Evaluation Criteria for AWD Vehicles System Analysis

Handling behaviour is a very important aspect of modern cars, which need to reach high levels of lateral acceleration maintaining good stability and driveability. The presence of an AWD powertrain changes the response of the vehicle and then it is very important to qualify the car behavior in terms of perceived performances through objective indexes. The paper presents the development of evaluation criteria for AWD vehicles objective assessment; simulation tools and SW standard procedure has been optimised for AWD performances virtual evaluation and different architectures (locking, self-locking, visco-coupling, active differentials) are compared in terms of longitudinal, lateral and cross-coupling dynamics performances. Through the proposed methods it is possible to make vehicle system analysis using simulation model and standard procedures to classify different AWD architectures. It is also a powerful tool for target setting-deployment-achieving in order to traduce AWD vehicle performance in terms of architecture choice and component specifications. The same criteria could be used to support control strategies development and on road AWD systems experimental tuning through simulation analysis. In the paper the application of the method to a virtual upgrade of the Alfa Romeo car is also described: the AWD layouts of interest have been simulated on the virtual car, as a support to the choices of a new Fiat platform.