Abstract: An intake system for a multiple-cylinder engine a plurality of primary discrete intake passages and a plurality of secondary discrete intake passages. Each pair of primary discrete intake passage and the secondary discrete intake passage communicate with one of the cylinders. Both the primary and secondary discrete intake passages are straight and the primary discrete intake passage is provided with a primary valve member which is provided with an opening and is selectively positioned in a closed position where the primary valve member limits the effective cross-sectional area of the primary discrete intake passage to the cross-sectional area of the opening and in an open position where the primary valve member wide opens the primary intake passage.

Abstract: An internal combustion engine comprises reinforcing means secured to an edge portion of a lower opening of the cylinder block at a peripheral edge portion thereof. The reinforcing member has a plate-like shape, has connecting parts extending laterally with respect to the direction of the engine for connecting the facing edge portions of the lower opening of the cylinder block and is formed with openings for passage of oil at the front portion thereof and is secured to an oil pan at the lower surface of its front portion. The rear portion of said reinforcing means forms a part of an outer lower wall of a crank case containing a crank shaft and bifurcates into an upper branch extending backwardly and upwardly and a lower branch extending backwardly and downwardly. The upper branch has an end portion for connection with the cylinder block and the lower branch has an end portion for connection with a transmission case.