Working principle of two-stroke gasoline engine

1. Composition of gasoline engine

Gasoline saws generally use crankcase pre-pressure scavenging two-stroke machines, which are cylinder air cooled. According to the function, the gasoline engine is composed of four systems: mechanical, electrical, oil supply and air flow.

1) Mechanical system including cylinder, piston group, connecting rod, crankshaft, box, etc. The function is to achieve gas sealing, withstand gas pressure and mechanical force, and ensure a certain movement relationship.

2) The electrical system includes magneto, ignition coil, spark plug, etc. Its function is to generate electric energy by the magneto driven by the crankshaft and complete the timely high-pressure ignition of the cylinder.

3) The oil supply system consists of a fuel tank, a fuel tank switch, an oil filter, an oil pipeline and a carburetor. Its role is to store and provide fuel oil, lubricating oil, and mix fuel oil and air into an appropriate proportion of combustible gas.

4) The air flow system includes air filter, intake valve, exhaust muffler, etc., which is used to provide combustion-supporting air, bring oil into the cylinder and reduce exhaust noise.

Second, the basic working principle

When the power drive crankshaft, the piston group is implicated by the crankshaft and connecting rod. When the piston moves towards the top of the cylinder (up), the crankcase produces negative pressure, and the air passes through the air filter and the fuel is carried by the carburetor. When the piston moves away from the cylinder (down), the gas in the crankcase is compressed. When the scavenging port is open, the gas is pressed into the cylinder through the scavenging port. When the piston moves upward again, the gas is compressed in the cylinder, the pressure and temperature are increased, and the heat gas pressure is further increased. Gas expansion, driving the piston downward movement to drive the crankshaft rotation, output power, when the exhaust port is open, the exhaust gas after combustion is first ejected by pressure, and then swept out of the cylinder by scavenging gas flow drive, discharged by the muffler, intake, compression, expansion, exhaust, cycle, the crankshaft will continue to rotate, do work.

When the crankshaft is idle, the clutch is separated, and the crankshaft rotation does not drive the drive shaft, which meets the need to stop the drive shaft without stopping. When the crankshaft speed rises above the clutch combined speed, the clutch is combined, the drive shaft rotates, and the machine is driven to work, and the machine starts or stops, fast or slow is controlled by the throttle control.

Three, the characteristics and classification of gasoline engines

The term "gasoline engine" can generally refer to all kinds of power engines, different energy sources to produce power, power engines can be divided into electric motors, wind engines, hydraulic engines and so on. As a mobile power engine, the thermal engine that converts heat energy into mechanical energy is the most common, the "heat" of the heat engine is generated by fuel combustion, combustion in the engine, this engine is called the internal combustion engine, the internal combustion engine also has a piston and rotating impeller structure, the common internal combustion engine is a reciprocating piston type, with the use of different fuels, Internal combustion engines can be divided into gasoline engines, diesel engines, kerosene engines, etc., gasoline engines are internal combustion engines that burn gasoline.