Effect of cooling water flow direction on performance of an acetylene fuelled HCCI engine

This paper deals with experimental investigations carried out on an acetylene-fuelled engine operated in homogeneous charge compression ignition (HCCI) mode to study effect of cooling water flow direction on intake charge temperature and heating requirements, and performance of the engine. In this study, in a possible load range, experiments are conducted on a single-cylinder, water-cooled, acetylene fuelled HCCI mode with conventional and reverse cooling water flow directions using different intake charge temperatures at different loads. At every load condition, best possible intake charge temperature is determined based on brake thermal efficiency. Results obtained in two cases of cooling water flow directions of HCCI mode are compared with those of conventional diesel CI mode. From the results, it is found that, reverse cooling water flow direction shows about 14 to 50% reduction in external intake charge heating at different load conditions as compared to conventional cooling water flow direction. There is an improvement in brake thermal efficiency by about 5 to 10% at different load conditions. Nitric oxide (NO) and smoke emissions are very low in both cases. However, hydrocarbon (HC) and carbon monoxide (CO) levels are higher than conventional CI mode in both the cases.