Working principle of crankshaft

The crankshaft is one of the important components in the engine. Its main function is to withstand the force transmitted by the connecting rod and convert it into torque output through the crankshaft to drive other accessories on the engine. The working principle of the crankshaft can be summarized as follows:

Conversion of force: The crankshaft converts the gas pressure transmitted from the piston connecting rod into torque, which serves as power to output work, drive other working mechanisms, and drive the auxiliary equipment of the internal combustion engine to work.

Structural composition: The crankshaft is generally composed of a front end shaft (free end), a main journal, a connecting rod journal (crank pin), a crank arm, a counterweight, and a rear end flange (power output). These components work together to ensure that the crankshaft can effectively convert and transmit power.

Lubrication system: The lubrication of the crankshaft mainly refers to the lubrication of the connecting rod big end bearing shell and the crankshaft connecting rod neck, as well as the lubrication of the two fixed points. The oil lubricates the working surfaces of the main and connecting rod journals to ensure smooth operation of the crankshaft.

Force analysis: The crankshaft is subjected to the combined action of centrifugal force from rotating mass, periodic gas inertia force, and reciprocating inertia force, which causes the crankshaft to withstand bending and torsional loads. This requires the crankshaft to have sufficient strength and stiffness, as well as good wear resistance and balance.

The working principle of a camshaft is related to the crankshaft, but the camshaft mainly acts on the opening and closing of valves, driving the valve mechanism through its contour, and thereby controlling the engine's intake and exhaust processes. The working principle of marine crankshafts is similar to that of crankshafts in onshore vehicle engines, but may require adaptation and optimization based on specific conditions and requirements of marine engines.