The handling and safety aspects of all road vehicles is highly dependant on correctly inflated tyres. A number of systems are in use which measure the pressure inside the tyres and transmit the information to chassis mounted receivers. Subsequent processing allows the indication to the driver of tyre deflation. Such techniques are inherently quite expensive so a system is described which monitors the inflation of the tyres with respect to each other rather than measuring absolute pressure. The technique under development relies upon the fact that if a tyre is deflated then it is rotating with a reduced rolling radius and therefore has a higher angular velocity than the wheels with correctly inflated tyres. The outputs from wheel rotation velocity sensors are processed and when one rises above a preset threshold relative to the other 3 (in the case of passenger cars), an alarm is given. Clearly there will be a difference in the rolling radius between correctly inflated tyres and therefore a tolerance band can be accepted by the driver as signifying normality before any thresholds are considered. Also there will be a difference in wheel angular velocity when cornering and an alarm condition can be avoided in this situation by cross-checking the velocities on each side of the vehicles. The system may even be implemented without applying wheel sensors if those already fitted for anti-lock brake systems (ABS) can be utilised.
Tyre deflation sensing
Fühler des Luftablassens aus dem Fahrzeugreifen
1992
6 Seiten, 4 Bilder, 3 Quellen
Conference paper
English
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