Studies on a Usage of a Limited Slip Differential Without Full Locking Features Compared to Open Type Differential and Traction Control in Mid-Size Truck - Drivers for Strategic Decision Balancing Technical Performance and Customer Perception

摘要

Basic driveline configurations offered in mid-size trucks have a standard “open” differential. Open differentials allow smooth cornering, as the outside tire must spin faster on corners as it travels a larger arc, when compared to the inner tire. This system has a main problem when traction is lost, due to slippery roads, different friction coefficients between pavements or even when the axle is submitted to a twist ditch. All of the power goes to the wheel with the least traction and the pickup is stuck. In order to improve traction on these situations, limited slip differentials were developed. A limited-slip differential will prevent excessive power from being allocated just to one wheel, and thereby keeping both wheels in powered rotation. There are several solutions offered in the market, each one presenting different torque transfer capabilities. Depending on the limited slip differential solution chosen for a determined pick-up truck, customer perception of this feature will not be considered as a value added to the vehicle. For these configurations, an open type differential with improved traction control features will provide a much better customer perception and effectiveness, as well as mass (and fuel economy) and price reductions for the product. This paper will provide some insights in order to choose traction control with open type differential instead of a limited slip differential when a pickup truck is on the early stages of its development, conciliating marketing requirements and the most effective solution to attend to the customer needs.