Abstract: A choke valve structure includes an air cleaner body having a suction pipe portion provided on an end wall, a choke valve having a valve body allowed to adhere to a sealing surface formed around an opening, and a movement mechanism configured to move the choke valve along a direction parallel to the sealing surface such that the valve body moves in closing and opening directions. A blowing back prevention plate disposed on an axial line of the suction pipe portion to face the opening is provided integrally with the air cleaner body. A protrusion, allowed to come into contact with the blowing back prevention plate when the valve body moves in the closing direction, is provided on the valve body. The valve body is pressed against the sealing surface to adhere thereto when the protrusion conies into contact with the blowing back prevention plate.

Abstract: A peripheral wall portion of a piston is provided with a through hole penetrating through the peripheral wall portion. A cylinder is provided with a scavenging passage having a first opening being open in a bore surface and configured to make a bore section and a crank chamber communicate with each other and is provided with a communication passage having a second opening being open in the bore surface on the other side with respect to the first opening and configured to make the bore section and the scavenging passage communicate with each other. The cylinder and piston are configured so that the through hole overlaps the second opening to communicate with the communication passage in a partial interval of a scavenging stroke in which the first opening becomes open in the bore surface on one side of the piston with reciprocal motion of the piston.

Abstract: A choke valve structure includes an air cleaner body having a suction pipe portion provided on an end wall, a choke valve having a valve body allowed to adhere to a sealing surface formed around an opening, and a movement mechanism configured to move the choke valve along a direction parallel to the sealing surface such that the valve body moves in closing and opening directions. A blowing back prevention plate disposed on an axial line of the suction pipe portion to face the opening is provided integrally with the air cleaner body. A protrusion, allowed to come into contact with the blowing back prevention plate when the valve body moves in the closing direction, is provided on the valve body. The valve body is pressed against the sealing surface to adhere thereto when the protrusion conies into contact with the blowing back prevention plate.

Abstract: A peripheral wall portion of a piston is provided with a through hole penetrating through the peripheral wall portion. A cylinder is provided with a scavenging passage having a first opening being open in a bore surface and configured to make a bore section and a crank chamber communicate with each other and is provided with a communication passage having a second opening being open in the bore surface on the other side with respect to the first opening and configured to make the bore section and the scavenging passage communicate with each other. The cylinder and piston are configured so that the through hole overlaps the second opening to communicate with the communication passage in a partial interval of a scavenging stroke in which the first opening becomes open in the bore surface on one side of the piston with reciprocal motion of the piston.

Abstract: A pair of suction-side scavenging ports introduces a working gas containing fuel into a combustion chamber, and the working gases are caused to collide with each other to thereby form a working gas layer in a state of two vortexes rotating in opposite directions to each other, and a pair of exhaust-side scavenging ports introduces a non-working gas having a lower fuel content rate than the working gas into the combustion chamber, and the non-working gases are caused to collide with each other to thereby form a non-working gas layer in a state of one vortex.

Abstract: A two-stroke engine has a scavenging port for introduction of a working gas containing fuel, into a combustion chamber, and an exhaust port for discharge of gas in the combustion chamber therefrom, in which a piston connected to a crankshaft through a connecting rod reciprocates in the combustion chamber with rotary drive of the crankshaft, to control opening and closing of the scavenging port and the exhaust port, in which as the piston moves from a top dead center to a bottom dead center, the exhaust port and the scavenging port open in the order named, and in which as the piston moves from the bottom dead center to the top dead center, the scavenging port and the exhaust port close in the order named.

Abstract: An object is to provide a two-stroke engine achieving effective reduction of blow-by while implementing efficient gas exchange.

Abstract: A two-stroke engine includes a scavenging passage opening in a combustion chamber in a scavenging stroke to fill the combustion chamber with a working gas containing a fuel; and a scavenge filling chamber communicating through a communicating port with the scavenging passage and arranged to be filled with a non-working gas in a fuel weight concentration smaller than that of the working gas prior to the scavenging stroke. In the scavenging stroke, the scavenging passage and the scavenging filling chamber are made open in the combustion chamber and the non-working gas in the scavenge filling chamber is forced into the combustion chamber by the working gas inside the scavenging passage through the communicating port to scavenge the combustion chamber.

Abstract: A two-stroke engine of the present invention has a scavenging passage 19 opening in a combustion chamber 12 in a scavenging stroke to fill the combustion chamber with a working gas containing a fuel; and a scavenge filling chamber 18 communicating through a communicating port with the scavenging passage 19 and arranged to be filled with a non-working gas in a fuel weight concentration smaller than that of the working gas prior to the scavenging stroke. In the scavenging stroke, the scavenging passage 19 and the scavenge filling chamber 18 are made open in the combustion chamber 12 and the non-working gas in the scavenge filling chamber 18 is forced into the combustion chamber 12 by the working gas inside the scavenging passage 19 through the communicating port to scavenge the combustion chamber 12.

Abstract: A backpack type irrigation apparatus having a backpack frame, a pump attached to the frame, an internal combustion engine serving as a driving source for the pump, and a discharge hose connected to a discharge port of the pump. A throttle lever of the internal combustion engine may be attached to the backpack frame. With this arrangement, the pump and the engine can be moved together with the discharge hose, and also a suction hose can be moved. Accordingly, the water-supply range is enlarged. Also, the discharge amount can be adjusted by operating the throttle lever while driving the pump.

Abstract: Provided are starters for securely starting an internal combustion engine. The starters have a reel rotatably mounted in a case, a starting rope wound on the reel, a rotor rotatably mounted in the case, a spring for storing energy with rotation of the rotor in a predetermined direction, an engaging mechanism for engaging the reel with the rotor with pullout of the starting rope to transmit a torque of the reel to the rotor to store energy in the spring, and an engagement release mechanism for releasing the engagement between the reel and the rotor at the start of rewinding of the starting rope onto the reel to rotate the rotor by a restoring force of the spring. This arrangement permits the internal combustion engine to be started readily and securely.

Abstract: Apparatuses and methods for controlling HC in exhaust, with Schnuerle type 2-cycle engine. When piston reaches near dead center point, the ends of the channel at the bottom end of piston reach from outlet ports and No. 1 transfer ports, and exhaust gas from outlet ports moves to the top of No. 1 transfer ports, and there a specified amount is kept. With scavenging, the pair of No. 1 transfer ports open first to combustion chamber, and the exhaust gas is introduced to combustion chamber, after which the pair of No. 2 transfer ports is opened to combustion chamber, and the air-fuel mixture is introduced to combustion chamber. Exhaust gas first introduced from No. 1 transfer ports creates a reverse eddy, and there is scavenging within combustion chamber, purging gas as it is into exhaust port. Air-fuel mixture introduced later from No. 2 transfer ports is limited in purging, and is kept in combustion chamber.

Abstract: Apparatuses and methods for reducing hydrocarbons in two-stroke engine exhaust. When a piston is close to top dead center, a groove in the lower end region of the piston confronts an exhaust port and first scavenging ports, respectively, and exhaust gas from the exhaust port is directed to the first scavenging ports. During a scavenging stroke, the first scavenging ports open first to a combustion chamber and exhaust gas is introduced to the combustion chamber, and a second pair of scavenging ports then opens to the combustion chamber and introduces a fuel-containing gas to the combustion chamber. When crankcase pressure reaches 142 Pa or higher, a relief valve opens and maintains the maximum pressure at 142 kPa or lower. Thus, blending in the combustion chamber of the exhaust gas from the first scavenging ports and the fuel-containing gas from the second scavenging ports is suppressed, and short-circuiting of the fuel component to the exhaust port is suppressed.

Abstract: Provided are starters for securely starting an internal combustion engine. The starters have a reel rotatably mounted in a case, a starting rope wound on the reel, a rotor rotatably mounted in the case, a spring for storing energy with rotation of the rotor in a predetermined direction, an engaging mechanism for engaging the reel with the rotor with pullout of the starting rope to transmit a torque of the reel to the rotor to store energy in the spring, and an engagement release mechanism for releasing the engagement between the reel and the rotor at the start of rewinding of the starting rope onto the reel to rotate the rotor by a restoring force of the spring. This arrangement permits the internal combustion engine to be started readily and securely.

Abstract: A backpack type irrigation apparatus having a backpack frame, a pump attached to the frame, an internal combustion engine serving as a driving source for the pump, and a discharge hose connected to a discharge port of the pump. A throttle lever of the internal combustion engine may be attached to the backpack frame. With this arrangement, the pump and the engine can be moved together with the discharge hose, and also a suction hose can be moved. Accordingly, the water-supply range is enlarged. Also, the discharge amount can be adjusted by operating the throttle lever while driving the pump.

Abstract: A two-stroke cycle engine having an improvement of its power output while reducing total hydrocarbons in the exhaust gases. The two-stroke cycle engine comprises a crank chamber adapted to receive a fuel mixture through feed means and a combustion chamber in a cylinder. Scavenging ports are provided for communication between the combustion chamber and the crank chamber to transfer the fuel mixture from the crank chamber to the combustion chamber while a exhaust port is provided for exhausting the burned gases from the combustion chamber. Reciprocation of the piston results in increase or decrease in volume of the combustion chamber while opening or closing the exhaust port and the scavenging ports. Communication means are provided for communicating the exhaust port with the crank chamber via the scavenging ports to draw a portion of the burned gases from the exhaust port into the crank chamber when the piston is in its top dead center.

Abstract: Apparatuses and methods for reducing hydrocarbons in two-stroke engine exhaust. When a piston is close to top dead center, a groove in the lower end region of the piston confronts an exhaust port and first scavenging ports, respectively, and exhaust gas from the exhaust port is directed to the first scavenging ports. During a scavenging stroke, the first scavenging ports open first to a combustion chamber and exhaust gas is introduced to the combustion chamber, and a second pair of scavenging ports then opens to the combustion chamber and introduces a fuel-containing gas to the combustion chamber. When crankcase pressure reaches 142 Pa or higher, a relief valve opens and maintains the maximum pressure at 142 kPa or lower. Thus, blending in the combustion chamber of the exhaust gas from the first scavenging ports and the fuel-containing gas from the second scavenging ports is suppressed, and short-circuiting of the fuel component to the exhaust port is suppressed.

Abstract: Apparatuses and methods for controlling HC in exhaust, with Schnuerle type 2-cycle engine. When piston reaches near dead center point, the ends of the channel at the bottom end of piston reach from outlet ports and No. 1 transfer ports, and exhaust gas from outlet ports moves to the top of No. 1 transfer ports, and there a specified amount is kept. With scavenging, the pair of No. 1 transfer ports open first to combustion chamber, and the exhaust gas is introduced to combustion chamber, after which the pair of No. 2 transfer ports is opened to combustion chamber, and the air-fuel mixture is introduced to combustion chamber. Exhaust gas first introduced from No. 1 transfer ports creates a reverse eddy, and there is scavenging within combustion chamber, purging gas as it is into exhaust port. Air-fuel mixture introduced later from No. 2 transfer ports is limited in purging, and is kept in combustion chamber.

Abstract: A two-stroke cycle engine having an improvement of its power output while reducing total hydrocarbons in the exhaust gases. The two-stroke cycle engine comprises a crank chamber adapted to receive a fuel mixture through feed means and a combustion chamber in a cylinder. Scavenging ports are provided for communication between the combustion chamber and the crank chamber to transfer the fuel mixture from the crank chamber to the combustion chamber while a exhaust port is provided for exhausting the burned gases from the combustion chamber. Reciprocation of the piston results in increase or decrease in volume of the combustion chamber while opening or closing the exhaust port and the scavenging ports. Communication means are provided for communicating the exhaust port with the crank chamber via the scavenging ports to draw a portion of the burned gases from the exhaust port into the crank chamber when the piston is in its top dead center.