Study On Desigh Theory And Control Method Of Hydraulic Retarder In Automobile

In the paper,to make a optimization design target of maximum 2,minimum response time and large scope of constant moment,the main research structure and highlights of the paper are as followed:On the basis of characteristic of hydraulic retarder,By using the time-averaged N-S equation and the standardκ-εturbulence and the SIMPLE-C algorithm simultaneously,the internal characteristics of flow field is simulated which establish the foundation of two-phrase model's initialization.The geometrical parameters is adjusted in order to obtainedλ_M and results show that the model with 36 blade number,55 degree of lean-front blade and oval section recycled circle has the biggest braking impact.Stress of an actual three dimensional blade is analyzed with digitization model which obtain AM o According to the structural feature of hydraulic retarder,pressure distribution is obtained by using coordinate transformation and surface fitting,which vary with x-coordinate and y-coordinate in local coordinates.Pressure loads are loaded on the FEA model by compiling program with APDL.Noted moment and speed is determined under the promise of blade strength,and controlling strategy is made that noted braking moment is carried out when speed is higher than noted value.The two-phase flow of the partially filled in the hydraulic retarder is simulated by using the Mixture multiphase model.The experimental data is analyzed and compared with the numerical results,which show that variation of volume fraction effect the pressure drop.With the analysis results in full-filled condition,the braking torque control model is built by normalization method.Gas pressure controlling system which electromagnetic proportion valve is adopted meet the requirement of rapid response,while working principle and controlling method is discussed.The mathematic model of united braking system is set up which involved the hydraulic retarde and primary braking device.Simulink software is employed to analyse the simulation of emergency braking,nonemergency braking and contionous braking, especially using S function to simulate constant speed during downhill. The major innovations in this paper are as follows:(1) The interface between rotator and stator is defined as interior boundary in hydraulic retarder which effectively solve the problem of fluid flow in and out in the same plane.The internal characteristic of flow field is simulated and the method of loss analysis is proposed in order to make analysis furthermore.(2) Indicate that why the experiment data of air blass loss is larger than numerical result is that there are a few liquid oil not purely air in the flow field,in addition to the mechanical friction loss in driveline(3) Indicated that braking essential reason to the hydraulic retarder is that the more intensity of vortex,the more capacity of braking performance,and the method of analysis is proposed which mass-average helicity is used to compare the retarder ability.(4) Stress of an actual three dimensional blade is analyzed with digitization model, in which the stress and strain distribution of impellers are discussed in detail.It is noted about the calculation that not only the centrifugal load but also the flow load resulted from the 3D numerical simulations of the flow field of the blade are considered.By using coordinate transformation and surface fitting,pressure loads are loaded on the FEA model according to ANSYS Parametric Design Language to realize the data transformation in liquid-solid coupling.(5) The two-phase flow of the partially filled in the hydraulic retarder is simulated by using the Mixture multiphase model and indicate that volume fraction is in functional relationship with pressure drop and the braking torque control model is built by normalization method.