Torque and Temperature estimator for an AWD clutch

1. Background
General Motors global development center for all-wheel drive (AWD) applications on frontwheel
drive based vehicles, is placed at Saab Automobile in Trollhättan. The development
activities cover both hardware and control software development. We have a clear mission
to establish world leadership within AWD technology.
The AWD system is an enabler for enhanced vehicle dynamics performance by controlling
the wheel torque for optimized traction, stability and take-off performance.
For efficient control and hardware protection, an estimation of the transferred torque and
clutch temperature is required.
2. Objective
The objective is to establish a model and method to estimate transferred torque and
temperature in the AWD wet lamella clutch based on accessible input signals, e.g. applied
pressure to the lamella pack and relative slip over the coupling. Ambient temperature is
available at the front of the vehicle, however not near the clutch itself.
The estimates will be used as input signals to the torque control model. Since the physics
of a certain coupling is complex and even unknown a partly empiric approach to derive the
model is preferred.
The development environment will be Matlab/Simulink
Our proposal is to split the task into 2 master theses:
2.1. Torque estimator for an AWD clutch – creating a transfer function from clutch
pressure to holding torque
2.2. Temperature estimator for an AWD clutch – creating relations between heat
energy input and clutch and oil temperature by combining physical and empirical
relations for the clutch and installation environment
We prefer if each thesis is conducted by 2 students. The work can be started Jan 2008.