Patent Document

BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an engine starting system applied to a propelled object including a vehicle which is propelled by an engine (internal combustion engine) mounted thereon (for example, a two-wheeled vehicle, a four-wheeled vehicle, an all terrain vehicle (ATV), a ship, a jet-propulsion watercraft, or the like), and more particularly to a technique of preventing a battery from running out (a battery voltage from dropping) due to tampering of a switch by a third party, the switch being manually actuated for starting the engine. 
     2. Description of the Related Art 
     Conventionally, a vehicle using a portable electronic key (portable equipment) is provided with a starting switch which is manually actuated. For example, in a case of a four-wheeled vehicle, the switch is provided to a door handle or a trunk lid of the vehicle. When the switch is actuated by a driver, the switch communicates with the electric key so as to obtain an ID number from the electric key. The ID number is collated with an ID number registered in a control device (equipment on the propelled object side) installed on the vehicle side, and when the ID numbers coincide with each other, the door lock is released. 
     Also, in a case of a two-wheeled vehicle, there has been proposed a system capable of reliably protecting the vehicle against theft based on a system similar to that for a four-wheeled vehicle. 
     For example, there has been disclosed an engine starting system for regularly starting an engine mounted on a propelled object, which includes: equipment on a propelled object; a switch; portable equipment; steering unlocking section; power activating section; and an engine control unit, the equipment on a propelled object transmitting, in response to an actuation signal from the switch, an inquiry signal including a collation code to the portable equipment, the portable equipment transmitting an answer signal including a cipher code corresponding to the inquiry signal, the equipment on the propelled object side allowing the engine to start by causing the engine control unit to operate, in a case where the answer signal corresponds to the inquiry signal, by unlocking the steering unlocking section and activating the power activating section, in which the equipment on the propelled object side executes an unlocking operation of the steering unlocking section, an operation to turn ON the power activating section, or a cranking operation by the engine control unit (refer to, for example, JP 2006-137338 A). 
     When the conventional engine starting system is applied to a two-wheeled vehicle, it is necessary to take countermeasures against tampering more adequately than in the case of a four-wheeled vehicle. In particular, in a case of a conventional mechanical key cylinder, there has been adopted a mechanism capable of preventing the lock from being forced open with a screw driver or preventing a key inserting hole from being stuffed with a foreign object or being operated. Even in a case of an electronic key, operating an activation switch provided outside of a vehicle leads to start collating IDs with portable equipment, and therefore it is presumed that the switch is repeatedly pushed by a third party. When the switch is actuated by being pushed by a third party, equipment on a propelled object side is activated and transmits radio waves in order to communicate with the portable equipment side. Accordingly, the equipment transmits radio waves every time the switch is actuated even if the portable equipment of the vehicle does not exist, and therefore the battery is consumed and several amperes of current flows therethrough. Therefore, if the switch is tampered and actuated too many times, it may leads to a problem that the battery is made impossible to start the engine due to a power supply voltage drop, that is, the battery runs out. 
     There has also been a problem that a radio wave transmission portion becomes overheated due to the repetitive actuation of the switch, which leads to a deterioration of a circuit and a failure of the engine starting system. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in view of the above-mentioned problems, and it is an object of the invention to provide an engine starting system which is highly reliable in that a battery does not run out even if a manual switch is tampered and actuated many times by a third party. 
     According to the present invention, there is provided an engine starting system for regularly starting an engine mounted on a propelled object, including: power activating section; an engine control unit; equipment on the propelled object side; steering unlocking section; alarming section; a switch capable of being manually actuated; which are mounted on the propelled object; and portable equipment possessed by a driver of the propelled object; the equipment on the propelled object side transmitting an inquiry signal including a collation code in response to an actuation signal of the switch, the portable equipment transmitting an answer signal including a cipher code corresponding to the inquiry signal to the equipment on the propelled object side, the equipment on the propelled object side unlocking the steering unlocking section while causing the engine control unit to operate by activating the power activating section in a case where the answer signal corresponds to the inquiry signal, thereby allowing the engine to start, in which the equipment on the propelled object side includes actuation signal refusing section which avoids responding to the actuation signal from the switch for a third predetermined time in at least one of the states where a number of actuation signals successively transmitted from the switch without producing an answer signal thereto has become equal to or larger than a prescribed number of times predetermined in a first predetermined time period and where the actuation signal has been kept tuned ON for a period equal to or longer than a second predetermined time period without producing an answer signal thereto. 
     According to the present invention, it is possible to prevent the abnormal consumption of a battery and overheating of a transceiver even if the switch which is operated for starting the engine is unnecessarily operated due to tampering or the like, without specifically providing additional hardware. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  is a block diagram schematically showing an engine starting system according to an embodiment of the present invention; 
         FIG. 2  is a block diagram concretely showing the on-vehicle equipment of  FIG. 1  and peripheral equipment thereof; 
         FIG. 3  is a perspective view showing a concrete structural example of steering unlocking section according to the present invention; 
         FIG. 4  is an explanatory diagram showing state transitions during operation of the system according to an embodiment of the present invention; 
         FIG. 5  is a timing chart showing an operation performed when a switch is actuated through a short-time push in the engine starting system according to an embodiment of the present invention; 
         FIG. 6  is a timing chart showing an operation performed when a switch is actuated through a long-time push in the engine starting system according to an embodiment of the present invention; 
         FIG. 7  is a timing chart for explaining control to be exerted in accordance with a switching operation in the engine starting system according to an embodiment of the present invention; 
         FIG. 8  is a timing chart for explaining control to be exerted in accordance with a switching operation in the engine starting system according to an embodiment of the present invention; 
         FIG. 9  is a timing chart for explaining control to be exerted in accordance with a switching operation in the engine starting system according to an embodiment of the present invention; and 
         FIG. 10  is a timing chart for explaining control to be exerted in accordance with a switching operation in the engine starting system according to an embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiment 1 
       FIG. 1  is a block diagram schematically showing the overall structure of an engine starting system for a vehicle or the like which is a propelled object according to Embodiment 1 of the present invention. Illustrated in  FIG. 1  is an example in which the present invention is applied to a two-wheeled vehicle. In  FIG. 1 , the engine starting system includes portable equipment  1  and on-vehicle equipment  2  constituting equipment on the propelled object side. 
     The portable equipment  1 , which is possessed by an authorized driver (user), includes a transmitting circuit  10 , a receiving circuit  11 , a control circuit  12 , a memory circuit  13  in which a cipher code is stored, and a battery  14  serving as a power source. The control circuit  12  operates by being supplied with power from the battery  14 , reads the cipher code from the memory circuit  13 , and carries out radio communication with the on-vehicle equipment  2  via the transmitting circuit  10  and the receiving circuit  11 . 
     On the other hand, the on-vehicle equipment  2  installed in the vehicle includes a transmitting circuit  20 , a receiving circuit  21 , a control circuit  22 , a memory circuit  23  in which a cipher code for collation (herein after, referred to as “the collation code”) is stored, and an input/output circuit  24 . The control circuit  22  operates by being supplied with power from an on-vehicle battery  9 , reads the collation code from the memory circuit  23 , and carries out radio communication with the portable equipment  1  via the transmitting circuit  20  and the receiving circuit  21 . 
     The portable equipment  1  and the on-vehicle equipment  2  exchange radio communication signals  101  and  102  with each other via the transmitting circuit  10  and the receiving circuit  11 , and via the transmitting circuit  20  and the receiving circuit  21 . 
     A switch  31  constructed of an external actuating button on the vehicle side is connected to the control circuit  22  in the on-vehicle equipment  2 . In response to an actuation signal of the switch  31 , the control circuit  22  performs calculation based on a driving state and a collation result to obtain a control signal  27 , and outputs the control signal  27  to an external relay or the like (which will be described later) via the input/output circuit  24 . Further, the control circuit  22  is connected to an engine control unit  8  via the input/output circuit  24  and a communication line  100 . 
       FIG. 2  is a block diagram which concretely shows the structure of the on-vehicle equipment  2  of  FIG. 1  in relation to the engine control unit  8  and peripheral equipment. Referring to  FIG. 2 , connected to the on-vehicle equipment  2  are a system relay  6 , a starter relay  41  for energizing a starter (motor)  4  from the on-vehicle battery  9 , a steering unlocking sensor  51 , a steering unlocking section  52 , an indicator lamp  53  for indicating various kinds of information, a hazard relay  54  for triggering an alarm, an alarm buzzer  55 , and an oscillation sensor  56  for detecting theft, as well as the aforementioned components such as the engine control unit  8 , the on-vehicle battery  9 , and the switch  31 . 
     A sensor group and a relay group including the system relay  6 , the starter relay  41 , and the like constitute the peripheral equipment of the on-vehicle equipment  2 . The on-vehicle equipment  2  includes, in addition to the respective circuits  20  to  24  mentioned above, a starter relay driving circuit  25  for driving the starter relay  41  and a power supply circuit  26  connected to the on-vehicle battery  9  to supply power to the control circuit  22 . 
     The starter relay driving circuit  25 , the steering unlocking sensor  51 , and the oscillation sensor  56  are connected to the control circuit  22  in the on-vehicle equipment  2 . Further, the control signal  27  from the input/output circuit  24  is input to the system relay  6 , the steering unlocking section  52 , the indicator lamp  53 , the hazard relay  54 , and the alarm buzzer  55 . 
     The engine control unit  8 , which includes an engine control circuit  81 , a power supply circuit  82  connected to the engine control circuit  81 , an input circuit  83 , and an input/output circuit  84 , drivingly controls an engine  70  via each of the various actuators (an ignition coil, injectors, a fuel pump, and the like)  71 . In the engine control unit  8 , the power supply circuit  82  is connected to the on-vehicle battery  9  via the system relay  6  and supplies power to the engine control circuit  81 . 
     A tip-over sensor  72  is connected to the input circuit  83 , and the various actuators  71  are connected to the input/output circuit  84 . The engine control unit  8  and the various actuators  71  are supplied with power from the on-vehicle battery  9  via the system relay  6 . The input/output circuit  84  in the engine control unit  8  is connected to the input/output circuit  24  in the on-vehicle equipment  2  via the communication line  100  permitting bidirectional communication. 
       FIG. 3  is a perspective view showing a concrete structural example of the steering unlocking section  52  in  FIG. 2 , which is designed for use in a two-wheeled vehicle. Referring to  FIG. 3 , the steering unlocking section  52  includes an electromagnetic solenoid  521  energized at the time of an unlocking operation, a stopper  522  serving as an operating portion of the electromagnetic solenoid  521 , a lock bar  523  engaging the stopper  522 , a catch portion (recess)  524  formed in a central upper face of the lock bar  523 , an operating end portion  525  of the lock bar  523 , a spring  526  urging the lock bar  523  in an unlocking direction (to the right in  FIG. 3 ), and a lock button  527  serving as an actuating portion of the lock bar  523 . 
     When a steering (handle) is locked, the stopper  522  of the electromagnetic solenoid  521  is caught in the catch portion  524  of the lock bar  523 , and the operating end portion  525  of the lock bar  523  is caught in a rotational member (not shown) of the steering, to thereby lock the steering so as not to rotate. 
     In the engine starting system shown in  FIGS. 1 and 2 , the on-vehicle equipment  2  transmits an inquiry signal (trigger signal)  102  from the transmitting circuit  20  in response to an actuation signal of the switch  31 . The portable equipment  1  possessed by the driver then receives the inquiry signal  102  from the on-vehicle equipment  2 , and returns an answer signal  101  for the inquiry signal  102  to the on-vehicle equipment  2 . 
     As a result, the control circuit  22  in the on-vehicle equipment  2  thereby determines whether or not the answer signal  101  received from the portable equipment  1  corresponds to the inquiry signal  102 . If it is determined that the answer signal  101  is authentic, the control circuit  22  generates and outputs the control signal  27  for unlocking from the input/output circuit  24 , drives the steering unlocking section  52 , unlocks the steering of the vehicle, and permits the engine  70  to be started. 
     At this moment, only by repeatedly actuating (pushing) the single switch (button)  31  attached to the vehicle, the steering unlocking section  52  is driven, the system relay  6  is turned ON, power supply circuits (vehicular power sources)  26  and  82  supplied with power from the on-vehicle battery  9  are activated (the power source for the system is turned ON), and a cranking section is driven (the engine  70  is started). 
     A short-time repetitive actuation (ON/OFF) or a long-time continuous actuation (continuous ON) can be selected as an actuation mode of the switch  31 . For example, if a sequential shift of control is made through the short-time repetitive actuation of the switch  31 , a determination on authenticity is made by the inquiry signal  102  and the answer signal  101  every time the switch  31  is actuated. Further, if a continuous shift of control is made through the long-time continuous actuation of the switch  31 , a determination on authenticity is made by the inquiry signal  102  and the answer signal  101  at the first time only. Still further, the control of turning the power source of the system OFF (stopping the engine  70 ) via the system relay  6  can also be performed by actuating the switch  31 . 
     Also, the system relay  6  constitutes power activating section, the on-vehicle equipment  2  constitutes the equipment on the propelled object side, the indicator lamp  53 , the hazard relay  54 , the alarm buzzer  55 , and the oscillation sensor  56  constitute alarming section, the transmission circuit  10  and the receiving circuit  11  constitute a transceiver on the portable equipment side, and the transmission circuit  20  and the receiving circuit  21  constitute a transceiver on the propelled object side. 
     Next, specific operations of the respective circuits shown in  FIGS. 1 and 2  will be described. First of all, if the driver (user) possessing the authenticated portable equipment  1  enters the vehicle and actuates the switch  31 , the control circuit  22  in the on-vehicle equipment  2  reads the collation code from the memory circuit  23 , and transmits by radio a trigger signal for cipher collation as the inquiry signal  102  via the transmitting circuit  20 . 
     At this moment, if the driver (user) possessing the portable equipment  1  exists within a transmission range of the on-vehicle equipment  2 , the receiving circuit  11  in the portable equipment  1  receives the inquiry signal (trigger signal)  102 . Even if someone who does not possess the portable equipment  1  has actuated the switch  31 , communication, collation, or the like of signals does not occur. 
     The control circuit  12  in the portable equipment  1  then refers to the collation code included in the inquiry signal  102  and determines whether to transmit a cipher code or not. The determination processing performed herein can be replaced with a processing of determining whether or not a so-called ID code has been received. In other words, the control circuit  12  can respond only to the collation code transmitted from the driver&#39;s own vehicle by determining from which vehicle the collation code received from the on-vehicle equipment  2  has been transmitted. 
     If it is determined that the received collation code has been transmitted from the driver&#39;s own vehicle, the control circuit  12  invokes the cipher code from the memory circuit  13  and transmits the cipher code by radio as the answer signal  101  via the transmitting circuit  10 . 
     The battery  14  in the portable equipment  1  is a power supply source for operating the respective circuit portions. Until the subsequent inquiry signal  102  is received after the answer signal  101  has been transmitted, the battery  14  waits to receive the inquiry signal  102  in a low-consumption mode to prevent power consumption in the power supply source. In order to make power supply possible by activating the battery  14  upon receiving the inquiry signal  102 , the battery  14  is designed as an energy-efficient battery capable of restraining power consumption. 
     The on-vehicle equipment  2  receives the answer signal  101  (including the cipher code) from the portable equipment  1  via the receiving circuit  21 . The control circuit  22  in the on-vehicle equipment  2  invokes the collation code stored in the memory circuit  23  and collates the collation code with the received cipher code. 
     If, for example, the steering wheel has been locked when it is determined as a result of collation that the collation code coincides with the cipher code, the control circuit  22  outputs the control signal  27  for “unlocking” from the input/output circuit  24 . 
     If the user actuates the switch  31  again at this moment, the collation of ID codes is carried out as described above. If it is determined as a result that the ID codes (the cipher code and the collation code) coincide with each other, the control circuit  22  in the on-vehicle equipment  2  generates and outputs the control signal  27  from the input/output circuit  24 , turns the system relay  6  ON, and activates the engine control unit  8 . 
     The control circuit  22  outputs an engine start permitting signal to the engine control unit  8  via the communication line  100 . If the cipher code and the collation code do not coincide with each other, the control signal  27  is not generated from the on-vehicle equipment  2  and the system relay  6  is not turned ON. 
     Further, as described above, the steering unlocking sensor  51  for detecting the unlocking of the steering and the oscillation sensor  56  sensing the occurrence of theft by detecting oscillation of the vehicle when the engine is not allowed to operate are connected to the control circuit  22 . Still further, connected to the input/output circuit  24  are the steering unlocking section  52  for unlocking the steering, the indicator lamp  53  indicating various kinds of information (e.g., an abnormality in the steering unlocking section  52 , an abnormality in activation of the engine control unit  8 , a warning in the event of theft), the hazard relay  54  issuing the same kinds of warnings (e.g., using a flasher lamp to provide an answerback indication in response to the coincidence between collation results or driving the flasher lamp to emit flashes of light as a warning in the event of theft), and the alarm buzzer  55  issuing warning sound in the event of theft. 
     Furthermore, the engine control circuit  81  in the engine control unit  8  (the section for controlling the operation of the engine  70 ) outputs a drive signal corresponding to an operation state of the engine  70  via the input/output circuit  84 , actuates the various actuators  71 , and prohibits the operation of the engine  70 . In addition to the tip-over sensor  72  for detecting tip-over of the vehicle, various sensors (not shown) for detecting driving states (intake air temperature, engine coolant temperature, intake air amount, and the like) necessary to control the engine are connected to the engine control circuit  81 . 
     An unlocking operation performed by the steering unlocking section  52  in response to the coincidence between cipher collation results will now be described. Referring to  FIG. 3 , if power is supplied to the electromagnetic solenoid  521  to release the stopper  522  caught in the catch portion  524  of the lock bar  523  in the direction indicated by an arrow C, the lock bar  523  moves toward the lock button  527  (to the right in  FIG. 3 ) due to a restoring force of the spring  526 . Then, the operating end portion  525  is released from the catch portion of the rotational member (not shown) of the steering, whereby the unlocking operation is completed. It is to be noted herein that the steering is locked manually by pushing the lock button  527 . 
     Referring to  FIG. 4  as well as  FIGS. 1 to 3 , it will now be described how the driver unlocks the steering wheel and activates the engine  70 .  FIG. 4  is an explanatory diagram showing state transitions during operation of the system according to the first embodiment of the present invention. A flowchart in this drawing shows how the specialized system operation in the two-wheeled vehicle shifts from a steering unlocking mode to the permission of the operation of the engine  70  through an engine starting mode. 
     Referring to  FIG. 4 , first of all, the system is OFF in its initial state (when the steering wheel is locked) (step  601 ). 
     At this time, if the switch  31  is pushed for a short time, the control circuit  22  in the on-vehicle equipment  2  responds thereto and compares the cipher code received from the portable equipment  1  with the collation code to authenticate the portable equipment  1  (step S 1 ). 
     If it is determined in step S 1  that the cipher code coincides with the collation code, the steering wheel is unlocked with the system being OFF (step  602 ). 
     On the other hand, if it is determined that the cipher code does not coincide with the collation code, the current mode, that is, the OFF state of the system (step  601 ) is maintained. 
     In addition, if the switch  31  is pushed for a short time with the steering wheel being unlocked (step  602 ), the control circuit  22  in the on-vehicle equipment  2  compares again the cipher code received from the portable equipment  1  with the collation code and authenticates the portable equipment  1  (step S 2 ). 
     If it is determined in step S 2  that the cipher code coincides with the collation code, the control circuit  22  activates the system relay  6 . 
     In the manner as described above, the system is turned ON (while the engine  70  is still stopped) (step  603 ). 
     At this moment, the engine control unit  8  starts up, and at the same time, the control circuit  22  delivers an engine start permitting signal to the engine control unit  8  via the communication line  100  and thus permits the various actuators  71  to be started. 
     Further, if it is desired to return the system from ON (step  603 ) to OFF, the switch  31  is pushed for a long time (the portable equipment  1  is authenticated) (step S 3 ). 
     In response to this, the control circuit  22  stops driving the system relay  6 , and as a result, the system is turned OFF again (step  602 ). 
     Further, if the system is left to remain ON (step  603 ), the on-vehicle equipment  2  stops driving the system relay  6  after the lapse of a predetermined period of time T [seconds] (e.g., 600 seconds: fourth predetermined period of time) (step  605 ) and shifts the system to the OFF mode (step  602 ). 
     On the other hand, if the switch  31  is pushed again for a short time (step S 5 ) with the system being ON (step  603 ), the control circuit  22  turns the starter relay  41  ON via the starter relay driving circuit  25 . 
     As a result, the starter  4  is driven over a predetermined period of time Ts [seconds] (e.g., 3 seconds: fifth predetermined period of time). Thus, the engine  70  can be cranked with the system being ON (step  604 ). 
     If the engine  70  has gone through an explosion stroke immediately after the lapse of the predetermined period of time Ts (3 seconds) or within the predetermined period of time Ts (step S 8 ), the engine  70  is started or activated with the system being ON (step  606 ). 
     At this moment, if it is desired to stop only rotation of the engine  70 , stoppage of the engine can be realized by turning a kill switch, that is, an engine stop SW (not shown) ON (step S 6 ). 
     On the other hand, in the case where engine stall has occurred (step S 9 ) with the system being ON (step  604 ) or in the case where the engine is stopped again (step S 10 ) with the engine  70  being started or activated (system ON) (step  606 ), the system returns to the state where the system is turned ON while the engine is still stopped (step  603 ). 
     If it is desired to stop the engine  70  while the engine  70  is rotating (S 606 ) after cranking (step  604 ), the system can be switched OFF (step  602 ) by pushing the switch  31  for a long time (step S 7 ). 
     If it is desired to make a shift from the OFF state of the system with the unlocked steering wheel (step  602 ) to the OFF state of the system with the locked steering wheel (step  601 ), it is sufficient just to push the lock button  527  manually (see  FIG. 3 ) (step S 11 ). 
     Further, if it is desired to make a shift from the OFF state of the system with the locked steering wheel (step  601 ) to the ON state of the system with the cranking engine (step  604 ) by starting the engine at once, the switch  31  is pushed for a long time (the portable equipment  1  is authenticated) (step S 4 ). 
     In response to this, the control circuit  22  turns the steering unlocking section  52  and the system relay  6  ON and issues a cranking command to the engine control unit  8  almost simultaneously. As a result, a direct shift from the OFF state of the system (step  601 ) to the cranking state (step  604 ) can be made. 
     At this moment, since the control circuit  22  performs, in step S 4 , the processing of comparing the cipher code of the portable equipment  1  with the collation code only once, the time required for a shift to the starting mode can be reduced. 
     Next, referring to timing charts shown in  FIGS. 5 and 6 , it will be described more specifically how the control circuit  22  in the on-vehicle equipment  2  operates depending on how long the switch  31  is actuated (i.e., whether the switch  31  is pushed for a short time or for a long time). 
       FIG. 5  shows how the control circuit  22  operates when the switch  31  is sequentially actuated through a short-time push, and  FIG. 6  shows how the control circuit  22  operates when the switch  31  is actuated through a long-time push. 
     In  FIGS. 5 and 6 , the actuation of the switch  31  by the driver (user), the operation of comparing cipher codes in the on-vehicle equipment  2 , the unlocking operation of the steering unlocking section  52  by the control circuit  22 , and the operation of activating and stopping the system relay  6  by the control circuit  22  are illustrated together with changes in the rotational speed of the engine  70 . 
     Further, timings for actuating the switch  31  are shown in relation to the respective steps S 1 , S 2 , S 4 , S 5 , and S 7  in  FIG. 4 . 
     First, as shown in  FIG. 5 , if the switch  31  is repeatedly and sequentially actuated for a short time (steps S 1 , S 2 , and S 5 ) with the system being OFF and the steering being locked, the control circuit  22  in the on-vehicle equipment  2  performs the processing of comparing cipher codes every time after the switch  31  has been actuated through a short-time push. If it is determined that the cipher codes coincide with each other, the control circuit  22  performs a processing corresponding to the timing of actuation. 
     That is, in response to the first short-time push (step S 1 ), the cipher codes are compared with each other and then unlocking operation of the steering unlocking section  52  is performed. In response to the subsequent short-time push (step S 2 ), the cipher codes are compared with each other and then the system relay  6  is turned ON (activated). 
     Further, in response to the final short-time push (step S 5 ), the cipher codes are compared with each other and then cranking (starting of the engine  70 ) is performed. 
     In addition, if the switch  31  is actuated through a long-time push (step S 7 ) after activation of the system relay  6 , the control circuit  22  compares the cipher codes with each other in response and then turns the system relay  6  OFF. 
     On the other hand, as shown in  FIG. 6 , if the switch  31  is actuated through a long-time push (step S 4 ) with the system being OFF and the steering being locked, the control circuit  22  compares the cipher codes with each other and then activates the system relay  6 , performs the unlocking operation of the steering unlocking section  52 , and carries out cranking (starting of the engine  70 ) almost simultaneously. 
     In this case, since the processing of comparing cipher codes with each other in the on-vehicle equipment  2  is performed only once through a long-time push (step S 4 ), the time required for a shift to the starting mode can be reduced. 
     Hereinbelow, a description will be given of countermeasures against tampering. When the switch  31  in  FIG. 1 ,  FIG. 2 , and  FIG. 4  is successively actuated by a malicious third party even if the third party does not possess the portable equipment  1 , the on-vehicle equipment  2  transmits radio waves to communicate with the portable equipment  1 , without performing any specific control, every time the switch  31  is actuated. At this time, the control circuit  22  of the on-vehicle equipment  2  includes actuation signal refusing section  22   a  (refer to  FIGS. 1 and 2 ) described below, which is used for preventing tampering. 
       FIG. 7  is a time chart for explaining the actuation signal refusing section  22   a , in which the lines denoted by reference symbols a, b, c, d, and e each show actuation of an activation switch, an activation switch monitoring period, how radio waves are transmitted from the on-vehicle equipment side, and an interface circuit current of the switch  31 , respectively. The line denoted by reference symbol a indicates an actuation signal of the switch  31 , in particular, an input signal from the switch  31 , which is on the ON side when the switch  31  is pushed. When the switch  31  is pushed, radio waves are transmitted from the on-vehicle equipment  2  side as indicated by the line denoted by reference symbol d, and the interface circuit  22   b  (refer to  FIGS. 1 and 2 ) in the control circuit  22  for the switch  31  consumes a current.  FIG. 7  shows a case where the switch  31  is successively (repeatedly) pushed as indicated by the line denoted by reference symbol a. 
     During the activation switch monitoring period Tb 1 , the actuation signal refusing section  22   a  of the control circuit  22  counts the number of actuation signals, of the actuation signals transmitted from the switch  31 , for each of which no answer signal is obtained from the portable equipment  1  with respect to the inquiry signal transmitted to the portable equipment  1  within a predetermined time period. In other words, the actuation signal refusing section  22   a  counts the number of the actuation signals a from the switch  31 . Then, in a case where the number of the actuation signals a for each of which no answer signal is obtained is equal to or more than a prescribed number of times (for example, 10 times) preset within the monitoring period Tb 1  (for example, 5 to 10 seconds: a first predetermined period), it is determined that the switch  31  is being tampered, and no answer is given to an actuation signal a from the switch  31  for an activation switch actuation lock period Tc 1  (for example, 10 seconds to 1 minute: a third predetermined period), to thereby prevent radio waves from being transmitted to the portable equipment  1 . After that, as indicated by reference symbol al, when an authorized user comes to possess the portable equipment  1  and the switch  31  is actuated by the user, an answer signal is received in response to an inquiry signal transmitted, and normal communication is established with respect to the portable equipment  1  and collation is performed on signals. 
       FIG. 8  is also a time chart for explaining the countermeasures against tampering, in which reference symbols a to e denote constituent elements similar to those of  FIG. 7 . As indicated by the line denoted by reference symbol a of  FIG. 8 , even in a case where the switch  31  is continuously pushed, the interface circuit  22   b  on the on-vehicle equipment side  2  consumes a current as indicated by the line denoted by reference symbol e. Accordingly, in the case where the switch  31  is continuously pushed generating an actuation signal a, the actuation signal refusing section  22   a  measures the duration of time during which no answer signal is obtained from the portable equipment  1  even if an inquiry signal is transmitted to the portable equipment  1  in response to the actuation signal a thus generated. In a case where the duration of time thus measured continues for the activation switch monitoring period Tb 2  (for example, 10 seconds or more: a second predetermined time period) or more (in other words, the actuation signal is kept turned ON for the monitoring period Tb 2  or more), no answer signal is given to the actuation signal a from the switch  31  during the activation switch actuation lock period Tc 1  as described above, to thereby prevent radio waves from being output to the portable equipment  1 . 
     It is also possible to combine the above-mentioned time charts, and in at least one of the cases where actuation signals a for each of which no answer signal are successively obtained prescribed times or more, the prescribed times being predetermined within the monitoring period Tb 1 , and where the actuation signal a for which no answer signal is obtained is kept turned ON for the monitoring period Tb 2  or more, the actuation signal a from the switch  31  may not be responded during the activation switch actuation lock period Tc 1 . The monitoring period Tb 1  and the monitoring period Tb 2  may be set to have different lengths, or have the same length. The number of times of actuation of the switch  31  within the monitoring period Tb 1  is equally counted regardless of whether the switch  31  is pushed for a short time or for a long time. 
     Also, in order not to respond to the actuation signal a from the switch  31 , during the activation switch actuation lock period Tc 1  the interface circuit  22   b  for the switch  31  in the control circuit  22  may be turned into a nonresponding state, that is, an OFF state in which no current flows therethrough. In this manner, power consumption in the interface circuit  22   b  can be reduced. The same applies to a modification embodiment described later. 
     Further, by assuming a case where the above-mentioned successive actuation of the switch  31  shown in  FIG. 7  is repeatedly performed, a plurality of activation switch monitoring periods Tb 1  are provided as shown in  FIG. 9 . In a case where the number of actuation signals an equal to or more than a prescribed times is counted twice or more, it is determined that the switch  31  is still being tampered. In this case, an activation switch actuation lock period Tc 2  (of, for example, 1 minute to 10 minutes) longer than the activation switch actuation lock period Tc 1  which is originally set may be provided so as not to respond to the actuation signal a. The second activation switch monitoring period Tb 1  is started on condition that the switch  31  is actuated within a time T after the expiration of the first activation switch actuation lock period Tc 1  and an actuation signal a for which no answer signal is obtained is input. When the switch  31  is actuated after a lapse of the time T, the flow returns to the start of the first activation switch monitoring period Tb 1 . After that, as indicated by reference symbol al, when an authenticated user comes to possess the portable equipment  1  and the switch  31  is actuated, an answer signal is received in response to an inquiry signal transmitted, and normal communication is established with respect to the portable equipment  1  and collation is performed on signals. 
     Alternatively, by assuming a case where the above-mentioned continuous actuation of the switch  31  shown in  FIG. 8  is repeatedly performed, a plurality of activation switch monitoring periods Tb 2  are provided as shown in  FIG. 10 . In a case where two or more of the actuation signals a which are kept turned on for the monitoring period Tb 2  or more are counted, it is determined that the switch  31  is still being tampered. In this case, an activation switch actuation lock period Tc 2  (of, for example, 1 minute to 10 minutes) longer than the activation switch actuation lock period Tc 1  which is originally set may be provided so as not to respond to the actuation signal a. The second activation switch monitoring period Tb 2  is started on condition that the switch  31  is actuated within a time T after the expiration of the first activation switch actuation lock period Tc 1  and an actuation signal a for which no answer signal is obtained is input. When the switch  31  is actuated after a lapse of the time T, the flow returns to the start of the first activation switch monitoring period Tb 2 . After that, as indicated by reference symbol al, when an authenticated user comes to possess the portable equipment  1  and the switch  31  is actuated, an answer signal is received in response to an inquiry signal transmitted, and normal communication is established with respect to the portable equipment  1  and collation is performed on signals. 
     The functions described in  FIG. 9  and  FIG. 10  may be selectively provided in addition to the functions shown in  FIG. 7  and  FIG. 8  as necessary. 
     Also, in the above description, the activation switch actuation lock periods Tc 1  and Tc 2  are provided in twofold. The activation switch actuation lock periods, however, may also be provided in threefold or more, and the duration of each of the activation switch actuation lock periods may be increased stepwise along with the increase in the number of times of occurrence of the above-mentioned status. 
     Also, the above-mentioned function or construction is not limited to the above-mentioned system, and may also be applicable to a key system used for a glove compartment or a tank cap of a two-wheeled vehicle, which uses an electric key system which is unlocked through the above-mentioned switch actuation. 
     As described above, according to the present invention, it is possible to suppress wasteful consumption of a battery due to an unnecessary operation of an activation switch tampered by a third party and also to prevent the components from being degraded due to overheating of the control circuit. 
     In particular, in a case where the present invention is applied to a two-wheeled vehicle, for which a cost reduction is demanded, the present invention produces a significant effect of preventing, at low cost, a battery from being consumed due to tampering, without additionally providing hardware. 
     In the above, the description has been given of a case where the present invention is applied to a two-wheeled vehicle, but it is of course possible to apply the present invention to another arbitrary propelled object which is propelled by the engine  70  (for example, an automobile, an ATV, a ship, a jet-propulsion watercraft, or the like).

Technology Category: b