Food testing items GB 7069-2014 National Food Safety Standard Edible Fungi and Their Products

A diesel engine is an engine that burns diesel to obtain energy release. It was invented by German inventor Rudolf Diesel in 1892. In honor of this inventor, diesel is represented by his surname Diesel, and diesel engines are also known as Diesel engines. The advantages of diesel engines are high torque and good economic performance. The working process of diesel engines shares many similarities with gasoline engines, and each working cycle also undergoes four strokes: intake, compression, power, and exhaust. However, due to the fact that the fuel used in diesel engines is diesel, which has a higher viscosity than gasoline and is less prone to evaporation, and its self ignition temperature is lower than gasoline, the formation and ignition method of the combustible mixture are different from gasoline engines. The main difference is that the mixture in the cylinder of a diesel engine is compression ignition rather than ignition. When a diesel engine is working, air enters the cylinder. When the air in the cylinder is compressed to the end point, the temperature can reach 500-700 ℃ and the pressure can reach 40-50 atmospheres. When the piston approaches the top dead center, the fuel injection nozzle of the fuel supply system injects fuel into the combustion chamber of the cylinder at extremely high pressure in a very short time. The diesel forms fine oil particles, which are mixed with high-pressure and high-temperature air. The combustible mixture burns on its own and expands violently to generate explosive force, pushing the piston downward to do work. At this time, the temperature can reach 1900-2000 ℃, the pressure can reach 60-100 atmospheres, and the torque generated is very large, So diesel engines are widely used in large diesel equipment. The characteristics of traditional diesel engines: good thermal efficiency and economy. The diesel engine uses compressed air to raise the air temperature, so that the air temperature exceeds the diesel fuel's self ignition point. At this time, diesel fuel, diesel fuel spray and air are injected and ignited at the same time. Therefore, diesel engines do not require an ignition system. At the same time, the fuel supply system of diesel engines is relatively simple, so the reliability of diesel engines is better than that of gasoline engines. Due to the freedom from detonation and the need for diesel self ignition, the compression ratio of diesel engines is very high. The thermal efficiency and economy are better than gasoline engines. At the same power, diesel engines have high torque and low rotational speed at maximum power, making them suitable for use in trucks. However, due to the high working pressure, diesel engines require all relevant parts to have high structural strength and stiffness, making them relatively bulky and bulky; The manufacturing accuracy requirements for the fuel injection pump and nozzle of diesel engines are high, so the cost is relatively high; In addition, the diesel engine operates rough and has high vibration and noise; Diesel fuel is not easy to evaporate and it is difficult to start when the car is cold in winter. Due to the above characteristics, diesel engines were generally used on large and medium-sized heavy-duty trucks in the past. Traditionally, diesel engines have been rarely favored by sedans due to their bulkiness, lower power output compared to gasoline engines (with lower speeds), higher noise and vibration, and severe emissions of carbon smoke and particulate matter (PM). Especially with the new development of small and high-speed diesel engines, a number of advanced technologies, such as electronically controlled direct injection, common rail, turbocharging, intercooling, etc., have been applied to small diesel engines, effectively addressing the shortcomings of the original diesel engine. The advantages of diesel engines in energy conservation and CO2 emissions are irreplaceable by all thermal engines, including gasoline engines, becoming "green engines"