Improving Water-Tightness of Passenger Vehicles

Previous research has shown that water ingress into vehicles can be detrimental to driver comfort in terms of high humidity, dampness and odor and also in terms of safety, due to high misting of the windows reducing overall visibility. In extreme cases, water ingress can lead to rusting from the inside and potential biohazards as the car furnishings provide the ideal warm and damp environment for bacteria and spores to flourish. A significant route for water ingress into passenger cars is through the Heating, Ventilation, and Air-Conditioning (HVAC) system. The penetration of rainwater through the HVAC unit and the subsequent rise in moisture levels within the passenger compartment directly affect the provision of thermal comfort to the cabin occupants. Using a full-scale Climatic Wind Tunnel (CWT) facility, which incorporates accurate rain distribution modelling, it has been possible to study the movement of rainwater film over the exterior surface of the vehicle to ascertain the flow distribution of the film moving into the engine bay, into the cowl, advancing up and over the windscreen and shed to the sides and front of the vehicle. The outcome of the work benefits automotive manufacturers whose market includes tropical areas.