Simulation And Design On Automobile Exhaust Heat Power Generation System

At present, our country becomes the world’s largest car-producing country and consuming country, but at the same time the vehicle also brings a series of energy and environmental problems. How to realize the energy-saving and emission-reduction has become a key problem of the automobile industry. Emerged in the1970s, automobile exhaust thermoelectric power generating system is becoming the hotspot of the major car firms and research institutions. Thermoelectric generating system can convert the thermal energy which contain in automobile exhaust gas to electrical energy, it can effectively improve the utilization of fuel rate, with a strong application prospect and a broad market space.In this article, on the basis of related research and the exiting of automobile exhaust thermoelectric generating system has the shortage of the output power is small and structure of the compact insufficient at this stage, this article researches the heat transfer process of engine exhaust gases and heat collector in the multi-field coupling conditions, providing the way to increase the temperature of collector’s surface and improving the collector’s surface temperature distribution. Based on the obove study, the overall structure of the thermoelectric generating system has been designed, which includes heat collector, cold water tank, clamping devices.Firstly, mathematic modle of the working process for the thermoelectric modle is built by means of thermodynamics theory, and the numerical calculation of the output power and thermoelectric conversion efficiency of the thermoelectric element dependence on the arm length and aspet ratio. Besides, use ANSYS Design Modle establishs the thermoelectric element simulation modle, after taking the exposure effects and non-linearity of the material into account. Besides, the simulation model of the thermoelectric element which is closer to actual working situation is established, and the theral, electric coupling analysis is done by the theral-electric, the sensitivity of thermoelectric performance caused by cantact thermal conductivity is analyzed, and the length1, cross-sectional area side length s dependence on the output power, conversion efficiency is studied. Then a new type of TEM is proposed, it contains49thermoelectic units, which output power is18.66W, conversion efficiency is5.2%.Secondly, Using ANSYS Software Design Modle establishes a geometric model of thermoelectric power generation system, after determining the boundary conditions, using Fluent software calculates the temperature,pressure, flow filed in the system. Then it compares the effect on the temperature, pressure and flow field of system system when the bypass valve opening and closing.Thirdly, in this article, it designs a voltage-stabilizing circuit with a stabilizing voltage chip XL4016and designs a charging circuit of lead-acid battery of12V/7Ah with the special charging chip UC3906. Using STC12C5A60S2designs a temperature control circuit, which can open or close the bypass valve depend on the given temperature.