Application of HCCI Engine in Motorcycle for Emission Reduction and Energy Saving

ABSTRACT

The exhaust emission of motorcycle engine is a big problem in Asia countries due to the large number of motorcycles. This study developed a homogeneous charge compression ignition (HCCI) engine for motorcycle application with high-operating efficiency and low exhaust emissions. The development was carried out on a 150 cc spark-ignition (SI) engine with an increased compression ratio to enhance compression temperature. Dimethyl ether (DME) was selected as the main fuel for HCCI operation due to the low self-ignition temperature. Gasoline was used as an additional fuel to adjust the ignitibility of the dual fuel mixture. The dual fuel and exhaust gas recirculation (EGR) were incorporated to expand the engine operating range. Experiments of varying DME flow rates, EGR ratios, and gasoline flow rates were performed to observe HCCI operating characteristics and to identify methods for controlling HCCI combustion. And then, the engine could be operated at speeds ranging from 2000 to 4000 rpm and BMEP (Brake Mean Effective Pressure) ranging from 1.56 to 4.86 bar. These operating points were found to have lower brake specific fuel consumption and lower CO and NO emissions as compared with the original SI engine. A range-extended electric motorcycle (REEM) was built from a conventional motorcycle by using the proposed HCCI engine as a range extender. The HCCI engine was operated at 3500 rpm with very stable and high efficiency to match the REEM. The fuel economy of the proposed motorcycle is 75.62 km L^–1, a 132% improvement compared with the original motorcycle. The control of switch from SI to HCCI will be the future work.