Abstract: A two-stroke internal combustion engine which is capable of minimizing the quantity of blow-by or the quantity of air-fuel mixture to be discharged without being utilized for the combustion, of improving the fuel consumption and power of the engine, of reducing the content of poisonous components in the exhaust gas, and of reducing the manufacturing cost, without extensively altering the conventional engine. A through-hole or a communication groove is provided at the skirt portion of a piston to thereby enabling a scavenging inlet port to be communicated with the crank chamber. In the descending stroke, combustion exhaust gas from the combustion actuating chamber is enabled to be introduced, via a scavenging outlet port provided at a downstream end of the scavenging passageway, into the scavenging passageway while closing the scavenging inlet port at the skirt portion of the piston.

Abstract: An air-preintroduction type two-stroke internal combustion engine which is capable of minimizing the quantity of blow-by, thus making it possible to improve the fuel consumption and to reduce the content of poisonous components in the exhaust gas, and is also capable of reasonably and compactly arranging the peripheral components of engine, thereby making it possible to reduce the number of parts, to lighten the weight thereof, to save the manufacturing cost thereof, and to simplify the working and assembling thereof. Specifically, this internal combustion engine is characterized in that an air inlet passageway for introducing air into the scavenging passageways is provided inside a wall portion of the cylinder.

Abstract: A two-cycle internal combustion engine which is capable of inhibiting air-fuel mixture from being mixed with the air introduced in advance into the combustion actuating chamber during the scavenging period, thereby realizing a complete lamellar scavenging.

Abstract: An air-preintroduction type, two-stroke internal combustion engine which is capable of minimizing the quantity of blow-by, thus making it possible to improve the fuel consumption and to reduce the content of poisonous components in the exhaust gases, and is also capable of reasonably and compactly arranging the peripheral components of the engine, thereby making it possible to reduce the number of parts, to lighten the weight thereof, to save the manufacturing cost thereof, and to simplify the working and assembling thereof. The engine is characterized in that an air inlet passageway for introducing air into the scavenging passageways of the engine is provided at a mating face between the cylinder and the crankcase of the engine.

Abstract: A two-stroke internal combustion engine is disclosed capable of reducing the number of pieces constituting the main body, thereby making it possible to reduce the number of parts such as assembling bolts and hence to reduce the manufacturing cost as well as the weight thereof while ensuring the rigidness of the main body. The main body of the engine includes a cylinder portion in which a piston is adapted to be fittingly inserted and a crankcase portion in which a crank shaft is rotatably supported via a bearing wherein the crankcase portion is constructed such that it is split into an upper and a lower crankcase portion by a horizontal plane which passes through a central axial line of the crankshaft, where the upper crankcase portion is integrated with the cylinder portion, thus forming an integral cylinder-case, and a fan case base is formed integral with the lower crankcase portion.

Abstract: An air-preintroduction type two-stroke internal combustion engine which is capable of minimizing the quantity of blow-by, thus making it possible to improve the fuel consumption and to reduce the content of poisonous components in the exhaust gas, and is also capable of reasonably and compactly arranging the peripheral components of engine, thereby making it possible to reduce the number of parts, to lighten the weight thereof, to save the manufacturing cost thereof, and to simplify the working and assembling thereof. Specifically, this internal combustion engine is characterized in that an air inlet passageway for introducing air into the scavenging passageways is provided inside a wall portion of the cylinder.

Abstract: A two-cycle internal combustion engine which is capable of inhibiting air-fuel mixture from being mixed with the air introduced in advance into the combustion actuating chamber during the scavenging period, thereby realizing a complete lamellar scavenging.

Abstract: A two-stroke internal combustion engine which is capable of minimizing the quantity of blow-by or the quantity of air-fuel mixture to be discharged without being utilized for the combustion, of improving the fuel consumption and power of the engine, of reducing the content of poisonous components in the exhaust gas, and of reducing the manufacturing cost, without extensively altering the conventional engine. A through-hole or a communication groove is provided at the skirt portion of a piston to thereby enabling a scavenging inlet port to be communicated with the crank chamber. In the descending stroke, combustion exhaust gas from the combustion actuating chamber is enabled to be introduced, via a scavenging outlet port provided at a downstream end of the scavenging passageway, into the scavenging passageway while closing the scavenging inlet port at the skirt portion of the piston.

Abstract: A two-stroke internal combustion engine has an air passageway for introducing air into a scavenging passageway communicating a combustion/actuating chamber disposed above a piston with a crankcase and an air-fuel supply passageway for introducing an air-fuel mixture from a carburetor into the combustion/actuating chamber. On the descending stroke of the piston, an exhaust port opens before a scavenging port formed at an upper end of the scavenging passageway opens, and an air-fuel mixture-feeding port disposed at a downstream end of the air-fuel supply passageway is opened a moment after the scavenging port is opened. Thus, air is introduced into the combustion/actuating chamber prior to the introduction of the air-fuel mixture.

Abstract: A two-stroke internal combustion engine which is capable of reducing the number of pieces constituting the main body, thereby making it possible to reduce the number of parts such as assembling bolts and hence to reduce the manufacturing cost as well as the weight thereof while ensuring the rigidness of the main body. The main body of engine essentially consists of a cylinder portion in which a piston is adapted to be fittingly inserted; and a crankcase portion in which a crank shaft is rotatably supported via a bearing; wherein the crankcase portion is constructed such that it is split into an upper crankcase portion and a lower crankcase portion by a horizontal plane which passes through a central axial line of the crankshaft, where the upper crankcase portion is integrated with the cylinder portion, thus forming an integral cylinder-case, and a fan case base is formed integral with the lower crankcase portion.

Abstract: A two-stroke cycle internal combustion engine has a quaternary Schnürle-type scavenging system that is configured such that the capacity of a pair of second scavenging passageways are made larger than the capacity of a pair of first scavenging passageways, so that during the descending stroke of the piston, air is allowed to be introduced into the combustion actuating chamber from the second scavenging passageways prior to the introduction of the air-fuel mixture and at the same time, a relatively large quantity of air is allowed to be introduced into the combustion actuating chamber from the first scavenging passageways over a longer period of time as compared with the period of time in which air is introduced from the second scavenging passageways.

Abstract: An air-preintroduction type, two-stroke internal combustion engine which is capable of minimizing the quantity of blow-by, thus making it possible to improve the fuel consumption and to reduce the content of poisonous components in the exhaust gases, and is also capable of reasonably and compactly arranging the peripheral components of the engine, thereby making it possible to reduce the number of parts, to lighten the weight thereof, to save the manufacturing cost thereof, and to simplify the working and assembling thereof. The engine is characterized in that an air inlet passageway for introducing air into the scavenging passageways of the engine is provided at a mating face between the cylinder and the crankcase of the engine.

Abstract: The four-stroke cycle internal combustion engine for portable working machines, which employs a toothed belt in the power transmission mechanism thereof, is disclosed. There is provided an OHC type four-stroke cycle internal combustion engine including a power transmission mechanism disposed vertically along a cylinder portion for transmitting the rotation of a crankshaft to a camshaft, wherein the power transmission mechanism comprises intermediate transmission members linked to the camshaft through a toothed belt and a rotation speed transmission member for reducing the rotation speed from the crankshaft and for transmitting it to the intermediate transmission members.

Abstract: A four-stroke cycle internal combustion engine comprises a connecting rod which has an oil dipper at a big-end thereof, a crankcase, a partition wall which surrounds the connecting rod to provide a separation between the crankcase and an oil reservoir and an outer wall which is outward of and surrounds the partition wall and is connected to the partition wall at upper ends thereof so as to define the oil reservoir below the crankcase. A slit is formed in the partition wall below the connecting rod to allow the oil dipper to protrude into and be withdrawn from the oil reservoir to splash oil in the oil reservoir for lubrication by the oil dipper through a swinging motion of the connecting rod. The depth of the oil reservoir is shallower at least in a part of an outer edge area thereof than that below the oil dipper so that a tip of the oil dipper reaches the oil level even when the oil flows into the outer edge area of the oil reservoir.

Abstract: A structural member of a furnace body for a shaft furnace includes a metallic structural member (1) having a flow path for a coolant therein; inner furnace refractories (2) provided on a cooling surface of the metallic structural member; metallic supporting members (3) for connecting which support the inner furnace refractories on the metallic structural member; and heat insulating members (4) arranged between the metallic supporting members and the inner furnace refractories.

Abstract: A four-stroke cycle internal combustion engine, having a crankcase. A connecting rod is provided in the crankcase. An inner wall extends to surround all sides and the bottom of the connecting rod. An outer wall extends to surround the inner wall. The upper ends of the outer wall are connected to the inner wall to form an oil reservoir under the crankcase and oil recess areas on both sides of the crankcase therebetween. An oil dipper for splattering the oil contained in the oil reservoir is provided at the big end of the connecting rod. A slit is formed at a bottom of the inner wall for allowing the oil dipper to go though to make contact with the oil.

Abstract: A four-stroke cycle internal combustion engine allowing simplified assembly, high productivity, and still high precision in assembly is made up of a crankshaft; a camshaft; a gear train for transmitting the rotation of the crankshaft to the camshaft; and a housing block. The housing block includes a cylinder portion with the gear train disposed in a longitudinal direction along the cylinder portion. The housing block further includes a bearing portion for supporting the crankshaft, an upper outer wall portion extending vertically downward from the cylinder portion to the bearing portion and a longitudinally oriented gear case for housing the gear train. The housing block is divided into a cylinder block main body part and a cylinder block lower part at the bearing portion of the crankshaft. The cylinder block body portion includes an integrally formed cylinder portion, upper outer wall portion and gear case.

Abstract: A four-stroke internal combustion engine in accordance with the present invention comprises a piston, a valve chamber, a crankcase, an oil chamber separated from the crankcase, and an oil mist feeding passage extending from the oil chamber to the crank case via the valve chamber for supplying oil mist in the oil chamber. The oil mist feeding passage has a first passage extending from the oil chamber to the valve chamber, a second passage extending from the valve chamber to the crankcase, and a third passage extending from the crankcase to the first passage. The first passage has a first opening directed toward the oil chamber. The second passage has a second opening directed toward the crankcase located at a point where it can be closed by the piston when it travels downwardly. The third passage has a third opening directed toward the crankcase located at a point below a bottom dead center of the piston.

Abstract: An OHC type four-stroke cycle internal combustion engine comprises a crankshaft, a camshaft, a camshaft bearing for supporting the camshaft, a cam chamber for accommodating the camshaft, a gear train for transmitting the rotation of the crankshaft to the camshaft, a gear chamber for accommodating the gear train, a crankcase communicating with the cam chamber via the gear chamber, an inlet port, and a piston. The camshaft has a camshaft through hole which communicates with the cam chamber at one end and opens toward its circumferential surface supported by the camshaft bearing at the other end. The camshaft bearing has a camshaft bearing through hole which communicates with the camshaft through hole at one end and communicates with the inlet port at the other end.

Abstract: An internal combustion engine includes: a cylinder block having a connecting surface formed at a lower portion thereof and a skirt portion extending outwardly from the connecting surface; a crankcase having a connecting surface for contacting the connecting surface of the cylinder block and a bore for inserting the skirt portion therewithin; and, a gasket interposed between the connecting surfaces of the crankcase and the connecting surface of the cylinder block when assembled such that the gasket has a bore formed at the central portion thereof. A pair of detent portions are formed at the outer periphery of the skirt portion with each of the detent portion being different in shape from each other. A pair of recess portions, corresponding to the detent portions, are formed at each of the bores of the crankcase and the gasket.