Abstract: An internal combustion engine generally utilizes a conventional four stroke process including an intake stroke, compression stroke, expansion stroke, and exhaust stroke and in addition to this four stroke process, adds a secondary process having two additional strokes for scavenging the combustion chamber with fresh air. This two stroke scavenging process employs a fresh air intake stroke and a fresh air exhaust stroke to exhaust any remaining burnt and unburnt gases from the combustion chamber.

Abstract: An improved exhaust gas cleaning system for a multi-cylinder internal combustion engine having an exhaust system with exhaust ports opening into a plurality of combustion chambers. A secondary air supplying system is in communication with the exhaust system for supplying secondary air to the exhaust system. A plurality of reed valve devices are interposed in the secondary air supplying system and are operated to open and close in response to pulsations of exhaust gas developed in the exhaust system during engine operation for controlling supply of secondary air to the respective exhaust ports independently of each other.

Abstract: There is disclosed a cover structure in a power transmission device comprising a casing having an open side, a driver shaft rotatably supported by the casing, a driven shaft rotatably supported by the casing and drivable by the driver shaft, a power transmission mechanism housed in the casing for transmitting rotative power from the driver shaft to the driven shaft, a starter mechanism housed in the casing and engageable with the driver shaft for starting an engine, and cover means covering the open side of the casing. The cover means comprises a plurality of cover members, a cover member which supports the starter mechanism being securely coupled to the casing, the remaining cover member or members being coupled to the casing through a resilient member or members.

Abstract: A cooler for a belt type transmission in a power unit for vehicles in which a transmission casing is provided on one side of an engine body, and a belt type transmission composed of a drive pulley connected with the crankshaft of the engine body, a driven pulley connected with an output shaft and an endless transmitting belt engaged between the pulleys is contained in a transmitting chamber in the transmission casing, wherein an air intake passage and a rear air exhaust passage are respectively provided front and rear portions of the transmission casing, an intermediate air exhaust passage is provided in the intermediate between the front portion and the rear portion of the transmission casing, so that the inlet of the intermediate air exhaust passage is opened in the zone that the endless transmitting belt is isolated from the driven pulley at the tension side of the endless transmitting belt in the transmission chamber; and further wherein a suction port is opened in the outer wall of the transmission casin

Abstract: A system for cooling the engine compartment and for providing clean air to the air cleaner of a motorized cycle having a body cover, including an engine fan, a fan cover extending between the fan and a head cover surrounding the cylinder head, and a vent hole in the shroud formed by the fan cover and the head cover directing the air flow induced by the fan, after it has been used to cool the cylinder head, into the engine compartment defined by the body cover and towards the air cleaner intake port.

Abstract: A cooling fan is provided on at least one of the drive pulley and the driven pulley which are drivingly coupled together by means of a belt. The casing in which the pulleys and the belt are accommodated is provided with air inlet port means and air outlet port means. Rotation of the cooling fan in unison with rotation of the pulley provided with the cooling fan causes fresh air to be forcibly sucked into the casing through the air inlet port means, and discharged to the outside through the air outlet port means after cooling the pulleys and the belt. The air inlet port means and the air outlet port means are arranged or constructed so as to prevent intrusion of dust, mud, water, etc. into the casing. Further provided are means for enhancing the efficiency of cooling the driven pulley by the fresh air drawn in as well as means for radiating heat generated within the casing through the casing walls.

Abstract: An improved internal combustion engine for use with motorcycles including an intake system, an exhaust system, a starting aid such as a choke valve in the intake system for expediting the engine starting, and an exhaust gas cleaning device adapted to supply secondary air to the exhaust system for cleaning the exhaust gas flowing therethrough. The exhaust gas cleaning device comprises a secondary-air supply passage communicated with the exhaust system, a secondary-air control valve gear disposed in the intermediate part of the secondary-air supply passage and adapted to regulate the flow rate of the secondary air flowing through the supply passage, and a controller connected to the valve gear and adapted to close the same on detecting the operation of the starting aid and a vehicle speed below a set value.

Abstract: A cooling fan is provided on at least one of the drive pulley and the driven pulley on which the drive belt is wound. A substantially closed casing in which the pulleys and the belt are accommodated has its interior partitioned in two chambers. With rotation of the fan, the air inside the casing is circulated within the casing where one of the chambers acts as a going passage and the other as a return passage, respectively, to thereby cool the pulleys and the belt. The two chambers are communicated with each other by communication means which are arranged at the pulleys and adapted to allow smooth movement of the air through the pulleys. Further provided are means for enhancing the efficiency of cooling the driven pulley by the circulating air and means for radiating heat generated within the casing through the casing walls.

Abstract: Herein disclosed is an exhaust gas recirculation system for an internal combustion engine, in which system communication is provided between an exhaust passage and an intake passage by way of an exhaust gas recirculation passage so that the exhaust gas in the exhaust passage is partially recirculated into the intake passage by the intake vacuum prevailing in the intake passage.

Abstract: Herein disclosed is a secondary air supply control device for use with an apparatus for purifying an exhaust gas of an internal combustion engine. In the exhaust gas purifying apparatus, a secondary air supply system is made to communicate with the exhaust system of the internal combustion engine so that secondary air may be supplied during the running operation of the internal combustion engine to said exhaust system thereby to oxidize and clear the unburned noxious content of said exhaust system. The secondary air supply control device comprises a vacuum-operated secondary air control valve which is disposed midway of said secondary air supply system for controlling the flow rate of the secondary air to be supplied to said exhaust system; and means for controlling said vacuum-operated secondary air control valve during the deceleration and the choking operation at the start of said engine so that the supply of the secondary air to said exhaust system is interrupted.

Abstract: An exhaust gas cleaning device for internal combustion engines, comprising an exhaust system having an exhaust port, a secondary air supply system having an upstream secondary air supply passage communicating with the atmosphere and a downstream secondary air supply passage communicating with the exhaust port for supplying the exhaust system with secondary air, and a reed valve device disposed in the secondary air supply system and adapted to open and close in response to the pulsations of the exhaust gas pressure in the exhaust system. The reed valve device includes a valve housing constituted by a housing structure formed on the cylinder head cover of the engine and a cover member secured to the housing structure, the cover member having a plurality of projections projecting inwardly from the inner surface thereof. The reed valve device also includes a reed valve member clampingly held between the upper surface of the housing structure and the projections of the cover member.

Abstract: An exhaust gas cleaning system for an internal combustion engine having an exhaust system leading to an exhaust port of an engine body. The exhaust gas cleaning system comprises a TWC catalyst disposed in the exhaust system for simultaneously cleaning HC, CO and NO.sub.X in exhaust gas flowing through the exhaust system. A secondary-air supply passage is connected to the exhaust system on the upstream side of the TWC catalyst and coupled to the atmosphere.

Abstract: An exhaust gas cleaning system for an internal combustion engine is provided which has an exhaust system including a TWC catalyst. The exhaust gas cleaning system comprises a secondary air supply passage coupled to the exhaust system on the upstream side of the ternary catalyst for supplying secondary air to the exhaust system. A secondary air control valve is positioned in the secondary air supply passage for regulating the flow of secondary air therethrough. The secondary air control valve comprises a unitary valve casing, a valve passage in the valve casing coupled to the secondary air supply passage, and first and second control valves for separately opening and closing the valve passages. The first control valve is closed when the engine is decelerating and the second control valve is closed when the engine is accelerating or operating at high speed, thereby maintaining the TWC catalyst as a reducing atmosphere.

Abstract: An exhaust gas cleaning device of an internal combustion engine wherein a secondary-air supply passage is connected to an exhaust system of the engine and a reed valve means is provided in the intermediate part of the secondary-air supply passage for opening in response to the pulsation pressure of the exhaust gas in the exhaust system to supply secondary air for cleaning exhaust gas to an exhaust passage and burn the unburnt components present in the exhaust passage thereby to clean exhaust gas. A desired amount of secondary air is supplied to each of a plurality of exhaust systems so that the exhaust gas cleaning efficiency as well as the reliability and durability of the reed valve means are improved and moreover a good external appearance is obtained.

Abstract: A motorcycle having an internal combustion engine mounted on a main frame and including suction and exhaust systems, an exhaust gas cleaning means adapted to supply secondary air to the exhaust system for cleaning an exhaust gas flowing therethrough, a carburetor provided in the suction system and provided with a throttle valve therein, and a throttle opener provided on the carburetor and adapted to open the throttle valve slightly while the internal combustion engine is decelerated. A secondary air supply passage is connected to the exhaust system, and a flow rate of the secondary air flowing through the passage is controlled by a secondary air control valve. When a vehicle speed of the motorcycle has decreased to a level not higher than a predetermined level, the secondary air control valve is closed to stop supplying the secondary air to the exhaust system, and the operation of the throttle opener is rendered ineffective simultaneously. This prevents the temperature of the exhaust gas from increasing.

Abstract: An improvement of an exhaust gas cleaning system for an internal combustion engine which is provided with a secondary air feed system connected to an exhaust port and a reed valve device opened on an exhaust pulsation pressure arising in the exhaust port to feed secondary air to the exhaust port.The secondry air feed system has an upstream side secondary air passage through to the atmosphere and a downstream side secondary air passage formed on a thick wall zone of the internal combustion engine proper and connected through to the exhaust port. The reed valve device has a valve casing installed on the circumference of the engine proper, an inflow port connected to the upstream side secondary air passage, and an efflux port connected to the downstream side secondary air passage. The valve casing is partitioned internally into an upstream chamber provided adjacently to the engine proper and a downstream chamber provided on a side away from the engine proper across the upstream chamber.

Abstract: An exhaust gas cleaning device of an internal combustion engine, comprising a secondary-air supply system connected to exhaust ports to supply the secondary air for cooling the exhaust gas, and reed valve devices installed in the secondary-air supply system and adapted to be opened and closed by the pulsating pressure generated in the exhaust ports when the engine is in operation. The reed valve devices are mounted on the side surface of the cylinder block, each of which has a reed valve chamber and a reed valve that divides the reed valve chamber into an upstream chamber and a downstream chamber and that is adapted to be opened and closed by the pulsating exhaust gas. The upstream chamber is communicated with the open air via a secondary-air intake pipe, and the downstream chamber is connected to the exhaust port via a secondary-air supply passage.

Abstract: An exhaust gas cleaning system for an internal combustion engine including two cylinders arranged in V-shape and an exhaust system having exhaust ports. A secondary air supplying system is connected to the exhaust system for supply of secondary air. Reed valve devices responsive to an exhaust gas pulsation pressure are incorporated in the secondary air supplying system and are opened and closed under the action of exhaust gas pulsation developing during engine operation. The reed valve devices are disposed in a space defined between the two cylinders. The reed valve devices are connected to the exhaust ports through respective secondary air supplying pipes which form a part of the secondary air supplying system. The secondary air supplying pipes are wound so as to surround the respective cylinders.

Abstract: An exhaust gas cleaning system for an internal combustion engine having a cylinder head with a plurality of exhaust valve ports therein associated with respective exhaust valves and an exhaust passage for discharge of exhaust gases to an exhaust system. The exhaust passage is constituted by a manifold exhaust port which is connected to the exhaust system and a plurality of branch ports which branch from the manifold exhaust port and communicate with respective exhaust valve ports. A secondary air passage is directly connected to the respective branch exhaust ports for supplying secondary air thereto in immediate proximity to the exhaust valves. Each secondary air passage is composed of a manifold secondary air passage opening externally of the cylinder head and branch secondary air passages branching from the manifold secondary air passage and communicating with the branch exhaust ports.

Abstract: A catalytic converter having two spaced catalyst elements is positioned between a front muffler and a rear muffler. Chrome plating of the mufflers does not adversely affect performance of the catalyst elements because welding of the mufflers to opposite ends of the catalytic converter is accomplished after the chrome plating step. Masking of the joinder areas before plating avoids blow holes at the welds, and silver paint is later applied to the areas which were masked. The catalytic converter is constructed by simultaneously pushing the two catalyst elements and flanged sleeves into opposite ends of the catalyst casing, using tapered guide rings and flanged pusher bars to squeeze peripheral cushions into place within the catalyst casing and around each of the catalyst elements. Welding electrodes are employed in combination with the flanged pusher bars to spot weld the catalyst casing to the flanged sleeves.