Abstract:
An electronic key system for a vehicle that prevents private information from being available to a third person. The electronic key system includes a terminal, electronic keys, and a device having comparing and control components. Each electronic key stores a distinct identification code and transmits the identification code to the vehicle. At least one of the identification codes is a restriction code for restricting the usage of the terminal. The comparing component is arranged in the vehicle and stores verification codes associated with the identification codes. The comparing component retrieves the identification code of one of the electronic keys and compares the retrieved identification code with an associated one of the verification codes. The control component restricts activation of the terminal when the retrieved identification code is the restriction code.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an electronic key system that performs a predetermined operation in a vehicle through wireless communication between an electronic key and the vehicle. 
     In recent years, intelligent transport systems (ITS), which employ information technology, have been introduced to decrease traffic jams, exhaust gas, and automobile accidents. Examples of ITS are an advanced cruise-assist highway system (AHS), which maintains an appropriate distance between vehicles and issues a warning to the driver when necessary, and electronic toll collection (ETC), which enables payment of tolls for toll roads without stopping at toll booths. Other examples of ITS are a vehicle information and communication system (VICS), which uses a terminal installed in a vehicle such as a car navigation system terminal to provide the driver with traffic information, and an advanced safety vehicle (ASV), which automatically drives a vehicle. 
     To use the ITS, various types of terminals must be installed in a vehicle. Examples of such terminals are a car navigation system terminal, an ETC terminal, and a distress call system terminal. The car navigation system is a system for navigating the driver to a designated destination and includes functions such as illustration of route to destination and registration, viewing, editing, and customizing of private information. 
     An ETC terminal performs communication through an antenna provided in a toll booth of a toll road. If an accident occurs or a passenger suddenly becomes sick when an automobile is being driven, the distress call system terminal sends the information required for rescue crews to an appropriate facility, such as a rescue center. When activated, the ETC terminal and the distress call system terminal indicate their usage history. 
     Presently, when a car owner lends the key to a third person, the third person would be able to use a vehicle terminal. For example, the third person would be able to use the navigation system terminal, the ETC terminal, or the distress call system terminal. Thus, the third person may use the navigation system terminal without consent and register, view, edit, or customize the private information stored in the vehicle terminal. Further, the third person may use the ETC terminal or the distress call system terminal without consent and look into the usage history. Therefore, it is difficult for a car owner to lend the key to a third person without having to worry about how the key will be used when, for example, having someone park or repair the car. 
     SUMMARY OF THE INVENTION 
     One aspect of the present invention is an electronic key system for use in a vehicle. The key system includes a terminal installed in the vehicle to process predetermined information and a plurality of electronic keys, each storing an identification code and transmitting the identification code to the vehicle. At least one of the identification codes is a restriction code for restricting the usage of the terminal. A comparing means is arranged in the vehicle and stores a plurality of verification codes associated with the identification codes. The comparing means retrieves the identification code of one of the electronic keys and compares the retrieved identification code with an associated one of the verification codes. A control means restricts activation of the terminal when the retrieved identification code is the restriction code. 
     Another aspect of the present invention is an electronic key system for use in a vehicle. The key system includes a terminal installed in the vehicle to store information including private information and a plurality of electronic keys, each storing an identification code and transmitting the identification code to the vehicle. At least one of the identification codes is a restriction code for restricting the usage of the terminal. A comparing means is arranged in the vehicle and stores a plurality of verification codes associated with the identification codes. The comparing means retrieves the identification code of one of the electronic keys and compares the retrieved identification code with an associated one of the verification codes. A control means for restricting activation of the terminal to prevent the private information from being accessed by a third person when the retrieved identification code is the restriction code. 
     A further aspect of the present invention is a method for controlling operation of a vehicle having information processing systems, and restricting access to private information stored in the information processing systems. The method includes providing a plurality of keys for operating the vehicle, with each key storing an identification code and at least one of the identification codes being different than any of the other identification codes. The method further includes storing verification codes in the vehicle corresponding to the identification codes, transmitting the identification code from one of the keys to the vehicle, and determining if the identification code received from the key corresponds to any of the verification codes. If the identification code received corresponds to a verification code, access to private information stored in information processing systems in the vehicle is allowed in accordance with predetermined restriction information associated with the corresponding verification code. If the identification code received does not correspond to any of the verification codes, operation of the vehicle is prevented. 
     Other aspects and advantages of the present invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which: 
         FIG. 1  is schematic block diagram illustrating an electronic key system according to a preferred embodiment of the present invention; 
         FIG. 2  is a diagram schematically illustrating the electronic key system of  FIG. 1 ; and 
         FIG. 3  is a perspective view showing the electronic key. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the drawings, like numerals are used for like elements throughout. 
       FIG. 2  is a diagram schematically illustrating an electronic key system  1  according to a preferred embodiment of the present invention. The electronic key system  1 , which is a wireless system for performing predetermined key operations, and includes an electronic key  2 , which can be carried by a person, and a controller  4 , which is installed in a vehicle  3 . Wireless communication is performed between the electronic key  2  and the controller  4 . The controller  4  and the electronic key  2  transfer various types of signals (radio transmissions) between each other via a plurality of antennas, which are installed in the vehicle. 
     The antennas includes coil antennas  5 , which are installed in left and right doors  9 , a coil antenna installed in the driver&#39;s seat, a receiving antenna  7 , and an immobilizer coil antenna  8 . Wireless communication with the electronic key  2  is enabled within range E 1  by the antenna  5 , range E 2  by the antenna  6 , and range E 3  by the antenna  8 . The antennas  5  to  8  are connected to the controller  4  by signal wires (communication cables). 
       FIG. 3  is a perspective view showing the electronic key  2 . The electronic key  2  includes a master key  10  and a plurality of (three in the preferred embodiment) sub-keys  11 ,  12 , and  13 . The master key  10  is the key that is always held by the owner (driver) of the vehicle  3 . The sub-keys  11  to  13  are the keys that may be lent to a third person. The keys  10  to  13  respectively have key plates  10   a  to  13   a  with predetermined key grooves. The key plates  10   a  to  13   a  are inserted in a door lock cylinder or an engine starting cylinder (neither shown) and turned to lock or unlock the door  9  or to mechanically start the engine. 
       FIG. 1  is schematic block diagram illustrating the electronic key system. The electronic key system  1  includes a smart key system  14 . The smart key system  14  automatically unlocks the doors  9  when the owner, who is holding the master key  10  approaches the door  9  of the vehicle  3  and automatically locks the doors  9  when the owner moves away from the vehicle  3 . Accordingly, the smart key system  14  has a keyless entry function. The smart key system  14  also has an ignition function that starts the engine by turning an ignition knob (not shown) even if the master key  10  is not inserted in the engine starting cylinder. 
     The master key  10  incorporates a microcomputer  15 , a receiving circuit  16 , and a transmitting circuit  17 . The receiving circuit  16  receives a request signal (radio transmission) sent from the vehicle  3  via an antenna  18  and provides the microcomputer  15  with the request signal. When receiving the request signal, the microcomputer  15  generates an identification (ID) code signal, which corresponds to an ID code of the master key  10  (hereinafter referred to as master ID code), and provides the transmitting circuit  17  with the ID code signal. The transmitting circuit  17  modulates the ID code signal to generate a modulated ID code signal (radio transmission) Sa. The ID code signal Sa is sent to the controller  4  via an antenna  19 . 
     The controller  4  includes a smart electronic control unit (ECU)  20 , which serves as a comparing means and a control means, a transmitting circuit  21 , and a receiving circuit  22 . The transmitting circuit  21  cause a request signal, which is provided from the smart ECU  20 , to be included in a radio transmission having a predetermined frequency and transmits the request signal to an external device via the antennas  5  or  6 . The receiving circuit  22  receives the ID code signal Sa via the antenna  7 , converts the ID code signal Sa to a pulse signal, and provides the pulse signal to the smart ECU  20 . 
     The smart ECU  20  includes a central processing unit (not shown) and a memory  20   a , which stores a plurality of ID codes (hereinafter referred to as smart ID codes; verification codes). Each smart ID code corresponds to one of the master and sub-keys  10  to  13 . Further, in accordance with the ID code signal Sa, the smart ECU  20  activates a door lock drive device  23 , a steering lock drive device  24 , and an engine controller  25 , which are installed in the vehicle  3 . 
     A signal switch  26  is connected to the smart ECU  20  to perform switching between the antennas  5  and  6  of the transmitting circuit  21 . The signal switch  26  provides the smart ECU  20  with an OFF signal before the driver enters the vehicle  3  and an ON signal when the driver gets into the vehicle  3  and closes the door  9 . When receiving the OFF signal from the signal switch  26 , the smart ECU  20  transmits a request signal from the antenna  5 . When receiving the ON signal from the signal switch  26 , the smart ECU  20  transmits a request signal from the antenna  6 . 
     The smart key system  14  functions as described below. First, when the door  9  is locked, the signal switch  26  generates the OFF signal. The smart ECU  20  intermittently transmits the request signal from the antenna  5  in accordance with the OFF signal. When the driver holding the master key  10  enters range E 1  (refer to  FIG. 2 ), the master key  10  receives the request signal via the antenna  18  and activates the microcomputer  15  to transmit the ID code signal Sa from the antenna  19 . In other words, the master key  10  is normally in a standby mode and automatically returns the ID code signal Sa when receiving the request signal. 
     The smart ECU  20  receives the ID code signal (master ID code) Sa via the antenna  7  and the receiving circuit  22  and compares the master ID code with the smart ID code. When the master ID code matches the smart ID code and the OFF signal is received from the signal switch  26 , the smart ECU  20  activates the door lock drive device  23  and unlocks the doors  9 . If the two ID codes do not match, the smart ECU  20  leaves the doors  9  in a locked state. Accordingly, the smart entry key function automatically unlocks the doors  9  without operating a key. 
     Then, when the driver is seated on the driver&#39;s seat and closes the door  9 , the signal switch  26  generates the ON signal. In accordance with the ON signal, the smart ECU  20  intermittently transmits the request signal from the antenna  6  instead of the antenna  5 . The master key  10  receives the request signal from the antenna  18  in range E 2  (refer to  FIG. 2 ) and activates the microcomputer  15  to transmit the ID code Sa from the antenna  18 . The smart ECU  20  receives the ID code signal Sa and compares the master ID code with the smart ID code. 
     When the master ID code matches the smart ID code and the ON signal is received from the signal switch  26 , the smart ECU  20  enables starting of the engine. That is, the smart ECU  20  drives the steering lock drive device  24  to unlock the steering lock (not shown) and provides the engine controller  25  with an engine starting permission signal. When the ignition knob is turned, the engine controller  25  performs fuel injection and engine ignition in accordance with the engine start permission signal to start the engine. Thus, the driver holding the master key  10  starts the engine with the ignition function just by turning the ignition knob (not shown). 
     When the two ID codes do not match, the smart ECU  20  activates its immobilizer function and prohibits engine starting. That is, the smart ECU  20  does not provide the engine controller  25  with the engine start permission signal so that fuel injection (or engine ignition) is not performed even when the ignition knob is turned to disable the starting of the engine. Thus, since the ignition function is not activated unless the master ID code matches the smart ID code, a third person who does not have the master key  10  cannot start the engine without consent. 
     A battery (not shown) drives the microcomputer  15  of the master key  10 . Just in case the battery goes dead, the electronic key system  1  employs the immobilizer system  27 . The master key  10  includes a transponder  28 , which is configured by a single IC chip. The transponder  28  includes a coil antenna  29 , a power circuit  30 , and a transponder control circuit  31 . 
     In range E 3  (refer to  FIG. 2 ), the antenna  29  receives a drive radio transmission (electromagnetic energy) from the vehicle  3 . The power circuit  30  generates power with the drive radio transmission and supplies the transponder control circuit  31  with power. The transponder control circuit  31  includes a memory  32 . The memory  32  stores a transponder ID code. The transponder control circuit  31  uses the power circuit  30  as a power supply and generates a transponder signal in accordance with the transponder ID code. The transponder control circuit  31  converts the transponder signal to a radio transmission having a predetermined frequency to generate a transponder signal (radio transmission) Sb and transmits the transponder signal Sb to an external device via the antenna  29 . 
     The controller  4  includes an immobilizer ECU  33 , which functions as a comparing means and a control means, a transponder transmitting/receiving circuit  34 , and an amplification circuit  35 . The transponder transmitting/receiving circuit  34  receives the transponder signal Sb from an external device via the antenna  8  and converts the transponder signal Sb to a pulse signal. The amplification circuit  35  amplifies the amplification circuit  35  and provides the amplified pulse signal to the immobilizer ECU  33 . 
     The immobilizer ECU  33  includes a central processing unit (not shown) and a memory  33   a , which stores a plurality of ID codes (hereinafter referred to as immobilizer ID codes; verification codes). When receiving the transponder signal (transponder ID code) Sb via the antenna  8 , the immobilizer ECU  33  compares the transponder ID code with the immobilizer ID code. When the two ID codes match, the immobilizer ECU  33  generates an encrypted engine start permission signal and provides the engine controller  25  with the encrypted engine start permission signal. 
     When the battery of the master key  10  goes dead, the immobilizer system  27  functions in the following manner. When the driver is seated on the driver&#39;s seat, the driver inserts the key plate  10   a  of the master key  10  into the engine starting cylinder. In this state, the master key  10  is located within range E 3  (refer to  FIG. 2 ). Thus, the transponder  28  receives the intermittently transmitted radio transmissions via the antenna  29  and generates power from the radio transmissions to activate the transponder control circuit  31 . The transponder control circuit  31  then transmits the transponder signal Sb from the antenna  29 . 
     The immobilizer ECU  33  receives the transponder ID code via the antenna  8 , the transponder transmitting/receiving circuit  34 , and the amplification circuit  35  and compares the transponder ID code with the immobilizer ID code. When the two ID codes do not match, the immobilizer ECU  33  does not provide the engine controller  25  with the engine start permission signal. Thus, the engine controller  25  stops engine ignition or forcibly cuts fuel injection even when the ignition knob or key is operated to prevent the engine from being started. Accordingly, this effectively prevents the vehicle from being stolen. 
     When the two ID codes match, the immobilizer ECU  33  permits engine starting and provides the engine controller  25  with the engine start permission signal. Whenever the ignition knob or key is operated, the engine controller  25  performs engine ignition to start the engine in accordance with the engine start permission signal. When the master key  10  is inserted in the engine starting cylinder, which is located beside the steering wheel, the steering lock drive device  24  is unlocked if the key groove of the master key  10  is aligned with that of the cylinder. 
     The first sub-key  11  may be used to activate the smart key system  14 . The first sub-key  11  includes a microcomputer  36 , a receiving circuit  37 , and a transmitting circuit  38 . The transmitting circuit  38  transmits the ID code signal Sc, which includes a first sub-ID code (restriction code) of the first sub-key  11 , to an external device. 
     The second and third sub-keys  12  and  13  may be used to start the engine. The second sub-key  12  includes a transponder  41 . The transponder  41  generates a transponder signal Sd, which includes a second sub-ID code (restriction code) of the second sub-key  12 , and transmits the transponder signal Sd to an external device. The third sub-key  13  includes a transponder  42 . The transponder  42  generates a transponder signal Se, which includes a third sub-ID code (restriction code) of the third sub-key  13 , and transmits the transponder signal Se to an external device. 
     A plurality of terminals, such as a car navigation system terminal  43 , an ETC terminal  44 , and a distress call system terminal  45 , are installed in the vehicle  3 . The terminals  43  to  45  are connected to the smart ECU  20  and the immobilizer ECU  33  via a vehicle LAN  46 . 
     When an ID code received from an external device is compared with an ID code stored in the memory  20   a , the smart ECU  20  generates access right information and provides the terminals  43  to  45  with the access right information via the LAN  46 . In the preferred embodiment, the smart ECU  20  generates access right information X, which permits usage of all of the terminals  43  to  45 , when receiving the master ID code from the master key  10 . The smart ECU  20  generates access right information Y, which prohibits usage of all of the terminals  43  to  45 , when receiving the first sub-ID code from the first sub-key  11 . 
     When comparing the transponder ID code with the immobilizer ID code, the immobilizer ECU  33  generates access right information and provides the access right information to the terminals  43  to  45  via the LAN  46 . In the preferred embodiment, the immobilizer ECU  33  generates the access right information Y, which prohibits usage of all of the terminals  43  to  45  when receiving the second sub-ID code from the second sub-key  12 . Further, the immobilizer ECU  33  generates the access right information Z, which permits usage of only the car navigation system terminal  43  when receiving the third sub-ID code from the third sub-key  13 . 
     The usage of the terminals  43  to  45  is enabled when the access right information X is received. Further, the usage of the terminals  43  to  45  is disabled when the access right information Y is received. A disabled state refers, for example, to a state in which the terminals  43  to  45  are not supplied with power, a state in which the terminals  43  to  45  are not activated even if their power buttons are pushed, and a state in which only an initial screen (e.g., standby screen) is continuously shown on a display of the terminals and other screens do not appear on the display. When the access right information Z is received, only the car navigation system terminal  43  is activated and the usage of the ETC terminal  44  and the distress call system terminal  45  is prohibited. 
     The generation of the access right information by the smart ECU  20  and the immobilizer ECU  33  will now be discussed. When performing key operations with the master key  10 , if the driver who is holding the master key  10  enters range E1 (refer to  FIG. 2 ), the smart ECU  20  receives the master ID code from the master key  10  and unlocks the door. Further, the smart ECU  20  provides the LAN  54  with the access right information X. In this state, the access right information X enables the terminals  43  to  45  to be activated and used normally. Accordingly, the master key  10  enables usage of all of the terminals  43  to  45 . 
     When performing key operations with the first sub-key  11 , if the driver who is holding the first sub-key  11  enters range E1 (refer to  FIG. 2 ), the smart ECU  20  receives the first sub-ID code from the first sub-key  11  and unlocks the door. Further, the smart ECU  20  provides the LAN  54  with the access right information Y. In this state, the access right information Y prohibits the usage of the terminals  43  to  45 . Accordingly, when lending the first sub-key  11  and the vehicle  3  to a third person, the third person is permitted to use the smart key system  14  but cannot use the terminals  43  to  45 . 
     When performing key operations with the second sub-key  12 , if the second sub-key  12  is inserted in an engine starting cylinder, the immobilizer ECU  33  receives the second sub-ID code from the second sub-key  12 , permits the starting of the engine, and provides the LAN  54  with the access right information Y. In this state, the access right information Y prohibits the usage of the terminals  43  to  45 . Accordingly, when lending the second sub-key  12  and the vehicle  3  to a third person, the third person is permitted to start the engine but cannot use the terminals  43  to  45 . 
     When performing key operations with the third sub-key  13 , if the third sub-key  13  is inserted in an engine starting cylinder, the immobilizer ECU  33  receives the third sub-ID code from the third sub-key  13 , permits starting of the engine, and provides the LAN  54  with the access right information Z. In this state, the access right information Z enables the usage of the car navigation system terminal  43  and disables the usage of the ETC terminal  44  and the distress call system terminal  45 . Accordingly, when lending the third sub-key  13  and the vehicle  3  to a third person, the third person is permitted to start the engine and use the car navigation system terminal  43  but cannot use the ETC terminal  44  and the distress call system terminal  45 . 
     The electronic key system  1  has the advantages described below. 
     (1) When using the first to third sub-keys  11  to  13 , the smart ECU  20  or the immobilizer ECU  33  restricts the usage of the terminals  43  to  45  in accordance with the first to third sub-keys  11  to  13 . Thus, by lending one of the first to third sub-keys  11  to  13  with the vehicle  3  to a third person, the terminals  43  to  45  cannot be used without consent. Accordingly, the key may be lent to a third person without any worries. 
     (2) When using the third sub-key  13 , only the car navigation system terminal  43  is activated and the ETC terminal  44  and the distress call system terminal  45  are not activated. Thus, by lending the sub-key  13 , the usage of only the car navigation system terminal  43  is permitted. Accordingly, in the electronic key system  1 , the sub-key may be used to drive the vehicle  3  and activate only predetermined ones of the terminals  43  to  45 . 
     (3) The first to third sub-keys  11  to  13  restrict the activation of the terminals  43  to  45 . Thus, when lending the first to third sub-keys  11  to  13  to a third person, the third person cannot activate the terminals  43  to  45 . 
     (4) The first to third sub-keys  11  to  13  restrict the usage of the ETC terminal  44 . Thus, by lending one of the first to third sub-keys  11  to  13  to a third person, the ETC terminal  44  cannot be used to pay tolls for toll roads. 
     It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, it should be understood that the present invention may be embodied in the following forms. 
     The terminals of which usage is restricted by the first to third sub-keys  11  to  13  may be altered as required. For example, the first sub-key  11  may restrict only the usage of the car navigation system terminal  43 , the second sub-key  12  may restrict the usage of the car navigation system terminal  43  and the ETC terminals  44 , and the third sub-key  13  may restrict the usage of the ETC terminal  44  and the distress call system  45 . 
     The key operation functions of the first to third sub-keys  11  to  13  may be provided through only one of the smart key system  14  and the immobilizer system  27 . For example, the first sub-key  11  may transmit the transponder signal to activate the immobilizer system  27 . Further, the second sub-key  12  and the third sub-key  13  may transmit ID code signals to activate the smart key system  14 . 
     The number of sub-keys is not limited to three and may be any number, such as one, two, or four. 
     The master key  10  may be separated into a portable device, which activates the smart key system  14 , and an ignition key, which incorporates the transponder  28  and activates the immobilizer system  27 . 
     The vehicle terminal may be, for example, a terminal of a system for downloading music through the Internet, or a terminal of a system for automatically paying for purchased items. 
     The method for restricting the usage of the terminals  43  to  45  with the first to third sub-keys  11  to  13  is not restricted as long as the usage of the terminals may be disabled. 
     The steering lock may be manually unlocked when the key plate of the electronic key  2  is inserted into the engine starting cylinder and turned as the key groove of the key plate becomes aligned with the groove of the cylinder. 
     Any type of electronic key may be used as long as it can transmit an ID code. For example, the electronic key may be an ID transmission device or a cellular phone. 
     The electronic key may transmit an ID code to the vehicle through, for example, the human body. In such a case, a driver who is holding an electronic key in which an ID code is stored touches the door of the vehicle to transmit the ID code to the vehicle  3  through the driver&#39;s body. 
     The vehicle may be a two wheel vehicle or an industrial vehicle. 
     The present examples and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.