Fuel injection device
Fuel injection device can be seen as the heart of the engine, the engine is good or bad, whether the fuel is completely burned as fuel, and fuel it can be a good fogging, spraying time, the injection volume has a great relationship, and that a large part depends on the fuel injection device, the pump from the line to the present high pressure common rail technology, we can see, the progress of diesel engines at the same time, the fuel injection system is also changing.
Introduced species
Diesel engine fuel injection systems, from mechanical to electronic control of the present type, its structure and working principle are also different, the nozzle is divided into two kinds of passive and active, the storage form of fuel injection pump through the generations of improvement, there has been quite different.
Diesel fuel injection equipment requirements for
Whether line pump, pump … or high-pressure common rail distribution, the role of the engine are similar, the engine fuel injection device includes basic functions of the fuel pressure, adjust the engine fuel injection quantity and injection each time, will be pressurized fuel into each cylinder a reasonable allocation which make atomization in the combustion chamber.
1 free control injection pressure
Fuel can not burn in the combustion chamber in a very good, and fuel into the combustion chamber of the degree of atomization, the spray to achieve better results, we must require higher injection pressure. The cam driven by mechanical fuel injection systems, cams and other factors determine the shape of the fuel injection pressure, and pressure is at a fixed range – from what produced has been constant. It changes according to their wishes to the engine injection pressure is almost impossible. Only in the electronic control common rail fuel injection system in order to achieve relative freedom control injection pressure.
2 free control injection time
In a traditional pump – pipe – spray system, the use of a certain length of pressure tubing, pressure of the fuel in the fuel pump side of the pressure wave delivered to the nozzle end of the process is a very complex process, it is no way to be effective control, usually by virtue of experience, through the combination of parameters, the final decision by the experimental injection time.
In the traditional mechanical fuel system, is generally used to control fuel injection ahead of time. In the second and third generation electronically engine controlled fuel injection system, using high-speed solenoid valve, the only truly free to control the fuel injection time.
3 free injection rate control
Diesel fuel injection rate shape determines the quality of the combustion process, determines the economic engine, working soft and emission indicators. In the traditional mechanical fuel system, fuel injection rate can not be controlled, in time-controlled electronic fuel systems can more easily control the fuel injection rate. In the common rail system, can easily achieve the pre-injection, multi-stage injection.
4 precise control of fuel injection quantity per cycle
According to the actual engine operating conditions and the prevailing environmental conditions, precise control of the external fuel injection quantity per cycle. In the mechanical fuel system, the mechanical speed control fuel injection, the control accuracy of such systems can not meet the requirements of modern diesel engines. Diesel fuel injection quantity of each cycle depends not only on the external load, and the working environment and the engine and working conditions. Such as environmental temperature and humidity.