| 摘要 |
A two-stroke internal combustion engine comprises a piston 19 reciprocable in a cylinder 20 having a piston-controlled exhaust port 23 allowing communication with an exhaust passage 24. Movable shutter means 1 are provided to vary the effective area of the exhaust port 23 cyclically in a timed relationship to the reciprocal motion of the piston 19 and a compression ratio variation mechanism 41, which is additional to and separate from the movable shutter means 1, varies the compression ratio of the cylinder 20. Sensors (12,14,34, figs.5,7) measure one or more operating parameters of the engine and generate control signals corresponding thereto and a control unit (11) processes the signals to control independently the motion of the movable shutter means 1 and the compression ratio variation mechanism 41. The invention enables homogeneous charge compression ignition (HCCI) combustion over a large area of the operating map, giving improved emission reduction and fuel efficiency compared with the four-stroke gasoline equivalent. |
