The timing system is an important part of the engine's valve train and one of the important factors to ensure the smooth breathing of the engine. The timing system accurately realizes timing opening and closing of the corresponding intake valve and exhaust valve by controlling the opening and closing time of the valve, so that sufficient fresh air can enter the cylinder in time, and exhaust gas can be discharged from the cylinder in time, thus ensuring that the engine has normal, Good power output performance.

　　 timing system actuator

At present, the main working process of most engine timing systems is: the camshaft is driven by the crankshaft through a chain or belt to operate, and the valve lifter is pressed by the rotation of the cam working surface, and then the valve is pushed into the cylinder to realize the valve is opened. ; After the cam working surface rotates, the valve will return under the action of the valve spring, and the valve will be closed.

　　 Which kind of timing chain and belt is better?

　　 The transmission parts of the timing system are divided into two types: timing chain and timing belt. Many people are concerned about which transmission type is better. Timing belts have been used in engines for a long time. The technology is mature, the cost is low, and the noise is low, but it needs regular inspection and maintenance. Generally, 50,000 to 100,000 kilometers need to be replaced. The timing chain has significant advantages such as compact structure, high transmission power, high reliability and wear resistance, and lifetime maintenance-free. However, compared with the traditional timing belt, its noise is generally slightly higher. But nothing is absolute. With the advancement of technology, tooth-shaped mute chains are currently used in some cars, and the noise is even lower than that of timing belts. It is believed that the widespread use of this timing chain will bring more convenience to the majority of car users.

　　 Tooth-shaped silent chain

　　 At present, common timing chains are mainly divided into two types: sleeve roller chains and toothed chains. Among them, the roller chain is affected by its innate structure, the rotation noise will be more obvious than the timing belt, and the transmission resistance and inertia will be correspondingly larger. What we usually call the "silent chain" adopts a tooth-shaped structure design, which makes the teeth softer during transmission, has less impact, and runs more smoothly. In addition, there is no chain roller structure that produces noise, so it can perform at the noise level. The upper is better than the traditional timing belt.