The number of valves per cylinder refers to the number of valves (including intake and exhaust valves) owned by each cylinder of the engine. There are two types of valves: three-valve, three-valve, four-valve and five-valve. 1 1 Table of Contents 1 Explanation of the number of valves per cylinder 1 The terminology of the number of valves per cylinder explains the number of valves per cylinder refers to the number of valves per cylinder (including intake and exhaust valves), two valves, three valves, There are several types of four valves and five valves. The piston movement of an automobile engine requires air, and the intake valve directly connected to the intake manifold is an inlet for the engine to draw in the mixture, and the exhaust valve is an outlet from which the engine exhausts the combustion exhaust. The number of valves on the engine cylinder head is primarily related to the engine's displacement and speed. When the engine speed is high, the engine valve opening and closing is also very fast, which is easy to cause the engine to take in less air and less power, which is similar to a person running too fast and causing oxygen deficiency. Therefore, the valve lift is increased, but this is easy to cause the valve to be closed in time, so the size of the intake and exhaust valves is increased. The valve is too large, and needs to be reciprocatingly opened and closed, which will increase the weight of the valve seat, resulting in large inertia, high noise and large wear. Then there are multiple air intakes and multiple exhaust ports.