Title: HVAC Vacuum Duct Door
text: The duct door (also referred to as “valve” or “flap”) which is used to regulate the air flow in a vehicle's HVAC system (Figure 1), has undergone a significant technological evolution since the early eighties. During the past decade, this evolution has centered on the raw materials used and on the manufacturing processes in order to gain in reliability and quality as well as in weight and cost reduction. Following the review of this evolution, we will present a new development: the vacuum duct door (“VDD”). This patented concept consists in activating the rotation of the door by creating an air depression, thereby doing away with the mechanical components utilized up until now for that purpose