What are the main components of the piston connecting rod assembly?
2 Answers
The piston connecting rod assembly is mainly composed of the piston, piston rings, piston pin, connecting rod, and connecting rod bearing. The piston connecting rod assembly converts the reciprocating motion of the piston into the rotational motion of the crankshaft, while transforming the force acting on the piston into the output torque of the crankshaft. Piston: The main function of the piston is to withstand the gas pressure in the cylinder and transmit this force to the connecting rod through the piston pin to drive the rotation of the crankshaft. It transfers the pressure of the combustion gases to the crankshaft, causing the crankshaft to rotate and output power. The top of the piston also forms the combustion chamber together with the cylinder head and cylinder wall. Piston rings: Piston rings include compression rings and oil rings. During operation, piston rings are subjected to high temperature and high pressure from the gases in the cylinder, resulting in high temperatures. Additionally, their high-speed movement in the cylinder, combined with the deterioration of engine oil at high temperatures and poor lubrication conditions, leads to severe wear. When piston rings wear out and fail, the engine may experience difficulties in starting, insufficient power, increased crankcase pressure, excessive oil consumption, black smoke from the exhaust, and severe carbon buildup on the piston edges. Piston pin: The piston pin connects the piston to the small end of the connecting rod and transmits the gas force acting on the piston to the connecting rod. The piston pin is a hollow cylinder, usually made of low-carbon steel or low-carbon alloy steel with carburizing and quenching, or medium-carbon steel (such as 45# steel) with high-frequency quenching. Connecting rod: The function of the connecting rod is to connect the piston and the crankshaft, converting the reciprocating motion of the piston into the rotational motion of the crankshaft, and transmitting the force received by the piston to the crankshaft. Connecting rod bearing: The connecting rod bearing serves to provide wear resistance, support, and transmission functions.
I find the piston connecting rod assembly quite crucial in an engine, mainly composed of several components: the first is the piston, which moves up and down in the cylinder to compress gases; the second is the piston ring, acting like a seal to prevent gas and oil leaks; the third is the piston pin, connecting the piston to the connecting rod; the fourth is the connecting rod itself, transferring force to the crankshaft; the fifth is the connecting rod bearing, used to reduce friction; and the sixth is the connecting rod bolt, securing the entire assembly. I've seen many old cars with loose connecting rod bolts causing the engine to rattle loudly, and in severe cases, even leading to engine seizure. Therefore, regularly checking the connecting rod clearance and maintaining the engine oil is essential to prolong engine life and ensure smoother operation. It's advisable not to overlook these details—even beginners can monitor abnormalities by checking the oil pressure gauge.
