The engine crankshaft is the main rotating mechanism of the engine. It is responsible for transforming the up and down reciprocating motion of the piston into its own circular motion, and usually what we call the engine speed is the speed of the crankshaft.
The crankshaft will wear out the contact surface between the big end of the connecting rod and the journal due to the unclean oil and uneven force on the journal. If there are hard impurities with large particles in the oil, there is also the risk of scratching the journal surface. If the wear is severe, it is likely to affect the stroke length of the piston up and down, reduce the combustion efficiency, and naturally reduce the power output. In addition, the crankshaft may also cause burns on the journal surface due to insufficient lubrication or too thin oil, which may affect the reciprocating motion of the piston in severe cases. Therefore, lubricating oil of suitable viscosity must be used, and the cleanliness of the oil must be ensured.
