| 摘要 |
<p>An intake manifold system (10) is described for a multi-cylinder four stroke spark-ignition internal combustion engine (12). Each cylinder has at least one intake port (20), each intake port (20) being connected at one end to the combustion chamber by at least one intake valve (14) and at the other end to a first intake duct (22) that is connected to a first plenum (24) common to the first intake ducts (22) of other engine cylinders. Each intake port (20) is also supplied by a second intake duct (32) the through-flow cross section of which is 25% to 45% of the maximum effective through-flow cross section of the open intake valve. The geometry of the intake port (20) and of the discharge end of the second intake duct (32) is such that the gas that enters from one side of the intake port (20), is constrained by solid boundary walls to perform a single U-turn by flowing around the intake valve stem (14) while adhering to the walls of the intake port (20) and enters the first intake duct (22) via the other side of the intake port (20), the gas thereby scavenging the closed end of the intake port (20) and displacing substantially all the gases previously present therein into the first intake duct (22).</p> |
