ABSTRACT According to the low efficiency of vehicle equipped with automotive transmission (AT) at launching conditions, the TCCs slip and lock up control technology was proposed and a TCC simulation model was established. The vehicle dynamics, torque fluctuation and efficiency were analyzed. Simulation results were obtained when taking the constant engine speed as the control target. The three-dimensional transient heat conduction finite element model using CFX was built. The slipping power was calculated and was converted to heat flux on the surface of TCCs friction plate model. The temperature of TCCs friction plate was obtained at different ATF oil temperature. Simulation results show that the TCCs slip and lock-up control technology at launching conditions can effectively solve the vehicles low efficiency problems caused by torque converter (TC). The maximum temperature rise of TCCs friction plate was 20 °C. The TCCs slip and lock up control can be carried out with the temperature of TCCs friction plate within the allowable range when the ATF oil temperature is low; The TCCs slip and lock up control is no suitable because of high temperature of TCCs friction plate which exceeds its allowable when the ATF oil temperature reaches 100 °C. INTRODUCTION The slip and lock-up control technology of torque converter lock-up clutch(TCC)[1] was almost be used for almost all automatic transmission. When TCC has tiny slipping friction rather than completely lock up, part of the engine power is transmitted by the hydraulic transmission, the other part is transmitted by the TCC mechanical transmission. The TCC closes incompletely can significantly reduce the vibration andnoise of the transmission system, and then the area of the lock-up is fully extended. When the TCC is in the slipping conditions, the slipping friction drive transmission efficiency is higher than pure hydraulic transmission due to the combined effects of hydraulic transmission and mechanical transmission, the purpose to improve the transmission efficiency of AT is achieved. However, during the TCC sliding, the temperature of TCCs friction plate will exceed its permission under the factor of sliding speed, load and friction pair structure etc. High temperature of TCCs friction plate causes friction linings burning easily or the dual steel temperature gradient over large producing warping even cracking phenomenon. The excessive thermal load of TCCs friction plate exacerbates the wear of the friction elements and thermal failure, also makes the reliability and the life of TCC getting down, and then influences the safety of vehicle operation. In order to improve the vehicle efficiency at launching conditions, the slip and lock up of TCC technology is introduced the vehicle operation. The vehicle dynamic simulation model was established. The vehicle dynamics, torque fluctuations and efficiency were analyzed taking the constant engine speed as control target. The slipping power was calculated and was converted to heat flux on the surface of TCCs friction plate. The temperature of TCCs friction plate was obtained at different ATF oil temperatures. And then the feasibility of TCCs slip and lock up control at launching conditions was verified. DYNAMIC MODLE OF VEHICLE The vehicle dynamics simulation model can be reasonably represented by 4 sub models, as show in Figure 1. The 4 sub models are engine sub model, TC sub model, transmission sub model and vehicle sub model. Slip and Lock up Control of Torque Converter clutch at Launching Conditions and Its Temperature2013-01-0357 Published 04/08/2013 Zhenjie Liu, Yulong Lei, Hongpeng Zheng and Yao Fu State Key Lab. of ASC, Jilin University Xin Jiang China FAW Group Corporation R&D Center Copyright © 2013 SAE International doi:10.4271/2013-01-0357Downloaded from SAE International by University of British Columbia, Monday, July 30, 2018Figure 1. The vehicle dynamics simulation model Engine Sub Model The engine model is based on