New technology of diesel engine, common rail, pressurization, inter-cooled - electronic control system 2015-12-27
Heavy, big noise and jet black smoke, make many people poor visual impression of the diesel engine, combined with the structure of the diesel engine is more complex, many people have a lack of understanding of diesel engine, especially the lack of the understanding of modern advanced diesel engines, diesel cars in some cities became the object of "limited", by discrimination. In fact, after years of research and application of new technology, the present situation of the modern diesel engine has been compared with the past with yu. Modern advanced generally adopts electronic control injection, common rail diesel engine and a turbocharged inter-cooled technology, in weight, noise, smoke, etc has made significant breakthrough, achieved the level of gasoline engine.
In electronic control injection is the main difference between diesel and gasoline engine, gasoline engine electronic control injection system is a control of air-fuel ratio (the proportion of gasoline and air), the electronic control injection system of diesel engine is by controlling the fuel injection time to adjust the size of the output, and diesel engine fuel injection control is determined by the speed of the engine and the throttle lever position. Basic working principle is based on computer, therefore, speed sensor and throttle position sensor of the input signal, first calculate the basic injection amount, then according to the water temperature, inlet temperature and inlet pressure of the sensor signal is fixed, and again from control set of position sensor signal feedback correction, the optimum fuel injection quantity.
Electronically controlled diesel fuel injection system consists of sensors, ECU (computer) and the executive mechanism of three parts. Its task is to the electronic control of fuel injection system, implementation of fuel injection quantity and injection timing with the operating conditions of real time control. Use the sensor such as speed, temperature, pressure, the real-time detecting parameters of synchronous input computer, comparing with the third store the values of the parameters, after processing calculation according to the optimal value of fuel pump, exhaust gas recirculation valve, such as preheating plug to control actuator, drive fuel injection system, the diesel engine operation state to achieve the best.
What is the common rail technology, why want to adopt common rail technology?
In high speed diesel engine, the high-speed operation of the diesel injection process time only a few seconds per thousand experiments show that high pressure oil pipe in the process of injection pressure is everywhere and location varies with time. Due to the compressibility of diesel oil and diesel oil in the high pressure oil pipe pressure fluctuation, the actual state of injection with those stipulated in the fuel injection pump plunger oil supply has bigger difference. Within the tubing pressure fluctuations sometimes after the main injection, the high pressure the pressure inside the tubing to rise again, to make the fuel injector needle valve opening pressure, causes have been closed needle valve and reopen the phenomenon of secondary injection, due to the secondary injection may not complete combustion, and increased the smoke and hydrocarbons (HC) emissions, fuel consumption increase. In addition, the residual pressure in the high-pressure oil pipeline after each injection cycle will change, then cause unstable injection, especially in the low speed region is easy to produce the above phenomenon, serious when uneven injection not only, and intermittent jet not phenomenon happens. In order to solve the defects of the diesel engine the fuel pressure change of the modern diesel engine USES a technology called "common rail".
Common rail technology refers to the high pressure oil pump, pressure sensor and the closed-loop system is composed of ECU, the injection pressure and injection process completely separated from each other a way of oil supply, by the high pressure oil pump for tubing, high pressure fuel to the public through the oil pressure of the public drainage tube to realize accurate control, make the high-pressure tubing pressure size has nothing to do with the rotating speed of engine, can greatly reduce the pressure of diesel engine fuel supply along with the change of engine speed, thus reducing the defect of traditional diesel engine. ECU control injector fuel injection quantity, injection amount depends on the fuel rail for tubing (public) pressure and the length of the solenoid valve open time.
Diesel engine turbocharger is familiar for you. Turbocharged inter-cooled technology is when the turbocharger to the cooler, fresh air is compressed by the middle and the intake manifold, intake valve flow to the cylinder combustion chamber. Effective inter-cooled technology can make the temperature fell to below 50 ℃, helps to reduce exhaust emissions and improve fuel economy.