tłokowego.The paper presents measurement results of flow field of fresh charge in the combustion chamber of the internal combustion engine. Possibilities of interpretation results of flow velocity measurement in combustion chamber of internal combustion engine are presented in the paper. The data handling method of flow velocity measurement result influence on obtained turbulence field in combustion chamber parameters are analyzed. The results of research show that non-repeatability of flow velocity in the combustion chamber have influence on description of turbulence parameters

Cmbustion of mixture of diesel fuel with gasoline in a compression ignition engine

Paper presents results of experimental investigation of combustion process of diesel-gasoline blend in compression ignition direct injection engine. The researches were conducted for constant load of engine at constant rotational speed. Operating parameters of engine powered with diesel-gasoline blend were at the same level as for engine powered by pure diesel fuel. The preliminary study was conducted using CFD modelling. Based on encouraging modelling results preliminary experimental research was carried out. It turned out that it is possible to co-burning diesel with the gasoline as a blend. A mixture of 20, 40 and 60% of gasoline with diesel was used. It was concluded that an increase in gasoline fraction in blend causes delay of start of the combustion process. The homogeneity of the fuel-air mixture was improved due to longer ignition delay, which is accompanied by higher values of pressure rise rate. With 20 and 40% of gasoline fraction causes higher peak pressure compared to reference fuel-burning ware obtained. Up to 40% of gasoline fraction, the BSFC was kept at the same level as for reference fuel. It was observed that with the increase in gasoline fraction up to 40% NOx emission increased as well. Based on the carried out tests it can be stated that it is possible to co-burn gasoline with diesel in a compression ignition engine while maintaining the invariable engine operating parameters and exhaust emissions