An engine is a machine that converts the chemical energy of the combustible mixture into mechanical energy, in which the piston plays a vital role. There are two types of piston movement modes: reciprocating piston type and rotary piston type. Nowadays, most of the cars on the market use the reciprocating engine movement mode, which is to push the crankshaft to rotate through the up and down movement of the piston to achieve the purpose of doing work.

1. Reciprocating piston type: The working cycle of the four-stroke is four strokes of intake, compression, power and exhaust.

Under the intake stroke, the intake valve opens and the exhaust valve closes. The piston moves from the top dead center to the bottom dead center. The cylinder inhales air and injects gasoline and air to form a flammable mixture. When the piston passes the bottom dead center, the intake valve closes. , the piston begins to move upward to compress the combustible mixture.

Under the compression stroke, the piston moves to the top dead center, the intake and exhaust valves are closed, the pressure in the cylinder rises, and the temperature can reach 300℃-400℃.

During the power stroke, the piston runs to the top dead center, the spark plug emits an electric spark to ignite the combustible mixture, the pressure continues to rise, and the temperature rises to 2200℃-2500℃. , the exhaust valve is closed.

When the power stroke ends, the exhaust valve opens and the piston moves to the top dead center. At this time, the pressure in the cylinder is greater than the pressure outside the cylinder, and the exhaust gas is quickly discharged.

2. Rotary piston type: Compared with the reciprocating piston engine, the rotary piston engine uses the rotor to replace the reciprocating motion of the reciprocating piston. When the rotary engine is working, the combustion gas pressure on the arc surface pushes the rotor to rotate, which in turn drives the main shaft to rotate. output power.

A rotary piston engine refers to an internal combustion engine in which the high temperature and high pressure gas generated in the combustion chamber drives the piston to rotate to generate power.

The reciprocating engine combines the inhaled air with the atomized fuel in the cylinder to form a combustible mixture, which is compressed and then burned. Circular motion, thereby outputting power.