Gasoline engines usually consist of two mechanisms and five systems, while diesel engines lack an ignition system. The structural diagram of a gasoline engine is shown in the figure below.

Crank connecting rod mechanism

The crank connecting rod mechanism is the core mechanism for the engine to realize thermal function conversion. It mainly consists of the engine block (cylinder block, cylinder head, oil pan), piston-connecting rod group (piston, piston ring, piston pin, connecting rod body, connecting rod cover, connecting rod bolt) and crankshaft flywheel group (crankshaft and flywheel).

Valve mechanism

In order to maintain a continuous engine working cycle, the intake valve and exhaust valve must be opened and closed regularly to charge the mixture into the cylinder and discharge the exhaust gas. For this purpose, the engine is equipped with a valve train. It is mainly composed of the valve group (valve, valve guide, valve spring) and valve drive group (timing gear, camshaft, lifter, pushrod, rocker arm, rocker arm shaft).

Fuel supply system

The traditional carburetor fuel supply system generally consists of a gasoline tank, a gasoline pump, a gasoline filter, a carburetor, an air filter, and an intake manifold. Pipe, exhaust manifold, exhaust muffler, etc. Its function is to mix gasoline and air into a combustible mixture of appropriate proportions and send it into the cylinder, and the exhaust gas produced after combustion is discharged into the atmosphere.

Ignition system

The high-voltage spark generated by the gasoline engine ignition system promptly ignites the combustible mixture in the cylinder. It is mainly composed of a battery, a generator, a distributor, an ignition coil, a spark plug, and an ignition switch.

Cooling system

Water cooling system generally consists of water pump, thermostat, radiator, fan, circulating water jacket, water distribution pipe, etc. Its function is to dissipate excess heat from parts to maintain the normal operating temperature of the engine.

Lubrication system

The function of the lubrication system is to deliver lubricating oil to the friction surfaces of relatively moving parts, reduce the wear and tear of the parts, and play the roles of cooling, cleaning the surface of the parts, sealing, and reducing friction. Vibration and anti-rust function. It generally consists of an oil pump, filter, pressure limiting valve, lubricating oil passage, coarse oil filter, fine oil filter, oil cooler, etc.

Starting system

Including starter and its accessories, used to start the engine.