Mitsubishi Heavy Industries Limited

Hiroyoshi Kouchi

Shogo Nakamura

Kazuyuki Kobayashi

Yuji Nagase

Shigeichi Okada

Isao Katayama

Shin Mizukami

Kazayuki Kobayashi

The object of this invention is to improve the safety of an engine by preventing fuel which might splash out of the fuel inlet on top of the fuel tank or drip onto the tank during fueling from coming in contact with the hot cylinder or any electrical components. Another object of this invention is to prevent vibration of the fuel tank and the noise which such vibration would cause. The fuel tank according to this invention has an upper and a lower portions joined by a flange, both of which are made from a resin material. The upper portion has a trapezoidal depression in its center which surrounds the fuel inlet and slopes downward toward one side of the tank. The overall surface of the upper portion is convex and also slopes downward toward the same side of the tank. A number of grooves on either side of the central depression run in the same direction and open onto the same side of the tank. The two halves of the tank are welded at the web of a ribbed flange which extends around the entire periphery.

Fuel tank and general purpose engine equipped with the same

A fuel gauge unit for a fuel tank which, when the gauge unit is attached to the fuel tank, is fixed in its rotational angle in a simple fashion, and in which the fuel scale is simple and easy to inspect visually. An indicator is provided which moves back and forth in a horizontal plane when a bearing connected to a float rotates. The position of the indicator corresponds to a fuel scale, so that the quantity of fuel in the fuel tank can be determined by inspecting the gauge. On the top of the gauge unit is a protruding rectangular portion with a transparent window. This protruding rectangular portion engages in a hole in the cover plate attached to the fuel tank. The protruding rectangular portion and its hole may have a rectangular or oblong surface which serves as a rotational position lock for the gauge unit.

Fuel gauge unit for a fuel tank

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.

In a mounting configuration for an exhaust pipe cover of an engine in which a muffler is affixed to an outlet flange of an exhaust pipe whose inlet flange is connected to an exhaust outlet of a cylinder head of the engine, the exhaust pipe cover which shields the exhaust pipe is affixed with a bottom of the muffler to the outlet flange of the exhaust pipe. An upper flange of the exhaust pipe cover is affixed to both the bottom of the muffler and the outlet flange of the exhaust pipe, and a front portion of the exhaust pipe cover extends downward from the upper flange in such a way as to cover the exhaust pipe.

Mounting configuration for the exhaust pipe cover of an engine

A configuration for mounting a fuel line on an engine which reduces the number of parts needed to mount the fuel lines and the fuel cock, reduces the number of assembly and mounting processes, and improves both the handling qualities and the safety of the engine at a low cost. In this fuel line configuration for a single-cylinder multi-purpose engine having a fan cover and a front cover on the front of the engine, a fuel tank on top of the engine is connected to the carburetor by a fuel line with a fuel cock on it. Semicircular grooves are provided in the fan cover and front cover, and the fuel line is engaged in a channel formed by the two grooves and thereby immobilized. The fuel cock, which is attached to the front end of the fuel line, is mounted to the front cover.

Mounting configuration for an engine fuel line

A general purpose air-cooled, four-cycle engine in which a first ball bearing supporting the output shaft of the crankshaft is larger than the second ball supporting the other end of the crankshaft, and the first bearing has an external diameter which is approximately equal to or greater than the distance from the crankshaft to the camshaft. The camshaft driven by the crankshaft is supported by sliding bearings. The governor which controls the rotation of the engine and which is driven by the rotation of the crankshaft is enclosed in the crankcase on the same end as the cooling fan, which is the end opposite the output end of the crankshaft. This invention fulfills the demand for a smaller crankcase; does not make use of special bearings; and achieves a greater bearing capacity through the use of large-diameter standard-precision ball bearings. In addition, it simplifies the required processing and allows the assembly process to be automated.

General-purpose air-cooled four-cycle engine

Air guide casing for air-cooled engine

A cooling fan made of synthetic resin for an air-cooled engine which is fixedly secured to a side of the body of a flywheel includes a plurality of cooling fins formed along a circumferential direction thereof, and a circular reinforcement rib projecting axially from the periphery of a backboard, thereby reducing deformation of the fan during running of the engine and preventing deformation of the fan during transportation, without significantly increasing the weight of the fan.

Cooling fan for an air-cooled engine

The objective of this invention is to solve two sorts of problems in an engine using a chain transmission scheme with the camshaft as the output shaft. One set of problems results from the stretching of the chain. The other concerns lining up the crankshaft and camshaft during assembly. With this invention, power is transmitted from the crankshaft to the camshaft by means of a silent chain. The silent chain is tensioned before use to suppress its initial tendency to stretch. The chain is installed so that the slack in the chain is 1 to 2% looser than its theoretically calculated distance value between the crankshaft and the camshaft. (A chain tensioner is not used.) One or several marks are provided on the opposed surfaces of the aforesaid silent chain and the two sprockets to help match the positions of the crankshaft and camshaft.

Air-cooled engine for general use

The object of this invention is to provide an operating panel for an engine which would require a smaller number of parts for throttle mechanism, operation panel and the related components. It also requires fewer assembly processes, and improves the outer appearance of the engine. In this operating panel, a cut-off switch to stop the engine is installed in a custom-designed cover, which has a cut-off terminal electrically isolated from a ground, and can electrically ground the cut-off terminal by making a contact with the throttle lever electrically grounded. The operational panel is easily fixed to the fan cover by engaging a protrusion and a hole. The operational panel has a groove to run a fuel pipe.

Growing community of inventors

Nagoya, Japan

Hiroyoshi Kouchi