Patent Publication Number: US-2011060481-A1

Title: Antitheft method and system for motorcycles

Description:
BACKGROUND OF THE INVENTION 
     1.Field of the Invention 
     The present invention relates to an antitheft method and system for motorcycles, and more particularly, to an antitheft method and system for motorcycles for rapidly starting a motorcycle without having a physical key and, when unauthorized power-up or engine start-up is detected, cutting off the unauthorized power-up or stopping engine start-up to prevent the motorcycle from being stolen. 
     2. Discussion of the Related Art 
     Generally, it is required to insert a key into a key cylinder, turn the key, and then press a start button or step on a kick start in order to start a motorcycle. However, this procedure is inconvenient for a user to start the motorcycle because the user must carry the key, insert the key into the key cylinder and turn the key cylinder to ‘ON’ position. 
     Motorcycles are exposed to danger of theft all the time because the motorcycles are easily accessible by people. Further, most of motorcycles have a problem that their engines can be forcibly started by operating wiring through an illegal method. For example, a motorcycle engine is started when a connector connecting a key cylinder with harnesses is separated and a kick start is hit, a wire harness is cut and the kick start is hit, or one of an ignition ground or an ignition wire is cut and the kick start is hit. 
     Recently, a smart key system which easily starts motorcycles and improves an antitheft technique has been widely applied to motorcycles. However, the smart key system can be applied to most of motorcycles only in a manufacturing step and motorcycles equipped with the smart key system become expensive due to system complexity and a large number of components. Moreover, when wiring of a motorcycle is operated through an illegal method to start the motorcycle, it is difficult to detect the start-up of the motorcycle. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an antitheft method and system for motorcycles for detecting power-up of a motorcycle or engine start-up performed through an illegal method and cutting off the power-up or engine start-up. 
     It is another object of the present invention to provide an antitheft method and system for motorcycles for generating a theft alarm signal when an unauthorized power-up or engine start-up is detected. 
     It is still another object of the present invention to provide an antitheft method and system for motorcycles for allowing a user to confirm an electronic identifier and start a motorcycle rapidly and easily without inserting a physical key into a key cylinder. 
     According to an aspect of the present invention, there is provide an antitheft method for motorcycles, which includes a step in which an electronic control unit senses power-up of a motorcycle or engine start-up before authentication; a step in which the electronic control unit transmits an electronic identifier of the electronic control unit to a smart remote controller through radio communication; and a step in which the electronic control unit cuts off the motorcycle power-up or engine start-up when the electronic control unit does not receive a response signal to the electronic identifier of the electronic control unit from the smart remote controller. 
     The electronic control unit may generate a theft alarm signal in the step of cutting off the motorcycle power-up or engine start-up. 
     The electronic control unit may ground the output of an IG control circuit to the ground to ground AC power supplied to an engine ignition controller of the motorcycle to the ground or cut off DC power supplied to the engine ignition controller so as to stop the engine start-up in the step of cutting off the motorcycle power-up or engine start-up. 
     The antitheft method for motorcycles may further include a step of determining whether the electronic identifier of the electronic control unit, received by the smart remote controller, is identical to the electronic identifier of the smart remote controller; and a step in which the smart remote controller sends no response when the electronic identifier of the electronic control unit is not identical to the electronic identifier of the smart remote controller. 
     The antitheft method for motorcycles may further include a step in which the smart remote controller transmits a response signal including the electronic identifier of the smart remote controller to the electronic control unit; and a step in which the electronic control unit determines whether the electronic identifier of the smart remote controller, which is included in the response signal, is identical to the electronic identifier of the electronic control unit and, when the electronic identifier of the smart remote controller is identical to the electronic identifier of the electronic control unit, prepares or maintains engine start-up if the electronic identifier of the smart remote controller is identical to the electronic identifier of the electronic control unit. 
     The antitheft method for motorcycles may further include a step in which the electronic control unit maintains a predetermined handle lock state when the electronic identifier of the smart remote controller is not identical to the electronic identifier of the electronic control unit; and a step in which the electronic control unit cancels the predetermined handle lock state when the electronic identifier of the smart remote controller is identical to the electronic identifier of the electronic control unit. 
     In the step of transmitting the electronic identifier of the electronic control unit to the smart remote controller, the electronic control unit may transmit the electronic identifier of the electronic control unit to the smart remote controller through radio communication when a pressure sensing signal is received from a pressure sensor attached to a seat of the motorcycle or a braking operation is sensed. 
     According to another aspect of the present invention, there is provided an antitheft method for motorcycles, which includes a step in which an electronic control unit senses power-up of a motorcycle or engine start-up before authentication; a step in which the electronic control unit requests a smart remote controller to transmit an electronic identifier of the smart remote controller through radio communication; and a step in which the electronic control unit cuts off the motorcycle power-up or engine start-up when the electronic control unit does not receive the electronic identifier of the smart remote controller within a predetermined period of time. 
     The antitheft method for motorcycles may further include a step in which the electronic control unit receives the electronic identifier of the smart remote controller from the smart remote controller; a step in which the electronic control unit determines whether the electronic identifier of the smart remote controller is identical to the electronic identifier of the electronic control unit; and a step in which the electronic control unit performs the step of cutting off the motorcycle power-up or engine start-up when the electronic identifier of the smart remote controller is not identical to the electronic identifier of the electronic control unit and prepares or maintains engine start-up when the electronic identifier of the smart remote controller is identical to the electronic identifier of the electronic control unit. 
     The electronic control unit may not start the engine of the motorcycle if a start button is pressed within the predetermined period of time for which the electronic control unit does not receive the response signal or the electronic identifier of the smart remote controller in the step of cutting off the motorcycle power-up or engine start-up. 
     In the step of requesting the smart remote controller to transmit the electronic identifier of the smart remote controller, the electronic control unit may request the smart remote controller to transmit the electronic identifier of the smart remote controller through radio communication when a pressure sensing signal is received from a pressure sensor attached to a seat of the motorcycle or a braking operation is sensed. 
     The electronic control unit may sense tilting of the motorcycle to the left or right at greater than a predetermined angle or lifting of the front or rear wheel of the motorcycle at greater than a predetermined angle in the step of sensing the power-up or engine start-up before authentication, and the electronic control unit may generate a theft alarm signal in the step of cutting off the power-up or engine start-up. 
     The electronic control unit may transmit the theft alarm signal to an authenticated smart remote controller to raise a theft alarm. 
     According to another aspect of the present invention, there is provided an antitheft system for motorcycles, which includes an electronic control unit and a smart remote controller. The electronic control unit senses motorcycle power-up or engine start-up before authentication and transmits/receives an electronic identifier. The smart remote controller receives an electronic identifier from the electronic control unit, transmits a response signal and determines whether the received electronic identifier of the electronic control unit is identical to an electronic identifier of the smart remote controller. The electronic control unit transmits the electronic identifier of the electronic control unit to the smart remote controller when sensing motorcycle power-up or engine start-up. The smart remote controller receives the electronic identifier of the electronic control unit, determines whether the received electronic identifier of the electronic control unit is identical to the electronic identifier of the smart remote controller, sends no response if the received electronic identifier of the electronic control unit is not identical to the electronic identifier of the smart remote controller, and transmits the response signal including the electronic identifier of the smart remote controller to the electronic control unit if the received electronic identifier of the electronic control unit is identical to the electronic identifier of the smart remote controller. The electronic control unit cuts off motorcycle power-up or engine start-up if the response signal is not received within a predetermined time, determines whether the electronic identifier of the smart remote controller, which is included in the response signal, is identical to the electronic identifier of the electronic control unit if the response signal is received, and prepares or maintains engine start-up when the electronic identifier of the smart remote controller is identical to the electronic identifier of the electronic control unit. The electronic control unit may generate a theft alarm signal when the response signal is not received within the predetermined time. 
     The electronic control unit may include a sensing unit, a first controller and a first radio communication unit. The sensing unit senses motorcycle power-up or engine start-up. The first controller determines whether the electronic identifier of the smart remote controller is identical to the electronic identifier of the electronic control unit. The first radio communication unit transmits/receives the electronic identifiers. 
     The smart remote controller includes a second radio communication unit and a second controller. The second radio communication unit receives the electronic identifier of the electronic control unit and transmits the response signal. The second controller determines whether the electronic identifier of the smart remote controller is identical to the electronic identifier of the electronic control unit. 
     The electronic control unit may ground the output of an IG control circuit to the ground to ground AC power supplied to an engine ignition controller of the motorcycle to the ground or cut off DC power supplied to the engine ignition controller so as to stop the engine start-up in the step of cutting off the motorcycle power-up or engine start-up. 
     The electronic control unit may maintain a sleep state while the motorcycle engine is cut off. 
     The electronic control unit may check a battery voltage of the motorcycle and notify a user of a battery change time. 
     The smart remote controller may maintain a sleep state until an electronic identifier request signal is received from the electronic control unit. 
     The smart remote controller may send no response when an electronic control unit other than an authenticated electronic control unit requests the smart remote controller to transmit the electronic identifier. 
     The smart remote controller may check a battery voltage of the smart remote controller and notify a user of a battery change time. 
     The antitheft method and system for motorcycles according to the present invention can detect power-up of a motorcycle or engine start-up performed through an illegal method and cut off the power-up or engine start-up. Further, the antitheft method and system for motorcycles according to the present invention can generate a theft alarm signal when unauthenticated power-up or engine start-up is detected. Accordingly, the motorcycle can be prevented from being stolen. 
     Moreover, the antitheft method and system for motorcycles according to the present invention can confirm an electronic identifier and start the motorcycle without inserting a physical key into a key cylinder, and thus a user can start the motorcycle easily and rapidly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings: 
         FIG. 1  is a block diagram of an electronic control unit according to an embodiment of the present invention; 
         FIG. 2  is a block diagram of a smart remote controller according to an embodiment of the present invention; 
         FIG. 3  is a flowchart showing an antitheft method for motorcycles according to an embodiment of the present invention; and 
         FIG. 4  is a flowchart showing an antitheft method for motorcycles according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, the present invention will be described in detail by explaining preferred embodiments of the invention with reference to the attached drawings. Like reference numerals in the drawings denote like elements. 
     In the specification, “power connection or engine start-up before authentication” means power connection or engine start-up when authentication between an electronic control unit and a smart remote controller is not performed. 
       FIG. 1  is a block diagram of an electronic control unit  100  according to an embodiment of the present invention and  FIG. 2  is a block diagram of a smart remote controller  200  according to an embodiment of the present invention. 
     Referring to  FIG. 1 , the electronic control unit  100  according to an embodiment of the present invention includes a sensing unit  110 , a first controller  120  and a first radio communication unit  130 . When power-up or engine start-up before authentication is performed through an illegal method, the electronic control unit  100  cuts off the power-up or engine start-up. 
     The sensing unit  110  includes a power-up sensor  111 , an engine start-up sensor  112  and a sensor unit  113 . The power-up sensor  111  senses whether a motorcycle is powered up. The engine start-up sensor  112  senses whether the engine of the motorcycle is started. The sensor unit  113  includes a pressure sensor and a motion sensor. The pressure sensor senses pressure or weight applied to a seat of the motorcycle to sense whether a person sits on the seat. The motion sensor senses whether the motorcycle is tilted to the left or right at greater than a predetermined angle and whether the front or rear wheel of the motorcycle is lifted at greater than a predetermined angle. Here, the motion sensor includes at least one of an acceleration sensor, an angular velocity sensor, a terrestrial magnetism sensor and a gyro sensor. However, the present invention is not limited thereto. The sensing unit  110  notifies the first controller  120  of power-up or engine start-up before authentication when the power-up or engine start-up is sensed. Further, the sensor unit  113  transmits a sensing signal to the first controller  120 . 
     The first radio communication unit  130  includes a low frequency (LF) transmission circuit  131 , an LF antenna  132 , a radio frequency (RF) receiving circuit  133 , and an RF antenna  134 . The LF transmission circuit  131  transmits an electronic identifier of the electronic control unit  100  to a smart remote controller  200  which will be described in detail with reference to  FIG. 2  through the LF antenna  132 . In another embodiment of the invention, the LF transmission circuit  131  can transmit an electronic identifier transmission request signal to the smart remote controller  200 . The RF receiving circuit  133  receives a response signal from the smart remote controller  200  through the RF antenna  134 . 
     Although the electronic control unit  100  transmits signals through LF and receives signals through RF in the current embodiment of the invention, the present invention is not limited thereto. For example, the electronic control unit  100  can transmit and receive signals through LF, transmit and receive signals through RF, or transmit signals through RF and receive signals through LF. 
     When the first controller  120  determines that unauthenticated power-up or engine start-up is performed, an output circuit  141  can generate a theft alarm signal. The theft alarm signal can be generated by using a siren  142  or a lamp  143 . Further, even if a key cylinder is on by using a replica key or an illegal method to supply power to electronic devices of the motorcycle, the first controller  120  does not start the engine until authentication is performed even when a start button  162  is pressed. 
     The first controller  120  can control the output circuit  141  to generate the theft alarm signal when the first controller  120  receives a sensing signal from the motor sensor of the sensor unit  113  in an alarm mode. When the motion sensor senses titling of the motorcycle to the left or right at greater than a predetermined angle or lifting of the front or rear wheel of the motorcycle at greater than a predetermine angle, the motion sensor outputs a sensing signal corresponding to the tilting or lifting to the first controller  120 . Then, the first controller  120  controls the output circuit  141  to generate the theft alarm signal. 
     The first controller  120  can automatically perform warning, cancellation of warning, power-up and start-up through radio communication with the smart remote controller  200  via the first radio communication unit  130 . Of course, the first controller  120  automatically carries out radio communication with the smart remote controller  200  which passes authentication. When authentication through the smart remote controller  200  is successful, the first controller  120  automatically cancels predetermined handle lock. When the engine cuts off and the motorcycle enters the alarm mode, the first controller  120  sets the handle lock. 
     When the first controller  120  receives a pressure sensing signal from the pressure sensor of the sensor unit  113  or senses a braking operation, the first controller  120  can start authentication of the smart remote controller  200 . For example, the first controller  120  can transmit the electronic identifier of the electronic control unit  100  to the smart remote controller  200  or requests the smart remote controller  200  to transmit the electronic identifier of the smart remote controller  200 . 
     The first controller  120  maintains a sleep state while the motorcycle engine cuts off. That is, the first controller  120  maintains the sleep state during a period for which a battery of the motorcycle is in danger of discharging while the motorcycle engine cuts off. Further, the first controller  120  can check a battery voltage of the motorcycle and, when the motorcycle is in danger of battery discharging, notify a user of the danger of battery discharging through the siren  142 , the lamp  143  or an LED  152 . 
     The LED  152  indicates an operating state of the motorcycle. The first controller  120  can control a status indicating circuit  151  to operate the LED  152 . 
     The electronic control unit  100  according to the current embodiment of the invention can be attached to the motorcycle when the motorcycle is manufactured. If the electronic control unit  100  is attached to a finished motorcycle, there is no need to additionally attach the lamp  143 , the start button  162  and the siren  142  to the motorcycle and those previously attached to the motorcycle can be used. Accordingly, the electronic control unit  100  can be conveniently mounted in the motorcycle. 
     Referring to  FIG. 2 , the smart remote controller  200  according to an embodiment of the present invention includes a second radio communication unit  210 , a second controller  220 , a battery  230 , a buzzer  242 , and a lamp  243 . The second radio communication unit  210  includes an LF receiver  211  and an RF transmitter  212 . The LF receiver  211  receives the electronic identifier of the electronic control unit  100 , transmitted from the electronic control unit  100 . In another embodiment of the invention, the LF receiver  211  can receive a smart remote controller electronic identifier transmission request signal from the electronic control unit  100 . The RF transmitter  212  transmits a response signal of the smart remote controller  200  to the electronic control unit  100 . 
     The second controller  220  determines whether the electronic identifier of the electronic control unit  100 , received through the LF receiver  211 , is identical to the electronic identifier of the smart remote controller  200 . When the electronic identifier of the electronic control unit  100  is not identical to the electronic identifier of the smart remote controller  200 , the second controller  220  does not respond to the electronic control unit  100 . When the electronic identifier of the electronic control unit  100  is identical to the electronic identifier of the smart remote controller  200 , the second controller  220  controls the RF transmitter  212  to transmit a response signal including the electronic identifier of the smart remote controller  200  to the electronic control unit  100 . 
     Further, the second controller  220  maintains a sleep state until an electronic identifier request signal is received from the electronic control unit  100 . The second controller  220  can check the voltage of a battery  230  of the smart remote controller  200  and notify the user of a battery change time through the lamp  243 . The second controller  220  does not send an unnecessary response when the second controller  220  receives an electronic identifier request from an electronic control unit of a motorcycle other than the authenticated electronic control unit  100  of the motorcycle, and thus signal collision can be prevented. The second controller  220  can receive the theft alarm signal from the electronic control unit  100  through the LF receiver  211  and output a theft alarm. For example, the second controller  220  can raise the theft alarm through the buzzer  242  or the lamp  243  to notify the user that the motorcycle is in danger of being stolen. Here, the lamp  243  can use an LED. 
     When the user wants to ride the motorcycle, the user presses the start button  162  while carrying the smart remote controller  200 . In another embodiment of the invention, the user can insert the key into the key cylinder, turn the key cylinder to ‘ON’ position, and then press the start button  162  or step on the kick start to start the motorcycle. Here, the key cylinder may be one of a 2-pin and 4-pin type key cylinder. 
     A signal of the start button  162  is transmitted to the first controller  120  through an input circuit  161 . The sensing unit  110  senses motorcycle power-up or engine start-up. Even if the motorcycle is powered up or the motorcycle engine is started through an illegal method, the sensing unit  110  senses the illegal power-up or engine start-up. When the sensing unit  110  senses the power-up or engine start-up, the first controller  120  transmits the electronic identifier of the electronic control unit  100  to the smart remote controller  200  through the first radio communication unit  130 . 
     The smart remote controller  200  receives the electronic identifier of the electronic control unit  100  through the LF receiver  211 . The second controller  220  determines whether the received electronic identifier of the electronic control unit  100  is identical to the electronic identifier of the smart remote controller  200 . When the received electronic identifier of the electronic control unit  100  is not identical to the electronic identifier of the smart remote controller  200 , the second controller sends no response. When the received electronic identifier of the electronic control unit  100  correspond to the electronic identifier of the smart remote controller  200 , the second controller  220  transmits a response signal including the electronic identifier of the smart remote controller  200  to the electronic control unit  100  through the RF transmitter  212 . In this manner, the smart remote controller  200  responds to only the electronic control unit  100  having the electronic identifier identical to that of the smart remote controller  200 , and thus an unnecessary operation can be prevented. 
     The first controller  120  of the electronic control unit  100  determines that illegal power-up or engine start-up is performed and cuts off the power-up or engine start-up if the first controller  120  does not receive the response signal through the first radio communication unit  130  for a predetermined time. The first controller  120  can ground the output of an IG control circuit  171  to the ground in order to cut off the engine. That is, the electronic control unit  100  can ground the output of the IG control circuit to the ground such that AC power supplied to an engine ignition controller  173  from a generator to the ground so as to stop the engine or cut off DC power supplied to the engine ignition controller  173  so as to stop the engine. For example, the engine ignition controller  173  may use one of capacitor discharge ignition (CDI), DC-CDI and injection using the electronic control unit  100 . 
     In the case of a motorcycle using the CDI type engine ignition controller  173 , AC power supplied to the engine ignition controller  173  or AC power supplied to an ignition coil can be grounded to the ground to stop engine start-up. A 4-pin type key cylinder can be used the CDI type engine ignition controller, 
     In the case of a motorcycle using the DC-CDI type engine ignition controller  173 , DC power supplied to the engine ignition controller  173  can be cut off by using a switch or a relay to stop engine start-up. A 2-pin type key cylinder can be used for the DC-CDI engine ignition controller. Further, the DC-CDI type engine ignition controller  173  performs a function of stopping engine start-up when a specific pin is grounded to the ground according to the type. 
     In the case of a motorcycle employing the injection type engine ignition controller  173  using the electronic control unit  100 , DC power supplied to the ignition coil can be cut by using a switch or a relay to stop the engine start-up. For the injection type engine ignition controller, a 2-pin type key cylinder can be used. 
     As described above, a relay or a switch can be additionally connected between the IG control circuit  171  and the engine ignition controller  173  according to motorcycle type to control starting of the aforementioned engine ignition controllers  173  of three types by using the IG control circuit  171 . 
     The first controller  120  can control the output circuit  141  to output the theft alarm signal. The theft alarm signal may correspond to the siren  142  or light emitted from the lamp  143 . 
     When the first controller  120  receives the response signal through the first radio communication unit  130 , the first controller  120  determines whether the electronic identifier of the smart remote controller  200 , included in the response signal, is identical to the electronic identifier of the electronic control unit  100 . When the electronic identifier of the smart remote controller  200  is identical to the electronic identifier of the electronic control unit  100 , the first controller  120  maintains start-up of the engine. 
     When the user wants to stop the motorcycle, he or she should stop start-up of the motorcycle engine. A stop button may be used to stop start-up of the motorcycle engine. The user can press the stop button to stop the motorcycle engine after he or she ends driving of the motorcycle. 
     Another method of stopping the motorcycle engine stops the engine when the user presses the start button  162  for longer than a predetermined time while engine start-up is sensed. In this case, the additional stop button is not required. 
       FIG. 3  is a flowchart showing an antitheft method for motorcycles according to an embodiment of the present invention. 
     Referring to  FIGS. 1 ,  2  and  3 , the electronic control unit  100  of the motorcycle senses power-up of the motorcycle or engine start-up before authentication in step S 310 . The power-up of the motorcycle and engine start-up can be sensed by the sensing unit  110 . When the power-up or engine start-up is sensed, the electronic control unit  100  transmits the electronic identifier of the electronic control unit  100  to the smart remote controller  200  in step S 320 . The electronic identifier of the electronic control unit  100  can be transmitted through the LF transmission circuit  131  and the LF antenna  132 . The smart remote controller  200  can receive the electronic identifier of the electronic control unit  100  through the LF receiver  211 . The smart remote controller  210  determines whether the received electronic identifier of the electronic control unit  100  is identical to the electronic identifier of the smart remote controller  200  in step S 330 . 
     Here, if a pressure sensing signal is received from the pressure sensor attached to the seat of the motorcycle or a braking operation is sensed in step S 320 , the electronic control unit  100  can transmit the electronic identifier of the electronic control unit  100  to the smart remote controller  200  through radio communication. 
     When the electronic identifier of the electronic control unit  100  is not identical to the electronic identifier of the smart remote controller  200 , the smart remote controller  200  does not respond to the electronic control unit  100  in step S 340 . In this manner, the smart remote controller  200  responds to only the electronic control unit  100  having the electronic identifier identical to that of the smart remote controller  200 , and thus an unnecessary operation can be prevented from being performed. Accordingly, signal collision can be prevented. When the smart remote controller  200  does not respond to the electronic control unit  100 , the electronic control unit  100  cannot receive a response signal within a predetermined time. The electronic control unit  100  cuts off power-up of the motorcycle or stops engine start-up if the response signal is not received in step S 351 . In the current embodiment of the invention, the electronic control unit  100  can ground the output of the IG control circuit  171  to the ground to make AC power supplied to the engine ignition controller from a generator drain to the ground so as to stop the engine or cut off DC power supplied to the engine ignition controller so as to stop the engine. In another embodiment of the invention, the engine can be stopped through other methods. That is, the present invention can prevent the motorcycle from being illegally started by cutting off power-up or engine start-up. 
     Further, electronic control unit  100  generates a theft alarm signal in step S 352 . The theft alarm signal may correspond to the siren  142  or flicking of the lamp  143 . The theft alarm signal informs people that the motorcycle is in danger of being stolen to prevent the motorcycle from being stolen. 
     The electronic control unit  100  maintains a predetermined handle lock state in step S 340 . 
     When the electronic identifier of the electronic control unit  100  is identical to the electronic identifier of the smart remote controller  200 , the smart remote controller  200  transmits the response signal to the electronic control unit  100  in step S 360 . The response signal includes the electronic identifier of the smart remote controller  200 . The response signal can be transmitted through the RF transmitter  212 . The electronic control unit  100  can receive the response signal from the smart remote controller  200  through the RF antenna  134  and the RF receiving circuit  133 . The electronic control unit  100  determines whether the electronic identifier of the smart remote controller  200 , which is included in the response signal, is identical to the electronic identifier of the electronic control unit  100  in step S 370 . In this manner, the electronic control unit  100  also determines whether the electronic identifiers of the electronic control unit  100  and the smart remote controller  200  are identical to each other, and thus safer security can be achieved. For example, if only the smart remote controller  200  determines whether the electronic identifiers of the electronic control unit  100  and the smart remote controller  200  are identical to each other, a person having illegal purpose can easily steal the motorcycle by operating the smart remote controller  200 . To prevent this, the electronic control unit  100  is required to determine whether the electronic identifiers of the electronic control unit  100  and the smart remote controller  200  are identical to each other. 
     If the electronic identifiers of the electronic control unit  100  and the smart remote controller  200  are not identical to each other, the electronic control unit  100  cuts off motorcycle power-up or engine start-up in step S 351 . Further, the electronic control unit  100  generates the theft alarm signal in step S 352 . If the electronic identifiers of the electronic control unit  100  and the smart remote controller  200  are identical to each other, the electronic control unit  100  prepares or maintains engine start-up in step S 380 . The electronic control unit  100  maintains the predetermined handle lock state when the electronic identifiers of the electronic control unit  100  and the smart remote controller  200  are not identical to each other. On the other hand, the electronic control unit  100  cancels the predetermined handle lock state when the electronic identifiers of the electronic control unit  100  and the smart remote controller  200  are identical to each other. 
     If the motion sensor of the sensor unit  113  senses tilting of the motorcycle to the left or right at greater than a predetermined angle or lifting of the front or rear wheel of the motorcycle at greater than a predetermined angle in step S 310 , the motion sensor outputs a sensing signal to the electronic control unit  100 . When the electronic control unit  100  receives the sensing signal, the electronic control unit  100  can generate the theft alarm signal and output the theft alarm signal through the output circuit  141 . 
     The electronic control unit  100  can transmit the theft alarm signal to the authenticated smart remote controller  200  in step S 352 . When the smart remote controller  200  receives the theft alarm signal, the smart remote controller  200  can output a theft alarm through the buzzer  242  or the lamp  243  to inform the user that the motorcycle is in danger or being stolen. 
       FIG. 4  is a flowchart showing an antitheft method for motorcycles according to another embodiment of the present invention. 
     Referring to  FIG. 4 , the electronic control unit  100  senses motorcycle power-up or engine start-up before authentication in step S 410 . The motorcycle power-up or engine start-up can be sensed by the sensing unit  110 . When the motorcycle power-up or engine start-up is sensed, the electronic control unit  100  requests the smart remote controller  200  to transmit the electronic identifier of the smart remote controller  200  in step S 420 . Here, the electronic control unit  100  requests the smart remote controller  200  to transmit the electronic identifier of the smart remote controller  200  through the first radio communication unit  130 . The smart remote controller  200  transmits the electronic identifier thereof to the electronic control unit  100  at the request of the electronic control unit  100  in step S 430 . The smart remote controller  200  can transmit the electronic identifier thereof through the second radio communication unit  210 . The electronic control unit  100  receives the electronic identifier of the smart remote controller  200  and determines whether the electronic identifier of the electronic control unit  100  is identical to the electronic identifier of the smart remote controller  200  in step S 440 . 
     If a pressure sensing signal is received from the pressure sensor attached to the seat of the motorcycle or a braking operation is sensed in step S 420 , the electronic control unit  100  can request the smart remote controller  200  to transmit the electronic identifier of the smart remote controller  200  through radio communication. 
     When the electronic identifier of the electronic control unit  100  is not identical to the electronic identifier of the smart remote controller  200 , the electronic control unit  100  cuts off motorcycle power-up or engine start-up in step S 451 . Further, the electronic control unit  100  generates a theft alarm signal in step S 452 . When the electronic identifier of the electronic control unit  100  is identical to the electronic identifier of the smart remote controller  200 , the electronic control unit  10  prepares or maintains engine start-up in step S 460 . 
     The antitheft method for motorcycles according to the current embodiment of the invention can achieve rapid authentication as compared to the antitheft method for motorcycles described with reference to  FIG. 3 . 
     While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.