|Diesel Engine Electronic Control Technology|
Bulky, noisy, smoky, so many people are poor impression Diesel intuitive, and more complex structure Diesel, and many people lack an understanding of the diesel engine, particularly on modern art diesel lack of understanding. In fact, after many years of research and application of new technologies, the situation has been in modern diesel engine with the same metaphor of the past. Modern diesel vehicles generally use EFI, common rail, turbocharged technology in the cold, the weight, noise, smoke and other major breakthrough has been made to the gasoline engine level. At present foreign Diesel light-duty vehicles has become increasingly popular, Mercedes-Benz, Volkswagen, BMW, Renault, Volvo, and other European brand cars have diesel engine models.
EFI in the area of diesel and petrol are the main differences between gasoline machine EFI system is air-fuel ratio control (the ratio of air and gasoline), diesel EFI system by controlling the fuel injection is time to adjust the size of the output, and the diesel engine fuel injection engine control by the speed and accelerator pedal position (drawbars throttle position) to decide. Thus, the basic principle is the basis of computer speed sensor and throttle position sensor input signals, first calculate the basic fuel injection quantity, and then under water temperature, inlet temperature of the air pressure sensor signal amendment, and again from the control sets Position sensor signal feedback amendment, to determine the optimum amount of fuel injection.
Electronic diesel injection system consists of sensors, ECU (computer) and the implementing agencies composed of three parts. Its mission is to electronically controlled fuel injection system, fuel injection volume, and the realization of the injection timing with the operating status of the real-time control. Using speed, temperature, pressure sensors, real-time detection parameters will be entered into the computer simultaneously, and had been stored values of the parameters of comparison, has been treated in accordance with the calculation of the best value on the fuel pump, exhaust gas recirculation valve, such as preheating Cypriot implementing agencies control, driven fuel injection system to achieve the best diesel engine operating status. What is the common rail technology, why should adopt common rail technology?
In the automotive diesel engine, high-speed operation of the diesel injection process only time per 1,000 seconds, experimental shows that in the process of high-pressure injection tubing pressure throughout with time and location of the different change. As diesel compressibility and high pressure tubing pressure fluctuations in diesel, the actual fuel pump and injector status under the law of supply plunger greater difference. Tubing, sometimes the pressure fluctuations in the main jet, so that the pressure within the high-pressure pipeline rose again, reaching the injector pressure to open the valve, the valve has been closed and reopened the secondary injection phenomenon, Because it is impossible to burn the second injection, so an increase of smoke and hydrocarbons (HC) emissions, fuel consumption increases. In addition, each spray cycle of the high-pressure pipeline residual pressure will change the ensuing instability arising from the jet, especially in the low-speed region prone to this phenomenon, not only serious injection uneven, but will not spray in intermittent phenomenon. In order to resolve this diesel engine fuel pressure changes shortcomings, the modern use of a diesel engine known as the "Common Rail" technology.
High-pressure common rail technology is the means, pumps, pressure sensors and closed-loop system composed of ECU, will be the selection of injection pressure and injection process in a completely separate their supply, high-pressure pumps from the high-pressure fuel pipeline for conveying to the public, Through the public for the hydraulic tubing to achieve precise control, high-pressure tubing pressure size has nothing to do with the engine speed, engine oil can be drastically reduced pressure with engine speed changes, therefore, you reduce the shortcomings of the traditional diesel engine. ECU control the injector fuel injection quantity, depends on the size of the fuel injector rail (public for tubing) solenoid valve opening pressure and the length of time.
As for the turbo-charged technology when turbocharger will be compressed by the middle of fresh air cooler cooling, and then the intake manifold, the intake valve flow to the cylinder combustion chamber. Effective in cooling technology to enable pressurization temperature dropped below 50 ¡æ, and help reduce exhaust emissions and improve fuel economy.