Suppression effect analysis of spoiler on idling loss of vehicular hydraulic retarder

To suppress the idling loss of vehicular hydraulic retarder, the suppression effect of spoiler on the idling loss was investigated by 3-D flow field numerical simulation. Based on the arrangement of spoilers, the periodic calculation models with and without spoiler installed in the stator were established to reduce the cost of simulation, and the accuracy of numerical models was verified in idling condition and oil-filling condition respectively. At different rotating speed, the calculation of idling loss was further conducted for two periodic models. The braking power applied by air was calculated in idle condition, and the distribution of velocity field and pressure field were also obtained. Then the effect of spoiler disturbing air flow and reducing idling loss was comparatively analyzed. The result shows that the spoiler can impede the air circulation flow effectively, the idling loss of the hydraulic retarder can be reduced to 48.4% at the rotary speed of 3 400 r/min, and the vehicle power utilization can be enhanced efficiently.