摘要:
For the purpose of preventing a decompression passageway in a two-cycle engine from being blocked by carbon soot, facilitating manufacture of a two-cycle engine having decompression structure and eliminating reduction of output power of the two-cycle engine caused by the decompression structure, a known two-cycle engine includes a scavenging passageway formed along an inner wall of a cylinder. The scavenging passageway is directed in the axial direction of the cylinder and communicates with a crank case of the engine. A decompression groove extends in the axial direction of the cylinder on the upstream side of a cylinder cooling airflow at a top end portion of the scavenging passageway. The width and depth of the decompression groove are either varied along the axial direction of the groove so as to be narrowed towards a tip end thereof directed toward a plug, or are provided with a narrowed portion of venturi shape.
摘要:
In order to supply a sufficient quantity of lubricating oil to the entire valve operating mechanism, we designed a lubrication device for an overhead valve engine. A first breather passage goes from the valve operating mechanism chamber to the crankcase, passing through the cylinder head and cylinder. The first breather passage opens in the vicinity of the spring retainer for the intake valve on the surface of the cylinder head which faces the valve operating mechanism chamber for the valve operating mechanism. The opening of the first passage and the vicinity of the exhaust valve are connected by a second breather passage. This second passage comprises a groove formed by cutting in the valve operating mechanism chamber surface of the cylinder head, and a tunnel formed between an oil guide wall which goes up from the valve operating mechanism chamber surface of the cylinder head and the peripheral wall of the head. One end of this groove connects to the opening of the first breather passage.
摘要:
To simplify the assembling process to mount a valve operating mechanism on a cylinder head, one intake valve and one exhaust valve are mounted on the cylinder head symmetrically with respect to the axis of a cylinder shaft. A rocker arm supporting base which supports rocker arms is fixed to the top of the cylinder head. Rocker arm shafts are supported by the base. The central portions of the rocker arms engage with the rocker arm shafts in such a way that the arms are free to swing. Push rods and the intake and exhaust valves are engaged with the ends of the arms. The valve operating mechanism is enclosed in a head cover which is fixed to the top surface of the cylinder head. This engine is distinguished by having the mounting surface for the rocker arm supporting base, on which the rocker shafts are mounted, and the surface on which the head cover sits be virtually coplanar. This makes it possible to machine the two surfaces at the same time. In order to supply a sufficient quantity of lubricating oil to the entire valve operating mechanism, a particularly designed lubrication device is provided.
摘要:
A direct-injection spark-ignition engine including a governor for sensing the rotational speed of the engine, fuel injection pumps for injecting fuel at a rate which may be increased or decreased by a fuel control rack connected to the power shaft of the governor, fuel injection nozzles for directly injecting the fuel from the pumps into the respective engine cylinders, ignition plugs for igniting and burning the fuel charges injected from the nozzles by spark discharge, and suction air passages through which air flows toward the combustion chambers, characterized by throttle valves each of which is mounted within each suction air passage to open or close the same, and throttle control mechanisms each of which is connected to the throttle valve and the fuel control rack to open or close the valve in such a way that the valve opening is increased in proportion to an increase in the quantity of fuel injection.