Yamaha Hatsudoki Kabushiki Kaisha

Yamaha Kogyo Hatsudoki Kabushiki Kaisha

Yoshiharu Isaka

Kiyohiko Oguri

Yukiharu Hosoi

Masahiro Ito

Takao Kawai

Mutsuaki Miyaki

Yoshimi Tachibana

Nozomu Kishira

Tadakazu Ishibashi

A number of embodiments of induction systems for three-intake-valve-per-cylinder internal combustion engines, wherein the intake valves and the flow passages serving them are disposed so as to generate a tumble motion in the inducted intake charge. A number of embodiments of control valves are provided for redirecting the flow and increasing the tumble action under low-speed, low-load conditions. The control valve in each embodiment is journaled in the cylinder head at a position outwardly of the fasteners which secure the cylinder head to the cylinder block, but still quite close to the valve seats so as to provide maximum turbulence generation.

Tumble valve for multi-valve engine

A number of embodiments of single intake valve per cylinder engine wherein the induction passage is provided with a control valve for generating a tumble action in the intake passage when the engine is operating at speeds other than high speed high load. The arrangements are designed so as to promote a stratification in the combustion chamber under some running conditions and the intake passage is disposed at an angle to a plane containing the cylinder bore axis.

Tumble valve arrangement for engine

A number of embodiments of induction system for internal combustion engines employing multiple intake valves. The induction systems are designed so as to provide substantially unrestricted charging and axial flow into the cylinder bore when running under high-speed, high-load conditions. A control valve is provided which changes the effective configuration of the induction passages so as to provide a slant tumble action under lower speed and load conditions. Various arrangements are disclosed for altering the amount of slant action and providing slant actions in opposite or the same direction. In addition, a single control valve element is provided for achieving this effect in a three poppet valve per cylinder engine.

Induction system for engine

A number of embodiments of induction systems for internal combustion engines wherein a control valve arrangement is provided in the induction passage for selectively generating either or both of tumble and/or swirl to the intake charge in response to varying running conditions. Various types of control valve arrangements are disclosed as are systems for cooling the control valves and augmenting the flow pattern caused by the control valve.

Tumble control valve for intake port

Several embodiments of induction systems for internal combustion engines wherein the effective shape of the intake passage may be changed during engine running conditions to achieve turbulence of the desired type in the combustion chamber and improve volumetric efficiency at low and mid range performance and provide a substantially uninterrupted introduction of charge under high speed running so as to improve the performance throughout the entire engine load and speed ranges. Also, a control valve arrangement is provided in the exhaust system for improving performance under low engine speeds and low engine loads.

A number of embodiments of intake passages for internal combustion engines wherein it is possible to obtain a tumble and tumble and swirl action or both under some running conditions and substantially unrestricted flow under high speed conditions so as to improve volumetric efficiency while, at the same time, increasing turbulence under the conditions when the flow pattern is altered. The flow pattern is controlled by a rectifier plate which extends through at least one of the intake passages and divides it into two flow areas, one of which is closed by a control valve which engages the rectifier plate in its flow controlling position so as to provide a stop for the control valve. The control valve is configured and oriented so as to provide substantially unrestricted flow paths in each of its positions. Embodiments incorporating carbureted and fuel injected engines are depicted.

Intake air control system for the engine

A power unit for a small vehicle such as a motorcycle embodying a two-cycle, crankcase compression, air/fuel injected engine. Fuel and air pumps are driven by the engine and are positioned inwardly of the outer extremity of a plane defined by the outer face of the clutch of the engine transmission assembly and the adjacent side of the engine. A two speed drive is provided for the air pump of the fuel/air injection system so as to operate the air pump at a higher speed ratio during cranking than during running so as to insure adequate air supply for the engine even during starting.

Pump drive for engine

Several embodiments of snowmobiles driven by an engine and variable belt transmission mechanism wherein the variable belt transmission has its input shaft journaled for rotation in the crankcase of the engine and driven from the engine crankshaft through a gear reduction so that the transmission loads are not carried by the crankshaft and wherein the crankshaft torsional vibrations are not transmitted to the transmission input shaft.

V belt type automatic transmission system

Several embodiments of air cooled rotary lawn mowers wherein the mower is provided with a cooling shroud for directing cooling air downwardly across the engine. The cooling shroud defines an air inlet that is spaced from the discharge chute so that grass clippings are not likely to enter it. The engine is laid out so that the center of gravity of the mower is disposed rearwardly of the axis of the cutting blade for facilitating turning.

Vertical engine for walk behind lawn mower

A rotary lawn mower having an air-cooled single cylinder four-cycle internal combustion engine for powering its cutting blade. The engine is air cooled and is disposed so that its exhaust port lies above the intake port and the carburetor is positioned above a raised portion of the scroll part of the lawn mower housing for good cooling of the exhaust port without heating of the carburetor. A valve operating mechanism is disclosed including a pair of push rods that are supported on the exhaust port side of the engine and which are surrounded by a mass of cylinder head and cylinder for assisting in heat dissipation.

Vertical engine for walk-behind lawn mower

A vertical shaft internal combustion engine particularly adapted for powering a rotary type lawn mower. The engine is provided with a baffled crankcase so as to minimize the adverse effects of oil 'sloshing' within the crankcase while, at the same time, permitting flow between the baffles. In addition, an oil slinger arrangement is incorporated that is also baffled so as to reduce frothing in the crankcase to reduce aeration of the oil in the crankcase and also to direct the oil flow from the slinger.

Lubricating system for vertical shaft engine

A lawn mower or other similar walk behind type of implement that is designed to be operated in a normally erect position and which is tilted to its side for servicing. An engine is provided for the lawn mower having an output shaft rotatable about a vertically extending axis. The engine includes a lubricating system incorporating a crankcase in which the engine output shaft rotates and a crankcase ventilating system. The crankcase ventilating system is designed so as to prevent lubricant from flowing into the induction system when the engine is tilted on its side.

Two embodiments of motorcycle engine mounting and exhaust arrangements wherein the exhaust pipes of the rear bank of a V type engine are adapted to pass between the forward pivot point of the rear suspension arm and a recess formed in the crankcase transmission assembly of the engine. In one embodiment, the recess is defined by a single rearwardly extending engine mounting projection. In the other embodiment, the recess is defined between a pair of spaced rearwardly extending mounting projections. In the embodiment wherein only one mounting projection is employed, an arrangement is provided so as to insure balance of the loading on the frame from the single engine mount.

Exhaust system for motorcycles

An exhaust and rear suspension system for a motorcycle that permits a compact, easily serviced arrangement. The engine is of the V type and has a bank of cylinders with rearwardly facing exhaust ports. The rear wheel is suspended by a pair of spaced apart trailing arms having independent forward pivot axes that define a gap therebetween through which exhaust pipes extend from the rearwardly facing exhaust ports.

Growing community of inventors

Iwata, Japan

Yoshiharu Isaka