Diesel engines, gas engines, genset and engine parts.sightseeing train,sightseeing train model:YQHC-20,YQHC-30I,YQHC-60I,YQHC-80I


                                 Four-stroke engine
    In order to ensure adequate engine cylinder intake and exhaust valves thoroughly requires the greatest possible capacity, the engine's intake and exhaust valve opening and closing is not just the actual on piston bottom dead center, but right ahead and after the late.
Early intake valve open The aim is to ensure fresh gas or combustible gas mixture into the cylinder can be smoothly enough. The purpose of the intake valves close late, in order to take advantage of the beginning of the compression stroke pressure inside the cylinder temporarily below atmospheric or ambient pressure, intake air flow by inertia so that fresh gas or combustible gas mixture is likely to continue into the cylinder, so that the intake the valve opening time duration of the crank angle is greater than 180 degrees in fact
Exhaust valve open as early as the purpose is to close when the piston pressure stroke bottom dead center, combustion and expansion of the combustible mixture has been completed, but the gas pressure inside the cylinder is still high, with this pressure can quickly exhaust cylinder discharge.
The purpose of the exhaust valve off late, because the piston reaches top dead center, the pressure inside the cylinder is still higher than the atmospheric pressure, the use of exhaust gas allows Liu inertia continues to drain, so that the exhaust valve opening crank angle Length of time it is greater than 180 degrees.
Since the early intake valve and the exhaust valve opening night off, there will be a period of time intake and exhaust valves open at the same time the phenomenon of the intake and exhaust valves open at the same time that period of time or crank angle, we put it called valve overlap time or the valve overlap angle, valve overlap angle is equal to the size of the intake valve and exhaust valve open angle early evening and the closing angle.
Since the valve overlap angle is small and the inertia of the fresh gas and exhaust gas flow to maintain the original direction of flow, so long as the valve overlap angle made appropriate, it does not produce exhaust gas back into the intake manifold and exhaust emissions with fresh gas and other issues.

                                   Two-stroke engines
    Two-stroke engines do not have valves, which simplifies their structure, reducing the own weight.
    Two-stroke engines fire once every rotation, while the four-stroke engine ignition once every one turn, two-stroke engine which gives important impetus basis.
    Two-stroke engine can operate in any orientation, which is very important in some equipment such as chain saws, the standard four-stroke engine failure may occur when the fuel sloshing, unless it is upright, to solve this problem would be greatly increased engine flexibility.
    Two-stroke engines are not like a four-stroke engine so long as the sustainable use of precision means less lubrication system of two-stroke engine parts wear faster.
    Two-stroke engines need to add in the fuel oil, while gasoline also burning fuel oil, oil consumed in large quantities.
    Two-stroke engine fuel consumed in large quantities.
    Two-stroke engine emissions exceeded, first, because the lubricating oil combustion engine smoke, and second, whenever a large number of new air into the combustion chamber fuel injection, some of the gas mixture is discharged from the exhaust port, incomplete combustion in the exhaust pipe.