Refers to high-pressure common rail technology is the oil pump, pressure sensors and ECU closed-loop system consisting of, the injection pressure generation and injection processes are completely separate from a fuel supply of forms, from high-pressure oil pump to high-pressure fuel delivery to the public for the pipeline, through the within the public for the pipeline to achieve precise control of hydraulic, so that the size of high-pressure pipe pressure and engine speed has nothing to do, you can dramatically reduce diesel engine oil pressure with engine speed changes, and hence reduce the shortcomings of the traditional diesel engine. ECU controlled injector fuel injection volume, injection volume depends on the fuel rail (public for the pipeline) pressure and electromagnetic valve is open the length of time.
Refers to a diesel engine fuel injection
Fuel pressure common rail system will generate and separate from the fuel injection, if the unit pump diesel injection diesel technology revolution than done, then it can be called a common rail rebellion, because it deviated from the traditional diesel systems similar to fuel injection system in order. Common-rail system opened up to reduce diesel engine emissions and noise of the new ways of
Europe can be described as a paradise for diesel vehicles, diesel cars in Germany accounted for 39%. Diesel cars have been nearly 70 years of history, while the last 10 years, diesel engines can be said to have rapid development. In 1997, Bosch and Mercedes co-developed the common rail diesel injection systems (Common Rail System). Today in Europe, many brands of cars are equipped with common-rail diesel engine, such as the Peugeot had HDI common rail diesel engine, Fiat JTD engines, while the Delphi Multec DCR is developed diesel common rail systems.
Common-rail system and prior to the camshaft drive of the diesel injection systems, common rail diesel injection system injection pressure generation and injection process completely separate from each other. Solenoid valve-controlled fuel injector, replacing the traditional mechanical injectors, fuel rail the fuel pressure by a radial piston high-pressure pump produces pressure independent of the size of the engine speed can be set freely within a certain range . Common-rail fuel pressure in the pressure regulator by a solenoid valve control, according to the engine requires continuous pressure regulator. Electronic control unit acting on the injector solenoid valve on the fuel injection pulse signal control process.
The amount depends on the fuel injector rail in the hydraulic and electromagnetic valve is open the length of time, and the nozzle fluid flow characteristics.
Diesel engine fuel injection pressure is an important indicator because it is linked with the engine power, fuel consumption, emissions and so on. Common-rail diesel injection system, fuel injection pressure has been increased to 1800 bar
The last 2 years, matching direct-injection diesel engine cars in Europe has been a significant development, with efficient and excellent fuel economy and reduces engine noise. Direct-injection diesel engine using a pump nozzle system, the domestic production of 1.9TDI Bora on the application of this system, the maximum injection pressure up to 1800 bar. Pump nozzle injection system, good is good, but can not maintain a constant fuel pressure, with the more stringent emission control, we need higher and constant pressure diesel injection and better electronic controls, so many manufacturers put the benefits of a more number of diesel common rail system as a diesel engine development.
The system has a high fuel pressure, and can provide flexibility for fuel distribution control and flexibility through the ECU to control fuel distribution, fuel injection time, injection pressure and injection rate. Through the control of the above characteristics, common-rail diesel engine has made the response and driving comfort has reached the level of gasoline engines, while it has a significant fuel economy and low emission characteristics.
All within the framework of the engine speed to ensure high fuel pressure, high injection pressure can get good at low speed operating conditions of combustion characteristics of
Controlled by a camshaft-driven distribution of the axial piston pump engine, fuel system pressure and a linear relationship between engine speed, engine low fuel pressure formed when the lack of speed, while the common rail system to the engine speed range within all the a very high fuel pressure. Flexible electronic control system timing and injection pressure control of a variety of operating conditions in the engine have access to low emissions and high efficiency. As the pressure injection process of the formation and separation, so that the engine designers in the study of combustion and injection procedure to obtain greater freedom. Working conditions in accordance with the requirements of regulating the engine injection pressure and injection timing,
So that the engine can be in the low-speed operating conditions to achieve complete combustion, so even in the low speed high torque can be obtained. Pre-injection technology applications in reducing emissions and noise, made even greater progress.
Precise control of fuel supply systems are
Low-pressure oil pump to suck out of diesel fuel from the tank through filters provided to the high-pressure oil pump, in the low-pressure pump has a solenoid valve controlled fuel to reach high-pressure pump chamber, the fuel enters the tube-shaped Accumulator - the fuel rail. There are the common rail pressure sensor from time to time to monitor fuel pressure, and this signal is passed to the ECU, through the regulation of traffic within the control of common-rail fuel pressure reached the desired value. Injection pressure according to engine operating conditions, different from 200 ~ 1800 bar, and through computer-controlled injection into the cylinder, respectively, the common-rail fuel pressure has not only maintained, but also eliminate the pressure fluctuations.
Fuel injection is a very complex mechanical, hydraulic and electronic systems to do a joint industry, to adapt to a variety of operating conditions the engine working environment, before burning the fuel must be filtered and pressurized, at the exact time a certain injection rate of injection into the Each one cylinder. Computer-controlled engine exhaust gas recirculation, pressurization, exhaust after-treatment system in order to get the best engine characteristics and exhaust emissions.
The smallest displacement engine and the latest generation of common rail common rail engine
The compact structure makes injector common-rail system, even for small-displacement four-valve engine is a useful program. At the end of 1999 gave birth to assembling the three-cylinder common-rail diesel engine of the Smart, its displacement is only 799mL, Maximum Power 30kW, in the 1800 ~ 2800rpm when the maximum torque output of 100Nm.
Introduced this year, Mercedes-Benz E320 is installed on a second-generation common-rail engine, maximum power of 150kW, 1000rpm, when the output torque of 250Nm, at 1400rpm Peak torque can be obtained when the 85% in 1800 ~ 2600rpm within the broad area peak torque of 500Nm. 0 ~ 100km / h acceleration time of only 7.7 seconds, top speed 243km / h. Integrated fuel consumption is 6.9L/100km, 80L fuel tank capacity of making life a 1000km. The E320 is equipped with gasoline engines in the combined consumption is 9.9L/100km.
Diesel common rail system has developed three generations, it has a strong technical potential
First-generation common rail high-pressure pump is always kept at maximum pressure, resulting in energy waste and high fuel temperature. Second-generation needs to change according to the engine output pressure, and has the pre-and post-injection spray features. Pre-injection to reduce the engine noise: in millionths of seconds before the main injection a small amount of fuel is sprayed into the cylinder compression-ignition, pre-heat combustion chamber. After preheating the cylinder so that after the primary injection compression-ignition easier, the cylinder pressure and temperature is no longer a sudden increase is conducive to reducing combustion noise. In the expansion process in the post-injection, resulting in post-combustion, will increase the cylinder temperature of 200 ~ 250 ¡æ,
Reduce the exhaust of hydrocarbons.
Because of its strong technological potential, today of all manufacturers have their sights set at the 3rd generation of Common Rail System - piezoelectric (piezo) common-rail system, piezoelectric actuators instead of the electromagnetic valve, so get a more accurate Injection Control. There is no return pipe to the structure easier. Pressure from 200 to 2000 bar flexible adjustments. The minimum injection quantity can be controlled in 0.5mm3, reduces smoke and NOX emissions.
"Electronic control" refers to the fuel injection system controlled by computer, ECU (commonly known as computer) for each nozzle of the injection volume, injection timing for precise control, enabling diesel engine fuel economy and dynamic to achieve the best balance of , whereas the traditional diesel engine is by mechanical control, control accuracy can not be guaranteed.
"High" refers to the traditional diesel fuel injection system of higher pressure than 3 times the maximum can reach 200MPa (and traditional diesel fuel injection pressure is 60-70 MPa), pressure and better atomization fully burned, thereby increasing power, ultimately achieve the purpose of fuel-efficient.
"Common Rail" is a pipeline through the public for the same time, the supply of all fuel injectors and fuel injection ECU precise calculation of the amount over the same time, each injector to deliver the same quality, the same pressure fuel to make the engine run more smoothly, to optimize overall performance diesel engines. The conventional diesel engine fuel injection by the respective cylinders, fuel injection volume and pressure are inconsistent, uneven running, resulting in combustion is unstable, noisy, fuel consumption high.
Now, the domestic manufacturing with international advanced technology, electronically controlled high pressure common rail diesel engine diesel engine used the latest core technology, Europe and the United States, obviously superior to conventional turbocharged diesel engine. Than the conventional turbocharged diesel engine combustion efficiency increased by 8%, 10% lower carbon dioxide emissions and noise decreased by 15%, completely changed the engine in people's minds, "noisy, black smoke" image.