The characteristics of traditional diesel engines: thermal efficiency and economy is better, diesel engine adopts compressed air to improve air temperature, so that the air temperature exceeds the ignition ignition point of diesel fuel, then spray into diesel, diesel spray and air mixing at the same time their own ignition combustion. Therefore, the diesel engine does not need the ignition system. At the same time, diesel engine oil supply system is relatively simple, so the reliability of diesel engines is better than gasoline engines. Due to the limitation of deflagration and the need of diesel spontaneous combustion, diesel engine compression is high. Thermal efficiency and economy are better than gasoline engines, at the same time in the case of the same power, the diesel engine torque is large, the maximum power of low speed, suitable for the use of trucks.
But diesel engines are under pressure, the relevant parts are required to have high structural strength and stiffness, so the diesel engines are bulky and larger; the diesel fuel injection pump and nozzle manufacturing precision requirements are high, so the cost is higher; In addition, diesel engine work rough, vibration noise, diesel oil is not easy to evaporate, cold in winter car start difficult.
Because of the above characteristics, formerly diesel engines are generally used in large and medium trucks. The new development of small and high speed diesel engines: Emission has reached the European standard of No. III. Traditionally, diesel engines have been less favored by cars because of the heavier, higher-power indices than gasoline engines (lower rotational speeds), noise and vibrations, and carbon smoke and particulate (PM) emissions are more serious. But with the progress of diesel engine technology in recent years, especially the new development of small high speed diesel engines, a number of advanced technology, such as direct injection, common rail, turbo, medium-cooling technology can be used in small diesel engines, so that the original diesel engine shortcomings have been better solved, and the advantages of the diesel engine in energy-saving and CO2 emission, the engine, including gasoline engines, all the thermodynamic motors can not be replaced, so, advanced small high-speed diesel engines, Its emissions have reached the Euro III standard, become a "green engine", now has become Europe and the United States many new car power plant, can be foreseen, China will appear more and more diesel cars.