Controller for electronic key system

A controller for an electronic key system including a portable device and an engine. When the ID code of the portable device cannot be authenticated, the controller instructs the driver of the necessary operations. When a transmitter circuit is transmitting a request signal but a receiver circuit does not receive a signal including an ID code matching the ID code stored in a memory, an authentication ECU authenticates a transponder code of the portable device with a stored transponder code to enable the starting of the engine. The authentication ECU displays the necessary operations for performing transponder code authentication.

BACKGROUND OF THE INVENTION

The present invention relates to an electronic key system.

Japanese Laid-Open Patent Publication No. 2001-311333 describes an electronic key system that improves the security level and convenience for an automobile. The electronic key system is provided with a smart ignition function that enables the starting of the engine when an authentic key is carried into an automobile. An automobile employing the electronic key system has a rotary switch or push button to start the engine. When the starting of the engine is enabled, the driver turns a knob of the rotary switch to a start position or pushes the push button to start the engine.

The electronic key system includes an electronic key (portable device), which is held by the driver, and an engine start controller, which is installed in the automobile. The portable device stores an ID code that is unique to the portable device. The engine start controller stores an ID code (automobile ID code) that is identical to the ID code of the portable device. The engine start controller performs bidirectional communication with the portable device. When the two ID codes match, the engine start controller enables the starting of the engine.

More specifically, when the door of the automobile is open, the engine start controller transmits a request signal in a range covering most of the passenger compartment to perform bidirectional communication with the portable device. When a driver carrying the portable device enters the passenger compartment, the portable device transmits a signal including the ID code in response to the request signal. Then, the engine start controller determines whether the ID code of the portable device matches the automobile ID code. If the two ID codes match, the engine start controller validates the smart ignition function to enable the starting of the engine.

The smart ignition function enables the engine to be started just by carrying the portable device into the automobile and operating the engine start switch. That is, there is no need to perform a burdensome key operation to start the engine. This improves convenience. In addition, the portable device, which is difficult to duplicate compared to conventional mechanical keys, is necessary to enable the starting of the engine. This improves the security level of the automobile. Further, an electronic key system provided with the smart ignition function normally includes an immobilizer function. The engine cannot be started when the immobilizer function is valid. Predetermined operations are performed with the portable device to invalidate the immobilizer function and enable the starting of the engine.

The portable device, which is used for the smart ignition function, includes a battery functioning as a power supply. Thus, if battery drainage occurs, the portable device does not transmit the signal including the ID code in response to the request signal from the engine start controller even if the driver is carrying the portable device when entering the automobile. In this case, bidirectional communication is not performed between the portable device and the engine start controller. Thus, the smart ignition function remains invalid. In such a state, the driver must invalidate the immobilizer function by performing the predetermined operations with the portable device to start the engine.

The portable device includes a transponder. The transponder stores a transponder code that is unique to the transponder, or the portable device. The engine start controller stores a transponder code (automobile transponder code) that is identical to the transponder code of the portable device. When the two transponder codes match, the engine start controller invalidates the immobilizer function and enables the starting of the engine.

More specifically, if the engine start switch is a rotary switch, the driver inserts the portable device in an electronic key insertion slot located in the knob of the rotary switch. A key detection switch detects the insertion of the portable device. As a result, the engine start controller transmits a transponder activation signal to the vicinity of the engine start switch. In response to the transponder activation signal, the portable device transmits a signal including the transponder code. The engine start controller then determines whether the transponder code of the portable device matches the automobile transponder code. When the two transponder codes match, the engine start controller invalidates the immobilizer function and enables the starting of the engine. In a state in which the starting of the engine is enabled, that is, when the portable device is inserted in the electronic key insertion slot of the engine start switch, the driver turns the knob of the engine start switch to the start position in order to start the engine.

If the engine start switch is a push switch, the driver pushes the engine start switch when the smart ignition function is invalid. This transmits the transponder activation signal in the vicinity of the engine start switch. In a state in which the transponder activation signal is being transmitted in the vicinity of the engine start switch, the driver holds the portable device near the engine start switch. As a result, in response to the transponder activation signal, the portable device transmits a signal including the transponder code. The engine start controller then invalidates the immobilizer function and enables the starting of the engine. When the starting of the engine is enabled, the driver pushes the engine start switch again to start the engine.

As described above, when the smart ignition function is valid, the starting of the engine is enabled just by carrying the portable device into the automobile. When the smart ignition function is invalid due to a reason such as battery drainage, predetermined operations must be performed to enable the starting of the engine.

However, circumstances such as battery drainage does not often occur. Thus, even if the driver is aware that predetermined operations are necessary, the driver may forget the specific operations. Thus, there is a necessity to instruct the driver of the operations that must be performed when the smart ignition function is invalid.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a controller that instructs the driver of the operations that must be performed when the smart ignition function is invalid.

One aspect of the present invention provides a controller for an electronic key system including a portable device, carried by a user, and a control subject. The portable device incorporates a transponder and generates a signal including an ID code unique to the portable device and a signal including a transponder code unique to the transponder. The controller includes a first storage circuit for storing an ID code identical to the ID code of the portable device. A first transmitter circuit transmits a request signal that causes the portable device to transmit the signal including the ID code. A first receiver circuit receives the signal including the ID code that is transmitted from the portable device in response to the request signal. A first control unit determines whether the ID code stored in the first storage circuit matches the ID code of the portable device and performs a first control that enables activation of the control subject when the two ID codes match. A second storage circuit stores a transponder code identical to the transponder code of the portable device. A second transmitter circuit transmits a transponder activation signal that causes the portable device to transmit the signal including the transponder code. A second receiver circuit receives the signal including the transponder code that is transmitted from the portable device in response to the transponder activation signal. A second control unit determines whether the transponder code stored in the second storage circuit matches the transponder code of the portable device and performs a second control that enables activation of the control subject when the two transponder codes match. An instruction device instructs the user of an operation that must be performed to have the second control unit enable activation of the control subject when the first receiver circuit does not receive the signal including the ID code from the portable device even though the first transmitter circuit is transmitting the request signal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An electronic key system for an automobile according to a preferred embodiment of the present invention will now be described.

Referring toFIG. 1, an electronic key system1includes a portable device2and an engine start controller3. The portable device2is carried by a driver. The engine start controller3is installed in an automobile. In the electronic key system1, bidirectional communication is performed between the portable device2and the engine start controller3.

The portable device2is provided with a reception function and a transmission function. The portable device2includes a receiver antenna11, a receiver circuit12, a microcomputer13, a transmitter circuit14, a transmitter antenna15, a battery16, and a transponder17. The receiver circuit12receives a request signal, which is transmitted from the engine start controller3, via the receiver antenna11. Upon receipt of the request signal from the engine start controller3, the receiver circuit12demodulates the request signal to generate a reception signal and provides the reception signal to the microcomputer13.

The microcomputer13includes a memory13ain addition to a CPU, a ROM, and a RAM (not shown). The memory13astores an ID code that is unique to the portable device2. When receiving the reception signal from the receiver circuit12, the microcomputer13provides a signal including the ID code of the portable device to the transmitter circuit14in order to respond to the request signal.

The transmitter circuit14modulates the signal including the ID code of the portable device2to a signal having a predetermined frequency (in the preferred embodiment, 300 MHz) and transmits the modulated signal from the transmitter antenna15. The battery16functions as a power supply for transmitting the signal including the ID code of the portable device2in response to the request signal. The battery16is a button cell battery (primary battery). The transponder17stores a transponder code that is unique to the transponder17, or the portable device2. In response to a transponder activation signal transmitted from the engine start controller3, the transponder17generates electromotive force to transmit a signal including the transponder code with a predetermined frequency (in the preferred embodiment, 134 KHz).

The engine start controller3includes a transmitter circuit21, a transmitter antenna22, a receiver antenna23, a receiver circuit24, a power supply circuit25, a transceiver circuit26, a transceiver antenna27, and an authentication ECU28. The transmitter circuit21(first transmitter circuit) modulates the request signal provided from the authentication ECU28to a signal having a predetermined frequency (in the preferred embodiment, 134 KHz) and transmits the modulated signal from the transmitter antenna22. The transmitter circuit21transmits the request signal to have the portable device2transmit the signal including the ID code of the portable device2.

The transmitter antenna22is configured by a bar antenna arranged underneath the driver seat. The directivity of the transmitter antenna22and the output of the request signal are set so that the request signal is transmitted throughout the entire passenger compartment but does not leak out of the passenger compartment. In the preferred embodiment, the request signal is transmitted to a first range A1, which is shown by the broken line inFIG. 2. When the request signal is transmitted from the transmitter antenna22, bidirectional communication is performed between the portable device2and the engine start controller3in the first range A1.

The receiver circuit24(first receiver circuit) receives the signal including the ID code of the portable device2, which is transmitted by the portable device2in response to the request signal, via the receiver antenna23. The receiver circuit24demodulates the signal including the ID code of the portable device2to generate a reception signal and provides the reception signal to the authentication ECU28.

The transceiver circuit26uses the transponder activation signal provided from the authentication ECU28and the power supplied from the power supply circuit25to generate a transponder activation signal having a predetermined frequency (in the preferred embodiment, 134 KHz). The transceiver circuit26then transmits the transponder activation signal from the transceiver antenna27to have the portable device transmit a signal including the transponder code. Further, the transceiver circuit26functions as a second transmitter circuit and a second receiver circuit. The power supply circuit25supplies the transceiver circuit26with the power required to generate the transponder activation signal based on a power supply command signal from the authentication ECU28.

The transceiver antenna27is a coil antenna arranged near an engine start switch60, which is located near the driver seat. The directivity of the transceiver antenna27and the output of the transponder activation signal are set so that the transponder activation signal is transmitted to a small range that is in reach from the driver when seated on the driver seat. More specifically, the transponder activation signal is transmitted in a range extending between 20 to 50 mm from the engine start switch60towards the driver seat. The transponder activation signal is transmitted in a second range A2, which is shown in an exaggerated manner by broken lines inFIG. 2. When the transponder activation signal is transmitted from the transceiver antenna27, bidirectional communication is performed between the portable device2and the engine start controller3in the second range A2.

The transceiver circuit26receives the signal including the transponder code, which is transmitted from the portable device2in response to the transponder activation signal, via the transceiver antenna27. Upon receipt of the signal including the transponder code from the portable device2, the transceiver circuit26demodulates the signal and generates a reception signal. The transceiver circuit26then provides the reception signal to the authentication ECU28.

The authentication ECU28includes a memory28ain addition to a CPU, a ROM, and a RAM. The memory28afunctions as a first storage circuit and stores an ID code (automobile ID code) that is identical to the ID code of the portable device2. The memory28aalso functions as a second storage circuit and stores a transponder code (automobile transponder code) that is identical to the transponder code of the portable device2.

To transmit the request signal in the first range A1, the authentication ECU28executes smart control and provides the request signal to the transmitter circuit21. Further, to transmit the transponder activation signal in the second range A2, the transceiver circuit26executes immobilizer control and provides the transponder activation signal to the transceiver circuit26. During the execution of the immobilizer control, the authentication ECU28provides the power supply command signal to the power supply circuit25. The smart control and the immobilizer control are executed so that the request signal transmitted from the transmitter antenna22and the transponder activation signal transmitted from the transceiver antenna27do not interfere with one another in the passenger compartment. That is, the authentication ECU28does not output the request signal simultaneously with the transponder activation signal and the power supply signal.

When executing the smart control and receiving a reception signal including the ID code of the portable device2from the receiver circuit24, the authentication ECU28determines whether or not the ID code of the portable device2matches the automobile ID code. That is, the authentication ECU28executes ID code authentication. Further, when executing the immobilizer control and receiving a reception signal including the transponder code of the portable device2from the transceiver circuit26, the authentication ECU28determines whether or not the transponder code of the portable device2matches the automobile transponder code. That is, the authentication ECU28executes transponder code authentication.

An electronic fuel injection (EFI) ECU40is electrically connected to the authentication ECU28. The authentication ECU28provides the EFI ECU40with an engine start enabling signal when the two ID codes match. In this case, the authentication ECU28functions as a first control unit executing a first control as an engine start enabling control. Further, when the two transponder codes match, the authentication ECU28provides the EFI ECU40with an engine start enabling signal. In this case, the authentication ECU28functions as a second control unit executing a second control as the engine start enabling control.

The EFI ECU40starts the engine90, which functions as a control subject. The EFI ECU40is electrically connected to a brake switch50and the engine start switch60.

The brake switch50detects operation of the brake. When a brake pedal (not shown) is depressed, the brake switch50accordingly provides the EFI ECU40with a detection signal during the period the brake pedal is depressed. The EFI ECU40determines whether the brake is being operated from the detection signal of the brake switch50.

The engine start switch60is a push switch that has a button pushed by the driver. When the button is pushed, the engine start switch60accordingly provides the EFI ECU40with a detection signal during the period the button is pushed. The EFI ECU40determines whether the engine start switch60is being operated from the detection signal of the engine start switch60.

When receiving the engine start enabling signal from the authentication ECU28, if the EFI ECU40determines that the brake and engine start switch60are both being operated, the EFI ECU40starts the engine90with a starter motor (not shown).

A door courtesy switch70is electrically connected to the authentication ECU28. When the automobile door is open, the door courtesy switch70accordingly provides the authentication ECU28with a detection signal during the period the door is open. When the door is closed, the door courtesy switch70accordingly provides the authentication ECU28with a detection signal during the period the door is closed. The authentication ECU28determines the state of the door based on the detection signal of the door courtesy switch70.

The engine start controller3includes a display80, which functions as an instruction device. The display80is electrically connected to the authentication ECU28. A display used for a so-called car navigation system is used as the display80. Information for starting the engine90is shown on the display80.

The operation for starting the engine90will now be described with reference to the flowcharts ofFIGS. 3 to 5.

Based on the detection signal of the door courtesy switch70, when the authentication ECU28determines that the door is open (YES in S1), the authentication ECU28executes the smart control (S2). That is, when the door is open, the authentication ECU28provides the transmitter circuit21with the request signal to validate the smart ignition function. Then, the transmitter circuit21transmits the request signal from the transmitter antenna22to the first range A1, which covers the entire passenger compartment. As a result, bidirectional communication between the portable device2and the engine start controller3is enabled in the first range A1.

When the driver, who is carrying the portable device2, enters the passenger compartment, or the first range A1, the portable device2transmits a signal including the ID code in response to the request signal. When receiving the signal via the receiver antenna23, the receiver circuit24provides the authentication ECU28with a reception signal.

Then, the authentication ECU28performs ID code authentication (S3). More specifically, the authentication ECU28determines whether the ID code of the portable device2that is included in the reception signal from the receiver circuit24matches the automobile ID code stored in the memory28a. When the two ID codes match (YES in S3), the authentication ECU28executes the first control (S4). More specifically, the authentication ECU28provides the engine start enabling signal to the EFI ECU40when the two ID codes match. If the brake and engine start switch60are both operated when the engine start enabling signal is provided from the authentication ECU28(YES in S5), the EFI ECU40starts the engine90with the starter motor (S6).

If the brake or the engine start switch60is not operated (NO in S5) even though the first control is being performed (S4), when a predetermined first period T1elapses from the initiation of the first control (YES in S7) but a predetermined second period T2has not yet elapsed (NO in S8), the authentication ECU28displays a first guide on the display80(S9). In this case, the smart ignition function is valid. However, there is a high possibility that the driver is not aware of the operation required to start the engine90. Accordingly, the authentication ECU28displays the first guide on the display80to instruct the driver (user) of the operation required to start the engine90. For example, the authentication ECU28displays the message “engine will start by pushing switch while depressing brake pedal” on the display80as the first guide.

If the first guide is displayed on the display80(S9) but the brake and engine start switch60are both not operated (NO in S5) and the second period T2elapses from when the first guide is displayed (YES in S7and YES in S8), the authentication ECU28proceeds to step S10. In step S10, the authentication ECU28stops displaying the first guide. Subsequently, the authentication ECU28disables the starting of the engine90(S11). In this case, there is a high possibility that the driver does not intend to start the engine90. Thus, the authentication ECU28stops providing the EFI ECU40with the engine start enabling signal.

If the smart control is being executed (S2) but a reception signal including the ID code that matches the automobile ID code is not provided from the receiver circuit24(NO in S3) and a predetermined time T3from initiation of the smart control elapses (YES in S21), the authentication ECU28proceeds to step S24. In this case, there is a high possibility that battery drainage has occurred in the portable device2carried by the driver who has entered the automobile. Further, there is a high possibility that the driver is not aware of the required operations when the smart ignition function is invalid due to battery drainage of the portable device2.

The authentication ECU28also proceeds to step S24if the ID code authentication is not performed in step S3but the brake is operated (YES in S22) before the third period T3from initiation of the smart control elapses (NO in S21). Further, the authentication ECU28proceeds to step S24when the ID code authentication is not performed in step S3but the engine start switch60is operated (YES in S23) before the third period T3from initiation of the smart control elapses (NO in S21). In such cases, even though the smart ignition function is invalid due to battery drainage, there is a high possibility that the driver is not aware of the battery drainage and is performing operations assuming that the smart ignition function is valid.

In step S24, the authentication ECU28stops the smart control. Then, the authentication ECU28executes the immobilizer control (S25). The authentication ECU28invalidates the immobilizer function to enable the starting of the engine90. More specifically, the authentication ECU28provides the power supply circuit25with the power supply command signal and the transceiver circuit26with the transponder activation signal. Then, the transceiver circuit26transmits the transponder activation signal to the second range A2, which covers the limited area near the engine start switch60. As a result, bidirectional communication is enabled between the portable device2and the engine start controller3in the second range A2.

Subsequently, the authentication ECU28displays the second guide on the display80(S26). More specifically, when affirmative determinations are given in any one of steps S21to S23, there is a high possibility that the driver is not aware of the operations required to start the engine90when the smart ignition function is invalid. Thus, the authentication ECU28displays the second guide on the display80to instruct the driver of the necessary operation. For example, the authentication ECU28displays the message “hold the portable device near the switch” on the display80as the second guide.

In this state, when the driver holds the portable device2in the second range A2near the engine start switch60, the portable device2transmits a signal including the transponder code in response to the transponder activation signal. The signal is then provided to the transceiver circuit26via the transceiver antenna27. As a result, the transceiver circuit26provides the authentication ECU28with a reception signal.

The authentication ECU28then executes the transponder code authentication (S27). More specifically, the authentication ECU28determines whether the transponder code of the portable device included in the reception signal from the transceiver circuit26matches the automobile transponder code stored in the memory28a. When determining that the two transponder codes match (YES in S27), the authentication ECU28stops displaying the second guide (S28). Then, the authentication ECU28executes the second control (S29). More specifically, when the two transponder codes match, the authentication ECU28provides the EFI ECU40with the engine start enabling signal. In a state in which the engine start enabling signal is being received from the authentication ECU28, if the brake and engine start switch60are both operated, the EFI ECU40controls the starter motor to start the engine90(S31).

If the second guide is being displayed (S26) but a reception signal including a transponder code matching the automobile transponder code is not received (NO in S27), when a predetermined fourth period T4elapses from when the second guide is displayed (YES in S32), the authentication ECU28proceeds to step S33. In step S33, the authentication ECU28stops displaying the second guide. Then, the authentication ECU28stops the immobilizer control (S34). In this case, there is a high possibility that the driver does not intend to start the engine90. Accordingly, the authentication ECU28stops providing the power supply circuit25with the power supply command signal and stops providing the transceiver circuit26with the transponder activation signal.

If the brake or engine start switch60is not operated (NO in S30) even though the second control is being executed (S29), when a predetermined fifth period T5elapses from the initiation of the second control but a predetermined sixth period T6has not yet elapsed (NO in S42), the authentication ECU28displays a third guide on the display80(S43). In this case, there is a high possibility that the driver is not aware of the operations for invalidating the immobilizer function and starting the engine90. Accordingly, the authentication ECU28displays the third guide on the display80to instruct the driver of the operation required to start the engine90. For example, the authentication ECU28displays a message “engine will start by pushing switch while depressing brake pedal” on the display80as the third guide.

If the third guide is displayed on the display80(S43) but the brake and engine start switch60are both not operated (NO in S30) and the sixth period T2elapses from when the third guide is displayed (YES in S41and YES in S42), the authentication ECU28proceeds to step S44. In step S44, the authentication ECU28stops displaying the third guide. Subsequently, the authentication ECU28disables the starting of the engine90(S45). In this case, there is a high possibility that the driver does not intend to start the engine90. Thus, the authentication ECU28stops providing the EFI ECU40with the engine start enabling signal.

The preferred embodiment has the advantages described below.

(1) When the transmitter circuit21is transmitting the request signal but the receiver circuit24does not receive a signal including an ID code matching the ID code stored in the memory28a, the authentication ECU28displays the procedure for starting the engine90(S26) through execution of the second control (transponder code authentication). More specifically, when bidirectional communication cannot be performed between the portable device2and the engine start controller3in the first range A1, the authentication ECU28cannot enable the starting of the engine90through the first control (ID code authentication). Thus, the authentication ECU28displays the operation that is necessary in this state on the display80. This enables the driver to perform the operation that is necessary when bidirectional communication is not performed between the portable device2and the engine start controller3in the first range A1.

(2) When the smart ignition function is invalid due to battery drainage in the portable device2, the authentication ECU28instructs the user of the operation that invalidates the immobilizer function and starts the engine90, or displays the second guide on the display80. Thus, even if the driver forgets such operation, the driver will hold the portable device2near the engine start switch60without any confusion by looking at the message on the display80. This ensures that the driver will be able to perform the operation for invalidating the immobilizer function that would be unnecessary if the smart ignition function were valid.

(3) If the receiver circuit24does not receive a signal including an ID code matching the ID code stored in the memory28aeven though the transmitter circuit21is transmitting the request signal and the third period T3from when transmission of the request signal is initiated elapses, the display80displays the second guide to instruct the driver of the operation necessary for enabling the starting of the engine90. Accordingly, the display80displays the message at an appropriate timing. That is, the second guide is displayed only when necessary. This reduces the power consumed to display the second guide.

(4) When the driver performs operations assuming that the starting of the engine90has been enabled through the first control (ID code authentication) even though the authentication ECU28has not enabled the starting of the engine90, the display80displays the instruction for having the driver perform the operation necessary to enable the starting of the engine90. In this case, the possibility of the driver being aware that bidirectional communication between the portable device2and the engine start controller3in the first range A1is low. Further, there is a high possibility that the driver does not know the operation required to enable the starting of the engine. Thus, the display80displays a message, at an appropriate timing, for instructing the driver of the operation required to enable the starting of the engine90. The message enables the driver to perform the required operation when bidirectional communication between the portable device2and the engine start controller3is not performed in the first range A1.

(5) Battery drainage of the portable device2seldom occurs. Thus, even if battery drainage occurs in the portable device2, the driver tries to start the engine90as if he or she usually does assuming that battery drainage has not occurred and that the smart ignition function is valid. More specifically, there is a high possibility of the driver operating the brake and engine start switch60even though the smart ignition function is invalid due to battery drainage. Thus, in the preferred embodiment, if the brake or engine start switch60are operated even though the smart ignition function is invalid, the authentication ECU28determines that such operation has been performed since the driver is not aware of the battery drainage. Accordingly, the driver displays the second guide on the display80. As a result, the driver becomes aware of the battery drainage in the portable device by looking at the display and is informed that the portable device2should be held near the engine start switch60.

(6) The display80displays the second guide during the period in which the transceiver circuit26transmits the transponder activation signal. That is, when bidirectional communication is not performed between the portable device2and the engine start controller3in the first range A1, the display80displays the second guide during the period in which the driver can perform the operation required to enable engine starting. Thus, the second guide is not displayed when unnecessary. This reduces the power consumed to display the second guide.

(7) The display80stops displaying the second guide when a predetermined time elapses (fourth period T4) measured from when the second guide is displayed. Thus, the display80does not continuously display the second guide in an unnecessary manner. This reduces the power consumed to display the second guide.

(8) In addition to the second guide, the display80displays the first guide and the third guide. Thus, if the driver is not accustomed to driving an automobile provided with a one-push type smart ignition function, the driver can start the engine90without any confusion by following the guide.

(9) The display80stops displaying the first guide when a predetermined time (second period T2) elapses from when the first guide is displayed. Further, the display80stops displaying the third guide when a predetermined time (sixth period T6) elapses from when the third guide is displayed. This reduces the power consumed to display the guides.

The display80may display the message “depress the brake and push the switch while holding the portable device near the switch” as the second guide.

The display80may display the message “refer to page X of manual” as the second guide.

The display80may display the message “refer to caution label on rear side of sun visor” as the second guide.

The display80may display the message “replace battery (type: AB1234)” as the second guide.

The display80may sequentially display the procedures that become necessary when the smart ignition function is invalid such as “push menu button of car navigation system to . . . ” as the second guide.

After performing step S11ofFIG. 3, the authentication ECU28may display the message “open door to start engine” as a fourth guide on the display80. Further, the authentication ECU28may stop displaying the fourth guide if a predetermined time (seventh period T7) elapses from when the fourth guide is displayed. Alternatively, the authentication ECU28may stop displaying the fourth guide if the door is opened. As another option, after displaying the fourth guide, the authentication ECU28may stop displaying the fourth guide when a predetermined time (seventh period T7) elapses or when the door is opened, whichever occurs earlier.

After performing step S34ofFIG. 4, the authentication ECU28may display the message “open door to start engine” as a fifth guide on the display80. Further, the authentication ECU28may stop displaying the fifth guide if a predetermined time (eighth period T8) elapses from when the fifth guide is displayed. Alternatively, the authentication ECU28may stop displaying the fifth guide if the door is opened. As another option, after displaying the fifth guide, the authentication ECU28may stop displaying the fifth guide when the predetermined time (eighth period T8) elapses or when the door is opened, whichever occurs earlier.

After performing step S45ofFIG. 5, the authentication ECU28may display the message “open door to start engine” as a sixth guide on the display80. Further, the authentication ECU28may stop displaying the sixth guide if a predetermined time (ninth period T9) elapses from when the sixth guide is displayed. Alternatively, the authentication ECU28may stop displaying the sixth guide if the door is opened. As another option, after displaying the sixth guide, the authentication ECU28may stop displaying the sixth guide when the predetermined time (eighth period T9) elapses or when the door is opened, whichever occurs earlier.

In addition to or in lieu of the first to sixth guide, which are messages including words, the authentication ECU28may use symbols or pictures to display information relating to the operations for starting the engine90on the display80.

A rotary switch may be used instead of the push switch as the engine start switch60. In this case, the authentication ECU28may display the message “turn knob while depressing the brake to start engine” as the first guide. Further, in this case, the display80may display a message such as “insert portable device in knob” as the second guide. The display80may also display a message such as “depress brake and turn knob to start engine.”

The messages of the first to sixth guides may be displayed on a display arranged in an instrument panel instead of a display of a car navigation system.

In addition to or instead of displaying the information for starting the engine90, the voice function of a car navigation system may be used to generate audio instructions for instructing a driver of the operations for starting the engine.