Views:4 Author:Site Editor Publish Time: 2020-04-17 Origin:Site
Fuel injection pressure is an important indicator of diesel engines
Fuel injection pressure is an important indicator of diesel engines because it is related to engine power, fuel consumption, emissions, etc. The common rail diesel injection system has increased the fuel injection pressure to 1800 bar
In the past 2 years, cars with direct injection diesel engines have developed significantly in Europe, with high efficiency and excellent fuel economy, and reduced engine noise. The direct injection diesel engine uses a pump nozzle system. The domestically produced 1.9 TDI Bora uses this system. The maximum injection pressure can reach 1800 bar. Although the pump nozzle direct injection system is good, the fuel pressure cannot be kept constant. With the more stringent emission control, higher and constant diesel injection pressure and better electronic control are required, so many manufacturers take advantage of Many diesel common rail systems are the development direction of diesel engines. This system has a high fuel pressure and can provide flexible fuel distribution control. The ECU flexibly controls fuel distribution, fuel injection time, injection pressure and injection rate. Through the control of the above characteristics, the common rail has made the diesel engine's responsiveness and driving comfort reach the level of gasoline engines, while it has significant fuel economy and low emission characteristics.
Ensure high fuel pressure in all engine speed ranges, high injection pressure can obtain good combustion characteristics under low speed conditions。
In an engine with an axial piston pump controlled by a camshaft, the fuel system pressure is linearly related to the engine speed, resulting in insufficient fuel pressure at low engine speeds, while the common rail system can achieve very High fuel pressure. The flexible electronic control system controls timing and injection pressure to achieve low emissions and high efficiency under various engine operating conditions. Because the pressure formation is separated from the injection process, engine designers have greater freedom when studying combustion and fuel injection processes. The injection pressure and injection timing can be adjusted according to the requirements of the engine operating conditions, so that the engine can achieve complete combustion under low-speed operating conditions, so it can obtain large torque even at very low speeds. The application of pre-injection technology has made greater progress in reducing emissions and noise.