Control and operating conditions and hydrokinetic converter slip in the vehicle's transmission system

Abstract

The study concerns the slip test occurring between the pump and the turbine of automotive hydrokinetic converter. The tests were carried out on the MAHA MSR 500 test bench using a vehicle equipped with a hydrokinetic transmission ZF 4HP20 contained torque converter with adjustable lock up clutch. The paper presents the influence of the different gear change and converter control strategies as well as different load levels on the slip phenomenon between converter pump and turbine. As demonstrated by the analysis of the test results, some control strategies allow for a significant slip phenomenon, which may result in a significant decrease in the overall transmission efficiency. However, the use of an adjustable lock up clutch allows on the other hand such a control that significantly reduces the converter slip phenomenon, while blocking the pump and turbine already at low vehicle speeds can significantly affect fuel consumption, especially in the urban driving cycle.