Abstract:
A system and method of ensuring multiple devices, which are connected in series with a controller, can be detected by and particularly identified by the controller.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of the earlier filing date of U.S. Provisional Application No. 60/424,291, filed 5 Nov. 2002, which is incorporated by reference herein in its entirety. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    A system according to the present invention is capable of ensuring that multiple devices, which are to be connected in series with a controller, are connected sequentially so as to enable the controller to particularly identify each device. In particular, a system according to the present invention incorporates a feature that ensures that even identical devices, which are to be connected in series, in a sequential order, are connected with the device closest to the controller connected first.  
         BACKGROUND OF THE INVENTION  
         [0003]    In conventional heating, ventilating, and air conditioning (HVAC) systems, such as those fitted to a vehicle, it is difficult to ensure that, during the assembly process or in servicing the system, multiple actuators are connected to the wiring harness in the correct sequential order. Conventionally, following a predefined assembly sequence is important because this enables a controller for the HVAC system to identify which actuator is located at which physical location, and hence which function a particular actuator controls.  
           [0004]    A first type of conventional HVAC system utilizes an actuator design feature, which can be either hardware or software, and which enables the controller to identify a particular actuator. Thus, each actuator in the system must have a unique feature to distinguish it from the other actuators. The first type of conventional HVAC systems suffers from a number of disadvantages including that multiple versions of essentially the same actuator are required. This results in different part numbers and additional logistical burdens both in assembly at a plant and during subsequent servicing, which result in higher costs.  
           [0005]    A second type of conventional HVAC system utilizes a hardware feature in the mating couplings to identify a particular actuator location in the wiring harness. The second type of conventional HVAC systems suffers from a number of disadvantages including that multiple coupling variants are required, which results in higher system costs, and there is a need to have a foolproof method to ensure that the correct coupling variant is assembled in the correct location along the wiring harness. Examples of additional disadvantages include that hardware coding also requires four additional wires in the harness, which further increases system cost, and that the mechanical contacts are prone to oxidation that requires bursts of current to be supplied periodically to prevent contact issues.  
         SUMMARY OF THE INVENTION  
         [0006]    The present invention provides a control system that includes a controller, a wiring harness, and a plurality of devices. The wiring harness includes a first plurality of electrical couplings that are connected in series with the controller. A first one of the first plurality of electrical couplings is located along the harness closest to the controller, and a last one of the first plurality of electrical couplings is located along the harness furthest from the controller. Each of the plurality of devices is electrically connected via the wiring harness to the controller, and electrically connected to a respective one of the first plurality of electrical couplings via a corresponding one of a second plurality of electrical couplings. And sequential electrical connection of the corresponding one of the second plurality of electrical couplings with the first through the last ones of the first plurality of electrical couplings increases a closed path of devices that are detected and identified by the controller.  
           [0007]    The present invention also provides a climate control system for a vehicle. The system includes a controller, a wiring harness, and a plurality of devices. The controller directs airflow to at least one of a footwell, interior vents, and a windshield defroster. The wiring harness includes a first plurality of electrical couplings connected in series with the controller. A first one of the first plurality of electrical couplings is located along the harness closest to the controller, and a last one of the first plurality of electrical couplings is located along the harness furthest from the controller. Each of the plurality of devices is electrically connected via the wiring harness to the controller, and electrically connected to a respective one of the first plurality of electrical couplings via a corresponding one of a second plurality of electrical couplings. And sequential electrical connection of the corresponding one of the second plurality of electrical couplings with the first through the last ones of the first plurality of electrical couplings increases a closed path of devices that are detected and identified by the controller.  
           [0008]    The present invention also provides a method of assembling a system including a controller, a wiring harness having at least two electrically open ports connected in series with the controller, and at least two devices. The method includes identifying with the controller a first one of the devices when an electrical connection via a first one of the ports creates a closed path, and identifying with the controller a second one of the devices when an electrical connection via a second one of the ports expands the closed path.  
           [0009]    The present invention further provides a method of assembling a system including a controller, a wiring harness having a plurality of electrically open ports connected in series with the controller, and a plurality of devices. The method includes defining a closed path including only the controller and a first one of the plurality of devices, and expanding the closed path so as to include only the controller, the first one of the plurality of devices, and a second one of the plurality of devices.  
         BRIEF DESCRIPTION OF THE DRAWINGS  
         [0010]    The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain features of the invention.  
           [0011]    [0011]FIG. 1 is a schematic illustration of a control system in accordance with the detailed description of a preferred embodiment, in which no devices are attached.  
           [0012]    [0012]FIG. 2 is a schematic illustration of the control system shown in FIG. 1, in which a first device is attached, detected, and particularly identified.  
           [0013]    [0013]FIG. 3 is a schematic illustration of the control system shown in FIG. 1, in which first and second devices are attached, detected, and particularly identified.  
           [0014]    [0014]FIG. 4 is a schematic illustration of the control system shown in FIG. 1, in which a second device is attached, but is not detected or particularly identified.  
           [0015]    [0015]FIG. 5 is a schematic illustration of a vehicle heating, ventilation, and air conditioning system. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]    Referring initially to FIG. 1, a wiring harness  30  electrically connects a controller  20  so as to identify the presence of an actuator  52 , 54 , 56 . The wiring harness  30  can include a power line or bus line if the actuator  52 , 54 , 56  is to communicate on a bus with the controller  20 . Preferably, the wiring harness  30  defines a line that runs through the harness and loops through a set of first connectors  42 , 44 , 46 . If one of the devices  52 , 54 , 56  is disconnected, the end of the loop is effectively removed causing an open port in the line at the respective one(s) of the set of first connectors  42 , 44 , 46 .  
         [0017]    It is a goal to ensure that the devices  52 , 54 , 56  are connected to the system in sequential order, starting with the device  52  that is nearest the controller  20  along the wiring harness  30 . As shown in FIG. 1, the controller  20  is attached to the wiring harness  30 , but no devices  52 , 54 , 56  are attached to the otherwise open ports at the set of first connectors  42 , 44 , 46 .  
         [0018]    According to a preferred embodiment, each of the set of first connectors  42 , 44 , 46  includes at least three contacts, which are matingly engageable with corresponding contacts on a set of second connectors  62 , 64 , 66 , which are respectively associated with the devices  52 , 54 , 56 .  
         [0019]    Referring now to FIGS. 2 and 3, any devices  52 , 54 , 56  on the far side of an open port with respect to the controller  20  will not be detected by the controller  20 . Therefore, if devices  52 , 54 , 56  are connected sequentially and between each connection, feedback from the controller  20  is used to determine whether the controller  20  detected each new device  52 , 54 , 56 , and the devices  52 , 54 , 56  can only be connected in one order. The device  52  nearest to the controller, measured along the wiring harness  30 , must be connected before any other devices  54 , 56  to ensure a connection to the controller  20 , and hence positive detection by the controller  20 .  
         [0020]    As shown in FIG. 2, the device  52  is connected correctly. That is to say, it is the first connected device and it is connected to wiring harness  30  at the connector  42 , which is closest to the controller  20  along the wiring harness  30 , and thereby creates a closed path that includes exclusively the controller  20  and the device  52 .  
         [0021]    As shown in FIG. 3, device  54  is subsequently connected correctly. That is to say, the device  54  is the second connected device and it is connected to wiring harness  30  at the connector  44 , which is the second closest to the controller  20  along the wiring harness  30 , and thereby creates a closed path that includes exclusively the controller  20 , the device  52 , and device  54 . Thus, the correct procedure is: (Step  1 ) connect device  52  to connector  42  on the wiring harness  30 , thereby creating a closed path including only controller  20  and device  52 ; and (Step  2 ) connect device  54  to connector  44  on the wiring harness  30 , thereby expanding the closed path to include controller  20 , device  52  and device  54 . The controller  30  detects and identifies device  52  in Step  1 , and then detects and identifies device  54  in Step  2 .  
         [0022]    Referring now to FIG. 4, if a device  54  is connected out of sequence, the controller  20  will not be able to detect the device  54  because of the open port at the first connector  42  between the device  54  and the controller  20 . Thus, an example of an incorrect assembly procedure that would be: initially connecting device  54  via first connector  44  to the wiring harness  30 , i.e., before connecting first connecting device  52  via first connector  42 . Because first connector  42  is open, the controller  20  unable to provide feedback that the connection of device  54  has been recognized, and an installer would not be able to confuse the connection of device  54  with the connection of device  52 .  
         [0023]    [0023]FIG. 5 shows a preferred embodiment according to the present invention of a heating, ventilating, and air conditioning (HVAC) system such as may be fitted to a vehicle. Airflow into the vehicle can be accelerated by a blower, e.g., a fan, and can be treated, e.g., by an air conditioner or a heater. The treated airflow can then be directed to one or more of a footwell, vent(s) or a window defroster. The controller  30  can select which one(s) of the blower, air conditioner and heater are used to treat the airflow, and drives devices  52 , 54 , 56 , e.g., actuators, that regulate the distribution of the airflow to various portions of the passenger compartment, e.g., footwell, vent(s), or window defroster.  
         [0024]    Advantages of the invention include utilizing identical devices  52 , 54 , 56  and identical connectors  42 , 44 , 46  in the wiring harness  30  so as to reduce the number of different parts required in the system. This is made possible, according to the invention, by ensuring that the devices  52 , 54 , 56  can only be connected in one sequence. The sequence of connection of the devices  52 , 54 , 56  to the system is also used by the controller  20  as the means of identifying each of the devices  52 , 54 , 56 .  
         [0025]    Using a diagnostic interface at the controller  20  after connection of each devices  52 , 54 , 56 , the user can obtain feedback from the system that each of the devices  52 , 54 , 56  has been successfully detected and identified as being at a particular position along the wiring harness, and is therefore ready to perform a specific function. If one of the devices  52 , 54 , 56  is connected to a location out of sequence, the controller  20  will not be able to detect and identify the device  52 , 54 , 56 , and no positive feedback will be provided by the controller  20 . Thus, according to the present invention, it becomes impossible to connect the devices  52 , 54 , 56  in an incorrect sequence when using feedback from the controller  20 .  
         [0026]    While the present invention has been disclosed with reference to certain preferred embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present invention, as defined in the appended claims. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims, and equivalents thereof.