Common Rail Diesel Engine Electronic Fuel Injection Technology

With the world engineering machinery, transport vehicles, such as the increase in the number of diesel engine exhaust emissions on the Earth's environment has become the main cause of pollution, how to take measures to protect human life the Earth's environment has been a priority. China from the 1980s formulated the relevant standards, environmental protection as a major task. At the same time, countries around the world have begun to seek and explore other methods and take other effective measures to reduce and control initiative pollutant emissions. Electronically controlled common rail fuel injection technology is from the numerous methods and measures in the emergence of a more successful pollution control diesel emissions from new technologies. 

Diesel Engine high-speed operation, the diesel injection process time only 1000 of a second. Experimental proof, blasting process, the pressure of the entire high-pressure pipeline is the time and location of the different change.Compressible nature of diesel in the diesel and high pressure tubing pressure fluctuations, the actual fuel pump and injector status under the law of supply plunger greater difference. Tubing, sometimes the pressure fluctuations in the jet, so that the pressure within the high-pressure pipeline rose again, reaching the injector valve opening pressure, the Commissioner will have Closed the valve and reopened the secondary injection phenomenon. Because it is impossible to burn the second injection, so an increase of smoke and hydrocarbons (HC) emissions and increase fuel consumption. In addition, each spray cycle of the high-pressure pipeline residual pressure will change, with the spray caused instability, particularly in the low-speed region prone to the phenomenon. Injection serious not only uneven, it will not happen intermittent jet phenomenon. In order to address diesel engine fuel pressure changes caused by the defects, a modern diesel engine 

As a "Common Rail" EFI technology.

1, Principle 

Generally believed that diesel engine fuel injection technology experience of the traditional mechanical manipulation of the pure-injector and modern electronically controlled fuel injection two-manipulation Development stage. Modern electronically controlled fuel injection technology rise, it is computer technology and the rapid development of sensor detection technology results. At present, the electronically controlled fuel injection technology from the initial position to control the development of time-based control. Electronically controlled common rail fuel injection technology is based 

Belong to the latter. 

EFI common rail technology refers to the high-pressure pumps, pressure sensors and electronic control unit (ECU) of the closed-loop system , Will be the injection pressure and injection process have completely separate from the mutual form of a fuel supply. It is high pressure will be high-pressure fuel pumps Transported to the public for the pipeline, through public for the hydraulic tubing to achieve precise control, high-pressure tubing pressure and engine size 

Speed has nothing to do, can be drastically reduced diesel engine oil pressure with engine speed changes in the extent, therefore, will reduce the traditional Diesel flaws. ECU control the injector fuel injection quantity, and its size depends on fuel orbit (public for tubing), and pressure Magnetic valves open the length of time. The technology is no longer the traditional piston pump pulse of the principle of supply, but by directly or indirectly for rail To the formation of a constant high-pressure fuel delivered to each injector, and the help of integration in each injector on the high-speed electromagnetic switch Valves open and close, regular quantitative control of the injector jet fuel to the engine combustion chamber, thus ensuring optimal combustion engine Burning ratio and good atomization, and the best time to get angry, at least enough energy and pollution emissions. 

2, Category 

According to the formation of different high-pressure fuel injection, electronically controlled common rail fuel injection system there are two basic types, that is, and the High Pressure Common Rail 

Pressure Common Rail. 

(1) high pressure common rail system. High-pressure pump will be delivered to common rail pressure to eliminate the pulse pressure, then delivered to the fuel injection ; When the electronic control devices as required to issue directions signal, high-speed solenoid valve (s response about 200) or open quickly Closed, thereby control the injector work, that is, according to the requirements set out Tingfen or high-pressure fuel. 

(2) pressure in the common rail systems. In the pressure pump (pressure of 10 to 13 MPa) pressure in the common rail fuel transported to the Elimination of the pulse pressure, then distributed to the plunger with a supercharger injector; when the high-speed switching valve solenoid valve receive electronic control equipment Purchase orders sent the signal, and rapidly opened or closed to control the fuel for the work quickly through a high-pressure plunger booster Use, will come in the common rail fuel pressure from the pressure of high pressure (120 to 150 MPa) emitted or Tingfen. High Pressure Common Rail Pressure in the common rail system and the system's main discrimination, access to high-pressure fuel manner different from the former high-pressure fuel pump direct, With the latter, was supercharged supercharged plunger. 

3, Features 

Common Rail Diesel Engine Electronic Fuel Injection technology-computer control technology, modern sensor detection technology and advanced fuel injector In a structure. It can not only reach a higher injection pressure, injection pressure and injection realization of control, but also to achieve pre - After spraying fuel injection and to optimize injection characteristics to reduce noise and significantly reduce diesel emissions, which is characterized as follows: 

(1) adopts advanced electronic control devices and equipped with high-speed Solenoid Valve, making the control of the injection process is the Then, and controllable parameters, to the full diesel engine combustion process optimization. 

(2) using common rail fuel supply method, the pressure fluctuations on the fuel injection system, the interaction between the injector small injection pressure control 

High precision, more accurate control of fuel injection. 

(3) high-speed, high frequency measurement-off valve, control flexibility, making the injection pressure fuel injection system of adjustable, and can Facilitate the achievement of pre-injection, after spraying, and other functions, to optimizing diesel engine fuel injection law, improve their performance and reduce emissions provided Effective means. 

(4) Structure of transplantation convenience, wide adaptation, unlike other oil hit EFI system, the structure of the diesel engine Have specialized requirements in particular the high-pressure common-rail system, with the current small, medium and heavy diesel engine and can be very good match, which the market A good prospect.