Abstract: An engine includes: a crankshaft 12; a camshaft 36; and a timing transmission system 37 which has a drive rotation member 45, a driven rotation member 46, and an endless power transmission member 47, and which provides connection between the crankshaft 12 and the camshaft 36. An access window 55 through which the driven rotation member 46 is attached to and detached from the camshaft 36 is opened in an outer end surface 5c of the cylinder head 5. A lid body 57 for closing the access window 55 is jointed to the outer end surface 5c. The outer end surface 5c of the cylinder head 5 comprises a slanted surface 5c which is inclined so that at least a part of an outer periphery of the driven rotation member 46 on a side opposite from the drive rotation member 45 is exposed from the access window 55.

Abstract: A multipurpose engine has a wiring structure between the generator and electrical components. A connector box is provided in a gap defined directly between the generator and the fuel tank. A plurality of electrical wirings is interconnected inside the connector box.

Abstract: The engine equipped with a generator is provided. The stator fixed to the crankcase includes a plurality of iron cores arranged in the circumferential direction about the crankshaft, and coils that are wrapped around the plurality of iron cores. The rotor includes a flywheel that is fastened to the crankshaft by a fixing mechanism, and a plurality of permanent magnets fixed to the flywheel. The fixing mechanism mounts the flywheel on the crankshaft in a position in which the center of one permanent magnet among the plurality of permanent magnets coincides with the center point between two mutually adjacent iron cores among the plurality of iron cores when the piston is at the top-dead-center or the bottom-dead-center.

Abstract: There is provided an air-cooled engine (10) that is cooled by cooling air. The air-cooled engine (10) comprises a cylinder block (33), and a cylinder head (28) that closes off one end of a cylinder (26). The cylinder head (28) includes a base part (81) that is superposed on and secured to the cylinder block (33) by a plurality of bolts (91), and a valve compartment (83) formed integrally on the base part (81). All of the bolts (91) are disposed near the outer periphery of the base part (81) at positions outside of the valve compartment (83).

Abstract: A muffler unit for a general-purpose engine includes a muffler (40) having a maze of sound-deadening chambers (101, 102, 103) defined therein and an inlet pipe (85) disposed inside the muffler. The inlet pipe has an open end (106) connected to an exhaust port of the engine via an exhaust pipe (43), a closed end (107) opposite to the open end, and perforations (108) provided near the open end and connecting an internal space of the inlet pipe and a first sound-deadening chamber (101). The closed end of the inlet pipe is exposed to the outside air, so that exhaust gasses are cooled when the gasses impinge on the closed end of the inlet pipe.

Abstract: An air-cooled engine (10) has a fan cover (16) for covering a cooling fan (14). The cover (16) is composed of a fan-cover peripheral wall (44) for covering the outside of the cooling fan (14), and a top board (45) for closing off one end of the fan-cover peripheral wall (44). The fan-cover peripheral wall (44) has an internally disposed guiding duct (47) for guiding cooling air (Wi) from the cooling fan (14) to an engine main body (12). A first fastening member (42) secures a portion of the external part of the fan-cover peripheral wall (44) that is proximal to the guiding duct (47) to a casing (25) of the engine main body (12). A second fastening member (41) extends from the casing (25) and through the fan-cover peripheral wall (44), and secures a top board (45) in a portion that is at a distance from the guiding duct (47).

Abstract: An engine includes: a crankshaft 12; a camshaft 36; and a timing transmission system 37 which has a drive rotation member 45, a driven rotation member 46, and an endless power transmission member 47, and which provides connection between the crankshaft 12 and the camshaft 36. An access window 55 through which the driven rotation member 46 is attached to and detached from the camshaft 36 is opened in an outer end surface 5c of the cylinder head 5. A lid body 57 for closing the access window 55 is jointed to the outer end surface 5c. The outer end surface 5c of the cylinder head 5 comprises a slanted surface 5c which is inclined so that at least a part of an outer periphery of the driven rotation member 46 on a side opposite from the drive rotation member 45 is exposed from the access window 55.

Abstract: A multipurpose engine having an improved wiring structure between the generator (46) and electrical components is disclosed. A connector box (104) is provided to the dead space formed between the engine main body (27) and the fuel tank (37). A plurality of electrical wirings (151 to 156) is interconnected inside the connector box.

Abstract: There is provided an air-cooled engine (10) that is cooled by cooling air. The air-cooled engine (10) comprises a cylinder block (33), and a cylinder head (28) that closes off one end of a cylinder (26). The cylinder head (28) includes a base part (81) that is superposed on and secured to the cylinder block (33) by a plurality of bolts (91), and a valve compartment (83) formed integrally on the base part (81). All of the bolts (91) are disposed near the outer periphery of the base part (81) at positions outside of the valve compartment (83).

Abstract: An engine (10) equipped with a generator (20) is provided. The stator (24) fixed to the crankcase (12) includes a plurality of iron cores (32a to 32l) arranged in the circumferential direction about the crankshaft (16), and coils (33) that are wrapped around the plurality of iron cores (32a to 32l). The rotor (42) includes a flywheel (25) that is fastened to the crankshaft (16) by a fixing mechanism (28), and a plurality of permanent magnets (26a to 26f) fixed to the flywheel. The fixing mechanism (28) mounts the flywheel (25) on the crankshaft (16) in a position in which the center of one permanent magnet (26a) among the plurality of permanent magnets (26) coincides with the center point between two mutually adjacent iron cores (32a and 32b) among the plurality of iron cores (32a to 32l) when the piston is at the top-dead-center or the bottom-dead-center.

Abstract: An air-cooled engine (10) has a fan cover (16) for covering a cooling fan (14). The cover (16) is composed of a fan-cover peripheral wall (44) for covering the outside of the cooling fan (14), and a top board (45) for closing off one end of the fan-cover peripheral wall (44). The fan-cover peripheral wall (44) has an internally disposed guiding duct (47) for guiding cooling air (Wi) from the cooling fan (14) to an engine main body (12). A first fastening member (42) secures a portion of the external part of the fan-cover peripheral wall (44) that is proximal to the guiding duct (47) to a casing (25) of the engine main body (12). A second fastening member (41) extends from the casing (25) and through the fan-cover peripheral wall (44), and secures a top board (45) in a portion that is at a distance from the guiding duct (47).

Abstract: A muffler unit for a general-purpose engine includes a muffler (40) having a maze of sound-deadening chambers (101, 102, 103) defined therein and an inlet pipe (85) disposed inside the muffler. The inlet pipe has an open end (106) connected to an exhaust port of the engine via an exhaust pipe (43), a closed end (107) opposite to the open end, and perforations (108) provided near the open end and connecting an internal space of the inlet pipe and a first sound-deadening chamber (101). The closed end of the inlet pipe is exposed to the outside air, so that exhaust gasses are cooled when the gasses impinge on the closed end of the inlet pipe.

Abstract: A four-cycle OHC engine includes timing transmitting device that includes a driven wheel formed integrally with a valve-operating cam and that is disposed between a valve operation system and a crankshaft. The valve operation system includes the valve-operating cam, which is rotatably supported on a support shaft that is supported in an engine main body. Lubricating oil is supplied to a valve operation chamber. Provided between the upper part of the engine main body and one end of the support shaft is an oil intake passage in which the upper end opens upward on the base of the valve operation chamber and the lower end is closed. Provided on the outside of the lower part of the support shaft is a flat surface for forming an oil passage between the flat surface and the valve-operating cam and driven wheel. One end of the oil passage communicates with the oil intake passage, and the other end of the oil passage opens downward and communicates with a housing passage.

Abstract: A four-cycle OHC engine includes timing transmitting device that includes a driven wheel formed integrally with a valve-operating cam and that is disposed between a valve operation system and a crankshaft. The valve operation system includes the valve-operating cam, which is rotatably supported on a support shaft that is supported in an engine main body. Lubricating oil is supplied to a valve operation chamber. Provided between the upper part of the engine main body and one end of the support shaft is an oil intake passage in which the upper end opens upward on the base of the valve operation chamber and the lower end is closed. Provided on the outside of the lower part of the support shaft is a flat surface for forming an oil passage between the flat surface and the valve-operating cam and driven wheel. One end of the oil passage communicates with the oil intake passage, and the other end of the oil passage opens downward and communicates with a housing passage.

Abstract: An oil reservoir chamber, a crank chamber and a valve-operating chamber are provided in an engine body. The oil reservoir chamber and the crank chamber are in communication with each other through a through-hole, and the crank chamber and the valve-operating chamber are in communication with the each other through a one-way valve which is opened upon rising of the pressure in the crank chamber. The valve-operating chamber and the oil reservoir chamber are in communication with each other through an orifice. By utilizing a pressure pulsation in the crank chamber, an oil mist produced in the oil reservoir chamber is circulated from the oil reservoir chamber to the crank chamber, the valve-operating chamber and the oil reservoir chamber. Thus, in any operational attitude of an engine, the lubricating oil can be circulated without use of special oil pump.

Abstract: An oil reservoir chamber, a crank chamber and a valve-operating chamber are provided in an engine body. The oil reservoir chamber and the crank chamber are in communication with each other through a through-hole, and the crank chamber and the valve-operating chamber are in communication with the each other through a one-way valve which is opened upon rising of the pressure in the crank chamber. The valve-operating chamber and the oil reservoir chamber are in communication with each other through an orifice. By utilizing a pressure pulsation in the crank chamber, an oil mist produced in the oil reservoir chamber is circulated from the oil reservoir chamber to the crank chamber, the valve-operating chamber and the oil reservoir chamber. Thus, in any operational attitude of an engine, the lubricating oil can be circulated without use of special oil pump.

Abstract: A 4-cycle engine, includes an engine body, having a piston, a crankshaft and a crank chamber, an independent oil reservoir chamber adjacent the crank chamber, the crankshaft extending into the oil reservoir chamber from the crank chamber, an oil mist generator disposed in the independent oil reservoir chamber and being secured to and driven by the crankshaft, and a valve-operating chamber. Further, the engine includes a first passageway connecting the oil reservoir chamber with the crank chamber to provide oil mist communication therebetween, a second passageway connecting the crank chamber with the valve-operating chamber to provide oil mist communication therebetween, and a third passageway connecting the valve-operating chamber with the independent oil reservoir chamber to provide oil communication therebetween, wherein the three chambers and the three passageways form a lubrication oil feed channel to provide one-way circulation of lubrication oil therethrough.

Abstract: A 4-cycle engine, includes an engine body having a piston, a crankshaft and a crank chamber, an oil reservoir chamber adjacent the crank chamber and independent therefrom, the oil reservoir chamber having an oil mist generator therein drivably connected to the crankshaft, and a valve-operating chamber. Further, a first passageway connects the oil reservoir chamber with the crank chamber to provide oil mist communication therebetween. A second passageway connects the crank chamber with the valve-operating chamber to provide oil mist communication therebetween. Additionally, a third passageway connects the valve-operating chamber with the independent oil reservoir chamber to provide oil communication therebetween, wherein the three chambers and the three passageways form a lubrication oil feed channel to provide one-way circulation of lubrication oil therethrough.

Abstract: A system for lubricating a 4-cycle engine includes a crank chamber having a crank portion of a crankshaft contained therein and storing a lubricating oil therein, a valve operating chamber having a valve-operating device contained therein, wherein the crank chamber and the valve-operating chamber are provided in an engine body. An oil mist producing means is provided in the crank chamber for producing an oil mist from the lubricating oil. The crank chamber and the valve operating chamber are in communication with each other above an oil level of the lubricating oil in the crank chamber through a control valve which is opened upon rising of the pressure in said crank chamber and closed upon reduction of the pressure in said crank chamber. The valve-operating chamber is substantially in communication at its upper portion with the atmosphere, and in communication at its bottom with the crank chamber through an orifice.

Abstract: An oil reservoir chamber, a crank chamber and a valve-operating chamber are provided in an engine body. The oil reservoir chamber and the crank chamber are in communication with each other through a through-hole, and the crank chamber and the valve-operating chamber are in communication with the each other through a one-way valve which is opened upon rising of the pressure in the crank chamber. The valve-operating chamber and the oil reservoir chamber are in communication with each other through an orifice. By utilizing a pressure pulsation in the crank chamber, an oil mist produced in the oil reservoir chamber is circulated from the oil reservoir chamber to the crank chamber, the valve-operating chamber and the oil reservoir chamber. Thus, in any operational attitude of an engine, the lubricating oil can be circulated without use of special oil pump.