FVA 671/III – Drag torque calculation II

Calculation and Investigation of the Drag Torque of Wet Multi-plate Clutches

Research Topic

Short Title	Drag torque calculation II
Start of Project	Q1/2022
Funding	FVA-Nr. 671/III Research Association for Drive Technology e.V., FVA
Contact	T. Schneider, M.Sc.; Dr.-Ing. K. Völkel

Project Description

Wet disk clutches are crucial components in automotive, marine and industrial drivelines. In the open condition, load-independent drag losses caused by fluid shear occur. If several open clutches are present in a transmission, their drag losses can represent a significant proportion of the total losses. The aim of development is to reduce these losses. In the research project FVV 1012 a large number of influencing factors were examined in their effect on drag losses in extensive test series. In the follow-up project FVA 671 I, the knowledge about drag losses and their formation mechanisms was expanded. In the research project FVA 671 II an empirical-mathematical model for user-oriented drag torque calculation was developed on the base of experimental investigation results. With the derived model it is now possible to calculate the drag torque in the early stage of clutch-development with minimum computational effort and at sufficient accuracy at the same time.

Classification of the model compared to existing analytical models and CFD models.

To increase the reliability of the calculation, however, a targeted expansion of the underlying data bases is absolutely necessary. The aim of the research project is thus the further development of the empirical-mathematical calculation model. To this end, the existing databases for clutch operation mode at injection lubrication and dip lubrication must be expanded by means of systematic test series. In addition, factors such as the inclination of the rotational axis, air content in the oil and disk movement on drag loss behaviour are to be investigated experimentally. Furthermore, the potential of spacer elements will be evaluated. In addition to model optimization selected findings from the project will be incorporated as an extension into the user interface developed in the project FVA 671 II. Thus, a direct transfer of current research results to the companies will be realized.