Mitsubishi Heavy Industries Limited

Shigeichi Okada

Kazuyuki Kobayashi

Shogo Nakamura

Hiroyoshi Kouchi

Isao Katayama

In order to supply a sufficient quantity of lubricating oil to the entire valve operating mechanism, we designed a lubrication device for an overhead valve engine. A first breather passage goes from the valve operating mechanism chamber to the crankcase, passing through the cylinder head and cylinder. The first breather passage opens in the vicinity of the spring retainer for the intake valve on the surface of the cylinder head which faces the valve operating mechanism chamber for the valve operating mechanism. The opening of the first passage and the vicinity of the exhaust valve are connected by a second breather passage. This second passage comprises a groove formed by cutting in the valve operating mechanism chamber surface of the cylinder head, and a tunnel formed between an oil guide wall which goes up from the valve operating mechanism chamber surface of the cylinder head and the peripheral wall of the head. One end of this groove connects to the opening of the first breather passage.

Structure of overhead-valve internal combustion engine and manufacturing method for the same

To simplify the assembling process to mount a valve operating mechanism on a cylinder head, one intake valve and one exhaust valve are mounted on the cylinder head symmetrically with respect to the axis of a cylinder shaft. A rocker arm supporting base which supports rocker arms is fixed to the top of the cylinder head. Rocker arm shafts are supported by the base. The central portions of the rocker arms engage with the rocker arm shafts in such a way that the arms are free to swing. Push rods and the intake and exhaust valves are engaged with the ends of the arms. The valve operating mechanism is enclosed in a head cover which is fixed to the top surface of the cylinder head. This engine is distinguished by having the mounting surface for the rocker arm supporting base, on which the rocker shafts are mounted, and the surface on which the head cover sits be virtually coplanar. This makes it possible to machine the two surfaces at the same time. In order to supply a sufficient quantity of lubricating oil to the entire valve operating mechanism, a particularly designed lubrication device is provided.

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Aichi-ken, Japan

Shigeichi Okada