Direct type Tire Monitoring Systems supervise tire internal inflating pressure. NHTSA studies showed improper warnings must be avoided in order to keep the driver confidence with the system; internal temperature decrease is the Tire Monitoring Systems' main cause of improper warnings. A new approach for optimal Tire Monitoring Systems temperature compensation related to external environmental temperature, able to avoid improper warnings, will be presented. Tire Monitoring Systems main target is tire inflation state IS supervision. A warning must be sent to the driver if IS goes under a present threshold tau0, constant with temperature and closest as possible to placard inflation state IS value. The threshold value tau0, is specified as a percentage difference from nominal (or placard) inflation state Deltap. Inflation state IS supervision is possible only with a relative tire pressure sensor referring to the external absolute pressure pea, and able to detect threshold overcoming. The threshold limit tau0, must be adapted to temperature variations to better satisfy NHTSA request. The temperatures involved in the physical phenomenon are the environment external one Te and tire internal gas one, Ti. Internal tire temperature drops when the external one, Te, drops. The best temperature to take in account for the to adaptation is the external one Te, not the internal one Ti or other temperatures. The new approach proposed by the authors may solve both the problems to avoid improper warnings without decreasing safety (in any case, the threshold overcoming is immediately signaled to the driver). Furthermore, it is evident that the need of reading both external (environment) absolute pressure pea (in order to survey IS, thus tire dynamic behaviour) and external (environment) temperature Te (in order to apply an ideal threshold adaptation) shows that systems outside tire are better than the ones mounted inside tires. In case of small mass and dimensions, the outside systems may be better than the inside ones, also for safety (the centrifugal force acting on a mass placed into the tire my be very high). Nevertheless, outside mounting needs anti-theft solutions.
On tire monitoring systems temperature compensation
Die Temperaturkompensation von im Reifen eingebauten Überwachungssystemen
2004
14 Seiten, 6 Bilder, 3 Quellen
Conference paper
English
On Tire Monitoring Systems Temperature Compensation
British Library Conference Proceedings | 2004
|On tire monitoring systems temperature compensation
Automotive engineering | 2004
|On Tire Monitoring Systems Temperature Compensation
SAE Technical Papers | 2004
|On Tire Monitoring Systems Temperature Compensation
British Library Conference Proceedings | 2004
|