Novel dynamic conditioning unit for the reproduction of real driving conditions on a test bed

Abstract

The importance of thermal management has increased with the advent of electrification and fuel cell. The dynamic response required from the thermal circuit has also increased and cannot be reproduced by today’s conditioning systems. This contribution describes a novel, considerably more powerful conditioning concept with three main characteristics:

• The positioning of the control actuator on the side of the unit under test without causing changes in the hydraulic circuit. The exchange of heat in this configuration occurs through mixing.

• Model-based control including improved temperature measurement as the basis for the robust variation of fluid temperature.

• A small and compact design through the consequent optimization of component location. This has the effect of further improving the dynamic response and offers great flexibility in practical use.

The new conditioning concept is validated via simulation as well as by an application on a powertrain test bed. The system proved to be extremely robust in its function due to the consideration of all influencing parameters and, in addition, it is easy to use: no time-consuming configuration work is required prior to installation, nor when changing the test bed or the unit under test. The foundation for this is the model-based control that is based on a direct relationship between the temperature of the medium and the setpoint value. For the first time, temperature traces previously measured under real operation conditions can be reproduced and even temperature gradients of up to 60 K/s can be followed. The dynamic conditioning unit described here will be extended by a transient, real-time capable simulation model to a thermal emulator. This will enable future thermal management functions to be developed and optimized in ThermoLabs.