Honda Giken Kogyo Kabushiki Kaisha

Masaki Tsunoda

Tetsu Wada

Hitoshi Suzuki

Shigeaki Kuwabara

Kouji Koishikawa

Sadafumi Shidara

Yoshimi Watanabe

Koji Koishikawa

Shigekazu Sakata

Mitsuharu Tanaka

Hiroki Tawa

Tatsuya Kuroda

Masanori Tsubouchi

Haruo Tsusaka

Hiroyuki Yoshida

Kazuhiro Satou

Hiroyuki Murata

Kouichi Oka

Nobuo Haga

Takao Kashima

Wataru Shimazaki

Mituru Nakamura

A compact and lightweight outboard engine ( ) mounted to a boat stern by a mounting device having a tilt shaft comprises: an engine ( ) including a flywheel ( ) positioned at a lower end portion of a vertically extending crankshaft, and an oil pan positioned below the flywheel ( ). An upper wall of a flywheel chamber ( ) accommodating the flywheel is made up of a bottom wall of a crank chamber made of a crankcase ( ), etc., and a bottom wall ( ) of the crankcase ( ) forming a front portion of the engine body ( ) has a return oil path formed forward of an inner circumferential wall surface ( ) of a circumferential wall ( ) of the flywheel chamber ( ) and having inflow openings ( ) through which lubricant oil flows from the crank chamber. Such outboard engine prevents output loss by preventing or minimizing lubricant oil staying in the crank chamber while the engine is driven in a tilt-up condition.

Outboard engine with improved oil return path

An outboard engine comprises an engine having a crankshaft ( ) extending vertically, a flywheel provided on the crankshaft ( ) below the engine body, an oil pump ( ), and a flywheel chamber ( ) defined by a pump body ( ) of the oil pump ( ) united to coupling walls of the engine body to accommodate the flywheel ; and a mount case ( ) having a support wall for uniting the engine body. The engine body is united with its coupling walls ( ) to the support wall ( ) via an outer circumferential wall ( ) of the pump body ( ) such that the coupling walls ( ), outer circumferential wall ( ) and support wall ( ) overlap in the direction of a rotation axis of the crankshaft ( ). Such outboard engine permits a connecting portion between the engine body and the mount case, which are united together via the oil pump body, to be decreased in size and weight.

Outboard engine

An engine E is received vertically in an engine room,covered by an engine cover,, and a generator,is arranged in a position above a front end of a crankcase,of the engine E and facing an opening,formed at a front of belt covers,. An air flowing from an air intake port,formed at a rear, upper portion of the engine cover,, toward an intake opening,, of an intake silencer,provided at a front, lower end of the engine room,cools the generator,disposed in a path of flow. A part of air in the engine room,is introduced into an interior of the belt covers,through the opening,to be discharged outside from a ventilation port,, and at that time the generator,is cooled by the air which passes through the opening,.

Outboard engine system

A vertical internal combustion engine for an outboard motor having a crankshaft directed substantially in a vertical direction contains a flywheel provided integrally on a lower end of the crankshaft and an oil pan provided under the flywheel. A lubricating oil pump driven by the crankshaft to rotate is disposed under the flywheel, and in the internal combustion engine, the center of gravity is positioned low so that the flywheel can be supported stably and the dischagrability of the lubricating oil pump will be high. Moreover, a pair of balancer shafts connected to the crankshaft to be driven thereby is disposed in parallel with the crankshaft on both sides of the engine cylinders, and balancer shaft lubricating oil passages are provided for lubricating balancer shaft pivot portions.

Vertical internal combustion engine

Integrally fastening a cylinder block,and a crankcase,together by dividing the cylinder block,and the crankcase,at a dividing surface,passing through the center of a crankshaft,vertically arranged and screwing a bolt,inserted from the crankcase,side in the cylinder block,. The bolt,fastening the crankcase,to the cylinder block,is prevented from interfering with a pair of left and right secondary balancer shafts,by supporting both the secondary balancer shafts by the cylinder block,, but not by the crankcase,to increase the degree of freedom of the layout of both the secondary balancer shafts

Balancer shaft support structure in engine and engine hanger device in outboard engine

An outboard motor body case supported on a swivel shaft through a connecting member. The swivel shaft is vertically swingable about a tilting shaft. An engine is mounted at an upper portion of the outboard motor body case, with a crankshaft thereof being oriented vertically, and a flywheel is mounted at a lower end of the crankshaft and disposed between an engine block and the connecting member. A dynamo is mounted within the flywheel, and a starter motor is engaged with a ring gear which is formed around an outer periphery of the flywheel. Thus, since the flywheel having a large weight is mounted at the lower end of the crankshaft, the position of the center of gravity of the outboard motor is lowered. Therefore, it is possible to easily perform a tilting-up about the tilting shaft with a small force. Moreover, since the flywheel is mounted on a power taking-off side of the crankshaft, the torsional vibration of the crankshaft can be reduced.

Outboard motor, and engine thereof

An engine cooling system for an outboard motor includes a thermostat mounted on an upper surface of a cylinder block to open and close a cooling water passage depending on the temperature of cooling water inside the cooling water passage, and a relief valve mounted on an upper portion of a side wall of the cylinder block and located adjacent to the thermostat to open and close the cooling water passage depending on the pressure of cooling water inside the cooling water passage. Since the relief valve is located adjacent to the thermostat, the distance (length of an isolated portion of a drainage passage extending) between the thermostat and the relief valve is very small. In the case where the isolated drainage passage portion has no cooling water flowing therethrough, the pressure of the cooling water inside the cooling water passage rises until the relief valve is open. When the relief valve is open, the cooling water flows into the drainage passage with the result that a sufficient cooling effect can be attained over the entire area of the cooling water passage including the isolated drainage passage portion.

Engine cooling system for outboard engine

A water-cooled 4-stroke cycle internal combustion engine for propelling ships having a cylinder head and a cylinder block. The engine including a plurality of connecting bolts for detachably connecting the cylinder head with the cylinder block arranged around a cylinder with substantially equal distances from a center axis of the cylinder; an exhaust passage formed in the cylinder head positioned on one side of the cylinder, opening on a connecting face to the cylinder block; a cooling water passage disposed around the exhaust passage in the cylinder head, opening on the connecting face; an exhaust passage formed in the cylinder block positioned on the above-mentioned one side of the cylinder, opening on a connecting face to the cylinder head to communicate with the exhaust passage in the cylinder head; a cooling water passage disposed around the exhaust passage in the cylinder block, opening on the connecting face to the cylinder head to communicate with the cooling water passage in the cylinder head; a lubricating oil passage formed in the cylinder head positioned on another side of the cylinder, opening on the connecting face to the cylinder block; and a lubricating oil passage formed in the cylinder block positioned on the above-mentioned another side of the cylinder, opening on the connecting face to the cylinder head to communicate with the lubricating oil passage in the cylinder head.

A flange portion formed on an inner periphery of a flywheel is fitted to an end of a crankshaft. A spline piece is fitted to an inner peripheral surface of the flywheel. The flange portion of the flywheel and a flange portion of the spline piece are commonly fastened to the end of the crankshaft by bolts. An upper end of a driving shaft is spline-fitted at a point into a driving shaft coupled portion of the spline piece which is accommodated in an internal hole in the crankshaft. Thus, in coaxially coupling the flywheel and the driving shaft to the end of the crankshaft, it is possible to make such a coupled area compact and to reduce vibration by an accurate centering thereof.

System for outputting power from a crankshaft

A cylinder block is coupled to a cylinder block/cylinder head coupling surface of a cylinder head by ten bolts which are disposed to surround outer peripheries of combustion chambers. In order to enhance sealability of an opening of a cooling water passage defined radially outside the bolts as viewed from the combustion chambers, the cylinder block and the cylinder head are further fastened to each other by a bolt disposed in the vicinity of the opening. Thus, the fastening force of the cylinder block/cylinder head coupling surface can be increased to increase the degree of freedom in design of the opening of the cooling water passage defined in the coupling surface.

Engine for outboard engine system

Outboard motor and engine thereof

A flange portion formed on an inner periphery of a flywheel is facet-fitted to an end of a crankshaft. A spline piece is facet-fitted to an inner peripheral surface of the flywheel. The flange portion of the flywheel and a flange portion of the spline piece are commonly fastened to the end of the crankshaft by bolts. An upper end of a driving shaft is spline-fitted at a point into a driving shaft coupled portion of the spline piece which is accommodated in an internal hole in the crankshaft. Thus, in coaxially coupling the flywheel and the driving shaft to the end of the crankshaft, it is possible to make such a coupled area compact and to reduce vibration by an accurate centering thereof.

Power output system for an outboard engine

A four-cycle engine for an outboard motor includes an upwardly extending breather chamber which communicates with a projecting portion provided at a lower part of a crankcase and with an induction system via a PCV passage for returning a blow-by gas to intake manifolds. With this arrangement, it becomes possible to remove oil components from the blow-by gas within the PCV passage and hence to return the substantially oil-free blow-by gas to the intake manifolds.

Four-cycle engine for outboard motor

In an outboard marine engine having a vertically oriented crankshaft, a bracket for supporting an AC generator is provided with a pair of cantilever arms for supporting a pivoted portion and a fixed portion of the AC generator, and a belt cover for the engine is partly supported by extensions of these cantilever arms. The bracket is typically mounted to a portion of the crankcase defining a corner between a vertical end surface and a horizontal top surface. By thus securing the belt cover to the bracket for securing the AC generator, it is possible to firmly support the belt cover and prevent undesirable rattling or vibration of the belt cover because the bracket is given with a sufficient rigidity from the need to firmly support the electric generator. Therefore, the firm support of the belt cover can be accomplished without any substantial cost increase.

Growing community of inventors

Wako, Japan

Masaki Tsunoda