| 摘要 |
<p>A two-stroke internal combustion engine includes a combustion chamber (25), a piston (21) operable to pump air unmixed with fuel into the combustion chamber, a fuel injector (31) for injecting fuel unmixed with air directly into the combustion chamber, an ignition system (35) and a spark plug (37) for igniting the fuel charge in the combustion chamber, and an exhaust manifold (41) communicating with the combustion chamber. The engine is operable to produce a thermal reaction in the exhaust gas so as to reduce exhaust emissions by injecting the fuel at an injection timing which is retarded from the optimum timing and in an amount to provide an air-fuel ratio richer than the optimum for minimum emissions in an engine without a thermal reaction in the exhaust system, and providing an ignition timing which is retarded from minimum advance for best torque.</p> |
