Transmission Fluid Properties’ Effects on Performance Characteristics of a Torque Converter: A Computational Study

Abstract

The impact of the viscosity and the density of transmission fluids on the performance of a hydraulic torque converter was examined. Four different transmission fluids were evaluated under different operating conditions by fluid temperature and speed ratio. The study utilized the computational fluid dynamics (CFD) method, which modeled the transmission fluid as an incompressible and Newtonian fluid and simulated the flow field inside the torque converter by numerically solving the governing equations of the fluid flow. The simulated flow fields of four different fluids were examined via mechanical performance parameters of the torque converter, including the k-factor and the efficiency. The transmission fluids were also experimentally evaluated using the modeled torque converter at two independent laboratories. Comparisons of the model predictions with the experimental results showed that the computational data agree well with the test data. A parametric study was performed by using the validated CFD model. The results indicate that the viscosity and density of the fluid have opposing effects on the performance of the torque converter studied.

Keywords:

• Torque converter performance
• transmission fluid properties
• computational fluid dynamcis

Funding

The first two authors gratefully acknowledge support by Western Michigan University’s Center for Advanced Vehicle Design and Simulation (CAViDS).