Simulation of Heavy Commercial Vehicle Response to Rear Super Single Tire Blow Out

The fuel economy of heavy commercial vehicles can be significantly improved by reducing the rolling resistance of tires. To reduce the rolling resistance of 6×4 tractor, the super single tires instead of rear dual wheel tires are tried. Though the field trials showed a significant increase in fuel economy by using super single tires, it posed a concern of road safety when these tires blowout during operation. Physical testing of tire blowout on vehicle is very unsafe, time consuming and expensive. Hence, a full vehicle simulation of super single tire blowout is carried out. The mechanical properties of tires such as cornering stiffness, radial stiffness and rolling resistance changes during the tire blowout; this change is incorporated in simulation using series of events that apply different gains to these mechanical properties. Various scenarios like super single tire blowout during straight road driving or taking loose/tight turn, blowout of leading/trailing rear axle super single tire are simulated for a tractor-semitrailer vehicle. It has been found from results of simulation that the vehicle pulls on the side of tire that is blown. The vehicle deviation from the desired path is comparatively more during a high speed cornering than while driving on a straight road. Also during the blowout of tires on a straight road, the vehicle can be controlled with a small driver steering correction. However, when the outer super single tire blow-out happens while vehicle cornering, the path deviation is more and in case of tight turns the panic sharp steering correction from driver induced a high lateral acceleration which resulted in a rollover of the vehicle. Thus, super single tire blowout during high speed cornering can make the vehicle unstable and thus dangerous to road safety.