Study And Design Of The Engine Turbocharged Air Temperature Controling System On Engine Testbed

Human society entered an unprecedented era of unprecedented rapid development with the emergence of car. Car has become an important component in human life. As of the popularity of cars, so many families can own their own cars.Engine give power to cars, and it is the heart of cars, The feature of engine are the components are very much , the working condition is complex, and the quality, longevity, cost and performance requirements are relatively high. This requires research and development department and production companies continue to develop and improve the engine for the market. Engine testing occupies a very important role in the engine research and development, production. It provides a lot of data for product testing, quality controlling, and so on. So the advanced engine test system provides a complete range of test tools, and has provided the essential hardware conditions for the technical innovation and theoretical study.Turbocharged engine technology makes a qualitative leap in performance. It not only improves the engine performance, but also saves energy. A company EA111-1.4TSI engine is one of the distinguished representatives. Large amount of experimental data show at the moment that the pressurization pressure keep constant conditions, when pressurized air temperature decline 10℃, it's density will increase 3 percent, at the moment that the rate of air and fuel consumption keep constant conditions, the engine's power can increase 3% in general, at the same time can greatly reduce emissions of nitrogen oxides content when we use air coolers. And engine efficiency will rise as the pressurized air temperature decrease, and inlet temperature drop per 10℃, the engine's efficiency will be correspondingly increased by about 0.5%. Therefore, it is particularly important to control intercooled temperature effectively and accurately in turbocharged engine.PID temperature controlling mode has become a very sophisticated controlling theory now, which consists of three parts: the proportion of P, integral I and differential D. The controlling methods gotten by the reasonable combination of P, I and D can gain very satisfactory controlling performance. P can produce an output signal which is proportional to the input signal, and therefore, once errors occur in the control system, the controller will take immediate effects, and make the controlled amount change toward reducing errors, and the controlling effect depends on the ratio coefficient P entirely. If it only has proportional control system, there is a big disadvantage, i.e., it can not get zero error (static error) in such a system between feedback points and set points. The existence of static error is very negative for controlling system. The best way to eliminate the static error is introducing integral control part. Controlling should vary to some trend in system because of the interference of external factors. We should effect the desired action in working part ahead of time according to pre drawn trends of the error changes. So, it can increase controlling to get quick system response, and the systems reduce in overshoot, and therefore increase the stability of the system.Turbocharged temperature controlling is a very important element for 1.4TSI engine. It can affect the integrity of launch and the accuracy of data, if it remains the previous test method in the temperature controlling, because the mechanical installation of the structure is different between 1.4TSI and 1.8T. So it become a problem to find a new controlling method.DiagRA MCD software is produced by the RA Consulting GmbH. The company is a leading German company in aftermarket vehicle fault diagnosis technology and information technology. The company has advanced software technology in OBD calibration and vehicle fault diagnosis technology. It is divided into DiagRA D ON-LINE fault diagnosis and development software, DiagRA M survey software and DiagRA C calibration software.I find that a temperature sensor is installed in the cooler by studying the cooler structure of 1.4TSI. And we can read cooler temperature , deal with them, and solve this problem by using the characteristics of the engine which can read the sensor values with communications DiagRA software and the engine ECU. ASAP has been widely recognized by many countries industry in the world. We can standardize Systematically the Data Exchange Method and software and hardware tools by this specification implementation, to reduce development costs and reducing cycle time in the vehicle electronics, to ensure quality. ASAP is created first by Germany manufacturer in 1991. Its core purpose is to provide a standard to reduce the costs that incur in global public mutual cooperation. ASAP defines a model that MCD (Measurement, Calibration and Diagnostics), establishes three criteria around the model, namely, ASAP1, ASAP2 and ASAP3. ASAP1 is the interface standard between the application layer and control equipment, and defines the physical and logical connections between the application system and the ECU. ASAP2 is standardized and standardized description, such as the ECU function, interface, calibration information, measurement information, data processing methods, and so on. ASAP3 defines the interface between the MCD system and user. It's aim is to call the standard function easily and exchange the MCD data and commands to comply measurement, calibration and diagnostic functions.The design study the automotive industry standard ASAP3 agreement in-depth. STC microcontroller read cooler temperature in real-time from DiagRA following ASAP3, compare with the set temperature, get a deviation, have a PID value from a series of projections, PID controlling output exchange into 4-20mA current loop by D /A conversion and DAC AD421, input to the Siemens flow controlling valve electronics module, adjust Cooler cooling water flow, to stabilize the control of cooler temperature.The paper is positive in engine test. It solves the key issues that the cooler temperature can not be precisely controlled for 1.4TSI. The practical application shows that the control system have safe, reliable, high stability output and anti-jamming capability advantages in the engine experiment.