Kubota Corporation

Kentaro Shiraishi

Hiroaki Isoshima

Hiroshi Manabe

Shinji Kishi

Naotaro Nagai

Yutaka Noyori

A blow-by gas return device includes: a gas path which is configured to introduce a blow-by gas generated in a crankcase into an intake system through an inside of a head cover, a pressure control valve and a blow-by pipe; and an orifice provided to the gas path, the orifice mounted on a wall portion of an intake manifold on a cylinder head side. A passage for a blow-by gas is formed in the wall portion on the cylinder head side, and the orifice is formed on a joint pipe mounted on the passage for the blow-by gas for communicably connecting the blow-by pipe with the passage for the blow-by gas.

Blow-by gas return device

In an engine head cover, an upper portion of a partition plate, which partitions an inside of a head coverinto upper and lower portions, forms a blowby gas passage W having an inletand an outletcommunicating with an intake path. A PCV valvedisposed on the outletside, a filterdisposed on the inletside, and a labyrinthdisposed between the PCV valveand the filterare provided. A recovery holewhich causes a flowdown of trapped oil is formed at a portion on a downstream side of the filterin a flow direction of a blowby gas in the blowby gas passage W and on a lower side of the labyrinthand the pressure regulating valve

Engine head cover

An intake device of a multicylinder engine includes an intake manifold having a collector portion extending in a front-rear direction, an intake air introducing portion disposed at a center in the front-rear direction of the collector portion, and branch portions led out from front and rear end portions and of the collector portion. The branch portions are connected to an intake port of a cylinder head. A throttle body is disposed at an upper portion of the intake air introducing portion, and has a butterfly-type throttle valve, a valve shaft of which is oriented in the front-rear direction. A blow-by gas inlet portion is provided to the intake air introducing portionof the intake manifold, and is disposed on a side to which a lower end portion of the half-open throttle valve is directed and on a downstream side of the lower end portion.

Intake device of a vertical multicylinder engine

The invention provides a blow-by gas recirculating apparatus for a crankcase with enhanced ventilation efficiency. A fresh air introducing chamber is remote from a head cover. An upstream intake passage of a throttle valve is communicated with the fresh air introducing chamber, and the fresh air introducing chamber is communicated with a crankcase through a crankcase communication throttle hole which is opened in the crankcase. Fresh air in the upstream intake passage of the throttle valve is introduced into the crankcase sequentially through a fresh air introducing passage, the fresh air introducing chamber, and the throttle hole, without being short-circuited to a PCV valve. In a reverse flow from the crankcase to the upstream intake passage of the throttle valve, a gas in the crankcase reversely flows into the upstream intake passage sequentially through the throttle hole, the fresh air introducing chamber, and the fresh air introducing passage.

Growing community of inventors

Sakai, Japan

Kentaro Shiraishi