JP2017007589A - Occupant protection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure size reduction and weight reduction, and to continue the activation of an occupant protection device even if the supply of power from a battery via an ignition switch is interrupted.SOLUTION: An occupant protection device 10 has: an activation part 12 which switches a switch part Q to a conduction state when a supply voltage E1 which is supplied to a first power supply line L1 from a battery BAT via an ignition switch IGSW is not lower than a voltage threshold; a second power supply line L2 which connects the battery BAT and a power supply part 17 not via the ignition switch IGSW but via the switch part Q; and a vehicle speed reflection part 15 which switches the switch part Q to the conduction state by a calculation value which is obtained by using acceleration detected by an acceleration sensor 16. Since it is not necessary to install a power accumulation part, size reduction and weight reduction can be secured. Even if the supply of power from the battery BAT via the ignition switch IGSW is interrupted, the activation of an occupant protection device 11 can be continued.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an occupant protection system including an occupant protection device, an acceleration sensor, a control unit, a switch unit, and a power supply unit.

  Conventionally, an example of a technique related to a vehicle occupant protection system for enabling operation even when power supply from a battery or the like is cut off due to an unexpected failure has been disclosed (for example, Patent Document 1). See). This vehicle occupant protection system detects a safety device, a power storage unit, a bypass line that connects the front of the acceleration sensor unit on the first branch line, a switching unit that opens and closes the bypass line, and a voltage of the power line And a switch control unit that closes the switching unit when the voltage detected by the power supply voltage monitoring unit is equal to or lower than a predetermined threshold value.

JP 2013-199145 A

  However, the technique described in Patent Document 1 requires a power storage unit. Since this power storage unit is used as a power source for determining a collision while the vehicle is traveling and for starting a safety device (corresponding to an occupant protection device), it has to have a large capacity. Therefore, there is a problem that the power storage unit becomes large and hinders reduction in size and weight of the passenger protection system.

  On the other hand, when the power storage unit is not provided, when the supply of power is cut off from the battery via the ignition switch, information about the vehicle (for example, the speed of the vehicle) cannot be acquired from the external device. For this reason, it is impossible to determine whether the vehicle is running or stopped, and there is a problem that it is not possible to determine whether or not the activation of the occupant protection device should be continued.

  The present invention has been made in view of the above points, and while ensuring a reduction in size and weight, an occupant capable of continuing the activation of the occupant protection device even when the supply of power is cut off from the battery via the ignition switch. The purpose is to provide a protection system.

The invention made in order to solve the above problems includes an occupant protection device (11) for protecting an occupant of a vehicle (C), an acceleration sensor (16) for detecting acceleration (a) of the vehicle, and the acceleration sensor. A control unit (13) that controls the operation of the occupant protection device based on the detected acceleration, and is interposed between the battery (BAT) and the power supply unit (17), and can be switched between a conductive state and a non-conductive state. An occupant protection system including a switch unit (Q) and at least the power supply unit that converts electric power supplied from the battery via the switch unit and outputs the converted power to the occupant protection device, the acceleration sensor, and the control unit In (10),
Depending on whether or not the supply voltage (E1) supplied from the battery to the first power supply line (L1) through the ignition switch (IGSW) is equal to or higher than the voltage threshold (Eth), the switch unit is turned on or off. An activation unit (12) for switching to any one of the states, and a second power supply line (L2) for electrically connecting the battery and the power supply unit via the switch unit without using the ignition switch And a vehicle speed reflecting unit (15) for switching the switch unit to either a conductive state or a non-conductive state based on a calculation value calculated using acceleration detected by the acceleration sensor.

  According to this configuration, in an abnormal state, power supply from the battery is cut off via the ignition switch, and the supply voltage supplied to the first power supply line becomes less than the voltage threshold. Therefore, the switch unit is switched to the conductive state by the control of the control unit and the vehicle speed reflecting unit. Therefore, the electric power supplied from the battery is output to the occupant protection device, the acceleration sensor, the control unit, and the like via the power supply unit. Since there is no need to provide a power storage unit, it is possible to ensure miniaturization and weight reduction. In addition, even when the supply of power from the battery is cut off via the ignition switch, the switch unit is switched to the conductive state, so that the activation of the occupant protection device can be continued.

  In a normal state (also referred to as a normal state), power is supplied from the battery via the ignition switch, and the supply voltage supplied to the first power supply line is equal to or higher than the voltage threshold. Therefore, the switch unit is switched to the conductive state under the control of the control unit and the activation unit. Therefore, the electric power supplied from the battery is output to the occupant protection device, the acceleration sensor, the control unit, and the like via the power supply unit. Therefore, the activation of the occupant protection device can be reliably continued even in the normal state.

  The “vehicle” may be any number of wheels or a power engine. As the “occupant protection device”, any device may be applied as long as it can protect the occupant, and examples thereof include an airbag and a seat belt pretensioner. The “switch unit” may be any element or component that can be switched between a conductive state and a non-conductive state by an activation unit, a vehicle speed reflecting unit, or the like. For example, a transistor, a relay, etc. correspond. The “ignition switch” is arbitrary as long as it is a switch for switching whether or not power is supplied from the battery for traveling of the vehicle or the like, regardless of whether or not a mechanical key is used. The “battery” is arbitrary regardless of the type as long as it can supply electric power for operating the occupant protection device. “Activation” of the occupant protection device means a state in which the occupant protection device can be activated when acceleration exceeding an allowable value due to a collision or the like is detected.

It is a mimetic diagram showing the example of composition of vehicles. It is a block diagram which shows the 1st structural example of a passenger | crew protection system. It is a block diagram which shows the structural example of a passenger | crew protection apparatus. It is a schematic diagram which shows the conditions which enable starting a passenger | crew protection apparatus. It is a flowchart figure which shows the example of a procedure of a passenger | crew protection apparatus starting process. It is a flowchart figure which shows the example of a procedure of a vehicle speed reflection process. It is a flowchart figure which shows the example of a procedure of the deceleration period determination process. It is a flowchart figure which shows the example of a procedure of a low speed period determination process. It is a time chart figure which shows the 1st example which enables starting of a passenger protection device. It is a time chart figure which shows the 2nd example which enables starting of a passenger | crew protection apparatus. It is a time chart figure which shows the 3rd example which enables starting of a passenger | crew protection apparatus. It is a time chart figure which shows the 4th example which enables starting of a crew member protection device. It is a time chart figure showing the 5th example which enables starting of a crew member protection device. It is a time chart figure showing the 6th example which enables starting of a crew member protection device. It is a block diagram which shows partially the 2nd structural example of a passenger | crew protection system. It is a schematic diagram which shows the example which makes a 2nd power supply line a redundant structure.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. Note that unless otherwise specified, “connecting” means electrically connecting. Each figure shows elements necessary for explaining the present invention, and does not necessarily show all actual elements. When referring to directions such as up, down, left and right, the description in the drawings is used as a reference. In each figure, the same elements are denoted by the same reference numerals. Hereinafter, “vehicle speed” is simply referred to as “vehicle speed”. For the vehicle speed and acceleration, a parameter “(t)” is attached to a value that changes over time. The “running” of the vehicle includes a short-term pause according to signals, signs, and the like. In this embodiment, positive logic is applied as ON / OFF.

  A vehicle C shown in FIG. 1 is a four-wheeled vehicle having a battery BAT, an ignition switch IGSW, an airbag 11a, a seat belt pretensioner 11b, an acceleration sensor 16, and the like. The power engine of the vehicle C does not matter. The battery BAT is an electric power source that supplies electric power necessary for traveling the vehicle C, operating the occupant protection device 11, and the like. The battery BAT is arbitrary as long as it is a power source capable of supplying power, and for example, a secondary battery, a fuel cell, a solar cell, or the like is applicable. The secondary battery corresponds to, for example, a lithium ion battery, a chemical battery such as a lead storage battery or a nickel cadmium storage battery.

  The ignition switch IGSW is a switch for switching whether to supply power from the battery BAT, and does not matter the installation position in the vehicle C. For example, the position illustrated with a solid line may be sufficient as the position illustrated with a dashed-two dotted line. In the present embodiment, an example in which the battery BAT supplies the vehicle to the occupant protection system 10 (specifically, the power supply unit 17) via the ignition switch IGSW as shown in FIG. It supplies also to the other apparatus provided. The airbag 11a is provided around a seat (for example, a driver seat or a passenger seat) and operates in an emergency to protect an occupant. The seat belt pretensioner 11b is connected to a seat belt (not shown) and operates in an emergency to protect the occupant. One or more airbags 11a and seat belt pretensioners 11b may be installed. The acceleration sensor 16 detects the acceleration a of the vehicle C.

  The occupant protection system 10 shown in FIG. 2 includes an occupant protection device 11, an activation unit 12, a control unit 13, a communication unit 14, a vehicle speed reflection unit 15, an acceleration sensor 16, a power supply unit 17, a switch unit Q, a first power line L1, A second power supply line L2 and the like are included. The elements other than the occupant protection device 11 may be arranged or configured arbitrarily, and may be provided independently of each other, or a plurality of elements may be integrated. Since there is no need to provide a power storage unit, it is possible to ensure miniaturization and weight reduction.

  A configuration example of the occupant protection device 11 will be described with reference to FIG. 3 includes an airbag 11a, a seat belt pretensioner 11b, an ignition unit 11c, a drive unit 11d, and the like. The airbag 11a and the seat belt pretensioner 11b are members that protect the passengers of the vehicle C. When the control signal SE is transmitted from the control unit 13 to the ignition unit 11c, the airbag 11a is deployed to protect the occupant. The ignition unit 11c includes, for example, a squib that performs ignition. When the control signal SF is transmitted from the control unit 13 to the drive unit 11d, the seat belt pretensioner 11b operates the seat belt (including expansion and contraction and holding) to protect the occupant. The drive unit 11d includes, for example, a motor and a squib.

  Returning to FIG. 2, the first power supply line L1 and the second power supply line L2 are each a conductive line, a cable, or the like for sending the power of the battery BAT. The starting unit 12, the control unit 13, the communication unit 14, and the vehicle speed reflecting unit 15 may all have a software configuration or a hardware configuration. The software configuration is a configuration in which the function of each unit is realized by the CPU executing a program. The hardware configuration is a configuration in which functions of each unit are realized by hardware logic including an electronic circuit and a logic circuit. The power supply unit 17 converts the power supplied from the battery BAT and outputs it to the occupant protection device 11, the starter unit 12, the control unit 13, the communication unit 14, the vehicle speed reflecting unit 15, the acceleration sensor 16, and the like.

  The control unit 13 controls the entire occupant protection system 10. The control unit 13 includes control for monitoring the supply voltage E1 supplied from the battery BAT to the first power supply line L1 via the ignition switch IGSW. The control unit 13 includes control for transmitting the control signal SB to the starting unit 12 and transmitting the control signal SD to the vehicle speed reflecting unit 15. The control unit 13 calculates the vehicle speed V (that is, the speed of the vehicle C) based on the acceleration a transmitted from the acceleration sensor 16, or activates the occupant protection device 11 when the acceleration a changes to an acceleration threshold value ath or more due to a collision or the like. Includes control to activate. The control unit 13 includes control for transmitting and receiving information to and from the external device 20 via the communication unit 14. Transmission and reception may be wired or wireless. The external device 20 that is communicably connected to the occupant protection system 10 corresponds to, for example, one or more ECUs (Electronic Control Units), one or more computers, and may include a communication network provided in the vehicle C.

  The switch part Q is interposed between the battery BAT and the power supply part 17. When the switch unit Q is in a conductive state (for example, an on state), the power of the battery BAT is supplied to the power source unit 17. On the other hand, when the switch unit Q is in a non-conduction state (for example, an off state), the power of the battery BAT is not supplied to the power source unit 17. In this embodiment, a transistor is applied as the switch unit Q. The type of the transistor is arbitrary, but, for example, FET or IGBT is applicable.

  The activation unit 12 transmits a control signal SA to the switch unit Q (for example, a control terminal such as a gate terminal or a base terminal), and switches the switch unit Q to either the conductive state or the non-conductive state. The vehicle speed reflecting unit 15 transmits the control signal SC to the switch unit Q, and switches the switch unit Q to either the conductive state or the non-conductive state. The control signal SA and the control signal SC are logically summed and transmitted to the switch unit Q.

  The control unit 13 performs necessary control based on whether or not a predetermined condition is satisfied. The predetermined condition may be arbitrarily set, and includes, for example, a vehicle speed condition, a speed non-acquisition condition, a deceleration period condition, a low speed period condition, and the like. The vehicle speed condition is a condition for determining whether or not the vehicle speed V (t) is equal to or higher than the speed threshold Vth (see also step S31 in FIG. 6 described later).

  The speed non-acquisition condition is a condition in which the current vehicle speed Vo cannot be acquired from the external device 20 via the communication unit 14. Specifically, the case where the power supply is not received from the battery BAT and the supply voltage E1 is less than the voltage threshold Eth (E1 <Eth) and the case where the vehicle speed Vo is not transmitted from the external device 20 are applicable.

  The deceleration period condition is a condition for determining whether or not the deceleration period TD is shorter than the allowable deceleration period TDth (see also step S43 in FIG. 7 described later). The deceleration period TD is a period in which the vehicle speed V is equal to or lower than the speed threshold Vth and continuously decreases.

  The low speed period condition is a condition for determining whether or not the low speed period TL is shorter than the low speed allowable period TLth (see also step S53 in FIG. 8 described later). The low speed period TL is a period during which the vehicle speed V (t) continues to be equal to or lower than the speed threshold Vth.

  Any of the allowable deceleration period TDth and the allowable low speed period TLth described above may be set to any length, for example, 30 [sec] or 2 [min]. The magnitude relationship between the allowable deceleration period TDth and the allowable low speed period TLth may also be set arbitrarily. That is, TDth> TLth may be set, TDth = TLth may be set, or TDth <TLth may be set.

  When the ignition switch IGSW is ON while the vehicle C is traveling and the supply voltage E1 is equal to or higher than the voltage threshold Eth (E1 ≧ Eth), the control unit 13 transmits the ON control signal SB to the starting unit 12. Upon receiving the ON control signal SB, the activation unit 12 switches the switch unit Q to the conductive state or continues with the ON control signal SA. In the normal state, since the power of the battery BAT is supplied to the power supply unit 17, the occupant protection device 11 can be activated.

  On the other hand, when an abnormal state occurs during the traveling of the vehicle C and the supply voltage E1 becomes less than the voltage threshold Eth (E1 <Eth), does the control unit 13 transmit the OFF control signal SB to the starting unit 12? , ON control signal SB is not transmitted. The abnormal state corresponds to, for example, the ignition switch IGSW being turned off, a failure (for example, disconnection or short circuit) in the first power supply line L1, or an abnormality in the battery BAT itself. In short, a state in which the supply of electric power is cut off from the battery BAT via the ignition switch IGSW during traveling of the vehicle C is applicable. The activation unit 12 that has received the OFF control signal SB or no longer receives the ON control signal SB causes the switch unit Q to be in a non-conductive state by the OFF control signal SA. If the switch part Q becomes a non-conduction state in an abnormal state, the power of the battery BAT is not supplied to the power supply part 17 and the occupant protection device 11 cannot be activated.

  Therefore, the control unit 13 performs control so as to maintain a state where the occupant protection device 11 can be activated if the vehicle speed condition, the speed non-acquisition condition, the deceleration period condition, and the low speed period condition are satisfied. The time when the supply voltage E1 becomes less than the voltage threshold Eth is set as a reference time STD. As the start of the deceleration period TD included in the deceleration period condition, a later time is applied between the reference time STD and the start of the deceleration period TD. The start time of the low speed period TL included in the low speed period condition is a later time of the reference time STD and the start time of the low speed period TL. When applied in this manner, it is possible to reliably ensure the deceleration allowable period TDth and the low speed allowable period TLth and maintain a state where the occupant protection device 11 can be activated.

  Specifically, the control unit 13 transmits an ON control signal SD to the vehicle speed reflecting unit 15 if any one of the vehicle speed condition, the speed non-acquisition condition, the deceleration period condition, and the low speed period condition is satisfied. The vehicle speed reflecting unit 15 that has received the ON control signal SD switches the switch unit Q to the conductive state or continues by the ON control signal SC.

  On the other hand, if the vehicle speed condition or the speed non-acquisition condition is not satisfied and either the deceleration period condition or the low speed period condition is not satisfied, the control unit 13 sends an OFF control signal SD to the vehicle speed reflection unit 15. It is transmitted or the ON control signal SD is not transmitted. The vehicle speed reflecting unit 15 that has received the OFF control signal SD or no longer receives the ON control signal SD makes the switch unit Q non-conductive by the OFF control signal SC. When the switch part Q becomes a non-conduction state, the power of the battery BAT is not supplied to the power supply part 17, and the function of the entire occupant protection system 10 is stopped.

  The control part 13 mentioned above performs control which maintains the state which can start the passenger | crew protection apparatus 11 like the logic diagram shown in FIG. That is, the switch unit Q is turned on, and the power of the battery BAT is supplied to the power source unit 17. Case (a) corresponds to a state where the ignition switch IGSW is ON and the supply voltage E1 is equal to or higher than the voltage threshold Eth. Case (b) and case (c) are based on the assumption that the ignition switch IGSW is OFF (or the first power supply line L1 is disconnected, etc.). Case (b) corresponds to a state where the current vehicle speed V (t) exceeds the speed threshold Vth. Case (c) is a state in which the current vehicle speed V (t) is not more than the speed threshold value Vth, and the deceleration period condition and the low speed period condition are satisfied. That is, the deceleration period TD is shorter than the allowable deceleration period TDth (TD <TDth), or the low speed period TL is shorter than the allowable low speed period TLth (TL <TLth).

  An example of control executed by the control unit 13 will be described with reference to flowcharts shown in FIGS. The occupant protection device activation process shown in FIG. 5 is executed on the assumption that the ignition switch IGSW is turned from OFF to ON in a stopped vehicle.

  In the occupant protection device activation process of FIG. 5, it is first determined whether or not the supply voltage E1 of the first power supply line L1 is equal to or higher than the voltage threshold Eth [step S10]. If the supply voltage E1 is lower than the voltage threshold Eth (E1 <Eth; NO in step S10), the ignition switch IGSW is OFF and the vehicle C does not travel, so it waits.

  Thereafter, if the supply voltage E1 becomes equal to or higher than the voltage threshold Eth (E1 ≧ Eth; YES in step S10), it indicates that the ignition switch IGSW is turned on. Therefore, the control unit 13 transmits the ON control signal SB to the activation unit 12, and the activation unit 12 transmits the ON control signal SA to the switch unit Q to switch to the conductive state [Step S11]. When the switch part Q becomes conductive, electric power is supplied from the battery BAT to the power supply part 17, and the occupant protection device 11 can be activated [step S12].

  The control unit 13 acquires the current vehicle speed Vo from the external device 20 via the communication unit 14 [step S13]. It does not matter how the vehicle speed Vo is acquired. The vehicle speed Vo may be acquired within a predetermined period FT from a reference time STD described later, and is preferably immediately before the reference time STD. The length of the predetermined period FT may be arbitrarily set, and an average value or the like may be used when a plurality of vehicle speeds Vo are acquired within the predetermined period FT. When the vehicle speed Vo is not transmitted from the external device 20 included in the speed non-acquisition condition, the acceleration a transmitted from the acceleration sensor 16 is calculated to obtain the calculated vehicle speed Vo.

  If the supply voltage E1 is equal to or higher than the voltage threshold Eth during traveling of the vehicle C (E1 ≧ Eth; YES in Step S14), the control unit 13 continues to transmit the ON control signal SB to the starting unit 12. Therefore, the starting unit 12 transmits the ON control signal SA to the switch unit Q and continues the conduction state [step S15]. Since the switch part Q continues to be in a conductive state, power is continuously supplied from the battery BAT to the power supply part 17 and the state in which the occupant protection device 11 can be started continues.

  On the other hand, when the supply voltage E1 becomes less than the voltage threshold Eth during traveling of the vehicle C (E1 <Eth; NO in step S14), the control unit 13 determines that an abnormal state has occurred. The occurrence time of the abnormal state is set as a reference time STD. Since the vehicle speed Vo cannot be acquired from the external device 20, the speed non-acquisition condition is satisfied. The control unit 13 transmits the ON control signal SD to the vehicle speed reflecting unit 15, and the vehicle speed reflecting unit 15 transmits the ON control signal SC to the switch unit Q and continues the conduction state [step S20]. As shown in parentheses in step S20, an OFF control signal SB may be transmitted to the activation unit 12, and the activation unit 12 may transmit an OFF control signal SA to the switch unit Q so as to be in a non-conductive state. . Since the conduction state of the switch unit Q is continued by the vehicle speed reflecting unit 15, power is continuously supplied from the battery BAT to the power source unit 17, and the state where the occupant protection device 11 can be started is also continued.

  In the abnormal state, the current vehicle speed Vo cannot be acquired from the external device 20 via the communication unit 14, so the control unit 13 acquires the acceleration a (t) from the acceleration sensor 16 in order to estimate the current vehicle C [ Step S21], the vehicle speed reflection process shown in FIG. 6 is executed [Step S22].

  In the vehicle speed reflection process of FIG. 6, the current vehicle speed V (t) is estimated by calculation using the acceleration a (t) acquired in step S21 [step S30]. The vehicle speed V (t) corresponds to the calculated value. The estimated vehicle speed V (t) is recorded in the recording medium 13a and used as the previous vehicle speed V (t-1) in estimating the next vehicle speed V (t). An arithmetic expression for obtaining the vehicle speed V (t) is the following expression M1, and a vehicle speed V (0) that is an initial value of the vehicle speed V (t) is an expression M2.

  Formula M1 adds the value obtained by integrating the acceleration a (t) in the period from time (t-1) to time t to the previously calculated vehicle speed V (t-1), so that the current vehicle speed V ( t) can be determined. A period from time (t−1) to time t corresponds to a “sampling period”, and an arbitrary length (for example, 10 [msec] or 100 [msec]) may be set. Expression M2 sets the vehicle speed Vo acquired in step S13 of FIG. 5 as the vehicle speed V (0). By setting in this way, the accuracy of the vehicle speed V (t) after the occurrence of an abnormal state is increased.

  Then, the process branches depending on whether or not the vehicle speed condition is satisfied [step S31]. The vehicle speed condition is a condition that, for example, the vehicle speed V (t) obtained in step S30 is larger than the speed threshold value Vth. The speed threshold Vth may be arbitrarily set, and corresponds to 10 [Km / h], 16 [Km / h], or the like, for example. If the vehicle speed V (t) is larger than the speed threshold Vth (V (t)> Vth; YES in step S31), the control unit 13 continuously transmits the ON control signal SD to the vehicle speed reflection unit 15, The vehicle speed reflecting unit 15 continuously transmits the ON control signal SC to the switch unit Q and continues the conduction state [step S32]. Therefore, power is continuously supplied from the battery BAT to the power supply unit 17, and the state in which the occupant protection device 11 can be started continues. Thereafter, the vehicle speed reflection process is returned, and the process returns to step S13 shown in FIG.

  On the other hand, if the vehicle speed V (t) is equal to or less than the speed threshold Vth (V (t) ≦ Vth; NO in step S31), the deceleration period determination process shown in FIG. 7 and [step S33], the low speed period determination shown in FIG. The process is executed [step S34]. The deceleration period determination process and the low speed period determination process are not limited to the order shown in FIG. 6, and may be executed in any order or in parallel. Thereafter, the vehicle speed reflection process is returned, and the process returns to step S13 of the occupant protection device activation process shown in FIG. Hereinafter, an example of the deceleration period determination process and the low speed period determination process will be described.

  In the deceleration period determination process of FIG. 7, the process branches depending on whether or not the vehicle C is decelerating [step S40]. For example, it is determined whether or not the current vehicle speed V (t) obtained in step S30 in FIG. 6 is smaller than the previous vehicle speed V (t-1). As shown in parentheses in step S40, the determination may be made based on whether or not the acceleration a (t) acquired in step S21 in FIG. 5 is a negative value.

  In step S40, if the vehicle C is decelerating (V (t) <V (t-1) or a (t) <0; YES), the process branches according to the state of the deceleration period flag TDF [step S41]. The deceleration period flag TDF is a flag indicating whether or not the vehicle speed V continuously decreases. The deceleration period flag TDF is ON as long as the vehicle C continues to decelerate, and is OFF when the vehicle C is not decelerating (that is, acceleration or constant speed).

  If the deceleration period flag TDF is ON in step S41 (YES), the deceleration period TD is increased [step S42]. The deceleration period TD is a period during which the vehicle speed V continuously decreases, and is obtained by calculating TD = TD + Ts. The deceleration period TD on the left side is the deceleration period TD that is required this time. The deceleration period TD on the right side is a value obtained last time and recorded on the recording medium 13a. The sampling time Ts on the right side is the period from time (t-1) to time t described above. That is, as long as the deceleration period flag TDF remains ON, the deceleration period TD increases by the sampling time Ts.

  Then, the process branches depending on whether or not the deceleration period condition is satisfied [step S43]. The deceleration period condition is, for example, a condition that the deceleration period TD is shorter than the allowable deceleration period TDth.

  In step S43, if the deceleration period TD is shorter than the allowable deceleration period TDth (TD <TDth; YES), power is continuously supplied from the battery BAT to the power supply unit 17, and the passenger protection device 11 can be started. . Specifically, the control signal SD transmitted from the control unit 13 to the vehicle speed reflecting unit 15 and the control signal SC transmitted from the vehicle speed reflecting unit 15 to the switch unit Q are continuously turned ON, and the conduction state of the switch unit Q is continued. [Step S48]. Thereafter, the deceleration period determination process is returned to return to the vehicle speed reflection process of FIG.

  If the vehicle C is not decelerating in step S40 (V (t) ≧ V (t−1) or a (t) ≧ 0; NO), the deceleration period flag TDF is turned OFF [step S47]. Since vehicle C is not decelerating, step S48 is executed in order to continue supplying power from battery BAT to power supply unit 17 so that occupant protection device 11 can be activated. Thereafter, the deceleration period determination process is returned to return to the vehicle speed reflection process of FIG.

  Furthermore, if the deceleration period flag TDF is OFF in step S41 (NO), the vehicle C starts to decelerate, so the deceleration period flag TDF is turned on [step S45] and the deceleration period TD is initialized to 0 [ Step S46]. Since vehicle C has just started to decelerate, step S48 is executed in order to continue supplying power from battery BAT to power supply unit 17 so that occupant protection device 11 can be activated. Thereafter, the deceleration period determination process is returned to return to the vehicle speed reflection process of FIG.

  On the other hand, if the deceleration period TD is equal to or greater than the allowable deceleration period TDth in step S43 (TD ≧ TDth; NO), the control unit 13 transmits the OFF control signal SD to the vehicle speed reflecting unit 15 and the vehicle speed reflecting unit 15 Transmits the OFF control signal SC to the switch part Q to turn it off (step S44). Therefore, power is not supplied from the battery BAT to the power supply unit 17, and the function of the entire occupant protection system 10 is stopped. By limiting the time when the occupant protection device 11 can be activated until the deceleration period TD passes the deceleration allowable period TDth, power consumption of the battery BAT can be suppressed.

  In the low speed period determination process of FIG. 8, the process branches depending on whether or not the vehicle C is traveling at a vehicle speed V (t) equal to or lower than the speed threshold Vth [step S50]. For example, the determination is made based on whether or not the current vehicle speed V (t) obtained in step S30 in FIG.

  In step S50, if the vehicle C is traveling below the speed threshold Vth (V (t) ≦ Vth; YES), the process branches depending on the state of the low speed period flag TLF [step S51]. The low speed period flag TLF is a flag indicating whether or not the vehicle speed V is continuously running at a low speed. The low speed period flag TLF is ON as long as the vehicle C is traveling at a low speed equal to or less than the speed threshold Vth, and is OFF when the vehicle C travels exceeding the speed threshold Vth.

  If the low speed period flag TLF is ON in step S51 (YES), the low speed period TL is increased [step S52]. The low speed period TL is a period during which the vehicle speed V continuously decreases, and is obtained by calculating TL = TL + Ts. The low speed period TL on the left side is the low speed period TL to be obtained this time. The low speed period TL on the right side is a value obtained last time and recorded on the recording medium 13a. The sampling time Ts on the right side is the period from time (t-1) to time t described above. That is, as long as the low speed period flag TLF remains ON, the low speed period TL increases by the sampling time Ts.

  Then, the process branches depending on whether the low speed period condition is satisfied [step S53]. The low speed period condition is, for example, a condition that the low speed period TL is shorter than the low speed allowable period TLth. The low speed allowable period TLth may be set to an arbitrary length in the same manner as the deceleration allowable period TDth.

  In step S53, if the low speed period TL is shorter than the low speed allowable period TLth (TL <TLth; YES), power is continuously supplied from the battery BAT to the power supply unit 17, and the passenger protection device 11 can be activated. . Specifically, the control signal SD transmitted from the control unit 13 to the vehicle speed reflecting unit 15 and the control signal SC transmitted from the vehicle speed reflecting unit 15 to the switch unit Q are continuously turned ON, and the conduction state of the switch unit Q is continued. [Step S58]. Thereafter, the low speed period determination process is returned to return to the vehicle speed reflection process of FIG.

  If the vehicle C is traveling at the vehicle speed V (t) exceeding the speed threshold Vth in step S50 (V (t)> Vth; NO), the low speed period flag TLF is turned off [step S57]. Since the vehicle C is not traveling at a low speed, the power supply unit 17 is continuously supplied with power from the battery BAT, and step S58 is executed in order to continue the state in which the occupant protection device 11 can be activated. Thereafter, the low speed period determination process is returned to return to the vehicle speed reflection process of FIG.

  Further, if the low speed period flag TLF is OFF in step S51 (NO), the vehicle C starts running at a low speed, so the low speed period flag TLF is turned ON [step S55] and the low speed period TL is initialized to 0. [Step S56]. The time initialized in step S56 is the beginning of the low speed period TL. When the supply voltage E1 becomes less than the voltage threshold Eth in step S14 of FIG. 5, if the vehicle speed V (t) is equal to or lower than the speed threshold Vth in step S50, the start of the low speed period TL becomes the reference time STD. Since vehicle C has just started running at a low speed, step S58 is executed in order to continue supplying power from battery BAT to power supply unit 17 so that occupant protection device 11 can be activated. Thereafter, the low speed period determination process is returned to return to the vehicle speed reflection process of FIG.

  On the other hand, if the low speed period TL becomes equal to or higher than the low speed allowable period TLth in step S53 (TL ≧ TLth; NO), the control unit 13 transmits the OFF control signal SD to the vehicle speed reflection unit 15 and the vehicle speed reflection unit 15 Transmits the OFF control signal SC to the switch part Q to turn it off (step S54). Therefore, power is not supplied from the battery BAT to the power supply unit 17, and the function of the entire occupant protection system 10 is stopped. By limiting the time when the occupant protection device 11 can be activated until the low speed period TL passes the low speed allowable period TLth, the power consumption of the battery BAT can be suppressed.

  FIG. 9 to FIG. 9 show control examples when the above-described occupant protection device activation processing (FIG. 5), vehicle speed reflection processing (FIG. 6), deceleration period determination processing (FIG. 7), and low speed period determination processing (FIG. 8) are executed. This will be described with reference to FIG.

(First example)
The first example shown in FIG. 9 is an example in which the occupant protection device 11 can be activated while the vehicle speed condition and the deceleration period condition are satisfied. However, the relationship between the allowable deceleration period TDth and the allowable low speed period TLth is TDth <TLth.

  While the vehicle C is traveling, the supply voltage E1 of the first power supply line L1 is a voltage Ea that exceeds the voltage threshold Eth until time t13. Therefore, the control unit 13 transmits the ON control signal SB to the activation unit 12, and the activation unit 12 sets the switch unit Q to the conductive state by the ON control signal SA (step S15 in FIG. 5). Since the voltage is lower than the voltage threshold Eth after time t13 (0 [V] in FIG. 9), the control unit 13 transmits the ON control signal SD to the vehicle speed reflecting unit 15, and the vehicle speed reflecting unit 15 controls the ON. The switch portion Q is turned on by the signal SC (step S20 in FIG. 5). The switch unit Q remains conductive after time t13, and the power supply unit 17 is supplied with power of the supply voltage E2 (voltage Eb in FIG. 9) from the battery BAT via the second power supply line L2. Continue to be able to start.

  Until time t <b> 13, the control unit 13 can acquire the vehicle speed Vo from the external device 20 via the communication unit 14. After the time t13, the current vehicle speed V is obtained using the vehicle speed Vo acquired in the predetermined period FT from the time t11 to the time t13 and recorded on the recording medium 13a, and the acceleration a (t) acquired from the acceleration sensor 16. (t) is estimated (step S30 in FIG. 6). Since the vehicle speed V (t) becomes equal to or less than the speed threshold Vth at time t14, the deceleration period TD is counted starting from time t14 (step S42 in FIG. 7), and the low speed period TL is counted (step in FIG. 8). S52).

  After time t14, the vehicle speed V (t) continues to decelerate, and at time t15, the deceleration period TD becomes equal to or longer than the allowable deceleration period TDth (step S43 in FIG. 7). According to the precondition of this example, the low speed period TL is within the low speed allowable period TLth. Since the deceleration period TD is equal to or longer than the allowable deceleration period TDth, the control unit 13 transmits the OFF control signal SD to the vehicle speed reflecting unit 15, and the vehicle speed reflecting unit 15 is in the non-conducting state of the switch unit Q by the OFF control signal SC. (Step S44 in FIG. 7). Therefore, until the time t15, the occupant protection device 11 is continuously activated, and the function of the entire occupant protection system 10 is stopped at the time t15. For example, even if the vehicle C exists on an uphill and temporarily decelerates, and then the vehicle C starts to descend, it is estimated that the vehicle C tends to stop by continuously decelerating. Can do. The vehicle C stopped traveling at time t16 after time t15.

(Second example)
The second example shown in FIG. 10 is an example in which the occupant protection device 11 can be activated while the vehicle speed condition and the low speed period condition are satisfied. As in the first example, the relationship between the allowable deceleration period TDth and the allowable low speed period TLth is TDth <TLth. Until time t14, the description is omitted because it is the same as the first example shown in FIG. 9 described above.

  After time t14, the vehicle speed V (t) remains below the speed threshold Vth, and at time t17, the low speed period TL becomes equal to or higher than the low speed allowable period TLth (step S53 in FIG. 8). However, since the vehicle speed V (t) may increase between time t14 and time t17, the deceleration period TD is within the allowable deceleration period TDth. Since the low speed period TL is equal to or longer than the low speed allowable period TLth, the control unit 13 transmits the OFF control signal SD to the vehicle speed reflecting unit 15, and the vehicle speed reflecting unit 15 is in the non-conducting state of the switch unit Q by the OFF control signal SC. (Step S54 in FIG. 8). Therefore, until the time t15, the occupant protection device 11 is continuously activated, and the function of the entire occupant protection system 10 is stopped at the time t15. The vehicle C stopped traveling at time t18 after time t17.

(Third example)
The third example shown in FIG. 11 is an example in which the occupant protection device 11 can be activated while the vehicle speed condition and the low speed period condition are satisfied. However, the relationship between the allowable deceleration period TDth and the allowable low speed period TLth is TDth> TLth. Until time t14, the description is omitted because it is the same as the first example shown in FIG. 9 and the second example shown in FIG.

  After time t14, the vehicle speed V (t) continues to be equal to or lower than the speed threshold Vth, and at time t20, the low speed period TL becomes equal to or higher than the low speed allowable period TLth (step S53 in FIG. 8). According to the precondition of this example, the deceleration period TD is within the allowable deceleration period TDth from time t14 to time t21. Since the low speed period TL is equal to or longer than the low speed allowable period TLth, the control unit 13 transmits the OFF control signal SD to the vehicle speed reflecting unit 15, and the vehicle speed reflecting unit 15 is in the non-conducting state of the switch unit Q by the OFF control signal SC. (Step S54 in FIG. 8). Therefore, until the time t20, the occupant protection device 11 is continuously activated, and the function of the entire occupant protection system 10 is stopped at the time t20. The vehicle C stopped traveling at time t22 after time t20.

(Fourth example)
The fourth example shown in FIG. 12 is an example in which the occupant protection device 11 can be activated while the vehicle speed condition and the deceleration period condition are satisfied. However, the relationship between the allowable deceleration period TDth and the allowable low speed period TLth is TDth <TLth as in the first example. The difference from the first example is that the speed threshold Vth is set lower than in the first example. Until time t13, the description is omitted because it is the same as the first example shown in FIG. 9 and the second example shown in FIG.

  Since the vehicle speed V (t) becomes equal to or less than the speed threshold Vth at time t30 after time t13, the deceleration period TD is counted starting from time t30 (step S42 in FIG. 7), and the low speed period TL is counted ( Step S52 in FIG.

  After time t30, the vehicle speed V (t) continues to decelerate, and at time t32, the deceleration period TD becomes equal to or greater than the allowable deceleration period TDth (step S43 in FIG. 7). According to the precondition of this example, the low speed period TL is within the low speed allowable period TLth. Since the deceleration period TD is equal to or longer than the allowable deceleration period TDth, the control unit 13 transmits the OFF control signal SD to the vehicle speed reflecting unit 15, and the vehicle speed reflecting unit 15 is in the non-conducting state of the switch unit Q by the OFF control signal SC. (Step S44 in FIG. 7). Therefore, until the time t32, the occupant protection device 11 is continuously activated, and the function of the entire occupant protection system 10 is stopped at the time t32. The vehicle C stopped traveling at time t31 before time t32.

(Fifth example)
The fifth example shown in FIG. 13 is an example in which the occupant protection device 11 can be activated while the vehicle speed condition and the low speed period condition are satisfied. The difference from the first example is that the supply voltage E1 becomes less than the voltage threshold Eth after the vehicle speed V (t) becomes equal to or less than the speed threshold Vth.

  While the vehicle C is traveling, the supply voltage E1 of the first power supply line L1 is a voltage Ea that exceeds the voltage threshold Eth until time t44. Similarly to the first example, the control unit 13 transmits the ON control signal SB to the activation unit 12, and the activation unit 12 sets the switch unit Q to the conductive state by the ON control signal SA (step S15 in FIG. 5). Since the voltage is lower than the voltage threshold Eth after time t44 (0 [V] in FIG. 13), the control unit 13 transmits the ON control signal SD to the vehicle speed reflecting unit 15, and the vehicle speed reflecting unit 15 is controlled to be ON. The switch portion Q is turned on by the signal SC (step S20 in FIG. 5). The switch unit Q remains conductive after time t44, and the power source unit 17 is supplied with power of the supply voltage E2 (voltage Eb in FIG. 13) from the battery BAT via the second power source line L2. Continue to be able to start.

  Until time t <b> 44, the control unit 13 can acquire the vehicle speed Vo from the external device 20 via the communication unit 14. After time t44, the current vehicle speed V is obtained using the vehicle speed Vo acquired in the predetermined period FT from time t41 to time t44 and recorded on the recording medium 13a and the acceleration a (t) acquired from the acceleration sensor 16. (t) is estimated (step S30 in FIG. 6). At time t43 prior to time t44, the vehicle speed V (t) becomes equal to or less than the speed threshold Vth. Therefore, the deceleration period TD is counted starting from time t44 (step S42 in FIG. 7), and the low speed period TL is counted. (Step S52 in FIG. 8).

  After time t44, the vehicle speed V (t) continues to be lower than the speed threshold Vth, and at time t45, the low speed period TL becomes equal to or higher than the low speed allowable period TLth (step S53 in FIG. 8). However, since the vehicle speed V (t) may increase between time t44 and time t45, the deceleration period TD is within the allowable deceleration period TDth. Since the low speed period TL is equal to or longer than the low speed allowable period TLth, the control unit 13 transmits the OFF control signal SD to the vehicle speed reflecting unit 15, and the vehicle speed reflecting unit 15 is in the non-conducting state of the switch unit Q by the OFF control signal SC. (Step S54 in FIG. 8). Therefore, until the time t45, the occupant protection device 11 is continuously activated, and the function of the entire occupant protection system 10 is stopped at the time t45. The vehicle C stopped traveling at time t46 after time t45.

  Although illustration is omitted, when the vehicle speed V (t) continues to decelerate as in the first example shown in FIG. 9, the deceleration period TD first becomes equal to or longer than the allowable deceleration period TDth (step S43 in FIG. 7). In this case, the control unit 13 transmits the OFF control signal SD to the vehicle speed reflection unit 15, and the vehicle speed reflection unit 15 sets the switch unit Q to the non-conduction state by the OFF control signal SC (step S44 in FIG. 7).

(Sixth example)
The sixth example shown in FIG. 14 is an example in which the ignition switch IGSW is turned on while the deceleration period condition is satisfied, and the occupant protection device 11 can be activated. As in the first example, the relationship between the allowable deceleration period TDth and the allowable low speed period TLth is TDth <TLth. Until time t14, the description is omitted because it is the same as the first example shown in FIG. 9 described above.

  After time t14, the vehicle speed V (t) continues to decelerate, and at time t51, the deceleration period TD becomes equal to or longer than the allowable deceleration period TDth (step S43 in FIG. 7). According to the precondition of this example, the low speed period TL is within the low speed allowable period TLth. However, at time t50 before time t51, the ignition switch IGSW is turned on, and the supply voltage E1 of the first power supply line L1 returns to the voltage Ea exceeding the voltage threshold Eth. Therefore, the ON control signal SB is transmitted to the activation unit 12, and the activation unit 12 sets the switch unit Q to the conductive state by the ON control signal SA (step S15 in FIG. 5). Although the vehicle C stops at time t52 after time t51, the occupant protection device 11 is continued to be activated regardless of whether or not the vehicle C is traveling.

[Other Embodiments]
Although the form for implementing this invention was demonstrated above, this invention is not limited to the said form at all. In other words, various forms can be implemented without departing from the scope of the present invention. For example, the following forms may be realized.

  In the above-described embodiment, the occupant protection system 10 is configured to include the activation unit 12 and the vehicle speed reflection unit 15 separately (see FIG. 2). Instead of this form, as shown in FIG. 15, it is good also as a structure provided with the switch control part 18 which integrated the starting part 12 and the vehicle speed reflection part 15. As shown in FIG. The switch control unit 18 has both the function of the activation unit 12 and the function of the vehicle speed reflection unit 15. Since there is only a difference between a separate configuration and an integrated configuration, the same operational effects as in the embodiment can be obtained.

  In the above-described embodiment, the battery BAT and the occupant protection system 10 are connected by one second power supply line L2 (see FIG. 2). Instead of this configuration, a redundant configuration in which the battery BAT and the occupant protection system 10 are connected by a plurality of second power supply lines L2. FIG. 16 shows second power supply lines L2a and L2b corresponding to the second power supply line L2. The second power supply line L2a and the second power supply line L2b are connected in parallel between the battery BAT and the occupant protection system 10. With the redundant configuration, even if one of the second power supply lines L2a and L2b is disconnected, power can be supplied by the other power supply line, and the occupant protection device 11 can be activated. . Further, by connecting in parallel, the combined resistance value between the battery BAT and the occupant protection system 10 can be reduced, and power loss due to the power line can be suppressed. Although not shown, a redundant configuration in which three or more second power supply lines L2 are connected in parallel may be employed. About the other, the effect similar to embodiment is obtained.

  In the embodiment described above, a transistor is used as the switch portion Q (see FIG. 2). Instead of this configuration, a relay may be used as the switch unit Q. The relay may be a magnetic type or a semiconductor type. Since power can be supplied from the battery BAT to the power supply unit 17, the same effects as those of the embodiment can be obtained.

  In the embodiment described above, a four-wheeled vehicle is applied as the vehicle C (see FIG. 1). Instead of this form, the vehicle C may be applied to a two-wheeled vehicle. That is, the present invention can be applied to a vehicle including the occupant protection device 11 regardless of the number of wheels or the power engine. Since only the type of the vehicle C is different, the same effect as the embodiment can be obtained.

  In the embodiment described above, positive logic is applied to ON / OFF of various signals (see FIGS. 9 to 14). Instead of this form, a configuration may be adopted in which negative logic is applied to ON / OFF of various signals. Since the assignment of logical values to physical values is only different, the same effect as the embodiment can be obtained.

DESCRIPTION OF SYMBOLS 10 Crew protection system 11 Crew protection device 12 Start part 13 Control part 15 Vehicle speed reflection part 16 Acceleration sensor 17 Power supply part BAT Battery C Vehicle L1 1st power supply line L2 2nd power supply line Q Switch part

Claims (7)

An occupant protection device (11) for protecting an occupant of the vehicle (C);
An acceleration sensor (16) for detecting the acceleration (a) of the vehicle;
A control unit (13) for controlling the operation of the occupant protection device based on the acceleration detected by the acceleration sensor;
A switch unit (Q) interposed between the battery (BAT) and the power source unit (17) and capable of switching between a conductive state and a non-conductive state;
In an occupant protection system (10) that converts electric power supplied from the battery via the switch unit and includes at least the occupant protection device, the acceleration sensor, and the power supply unit that outputs the control unit.
Depending on whether or not the supply voltage (E1) supplied from the battery to the first power supply line (L1) through the ignition switch (IGSW) is equal to or higher than the voltage threshold (Eth), the switch unit is turned on or off. An activation unit (12) for switching to one of the states;
A second power supply line (L2) for electrically connecting the battery and the power supply unit via the switch unit without passing through the ignition switch;
An occupant protection system comprising: a vehicle speed reflection unit (15) that switches the switch unit to either a conductive state or a non-conductive state based on a calculated value calculated using an acceleration detected by the acceleration sensor.   2. The occupant protection system according to claim 1, wherein the control unit performs control to switch the switch unit to a conductive state and continue as long as a predetermined condition is satisfied.   The occupant protection system according to claim 2, wherein the control unit includes a vehicle speed condition in which the speed (V) of the vehicle is larger than a speed threshold value (Vth) as the predetermined condition.   The occupant according to claim 2 or 3, wherein the control unit includes, as the predetermined condition, a speed non-acquisition condition in which the speed of the vehicle cannot be obtained from an external device (20) that is communicably connected. Protection system. The time when the supply voltage becomes less than the voltage threshold is set as a reference time (STD, t13, t44),
The control unit obtains the vehicle speed obtained in a predetermined period (FT) including the reference time and recorded on the recording medium (13a), and the acceleration detected by the acceleration sensor along with the passage from the reference time. The occupant protection system according to any one of claims 1 to 4, wherein the speed of the vehicle is estimated by performing a calculation according to (5). A period during which the vehicle speed continuously decreases is a deceleration period (TD),
The occupant protection system according to any one of claims 3 to 5, wherein the control unit includes a deceleration period condition in which the deceleration period is shorter than a deceleration allowable period (TDth) as the predetermined condition. A period during which the speed of the vehicle continues to be equal to or lower than the speed threshold is defined as a low speed period (TL),
The occupant protection system according to any one of claims 3 to 5, wherein the control unit includes, as the predetermined condition, a low speed period condition in which the low speed period is shorter than a low speed allowable period (TLth).

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