Abstract: A direct cylinder injection-type spark ignition internal combustion engine is disclosed. The engine comprises a spark plug, a cavity formed in the top surface of a piston, and a fuel injection valve for injecting fuel into the cavity in nearly the shape of a fan having a relatively small thickness. When the fuel injected in nearly the shape of a fan from the fuel injection valve is considered by being divided into a plurality of fuel segments in a radial direction, a side wall of the cavity has a first fuel deflection passage 82a and a second fuel deflection passage 82b for so deflecting at least two of the plurality of fuel segments as to pass near the spark plug. The side wall of the cavity is at least partly provided with a return portion 83 that protrudes toward the inside of the cavity.

Abstract: A control device of an engine having cylinders which are divided into two cylinder groups. The first cylinder group is provided with a first throttle valve and a first recirculation valve. The second cylinder group is provided with a second throttle valve and a second recirculation valve. When shifting from full cylinder operation to partial cylinder operation where the second cylinder group is left idle, the sum of the load of both the cylinder groups is maintained as substantially the same load as the total load before shifting to the partial cylinder operation, the first throttle valve is gradually opened, and the second throttle valve is gradually closed.

Abstract: A control device for a variable displacement engine, coupled with an automatic transmission, for an automobile, wherein the control device controls cylinders depending on the driving condition. The control device changes working cylinders without changing the number of working cylinders during the shift operation of the automatic transmission by detecting that the automatic transmission is going to shift. When the control device changes working cylinders without changing the number of working cylinders, the control device controls cylinders so that cylinders which are non-working before the changing work after the changing, and controls cylinders so that a non-working cylinder is not followed by another non-working cylinder in the firing order of the case of all cylinders are working.

Abstract: A two-stroke engine comprising two exhaust valves and two intake valves. These exhaust valves and these intake valves are arranged on the peripheral portion of the inner wall of the cylinder head, and one additional exhaust valve is arranged on the central portion of the inner wall of the cylinder head. The valve openings of the two intake valves, which are located on the exhaust valves side, are masked by the masking walls.

Abstract: A two-stroke engine comprising three exhaust valves and two intake valves. These exhaust valves and these intake valves are arranged on the peripheral portion of the inner wall of the cylinder head, and one additional intake valve is arranged on the central portion of the inner wall of the cylinder head. The valve openings of the three intake valves, which are located on the exhaust valves side, are masked by the masking walls. The central portion of the combustion chamber is scavenged by the fresh air fed from the additional intake valve, and the peripheral portion of the combustion chamber is scavenged by the fresh air fed from the remaining two intake valves.

Abstract: A two-stroke diesel engine comprising a pair of intake valves arranged on one side of the inner wall of the cylinder head, and a pair of exhaust valves arranged on the other side of the inner wall of the cylinder head. The valve openings of the intake valves, which are located on the exhaust valve side, are covered by corresponding masking walls. A prechamber is formed in the cylinder head, and the opening of the prechamber is arranged in the peripheral inner wall portion of the cylinder head, which is positioned farthest from the exhaust valves, between the intake valves.

Abstract: A two stroke engine equipped with a mechanically driven supercharger in the intake passage downstream of throttle valve. A bypass air passage bypassing the supercharger is provided, and a bypass air control valve is arranged in the bypass air passage. When the engine is idling, the bypass air control valve is controlled so that the level of vacuum in the intake passage between the throttle valve and the supercharger is maintained at a constant value.

Abstract: A two-stroke engine having an intake valve and an exhaust valve which are arranged on the cylinder head. A masking wall is formed on the inner wall of the cylinder head to mask the valve opening between the valve seat and the peripheral portion of the intake valve, which is located on the exhaust valve side, for the entire time for which the intake valve is open.

Abstract: In a two stroke fuel injection type internal combustion engine provided with intake and exhaust valves, a basic amount of fuel to be injected is calculated in accordance with an engine load and engine speed. Values of a factor corresponding to a ratio of air captured by an engine cylinder for combustion to the total amount of air introduced into the engine are stored in a memory in accordance with combinations of an engine load and engine speed. A value of a captured air factor corresponding to a detected combination of an engine load and speed is calculated by a map interpolation. The basic amount is corrected by the captured air factor so that a desired air-fuel ratio is obtained. The captured air factor may be further corrected in accordance with a secondary engine condition, other than an engine load and speed, such as a cooling water temperature, intake air temperature, atmospheric air temperature, atmospheric air pressure, exhaust gas temperature, or intake pressure.

Abstract: A two-stroke internal combustion engine comprising a cylinder head 14 having combustion chambers 18 with two intake valves 24 and two exhaust valves 26 arranged therein. Two intake manifolds 30 and 32, respectively, have branch pipes connected to each respective intake port 24. An intake control valve 48 l is arranged in one of the manifold 32, which closes at idling and under a low load of the engine. Further, a swirl S is generated about an axis of the combustion chamber 18 by a portion of exhaust gas caused to flow back from the exhaust ports 22 into the combustion chamber 18 after being once exhausted through the exhaust ports when the exhaust valves are opened, resulting in a two layered stratification in the combustion chamber between fresh air and remaining exhaust gas. A supply of fuel causees a further three layered stratification among a fuel mixture, fresh air, and burned gas, by supplying fuel at alternating cycles of the engine when the engine is under a low load.

Abstract: A two-cycle internal combustion engine having three, or a multiple of three, cylinders comprises a cylinder head having an intake port and exhaust port opened to a combustion chamber, to which fresh air compressed by a supercharger is introduced via an intake valve. The intake and exhaust valves are operated in response to a crank angle. A one-way valve is provided in the intake port so as to prevent air or gas from flowing back toward the supercharger. The 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 the condition. In a heavy load condtion, cross scavenging and air charging effects due to exhaust pulsation can be achieved.

Abstract: A two-cycle internal combustion engine comprises a cylinder head having an intake port and two exhaust ports opened to a combustion chamber, to which compressed fresh air is introduced via an intake valve. The intake valve and two exhaust valves are operated in response to a crank angle. One of the exhaust valves is opened earlier than the other exhaust valve and 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 one 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: 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 lubricating mechanism for a rotary machine, such as a Roots blower, of the class having a pair of vertically spaced parallel shafts (20, 22) which are rotated in synchronization with each other by a pair of meshing gears (36, 38) and are provided with bearings (28, 30) and oil seals (40, 42) requiring lubrication. The rotary machine includes an enclosed gear chamber (70) serving to form an oil sump (74) for lubrication of the meshing gears. The lubricating mechanism is intended to lubricate the oil seal (40) and bearing (28) of the upper shaft (20) of the machine located above and remote from the oil sump. The lubricating mechanism comprises a guiding mechanism (80, 82) for positively guiding the lubricant in the oil sump (74) to be entrained in sequence by the lower gear (38) and the upper gear (36) and lifting the lubricant to the upper region of the gear chamber (70).

Abstract: A by-pass control system for an internal combustion engine provided with a mechanical supercharger arranged in an intake pipe of the engine. The supercharger is connected to a crankshaft by means of a clutch operated in accordance with the engine load as well as the engine speed. A by-pass is arranged so as to by-pass the supercharger, on which by-pass a by-pass control valve is arranged. The by-pass control valve is operated in accordance with the engine speed, so that it is opened during an engine low load and high speed condition. The supercharger is located downstream of the throttle valve, while the by-pass is, on its downstream end, connected to the intake pipe downstream of the throttle valve and upstream of the supercharger.

Abstract: A bypass control system for an internal combustion engine provided with a mechanical supercharger arranged in an intake pipe of the engine. The supercharger is connected to a crankshaft by means of a clutch operated in accordance with the engine load as well as the engine speed. A by-pass is arranged so as to by-pass the supercharger, on which by-pass a by-pass control valve is arranged. The by-pass control valve is operated in accordance with the engine speed, so that it is closed during an engine high load and high speed condition. The by-pass valve is further operated in response to the condition of the clutch so that the by-pass is closed when the clutch is under the disengaged state.

Abstract: A by-pass control system for an internal combustion engine provided with a mechanical supercharger arranged in an intake pipe of the engine. The supercharger is connected to a crankshaft by means of a clutch operated in accordance with the engine load as well as the engine speed. A system is provided for maintaining the clutch disengaged irrespective of the engine load and engine speed when the engine is cranking. The load applied to a starter is decreased during the cranking operating due to the positive disconnection of the supercharger from the crankshaft, so that the engine can be easily started.

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.