The function of the camshaft is to control the opening and closing of the valve. The working principle of the camshaft is: the constant rotation of the automobile camshaft drives the valve stem to move up and down, thus controlling the opening and closing of the valve. By changing the curve of camshaft, the valve opening and closing time can be precisely adjusted.
The symptoms of damaged camshaft of vehicle engine are as follows:
1. The vehicle has high pressure fire, but the starting time is long, and the vehicle can finally run;
2. During the starting process, the engine crankshaft will overturn and the intake branch pipe will be quenched;
3. The vehicle vibrates seriously at idle speed, similar to the common fault of vehicle cylinder shortage;
4. The car doesn't speed up enough, the car can't run, the speed ratio exceeds 2500 rpm;
5. The car consumes high gasoline and diesel, and the industrial exhaust gas exceeds the standard. The exhaust pipe will form black smoke.
The daily tasks undertaken by gas turbine valves are very heavy, but the working conditions of the valves are very poor; This makes it difficult for the valve to perform this daily task very well.
At present, the scientific research on valves is developing rapidly, and many delicate design schemes have been selected, such as mushroom valve, rotary valve, rolling valve and lifting valve. Although the lift valve has some defects, it is still widely used.
The lifting valve is noisy and difficult to cool, but its structure is simple and the sealing effect is good under working conditions. The valve operates under extreme conditions.
The valve is in direct contact with the ignited vapor in the combustion chamber, and unlike the combustion chamber, it is surrounded by cooling water; They are not cooled by oil like piston rods.
The ignition temperature in the combustion chamber of the automobile engine can reach 2700 ℃ instantly. Then, the exhaust valve must be opened to make the hot air flow quickly from the top of the valve head to the middle of the cylinder head.