掺氢对自由活塞发动机性能及排放的影响研究

A miniature free piston linear engine fueled by methane was designed and manufactured. Effects of hydrogen addition on the performance and emission characteristics of the FPLE were studied. The experimental results showed that the FPLE performance is improved significantly with the hydrogen addition. Compared with that of pure fuel condition, the indicated power and indicated thermal efficiency are increased by 60.1% and 59.2% respectively. The optimal performance is achieved with the hydrogen volume concentration of 4%. However, the engine performance cannot be further improved when the hydrogen volume concentration further increases since more hydrogen addition can cause advanced combustion to occur. Moreover, the lean operating range of the engine is significantly extended and the engine operating stability is also improved. The high-speed color images showed the flame is lighter and less yellow compared with that of pure methane addition, indicating that the hydrogen addition to the main fuel have significant impacts on suppressing the soot formation.