Patent ID: 8939823
Filing Date: 2015-01-27
Classification: B60H

Abstract:
1. A blower unit for a vehicle HVAC system which is operable in one of a fresh air mode, a recirculation air mode and a mixture mode, the blower unit comprising: a housing defining an exterior fresh air intake aperture, an interior recirculation air intake aperture and a suction passage in communication with both the exterior and interior air intake apertures; a first door operably associated with the exterior air intake aperture for selectively opening and closing the exterior air intake aperture; a second door operably associated with the interior air intake aperture for selectively opening and closing the interior air intake aperture, the first and second doors being movable independent of each other; a partition located in the suction passage for at least partially dividing the suction passage into a first suction passage and a second suction passage, the partition having a proximal end portion and a distal end portion, the proximal end portion of the partition being selectively engaged by the first and second doors in their respective fully open position depending on the mode of the HVAC system; wherein in the mixture mode, the first door is configured to control ram pressure as vehicle speed increases to maintain a predetermined airflow ratio between fresh air flowing into the housing via the exterior air intake aperture and recirculation air flowing into the housing via the interior air intake aperture; wherein in the fresh air mode, the first door rotates to an open position to allow airflow into the blower unit through the exterior air intake aperture and the second door obstructs the interior air intake aperture, the first door selectively moving between a partial open position and the fully open position and a closed position where the first and second suction passages are blocked to control ram pressure; and wherein in the recirculation air mode, the first door rotates to the closed position to obstruct the exterior air intake aperture and the second door is moved to an open position, and when the second door is in the fully open position recirculation air flows through the first and second passages.