Exergy analysis of an HCCI engine

Homogeneous Charge Compression Ignition (HCCI) engines are known to have a number of advantages such as high thermal efficiency, very low NOx and PM emissions and low heat losses compared to conventional spark plug ignition (SI) and compression ignition (CI) engines. Therefore, in HCCI engines, the air / fuel mixture formed outside the cylinder is taken into the cylinder almost homogeneously and compressed, and when the temperature of the air / fuel mixture reaches the ignition temperature, combustion starts simultaneously in all parts of the cylinder. However, the simultaneous combustion of the mixture simultaneously in the whole cylinder results in a very high increase in the pressure, especially at high engine loads, which causes a knock. At low engine loads, there is an inability to ignite due to the extremely poor mixture. Because of these problems, HCCI engines are not yet commercially available directly. In this study, HCCI engine was examined by exergy method. In experiments performed at 8 different engine speeds, the percentage of fuel exergy; On the other hand, in this study, it is obtained that the average exhaust energy is 10.1%, cooling water exergy is 5.8%, radiation exergy is 6.8%, effective power exergy is 17.2% and exergy loss is 16.7%. The change in energy percentages, in the experiments performed at 8 different engine speeds, is the average percentage of engine speed of 1500 1 / min compared to the fuel energy; 19.3% of the exhaust heat was found to be 36.4% of cooling water and 50.9% of the radiation heat. The maximum exhaust heat value was 19.39 kW at 1500 rpm and the highest effective power was 23.67 kW at 1500 rpm. It has been found that the percentage exergy loss in the lost exergy is caused by the exhaust exergy with an average of 11.9%. The average cooling water exergy in the lost exergy was 6.9% and the radiation exergy was 7.9%. In this regard, various literature researches and previous studies in this field have been discussed with their general details