Patent Abstract:
A charger cooling air source selection method includes cooling a vehicle battery charger by opening an outside air vent door in a vehicle and drawing outside air through the outside air vent door; determining whether the outside air vent door will close; and if the outside air vent door will not close, establishing and maintaining positive air pressure in a cabin of the vehicle by ensuring an open configuration of a recirculation door in the vehicle.

Full Description:
FIELD 
     Illustrative embodiments of the disclosure generally relate to outside air (OSA) vent systems which facilitate flow of cool outside air into the vehicle to cool a battery charger in the vehicle. More particularly, illustrative embodiments of the disclosure relate to a charger cooling air source selection method which facilitates positive air pressure in a vehicle to prevent inflow of outside air in the event that the OSA vent system does not close. 
     BACKGROUND 
     High voltage chargers in PHEV (plug-in hybrid elective vehicles) can become sufficiently heated to warm the cabin air inside the vehicle depending on the starting interior temperature of the vehicle. Circulating inside air to cool the charger for several hours can heat up the inside vehicle air, rendering the charger inefficient. 
     When the charger requires cooling and the inside cabin air is above a set temperature level, introduction of outside air into the vehicle cabin through an outside air (OSA) vent system in the vehicle may facilitate cooling of the charger. In some circumstances, however, the OSA vent system may inadvertently remain open. Therefore, it may be desirable to facilitates positive air pressure in the vehicle to prevent inflow of outside air in the event that the OSA vent system does not close. 
     Accordingly, a charger cooling air source selection method which facilitates positive air pressure in a vehicle to prevent inflow of outside air in the event that the OSA vent system does not close may be desirable for some applications. 
     SUMMARY 
     Illustrative embodiments of the disclosure are generally directed to a charger cooling air source selection method which facilitates positive air pressure in a vehicle to prevent inflow of outside air in the event that the OSA vent system does not close. An illustrative embodiment of the method includes cooling a vehicle battery charger by opening an outside air vent door in a vehicle and drawing outside air through the outside air vent door; determining whether the outside air vent door will close; and if the outside air vent door will not close, establishing and maintaining positive air pressure in a cabin of the vehicle by ensuring an open configuration of a recirculation door in the vehicle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Illustrative embodiments of the disclosure will now be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  is a block diagram of an exemplary outside air (OSA) vent system of a vehicle in implementation of an illustrative embodiment of the charger cooling air source selection method; 
         FIG. 2  is a top view of a vehicle illustrating normal flow of outside air into the vehicle through the OSA vent system in implementation of an illustrative embodiment of the charger cooling air source selection method; 
         FIG. 3  is a side view of a vehicle illustrating normal flow of outside air into the vehicle through the OSA vent system in implementation of an illustrative embodiment of the charger cooling air source selection method; 
         FIG. 4  is a top view of a vehicle illustrating maintenance of positive air pressure in the vehicle under circumstances in which the OSA vent system inadvertently remains opened in implementation of an illustrative embodiment of the charger cooling air source selection method; 
         FIG. 5  is a side view of a vehicle illustrating maintenance of positive air pressure in the vehicle under circumstances in which the OSA vent system inadvertently remains opened in implementation of an illustrative embodiment of the charger cooling air source selection method; 
         FIG. 6  is a flow diagram which illustrates an illustrative embodiment of the charger cooling air source selection method; and 
         FIG. 7  is a flow diagram which illustrates an exemplary method of opening an OSA vent system according to an illustrative embodiment of the charger cooling air source selection method. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable users skilled in the art to practice the disclosure and are not intended to limit the scope of the claims. Moreover, the illustrative embodiments described herein are not exhaustive and embodiments or implementations other than those which are described herein and which fall within the scope of the appended claims are possible. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. 
     Referring initially to  FIGS. 1-5 , a vehicle  100  in implementation of an illustrative embodiment of the charger cooling air source selection method is shown. The vehicle  100  may have a vehicle front end  101 , a vehicle rear end  102 , a vehicle cabin  103  and a vehicle dashboard  104  in the vehicle cabin  103 . A recirculation door  108  may be included in the vehicle dashboard  104 . Responsive to operation of the vehicle climate control fan (not shown), the recirculation door  108  may facilitate selective introduction of outside air  109  ( FIG. 4 ) into the vehicle cabin  103  or recirculation of inside air  134  in the vehicle cabin  103 , such as in the conventional manner. In exemplary operation, the recirculation door  108  is closed during hot humid weather when the operator of the vehicle  100  selects the “Max A/C” setting on the vehicle climate control system, thereby recirculating cabin air to reduce the heat load on the evaporator and cool the vehicle cabin  103  more quickly. As shown in  FIGS. 3 and 4 , a battery cooling fan  130  may circulate battery cooling air  131  from inside the vehicle cabin  103  through a vehicle battery  122  ( FIG. 1 ). 
     An outside air (OSA) vent system  112  may be provided at the vehicle rear end  102  of the vehicle  100 . As shown in  FIG. 1 , the OSA vent system  112  may include an OSA vent door  113  which is selectively opened and closed by operation of a OSA vent door actuator  114 . A fan inlet duct  115  may lead from the OSA vent door  113 . An OSA fan  116  may be provided in the fan inlet duct  115 . A fan outlet duct  117  may lead from the OSA fan  116 . A battery charger  120  for a vehicle battery  122  is disposed in thermally conductive contact with the fan outlet duct  117 . As shown in  FIGS. 2-5 , an air extractor  132  may be provided at the vehicle rear end  102  of the vehicle  100  to extract inside air  134  from the vehicle cabin  103 . 
     The outside air vent system  112  may be configured to maintain the OSA vent door  113  in a closed configuration unless the battery charger  120  requires cooling and the temperature of the vehicle cabin  103  exceeds a predetermined set temperature. As shown in  FIG. 1 , upon opening of the OSA vent door  113  by the OSA vent door actuator  114 , the OSA fan  116  draws outside air  118  through the fan inlet duct  115  and the fan outlet duct  117  and into the vehicle cabin  103 . As shown in  FIGS. 2 and 3 , the inflowing outside air  118  cools the battery charger  120  to within a target temperature range which ensures optimal operation of the battery charger  120 . Upon cooling of the battery charger  120  to within the target temperature range, the OSA vent door actuator  114  may close the OSA vent door  113  and further operation of the OSA fan  116  may be terminated. Throughout operation of the outside air vent system  112 , the recirculation door  108  may remain closed to facilitate recirculation of air in the vehicle cabin  103 . The air extractor  132  may remove inside air  134  from the vehicle cabin  103 . 
     According to the charger cooling air source selection method, the vehicle controller may be configured to operate the recirculation door  108 , the vehicle climate control fan (not shown) and the outside air vent system  112  in an error mitigation strategy in the event that the OSA vent door  113  inadvertently does not close after cooling of the battery charger  120 . The error mitigation strategy maintains positive air pressure  126  in the vehicle cabin  103  and causes the recirculation door  108  to open if it is closed and prevents the recirculation door  108  from closing if it is open, and operates the vehicle climate control fan (not shown). Accordingly, as shown in  FIGS. 4 and 5 , outside air  109  flows into the vehicle  100  through the open recirculation door  108 . The inflowing outside air  109  maintains positive air pressure  126  in the vehicle cabin  103 , facilitating flow of inside air  134  from the vehicle cabin  103  through the OSA vent door  113 . The positive air pressure  126  in the vehicle cabin  103  prevents exhaust as well as hot and humid air from entering the vehicle cabin  103  from the rear area of the vehicle  100  through the OSA vent door  113 . Since the need to cool the battery charger  120  and operate the vehicle climate control in the “Max A/C” setting on the vehicle climate control system may be likely to occur under the same hot environmental conditions, the probability of the OSA vent door  113  being opened and the recirculation door  108  being closed may be high. 
     Referring next to  FIG. 6 , a flow diagram  600  which illustrates an illustrative embodiment of the charger cooling air source selection method is shown. Normal operation of a recirculation door and outside air vent system is shown in blocks  602 - 618 . Mitigating operation of the recirculation door and outside air vent system is shown in blocks  620 - 628 . In block  602 , charging of the vehicle battery by operation of the battery charger may be initiated. In block  604 , a charger fan which cools the charger may be started. In block  606 , a determination may be made as to whether the temperature of the vehicle cabin exceeds a predetermined set temperature. If yes, then the OSA vent door of the outside air vent system may be opened to cool the vehicle cabin interior. If no, then a determination may be made as to whether charging of the vehicle battery is complete. 
     Upon charging of the vehicle battery in block  610 , the OSA vent door may be closed in block  612 . In block  614 , verification may be made as to whether the OSA vent door is closed. If the OSA vent door is closed in block  614 , then the OSA vent door is powered down in block  618 . If the OSA vent door is not closed in block  614 , then an error flag is set in block  616  and the OSA vent door is powered down in block  618 . 
     In the event that the OSA vent door is not closed in block  614  and the error flag is set in block  616 , mitigating operation of the recirculation door and outside air vent system is carried out in blocks  620 - 628 . In block  620 , the vehicle is keyed on. In block  622 , the OSA error flag which was set in block  616  is checked. In block  624 , verification may be made as to whether the OSA error flag was set. If yes, then in block  626 , a command may be transmitted to the vehicle climate control system to inhibit closure and open the front recirculation door if closed. Accordingly, positive air pressure develops in the vehicle cabin such that air is not able to enter the cabin interior through the open OSA vent door. If the OSA error flag was not set in block  624 , then normal operation of the recirculation door may be carried out in block  628 . 
     Referring next to  FIG. 7 , a flow diagram  700  which illustrates an exemplary method of opening an OSA vent system according to an illustrative embodiment of the charger cooling air source selection method is shown. In block  702 , a determination may be made as to whether the battery charger is on. If the answer to the query is yes, a determination may be made as to whether the temperature of the battery charger exceeds a temperature in which the battery charger could be damaged. If no, the method may return to block  702 . If the answer to the query in block  702  is yes, the OSA vent door of the outside air vent system is opened in block  706 . In block  708 , verification may be made as to whether the OSA vent door has opened. If the OSA vent door has not opened, then in block  710 , opening of the OSA vent door may be retried. In block  712 , a determination may be made as to whether failure of the OSA vent door to open has occurred more than 3 times for the cycle. If not, then the method may return to block  706 . If so, then a door fault may be set in block  714  and the method may return to block  702 . 
     If the OSA vent door has been opened in answer to the query in block  708 , then a determination may be made as to whether charging has been completed in block  716 . If not, the query may be continued in block  716 . If yes, then the OSA vent door may be closed in block  718  and the method may return to block  702 . 
     Although the embodiments of this disclosure have been described with respect to certain exemplary embodiments, it is to be understood that the specific embodiments are for purposes of illustration and not limitation, as other variations will occur to those of skill in the art.

Technology Classification (CPC): 1