| 摘要 |
<p>An intake system for a multi-cylinder internal combustion engine in which each cylinder has at least one intake valve (10) and first and second parallel intake passages supplying separate streams through the intake valve to the combustion chamber of the cylinder. The volume ratio and the velocity ratio between the first and second streams through the intake valve (10) during a substantial part of the intake period of each engine cycle are non-zero and constant for a wide range of engine speeds and loads in order to achieve charge stratification, the volume and flow velocity ratios being set by providing a perforated flow restriction (30) in the first intake passage. The size and density of the perforations (32) are selected such that the high velocity small jets induced at the perforations (32) in the first stream are diffused to a lower uniform velocity within the first intake passage before the two streams enter the combustion chamber through the intake valve (10). In the invention, the total volume of the first and second intake passages downstream of the points of minimum through-flow cross section in the two passages is less than half the swept volume of each engine cylinder.</p> |
