Intake system for multiple-cylinder engine.

摘要

An intake system for a multiple-cylinder engine has a plurality of discrete intake passages which are substantially equal to each other in length and are connected to the respective cylinders at their downstream ends. The upstream ends of the discrete intake passages are merged into an integrated chamber, and an upstream side intake passage communicates the integrated chamber with the atmosphere. The integrated chamber has an upstream side end face and a downstream side end face, and the cross-sectional area of the integrated chamber increases from the upstream side end face to the downstream side end face, the upstream side intake passage having opening into the integrated portion in the upstream side end face, and the discrete intake passages respectively having openings into the integrated chamber in the downstream side end face. The area of the upstream side and downstream side end faces of the integrated chamber S0 and S1, the sum of the areas of the openings of the discrete intake passages into the integrated chamber SN and the distance H between the upstream side and downstream side end faces of the integrated chamber satisfy the following formulae S0>0.25 x SN H/ 2ROOT S1>0.7 x (S1/S0) T