What is the function of a car piston pin?
2 Answers
The function of the piston pin is to connect the piston and the small end of the connecting rod, transmitting the forces between them. Here is more information about piston pins: 1. The piston pin is subjected to periodic impact loads, undergoes oscillating motion, and operates under poor lubrication conditions. Therefore, the piston pin must have sufficient strength and stiffness, good surface toughness, excellent wear resistance, and be lightweight. Piston pins are generally made into hollow cylinders from low-carbon steel or low-carbon alloy steel. The outer surface undergoes carburizing and quenching treatment to enhance hardness, followed by precision grinding to achieve high dimensional accuracy and surface finish. 2. There are two connection methods for the piston pin with the piston pin bore and the small end bushing of the connecting rod: full-floating and semi-floating connections. In the semi-floating connection, since there is no relative movement between the piston pin and the connecting rod, no retaining ring is needed to limit the axial position of the piston pin. Thus, semi-floating piston pins have no retaining rings, and the small end of the connecting rod has no bushing. Semi-floating piston pins can reduce engine noise and eliminate potential accidents caused by retaining rings, making them commonly used in lightweight high-speed engines.
The piston pin plays a crucial role in a car engine, connecting the piston and connecting rod to allow free rotation. Every time the engine operates, the piston moves up and down in the cylinder, and the explosive force generated is transmitted through the piston pin to the connecting rod, which then converts it into the rotational force of the crankshaft to drive the wheels forward. If the piston pin wears out or gets stuck, the engine will produce knocking sounds, lose power, and in severe cases, may damage the entire engine system. I remember in my own car, due to aged engine oil that wasn't changed in time, lubrication was poor, and the piston pin developed issues—the car made rattling noises during acceleration. A check at the repair shop confirmed it was indeed the problem. So, despite its small size, it's a key component for smooth engine operation, and it's essential to pay attention to the condition of the engine oil during routine maintenance.
