Patent Publication Number: US-8111250-B2

Title: Remote status multifunction display for a transport vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. patent application Ser. No. 11/674,522, filed Feb. 13, 2007, which claims priority to U.S. Provisional Application No. 60/774,845, filed Feb. 17, 2006, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND 
     The present invention relates to a display for a transport refrigeration system. More particularly, the present invention relates to a multifunction display that is configured to vary between a forward view mode and a mirror view mode. 
     Transport vehicles (e.g., straight trucks and tractor-trailers) are often used to transport cargo that must be maintained at predetermined conditions during transportation to preserve the quality of the cargo. The cargo is transported, stored, or otherwise supported within a conditioned space of the transport vehicle (e.g., a trailer, etc.). The cargo may be food, agricultural goods or various other temperature critical items that must be maintained at a predetermined temperature. Typically, transport vehicles that transport temperature sensitive cargo are constructed with the conditioned space maintained at a predetermined temperature by a refrigeration unit attached to the trailer. Often, the refrigeration unit is controlled by a temperature control unit mounted to the trailer adjacent the refrigeration unit. These temperature control units are configured to monitor and control the refrigeration units, and include a display that is operable to show the temperature of the conditioned space. 
     Precise control of the conditioned space is needed to maintain the cargo at the predetermined conditions, which requires constant monitoring by an operator of the transport vehicle. Most transport vehicles require the operator to stop the transport vehicle and exit the transport vehicle to view a display of the temperature control unit. However, these temperature control units are located on the transport vehicle such that it is unreadable by the operator from within a cabin of the transport vehicle. The display on the temperature control unit is also difficult to view because the display is insufficiently illuminated. 
     The transport vehicle includes a primary fuel reservoir that is operable to fuel the truck. Typically, the refrigeration unit is coupled to a secondary fuel reservoir that is separate from the primary reservoir. Some transport vehicles include a float level gauge with a display attached to an end of the secondary fuel reservoir. Other vehicles display the fuel level on the temperature control unit. However, the operator, when positioned within the vehicle, is unable to see the fuel level of the secondary reservoir. As is sometimes the case, the operator may be unaware that the fuel for the refrigeration unit is low or has run out, causing disruption of the operation of the refrigeration unit. Further, locating the fuel level gauge on the secondary reservoir or on the temperature control unit makes viewing the fuel level difficult when the transport vehicle is parked in a staging area side-by-side with other vehicles. 
     Some transport vehicles include a temperature control unit that displays the temperature in either a forward view or in a mirror view. When the transport vehicle includes the forward view, the operator may view the temperature from outside the transport vehicle, but not from the inside of the vehicle. In mirror view, the temperature control unit display is visible and readable by the operator from inside the cabin of the transport vehicle. However, these temperature control unit displays cannot be automatically switched between the forward view and the mirror view. Other displays include a manual switch to vary between the forward view and the mirror view. Typically, the manual switch is adjacent the temperature control unit and requires the operator to vary the switch from outside the vehicle. Often, manual operation of the switch is overlooked and the display is shown in an undesired view (e.g., forward view when the vehicle is traveling, etc.), and inhibits viewing of the temperature of the space. 
     SUMMARY 
     In one embodiment, the invention provides a display for a transport unit. The transport unit includes a vehicle, a trailer that defines a space, and a sensor that is in communication with the transport unit and that senses a parameter of the transport unit. The display unit includes a housing that is attachable to the trailer, and a display portion coupled to the housing. The display portion includes a screen configured to display the parameter. A controller is in electrical communication with the display portion to display the parameter on the screen. The controller is programmed to selectively switch the screen between a forward view mode and a mirror view mode such that the parameter is readable on the screen from outside the vehicle and from inside the vehicle based on a relationship between the vehicle and the trailer. 
     In another embodiment, the invention provides a transport unit that includes a trailer and a vehicle. The trailer defines a space that has at least one zone, and the vehicle is attachable to the trailer. The vehicle includes a passenger compartment and a rear view mirror. The sensor is in communication with the transport unit and senses a parameter of the transport unit. The transport unit further includes a housing coupled to the trailer, and a display that has a screen to display the parameter. A controller is attached to the trailer and in communication with the space. The controller is in electrical communication with the sensor and the display, and is programmed to selectively switch the screen between a forward view mode and a mirror view mode based on a relationship between the vehicle and the trailer. 
     In yet another embodiment, the invention provides a transport unit that includes a trailer that defines a space, and a fuel reservoir that is coupled to the trailer. The transport unit also includes a vehicle that is attachable to the trailer, and that includes a passenger compartment. A temperature control unit is attached to the trailer and operable to vary the conditions of the space. A sensor is in communication with the fuel reservoir, and senses a fuel level of the fuel reservoir. The transport unit also includes a controller coupled to the trailer and in electrical communication with the sensor to receive a signal indicative of the fuel level from the sensor. The controller includes a first display that displays the fuel level such that the fuel level is readable from outside the passenger compartment. A second display is coupled to the trailer and in electrical communication with the controller. The second display receives a signal indicative of the fuel level from the controller based on the signal received from the sensor such that the fuel level is selectively readable from inside the passenger compartment and from outside the passenger compartment. 
     In yet another embodiment, the invention provides a method of displaying a parameter of a transport unit. The method includes providing a transport unit including a trailer, and a vehicle attachable to the trailer. The method also includes providing a controller coupled to the trailer, and a display in electrical communication with the controller. The method further includes sensing the parameter with a sensor that is in communication with the transport unit, delivering a signal indicative of the parameter to the controller, and displaying the parameter on the display, and automatically adjusting the display between a forward view mode and a mirror view mode on the display based on a relationship between the vehicle and the trailer. 
     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a transport vehicle including a truck, a trailer, and a refrigeration unit having a microcontroller and a multifunction display. 
         FIG. 2  is a perspective view of the trailer of  FIG. 1 , including the microcontroller and the multifunction display. 
         FIG. 3  is a perspective view of the multifunction display of  FIG. 2 . 
         FIG. 4  is a front view of the multifunction display of  FIG. 2  in a forward view mode. 
         FIG. 5  is another front view of the multifunction display of  FIG. 2  in the forward view mode. 
         FIG. 6  is yet another front view of the multifunction display of  FIG. 2  in a mirror view mode. 
         FIG. 7  is yet another front view of the multifunction display of  FIG. 2 . 
         FIG. 8  is a flow chart diagram of the operation of one embodiment of the multifunction display of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. 
       FIG. 1  shows a transport vehicle  10  including a vehicle  15  (e.g., straight truck, tractor, etc.) and a trailer  20 . The vehicle  15  moves the trailer  20  from one location to another and includes a cabin  25 , a rear view mirror  30 , and a power cord  35  (e.g., Susie-Cord, etc.). A primary fuel reservoir (not shown) supplies fuel to an engine (not shown) of the vehicle  15 . The rear view mirror  30  allows an operator of the vehicle  15  to view objects (e.g., the trailer  15 , other vehicles, etc.) from the cabin  25 . The cord  35  electrically couples to the trailer to power electrical components on the trailer  20 . 
     The trailer  20  transports cargo (not shown) within a conditioned space  40  that must be maintained at predetermined conditions (e.g., temperature, humidity, etc.) during transportation to preserve the quality of the cargo. The cargo may be food, agricultural goods or various other temperature critical items (e.g., medical supplies, etc.) that must be maintained at the predetermined conditions. 
     The trailer  20  includes a refrigeration unit  45 , a refrigeration unit microcontroller  50 , and a multifunction display  55 . The refrigeration unit  45  maintains the cargo at a predetermined temperature and may include one or more refrigeration components (not entirely shown), such as one or more compressors, a condenser, an evaporator, one or more fans, a receiver, and one or more expansion valves. A prime mover (not shown) is coupled to the refrigeration unit  45  and is operable to drive the refrigeration unit  45 . The prime mover initiates a predetermined refrigeration cycle (i.e., a cooling cycle or a heating cycle), and to end the predetermined refrigeration cycle after the predetermined conditions of the space have been met. The starting and stopping of the prime mover is defined by the requirements of suitably conditioning the space  40 . Alternatively, the prime mover can be operated continuously to provide adequate conditioning of the space  40 . The prime mover is connected to a secondary fuel reservoir (not shown) separate from the primary reservoir. In other embodiments, the prime mover may be connected to a fuel source shared with the vehicle engine. In still other embodiments, the prime mover may be an electric motor. 
       FIG. 2  shows one embodiment of the microcontroller  50  and the multifunction display  55  that is disposed on the trailer  20  adjacent the refrigeration unit  45 . The microcontroller  50  works with a controller area network to monitor and control the temperature of the space  40 , to monitor a fuel level of the secondary reservoir, and to monitor and control a control status of the refrigeration unit  45 . The microcontroller  50  includes a monitor  60  and a temperature control  65  having a plurality of inputs  70 . The monitor  60  facilitates display of aspects of the refrigeration unit  45 , including the temperature, the fuel level, and the control status. The temperature control  65  is in communication with the refrigeration unit  45  to facilitate local control of the temperature of the space using the plurality of inputs  70 . In some constructions, the temperature of the space is determined from a return air temperature in the refrigeration unit  45 . Other constructions may determine the temperature from other locations, such as from the space  40 . One example of the microcontroller  50  includes Thermo King&#39;s SR2 controller, although other controllers may be used in place of the SR2 controller. 
     The multifunction display  55  is coupled to the trailer  20  adjacent the microcontroller  50 . The multifunction display  55  is visible from the cabin  25  through the rear view mirror  30 . A bracket  75  attaches the multifunction display  55  to the trailer  20  using common fasteners (e.g., screw, bolt, etc.). The bracket  75  is coupled to the trailer  20  using additional fasteners. 
       FIGS. 3-7  illustrate the multifunction display  55  including a housing  80 , a dimming feature or optical sensor  85 , and a screen  90  coupled to a portion of the housing  80 . The multifunction display  55  is in electrical communication with the microcontroller  50  and a power source (not shown) through an electrical connector  93  that extends from the housing  80 . The housing  80  defines a space that is operable to support a microprocessor or other similar device (not shown) to communicate with the microcontroller  50  and to vary the information that is displayed on the screen  90 . 
     The optical sensor  85  automatically adjusts the brightness of the screen  90 . In one embodiment, the optical sensor  85  automatically brightens the screen  90  during daylight operation, and automatically dims the brightness of the screen  90  during nighttime operation. The automatic brightness adjustment allows the operator to adequately view the screen  90  under various conditions. The optical sensor  85  is always active to reduce glare on the screen  90  that is visible by the operator and to prolong the life of the multifunction display  55 . 
     The screen  90  includes a real-time temperature portion  95 , a real-time fuel portion  100 , and a real-time control status portion  105 . The temperature portion  95  is in communication with the microcontroller  50  such that the temperature displayed on the screen  90  is similar to, or the same as, the temperature measured by the microcontroller  50 . The multifunction display  55  obtains the temperature based on a first predetermined interval (e.g., one second, 2 seconds, etc.). The temperature on the screen  90  may be shown in Fahrenheit scale and Celsius scale. The multifunction display  55  varies the scale depending on the connection of the multifunction display  55  with the microcontroller  50 . 
     The temperature portion  95  includes a first temperature indicator  110 , a second temperature indicator  115 , and at least one temperature zone indicator  120 . The first temperature indicator  110  includes a plurality of light emitting diodes (LEDs) to illuminate the temperature value on the screen  90 . The second temperature indicator  115  is adjacent the first temperature indicator  110  and includes at least one LED to selectively illuminate in response to whether the temperature value is positive or negative. The second temperature indicator  115  is disposed on two sides of the first temperature indicator  110  to facilitate viewing of the temperature in different modes, as discussed in detail below. The first and second temperature indicators  110 ,  115  may include any color of LEDs, such as white and amber LEDs. In other constructions, the first and second temperature indicators may include a digital indicator (not shown) in place of the LEDs. 
     The temperature portion  95  further includes a forward view mode and a mirror view mode. The multifunction display  55  switches automatically and selectively between the forward view mode and the mirror view mode in response to attachment and detachment of the vehicle  15  and the trailer  20 . The multifunction display  55  defaults to the forward view mode when the vehicle  15  is disengaged from the trailer  20 . The forward view mode allows the operator to view the screen  90  from outside the cabin  25  when the vehicle  15  is disengaged from the trailer  20 . For example,  FIGS. 4 and 5  show the screen  90  including the temperature in the forward view mode such that the operator is able to view the temperature directly from the screen  90 . The operator is thus able to view the temperature portion  95 , the fuel portion  100 , and the control status portion  105  from outside the cabin  25 . 
     The mirror view mode allows the operator to view the screen  90  from the cabin  25  using the rear view mirror  30 . The operator is thus able to continuously monitor the temperature portion  95 , the fuel portion  100 , and the control status portion  105  of the refrigeration unit. For example,  FIG. 6  illustrates the temperature of the space  40  as a negative temperature in the mirror view mode. The second temperature indicator  115  is illuminated on a side of the first temperature indicator  110  such that the screen  90  is readable by the operator by looking through the rear view mirror  30 . The automatic switching between the forward view mode and the mirror view mode allows the operator to focus on other tasks associated with the transport vehicle  10  because the temperature is shown in the appropriate view without direct operation of the multifunction display  55  by the operator. 
     One embodiment of the automatic switching between the forward view mode and the mirror view mode includes a sensor wire  125  (see  FIG. 1 ) attached to the cord  35 . The cord  35  is adapted to include the sensor wire  125  without additional terminals on the trailer  20  to receive the sensor wire  125 . The sensor wire  125  generates a signal indicative of power from a voltage source of the vehicle  15  and communicates the signal to the multifunction display  55 . The multifunction display  55  varies between the forward view mode and the mirror view mode based on the signal from the sensor wire  125  that is indicative of the voltage from the vehicle  15 . 
     Another embodiment of the automatic switching between the forward view mode and the mirror view mode includes a sensor  130  (see  FIG. 2 ) attached to or adjacent the multifunction display  55 . The sensor  130  is operable to sense the proximity of the vehicle  15  with regard to the position of the trailer  20  by emitting a signal (e.g., ultrasonic wave, etc.) in a direction away from a front of the trailer  20 . The multifunction display  55  varies between the forward view mode and the mirror view mode in response to the proximity of the vehicle  15  based on a predetermined distance programmed into the multifunction display  55 . In some embodiments, the automatic switching between the forward view mode and the mirror view mode can occur when the truck is in substantial proximity to the trailer. In other embodiments, the automatic switching between the forward view mode and the mirror view mode can occur when the truck is attached to the trailer or detached from the trailer. 
     Regardless of whether the sensor wire  125 , the sensor  130 , or other signal-generating component is used to indicate a relationship between the vehicle  15  and the trailer  20 , the multifunction display  55  automatically switches between the forward view mode and the mirror view mode based on a relationship between the vehicle  15  and the trailer  20 . In still other embodiments, the multifunction display  55  may further include an input device (not shown) to allow manual change of the multifunction display  55  between forward view mode and the mirror view mode while the tractor  15  is attached to the trailer  20  (e.g., while the tractor-trailer assembly is attached and non-moving). 
     The temperature zone indicator  120  is indicative of a zone of the conditioned space  40  that is monitored and controlled by the microcontroller  50 . The zone indicator  120  includes at least one LED disposed on the screen  90  below the first temperature indicator  110 . The zone indicator  120  may include any color of LED, such as a white LED and an amber LED. The embodiment of the screen  90  shown in  FIGS. 3-7  includes a capacity to display up to three separate temperature zone indicators  120  on the screen. Each zone indicator  120  is selectively illuminated on the multifunction display based on a time interval that is the same as the first predetermined interval. The zone indicator  120  may include fewer than three or more than three temperature zone indicators  120  to show the number of zones that are monitored. The quantity of temperature zone indicators  120  on the screen  90  is for illustrative purposes only and the invention should not be so limited. 
       FIGS. 3-6  illustrate the fuel portion  100  disposed on the screen  90  adjacent a side of the temperature portion  95 . A sensor (not shown) is in communication with the fuel reservoir to measure a fuel level of the reservoir. In some embodiments, the fuel level can be displayed on a gauge (not shown) attached to the fuel reservoir. 
     The microcontroller  50  is in electrical communication with the sensor to receive a signal indicative of a real-time fuel level of the fuel reservoir, and to display the fuel level on the display  60 . In some embodiments, the microcontroller  50  displays the sensed fuel level on the display  60  as a percentage-of-fuel value. For example, when the fuel reservoir is at about fifty-percent capacity, the microcontroller  50  displays the fuel level as fifty percent. The fuel level is disposed on the display  60  such that the operator may view the real-time fuel level from outside the cabin  25 . 
     The microcontroller  50  shares the real-time fuel level with the multifunction display  50  through the controller area network such that the multifunction display  55  and the microcontroller  50  display a similar fuel level at a given time. In other embodiments, a control box (not shown) aids in communicating the fuel level between the microcontroller  50  and the multifunction display  55  when a controller area network is unavailable. The fuel level is obtained by the multifunction display  55  from the microcontroller  50  based on a second predetermined interval (e.g., two seconds, five seconds, etc.). The second predetermined interval may be the same or different from the first predetermined interval. The fuel portion  100  is disposed on the screen  90  such that the operator may view the real-time fuel level in the forward view mode and the reverse view mode. 
     The fuel portion  100  includes gauge indicators  135  and a plurality of fuel level indicators  140 . The gauge indicators  135  are illuminated to define outer limits of the fuel portion  100 , and include at least one LED having an amber color, although other colors of the LEDs are possible.  FIGS. 3-6  illustrate the gauge indicators  135  adjacent a top and a bottom of the fuel portion  100 , although other configurations of the fuel portion  100  may place the gauge indicators  135  in other locations. 
     The plurality of fuel level indicators  140  include LEDs that display the real-time fuel level of the secondary fuel reservoir. The fuel level indicators  140  change color based on predetermined fuel levels. For example, when the fuel level is above one-quarter full, the fuel level indicators  140  are shown as white LEDs. When the fuel level is equal to or less than one-quarter full, the fuel level indicators  140  are shown as amber LEDs. Other constructions of the fuel portion  100  may include other predetermined fuel levels (e.g., one-half full, one-eighth full, etc.) that are operable to change the color of the fuel level indicators  140 . The color of the LEDs may also vary from the white and amber LEDs described herein. In still other constructions, the fuel level indicators  140  increase in scale when the fuel level drops below a predetermined fuel level. 
       FIGS. 3-7  show the control status portion  105  on the screen  90 . The multifunction display  55  receives a signal from the microcontroller  50  indicative of the control status of the refrigeration unit  45  based on a third predetermined interval. The third predetermined interval may be the same or different from the first and second predetermined intervals described above. The status portion  105  includes a status marker having a first status indicator  145  and a second status indicator  150 . The first status indicator  145  includes at least one LED having a first color, such as white, and selectively illuminates when the refrigeration unit  45  is under normal operating conditions. Normal operating conditions include, but are not limited to, the temperature of the space  40  maintained within a predefined range and an adequate fuel level to operate the refrigeration unit  45 . Under normal operating conditions, each zone indicator  120  selectively illuminates based on the first predetermined interval to indicate the zone that is currently monitored.  FIGS. 4 and 6  illustrate two examples of the control status of the refrigeration unit  45  in normal operating conditions. 
     The second status indicator  150  selectively illuminates when a check alarm condition of the refrigeration unit  45  occurs, and includes at least one LED. In some constructions, the second status indicator  150  may include a color (e.g., amber, red, etc.) that is different from the first status indicator  145 .  FIG. 5  illustrates the multifunction display  55  after a check alarm condition has been received from the microcontroller  50 . The check alarm condition includes, but is not limited to, the temperature of the space  40  outside the predetermined range or a substantially low fuel level. 
       FIG. 7  illustrates a shutdown alarm condition of the refrigeration unit  45  on the status portion  105 . When a shutdown alarm condition occurs, the microcontroller  50  sends a signal indicative of the shutdown alarm condition to the multifunction display  55 , which in turn varies from the normal operating condition and the check alarm condition to the shutdown alarm condition. The shutdown alarm condition is operable to blank the screen  90  except for the zone indicator  120 . The zone indicator  120  remains illuminated to indicate that the shutdown alarm condition has occurred in the refrigeration unit  45 . Illumination of the zone indicator  120  also indicates that the multifunction display  55  has power and is operating. In embodiments including more than one zone indicator  120 , all zone indicators are illuminated when the multifunction display  55  varies from the normal shutdown condition and the check alarm condition to the shutdown alarm condition. The microcontroller  50  generates a signal indicative of the shutdown alarm condition when the refrigeration unit  45  is inoperable, such as when the refrigeration unit  45  is not working properly or the secondary fuel reservoir is empty. 
       FIG. 8  illustrates one embodiment of operation of the multifunction display  55 . At step  155  the refrigeration unit  45 , the microcontroller  50 , and the multifunction display  55  are turned on. The status portion  105  illuminates the first status indicator  145  upon startup of the refrigeration unit  45  at step  160 . The multifunction display  55  connects to the microcontroller  50  at step  165 . At step  170 , the multifunction display  55  obtains the temperature of a first zone of the space  40  from the microcontroller  50  and displays the temperature on the temperature portion  95 . The multifunction display  55  repeatedly checks the temperature of the first zone based on the first predetermined interval. After predetermined cycle operations (e.g., four), the multifunction display  55  moves to step  175  and receives the signal indicative of the fuel level from the microcontroller  50  based on the second predetermined interval, and shows the fuel level on the fuel portion  100 . The multifunction display  55  then receives the signal indicative of the status of the refrigeration unit  45  at step  180  based on the third predetermined interval. The multifunction display  55  displays the status of the refrigeration unit  45  on the status portion  105 . 
     At step  180 , the multifunction display  55  determines the status of the refrigeration unit  45  through the microcontroller  50 . When there has been no alarm condition or shutdown condition signal generated by the microcontroller  50 , the first status indicator  145  remains illuminated on the screen  90  at step  185 . The multifunction display  55  deactivates the first status indicator  145  and illuminates the second status indicator  150  on the screen  90  at step  190  if the microcontroller  50  generates the check alarm condition. If the microcontroller  50  generates a signal indicative of the shutdown alarm condition, the multifunction display  55  will blank the screen  90  at step  195 . The zone indicator  120  remains illuminated on the otherwise blank screen  90 . 
     The multifunction display determines whether the transport vehicle  10  includes more than one temperature zone that is cooled by the refrigeration unit  45  at step  200  after determining the status of the refrigeration unit  45  at step  180  and changing the status marker according to the operating condition of the refrigeration one of the steps  185 ,  190 ,  195 . If the answer at step  200  is “No”, the process returns to step  170  and repeats as described above. If the answer at step  200  is “Yes” (i.e., the vehicle includes more than one temperature zone), then the multifunction display  55  determines whether the temperature of a second zone of the space  40  has been requested at step  203 . If the temperature of the second zone has not been requested at step  203  (i.e., the answer at step  203  is “No”), the multifunction display  55  obtains the temperature of the second zone from the microcontroller  50  at step  205 , and displays the temperature of the second zone on the temperature portion  95 . 
     The multifunction display  55  repeatedly checks the temperature of the second zone based on the first predetermined interval. After predetermined cycle operations (e.g., four), the process returns to step  175  and the multifunction display  55  obtains the signal indicative of the fuel level at step  175  and the signal indicative of the status of the refrigeration unit  45  at step  180  as described above. In a transport vehicle  10  including two temperature zones, the process shown in  FIG. 8  returns to step  170  and repeats as described above. 
     When a third temperature zone of the space  40  is available in the transport vehicle  10 , the multifunction display  55  determines at step  207  whether the temperature of the third zone has been requested. Generally, the process returns to step  170  after the multifunction display  55  has determined that the temperature of each temperature zone has been requested (e.g., the answer is “Yes” at steps  203 ,  207 ). For example, in embodiments with three temperature zones, the process returns to step  170  after the multifunction display  55  determines that the temperature of the third zone has been requested (i.e., the answer at step  207  is “Yes”). In some embodiments, if the temperature of the third zone has already been requested, the multifunction display  55  determines whether the temperature of a fourth temperature zone of the space  40 , if available, has been requested. 
     If the temperature of the third zone has not been requested at step  207  (i.e., the answer at step  207  is “No”), the multifunction display  55  obtains the temperature of the third zone from the microcontroller  50  at step  210 , and displays the temperature of the third zone on the temperature portion  95 . In some embodiments, when the third temperature zone of the space  40  is available in the transport vehicle  10 , the multifunction display can move directly from one of steps  185 ,  190 ,  195  to step  210  to obtain the temperature of the third zone from the microcontroller  50 . 
     The multifunction display  55  repeatedly checks the temperature of the third zone based on the first predetermined interval. After predetermined cycle operations (e.g., four), the process returns to step  175  and the multifunction display  55  obtains the signal indicative of the fuel level at step  175  and the signal indicative of the status of the refrigeration unit  45  at step  180  as described above. In embodiments where the transport vehicle  10  includes three temperature zones, the process of the multifunction display  55  moves from one of steps  185 ,  190 ,  195  to step  170  and repeats. In embodiments where more than three temperature zones are available, the process for the multifunction display  55  is similar to the process described above with regard the third temperature zone. 
     The multifunction display  55  automatically switches between the forward view mode and the rear view mode in response to the proximity of the vehicle  15  to the trailer  20 . Thus, the operator is capable of viewing the temperature of the space in the forward view mode from outside the cabin  25  when the vehicle  15  is detached from the trailer  20 . Likewise, when the vehicle  15  is attached to the trailer  20 , the operator is capable of viewing the temperature in the mirror view mode from inside the cabin  25  using the rear view mirror  30 . The fuel portion  100  and the status portion  105  on the screen can be viewed by the operator in the forward view mode and the mirror view mode regardless of whether the vehicle  15  is attached to the trailer  20 . 
     Various features and advantages of the invention are set forth in the following claims.