Patent Publication Number: US-2011077827-A1

Title: Work Vehicle Access Monitoring and Control System

Description:
This divisional application claims priority under 35 U.S.C. §120 from co-pending U.S. patent application Ser. No. 11/534,922 filed on Sep. 25, 2006 by M. Javaid Arshad, Zakaria I. Saleh, Prasenjit Adhikari and Michael A. McSweeney with the same title, the full disclosure of which is hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to systems for monitoring and controlling work vehicles. 
     BACKGROUND OF THE INVENTION 
     Computer-based fleet management systems permit operators of large fleets, such as construction and agricultural vehicles, taxicabs, rental cars, rental trucks, and work vehicles, to monitor the location of, and control access to, those vehicles. 
     Access to the vehicles is typically controlled using some combination of vehicle location, typically provided by the GPS receiver, and a coded operator input device that can be manipulated to communicate with the computer controlling the system. An operator is typically provided with a key or other pass card that gives him full and complete access to the vehicle over whatever range he wishes to drive it. The operator either has complete access and control, or none. Such systems, however, do not provide the flexibility needed by those operating vehicles in the construction business. 
     U.S. Pat. No. 5,532,690, for example, discloses a basic geofencing system in which an engine kill switch operates to shutdown the vehicle engine when it leaves a predetermined area. One problem with this arrangement is that the vehicle, when shutdown, is disabled for all further movement. For work vehicles, a sudden irremediable disabling is a problem. For example, the vehicles can block paths or roads. They can prevent the delivery of other materials. If they are disabled from all movement, they may prevent access by other vehicles, and therefore prevent other work from being done at the work site. 
     U.S. Pat. No. 6,249,215, describes a system that provides for gradual reduction in vehicle power when driven outside a predetermined region, but shuts down the vehicle only in predetermined areas. As the vehicle returns to the original area, the power is gradually restored. The system provides for “safe” shutdown in which the vehicle engine is shut down only when it travels to a “safe” shutdown site, such as a gas station. Nothing prevents the vehicle from being driven indefinitely, albeit at a reduced power level. 
     US patent publication 2003/60938 discloses a vehicle geofencing system. The system includes an electronic controller located inside a vehicle that dynamically changes the boundaries of its geofence when commanded by a central computer. The system, however, does not control access to the vehicle, it only controls the frequency with which the vehicle reports to a home base. 
     Similarly, US patent publication 2002/77750 is directed to a system for monitoring the operation of concrete mixing trucks as they travel to and from various job sites. As the vehicles travel, they cross various boundaries and transmit messages to a home base. The system does not disable the vehicle when boundaries are crossed. 
     U.S. Pat. No. 6,204,772 discloses a system for remotely configuring a work vehicle to transmit status information to a remote computer, such as whether it is operating in a particular region. The system does not disable the vehicle. 
     None of the systems described in these references are suited to controlling the operation of work vehicles such as those used on job sites. 
     What is needed is an access control system for construction work vehicles that controls and monitors the operation of the vehicles in the typical construction environment, and that will accommodate multiple job sites. What is also needed is a theft control system for a work vehicle that shuts the vehicle engine down whenever it travels outside the boundaries of one of the job sites. What is also needed is a theft control system that permits the operator to restart the engine after a short interval. What is also needed is a system that prevents the vehicle from traveling between job sites. What is also needed is an elapsed time recording system for a work vehicle that monitors the time spent at each job site, both the vehicle&#39;s actual presence at each job site and the vehicle&#39;s operating time at each job site. It is an object of this invention to provide such a system and method in which these benefits are provided by at least one mode of operation. 
     SUMMARY OF THE INVENTION 
     In accordance with a first aspect of the invention, an access control system for a work vehicle including an engine is provided, including a location sensor on the vehicle configured to provide a location signal indicative of the vehicle&#39;s location; an electronic control unit coupled to the location sensor to receive the location signal, the control unit further including an electronic memory configured to store a plurality of non-contiguous job sites, wherein the control unit is configured to permit operation of the vehicle within the non-contiguous job sites and to disable the vehicle when the vehicle leaves the non-contiguous job sites. 
     The electronic control unit may be configured to shut down the engine when the vehicle leaves the job sites. The electronic control unit may be configurable to prevent the vehicle from being driven from one of the plurality of job sites to another of the plurality of job sites. The electronic memory may store a boundary for each of the plurality of non-contiguous job sites. 
     In accordance with a second aspect of the invention, a theft protection system for a work vehicle including an engine is provided, including a location sensor on the vehicle configured to provide a location signal indicative of the vehicle&#39;s location; and an electronic control unit coupled to the location sensor to receive the location signal, the control unit further including an electronic memory configured to store boundaries of at least one job site, wherein the control unit is configured to shut down the vehicle engine when it leaves the boundaries, and to permit the vehicle engine to be restarted only after a predetermined interval of time. 
     The electronic control unit may be configured to permit the engine to run for only a predetermined period of time after being restarted. The electronic control unit may be configured to permit the engine to the restarted a predetermined number of times. The electronic control unit may be configured to prevent restarts after having been restarted the predetermined number of times. The electronic control unit may be configured to permit the engine to continue running upon restart for as long as it is steered back toward the boundaries, and to shut down the engine after restart if it turns away from the boundaries. 
     In accordance with a third aspect of the invention, an elapsed time recording system for a work vehicle including an engine is provided, including a location sensor on the vehicle configured to provide a location signal indicative of the vehicle&#39;s location; and an electronic control unit coupled to the location sensor to receive the location signal, the control unit further including an electronic memory configured to store the boundaries of a first job site and a first timing counter associated with the first job site, and to store the boundaries of the second job site and a second timing counter associated with the second job site. 
     The location sensor may include a GPS receiver. The electronic control unit may store in the first timing counter a value indicative of the amount of time the vehicle was located at the first job site, and wherein the electronic control unit may store in the second timing counter a value indicative of the amount of time the vehicle was located at the second job site. The electronic control unit may store in the first timing counter a value indicative of the vehicle&#39;s running time at the first job site, and wherein the electronic control unit may store in the second timing counter a value indicative of the vehicle&#39;s running time at the second job site. The electronic control unit may be configured to receive a definition of an additional job site from one circuit selected from a group including a long-range wireless communications circuit, a short-range wireless communications circuit, and a wired computer communications circuit. The long-range wireless communications circuit may be a circuit selected from a group including a cellular telephone and a satellite telephone. The short-range wireless communications circuit may be a circuit selected from a group including a Bluetooth circuit and an 802.11 circuit. 
     In accordance with a fourth aspect of the invention, an access control system for a work vehicle including an engine is provided, the system including means for providing a location signal indicative of the vehicle&#39;s location; and means coupled to the location sensor for receiving the location signal, the receiving means further including electronic means for storing a plurality of non-contiguous job sites, and further including means for permitting the vehicle to operate within the non-contiguous job sites and means for disabling the vehicle when the vehicle leaves the non-contiguous job sites. 
     The means for receiving may include means for shutting down the engine when the vehicle leaves the job sites. The means for receiving may include means for preventing the vehicle from being driven from one of the plurality of job sites to another of the plurality of job sites. The means for storing may be configured to store a boundary for each of the plurality of non-contiguous job sites. The system further includes means for downloading a job site definition. The means for downloading may include one circuit selected from the group including a long-range wireless communications circuit, a short-range wireless communications circuit, and a wired computer communications circuit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a construction work vehicle, shown here as a loader-backhoe, that has a vehicle control system. 
         FIG. 2  is a schematic diagram of the vehicle access control system of the vehicle of  FIG. 1 . 
         FIG. 3  is a schematic diagram showing the construction work vehicle at two job sites, showing the vehicle disabled outside of a job site, and showing the vehicle being hauled from one job site to another job site. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , a work vehicle, here shown as a loader-backhoe  100 , includes a loader attachment  102 , a backhoe attachment  104  and a tractor  106 . The loader attachment  102  and backhoe attachment  104  are pivotally coupled to tractor  106 . Tractor  106  is supported on front wheels  108  and rear wheels  110  for movement over the ground. 
     Vehicle  100  is configured for construction work. Both the loader attachment  102  and the backhoe attachment  104  coupled to and supported by tractor  106  are configured to engage the ground, permitting the vehicle to dig foundations, trench the earth for cables, rip up concrete, transport sand, dirt, and gravel, and carry construction materials around on a job site. It is this configuration which makes the loader-backhoe particularly suited to working at construction sites. It should be understood that the terms “construction vehicle”, “work vehicle” or “construction work vehicle” are not limited to loader-backhoes. A variety of other vehicles including, for example, wheel-loaders, skid steer loaders, trenchers, bulldozers, and graders, among others, are also construction work vehicles. 
     Tractor  106  includes an engine  112  that drives the vehicle over the ground and provides power for the hydraulic cylinders that move the loader and the backhoe. Engine  112  is coupled to a transmission  114 , that in turn drives the rear wheels through differential  116 . Engine  112  is controlled by an electronic governor  118 , which includes an ignition circuit (when engine  112  is a gas engine) or an injector rack controller (when engine  112  is a diesel engine). Electronic governor  118  is capable of regulating the speed of engine  112  and of turning engine  112  on and off. 
     Tractor  106  includes a hydraulic pump  120  that is coupled to engine  112  and is driven thereby. Hydraulic pump  120  provides hydraulic fluid to cylinders, including loader arm lift cylinders  122  and loader bucket cylinders  124  of loader attachment  102 , as well as boom swing cylinders  126 , boom cylinder  128 , dipper cylinder  130 , and backhoe bucket cylinder  132  of backhoe attachment  104 . These cylinders move the loader bucket and the backhoe bucket permitting them to engage the ground. When engine  112  is turned off, the backhoe  102  and loader  104  attachments are disabled. When engine  112  is turned on, the backhoe and the loader attachments  102 ,  104  are enabled. 
     Tractor  106  also includes a vehicle access control system  134  coupled to the engine for (1) determining the vehicle&#39;s location, (2) disabling the engine (e.g. turning it on and off) based upon the vehicle&#39;s location, and (3) responding to signals provided by the engine (e.g. by governor  118 ) that the engine is running; and (4) logging engine hours. 
       FIG. 2  illustrates vehicle access control system  134  in more detail. System  134  includes (1) an electronic control unit or ECU  135 , (2) a location sensor, here shown as satellite navigation receiver  136 , that is coupled to ECU  135 , (3) a long-range wireless communications circuit  138  coupled to ECU  135 , (4) a short-range wireless communications circuit  140  coupled to ECU  135 , and (5) a computer communications circuit  142  for communicating with other ECUs or controllers on the vehicle as well as digital computers that are brought to the vehicle and connected to circuit  142 . 
     ECU  135  is a digital microprocessor-based control unit, whose functioning controls the operation of the other components  136 ,  138 ,  140 ,  142 . In the preferred embodiment, shown here, a single ECU is coupled to all of the communications circuits and the location sensor. 
     ECU  135  may be coupled to other circuits and sensors in addition to the circuits shown here. It may also be programmed to perform additional functions not described herein. In an alternative configuration, several ECU&#39;s may be interconnected to collectively perform the functions described herein. In this alternative configuration, each ECU may be coupled to one of the communications circuits and sensor circuit and coordinate its activities with the other ECU&#39;s over a network that interconnects these ECU&#39;s. 
     Location sensor  136  provides a signal indicating the location of the vehicle in at least two dimensions (e.g. latitude and longitude, or other similar coordinate system), and thus whether the sensor (and by extension the, the vehicle) is inside or outside of to dimensional job site boundaries. Alternatively, sensor  136  can provide a signal indicating the location of the work vehicle in three dimensions. In its preferred embodiment, sensor  136  is responsive to navigation signals provided by satellites and generates a signal indicating the location of sensor  136  (and hence of vehicle  100 ). This navigation signal is transmitted to ECU  135 , which is configured to determine the location of the vehicle based upon the navigation signal. 
     Long-range wireless communications circuit  138  is configured to provide long-range wireless telecommunications. In its preferred embodiment, circuit  138  communicates with long-range wireless communication networks, such as cellular phone networks  137  or satellite phone networks  139 . ECU  135  is configured to transmit location data and other data to a remote fleet management computer  141  over circuit  138 . 
     Short-range wireless communications circuit  140  is configured to provide short-range wireless telecommunications. In its preferred embodiment, circuit  140  is configured to communicate with other digital computers located within, adjacent to, or nearby the vehicle. Circuit  140  may comprise such short-range radio communication circuits as Bluetooth devices, or IEEE 802.11 devices, such as WiFi transceivers. 
     Computer communications circuit  142  is configured to provide short-range wired communications. In its preferred embodiment, circuit  142  communicates with digital computers or ECU&#39;s located within, adjacent to, or nearby the vehicle. Circuit  142  may comprise an Ethernet circuit, Token Ring circuit, AppleTalk circuit, RS-232 or other serial communications circuit, parallel communications circuit or other circuit for digital communications between ECU  135  and other ECU&#39;s, controllers, or digital computers that couple thereto by electrical or optical conductors. 
       FIG. 2  also illustrates internal details of the components of ECU  135  which include a CPU  144 , random access (RAM) memory  146 , non-volatile (ROM) memory  148 , and an I/O circuit  150 , which are coupled together by a control/data/address bus  152 . 
     CPU  144  is a digital central processing unit whose operation is controlled by digital instructions stored in non-volatile memory  148 . Nothing herein should suggest that CPU  144  performs only the functions described herein. CPU  144  may perform other functions that are not described herein. In an alternative configuration, several CPU&#39;s may be interconnected to collectively perform the functions described herein. Each CPU may have its own memory circuits and I/O circuit, or may share these circuits with other CPUs. Furthermore, the ECU  135  may have more than the one CPU, RAM, ROM and I/O circuit illustrated herein. 
     CPU  144  executes instructions stored in ROM memory  148 . These instructions control the operation of control system  134 . This operation is described below in conjunction with  FIG. 3  . 
     RAM memory  146  provides temporary storage space for variables and other computational results as system  134  operates. Memory  146  receives and stores data that CPU  144  generates as CPU  144  executes the instructions stored in non-volatile memory  148 . 
     RAM memory  146  is preferably nonvolatile, capable of storing data even when the operational power normally provided to ECU  135  is turned off. RAM memory  146  holds many numeric values used during the operation of the vehicle. In particular, RAM  146  is configured to hold several values that ECU  135  uses to perform the functions described below. RAM  146  stores a list of job sites in which vehicle  100  is authorized to operate. RAM  146  stores the boundaries of these authorized job sites in a form that permits CPU  144  to determine whether vehicle  100  is inside or outside of the job sites&#39; boundaries when ECU  135  given the vehicle&#39;s location by location sensor  136 . Whenever vehicle  100  is authorized to operate at an additional job site, new job site boundaries are downloaded and a new job site defined by those boundaries is added to the job site list. ECU  135  is programmed to download the job site and their boundaries from remote fleet management computer  141  over circuit  138  or from a computer  143  located adjacent to vehicle  100  and configured to communicate with vehicle  100  wirelessly via circuit  140  or via a conductor coupling computer  143  and circuit  142 . RAM  146  also stores, for each job site, an amount of time that vehicle  100  is authorized to operate at that job site. RAM  146  (or, alternatively, memory  148 ) includes memory locations in which ECU  135  records several different time values indicating, respectively, (1) the amount of time the vehicle was at the job site, (2) the amount of time the vehicle was operating, (3) the amount of time the engine was running, (4) the amount of time the vehicle was moving, and (5) the amount of time the backhoe or loader attachments were moving or otherwise being used. An signal indicating the time the engine is running is provided to ECU  135  by governor  118 . An indication that the various controls are being operated (and hence of the interval over which they are operated) can be provided by switches coupled to the controls and to ECU  135  to sense their manipulation by the operator (and hence sense the use of the hydraulic elements of the vehicle). Vehicle movement can be sensed by switches in the transmission responsive to gear engagement, that are coupled to ECU  135 . Alternatively vehicle movement can be determined by ECU  135  monitoring changing vehicle position indicated by position sensor  136 . 
     I/O circuit  150  is coupled to sensor  136  and circuits  138 ,  140 ,  142  and is configured to provide the signals and data they generated to CPU  144  for the CPU for use in performing the operations described herein. 
     Engine Disabling when Leaving Job Sites 
       FIG. 3  illustrates the operation of control system  134  of vehicle  100 . In  FIG. 3 , vehicle  100  is shown in four different locations ( 100 A,  100 B,  100 C, and  100 D), each location illustrating the vehicle at a different place during normal vehicle operation. The discussion below explains how control system  134  operates when vehicle  100  is located at these different locations. 
     When vehicle  100  is at first location  100 A it is located within boundaries  156  of a first job site  154 . The second location  100 B shows vehicle  100  located adjacent to but outside the boundaries  156  of job site  154 . The third location  100 C shows vehicle  100  located on a trailer  158 , which is in the process of transporting vehicle  100  from first job site  154  to a second job site  160  defined by boundaries  162 . The fourth location,  100 D, shows vehicle  100  located within the boundaries  162  of the second job site  160 . 
     ECU  135  on vehicle  100  is programmed to continuously (1) determine the location of the vehicle by reading location sensor  136 , receiving from it a signal indicative of the vehicle position, and (2) selectively disable the vehicle when it travels outside the boundaries of the job sites as determined by comparing the position signal with the job site boundaries in ECU memory and shutting own the engine. ECU  135  disables the vehicle by shutting down engine  112 . Thus, when vehicle  100  is at location  100 A within the boundaries of the first job site  154 , ECU  135  permits the vehicle and the engine to operate by not disabling the engine  112 . 
     Vehicle  100  can be driven across boundaries  156  and out of job site  154 , to location  100 B. When vehicle  100  is driven to this location, ECU  135  is configured to (1) determine that the current location of vehicle  100  is outside of the boundaries of job site  154 , and based upon this determination (2) shut down engine  112 , thereby disabling vehicle  100 . 
     Generally speaking, in order to shut down engine  112  and disable vehicle  100 , control system  134  transmits a signal to engine governor  118  ( FIG. 1 ) signaling the governor to disable the ignition (if engine  112  is a spark ignition engine) or to reduce the rack position to zero (if engine  112  is a diesel engine). Alternatively, control system  134  can shut down engine  112  by shutting off the fuel supply (e.g. by disabling the fuel pump or closing of valve disposed in the fuel line) or shutting off the air supply (e.g. by closing a throttle plate or other air valve that controls the flow of air to engine  112 . Control system  134  is configured to determine whether engine  112  is running are not. Engine governor  118  signals control system  134  that it is running over signal lines that couple the two together. 
     Limited Restarting to Return to Job Site 
     In the section above, we described how the operator may drive the vehicle outside of either of the job site boundaries  156 ,  162 , and how when this happens, ECU  135  is configured to shut down the engine. On occasion, however, the operator may unintentionally drive the work vehicle outside of the job site boundaries. In these instances, the operator will wish to start to vehicle up and return it to the job site as soon as possible. ECU  135  is configured to permit a limited number of engine restarts and limited operation. By permitting a limited number of engine restarts, the operator is given time to drive the vehicle back into the job site, or (alternatively) to move the vehicle to a more secure location outside of the job site. 
     Permitting the vehicle to be restarted, even if only for a limited time, raises the possibility that a thief could repeatedly restart the vehicle  100 , drive it a short distance before it is disabled, then repeat the process until the vehicle is far away. To reduce the chance of this occurring, ECU  135  is configured to prevent the vehicle&#39;s engine from being restarted for a predetermined interval of time, called a “restart delay interval”. If the operator attempts to start the engine during this time interval, ECU  135  prevents the engine from starting. Only after the restart delay interval has passed will ECU  135  enable the vehicle and permit the vehicle to be restarted. The restart delay interval is preferably 30 seconds long. 
     Once the restart delay interval has passed, ECU  135  permits the engine  112  to be restarted by re-enabling whatever vehicle systems it had previously disabled to prevent restarting. As mentioned above, these vehicle systems preferably include rack position, air supply, fuel supply, or ignition. 
     ECU  135  does not permit the engine to run indefinitely once it is restarted, however. ECU  135  monitors the location of the vehicle, recognizes that it is still outside the job site, and permits the engine to run for only a second predetermined time interval called a “restart run interval”. The restart run interval is preferably 30 seconds. 
     Having restarted a previously disabled vehicle outside the jobsite boundaries  156 ,  162 , if the operator does not drive the vehicle back within the boundaries of the job site within the restart run interval, ECU  135  is programmed to shut down the engine again. Once ECU  135  shuts down the vehicle a second time, ECU  135  is programmed to repeat the delay process and again prevent the engine from restarting for another restart delay interval. Once the restart delay interval has passed again, the operator can again restart the vehicle and again operate it for another restart run interval. 
     ECU  135  is configured to repeat this engine-starting and engine-stopping process a predetermined number of times, preferably four, permitting the operator each time to return the vehicle to within the boundaries of the job site. Once this starting/stopping process has been repeated the predetermined number of times, ECU  135  is configured to totally disable engine  112 . 
     ECU  135  maintains an internal counter in memory  146  or  148 . Each time the vehicle is restarted, ECU  135  increments this counter. Before restarting the vehicle, ECU checks this counter to see whether the counter has reached a maximum number of restarts. Whenever ECU  135  determines that the counter has reached the maximum number of restarts, the ECU disables the vehicle by preventing any further restarts. Thus, ECU  135  permits only a limited and predetermined number of restarts. If the operator has not returned to within the boundaries of one of the job sites listed in ECU  135  memory before this limit is reached, the vehicle will remain disabled and outside the boundaries of the job sites. 
     Subsequent efforts to restart the engine, for example, by the operator using the ignition switch or other standard starting means, will not work. If the vehicle has been returned to within the job site boundaries sometime during the predetermined number of engine restarts, the vehicle will again operate as normal within the boundaries of the job site. Only after ECU  135  restarts the vehicle the predetermined number of times outside the job site boundaries before returning to the job site will the vehicle be disabled and not restart. 
     To enable the vehicle again after it has had its maximum restarts, ECU  135  is programmed to respond to a special reset signal transmitted to it from a computer coupled to the long-range communications circuit  138 , the short-range communications circuit  140 , or the wired computer communications circuit  142 . 
     ECU  135  is programmed to receive the reset signal and responsively return to its original operating mode in which it periodically tests whether it is within one of the plurality of predetermined noncontiguous job sites. 
     It should be clear from this description that control system  134  is configured to prevent a work vehicle from being driven from one job site where it is enabled to operate to another distant job site where it is also enabled to operate. Any attempt to drive the vehicle between two noncontiguous job sites would cause the engine to shut down as described above. Of course, if the two job sites were immediately adjacent to each other, or touching each other, the operator would be able to drive from one job site to another. 
     In order to move work vehicle  100  from one job site to a distant and non-contiguous job site, the work vehicle  100  must be towed or carried. It cannot travel under its own power. Since the job sites are not joined together—i.e. not contiguous—there is no way to get from one job site to the other without the engine automatically shutting down. It is the region between the two job sites in which control system  134  shuts the engine down. This prevents vehicle  100  from traveling between job sites under its own power. A vehicle traveling on a trailer does not travel under its own power, and therefore does not need to have its engine running. 
     This is the situation indicated by vehicle  100  at location  100 C. At location  100 C, vehicle  100  is shown loaded on trailer  158  with the trailer carrying the vehicle from job site  154  to job site  160 . In the preferred process, vehicle  100  is loaded on trailer  158  within the boundaries of first job site  154 . Since vehicle  100  is within the confines of first job site  154  during this loading process, control system  134  permits the engine of the vehicle to operate and permits the operator to drive vehicle  100  onto trailer  158 . Once vehicle  100  is on trailer  158 , the operator turns off engine  112  of vehicle  100  and readies vehicle  100  for transport. 
     The operator can then enter the cab of the vehicle  159  that is coupled to and pulls trailer  158  and carries trailer  158  together with vehicle  100  across the boundaries  156  of first job site  154 . 
     The operator can tow vehicle  100  on trailer  158  from first job site  154  to second job site  160  whether engine  112  of vehicle  100  is running or not. If engine  112  of vehicle  100  is indeed running when trailer  158  leaves the boundaries of the first job site, control system  134  will shut down engine  112  as described above. Since vehicle  100  is already on trailer  158 , however, disabling the vehicle and shutting down engine  112  will not prevent vehicle  100  from being carried from one job site to another and from being restarted inside the new job site boundaries once it arrives. 
     Transportation is not limited to the two job sites illustrated in  FIG. 3 . Additional job sites and corresponding boundaries may be recorded in ECU  135 , such as work sites, maintenance facilities, repair depots, storage lots, or other locations. 
     Returning to the example of  FIG. 3 , the operator eventually arrives at second job site  160  with trailer  158  and vehicle  100  in tow. The operator tows trailer  158  and vehicle  100  until they are within the boundaries  162  of job site  160 . Once within the boundaries of the job site, vehicle  100  can be started, and will run continuously. It is then driven off the trailer and operated at job site  160  to perform work. 
     ECU  135  is configured to determine whether vehicle  100  is at any of a plurality of job sites, and to permit operation only at those job sites. It uses the vehicle&#39;s position, which is derived from location sensor  136  and the boundaries of each of the plurality of job sites stored in the electronic memory of ECU  135  to determine where the vehicle is. When vehicle  100  is started at the second job site  160 , ECU  135  senses that vehicle  100  is within the boundaries  162  of the second job site  160  and permits the operator to start and run vehicle  100 . ECU  135  is configured to automatically and periodically check the location of vehicle  100  at the second job site  160  just as ECU  135  did at its first job site  154 . Since both job sites are defined in the memory of control system  134  as authorized regions of operation, ECU  135  is configured to not disable vehicle  100 , but to permit vehicle  100  to operate at the second job site as well. 
     If the operator drives vehicle  100  across the boundaries  162  of second job site  160  and outside of the job site  160 , control system  134  will perform the identical functions it performed at job site  154 . It will identify that vehicle  100  is no longer within the boundaries of any job site and will disable vehicle  100  by turning off engine  112 . 
     Self-propelled travel by vehicle  100  between the two job sites is therefore prevented. A vehicle starting at a first job site cannot exit that job site and travel to a second job site, and a vehicle at the second job site cannot exit that job site and travel to the first job site. The vehicle is configured to permit operation at both of those job sites and to prevent it from being driven between the job sites. 
     Right of Return to Job Site 
     The control system  134  is configured to permit the operator to return to vehicle to a job site it inadvertently left. It does this by monitoring the location of the vehicle. As long as vehicle  100  follows a path calculated by control system  134  to return to a job site that the vehicle just departed, ECU  135  will not disable the vehicle, but will permit it to keep operating. 
     Referring to  FIG. 3 , if the work vehicle starts at location  100 A inside job site  154 , and is driven across boundary  156  until it is outside job site  154  at location  100 B, ECU  135  will shut down the vehicle&#39;s engine. This was described above. After a predetermined time interval, the operator will be permitted to restart the vehicle, also as described above. In this alternative configuration, ECU  135  is configured to permit the vehicle to return to job site  154  from which it immediately departed without disabling the engine after a predetermined time duration as described above in the Limited Restart section. 
     Instead, ECU  135  determines the direction of travel of the vehicle and permits the vehicle to keep operating as long as the vehicle is traveling in a direction back toward job site  154 . When the vehicle is restarted, ECU  135  begins a timer to determine whether the restart run interval has been exceeded as described above in the Limited Restart section. In the Right of Return configuration, however, as soon as ECU  135  determines that the vehicle is pointing back toward job site  154 , ECU  135  stops determining whether the vehicle has exceeded the restart run interval. Instead, as long as the direction of travel is directed back toward boundary  156  and job site  154 , ECU  135  will permit engine  112  to continue running. It will not shut down engine  112  after the restart run interval has expired. However, should the operator turn vehicle  100  away from boundary  156 , thereby driving the vehicle in a direction that increases the distance between vehicle  100  and job site  154 , ECU  135  will shut down engine  112 . 
     Time Logging 
     Another feature of ECU  135  of control system  134  is its ability to keep a running total of the time the vehicle spends on site for each job site, a running total of the time the vehicle engine runs on site for each job site and a running total of the time the vehicle spends operating anywhere, and its ability to shut down vehicle  100  when any (or all) of these totals exceed an associated predetermined amount. 
     For example, ECU  135  is programmed to store in nonvolatile memory  148  a predetermined vehicle time limit for presence at each job site, a predetermined vehicle time limit for engine running at each job site, a predetermined vehicle time limit for vehicle movement at each job site, and a predetermined vehicle time limit for implement operation at each job site. Each job site has a corresponding set of these time limits. 
     ECU  135  is programmed to maintain timers for each of the three running totals in nonvolatile memory  148  and to periodically increment these timers as appropriate. When vehicle  100  is in job site  154 , ECU  135  increments a presence timer, and engine running timer, a vehicle movement timer, and an implement operation timer that are associated with job site  154 . Similarly, when vehicle  100  is in job site  160 , ECU  135  increments a presence timer, an engine running timer, a vehicle movement timer, and an implement operation timer that are associated with job site  160 . 
     Further, ECU  135  is programmed to respectively compare the predetermined time limits with the timers, and to disable the vehicle if any of the predetermined time limits are exceeded. 
     Even further, ECU  135  is configured to disable the vehicle by shutting the engine down for exceeding the time limits. 
     ECU  135  increments the timers based upon its current location. Whenever tractor  100  is in a particular job site, ECU  135  increments the timers associated with that job site and not the timers associated with the other job sites. ECU  135  increments the timer associated with total vehicle operating time whenever the vehicle operates, and regardless of where it is operating. Thus, there are both timers specific to operation at each individual job site and a timer associated with operation anywhere. 
     When the vehicle changes from one job site to another, ECU  135  is configured to sense this change in position and to switch to the timers appropriate for that job site, and to periodically update them, typically on the order of once every 10 milliseconds to once every few minutes. Unlike prior art systems in which a single timer is maintained that indicates the total operating time of the vehicle, control system  134  maintains multiple timers, each timer being associated with a different and non-contiguous area (in this case different job sites). 
     ECU  135  further includes a timer that includes overall engine running time, no matter where vehicle  100  is located. ECU  135  is configured to increment this timer whenever the vehicle&#39;s engine runs, no matter where the vehicle is located. 
     Thus the areas associated with some timers are discrete and non-contiguous (i.e. timers for different job sites), some timers overlap each other in area, but are not coextensive in area (i.e. any job site engine running timer and the overall engine running timer), some timers are coextensive in area, but not coextensive in time (i.e. the timer indicating the vehicle&#39;s presence at a job site A and the timer indicating the vehicle&#39;s engine running time at job site A). 
     Providing multiple operating times for several different jobsites and an overall engine running time is particularly beneficial with work vehicles, which may be authorized to work on jobs at several different job sites. Construction work vehicles are often shifted between job sites unexpectedly. Initial construction plans may anticipate that a skid steer loader or loader-backhoe (for example) is required at a job site at a particular time to do a particular task. These tasks are often estimated at a predetermined number of hours, and customers of the builder or contractor are charged accordingly. It is often undesirable for a work vehicle to be used a worksite for more than the predetermined and bargained-for period of time. 
     To enforce these time or use limits, control system  134  is configured to maintain a plurality of time records indicating the permitted use limits and actual use of vehicle  100  at a plurality of job sites. Using the example of  FIG. 3 , for example, vehicle  100  can be programmed with the permitted amount of time vehicle  100  may operate at both job sites. In this manner, the contractor or builder can keep track of the operating hours of work vehicles at two different job sites for two different clients, without having to maintain separate sets of books or rely on manually entered operator records. Further, the operator can contract with customers for a predetermined amount of time the vehicle can be used and leave the particular date and time at which that use will occur open for later adjustment. 
     For example, if a construction company with a backhoe agrees to dig two foundations for two different customers at two different job sites and negotiates a different number of total hours for each customer, control system  134  can be configured to keep track of these hours no matter when the hours are worked. Using the example of  FIG. 3 , the owner of vehicle  100  can contract to dig a foundation at job site  154  in 20 hours. The owner of vehicle  100  can also contract to dig a foundation at job site  160  in 30 hours. The boundaries of these two job sites and the hours allotted for each job can be recorded in the nonvolatile memory  148  of control system  134 . With these limits programmed into control system  134 , vehicle  100  can be moved to job site  154  and the operator can commence work. ECU  135  monitors location sensor  136  and increments the elapsed engine running time timer in the memory  148  of ECU  135  as the vehicle works. ECU  135  is configured to periodically compare this elapsed engine running time to the predetermined time limit of 20 hours allotted for that job which is also stored in memory  148 . When vehicle  100  is worked for the agreed-upon and programmed with 20 hours, ECU  135  is configured to shut down engine  112  of vehicle  100  and prevent further work at that job site. With the work complete at job site  154 , vehicle  100  can be transported from job site  154  to job site  160  on trailer  158 , and can then commence work at job site  160 . ECU  135 , following the same logic, will monitor location sensor  136  and increment the elapsed engine running time timer in the memory  148  of ECU  135 . ECU  135  is configured to periodically compare this elapsed engine running time at job site  160  to the 30 hours allotted for that job, which is also stored in memory  148 . When vehicle  100  has worked for the agreed-upon and programmed 30 hours, ECU  135  will shut down engine  112  of vehicle  100 . 
     The foregoing paragraph is just one example. The flexibility of the system, however, rests in its ability to simultaneously maintain both job site boundaries and associated timers in memory  148  and permit operation at either job site in any order, and at any time, until the predetermined allotted time for operation at each particular job site has elapsed. For example, and as is often the case at construction work sites, work may be delayed at one job site for sudden and unanticipated reasons: another contractor may not perform his preparatory work, bad weather may prevent vehicle  100  from working outside, or governmental approvals may be delayed. Whatever the reason, vehicle  100  can easily accommodate these delays by ceasing operations at one job site before its total allotted time at that job site has expired, and beginning work (or continuing work) and another job site. 
     As one illustrative example assume that the operator stops working after having worked only five hours at job site  154 . ECU  135  has kept an ongoing record of the elapsed engine running time at job site  154 , and thus stores data indicative of the time worked (five hours) as well as the total engine running time permitted at that job site (20 hours). 
     The operator can then load vehicle  100  onto trailer  158  and move it to job site  160 , the alternative job site where vehicle  100  is also (using the example above) programmed to perform 30 hours of work. Upon arrival at job site  160 , vehicle  100  can be started and will operate for up to 30 hours within the boundaries of job site  160 . ECU  135 , determining that vehicle  100  is within the boundaries of job site  160 , will increment the timers for work performed at job site  160 , and not increment the timers for work performed at job site  154 . As the operator operates vehicle  100  at job site  160 , ECU  135  periodically monitors location sensor  136  and determines that vehicle  100  is operating at job site  160 . ECU  135  is programmed to increment the timer that indicates the elapsed operating time at job site  160 . If work at job site  160  is delayed, after (for example) 10 hours of work has elapsed, the operator can load work vehicle  100  back on trailer  158  and return to job site  154 . When the engine of vehicle  100  is started at job site  154 , ECU  135  monitors location sensor  136 , determines that vehicle  100  is back at the original job site  154 , and updates the elapsed engine running time timer for job site  154 . In this example, since five hours of operation have already elapsed at job site  154 , control system  134  now updates the elapsed engine running time timer for job site  154  starting with the previously elapsed five hours and permits an additional 15 hours of engine running time at job site  154  until the total operating time at job site  154  is consumed, at which time ECU  135  shuts down the engine. 
     ECU  135  periodically compares the elapsed operating time at each job site with the predetermined operating time at that job site. When the elapsed time equals or exceeds the predetermined operating time, ECU  135  disables the vehicle  100 . This disabling is done on a job-site-by job-site basis. In other words, vehicle  100  can meet the predetermined operating time limit for one job site, and ECU  135  will responsively disable the vehicle at that job site, preventing further operation at that job site. The vehicle will still be capable of operation at other job sites for which vehicle  100  has not reached its corresponding operating time limits. 
     When and how often vehicle  100  travels back-and-forth between job site  154  in job site  160  is at the operator&#39;s discretion. Since ECU  135  knows immediately what job site it is working at based upon what preprogrammed job site boundary it is within, based upon the signal from the location sensor, ECU  135  always knows which job site timing counter should be incremented, and whether the permitted time of operation has been exceeded. 
     Programming Boundaries and Operational Times 
     In the preferred configuration, control system  134  stores both the boundaries and the operational time associated with each boundary as well as the various timers that are incremented in the memory of ECU  135 . ECU  135  is configured to store not just two job sites and job site boundaries and associated timers, as illustrated herein, but as many job sites as can be contained in the memory of ECU  135 . 
     Maintaining all jobsite information in the memory of the vehicle&#39;s ECU permits vehicle  100  to operate independently of any centralized fleet management system—at least until the various time limits are exceeded and the vehicle is ultimately disabled. In the process described in Time Logging, above, ECU  135  determines that the vehicle is or is not within a boundary and has or has not consumed its hours at each job site by examining the location provided by location sensor  136  and comparing it with the boundaries and the permitted maximum number of hours of presence, running, or operating for that job site, which are stored in memory  148 . 
     These boundaries and operational times can be programmed using any of (1) the long-range wireless communications circuit  138 , (2) the short-range wireless communications circuit  140 , and (3) the wired computer communications circuit  142 . ECU  135  is programmed to communicate with another computer having the jobsite boundary and jobsite maximum time data by any one of these links. 
     In one configuration, the operator can bring a portable computer device  143  ( FIG. 2 ) with a short-range wireless connection such as an 802.11x or Bluetooth transceiver in close proximity to the vehicle and can transmit the boundary and operational time data for one or more job sites directly from the handheld computer device to ECU  135  via short range circuit  140 . 
     In another configuration, the operator, using a remote computer device  143  ( FIG. 2 ) with a cellular phone or satellite phone connection, can dial the corresponding cellular phone or satellite phone circuit of the long-range wireless communications circuit  138  and transmit the boundary and operational time data for one or more job sites to ECU  135 . 
     In yet another configuration, the operator can go to vehicle  100  and make a wired connection between a portable computer device  143  and wired communication circuit  142  of ECU  135 . Once this connection is made, the operator can transmit the boundary and operational time data to ECU  135 . 
     The description above is provided to illustrate particularly preferred embodiments of the invention. What is new, however, and what is protected by the claims below is not limited to the particular machines and processes described above. The invention may cover more than the particular machines and methods described above. The claims below are intended to communicate the actual scope of the invention and what is protected from infringement. 
     Certain modifications can be made to the machines and processes above while still falling within the scope of the claims below.