The investigation of the effects of premixed MTBE charge on HCCDI-DI engine performance and exhaust emissions

In this study, the effects of premixed methyl tert-butyl ether (MTBE) charge on the engine performance and exhaust emissions were experimentally investigated in a single-cylinder, four stroke, HCCI-DI diesel engine. The experiments were conducted at the maximum torque speed of 2200 rpm under full load (16 Nm) and half load (8 Nm) operating conditions. Premixed MTBE fuel was injected into the intake manifold of the engine with a low-pressure injection system and controlled by a programmable electronic control unit. In the experiments, the maximum torque that the engine gives under conventional diesel operation was decreased between 10 % - 50 % at an interval of 10%. Same torque value was obtained with MTBE fuel injection. In the experiments, the variations of specific fuel consumption, thermal efficiency and exhaust emissions (THC, CO, NOx and soot) were investigated for each premixed MTBE ratio. As a result of the experimental studies, the specific fuel consumption (SFC) decreased up to 10 % premixed MTBE ratio and no significant change was observed with the increase of premixed MTBE ratio at full load. At half load, the SFC was showed a continuous increase with the increase of premixed MTBE ratio. At full load, thermal efficiency increased by 27,16 %, at half load, firstly decreased and then showed a horizontal process. Depending on the increase of premixed MTBE ratio, HC emissions increased by 53,5% at full load and showed a continuous slope up to 243,97% increase at half-load. At full load tests, CO emissions increased up to 20% premixed MTBE ratio and then decreased. CO emissions increased continuously at half load. NOx emissions increased by 55,56 % at full load. No significant change was observed at half load operating conditions. It was seen that soot emissions decreased at partial HCCI operation depending on premixed MTBE charge at each engine load.