Abstract:
A multi-function, programmable switch display unit is used to control vehicle operation parameters in a heavy duty over-the-road truck. Several switch screens, each showing a set of related truck parameters can be selectively displayed on a display screen. A matrix of pressure sensitive switches overlays the display screen with cut-outs through which items on the display screen can be viewed. A display controller receives input from the pressure sensitive switches and maps them to the correct truck function and causes appropriate control actions to be taken.

Description:
TECHNICAL FIELD  
         [0001]    The invention concerns generally switches for over-the-highway trucks and in particular a programmable multi-function switch panel for controlling cab and chassis related functions in an over-the-highway truck.  
         BACKGROUND OF THE INVENTION  
         [0002]    As the number of vehicle control and information systems available in over-the-highway trucks increases, the space available to house the mechanical components connected with those control functions dwindles, making placement and packaging of those items more challenging. In many over-the-highway trucks, the operator accessible areas are overwhelmed with switches and displays, making it inconvenient for the operator to monitor and control various features of the truck.  
           [0003]    In addition to the great number of switches and displays that must be available to control the increasing number of vehicle control and information systems, the switches and displays in the cab often require dedicated conductors that route control and system monitoring signals to and from the switches and displays. Pass-through panels between the cab and the engine compartment are becoming crowded and access to the various conductors for repair is difficult. Within the cab, wiring in the dashboard area is also becoming complex and crowded.  
         SUMMARY OF THE INVENTION  
         [0004]    By providing numerous control screens on a single display for control by the same bank of switches, operator compartment space and control lines can be used more efficiently.  
           [0005]    A switching method and apparatus is provided for a vehicle, such as a heavy duty over-the-highway truck, having an operator compartment and at least one control module for controlling vehicle components based on input vehicle function parameters. A display module is located in the operator compartment that includes a display screen for displaying information received from a display controller. The display screen is associated with an array of pressure sensitive switches that are mapped to portions of the display screen. Memory is provided for storing a set of switch screens that convey information about related vehicle function parameters. The display controller provides signals to the display module for selectively displaying one of the set of switch screens, receives signals from the pressure sensitive switches, joins the signals from the pressure sensitive switches to a corresponding mapped vehicle function parameter based on the switch screen currently being displayed, and provides vehicle component control signals to the control module based on the received signals from the pressure sensitive switches. In one embodiment, the array of pressure sensitive switches is a mask that includes a plurality of cut outs through which information on the display screen can be viewed. In one embodiment, each switch screen is stored in a corresponding program module that stores computer executable instructions for receiving input from the pressure sensitive switches and providing appropriate control to vehicle components based on the input.  
           [0006]    Devices such as smart cards, memory sticks, EEPROM writers, or wireless computing systems may be used to program the modules. The system may include a security screen that prompts the driver to supply a password to enable the ignition system. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a schematic of a multi-function switch system for an over-the-highway truck constructed according to an embodiment of the present invention;  
         [0008]    [0008]FIG. 2 is a perspective exploded view of a portion of the multi-function switch shown in FIG. 1; and  
         [0009]    [0009]FIGS. 3, 4 and  5  are front views of the multi-function switch shown in FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0010]    For the purposes of this description, the multi-function switch system will be described in conjunction with an over-the-highway truck, however the switch system may be used in any vehicle having a variety of user controlled parameters. FIG. 1 is a schematic of an overall programmable multi-function switch system for use in an over-the-highway truck. A cab mounted display unit  25  includes a programmable multi-function switch panel  27  for displaying the status of and controlling vehicle functions. The display  25  can be an integral part of the truck instrument panel or can be a separate pod that protrudes from the instrument panel. As will described in greater detail later, a liquid crystal display  135  that displays various sets of vehicle information  28   a - 28   d  is overlaid with a matrix of pressure sensitive switches  125  to form the programmable multi-function switch panel. In addition, a set of pressure sensitive switches  23  having fixed operation modes are located below the liquid crystal display portion of the display  25 .  
         [0011]    A cab control module  35  is also located within the cab to control cab related vehicle functions. The cab module  35  provides signals to the display unit indicative of cab function status as well as control lines via cab control signal wires  32  that tie into a main signal wiring bundle  29 . A plurality of dedicated cab signal wires  37  lead from the cab control module to various cab related devices. A single high voltage lead  31  for powering the cab control module  35  protrudes through a pass through panel  49  that separates the cab from the engine compartment. A chassis control module  45  that controls non-cab related functions such as engine, transmission, and suspension components is located in the engine compartment. Like the cab control module, it provides control and status signals to the display module  25  via a bundle of chassis signal wires  42  that runs through the pass through panel and into the main signal wiring bundle  29 . A set of chassis control wires  47  connect the chassis control module  45  with various truck devices.  
         [0012]    [0012]FIG. 2 is an exploded view of the liquid crystal display  135  and an overlying mask  126 . The liquid crystal display  135  is adapted to display programmable screens  28   a - 28   d  (FIG. 1) that correspond to a user selected function group switch  23 . The mask  126  is physically registered to the liquid crystal display so that text and/or characters displayed on the liquid crystal display are visible within windows  131   a - 131   l ,  133   a - 133   l , and  135  cut into the mask. Pressure sensitive switches  125   a - 125   l  communicate with a controller (not shown) within the programmable multi-function switch panel  27  to control the displayed vehicle functions.  
         [0013]    The controller includes a number of programmable control modules or ‘chips’, each associated with a function group switch (FIG. 1). When a function switch is selected, a multiplexer places the corresponding module into communication with the switch panel  27  to display the relevant information and options. When one of control switches is activated to change a setting, the module registers the selection, initiates the appropriate action through a signal to the appropriate control device (such as a relay) and retains the setting in memory until it is changed. When another function group switch is actuated, the current control module stores the current settings prior to the muliplexer connecting the selected function group module to the display. The muliplexer insures that only one function group module is active at any given time.  
         [0014]    [0014]FIGS. 3 and 4 illustrate two versions of the programmable multi-function switch panel  27 . In FIG. 3, the “Vehicle Lighting” fixed mode switch  23  has been activated. The liquid crystal display  135  displays a pre-programmed screen that includes labels to show through windows  133   a - 133   l  and status information to show through windows  131   a - 131   l  for the various control switches  125   a - 125   l . The liquid crystal display may also display a text or graphic message for viewing through the large central window  135 . FIG. 4 shows a version of the programmable multi-function switch panel  27  when the “Driver Information” fixed mode switch has been activated. FIG. 5 illustrates the multi-function switch panel in “Security” mode. In this mode, the switch panel prompts the user for a security code, verifies the input code, and enables critical vehicle components such as the engine upon code verification. In a preferred embodiment, the driver would insert a smart card into a smart card reader (not shown) to enable the ignition system when the display panel is in security mode. The smart card would have driver security information such as access codes stored on it.  
         [0015]    Prior to installation in a truck, the programmable multi-function switch panel is programmed to display information corresponding to each fixed mode switch  23 . The number of functions that can be controlled by using the programmable multi-function switch panel as well as the nature of control is determined when the panel is programmed. Portable memory devices such as memory sticks or smart cards could be used to program the switch panel in the field. Later, the programmable multi-function switch panel can be reprogrammed to reflect updates or other enhancements without requiring the removal of the switch from the vehicle.  
         [0016]    Use of the programmable multi-function switch panel reduces the number of wires that must travel through the pass through panel, because only a single high voltage wire is required for the cab control module. The number of pneumatic lines that must travel through the pass through panel is also reduced because some chassis components have control devices that are mounted near them. When separate switches are used to control the various cab functions, numerous high voltage wires are required. In addition, since numerous vehicle functions are monitored and controlled using a single switch panel, valuable instrument panel space is conserved.  
         [0017]    In this description the invention has been described with reference to an over-the-highway truck. However, the invention is also applicable to other types of vehicles, in particular heavy duty vehicles that have a variety of driver controlled functions. Such heavy duty vehicles include not only over-the-highway trucks, but off-road vehicles such as construction machines, wheel loaders, articulated haulers, excavators.  
         [0018]    The preferred embodiments of the invention have been illustrated and described in detail. However, the present invention is not to be considered limited to the precise construction disclosed. Various adaptations, modifications and uses of the invention may occur to those skilled in the art to which the invention relates and the intention is to cover hereby all such adaptations, modifications, and uses which fall within the spirit or scope of the appended claims.