Abstract:
A method of controlling fleet vehicles includes the steps of identifying transmitter signals from a select group and an entire group to allow selective operation of certain specific vehicle functions. The method also includes the step of reprogramming a secret key and storing the previous secret key such that transmitters that have not already been programmed can be programmed if they include the old secret key.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    The application claims priority to U.S. Provisional Application No. 60/819,791 and 60/833,887 which were both filed on Jul. 10, 2006. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention generally relates to a remote entry and start system for fleet vehicles. More particularly, this invention relates to a method of programming and operating a keyless entry and start system for fleet vehicles. 
         [0003]    Typically, one or two remote transmitters known as a fob are mated with a single vehicle. The fob and the vehicle controller include identification codes that are used to authenticate transmissions before recognizing and performing the desired operations. However, in fleet applications where many vehicles are operable by many fob&#39;s, storage of every applicable identification code, and then comparing received identification codes with the stored codes unacceptably increases wait times. Additionally, not comparing identification codes and providing operation of many different fobs with many different vehicles can result in actuation of a vehicle function, for example unlocking of the doors, for all the vehicles within a fobs transmission range. 
         [0004]    Additionally, programming and reprogramming multiple fobs for use with many vehicles also presents a problem where secret codes are utilized to verify authorization to operate any specific vehicle. Old key fobs that have not yet been updated, and do not include the current secret key are not recognized by a vehicle controller and therefore cannot be easily updated. 
         [0005]    Accordingly, it is desirable to design and develop a method and system for operating and programming multiple fobs with multiple vehicles. 
       SUMMARY OF THE INVENTION 
       [0006]    An example system and method of controlling fleet vehicles with a number of different remote transmitters includes the steps of determining the origin of a transmission providing selective access to a certain vehicle functions dependent on the origin of the signal. 
         [0007]    The example immobilizer system provides for operation of a fleet including a plurality of vehicles each including a vehicle controller that communicates with a corresponding plurality of transmitters known commonly as a key fob. Each of the key fobs includes a secret key code common to all vehicles within the fleet along with an identification code unique to each fob. A select level of access is allowed for all vehicles in the fleet responsive to received instructions from any fob within the fleet that includes the secret key code. A select second group of fob identification codes are stored within a corresponding select group or single vehicle within the fleet. Transmissions including an identification code that is stored within the vehicle controller provides for an increased level of control and access. If the transmission includes an identification code that does not match then only limited access is allowed. 
         [0008]    The example system and method also operates to provide reprogramming of secret key codes for many vehicle controllers and transmitters. Transmitters that include either the current secret key or an old secret key are recognizable by a vehicle controller and therefore are reprogrammable. 
         [0009]    These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a schematic representation of the example method of controlling operation of select vehicles within a fleet of vehicles. 
           [0011]      FIG. 2  is a schematic flow diagram of the method of controlling select vehicles and controlling access to select transmitters of a vehicle fleet control system. 
           [0012]      FIG. 3  is a schematic representation of a method of re-programming secret keys for a fleet system. 
           [0013]      FIG. 4  is a flow diagram illustrating the example steps for re-programming a secret key for a fleet of vehicles. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0014]    Referring to  FIG. 1 , an example fleet of vehicles includes a first group  12 . The first group  12  includes all the vehicles  10  within the fleet. A second group  14  is defined within the first group  12  and includes a lesser number of vehicles  10 . In the illustrated example, only one vehicle is illustrated as belonging to the second group  14 , however, several vehicles may belong to the second group  14 . Each of the vehicles  10  includes a vehicle controller  22 . Each vehicle controller  22  includes a memory device and location  24  that stores a number of identification codes less than all of the identification codes within the example fleet. The vehicle  10  within the second group  14  includes two identification codes  38 ,  40 . Each identification code corresponds to a transmitter  26 . The transmitters  26  are also divided into a first group  18  and a second group  20 . The first group  18  includes all the transmitters within the fleet that include the proper secret key. Each of the transmitters within the first group  18  is able to selectively actuate certain specified functions of each of the vehicles  10 . 
         [0015]    The second group  20  is smaller than the first group  18  and includes transmitters that correspond to the second group of vehicles  14 . The common link between the transmitters  26  in the second group  20  and the vehicles  10  within the second group  14  is that the vehicles  10  within the second group  14  have stored in the vehicle controller memory devices  24  the identification codes  38 ,  40  that correspond to the transmitters  26  within the second group  20 . Each of the vehicles  10  stores a limited number of identification codes corresponding to certain transmitters within a corresponding group. When a transmission from those specific transmitters  26  is received the received identification code is matched with identification codes stored within the vehicle controller memory  24  to verify the level of access and control authorized. 
         [0016]    In the example system, each of the transmitters  26  is operable to actuate a driver&#39;s side door  34  and to start the engine of each of the vehicles within the first group  12 . As the first group  12  includes all of the vehicles within the fleet, each of the transmitters  26  is authorized to control access to the driver side door  34  and start the engine. This limited access provides the desired functionality of each of the vehicles  10  while limiting access and controlling operation of several vehicles at the same time. As appreciated, if each transmitter had full authorization of each of the vehicles, any transmission from any transmitter  26  could possibly cause operation of several vehicles within range of the transmission. Such operation may not be desirable in specific instances. 
         [0017]    Referring to  FIG. 2 , a first step of operation at the vehicle controller  22  begins upon receipt of the transmission  42  from one of the transmitters  26 . The incoming transmission  42  is evaluated first to determine if it is a valid transmission from at least the first group of transmitters  18  as is indicated at step  44 .The transmission  42  can be verified in many different ways. In the example system, a secret key is utilized along with an encrypted signal to provide verification of the incoming signal  42 . 
         [0018]    Once the incoming signal has been validated, it is determined if an identification code included with the signal  42  matches identification codes that are stored within the vehicle controller memory  24  as indicated at step  46 . If the identification code does not match any of the identification codes stored in the vehicle controller  22 , then the instructions provided or transmitted with the signal  42  is evaluated. That evaluation occurs as is illustrated in block  48  to determine if the desired operations fall within the limits and parameters that are allowed for a transmitter within the first group. In this example, the allowed operations are to unlock the driver side door and allow operation of the engine. If any other commands are received then those would fall outside of the allowed and acceptable performance from instructions received and no operation would occur at the vehicle  10 . However, if the operation is either unlocking the door or operation of the engine then that function is actuated as is indicated at block  52 . 
         [0019]    Referring back to block  46 , if the identification code is recognized by the vehicle then any functions or instructions that are received by transmitter  26  will be actuated as indicated by block  50 . The vehicle controller  22  then returns to an exit block  54  then returns back to the validation of any incoming transmissions that it may receive. 
         [0020]    Referring to  FIGS. 3 and 4 , each transmission from the plurality of transmitters  26  includes an encrypted portion and an unencrypted portion. The encrypted portion is encrypted according to an algorithm that utilizes a secret key along with other data including identification data and button actuation data to prevent unauthorized duplication of transmissions. Along with the encrypted data is unencrypted data including all of the information transmitted within the encryption except for the secret key. The vehicle controller  22  of each vehicle  10  in which the transmitter is authorized to operate includes a corresponding secret key. The secret key is never transmitted over open airwaves and is utilized upon receipt of transmission to verify that that transmission is from an authorized transmitter. In vehicle fleet applications, a secret key is often required to be re-programmed in each of several vehicle controllers  22  and corresponding transmitters  26 . Because multiple transmitters  26  are being programmed with multiple vehicles  10 , several transmitters must be programmed at different times. 
         [0021]    Currently, once a secret key is re-programmed in a vehicle controller  22 , any transmitter  26  that does not include that secret key will not be recognized by the vehicle controller  22 . This creates the problem in that none of the transmitters  26  would be accepted and reprogrammable once the old secret key has been replaced by a current secret key code. Accordingly, the example system includes a method in which secret key codes are stored in a vehicle controller  22  such that secret key codes from transmitters  26  that have not yet been updated can be recognized for reprogramming purposes. 
         [0022]    Each of the vehicles  10  includes the vehicle controller  22  includes a memory location  62  that stores several secret key codes. The initial state includes a default secret key code indicated at  70 . This default secret code  70  is as the system originates from the factory and is reprogrammed with a current secret code  72 . The current secret code  72  is that code that is utilized for decrypting transmissions  42  received from the transmitter  26 . The memory location also includes a memory space  68  for an old secret code. The old secret code is the last secret code that was programmed into the vehicle controller  22  and is utilized to recognize transmitters  26  that have not yet been reprogrammed to the current secret code. 
         [0023]    The example method includes the initial step, indicated at  82  in  FIG. 4 , of replacing a default secret key code  70  with a first secret key code indicated at  72 . This first secret key code  72  is stored within the current memory location  66  within the memory device  62  of the vehicle controller  22  as indicated at  84  and shown as step  1  in  FIG. 3 . Each of the corresponding transmitters  66  is also programmable from the controller  22  to include the first secret code  72 . Programming of the vehicle controller  22  is provided by a programming module  60 . The programming module  60  is shown schematically and may be facilitated by a hand held device or software generated and run on a portable computer or other device that is capable of communicating with the vehicle controller  22  in a secure manner. 
         [0024]    Normal operation is established once the initial program complete and storage of the secret code concluded in both the vehicle controller  22 , and each of the plurality of transmitters  26 . Normal operation includes the transmission of an encrypted code that is encrypted utilizing the secret key code. This transmission from a transmitter  26  is accompanied by non-encrypted data except for the secret key. Upon receipt of this data by the vehicle controller  22 , the encrypted data is decrypted utilizing the stored key code. The decrypted data is then compared to the non-encrypted data to assure validity and authorization of the transmission to operate the various functions of vehicle  10 . 
         [0025]    When it is desired to reprogram the secret key to replace or ensure certain security needs, the first secret code value  72  is saved in the old memory storage area  68  as indicated at  86 . A second secret key code  74  is then stored in the current memory locations  66 . The default code  70  remains within the default memory location are not utilized for decryption. The storage of the second secret code  74  and the current memory location  66  is accomplished through programming module  60 . The vehicle controller  62  is then utilized to program corresponding transmitters  26  that are in that location. This corresponding programming of the vehicle controllers  22  and corresponding transmitters  26  occurs by communicating commands from the vehicle control  22  to authorize transmitters  26  that previously include recognized codes. 
         [0026]    Transmitters that were not programmed during the first cycle will still include the first secret key code  72 . Because the vehicle controller  22  remains and still is the first secret key code  72  in the old memory storage area  68  the vehicle controller will be able recognize all transmitters  26  that include transmissions that have been encrypted utilizing the first secret key code  72  or the second secret key code  74  because the first secret key code  72  is stored in old memory storage location  66 . 
         [0027]    Because the vehicle controller  22  includes the first secret key code  72 , transmitters  26  that transmit encrypted data utilizing the old secret will be capable of being reprogramming with the second secret key code  74 . The secret key code that is stored in the current memory location  66  is utilized for encryption and decryption for operation of a vehicle. 
         [0028]    A third key code  76  can be stored in the current memory location slot  66  and the second key code  74  can be moved to the old memory location slot  68  as is indicated at  88  in  FIG. 4 . Each update of the secret key increments the secret code key that was current to the old memory location  68  so that it may still communicate and allow reprogramming of transmitters  26  including the old secret key while also allowing updating of the secret key code as is desired. 
         [0029]    Reprogramming operations are allowed for transmitters that include secret keys that are stored either in the current memory location  66  or the old memory location  68  as indicated at  90  in  FIG. 4 . However, because only encryption and decryption is performed utilizing key codes sorting the current memory location  66 , those transmissions that are received utilizing old key codes are not authorized to actuate functions of the vehicle until reprogrammed. 
         [0030]    Referring to  FIG. 4 , subsequent reprogramming with a third secret key code  76  will cause the second secret key  74  to be incremented and stored in the old memory slot  68  such that transmitters  26  that include the third secret key code  76  or the second secret key code  74  will be recognized and capable of reprogramming and therefore operation of the vehicle  10 . The secret key code that was preciously stored in the old memory location  68  is overwritten and is no longer available for recognition of transmitters including the overwritten secret key code. 
         [0031]    The example method and system includes features for operating and programming a keyless entry and immobilizer system for fleet applications to provide desired security and updating capabilities. 
         [0032]    Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.