Temperature estimation of CHV brake discs using an energy balance approach

This paper is concerned with the brake discs temperature estimation of commercial heavy vehicles (CHV). The estimation methodology is motivated by the difficulty to find and to implement a convenient sensor. Moreover, an estimation module allows not only to give the online value of the temperature but also to predict the temperature under a given set of data concerning the vehicle and its environment (road profile for instance). Using this prediction, it becomes possible to develop a complete automated braking strategy under safety criteria. Our approach lies on the global energetic balance of the truck in motion. The main idea is to express the thermal energy that the disc stores when a braking action is performed. In order to express this energy, the global system that influences the slowing down of the vehicle has to be considered. This system is composed by the following technical braking components: brake discs, transmission retarders (hydraulic or electromagnetic), controlled engine brakes and exhaust brakes. The mass, the shape of the vehicle (equivalent surface) and the road profile, are other parameters that directly influence the slowing down of the vehicle and that have to be taken into account. We present here our general methodology to achieve the estimation goal and some real life tests results. These tests, realized on a prototype truck: Renault Trucks Magnum E-Tech, validate the methodology.