Design And Optimization Of Linear Motor Based Total Cylinder Sampling System

Along with the appearance of the internal combustion, human society comes into the era of automobile. Although the human being's society has been made such progress because of the development of world's automobile industry, at the same time air pollution by vehicles is more and more serious. Diesel engines have been widely used because of its high power density, low fuel consumption, and high work reliability, the mostly attention have been paid on its particulate emissions. With the incremental retention of diesel vehicle in these years, the serious air pollution caused by diesel vehicle must be regarded. With more stringent emission regulation the lower exhaustion become to the target for diesel vehicle manufacturer pursuing all over the world.Engine's power, economy and emissions characteristic of its combustion process is closely related to the combustion process. Thus transient conditions of the combustion engine, emission characteristics and performance improvement has become the focus of the study. An important way to control emissions is to study the creation behavior of pollutants through combustion process of diesel engines.These techniques include in-cylinder sampling,optic measurements,CFD (Computational Fluid Dynamics),and so on.Total cylinder sampling system can open the combustion chamber and collect most of the mixture,which contain lots of quasi-steady reactants, under certain crank angle.Therefore,it's useful for making clear the chemical kinetics of combustion and pollutants emission of diesel engine.Total cylinder sampling system is of inherent advantages as following:1) Good sampling time-resolution2) Adequate sampling gas3) Better integral characteristic4) Consistent with exhaust gas analyzed results5) Suitable for simulation models verifying and in-cylinder particulate matter formation researching of diesel engineThe sampling mechanism is the key of total in-cylinder sampling technique. All total in-cylinder sampling techniques can explore the cylinder diesel engine of harmful pollutants formation mechanism, formation process and the factors affecting an effective research tool. However, the previous sampling system use cones knife, membrane-disruptive as the main structure. It must be re-installed after each sampling; testing time is a long time cycle. It is difficult in the short term to complete the same test conditions. The result of sampling dispersion is larger, and affecting the accuracy of research.This paper follows a linear motor controller as a major sampling and the entire sampling cylinder body design.Research and development of the electronic total sampling system, and applied simulation sampling process, And done a sampling of their dispersion studies and have achieved good results.In the foreseeable future can be used in real-wide gas engine Cylinder sampling.In this paper, complete the followings:1. The mechanism of total cylinder sampling technology and the method of studying the chemical kinetics of pollutant emissions forming during the in-cylinder combustion process of diesel engine have been described. The feasibility of studying the combustion kinetics of diesel engine under transient operations has been discussed and verified. The typical sampling mechanisms have been analyzed and the most important shortage of these kinds mechanism being of the sampling-timing decentralization. Above all, the demands of novel sampling system have been founded out based on the thoughtful analysis of existent systems.2. Application of linear motor is designed to replace all mechanical parts of the electronic transmission of the total sampling system. And its main components were introduced and illustrated. Its work processes, design, system components, control strategy and other issues were specificly analysised. And in accordance with the requirements of the actual sampling, has made use of electronic pulses to trigger linear motor tests. MSC51 microcontroller design based on the procedures will use for determining the circle and reading a few of the Z trigger pulse signal.So that the actual sampling can be used in the engine angle device to trigger pulse Z phase linear motor.3. Through learning about the linear motor, setting up their parameters of the initial installation and debugging, including phase, current loop, velocity loop, and position loop and so on.Using Application of XenusTM driver and functions Of CVM's (Copley Virtual Machine) internal controller to set up the controlling way of stand alone as well as to configure the speed of movement and other issues of the system debugging.4. Designed and established the electronic total cylinder sampling system simulation test platform. The sampling history of simulative cylinder has been gained by home-made testing bench at home temperature. Test results show that more than 80 percent in-cylinder gas will out-let within 3.4ms,when the initial cylinder pressure 7.5 MPa to 5 MPa ,which means quick response characteristic and feasible to adopt in engine testing.Using the rapid response characteristics of photoelectric switches and high-speed data acquisition card to measure the time-discrete of total sampling system. After sampling the response dispersion test and analysis of data, the result shows that the whole system dispersion of sampling is 5.7ms.It is much larger than ever mechanical systems.Therefore, the system must be improved.5. We discussed the reasons of dispersion. For these reasons, we designed the way based on electronic pulse signal as a controlling signal to control the linear motor.So that the internal I / O trigger changes into the form of a fixed frequency pulse to control linear motor's moving. That is called external trigger mode. Adopt the approach will be greatly improved electronic sampling system's dispersion.6. Under the existing test equipment we improved the electronic sampling system, and improving test done. Through the results of experiments show that the time dispersion reduced from 5.7 ms to 3.44 ms.The system has been close to the traditional tube knife cutting diaphragm and collision-sampling agencies. And the future research work can be greatly improved, as well as reducing time dispersion.Then the system could actually use of sampling.