Abstract: An engine comprising a piston having a cavity formed on the top face thereof. A projection having an impingement face at the top thereof is formed at the center of the cavity. Fuel is injected from a fuel injector toward the impingement face to form a richer air-fuel mixture around the projection. A spark plug or a glow plug is arranged to ignite the richer air-fuel mixture at the end of the compression stroke.

Abstract: An engine comprising one pair of scavenge ports alternately covered and uncovered by a piston, a richer air-fuel mixture and a leaner air-fuel mixture being separately fed into the cylinder from the scavenge ports, the richer air-fuel mixture flowing into the cylinder towards the inner wall thereof, located opposite the exhaust port, and the leaner air-fuel mixture flowing into the cylinder so that it overlays the richer air-fuel mixture.

Abstract: A 2-stroke engine having a combustion chamber and a scavenge port which is open to the combustion chamber. When the engine is operating under a light load in which a large amount of unburned components, incompletely burned components and oxygen remains in the combustion chamber, fresh air is fed into the combustion chamber from the scavenge port at a low speed so that the fresh air does not disturb the residual gas in the combustion chamber. As a result of this, oxidation of the unburned components and the incompletely burned components continues without interruption during the expansion stroke and the compression stroke and causes self-ignition of the residual gas at the end of the compression stroke. The self-ignited residual gas causes ignition of the fuel injected into the combustion chamber from a fuel injector.

Abstract: A 2-cycle engine having a transfer passage communicating the crank room with the combustion chamber. An accumulation tank having a volume which is larger than the stroke volume of the piston is arranged in the transfer passage. A reed valve is arranged in the transfer passage between the crank room and the accumulation tank.

Abstract: Disclosed is an engine drive type generator blower comprising a generator directly connected to the output shaft of the engine, and a blower directly connected to the rotary shaft of the generator. The engine is enclosed by a stationary duct having on its forward end a cold air inlet. A catalytic converter for purifying the exhaust gas is arranged in the stationary duct. The air inlet opening of the blower is enclosed by a rotary duct which can be connected to the stationary duct. When the rotary duct is connected to the stationary duct, hot air is discharged from the blower. When the rotary duct is directly opened into the atmosphere, cold air is discharged from the blower.

Abstract: A 2-cycle engine having a transfer passage communicating the crank case with the combustion chamber. The transfer passage comprises a first passage and a second passage. The first passage has a long length and a small cross-sectional area for causing a fresh combustible mixture to flow at a high speed. The second passage has a short length and a large cross-sectional area for causing a fresh combustible mixture to flow at a low speed. An exhaust gas recirculation device is provided for recirculating the exhaust gas from the exhaust system into the intake system of the engine.

Abstract: A 2-cycle engine having a scavenging passage communicating the crank case with the combustion chamber. The scavenging passage comprises a first passage and a second passage. The first passage has a long length and a small cross-sectional area for causing a fresh combustible mixture to flow at a high speed. The second passage has a short length and a large cross-sectional area for causing a fresh combustible mixture to flow at a low speed. In order to easily start the engine, a fuel pump is provided for directly feeding the fuel into the crank case in response to the operation of the choke mechanism when the engine is started.

Abstract: A 2-cycle engine having a transfer passage communicating the crank case with the combustion chamber. The transfer passage comprises a first passage and a second passage. The first passage has a long length and a small cross-sectional area for causing a fresh combustible mixture to flow at a high speed. The second passage has a short length and a large cross-sectional area for causing a fresh combustible mixture to flow at a low speed. The second passage is connected to the crank room via the bypass passage. A normally closed valve is arranged in the bypass passage. The valve is opened when the engine is operating under a heavy load.

Abstract: Disclosed is a 2-cycle engine having a scavenging passage communicating the crank case with the combustion chamber. The scavenging passage comprises a first passage and a second passage. The first passage has a long length and a small cross-sectional area for causing a fresh combustible mixture to flow at a high speed. The second passage has a short length and a large cross-sectional area for causing a fresh combustible mixture to flow at a low speed. The vaporization of the fresh combustible mixture is prometed in the first passage and, in addition, the fresh combustible mixture flows into the combustion chamber at a low speed. As a result of this, an active thermoatmosphere combustion is caused in the combustion chamber.