Pressure sensor monitors nine wheels

Edited by the Engineeringtalk editorial team Jan 17, 2008

BERU F1 Systems' motorsport experience, gleaned from rally, desert and endurance applications provided the knowledge to deliver a robust solution.

BERU F1 systems has created a customised tyre pressure and temperature monitoring system (TPMS) for Prevost, a division of the Volvo Bus Group.

The robust and reliable solution offers minimum complexity in component composition and configuration.

"Prevost vehicles have nine wheels (eight wheels in contact with the road and one spare), all of which must have temperature and pressure monitored", says James Shingleton, Senior Engineer at BERU F1 Systems.

"This means that positioning of antennae on the vehicle is critical to ensure good system radio frequency (RF) reception for every wheel and hence performance of the system".

"On cars, we normally mount antennae on the floor of the vehicle", continues Shingleton.

"However, the structure of the Prevost coach is a complex framework, which inherently means that antennae are located in quite shielded locations".

"Some systems would struggle to achieve good RF reception there but the BERU F1 Systems antennae achieve such excellent RF performance that only three antennae are required to monitor all nine wheels".

In addition to good RF reception, which BERU F1 Systems originally developed the system for Formula One cars so that only one antenna is required per axle.

The antennae must also include sufficient protection against exposure to the physical elements.

Snow, grit and also heat generated by the engines create a harsh operating environment.

BERU F1 Systems' motorsport experience, gleaned from rally, desert and endurance applications provided the knowledge to deliver a robust solution.

Despite the obvious differences in vehicles, the Prevost coaches do exhibit some similarities with high-performance cars.

"During testing we were surprised to find wheels on some Prevost coaches reaching temperatures of up to 100C", says Shingleton.

"Our system has no problem operating at these temperatures as they are well within the operating limits of our wheel sensors".

Integration of the TPMS into the vehicle's CAN architecture is another crucial phase in the system development and requires extensive testing that can be costly.

In this instance it would have been impractical to achieve using a standard bench system as the software engineers would have to repeatedly inflate and deflate all nine tyres.

"Specifically for Prevost, we developed a cost-effective simulation mode within the TPMS control unit that is able to simulate all the wheels and activate all possible warnings generated by the sensor", explains Shingleton.

"This speeds up the system integration process considerably and is a much more manageable method, with no wheels cluttering up the test centre".

During the two-year development cycle of the TPMS system, the physical distance between BERU F1 Systems in the UK and Prevost in Canada presented BERU F1 Systems with the opportunity to develop a further problem solving product.

Truck Tyre PC, the software that works with the TPMS is user friendly and makes it very simple for Prevost to reconfigure the ECU, try new settings and log data, which can then be emailed back to BERU F1 Systems for analysis.

BERU F1 Systems is now working with Prevost to extend the TPMS application to monitor the wheels on coach trailers.