Influencing Dynamic Handling Response with Manipulation of Advanced All Wheel Drive Systems

Trucks and sport utility class vehicles are established as choice of daily transportation in the US. A new breed of vehicles, commonly referred as “crossover vehicles”, based on passenger car derived platforms, are rapidly filling in the ranks between trucks and automobiles. Most of these vehicles are equipped with relatively sophisticated all wheel drive systems. This sophistication is necessary to fulfill the target mission of these vehicles, to provide an automatic and effortless all wheel drive capability while retaining refined on road comfort. Building on some of the existing systems and sensors, and integrating with other vehicle systems such as ABS, traction control and stability control systems, it is possible to enhance handling response by creating a moment along yaw axis. Pitch and roll movements can also be indirectly influenced. Further possibilities and enhancements will be feasible when drive by wire systems and active suspensions will become available. While most of these enhancements do not improve ultimate cornering and braking limits, they help average driver to recover or avoid critical maneuvers, improving safety and satisfaction of the users. This paper discusses several drivetrain-based approaches and concepts enhancing the on road capabilities of subject class vehicles.