Simulation Study On The Matching Performance Of Heavy Vehicle And Hydraulic Retarder

City buses,heavy trucks and coaches,which were drived in the mountain area,haveto be equipped with auxiliary braking system,because the auxiliary braking system canobviously reduce the load of the service brake．Hydraulic retarder has many advantages suchas: high braking power,high brake stabilization and durable performance．So theapplications of the Hydraulic retarder are more and more wide．Presently, research ofexploitation and applications of hydraulic retarder is little, So,it is necessary to study therationality of the relationship between Hydraulic retarder and the vehicle．According to the project of"The Key Technology Research of Intelligent HydraulicRetarder of Vehicles",at the aspect of Simulation Study on the Matching Performance ofHeavy Vehicle and Hydraulic Retarder,this paper does the work as follows:Firstly, using the theory of hydrodynamic drive as the academic base,the paper studiesthe radial-blade and front rake-blade respectively．By calculating the flux and the energybalance of circulation flow of hydraulic retarder,which is namely hydraulic calculation, getthe torque characteristics of hydraulic retarder finally．Then,the similarity theory is used inthe calculation of hydraulic retarder．Furthermore,the paper also takes into account theimpact of the hydraulic retarder braking torque which from the different volume ofliquid-filled．Subsequently, the analysis of vehicle braking process on the good road whose angle ofslope isθ．The vehicle is forced by the braking torque of engine and hydraulic retarder, andby the running resistance including the air resistance and rolling resistance．During theprocess, the braking performance of hydraulic retarder and vehicle is studiedparticularly．And the ralationship between the breaking force and the adhesion acting on tirefrom ground．The dynamic analysis is the foundation for simulation model．According to the foregoing dynamic analysis, this paper uses MATLAB/Simulink to combine the vehicle and hydraulic retarder and to simulate the brake dynamic process．Thesimulation model concludes: engine module, hydraulic retarder module, air resistancemodule, rolling resistance module, the adhesion of tires module．By comparing the simulatedresult and the actual one, it shows that the error of torque characteristics of the hydraulicretarder is no more than 13%. It suggests that the model of the hydraulic retarder iscorrect．And the simulation results of brake performance of the vehicle which equips thehydraulic retarder, are prepared for the experiments which will be compared with．Then,according to GB 12676—1999"The Structure, Performance And Method ofExperiment of Vehicle Brake System", tests the brake performance of the vehicle whichequips the hydraulic retarder．Based on the test results, the simulation reaults iscompared．And the analysis of the comparation shows that the initial speed is same and thefinal speed is close to each other, the error of vehicle speed is no more than 26.9%．So thesimulation model of the vehicle which equips the hydraulic retarder could reflect the actualcondition objectively．In the end, combined with the experiment, the evaluation index and the evaluationmethod of the matching performance of vehicle and hadraulic retarder are analysed．Andbased on the simulation model,the analysis of the matching performance of the vehiclewhich equips different size hydraulic retarders(Both type A and type B have a same frontrake.Type A:outer diameter of circle chamber is 332.1 mm, and inner diameter of of circlechamber is 183.9mm; type B:outer diameter of of circle chamber is 292.8 mm, and innerdiameter of of circle chamber is 167.2 mm.), shows that on the road whose angle of slope is9%, the vehicle with type A could keep speed beteen 25.8km/h and 28km/h , compared withtype B could keep speed above 31km/h, which is too fast to run on such road. Obviously, thebrake performance of the vehicle with type A is rised 16.8% at least from the one with typeB．So it is more suitble to match the vehicle.with type A hydraulic retarder than type B．The study of the simulation and experiment of the vehicle which equips the hydraulicretarder in this paper,afford theoretical basis,technology reference and viable researchmethod for the exploitation and matching application of hydraulic retarder．...