What is the working principle of a cylinder head?
2 Answers
The working principle of a cylinder head is to seal the cylinder, forming a combustion space together with the piston, and to withstand high-temperature and high-pressure combustion gases. The working conditions of a cylinder head are: 1. The cylinder head is subjected to high-temperature and high-pressure combustion gases, enduring significant bolt preload forces, resulting in substantial mechanical stress. 2. The cylinder head has a complex structure with a highly uneven temperature distribution, leading to significant thermal stress. In severe cases, this can cause cracks and overall deformation in the cylinder head. Therefore, the design requirements for a cylinder head are: (1) Sufficient stiffness and strength to minimize deformation during operation and ensure sealing. (2) Proper arrangement of the combustion chamber, valves, and air passages to ensure the engine's performance. (3) Good manufacturability, with a temperature distribution as uniform as possible to reduce thermal stress and avoid thermal cracking.
As a daily driver, I see the cylinder head as the engine's 'hat,' tightly covering the top of the cylinders to form a sealed chamber. When the engine runs, the pistons move up and down inside the cylinders. The intake valves open to let in the air-fuel mixture, which is compressed before the spark plug ignites it, creating combustion that drives the piston downward. Then, the exhaust valves open to release the burnt gases. Throughout this process, the cylinder head not only secures components like valves and spark plugs but also endures high temperatures and pressure. Inside, it has coolant passages that allow coolant to flow and dissipate heat, preventing engine overheating and damage. For maintenance, regularly checking the cooling system and valve clearances is crucial—otherwise, poor sealing can lead to power loss, coolant leaks, or oil leaks, compromising the vehicle's reliability. In short, the cylinder head ensures the engine runs efficiently, acting as an 'invisible guardian' that springs into action every time I start my car.
