| 摘要 |
<p>A method for supplying EGR in a multi-cylinder internal combustion engine is described. Each cylinder of the engine has at least one intake valve and one exhaust valve operating according to the valve opening events of a four stroke engine cycle. The method comprises the steps of selectively interchanging in timing relative to the engine strokes the opening events of the intake and exhaust valves of one or more cylinders of the engine when EGR is required so that the exhaust valve is opened during a downward stroke of the cylinder drawing exhaust gases from the exhaust system of the engine into the cylinder and the intake valve is opened during a upward stroke of the cylinder discharging exhaust gases from the cylinder into the intake system of the engine. The cylinder (EGR cylinder) thereby operates as a positive displacement exhaust gas charger with two gas exchange strokes and two non gas exchange strokes during the four stroke engine cycle delivering exhaust gases for mixing with the intake air supplied to the remaining cylinders (power cylinders) of the engine. Fuel may be injected into the EGR cylinder for pre-conditioning of the fuel within the hot exhaust gases in the EGR cylinder, and the EGR gases and pre-conditioned fuel may be subsequently mixed with the intake air supplied to the power cylinders of the engine for combustion within the power cylinders.</p> |
