| 摘要 |
<p>A method and a system are described for operating a four-stroke reciprocating internal combustion engine, the system having exhaust and intake valve timings such that the exhaust valve is closed at or after 30{ after tdc, and the intake valve is opened at or after 30{ after tdc and closed at or after 70{ after bdc. The system further includes an intake port throttle, eg a perforated plate, in the intake port for segregating a predetermined volume of air in the intake port immediately upstream of the intake valve such that, when the intake valve opens, the air pressure in the segregated volume is substantially equal to the gas pressure in the cylinder and that, during the remaining intake stroke, air enters the cylinder substantially by bulk expansion of the air in the segregated volume from an initial pressure when the intake valve opens to a lower pressure at the end of the intake stroke.</p> |
