Exhaust emissions behavior from a vehicle under road driving condition is affected by a driving force of a vehicle. It is impossible to measure the driving force by an existing torque meter under this on-road driving condition. This study reports the development and verification of the wheel torque meter which is possible to measure driving force under the on-road driving condition and has enough strength and accuracy.
The wheel torque meter developed in this study consists of a torque detector with a strain gauge type torque transducer, a telemeter receiver and a data logger. The strain gauge type torque transducer is equipped between hub and wheel at the drive axle tire, because of the narrow width of this transducer, and it is possible to be placed against vehicle without significant conversion of the vehicle. Because of these characters, this transducer is possible to be used for an on-road driving vehicle.
As a result of strength simulation of the transducer, it is clarified that its strength has been secured enough. In addition, chassis dynamometer tests of JC08 mode comparing torque measured by a wheel torque meter to the dynamo torque showed that the wheel torque meter had enough accuracy to evaluate driving torque.
Furthermore, a test course driving was carried out. In this test, the wheel torque meter has been installed to the test vehicle, which is possible to measure four driving resistances; acceleration resistance, air resistance, rolling resistance and gradient resistance. As a result of this driving test, the driving force calculated from the torque detected by the wheel torque meter was in agreement with the driving resistance value.