Drag reduction in a class 8 truck - scaled down model

Trucks are heavy load vehicles used mainly for commercial transport operations. There are several classes of heavy duty commercial vehicles classified based on the weight loaded. More than 50% of the engine output power in such trucks is utilized to overcome the drag. Drag force in automobiles is the resistance offered by air on vehicles at higher speeds. Class 8 trucks suffer higher drag when compared to other classes. In the present work, a numerical model is developed using a commercial code ANSYS FLUENT to predict the drag coefficient value. The effects of gap width and cab front radius with a constant fairing is analysed using the numerical model developed. A Class 8 model truck with minimal drag coefficient having constant fairing and optimized gap width between the trailer and cab is proposed.

Prospects for Implementation of Thermoelectric Generators as Waste Heat Recovery Systems in Class 8 Truck Applications

With the rising cost of fuel and increasing demand for clean energy, solid-state thermoelectric (TE) devices are an attractive option for reducing fuel consumption and CO2 emissions. Although they are reliable energy converters, there are several barriers that have limited their implementation into wide market acceptance for automotive applications. These barriers include: the unsuitability of conventional thermoelectric materials for the automotive waste heat recovery temperature range; the rarity and toxicity of some otherwise suitable materials; and the limited ability to mass-manufacture thermoelectric devices from certain materials. One class of material that has demonstrated significant promise in the waste heat recovery temperature range is skutterudites. These materials have little toxicity, are relatively abundant, and have been investigated by NASA-JPL for the past twenty years as possible thermoelectric materials for space applications. In a recent collaboration between Michigan State University (MSU) and NASA-JPL, the first skutterudite-based 100 W thermoelectric generator (TEG) was constructed. In this paper, we will describe the efforts that have been directed towards: (a) enhancing the technology-readiness level of skutterudites to facilitate mass manufacturing similar to that of Bi2Te3, (b) optimizing skutterudites to improve thermal-to-electric conversion efficiencies for class 8 truck applications, and (c) describing how temperature cycling, oxidation, sublimation, and other barriers to wide market acceptance must be managed. To obtain the maximum performance from these devices, effective heat transfer systems need to be developed for integration of thermoelectric modules into practical generators.