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Since the introduction of electronically controlled air suspension (ECAS) systems in the nineties, no major improvements have been made in the realm of controlling air suspensions in the heavy duty truck market. Despite the lack of improvement, a need exists for intelligently controlled air suspension systems, specifically systems which can be applied to 6x2 axle configurations in the North American market. This study outlines a concept proposal for a novel suspension control concept which encompasses traction control capabilities in addition to suspension control for improved fuel efficiency benefit. The major novelty of the concept is that, by utilizing specific axle configurations and tires, a shift in pressure from the driven to the non-driven axles may result in improvements in the overall fuel economy of the vehicle.

Leaf springs are mainly used for absorbing energy associated with road outputs and they release energy coming from the road. If the complete leaf stiffness and each leaf stress distribution can be calculated carefully, while ensuring safety, required ride comfort will also be maintained. The desired vehicle ride height (attitude) under load must be taken into consideration during calculations of leaf spring design. In addition to providing the loads coming from the vehicle, leaf springs are significantly controllers of windup effects. Braking windup causes rotation at the lateral axis. When vertical F jounce load and braking moment are applied to the leaf spring simultaneously, von misses stress value on leafs will increase to a higher level which is very close to and sometimes higher than the tensile strength. The designers must ensure safety and endurance for any case during working conditions. The most critical point is front axle windup stopper position.