Performance of Two/Four-Stroke Gasoline HCCI Engine With Electromagnetic Valve Train

摘要

Comparison of net thermal efficiency and emission in two- and four-stroke gasoline HCCI engines has been carried out for various valve-timings as negative valve overlap and exhaust valve double opening. The valve timings could easily be converted from one mode to another by configuring schedule of electromagnetic valve train. Extension of operable torque with high thermal efficiency had been expected in two-stroke HCCI operation, however friction and supercharger loss curtailed about half of the gain in indicated thermal efficiency. In four-stroke operation modes, exhaust valve double opening ("reinduction" or "rebreathing") showed the best net thermal efficiency and emission; however the extension of high load limit could not be considerably achieved.