Abstract: A two-cycle internal combustion engine comprises a cylinder head having an intake port and exhaust port opened to a combustion chamber, to which compressed fresh air is introduced via an intake valve. The intake and exhaust valves are operated in response to a crank angle. A pulsation pressure of exhaust gas in the exhaust port is substantially restrained during an idling or light load running condition. The exhaust valve is opened earlier than the intake valve when the speed of the downward movement of the piston is relatively high, such that a part of exhaust gas in the exhaust port flows back to the combustion chamber in that condition. An exhaust gas swirl rotating around a cylinder axis is formed when the exhaust gas flows back and the fresh air is slowly introduced onto the exhaust gas swirl in that condition.

Abstract: A two-cycle internal combustion engine comprises a cylinder head having an intake port and exhaust port opened to a combustion chamber, to which compressed fresh air is introduced via an intake valve. An inclined concavity is formed on a top face of a piston. An exhaust valve is opened earlier than the intake valve when the speed of the downward movement of the piston is relatively high, so that a part of exhaust gas in the exhaust port flows back to the combustion chamber in that condition. An exhaust gas swirl rotating around a cylinder axis is formed when the exhaust gas flows back and the fresh air is slowly introduced onto the exhaust gas swirl in that condition. The inclined concavity serves to smoothly guide the exhaust swirl.

Abstract: A two-cycle internal combustion engine comprises a cylinder head having two intake ports and an exhaust port opened to a combustion chamber, to which compresses fresh air is introduced via two intake valves. The intake and exhaust valves are operated in response to a crank angle. During an idling or light load running condition, an air control valve closes the second intake port. The exhaust valve is opened earlier than the second intake valve, and the first intake valve is opened later than the second intake valve, while the speed of the downward movement of the piston is relatively high. An exhaust gas swirl rotating around a cylinder axis is formed when the exhaust gas flows back into the condition chamber and the fresh air is slowly introduced via the first intake valve onto the exhaust gas swirl in the idling or light load condition. A large amount of fuel is rapidly introduced into the combustion chamber via the second intake valve in a heavy load condition.

Abstract: An alarm signalling electronic timepiece including an alarm signalling circuit which generates alarm signal at a preset hour, and a sound circuit which generates signalling sound by the alarm signal. This timepiece includes a timer counter which can memorize and subtract preset time and which can supply the alarm signal to the sound circuit after the set time elapses from the start of down count from a a time start circuit which holds the time memorized in said timer counter until the alarm signal from the alarm signalling circuit changes and which starts counting in said timer counter when the alarm signal changes, and external switches which externally switch over to work or cancel said time start circuit, whereby plural and different alarm signalling hours can be set with more simplicity.

Abstract: The present invention provides a timpiece including clock and timer sections which can be operated solely or in association with each other. When the clock and timer sections are combined with each other, the start of the timer section is controlled by an alarm signal from the clock section such that two different alarm functions can be attained. The alarm signal is preferably in the form of an alarm output or alarm pause output. The clock and timer secitons may be connected into a unit or mechanically disconnected from each other. When the clock section can be separated from the timer section, the state of connection therebetween and the life of a battery used can warningly be indicated.

Abstract: A double pendulum clock swingingly hanging and supporting two different pendulums including a first pendulum rod swingingly pivoted on a clock body and connected to a first pendulum, a drive magnet attached to the first pendulum rod, a drive coil provided on the clock body to drive the first pendulum by means of electromagnetic coupling with the drive magnet, a second pendulum rod swingingly pivoted on the clock body and connected to a second pendulum, and linking magnets provided at positions facing both of the first pendulum rod and the second pendulum rod and swinging the second pendulum rod in accordance with the swing of the first pendulum rod by means of mutual magnetic force.

Abstract: A whole body swingable clock which includes a clock body swingingly supported on the pendulum fulcrum, an additional pendulum contained in the clock body to swing the clock body by means of movement of gravity center position, said clock body containing a clock drive mechanism having a clock drive gear train to indicate a certain time and an additional pendulum drive mechanism having an additional pendulum drive gear train to drive the additional pendulum, the additional pendulum drive gear train prepared with an escape wheel, a pallet fork which engages with the escape wheel to swing and is connected to the additional pendulum and a urging means which provides the predetermined rotating force to the escape wheel so that the rotation of the escape wheel enables the engaging conditions between the escape wheel and the pallet fork to be changed to swing the pallet fork and the additional pendulum connected thereto and further the whole clock body, wherein the clock drive gear train and the additional pendulum d

Abstract: A supercharger of an internal combustion engine having a Roots-type pump comprising; a pair of rotors rotatably mounted in a pump housing so as to rotate synchronously in opposite directions to suck air from an air inlet and discharge it through an air outlet. The pump housing defines annular spaces around the rotor shafts and between the axial end faces of the rotors and bearings rotatably supporting the rotor shafts. The annular spaces are connected to the atmosphere via a control valve, so that the atmospheric air is introduced into the annular spaces during certain engine driving conditions to reduce the pressure difference existing around the bearings.

Abstract: A cylinder head gasket arranged between a cylinder head and a cylinder block in an internal combustion engine. The cylinder head gasket has a core web of steel with hooks arranged between facing sides of a pair of gasket plates made of a heat resistant resilient material, such as asbestos or graphite. Grommet rings are fitted to edges of openings in the web and the gasket plates aligned corresponding to the respective cylinder bores. The web has regions adjacent to the inner periphery of the aligned openings and located substantially inside of the grommet member rings, the regions containing no hooks, or containing hooks having a reduced height.

Abstract: An apparatus for controlling valve timing in an internal-combustion engine. The apparatus includes a pair of telescoping sleeve members. One of the sleeve members is connected to the camshaft of the engine with a bolt, and the other sleeve member is connected to a timing pulley which is connected to the crankshaft of the engine. Each of the sleeve members has at least one slit which is located adjacent to a slit on the other sleeve member. The adjacent slits are angled relative to each other. Abutment rollers are arranged in the slits and are mounted on an axially movable member. The movable member is connected via a screw mechanism to a rotary motor. The rotational movement of the output shaft of the motor is changed to a linear movement of the support member, thereby causing the support member to move, which movement, in turn, causes the generation of angular displacement between the sleeve members so that variable valve-timing is obtained.

Abstract: In a variable venturi type carburetor having a slow speed system, a fuel vapor conduit is provided, an inlet of which is open to a main fuel passage, an outlet of which is open to an intake passage. Fuel vapor occurring in the main fuel passage is carried through the fuel vapor conduit, so as not to be introduced into a slow fuel passage; thereby, the engine is rotated stably with a relatively lean air-fuel ratio.

Abstract: A fuel controller has a fuel cut-off device in the form of a solenoid valve connected to an intermediate part of an air bleed commmunicating with the well of a variable choke carburetor. The fuel controller also employs a vacuum changeover valve which communicates with the engine intake manifold through a passage way and is connected to the air bleed between the solenoid valve and an air jet upstream of the solenoid valve. The solenoid valve is opened when the engine is decelerating in order to allow the well and the air bleed to communicate with each other, thereby controlling the air-fuel ratio. When the key switch is IC, the air bleed and the vacuum changeover valve communicate with the well, thereby cutting the supply of fuel to the mixing chamber.

Abstract: A multi-gap spark ignition system is disclosed. The system comprises a plurality of spark gaps which are formed in series. The length of the spark gaps increases from the high voltage power source side towards the earth side. According to the present invention, necessary voltage to be applied to the spark ignition system can be decreased.

Abstract: A variable venturi-type carburetor comprising a metering jet and at least one air-bleed bore formed on the cylindrical inner wall of the metering jet. The amount of air fed into the fuel passage of the carburetor from the air-bleed bore is controlled by an output signal from the oxygen concentration detector arranged in the exhaust manifold so that the air-fuel ratio of the mixture fed into the cylinder of the engine becomes equal to the stoichiometric air-fuel ratio. The metering needle is arranged so that it contacts the cylindrical inner wall of the metering jet and partially covers the air-bleed bore.

Abstract: In a variable venturi type carburetor having a slow speed system, a fuel vapor conduit is provided, an inlet of which is open to a main fuel passage, an outlet of which is open to an intake passage. Fuel vapor occurring in the main fuel passage is carried through the fuel vapor conduit, so as not to be introduced into a slow fuel passage; thereby, the engine is rotated stably with a relatively lean air-fuel ratio.

Abstract: An apparatus for controlling valve timing in an internal-combustion engine. The apparatus includes a pair of coaxial sleeves, one inserted into the other. One of the sleeves is connected to a camshaft of the engine, and the other sleeve is connected to a timing pulley which is connected to the crankshaft of the engine. One of the sleeves has diametrically opposite slits while the other sleeve has diametrically opposite slits located adjacent to the respective slits in the one sleeve. The adjacent slits are skewed with respect to each other. Roller-bearing units are arranged in the slits and are mounted on an axially slidable slider. The slider is connected via a screw mechanism to a rotary motor. The rotational movement of the motor is changed to a linear movement of the slider, thereby causing the slider to move, which movement, in turn, causes the generation of angular displacement between the sleeves so as to obtain a variable valve timing.

Abstract: An apparatus for controlling valve timing in an internal combustion engine. The apparatus includes a pair of sleeves inserted into each other. One of the sleeves is connected to a camshaft of the engine. The other sleeve is connected to a timing pulley which is connected to the crankshaft of the engine. One of the sleeves has diametrically opposite slits while the other sleeve has diametrically opposite slits located adjacent to the respective slits in the one sleeve. The adjacent slits have central lines which are skewed with respect to each other. Roller-bearing units are arranged in the slits and are mounted on an axially slidable slider. Movement of the slider causes the generation of angular displacement between the sleeves so as to obtain a variable valve timing.

Abstract: An apparatus for controlling valve timing in an internal-combustion engine. The apparatus includes a pair of sleeves inserted into each other. One of the sleeves is connected to the camshaft and the other sleeve is connected to a timing pulley which is connected to the crankshaft. One of the sleeves has diametrically opposed slits and the other sleeve has diametrically opposed slits located adjacent to the corresponding slits in the first sleeve. Abutment rollers are arranged in the slits and are mounted on an axially slidable slider. Movement of the slider causes the generation of an angular displacement between the sleeves, resulting in variable valve timing. A bearing unit is arranged between the inner and the outer sleeves.

Abstract: A variable venturi-type carburetor comprising a suction piston which has a tip face. A raised wall is formed on the inner wall of the intake passage, which faces the tip face of the suction piston. The raised wall has a substantially straight extending tip edge. The inner wall of the intake passage and the tip edge of the raised wall define a D-shaped air inlet mouth. The connecting portions of the inner wall of the intake passage and the tip edge of the raised wall have an arc shape. The upstream end portion of the tip face of the suction piston and the tip edge of the raised wall define an isosceles triangular air inlet opening therebetween when the amount of air fed into the cylinder of the engine is small.

Abstract: A variable venturi-type carburetor comprising a suction piston which has a tip face defining a venturi portion. The tip face has a flat upstream end portion. A raised wall is formed on the inner wall of an intake passage, which faces the tip face of the suction piston. The raised wall has a tip edge having an approximately V-shaped cross-section. The flat upstream end portion of the tip face of the suction piston cooperates with the tip edge of the raised wall for defining an approximately isosceles triangular-shaped air inlet control opening therebetween when the amount of air fed into the cylinder of an engine is small.