Research On The Lubricant Cooling System Of The Automobile's Transmission Life-span

Today hydraulic technology as one of the key basic technology to realize modern transmission and control has become an important basis that could not absence for industrial machinery,engineering construction machinery and advanced national defence production, and it is the key technology for them developing to automation,high degree of accuracy,high efficiency and high-power intensity. Since then, advanced industry nation in the world all let hydraulic industry as a industry that developed completely, and it's speed of development is higher than mechanical industry. Hydraulic component,,system and it's control has developed to a combined hydraulic project technology, it application and development is looked as an important flag to judge the level of industrialization and modernized industry of a nation. The automobile industry became the pillar industry for many nations gradually, in order to control automobile product quality strictly and enhance the quality of automobile, it's necessary to present higher and stricter request to automobile's unit assemblage and components. In this subject, we research on the lubricant cooling system of the light automobile's transmission life-span, which is basis on the horizontal development item that some factory in order to suit the development and demand of the market, further improve the quality of gearbox.I. General planning of the systemTemperature sensor is set in oil cell to monitor the oil temperature of the oil cell in this system, and let oil cell and an extrinsic cycle cooling system become an integration. When microcomputer detect that the oil temperature is too high, it will send an signal to control the flow of cooling pump, let heat of the low temperature water of cooling system and high temperature oil which lubricating the gearbox exchanged to lower oil temperature of lubricant cooling system. This system use oil constant temperature control set to realize oil temperature control of lubricant, and let lubricant flows smoothing, and then reaching better lubricated effect.Figure 1 is the schematic diagram of lubricant cooling system, hydraulic oil in oil cell is sucked in hydraulic pipeline by oil suction pump, after through out overflow valve, the hydraulic oil spurt to gearbox from relief valve and flow regulating valve, and then the oil is extracted by dump pump, at last the oil flows to oil cell after through the cooler. In order to ensure that the dump pump can not suck out all the oil of gearbox ,we set a pipeline act as a connector between oil cell and gearbox. II. Lubricant cooling system thermodynamic analysis Lubricant cooling system heat balance analysis is mainly for analyzing the performance of temperature rising of lubricating oil and the heat dissipating capacity of radiator in the heat balance system composed by gear driving heat and system's radiator, comparing to the control object to correct radiating area of radiator and adjust structural value relatedly, and providing theoretical guide for components lectotype and determining parameter.III. The hardware composition of computer control systemSince computer control system is related with the production process it controls intimately, we should adopt different control program according to complex degree and process requirement of production process. In this system, a direct digit control system is adopted by combined the specific require of test and specific test method.The figure upper is the compose schematic diagram of lubricant cooling system of experimental bench, and it can realize the function like follows:The application program collects the signal of temperature sensor and translates it to temperature value continuously. The application program compare the real temperature and set test temperature, when the real temperature of test system is not equal to the set test temperature, it use the D-value to decide the water-flow value of cooler, then it can research the set temperature exactly and quickly.IV. Software design of computer control systemThe control program of this system is developed base on the WindowsXP system, and it is the application program which base on modular programming method is compiled by C++ Builder language object-oriented.Oil temperature control of gearbox not only exist rather large time-lag and nonlinear, but also has various and special cooler, so the mathematic model is not easy to obtain, we should choice appropriate control method for the special object. In this paper three method—PID control ,Smith control and fuzzy control—are analysed and tested and the temperature fuzzy control method is adopted, and this method is emulated in Simulink. The test result indicates that the precision and stability of fuzzy control satisfy the test require.The lubricant cooling system of the automobile's transmission life-span designed in this paper has being run about one year, and it has low fail rate and high stability, it has satisfied the lubricant cooling requirement of experimental bench gearbox.