Views: 87 Author: Site Editor Publish Time: 2021-05-04 Origin: Site
Anyone who learns a little about the engine knows that there is a big difference between a petrol engine and a diesel engine. Of course, the most significant difference is that the petrol engine burns petrol while the 4stroke 6cylinder diesel engine burns diesel. For the combustion mode, the two are also obviously different. Diesel engine has large power and high thermal efficiency, so petrol engine has learned a lot of technology from diesel engine. The performance of petrol engine is constantly improved after the debugging and optimization of engineers, so as to achieve the purpose of energy saving and emission reduction.
The fuel of diesel engine is diesel, its viscosity is higher than petrol and it is not easy to evaporate. When the 4stroke electric starting diesel engine is working, the air entering the cylinder is compressed to the end point and the gas is in the state of high temperature and high pressure. Petrol has low viscosity and fast evaporation. The engine's injection system injects petrol into the intake port and mixes with air to form combustible mixture.
GDI technology is stolen from high speed 6cylinder diesel engine by petrol engine. The injection system of direct injection engine injects petrol directly into combustion chamber to form fuel air mixture. It should be emphasized that the direct injection petrol engine still compresses the mixture, which only changes the injection position from the intake port to the combustion chamber. However, diesel engines compress air, which is a significant difference between petrol engines and diesel engines.
Turbocharging technology was first used in marine powerful 12cylinder diesel engines and then gradually used in military aircraft and warships. In the early development history of automotive turbocharging power, caterpillar is one of the first enterprises to extend turbocharging technology to passenger car engines. Turbocharging is the use of engine exhaust gas caused by the inertial impulse to promote the turbine in the turbine chamber. Then, the impeller driven by the turbine compresses and delivers the air from the air filter pipe and pressurizes it into the cylinder.
The ratio of total cylinder volume to combustion chamber volume is an important structural parameter of internal combustion engine. The compression ratio of petrol engine is 9-11 and that of high speed 6cylinder diesel engine generator is 15-22. In general, increasing the compression ratio can improve the efficiency of the engine. This is also the key reason why the efficiency of diesel engine is higher than that of petrol engine. Therefore, automotive engineers are still trying to improve the compression ratio of petrol engine by various means without strong knock, so as to improve the thermal efficiency of petrol engine.
"Petrol is ignited, diesel is compression ignition." this is a common sense about the engine, but this common sense is gradually being broken. Homogeneous charge compression ignition (HCCI) is a new combustion mode based on the previous dual petrol engine. In short, it is a compression ignition mode of petrol engine, which has the advantages of homogeneous mixture of traditional petrol engine and high combustion efficiency of 4stroke turbocharger diesel engine.
At present, the development trend of petrol engine is "diesel engine assimilation ". Turbocharging and direct injection, which were once used in new motor 6cylinder diesel engine generators, are gradually popularized in petrol engines, which improve the performance and thermal efficiency. Some of these technologies are under research and are expected to appear in petrol engines, such as compression ignition (HCCI).