In some two-stroke motorcycle engines, in order to avoi […]
In some two-stroke motorcycle engines, in order to avoid the back spray phenomenon of the carburetor at low speed, a one-way reed valve for controlling the intake air is installed between the carburetor and the cylinder block. The reed is made of thin spring steel sheet, the valve seat is made of aluminum alloy, and the air inlet is opened. The air inlet surface and the reed contact part are pasted with a layer of oil rubber to reduce the impact and vibration of the reed and the valve seat. . When inhaling, a certain degree of vacuum is formed in the crankcase. Under the action of the pressure difference, the reed valve opens the mixed gas into the crankcase. When the piston descends, the air inlet is not opened, and the pressure in the crankcase rises. The valve is closed to prevent the backflow of the mixture, which improves the power and economy of the engine at low speed.
The four-stroke engine uses a combination of splash lubrication and pressure lubrication. Two-stroke engines generally use a hybrid lubrication method in which gasoline is mixed with a certain proportion of QB gasoline engine oil. However, this kind of slip-type mixed oil is supplied to the slip oil in a predetermined proportion regardless of the operating conditions of the engine, which increases the consumption of the lubricating oil, incomplete combustion, more carbon deposit, and exhaust pollution. The new generation of two-stroke engines are split and slippery, with separate oil and oil pumps.
The oil pump generally adopts a reciprocating plunger type variable oil supply oil pump, which is driven by a crank gear through a worm wheel and a worm. The oil supply is linked by the throttle handle, the control cable and the carburetor throttle valve, so that the oil supply varies with the engine speed. At high speed, the oil supply is high, the oil supply is low at low speed, the oil supply is reasonable, and the mixing is smooth. Compared with the way, it can save more oil. The oil is blown into a small oil mist by the high-speed mixed gas, and is supplied to the part that needs to be smoothed, and the oil that enters the combustion chamber is reduced, the mixed gas is completely burned, and the carbon deposit and the exhaust pollution are reduced.