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How much do you know about the mysteries of automobile cylinder heads?

The cylinder head is a vital component of an engine. It is installed on the top of the cylinder block and is used to seal the cylinder and form the combustion chamber. It is usually in contact with high temperature and high pressure gas, so it must withstand huge thermal and mechanical loads. For water-cooled four-shaft engines, there is usually a cooling water jacket inside the cylinder head, allowing cooling water to flow through the cooling water holes on the lower end of the cylinder head to cool high-temperature parts such as the combustion chamber. Additionally, the cylinder head contains components such as intake and exhaust valve seats, valve guide holes for mounting the intake and exhaust valves, and intake and exhaust passages.

However, there are some significant differences between the cylinder heads of gasoline and diesel engines. The cylinder head of a gasoline engine is usually machined with spark plug mounting holes, while the cylinder head of a diesel engine is equipped with an injector mounting hole. For shaft engines, the cylinder head will also be machined with camshaft bearing holes for mounting the camshaft. In terms of material, the cylinder head is generally made of gray cast iron or alloy cast iron. Aluminum alloy has excellent thermal conductivity and helps to increase the compression ratio. Therefore, aluminum alloy cylinder heads have become more and more widely used in recent years.

A key function of the cylinder head is to form the combustion chamber, and the shape of the combustion chamber has a significant impact on engine performance. Because gasoline engines and diesel engines have different combustion methods, there are major differences in the parts of their cylinder heads that make up the combustion chamber. In a gasoline engine, the combustion chamber is primarily located in the cylinder head, while in a diesel engine, the combustion chamber is primarily located in a recess on the top of the piston.

Due to the key role of the cylinder head in the engine, there are extremely high requirements for its precision and processing technology. Especially the processing of valve seat rings and guide holes requires very high precision. Generally speaking, the coaxiality tolerance requirement of the valve seat ring and the guide hole of a gasoline engine is (0.015~0.025) mm, while the requirement for a diesel engine is slightly higher, (0.01~0.015) mm. In addition, the taper runout is required to be (0.03~0.05) mm, and the hole accuracy level is usually required to be H7.

Therefore, the manufacturing and processing of the engine cylinder head is very important, and the accuracy requirements of its key parts must be strictly adhered to to ensure the overall performance and quality of the engine. After years of development, Zhengheng Power has become a well-known domestic and foreign production base for engine blocks, cylinder heads, bearing caps, oil pump bodies, gearbox casings, and cast aluminum parts. Provide customers with one-stop service of design, mold, casting and machining. Looking forward to your cooperation!