The engine assembly is the heart of the vehicle, consisting of two major mechanisms and five major systems, as follows:

First, the two major mechanisms include the crankshaft and connecting rod mechanism and the valve train. The crankshaft and connecting rod mechanism converts heat into mechanical energy and is primarily composed of components such as the cylinder block, crankcase, cylinder head, piston, piston pin, connecting rod, crankshaft, flywheel, flywheel connecting box, and shock absorber. The valve train, consisting of components such as the intake and exhaust valve assemblies, camshaft, air filter, and intake manifold, is responsible for the intake and exhaust processes and ensures sufficient fuel combustion.

Second, the five major systems include the fuel supply system, lubrication system, cooling system, ignition system, and starting system. The fuel supply system is responsible for delivering fuel and ensuring complete combustion in the combustion chamber. The lubrication system, consisting of the oil pump, oil filter, pressure regulator, safety devices, and lubrication oil passages, maintains lubrication of engine components and reduces wear. The cooling system, comprising components such as the water pump, oil radiator, thermostat, fan, and radiator tank, ensures a moderate engine temperature. The ignition system ignites the fuel mixture at the appropriate time for complete combustion of the fuel. The starting system starts the engine and ensures normal operation.

Finally, the engine block assembly consists of the engine block, cylinder liners, cylinder head, and oil pan. The engine block is the foundation of the engine. The cylinder liners support the pistons, the cylinder head seals the combustion chamber, and the oil pan stores lubricating oil.

In summary, the engine assembly, through the coordinated work of two major mechanisms and five major systems, converts chemical energy into mechanical energy, providing power to the vehicle and ensuring its normal operation.