refers to a high pressure common rail technology is a closed loop system by the fuel supply means in a high-pressure pump, pressure sensor and the ECU consisting of the injection process and the injection pressure is generated entirely separated from each other by the high pressure pump to the high pressure fuel delivery common rail, by enabling precise control of the oil pressure in the common rail, the rotational speed of the high-pressure rail pressure irrespective of the size of the engine, the diesel engine can be greatly reduced oil pressure with engine speed changes and, therefore, to reduce the traditional defects in diesel engines. ECU controls the amount of fuel injection injector, the fuel injection amount depends on the fuel rail (common rail) pressure and length of time the solenoid valve is open.
1 high pressure common rail noun
refers to the high pressure common rail technology is a closed loop system the high-pressure pump, pressure sensor and the ECU consisting of, the injection pressure of the injection process and produce another one way to completely separate the oil from the high pressure pump to delivery high-pressure fuel to a common supply pipe, to achieve precise control of the oil pressure within the common rail, the rotational speed of the high-pressure rail pressure irrespective of the size of the engine can be greatly reduced diesel oil pressure with a small change in engine speed and, therefore, to reduce the traditionalDefects in diesel engines. ECU controls the amount of fuel injection injector, the fuel injection amount depends on the fuel rail (common rail) pressure and length of time the solenoid valve is open.
2. The common rail diesel fuel injection system and the system
In a common rail system before the diesel injection system driven by the camshaft is different from the common rail type diesel injection system generated injection pressure and injection process completely separate from one another. Solenoid valve controlled injector replaces the traditional mechanical injectors, the fuel pressure in the fuel rail is generated by a radial piston high pressure pump, the rotational speed of the engine regardless of pressure, can be set freely within a certain range . Common rail fuel pressure regulating valve controlled by a solenoid pressure to the pressure regulator according to the continuous operation of the engine. The electronic control unit acting on the pulse signal controls the fuel injector solenoids of the fuel injection process. It depends on the length of the fuel injection quantity, and the liquid flow characteristics injector fuel rail and the oil pressure of the solenoid valve opening time.
fuel injection pressure is an important indicator of a diesel engine, because it is linked with the engine power, fuel consumption and emissions. At present, the common-rail diesel injection system, fuel injection pressure has been increased to 1800 bar.
3. The action of the high pressure common rail
provide a high-pressure pump delivering fuel to a common supply pipe, by controlling the fuel injection injector directly into the cylinder. The high pressure common rail injection process and completely separate from the hydraulic pressure generator, so that the oil pressure is not affected by engine speed.
advantages:
● high pressure common rail injection system, a flexible adjustable, can determine the optimum injection pressure required for different conditions, so as to optimize engine performance.
● When the flexible independently controlled fuel injection, with a high injection pressure (120MPa ~ 200MPa), can control NOx and particulates (PM) in the smaller value, in order to meet emission requirements.
● Flexible control injection rate to achieve the desired injection rate, easy to implement pre-injection and multi-injection diesel engine can reduce the NOx, but also ensures excellent power and economy.
● controlled by a solenoid valve injectors, high precision control, the high pressure oil passage and the bubble does not occur in zero residual pressure and, therefore, within the operating range of the diesel engine, a small change in the amount of fuel injection cycle, each oil tank uniformity can be improved, so as to reduce engine vibration and reduce emissions.
4. The characteristics of high pressure common rail
The main characteristics can be summarized as follows:
was used directly in a common rail high-pressure injection chamber, pressurizing mechanism within the injector omitted; common rail and the high pressure chamber is a continuous, high pressure pump drive torque required is much smaller than conventional pumps.
by a pressure regulating solenoid valve in the high pressure fuel pump, a common rail hydraulic pressure chamber can be flexibly adjusted according to engine load conditions and the requirements of economy and emissions, in particular to optimize the speed performance of the engine.
is controlled by a solenoid valve on the injector injection timing, fuel injection and the injection rate, also under different conditions can be flexibly adjusted after the pre-injection and the fuel injection and the injection interval and a main injection.
Common Rail System consists of five parts, i.e. high-pressure pump, a common rail high-pressure chamber and tubing, the injector, the electronic control unit, various types of sensors and actuators. Fuel supply pump from the tank is pumped into the high pressure oil inlet of the oil pump, an oil pump driven by the engine to a high pressure common rail into the fuel pressurization chamber, and then a solenoid valve controlled injector fuel injection of each cylinder at the appropriate time.
pre-injection prior to main injection, a small part of the fuel injected into the cylinder, the cylinder in the ignition delay period occurs or partially premixed combustion, the main injection is shortened. Such peak cylinder pressure rise rate and pressure will drop, more relaxed operation of the engine, while the in-cylinder temperature is reduced such that NOx emissions reduced. Preliminary ejection may also reduce the possibility of fire, improve cold start performance of the high pressure common rail system. Main injection to reduce the initial injection rate, the ignition delay period can also reduce the amount of oil injected into the cylinder. Main injection rate increase mid, injection time can be shortened to shorten the slow combustion of the combustion in the engine more efficient completion of crank angle range, increased power output, reduced fuel consumption, reduced soot emissions. Quick-disconnect end of the main injection can reduce the incomplete combustion of oil fuel, reducing hydrocarbon emissions and smoke.