Patent Application
20110068601
The present invention relates generally to a solar load reduction device and more particularly to louvers mounted inside a vehicle backlight.
A significant emphasis is being placed on improving the fuel economy of automotive vehicles while maintaining or improving passenger comfort. One area in particular where fuel economy and passenger comfort can be adversely affected is with the solar load on the interior of a vehicle due to sun light shining through the vehicle windows. This solar load increases the load on the air conditioning system when cooling the vehicle interior. One window in particular, the vehicle backlight, can contribute significantly to the solar load on a vehicle parked in the sun.
Some have attempted to reduce this solar load through the use of thin, horizontally extending louvers fixed adjacent to the inside or outside of the backlight. Being fixed horizontally, the thin louvers still allow a vehicle operator to see out of the back window, while the horizontal width of each louver will reflect some of the solar load, thus reducing the heat load on the vehicle interior. However, for externally mounted louvers, the aerodynamics of the vehicle may be adversely affected. Moreover, for both interior and exterior mounted louvers, the solar load is only partially reduced, especially when the sun is not directly overhead.
An embodiment contemplates a vehicle having a vehicle structure defining a vehicle interior comprising a backlight supported by the vehicle structure and having an interior surface facing into the vehicle interior, and a solar load reduction system. The solar load reduction system may include a louver support supported by the vehicle structure, a plurality of pivotable louvers located in the vehicle interior adjacent to the interior surface, with each of the louvers pivotally mounted to the louver support and spaced from the other louvers, and a tilting mechanism adjacent to the backlight and operatively engaging the plurality of louvers to selectively cause the louvers to pivot relative to the louver support, whereby the louvers can be rotated between an open position allowing for a horizontal view through the louvers and the backlight and a closed position where the horizontal view through the louvers is blocked.
An embodiment contemplates a vehicle, having a vehicle structure defining a vehicle interior, comprising a backlight supported by the vehicle structure and having an interior surface facing into the vehicle interior, and a solar load reduction system. The solar load reduction system may include a louver support supported by the vehicle structure, a plurality of louvers located in the vehicle interior adjacent to the interior surface, with each of the louvers mounted to the louver support and spaced from the other louvers and oriented to allow for a horizontal view through the louvers, and an interior pane of translucent material supported by the vehicle structure in the vehicle interior, spaced from the backlight and adjacent to the plurality of louvers to thereby form a cavity within which the plurality of louvers are located.
An advantage of an embodiment is that the solar load transmitted through the backlight into the vehicle is reduced, which lowers the energy required to cool the vehicle interior to an acceptable temperature for occupants and other vehicle components that may require temperature management (such as a battery pack for a hybrid or electric vehicle). This reduced solar load is accomplished with minimal power consumed, minimal increase in vehicle mass and without increasing the aerodynamic drag of the vehicle.
Each of the louvers 28 is long and slender, extending horizontally from side-to-side, generally following the curvature of the interior surface 30 of the backlight 24. A pair of louver supports 38 mount at their lower ends to structure such as the rear panel 36 and at their upper ends to structure such as the roof 34. The louver supports 38 mount to each louver 28 at pivot joints 40 that support the louvers 28 in spaced relation to each other and allow for pivoting of the louvers 28 relative to the louver supports 38. The thickness of each louver 28 is preferably small, just enough to maintain the desired stiffness of each louver, in order to minimize the loss in visual field (in a horizontal direction) through the backlight 24 when the louvers 28 are in the open position (see
The solar load reduction system 22 also includes a tilting mechanism 42 that may include, for example, a tilting arm 44 that connects to each of the louvers 28 at locations spaced from the pivot joints, and a motor assembly 46 that is connected to and drives the tilting arm 44. As the motor assembly 46 is driven in one direction, the tilting arm 44 will cause each of the louvers 28 to pivot toward a closed position where the louvers lay on top of each other to fully reflect the solar load coming in through the backlight 24. As the motor assembly 46 is driven in the other direction, the tilting arm 44 will cause each of the louvers 28 to pivot to a generally horizontal position (the open position) where the blockage of the driver's view horizontally through the backlight 24 is minimized while still allowing for reflection of some of the solar load when the sun is more overhead in the sky (i.e., block sun light directed in a more vertical direction). Other types of tilting mechanisms may be employed instead, if so desired. Thus, when referring to a “motor assembly” herein, this includes other types of actuators that can be used to tilt the louvers back and forth.
The solar load reduction system 22 may also include a controller 50 that controls the operation of the motor assembly 46, and either or both of a solar load sensor 52 and a louver switch 54, which may be mounted on an instrument panel 56. The controller may be a stand alone device or may be part of a larger controller, such as a body control module or powertrain control module. The solar load sensor 52 may be mounted, for example, on the instrument panel 56 or the rear panel 36 in the vehicle interior 26. If equipped with a solar load sensor 52, the controller 50 may detect when the vehicle has been shut off for a predetermined time, for example, and if the solar load indicated by the solar load sensor 52 is above a predetermined threshold, activate the motor assembly 46 to tilt the louvers 28 to the closed position, thus minimizing the solar load entering the vehicle interior 26 through the backlight 24.
In addition, the louver switch 54 may be actuated by a vehicle occupant to activate the motor assembly 46 to tilt the louvers 28 to the closed position even if the solar load sensor 52 does not detect a high level of solar load. In this case, the switch 54 may be a three position switch, with one position that allows the controller 50, with input from the solar load sensor 52 (among other sensors), to determine the appropriate position for the louvers 28, a second position to override the solar load sensor 52 to cause the louvers 28 to open and stay opened and a third position to cause the louvers 28 to close and stay closed. Alternatively, if the louver switch 54 is connected to the motor assembly 46 via the controller 50, then the controller 50 may be optionally programmed to prevent louver closure while the vehicle 20 is running, even if the louver switch 54 is actuated to the louver closed position.
Alternatively, there may be no solar load sensor in the vehicle 20, and the louver switch 54 may be connected directly to the motor assembly 46 and pivot the louvers 28 to the opened or closed position based solely on the position the vehicle occupant places the louver switch 54. In this case, the louver switch 54 may be a two position switch. In another alternative, there may be no louver switch 54 and the position of the louvers 28 is then determined by the controller 50 based on the solar load sensor 52 and the state of other vehicle parameters.
While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.
