Diagnosis of a compressed air system in a heavy vehicle
Compressed air has in the past been considered as a free resource in heavy vehicles.
The recent years work to minimize fuel consumption has however made air
consumption an interesting topic for the manufactures to investigate further.
Compressed air has many different applications in heavy vehicles. One important
consumer of compressed air is the brake system, which would not work at all
without compressed air. The compressed air is produced by a compressor attached
to the engine. A leakage in the system will force the compressor to work longer,
which leads to an increased fuel consumption.
It is of large interest to have a diagnosis system that can detect leakages, and if
possible also provide information about where in the system the leakage is present.
This information can then be used to repair the leakage at the next service stop.
The diagnosis system that is developed in this thesis is based on model based
diagnosis and uses a recursive least mean square method to estimate the leakage
area. The results from the validation show that the algorithm works well for
leakages of the size 1-10 litres/minute. The innovative isolation algorithm gives
full fault isolation for a five circuit system with only three pressure sensors.
Martin Kågebjer
2011
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Senast uppdaterad: 2021-11-10
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