HCCI Engine Operation with Acetylene the Fuel

The homogeneous charge compression ignition (HCCI) engines emit low levels of smoke and NOx emissions. However, control of ignition, which is mainly controlled by fuel composition, the equivalence ratio and the thermodynamic state of the mixture, is a problem. In this work, acetylene was as the fuel for operating a compression ignition engine in the HCCI mode at different outputs. The results of thermal efficiency and emissions have been compared with base diesel operation in the (compression ignition) CI mode. The relatively low self ignition temperature, wide flammability limits and gaseous nature were the reasons for selecting this fuel. Charge temperature was varied from 40 to 110°C. Thermal efficiencies were almost equal to that of CI engine operation at the correct intake charge temperature. NO levels never exceeded 20 ppm and smoke levels were always lower than 0.1 BSU. HC emissions were higher and were sensitive to charge temperature and output. However, investigations are required to further extend the operating range of acetylene HCCI operation. On the whole this work demonstrates that acetylene can be considered as a HCCI engine fuel.