Design and Evaluation of an Automatically Generated Diagnosis System
Throughout recent years, legislations concerning emission levels for vehicles
have become more restrictive and will be even more restrictive in the future.
In the recent European environmental standards, EURO 4 (2006) and EURO
5 (2008), further requirements have been added on top of low emission demands.
All heavy duty trucks have to be equipped with an OBD-system.
Scania CV AB has today an existing OBD-system that consists of several
tests. Typically, a test is designed to check if a signal is inside specified limits
or thresholds. To improve the system, Scania CV AB and Vehicular Systems
at Linköping University have developed a method to design diagnosis systems
in an automatic way, implemented in a toolbox called DSAME.
In this thesis, an automatic designed OBD-system has been created with
DSAME and the corresponding parts in a manually designed OBD-system
have been identified. The two systems have been compared. The result shows
that both systems are equally at detecting faults but the automatic designed
OBD-system is a lot better to isolate the faults than the existing OBD-system.
Joakim Hansen and Jens Molin
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Last updated: 2021-11-10