| Engine is the heart of automobile, which is the main cause of the impact of automobile dynamic performance and economic. Diesel engine as an important branch, has been paid more and more attention, because of good economy,high thermal efficiency and lower harmful emissions. At present, domestic and foreign trucks,large buses have been widely used in a diesel engine, of which 100% heavy-duty trucks powered by diesel engines. In order to improve the diesel engine dynamic performance and economic after the overhaul, to extend the service life of diesel engines, and to text weather the diesel engine performance after the repair is up to the required standards ,the overhauled diesel engines must be carried out for wear and performance test.Running-in is a process,which is the friction surface properties transiting from the initial state to the use of state. Ex-factory whole machine Running-in of diesel engine is divided into cold wear and hot test. Now the engine productions at home and abroad mainly take the separation way of cold wear and hot test to new assembly engine; Automotive repair business only take the way of cold wear to overhauled engine, then the engine will be gradually loaded into hot wear, there is a serious shortcoming in this way.According to the existing engine test bench and the development of measurement and control system at home and abroad, combined with the actual situation of overhaul enterprise, this paper analyze the shortcomings of the existing bench and computer monitoring and control system in the applications of automobile maintenance enterprises, try to develop a set of test bench to achieve that diesel engine completes the cold wear and hot test at the same test bench, and the develop a measurement and control system compatible with it, the main contents and conclusions are as follows:1.A test bench for cold wear and hot test System of diesel engine is designed. Combined with the needs of subject and the actual situation at the scene, the test bench and auxiliary equipments are arranged reasonablely. Through comparative analysis of the equipments and market research, considering the generality of running-bench, the main measurement and control equipments used in test bench are selected, the main performance parameters of equipment and type are determined. Auxiliary equipments including the cooling water constant temperature system,oil constant temperature systems,intercooler constant temperature,the fuel supply system and so on are designed and manufactured. In this paper, the designed test bench can fix diesel engines of different kinds and in different fixed ways, expanding the scope of application of test bench, reducing the cost of maintenance enterprises; completing the cold wear and the hot test on the same bench through the clutch switching test equipments, improves the running efficiency of diesel engines after overhaul, and is important to improve the cold wear and hot test process of overhauled diesel engines; the designed auxiliary equipments ensure a safe and stable operation of the pilot run, also ensure the accuracy and reliability of test data, at the same time low cost of design and manufacture is a certain value to the promotion.2.The specific requirements of measurement and control system of cold wear and hot test test bench are established. The working principle of the three parts including cold wear,hot test and temperature control system are described, according to the working principle and The working process, the specific requirements for the various parts of measurement and control system are put forward, including the sensor's measurement requirements and the actuators'control requirements. according to the requirements and characteristics of measurement and control system, and to the design idea of distributed control, all parts of measurement and control system projects are preliminaried designed.3.The software and hardware for cold wear and temperature control of measurement and control system of cold wear and hot test are designed. According to the requirements of Condition-Based cold wear specification, the type of torque sensor and cylinder press pressure sensor are selected. In this paper, comparative analysis for torque measurement method are carried out, phase torque measuring principle is theoretically analyzed and derivated, adopting a transmission type torque sensor based on the measurement principle of magnetic-electric phase difference ; through the analysis and comparison of the three commonly used the phase difference of measurement methods, combined with the requirements of real-time and accuracy for torque measurement system , the phase difference converted to the time difference of the number of counting to measure the torque are used, the signal shaping circuit,phase circuit,sampling circuit and counting circuit are designed, the result of the calculation are sent into single-chip processing, achieving the measurement of torque. The cylinder press pressure being he area of high temperature measurement, through analysis and research, high-temperature melt pressure sensor are adopted for acquisition and conversion circuit was designed to achieve the cylinder press pressure measurements. To the temperature measurement in temperature control system, because of the temperature measurement range is low-temperature region, PT100 temperature sensor is selected, and XTR105 chips and the signal conversion circuit are used to collection and conversion. data acquisition cards and switches controlling hardware in the measurement and control system are selected and set, and analyze the mechanism of interference of the system, the appropriate measures on the interference problem are taken to suppress.4.The cold wear part of measurement and control system software is based on the Windows platform ,using VC++6.0 to develop. The software is modular design, the system interface is friendly , the function is perfect, and the information is rich. Traditional cold wear and Condition-Based cold wear as two functions can be achieved through software, and the temperature control system is able to automatically measured and controlled. In this paper, the flow chart of the software for the whole cold wear process and temperature-controlled process are showed.5 . Measurement error in torque measurement and cylinder compression pressure measurement are analyzed, and improvements to increase accuracy and reduce errors are put forward. the data processing for torque and cylinder pressure is done, for the characteristics of torque measuring, the curve fitting method is used to reflect the instantaneous value in the process of the torque measuring, and then the maximum single-cylinder in the process is found. for cylinder compression pressure, matlab are used to 5.3 times smoothing and wavelet analysis noise processing with the collected original signal, in the way of the average circulation of more than a way of dealing with the process , the maximum of single-cylinder compression pressure cylinder is achieved. Then the received maximum of torque and pressure are put into the analysis process to determine the wear process and the wear quality. By wear tests on WD615.64/74 Steyr diesel engine, the collected test data analysis shows that the measurement and control system has met the previous measurement and control requirements, the data collected is reliable. system of diesel engine itself is a very complex wear test equipment, the current measurement and control system of the diesel engine for cold wear and temperature controlling process has been achieved the basic purpose of the expected. Because the level of my knowledge and comprehensive abilities are limited, there is still deficient, further research work is needed to do.
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