What is an Engine piston and how does it work?
The piston is equivalent to the central component of the car engine and plays an extremely important role when the engine starts. The function of the piston is to convert the gas pressure in the engine combustion chamber into mechanical energy, thereby driving the crankshaft to move.
Working principle: The piston moves up and down in the combustion chamber as the crankshaft rotates. This movement is transmitted to the crankshaft through the connecting rod and converted into rotational power. Through the precise reciprocating motion of the piston, the engine can generate power efficiently.
The movement of the piston is the basis of the engine’s power output and has a direct impact on the overall performance of the engine.
The basic structure of the piston can be divided into the top, the head, and the skirt.
engine piston
Piston top
The top of the piston is the main part of the combustion chamber, and its shape is related to the selected combustion chamber form. For example, gasoline engines use more flat-top pistons because the heat absorption area is small. Diesel engine pistons must adapt to the requirements of diesel engine mixture combustion according to their specific shape, position and size, so there are various pits on the top.
The top of the piston is in direct contact with high-temperature and high-pressure gas, so the material of the top of the piston is usually high-temperature and wear-resistant materials, such as aluminum alloy or steel.
Piston head
The piston head is generally the part above the piston pin seat. The piston head is equipped with piston rings to prevent high-temperature and high-pressure gas from entering the crankcase, and also to prevent engine oil from entering the combustion chamber and affecting the piston movement. In addition, most of the heat absorbed by the top of the piston must also be transferred to the cylinder through the piston head and then conducted out through the cooling medium.
Piston skirt
The part below the piston ring groove is called the piston skirt, which guides the piston to reciprocate in the cylinder and bears the side pressure. At the same time, the shape and size design of the piston skirt helps to keep the piston stable in the cylinder and reduce wear and noise.
Piston type
- The materials used to make pistons are divided into cast iron pistons, steel pistons, aluminum alloy pistons, and combined pistons;
- The fuels used by pistons are divided into gasoline engine pistons, diesel engine pistons, and natural gas pistons;
- The working state of pistons is divided into two categories: non-pressurized pistons and pressurized pistons;
- The process for making piston blanks is divided into gravity casting pistons, extrusion casting pistons, and forged pistons.
There are many ways to distinguish pistons, each of which is based on its specific usage requirements and working conditions. When choosing a piston, you should consider factors such as engine type, power, fuel type, and working environment.