Design and Analysis of an Optimized Defroster Plenum

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Guo, Jinyao
Heinrichs, David M
Thacher, Eric W
Wang, Meng
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Our team was tasked with redesigning and optimizing the front windshield defroster plenum for the Xcelsior coach, manufactured by New Flyer Industries. As part of New Flyer’s continuous improvement group, the goal was to reduce waste associated with manufacturing the defroster plenum, as well as improve its performance. The defroster plenum is an air chamber that redirects hot air from the blower fan to the windshield, which melts frost and evaporates fog. Our redesigned defroster plenum has a total cost of ___ per part, with a payback on machinery after ___ coaches. With an improved low end outlet velocity of 15.4%, a decreased velocity range of 4.5 m/s, and improved thermal conductivity, our plenum will decrease the time required for defrost to less than 30 minutes. Improving the uniformity of the velocity profile will also lead to a decrease in peak noise levels. By having our design in one piece, containing pre-drilled holes and using pushpin rivets as fasteners, we will reduce the installation time by 10 to 15 minutes. Our defroster plenum can be installed by one technician at one location on the process line. The new design will be manufactured from ABS plastic, which leads to a final mass of 2.6kg.Ournew design will outperform on the following target specifications: cost, payback on machinery, installation time, defrost time, number of parts, noise, and weight. We will maintain the same number of technicians required for installation and number of locations on the assembly line where the plenum can be installed. We recommend that our final design should be moved forward for prototyping and testing at New Flyer industries. We are confident that our redesign of the defroster plenum will solve all the key problems associated with the current model.