Knowledge of engine intake and exhaust valves

Today, the editor brings you automotive knowledge about engine intake valves. The function of the valve is to inject air into the engine and exhaust the exhaust gas after combustion. From the perspective of engine structure, it is divided into intake valves and exhaust valves. The function of the intake valve is to draw air into the engine and mix it with fuel for combustion; The function of the exhaust valve is to exhaust the exhaust gas after combustion and dissipate heat.

The function of the valve is to inject air into the engine and exhaust combustion gases. From the perspective of engine structure, it is divided into intake valve and exhaust valve. The function of the intake valve is to draw air into the engine and mix it with fuel for combustion; The function of the exhaust valve is to exhaust the exhaust gas after combustion and dissipate heat.

In order to improve intake and exhaust efficiency, multi valve technology is now used. It is common for each cylinder to have four valves (there is also a cylinder with a design of three or five valves, and the principle is the same, such as the Audi A6 engine). Four cylinders have 16 valves. We often see "16V" in car data, which means that the engine has 16 valves. This multi valve structure is easy to form a compact combustion chamber, and the arrangement of the fuel injectors in the center can make the fuel gas mixture burn faster and more evenly. The weight and opening degree of each valve are appropriately reduced, making the valve open or close faster.

The intake valve is large because if gasoline is to burn completely, it must require sufficient air and then be compressed, so the intake valve is larger. During the exhaust process, the exhaust valve also pushes the piston out of the exhaust gas to exhaust it from the combustion chamber as soon as possible. So it doesn't need to be that big. We know that the intake port is sucked in through a vacuum, and the exhaust port is squeezed out. The valve is pressed by a cam and closed by a valve spring. When it is necessary to suck the mixture into the cylinder, open the intake valve; When the exhaust gas from combustion needs to be discharged, the exhaust valve will open.

Because the intake air is "sucked in", Exhaust is "pushed" "Exhaust is easy, so intake is more difficult than exhaust. The more intake air, the better combustion, and the better engine performance. Intake depends on vacuum suction, and exhaust will extrude exhaust gas, so exhaust is easier than intake. To obtain more fresh air, parts require more intake air during combustion. Therefore, the intake valve needs to be increased, but the overall size does not change, and the exhaust valve can only be reduced. Therefore, in order to obtain more fresh air in the engine Getting more fresh air to improve the dynamic performance of the vehicle naturally requires more intake air. Therefore, the intake valve must be larger, while the exhaust valve does not have such a requirement. Generally speaking, the design of the intake valve is larger than the design of the exhaust valve to reduce the difficulty of intake and increase the intake volume. More than one intake valve has been designed, so three valves (two intake valves and one exhaust valve) and five valves (three intake valves and two exhaust valves) have been designed.