|
Diesel engine with good fuel economy and reliability, and high power and durability. Compared to gasoline, since the engine is a compression ignition type, it can be a higher compression ratio and the excess air ratio of the intake throttle valve to reduce the losses to a minimum, which has a good thermal power conversion efficiency. With electronically controlled, common rail, EGR and turbocharger technology continues to improve the engine's performance continues to improve, the proportion of vehicle diesel applications to increase year by year. This test engine machine GW2.8TC-pressure common rail diesel engine, the use of second-generation Bosch common rail injection system. High pressure common rail injection system has two advantages: First, to achieve a high-pressure injection, the fuel injected into the cylinder better mixing with air, thus improving the combustion process, injection pressure and injection process generating process independent of each other, in a range not affected by the injection pressure, engine speed, load and the amount of fuel injection. Second is to strengthen the regulation and control of the fuel injection control parameters of flexibility, especially fuel injection quantity control, injection timing, injection rate and injection pressure regulator formation, etc., so that fuel injection law tends to be more idealistic. Diesel engine from the start state is a common condition. In particular, in the starting process, the body of the engine temperature is low, coolant and oil temperature is low, oil viscosity is large, will not achieve sufficient lubrication, the piston and cylinder wall so that friction increases, the above factors cylinder compression temperature, low pressure, resulting in the fuel injected into the cylinder is not very volatile, and thus good fuel vaporization, non-uniform mixture, the cylinder is easy to cause starting mixture combustion deterioration of exhaust emissions and cause increased . High pressure common rail diesel engine is also in the starting phase of the above problems, at home and abroad have done a lot of research, in order to improve the engine starting performance. By starting the engine before the test and found that it is unstable when starting the engine is running, and the emissions worse. In response to this phenomenon, the analysis and testing hardware external conditions that the engine start fuel injection control parameters are optimized to improve the starting performance of the engine. In the case of the other parameters remain unchanged, the starter fuel, main injection timing, rail pressure, pre-injection quantity and injection timing in pre Starting Condition adjusted accordingly. In order to reduce the test cycle and workload created in FIRE engine starter model, and simulation models involved in emissions do a detailed introduction. According to the orthogonal experimental design, the injection parameters as factors, the value of the selected different levels of development of a five factor 4 level orthogonal table, instead of using the 16 tests 1024 tests, analyze results of simulation emissions to HC, PM and the lowest NOx emission standards, analysis three kinds of fuel injection control parameter combinations. These three scenarios are simulated and then extract data, analyze heat release, temperature and cylinder pressure, and ultimately that starter fuel 10mg/cyc, main injection advance angle 6 ° CA, injection pressure 40 Mpa, pre-injection amount of 2 mg / cyc, pre-injection timing 13 ° CA This program makes the process of starting low emissions and improves engine power and economy. HT-LINK in the control software, the control parameters of the fuel injection MAP and coolant temperature and power supply voltage change revision MAP is optimized. In the test bench for starting the test, trial results showed that the optimal control strategy, the engine starting time is shortened, starting smooth transition to the idle speed, HC, PM and NOx emissions were decreased starting performance can be improved.
|