Re: VW Passat 2002 - Poor brake pedal # Archived Message
Posted by Andrew Ruellan on December 5, 2009, 4:41 pm, in reply to "Re: VW Passat 2002 - Poor brake pedal #"
I would love to have an explanation from the relevant design engineers as to why they did it that way! Hello Paul, I take it that you are talking about the one way grommet with "duck bill" end on it.I am not a design engineer but here is my theory.They are designed this way to stop noise entering the compartment, whistling or droning noises caused by air flow across the opening,the venturi effect drawing water upwards and water entering when under the water line (deep puddle). These are dependant on where they are fitted. The design of this is Patented under USPTO Patent Application 20080185061. I have come across some strange noises that have been caused by these things.Some were missing, others needed to be modified. One that sticks in my mind was a whistling noise from a BMW sunroof. It was whistling from the r/h front corner of the sunroof (sounded like wind noise) After many hours of testing (and a roll of masking tape) we found the end of the drain tube was picking up the air flow and causing the noise ! Others were road noise in the cabin etc. Here is an extract from the Patent description:- Duckbill seal defines a cross-shape slot which allows for the drainage of water from drain tube but which also prevents road noise and other external noises from being transmitted from outside the vehicle back to the passenger compartment. Duckbill seal also acts as a water seal to limit the amount of water that can enter drain tube through duckbill seal. Because duckbill seal is formed within enlarged annular portion of cylindrical inlet portion, the height above annular disc portion that duckbill seal extends is significantly reduced when compared to duckbill outlet of drain grommet. The lower profile of duckbill seal provides for additional clearances with other components of vehicle Patent website Regards
Andrew Ruellan
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