Patent Document

BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to commercial motor vehicles and more particularly to an automated system for cycling vehicle lamps on and off to allow direct sight inspection by one person both of operability of the lamp bulbs and of the systems activating the lamps.  
           [0003]    2. Description of the Problem  
           [0004]    Commercial trucking regulations provide for periodic inspection of various commercial vehicle systems. Among vehicle systems requiring inspection are exterior lamps, such as headlights, turn indicator lamps and identification lights. An inspection must determine not only if the lamp is operable, but that systems for actuating lamps for indicating turns, braking, or for flashing, are also functioning correctly. Performing such checks has generally been much easier if two people are available to make the check, one to remain in the cab of the vehicle to depress the brakes, activate turn signals and perform other similar operations while another person walks around the vehicle to view the lamps&#39; operation.  
           [0005]    Contemporary designs for the control and management of vehicle components increasingly rely on methods derived from computer networking. Digital data are exchanged between component controllers over a common physical layer such as a shielded twisted pair of wires. Intelligible communication between two or more device controllers among a greater plurality of devices, all occurring over the common physical layer, depends upon the communicating devices being able to discriminate among messages they receive and to respond to those messages directed to them. Such methods are well known in the art and are part of the standards which the Society of Automotive Engineers (SAE) has published and continues to publish as part of the SAE J1939 protocol.  
           [0006]    The J1939 protocol provides an open protocol and a definition of the performance requirements of the medium of the physical layer, but also allows for development of proprietary protocols. The SAE J1939 protocol is a specialized application of a controller area network (CAN) and may be readily implemented utilizing commercial integrated circuits such as the C167 device from Siemens of Germany.  
           [0007]    The CAN protocol is an ISO standard (ISO 11898) for serial data communication, particularly aimed at vehicular applications. The CAN standard includes a physical layer (including the data bus) and a data-link layer, which define useful message types, arbitration rules for bus access and methods for fault detection and fault confinement. The physical layer uses differential transmission on a twisted pair wire bus. A non-destructive bitwise arbitration is used to control access to the bus. Messages are small, at most eight bytes, and are protected by checksum error detection. Each message carries a numeric value which controls its priority on the bus, and may also serve as an identification of the contents of the message. CAN offers an error handling scheme that results in retransmitted messages when they are not properly received. CAN also provides means for removing faulty nodes from the bus. CAN further adds the capability of supporting what are termed “higher layer protocols” for standardizing startup procedures including bit rate setting, distributing addresses among participating nodes or kinds of messages, determining the layout of the messages and routines for error handling on the system level.  
           [0008]    Digital data communications over serial data paths are an effective technique for reducing the number of dedicated communication paths between the numerous switches, sensors, devices and gauges installed on the vehicles. Multiplexing the signals to and from local controllers and switches promises greater physical simplicity through displacing much of the vehicle wiring harness, reducing manufacturing costs, facilitating vehicle electrical load management, and enhancing system reliability.  
           [0009]    Electrical control over vehicles can be implemented by several controllers connected to and communicating over the J1939 bus. Engine controllers and body controllers may be considered to be chief among these devices. These controllers provide programmable digital data processing capacity, which can be exploited to allow both more extensive and more flexible automatic control over vehicles&#39; systems than has heretofore been economically practical.  
         SUMMARY OF THE INVENTION  
         [0010]    The invention provides a vehicle which incorporates a subsystem for the automatic activation and deactivation of vehicle lights, on user request, in a predetermined sequence to assist a single individual in making a sight inspection of operation of the lights. The vehicle includes an electrical system controller including a plurality of energization output ports which may be selectively energized. The lights are connected to the energization output ports of the electrical system controller. The electrical system controller further includes a programmable microcomputer for switching on and off each of the plurality of energization output ports. A test program is provided which is executable on the programmable microcomputer resulting in the sequential activation and deactivation of subsets of the energization output ports connected to lights. The test program further comprises a loop for effecting the sequential activation and deactivation of the energization output ports to repeat.  
           [0011]    Additional effects, features and advantages will be apparent in the written description that follows. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:  
         [0013]    [0013]FIG. 1 is a perspective view of a tractor and trailer combination with which the present invention can be practiced;  
         [0014]    [0014]FIG. 2 is a block diagram of a vehicle controller area network used to implement the invention;  
         [0015]    [0015]FIG. 3 is a high level circuit schematic of an electronic gauge controller, an electrical system controller and a plurality of lamps energized under the control of the electrical system controller; and  
         [0016]    [0016]FIG. 4 is a flow chart illustrating a sequential light actuation system for one embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    [0017]FIG. 1 illustrates in perspective a truck  10  comprising a combination of a tractor  12  and a trailer  14 . Tractor  12  includes the conventional major systems of a vehicle, including an engine, a starter system for the engine, brakes, a transmission and identification lights. Tractor  12  and trailer  14  mount several exterior lamps by which the vehicle provides light for its driver to see by and means to be seen, particularly at night, by others. On the front of tractor  12  are headlights  16 , front corner turn signal lamps  17 , and fog lamps  18 . Several identification lights  21  are installed on the roof of tractor  12 . A lamp box  19  installed on the rear end of tractor  12  carries additional turn signal lights, reverse lights and brake lights. As is common, the forward and tail end turn signal lights have a hazard function and can be cycled on and off together (generally the forward pair together and then the tail end pair together) to provide warning to passing motorists. A pair of electrically activated horns  22  are installed on the roof of tractor  12 . Trailer  14  also carries various lights, including tail end brake and turn signal lamps (not shown), as well as identification lights  23  which may be positioned any where on the trailer, but are commonly found on upper and lower edges of the trailer. Operation of all lamps in all of their possible operational modes is best verified by visual inspection of the lamps in operation.  
         [0018]    Referring now to FIG. 2, tractor  12  includes a network  11  based on an electrical system controller (ESC)  30  and including a shielded twisted pair bus  60  over which data communications between ESC  30  and other controllers occur. An electronic gauge controller  40  and ESC  30  are of primary interest to the invention. Among other vocational controllers and sensor interface modules which may be connected to bus  60  are an automatic transmission controller  50 , an engine controller  20  and an antilock brake system  120 . Collectively, bus  60  and the various nodes attached thereto form a controller area network (CAN).  
         [0019]    Active vehicle components are typically controlled by one of a group of autonomous, vocational controllers. However, most lamps are powered directly from ESC  30 , which includes a number of power field effect transistors (FETs) for that purpose. A switch set  42  for the lamps is attached to EGC  40 , which communicates requests to ESC  30  over bus  60 . Less usually, switches  32  may be directly connected to ESC  30  to provide the same control. A panel display including a plurality of warning LEDs  44  is connected to and under the control of EGC  40 . ESC  30  additionally drives horn transducers  36  mounted in the horns  22  on top of tractor  12 . ESC  30  includes a programmable computer including conventional memory (both volatile and non-volatile) and program execution capacities (CPU  31 , see FIG. 3).  
         [0020]    [0020]FIG. 3 is a high level circuit schematic of EGC  40 , ESC  30 , and a plurality of lamps energized under the control of the ESC as configured for a preferred embodiment of the invention. ESC  30  is a programmable body systems computer used to control many vehicle electrical system functions. In the past, many of these functions were controlled by switches, relays and other independently wired and powered devices. ESC  30  is based on a microprocessor  31  which executes programs and which controls switching of a plurality of power FETs used to actuate vehicle exterior lights and the horn. EGC  40  communicates with ESC  30  over an SAE J1939 data link (bus  60 ) and CAN controllers  43  and  143 . EGC  40  is based on a microprocessor  41  but includes only limited and typically fixed programming. EGC  40  handles switch  45  inputs providing manual control over headlights and enablement of the headlights  16 . Another source of switch inputs may by provided by a switch pack  38  which is connected to microprocessor over an SAE J1708 bus and controller  39  or through switches associated with brake pedals, turn signal levers and other similar systems.  
         [0021]    Activation of a lamp test routine begins with movement of the ignition to the “ON” position, detected by microprocessor  41  of EGC  40 , and with an arbitrary sequence of inputs from other switches connected to microprocessor  31 , including a set of cruise control switches in a voltage divider network  220 , park brake set switch  140  and horn switch  138 . A sequence of actuation of these switches trigger the lamp test cycle. Alternatively, a switch mounted in switch pack  38  may be used to start the lamp test cycle. A preferred trigger sequence of switches is to move the ignition key to the start position, set the parking brake and then simultaneously press cruise on and cruise resume switches followed by depressing the horn button. Cancellation of the cycle comes on a time out condition, or by meeting any number of other conditions, such as moving the ignition to the “OFF” position, tapping the brakes, turning on the headlights, etc. Some of these signals, such as the brake signal may be communicated from ESC  30 .  
         [0022]    Microprocessor  31  can apply activation signals to all of the lamps subject to inspection as well as to a horn coil  36 . In the case of headlights  16 , this may also involve pulling high a headlight enable line by instruction to EGC  40 . Microprocessor  31  is connected to provide an activation signal to a horn power FET  51  which in turn drives a horn coil  36 . Another signal line from microprocessor  31  is connected to drive a park light FET  52  which in turn drives park/tail/marker light bulbs  37 , a license plate ID and mirror light bulbs  38 . Yet another signal line from microprocessor  31  drives a low beam FET  53 , which in turn drives filaments in headlight bulbs  41  and  48 . Low beam FET  53  and park light FET  52  further require an input on the headlight enable line to operate. Still another pin on microprocessor  31  controls a high beam FET  54  which drives high beam filaments in bulbs  41  and  42 . Lastly, a set of four pins on microprocessor  31  are used to control the turn signal lights at each corner of the vehicle. Four FETs  55 ,  56 ,  57  and  58  are connected to receive the signals and, in turn, to power bulbs  43 ,  44 ,  45 , and  46  mounted in turn signal fixtures at the four corners of the vehicle. FETs  55 ,  56 ,  57  and  58  can be activated together or separately to provide turn indications and emergency flasher operation.  
         [0023]    [0023]FIG. 4 is a high level flow chart which illustrates the testing cycle for the lamps and drive circuitry beginning with turning the ignition on and setting the park brake (step  90 ). If the test conditions are not met at step  91  the cycle is never initiated (end step  92 ). However, if the cruise control ON and RESUME buttons are simultaneously hit and the horn activated as determined at step  91 , the testing cycle begins with activating output FETs for the marker lights and work light (if so equipped) for two seconds (step  93 ). Then, the FETs for the marker lights are left on, the FET for the brake lights is activated for two seconds and the work light turned off (step  94 ). Next, at step  95 , the FET for the marker lights are left on, the brake lights turned off, the left turn signal is cycled on and off, the low beams, the work light and fog lamps are activated for two seconds. Next, at step  96 , the left turn signal is canceled, the work light turned off and the right turn signal is turned on. The high beams are turned on. At step  97  all of the lights on at step  96  are turned off and the four bulbs constituting the corner turn lights are flashed in unison (or front to back) to test flasher operation. The work light is turn on again. Finally, at step  98  all of the lights are turned off and the horn is sounded. Next, at step  99  it is checked to determine if the operator has canceled the operation of the test system. This step can occur after each functional step. If operation has not been canceled it may be determined if the process has timed out (step  101 ). Following the YES branch from either of steps  99  or  101  cancels the procedure. The NO branch restarts the cycle. The test loops, causing each set of power FETs to be repeated in the same sequence until cancellation. While in theory the sequence could be varied, a fixed sequence is simpler to implement and use. The time out period is preferably set to about five minutes to provide ample time for the user the view the entire vehicle.  
         [0024]    The present invention enables a vehicle operator to perform a light check of a vehicle with the assistance of a second person. This in turn saves both time and helps insure completeness of the inspection. The test feature can also be used during vehicle manufacture to ensure that electrical connections to exterior bulbs have been correctly made.  
         [0025]    While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.

Technology Category: b