0816201 PISTON For HITACHI ZX270-3 4HK1

The main functions of the piston include composing the combustion chamber, bearing the gas force, sealing the cylinder to prevent gas leakage and lubricating oil from entering the combustion chamber, transferring heat to the cylinder wall, and transferring the lateral pressure of the connecting rod to the cylinder wall. According to the cylinder form, the piston can be divided into single-acting type, double-acting type and differential type. In addition, pistons can be divided into two types according to whether they bear lateral force or not: one is a piston that is directly connected with a connecting rod through a piston pin and bears lateral force, such as a cylindrical piston; The other kind is the piston that does not bear the lateral force, which is connected with the connecting rod through the piston rod and crosshead, and the lateral force is borne by the crosshead, such as disc piston and differential piston. To sum up, as a key component of the engine, the design, material selection and type of the piston directly affect the performance and efficiency of the engine.

The piston is a reciprocating component in the cylinder block of an automobile engine. Its main function is to bear the combustion pressure in the cylinder and transmit this force to the crankshaft through the piston pin and connecting rod. The design and material selection of piston have an important influence on its performance. The basic structure of piston includes top, head and skirt. The top is the main part of the combustion chamber, and its shape varies according to the selected combustion chamber form. Gasoline engines often use flat-topped pistons to reduce the heat absorption area. However, the piston top of diesel engine often has various pits to meet the requirements of mixture formation and combustion.

The working principle of the piston is to convert the pressure generated by fuel combustion into mechanical energy by moving up and down in the cylinder to drive the engine to run. Specifically, the piston moves up and down in the cylinder, and the pressure generated when the fuel burns pushes the piston to move down, which is converted into rotary motion through the connecting rod and crankshaft, thus driving the automobile forward. At the same time, the piston ring plays a sealing role in the cylinder, ensuring the tightness of the combustion chamber and preventing gas leakage. The piston consists of piston top, piston head and piston skirt, in which the piston top, cylinder head and cylinder wall together form the combustion chamber, which is the key part of the engine combustion process. Piston rings include gas rings and oil rings, which are responsible for sealing and scraping oil respectively to ensure the normal operation and lubrication of the engine. The piston pin connects the piston with the small end of the connecting rod and transmits the gas pressure borne by the piston to the connecting rod to further drive the crankshaft to rotate.