Classification and Application of Gasoline Engine

     The internal combustion engine directly converts the heat energy generated by the combustion of fuel (gasoline, diesel, gas, etc.) in its combustion chamber into mechanical energy.
A powered machine. As a kind of internal combustion engine, gasoline engine is mainly used in motorcycles, cars and trucks with small load, as well as in industrial and agricultural production and national defense construction because of its simple structure, light weight, low cost, balanced work and low noise. . The disadvantage of the gasoline engine is that the fuel price is more expensive and the fuel consumption rate is higher. Gasoline is flammable, so care must be taken when storing it
The gasoline engine products currently developed and planned to be developed by our company include: GN154F, GN168F, GN168F-1, GN170F, GN188F, GN190F, GN192F gasoline engines, etc. And with the gasoline engine as the core power, vigorously develop the water pump unit series, generator set series, and machinery suitable for agriculture, gardens, construction and municipal use.

Internal combustion engines can be divided into four-stroke and two-stroke internal combustion engines according to the number of strokes. A four-stroke internal combustion engine completes a working cycle by four strokes (two rotations of the crankshaft), and a two-stroke internal combustion engine completes a working cycle by two strokes (one rotation of the crankshaft). The working process of a four-stroke gasoline engine consists of intake, compression, combustion, expansion, exhaust Qi consists of five working processes.

1. Intake process. The intake valve starts to open before the top dead center. When the piston moves down from the top dead center, a vacuum is formed in the cylinder, and the combustible mixture is sucked into the cylinder through the intake valve. At this time, when the air flows through the throat of the carburetor, A certain degree of vacuum is formed at the throat, and the gasoline floating in the chamber is ejected from the nozzle under the action of the pressure difference between the atmosphere and the throat, and forms a combustible mixture with air. The carburetor is a special fuel supply device for gasoline engines. According to the working conditions of gasoline engines, air and gasoline are formed into a combustible mixture according to a certain weight ratio. Since the carburetor is equipped with a throttle valve (to control the flow of the combustible mixture), the resistance of the intake valve is larger than that of the diesel engine, and the end pressure Pa of the intake air is lower, about 0.07~0.09Mpa. The temperature of the high-temperature parts of the gasoline engine is higher than that of the diesel engine, and the inlet terminal temperature Ta is also higher than that of the diesel engine, which is about 370~400K. The closing moment of the intake valve is also like a diesel engine, after the bottom dead center.

3. the compression process. After the intake valve is closed, the combustible mixture begins to be compressed. During the compression process, gasoline accelerates vaporization, and all gasoline is vaporized before ignition, forming a relatively uniform combustible mixture with air. Because gasoline is ignited from an external source, the compression ratio S is relatively low, the pressure Po at the end of compression is about 0.8~1.4Mpa, and the temperature at the end of compression is about 600~700K.

3. Combustion process and expansion process. At CA before compression top dead center (10°~15'), the spark plug jumps over and ignites the combustible mixture, forming the center of the flame. Because the mixture of gasoline engine is relatively uniform, the combustion speed of gasoline engine is faster than that of diesel engine, which is close to the constant volume heating cycle , the highest burst pressure is also close to the top dead center. The combustion knot speed point is the same as that of a diesel engine, and it is also on the expansion line, but it ends earlier. The highest explosion pressure Pz of gasoline engine is about 3~5 Mpa, and the highest temperature TZ is about 2200~2700K. The expansion process of a gasoline engine is similar to that of a diesel engine. The difference is that due to the low compression ratio and small expansion ratio, the pressure and temperature at the end of expansion are higher than those of diesel engines (Pb=0.4Mpa, Pb=1200~1500K).

4. the exhaust process. The exhaust process is also the same as that of a diesel engine. However, the valve overlap angle of a gasoline engine is smaller than that of a diesel engine. If the valve overlap angle is too large, due to the inertia of the exhaust gas flow, the combustible mixture that has entered the cylinder will be discharged out of the cylinder together, which will increase the fuel consumption rate. Under certain working conditions, the exhaust gas may even flow back into the intake pipe, causing the combustible mixture in the intake pipe to ignite and burn, resulting in a "blasting" phenomenon, commonly known as backfire. Gasoline engine exhaust terminal pressure Pr=0.105~0.12 Mpa, temperature T=800~1100K.