Abstract: A portable generator in whose casing are housed an engine and a generator directly connected to and driven by the engine. A single cooling fan is provided at the connecting portion of a crankshaft in said engine and a revolving shaft in said generator to produce a unidirectional cooling air flowing from the generator side through the outside and inside of the generator to the engine side, as well as air intake and exit ports are provided in said casing side walls respectively in the vicinity of the side surface opposite to the engine of said generator and opposite to the generator of said engine, thus resulting in a high cooling efficiency of and an enhanced soundproof effect on the engine and generator as well as in a more compact generating system.

Abstract: An engine balancing system for a single-cylinder engine including a single primary balancer and a counterbalancer for reducing rotational vibration, wherein the single primary balancer has an axis of rotation disposed parallel to a crank shaft of the engine and is driven at the same velocity as the crank shaft in a direction opposite to the direction of rotation of the crank shaft. A cylinder of the engine has a center line which deviates from the center axis of the crank shaft and is displaced toward the single primary balancer.

Abstract: An engine cooling system for field machinery such as tractors equipped with a lawnmower. A cooling system is arranged with a radiator placed in a slanting position in the upper rear part of engine within engine room and with the lower end of the radiator placed on the engine side. A cooling fan is so mounted that the cooling air induced by the radiator cooling fan passes through upward from under the radiator. The cooling fan is preferably placed downstream in the cooling air flow of the radiator, that means, above the radiator. Further it is desirable that a cooling air passage is so arranged that the cooling air which has passed through the radiator may blow out of air outlet through the vicinity of the engine, and that the outgoing air flow is so directed that hay blown up by field machinery's travels and operations be kept away from cooling air inlet, for instance, being directed forward ahead of the engine.

Abstract: This disclosure relates to cooling apparatus for a water-cooled internal combustion engine. The apparatus comprises a centrifugal fan driven by the engine when running, said fan having an intake air port and a discharge air opening. A rotary screen is also driven by the engine, the screen being disposed over the intake air port of the fan and substantially preventing debris from entering the intake air port. The apparatus further includes a cooling radiator, and a spiral-shaped duct connecting the radiator with the fan discharge air opening. Further separating means is provided in the duct for removing debris from the air, the separating means being at an intermediate part or at an end part of the duct.

Abstract: An internal combustion engine of the spark ignition type developing a maximum output power at about 8000 rpm includes at least two ignition plugs for each cylinder and projections formed on the inner wall surface of a cylinder head for producing a squishy current. The engine also includes an ignition device including a delay circuit for delaying the ignition time in the high-speed rotation range, to thereby provide improvements in the output power and fuel consumption rate over the entire rotation range.

Abstract: An engine stopping device for rendering an internal combustion engine of a spark ignition type by grounding an ignition circuit includes a contact section for achieving grounding which is exposed to air flow passing through an engine cooling air passage, to clean off dry grass or other foreign materials from the contact section.

Abstract: An integrated fuel control system for a gasoline engine including a linkage composed of a plurality of pivotable members which enables an operator to effect control of the choking condition of the gasoline engine and the magnitude of its power satisfactorily through a single operating element.

Abstract: A crankchamber precompression type two-cycle internal combustion engine including cylinder assemblies of an even number consists of at least one pair of cylinder assemblies having working cycles with 180.degree. phase difference, each cylinder assembly having a stepped cylinder constituted by a minor diameter cylinder portion and a major diameter cylinder portion, a stepped piston received in the stepped cylinder and constituted by a minor diameter piston portion and a major diameter piston portion, the minor diameter and major diameter piston portions being in sliding engagement with the minor diameter and the major diameter cylinder portions of the stepped cylinder respectively to provide an annular space serving as sub-intake chamber in the major diameter portions of the cylinders, the sub-intake chambers being connected to an auxiliary scavenging nozzle oriented toward a combustion chamber of the other associated cylinder.

Abstract: A by-pass canal of a cooling system in an internal combustion engine for bypassing a cooling liquid between a thermostat and a liquid pump in a shortcircuit. The by-pass canal is formed in a cylinder, and a cylinder head of the engine or formed in a cylinder, a cylinder head and a crank case of the engine without extending outside of the engine.

Abstract: Apparatus for supplying cooling air to an engine of a small vehicle wherein the engine includes a variable speed belt drive having a rotatable drive member that is connected to be rotated by the engine drive shaft. The air supply is driven by the drive member, and includes fan blades attached to the drive member, a casing around the blades, and ducts for conveying the cooling air to the engine. The engine may be either the air-cooled or the liquid-cooled type. The drive member moves axially in response to engine speed variations, and the air supply is arranged to vary the quantity of cooling air in response to variations in the engine speed and the position of the drive member.

Abstract: A by-pass canal of a cooling system in an internal combustion engine for bypassing a cooling liquid between a thermostat and a liquid pump in a shortcircuit. The by-pass canal is formed in a cylinder, and a cylinder head of the engine or formed in a cylinder, a cylinder head and a crank case of the engine without extending outside of the engine.

Abstract: In the present invention, a second expansion chamber which includes a second diffuser is provided in pneumatic connection with the prior art first expansion chamber of an exhaust system for a two-cycle engine. The second expansion chamber creates a second pressure drop or relative vacuum substantially adjacent the point of pneumatic connection between the first and second expansion chambers, which acts to draw-out the exhaust gases present at the rear-cone shaped portion of the first diffuser. The second pressure drop or relative vacuum created by the second expansion chamber of the present invention thus overcomes the deficiencies caused by the pressure increase produced by the rear-cone shaped portion of the first diffuser. Several embodiments of the present invention are disclosed.

Abstract: An internal combustion engine having a gas sealing device including an L-shaped keystone piston ring groove formed on the outer circumferential surface of a piston, and an L-shaped keystone piston ring in pressing contact with the inner surface of a cylinder and fitted in the L-shaped keystone piston ring groove forming a gap for introducing a gas pressure from a combustion chamber into the piston ring groove. The L-shaped keystone piston ring groove includes an outer groove portion underlying a top land formed in the piston, and a wedge-shaped groove portion contiguous with the outer groove portion and tapering in going toward the center axis of the piston. The L-shaped keystone piston ring includes an outer ring portion disposed in the outer groove portion of the piston ring, and a wedge-shaped ring portion disposed in the wedge-shaped groove portion of the piston ring groove.

Abstract: Apparatus for supplying cooling air to the engine of a small vehicle wherein the engine includes a variable speed belt drive having a rotatable drive member that is connected to be rotated by the engine drive shaft. The air supply is driven by the drive member, and includes fan blades attached to the drive member, a casing around the blades, and ducts for conveying the cooling air to the engine. The engine may be either the air-cooled or the liquid-cooled type. The drive member moves axially in response to engine speed variations, and the air supply is arranged to vary the quantity of cooling air in response to variations in the engine speed and the position of the drive member.

Abstract: A cylinder for crankchamber precompression type two stroke engines includes three pairs of main scavenging ports which are symmetrical with respect to a longitudinal plane passing through the centers of the intake and exhaust ports and containing the longitudinal center line of the cylinder. A pair of auxiliary scavenging ports are provided at the opposite sides of the longitudinal plane in such a manner that in a horizontal cross-section the flows from the auxiliary ports do not intersect with the flows from the main ports. Further, the auxiliary scavenging ports are directed further upwardly than the main ports.

Abstract: A cooling system of a liquid-cooled multicylinder engine of the two cycle type, wherein a crank shaft is journalled by bearings housed in bearing housings of a small diameter mounting therein airtight seal members as well as the bearings and located at opposite end portions and an intermediate portion of a crank case consisting of upper and lower members, cylinders are arranged on the upper end surface of the upper crank case member, and each cylinder has a suction conduit attached to one side thereof and an exhaust conduit attached to the other side thereof, includes a centrifugal pump driven by the crank shaft for circulating a cooling liquid and located in a recess on the suction side of the crank case between cylinders, with the axis of the pump being parallel to the crank shaft.

Abstract: A two-cycle engine of the crank chamber preloading type of the construction in which a crankcase, a cylinder head and a cylinder are clamped together by a plurality of clamping members penetrating the cylinder includes a suction port formed in a wall of the cylinder, an exhaust port formed on a side of the cylinder opposite the suction port, at least one main scavenging port disposed between the suction port and the exhaust port and directed toward the suction port, and at least one ancillary scavenging port disposed above the suction port and juxtaposed against the exhaust port. At least one ancillary scavenging passage branching from at least one main scavenging passage and communicating with the ancillary scavenging port extends around an opening for one of clamping members on the suction side.

Abstract: A cylinder head gasket for internal combustion engine, which comprises a gasket body formed with hole for combustion chambers and holes for coolant passages is disclosed, in which protruded portions of high thermal conductivity metal whose thickness is larger than the thickness of the gasket body are provided around the hole for combustion chamber and elastic seal members whose thickness is larger than the thickness of the protruded portions are provided around each of the holes for coolant passages. The gasket body may be made of a metal of high thermal conductivity. In case where the gasket body is made of a material permeable to liquid, the seal members may be provided such that they cover peripheral walls of the holes for coolant passages, respectively.

Abstract: A rope for actuating a recoil starter is trained about a movable pulley outside a main body of the recoil starter, and the movable pulley is rotatably supported by a swing arm or a handle. By moving the swing arm in swinging movement or pulling the handle, the movable pulley can be moved to thereby pull the rope out of the main body of the recoil starter to start the engine. By virtue of the action of the movable pulley, the distance covered by the movement of the swing arm or the handle is smaller than the length of the portion of the rope paid out of the main body of the recoil starter to actuate the recoil starter. At least one further pulley may be provided for guiding the rope in its movement, and a manually operated handle may be additionally attached to the rope. Pulling of the rope automatically makes it possible to actuate an auxiliary engine starting means.

Abstract: Internal combustion engine having one or more cylinders and an engine cover encircling the cylinders with a space for defining a cooling air passage therebetween. The engine cover is made of a non-metallic resilient material such as rubber or resinous material and secured to the engine. The engine cover is formed at its inside surface with one or more projections which are adapted to be fitted to the spaces between cylinder cooling fins.