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The increasing importance of reducing greenhouse gas emissions and the ongoing evolution of vehicle-to-vehicle connectivity technologies have generated significant interest in platooning for commercial vehicles, where two or more vehicles travel in same traffic lane in relatively close proximity. This paper examines the effect of platooning on four increasingly aerodynamic tractor-trailer configurations, using a Lattice Boltzmann based CFD solver. Each platoon consisted of three identical tractor-trailer configurations traveling in the same lane at 65mph. Two different vehicle to vehicle gaps were studied, 5m and 9m, in addition to singleton (solitary) vehicles, representing an effectively infinite gap. Aerodynamic drag for the lead, middle, and trailing vehicle in the platooning configurations were compared to the corresponding single vehicle tractor-trailer configuration.

The importance of fuel economy and emission standards has increased rapidly with high fuel costs and new environmental regulations. This requires analysis techniques capable of designing the next generation long-haul truck to improve both fuel efficiency and cooling. In particular, it is important to have a predictive design tool to assess how exterior design changes impact aerodynamic performance. This study evaluates the use of a Lattice Boltzmann based numerical simulation and the National Research Council (NRC) Canada's wind tunnel to assess aerodynamic drag on a production Volvo VNL tractor-trailer combination. Comparisons are made between the wind tunnel and simulation to understand the influence of wind tunnel conditions on truck aerodynamic performance. The production VNL testing includes a full range of yaw angles to demonstrate the influence of cross wind on aerodynamic drag.

A large percentage of on-highway tractors today have air suspensions. Air suspensions require some type of control system to adjust the ride height. This system is usually referred to as a Load Leveling System. These systems come in a variety of different configurations but all basically have the same functions. When designed correctly, the system can reduce driveline vibration, reduce air consumption (improving compressor life and fuel efficiency), provide an accurate 5th wheel height and improve the ride quality. This paper explores how the characteristics of the leveling system affect the roll stability. One and Two-valve systems are considered, as well as, the position of the valve, response times, valve deadband and the systems response to an off-center load. Notably not every conceivable condition has been considered.