Describe the valve knowledge of Cummins diesel generator set in detail
2021-12-07
With the continuous progress of engine technology, various valve mechanisms emerge in endlessly, so the requirements for valve clearance are also different. For example, some engine valve mechanisms need valve clearance, while others do not. Some engines give cold clearance, some give hot clearance, and others give cold and hot clearance at the same time. Various regulations often bring great inconvenience to practical work. This paper will explain the relationship between valve mechanism and valve clearance according to different valve mechanisms.
1. Side mounted valve
Camshaft height of side mounted valve mechanism. The valve tappet is driven by the cam, and then the valve is pushed by the tappet. The transmission chain of the mechanism is short, the structure is simple and the dynamic response is good. In the past, FAW CA10B gasoline engine used this system. However, because the inlet angle of this kind of engine is too large and the flame propagation distance is long, which is not conducive to improving the engine performance, except for the engines of small lawn mowers and snow sweepers, the structure is basically no longer used in high-power and high-speed gasoline engines.
2. Overhead valve with high camshaft
The driving mode of overhead valve mechanism with high camshaft is that the cam drives the tappet, push rod and rocker arm, and then the rocker arm pushes the valve. CA141 and EQ6100 of FAW and FAW adopt this mechanism. The transmission chain of the mechanism is long and is not suitable for high-speed engines.
3. Camshaft overhead valve
Camshaft overhead valve mechanism is a kind of camshaft directly driven by crankshaft through toothed belt or chain, so the valve mechanism has good rigidity and is suitable for high-speed engine. It is also the most commonly used type of light vehicle and car engine. Its working modes are generally as follows: (1) cam direct drive type; (2) Cam pressure rocker arm, rocker arm pressure gate type; (3) Cam top rocker arm, rocker arm compressor gate type.
4. Engine valve - Chongqing Cummins diesel generator set
The valve mechanism of engine is an important part of the whole valve system. Its function is to ensure that the engine can absorb as much gas mixture or air as possible in the intake stage during the working process of the engine, and seal reliably in the compression and power stage of the engine. Because the valve mechanism bears the high temperature from the combustion of the engine and the cooling from the intake air, its working environment is very bad. The valve mechanism varies greatly in structure with different engine types.
For a four stroke engine, the type of valve mechanism is also different because of different engine speeds. In addition, due to the effect of temperature during combustion, the valve stem causes thermal expansion due to direct heating by fuel gas. Therefore, in order to ensure reliable sealing of the valve in any case, even when the engine is overheated, a certain clearance must be reserved at the valve head.
1. Side mounted valve
Camshaft height of side mounted valve mechanism. The valve tappet is driven by the cam, and then the valve is pushed by the tappet. The transmission chain of the mechanism is short, the structure is simple and the dynamic response is good. In the past, FAW CA10B gasoline engine used this system. However, because the inlet angle of this kind of engine is too large and the flame propagation distance is long, which is not conducive to improving the engine performance, except for the engines of small lawn mowers and snow sweepers, the structure is basically no longer used in high-power and high-speed gasoline engines.
2. Overhead valve with high camshaft
The driving mode of overhead valve mechanism with high camshaft is that the cam drives the tappet, push rod and rocker arm, and then the rocker arm pushes the valve. CA141 and EQ6100 of FAW and FAW adopt this mechanism. The transmission chain of the mechanism is long and is not suitable for high-speed engines.
3. Camshaft overhead valve
Camshaft overhead valve mechanism is a kind of camshaft directly driven by crankshaft through toothed belt or chain, so the valve mechanism has good rigidity and is suitable for high-speed engine. It is also the most commonly used type of light vehicle and car engine. Its working modes are generally as follows: (1) cam direct drive type; (2) Cam pressure rocker arm, rocker arm pressure gate type; (3) Cam top rocker arm, rocker arm compressor gate type.
4. Engine valve - Chongqing Cummins diesel generator set
The valve mechanism of engine is an important part of the whole valve system. Its function is to ensure that the engine can absorb as much gas mixture or air as possible in the intake stage during the working process of the engine, and seal reliably in the compression and power stage of the engine. Because the valve mechanism bears the high temperature from the combustion of the engine and the cooling from the intake air, its working environment is very bad. The valve mechanism varies greatly in structure with different engine types.
For a four stroke engine, the type of valve mechanism is also different because of different engine speeds. In addition, due to the effect of temperature during combustion, the valve stem causes thermal expansion due to direct heating by fuel gas. Therefore, in order to ensure reliable sealing of the valve in any case, even when the engine is overheated, a certain clearance must be reserved at the valve head.