Abstract: A blow-by gas ventilation system for a crankcase of an engine includes an improved construction for distributing blow-by gases more evenly between multiple cylinders. The engine has an air intake device that includes a plurality of air delivery conduits for the cylinders and a plenum chamber housing disposed upstream of the air delivery conduits. The ventilation system comprises a blow-by gas conduit that couples the crankcase with the plenum chamber housing. The plenum chamber housing includes an opening to which the blow-by gas conduit is connected. A baffle is disposed in front of the opening within the plenum chamber housing so as to divide the blow-by gases equally for the respective cylinders.

Abstract: An intake manifold is provided in which blow-by gas is distributed uniformly and readily to the cylinders of an engine. The intake manifold 10 is made of aluminum and has a blow-by gas passage 14 formed integral with a collector 11 as ridged on the collector 11 and located adjacent to the proximal ends of intake manifolds 12a,12b, 12c, and 12d, which are mounted vertically of the collector 11, to extend at a right angle to the axes of the intake manifolds 12. Mounting rings 20 are provided next to the ridged block-by gas passage 14 for accepting the proximal ends of the intake tubes 12.