Research On Electrorheological Fluid Fan Clutch For Commercial Vehicle

In the cooling system of commercial vehicles，the traditional fan clutches are oftendifficult to have a good cooling effect because it can’t implement continuous control, whichwill lead to a series of problems such as engine overheating, additional fuel consumption,harmful emissions and so on. These problems will be disadvantageous to the operations ofcommercial vehicles. Combined with a pre-research project "The research and developmentof new fan clutch for commercial vehicles", this paper proposes a new fan clutch based onElectroheological (ER) fluids and researches its working principle, structure design andcontrol strategy. The main research contents are as follows:Firstly, this paper discusses composition, characteristics and working requirements of ERfluids for fan clutch and analyzes its mechanical properties and influence factors. Comparingthe different ER fluids, it selects chromium-doped TiO2ER fluid as working medium of thefan clutch. It obtains relationship between its shear stress and electrical field strength bybench performance test, which will provide the technical precondition for the later study.Secondly, this paper discusses the characteristics and work requirements of fan clutch forcommercial vehicles. Comparing the transmission characteristics of parallel disc andconcentric cylinder ER fluid fan clutch, it adopt concentric cylinder in the design scheme.Then it designs transmission mechanism, supporting parts, insulation and sealing of ERfluids fan clutch and calculates its limit torque. The calculation result shows the designed ERfluid fan clutch can meet the work requirements of benchmarking commercial vehicles.Thirdly, this paper makes the control strategy of ER fluid fan clutch with the coolanttemperature as main control parameters. Moreover, it develops the Fuzzy-PID controller offan clutch by taking temperature deviation and its change rate as input variable and controlvoltage as output variable. In order to get better control effect, it adopts the Gaussian function to describe the temperature deviation and the control voltage and the trigonometricfunctions to describe the rate of temperature deviation change.Finally, this paper builds the combined simulation model with MATLAB/Simulink andAMEsim in the light of the aforementioned control strategy and Fuzzy-PID controller of fanclutch. The combined simulation model mainly contains control model of the ER fluid fanclutch and the cooling system model. The simulation results of the typical workingconditions verify the effectiveness and practicability of control strategy and Fuzzy-PIDcontroller of fan clutch in cooling system.In conclusion, the research of this paper has certain theoretical significance and practicalvalue for improving the working performance of fan clutch in commercial vehicle. It is alsohelpful to promote the technological level of commercial vehicle and expand the marketapplications of ER fluid.