JPH1169663A - Driver of occupant protector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To start a starter to which a power is supplied later securely when powers are supplied to a plurality of starters whose optimum start timings are different by a common auxiliary battery. SOLUTION: A driver supplies starting powers to a plurality of starters 20 and 30 whose optimum start timings are different to start a crew protector. For that purpose, an auxiliary battery 51 which is connected in parallel to a main battery 11 and supplies starting powers in common to a plurality of the starters when the power supply from the main battery is disabled, a voltage detector 60 which detects the voltage of the auxiliary battery 51 and a current application controller 70 which, after the starting powers are supplied to the respective starters with their optimum timings when a vehicle collision is detected, if the voltage detected by the voltage detector 60 is lowered to a predetermined voltage set in a voltage region which permits the secure operations of the other starters, discontinues the supply of the starting power to the starter under current application are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving device for a vehicle occupant protection device such as an airbag and a seatbelt pretensioner which are driven at the time of a vehicle collision. In particular, the present invention relates to a device improved so as to reliably start a plurality of activation devices when a plurality of activation devices having different optimum activation timings are activated by a common auxiliary battery.

[0002]

2. Description of the Related Art In addition to a structure in which starting power is supplied from a main battery at the time of starting, an occupant protection device for a vehicle reliably protects even when a power supply line from the main battery is disconnected due to an impact at the time of a collision. Is configured to be able to be supplied with power from an auxiliary battery so as to be activated (Japanese Patent Laid-Open No. 6-1071).
No. 19). In order to save power stored in the auxiliary battery and supply power to the computer even after the occupant protection device has been activated and save various data in the event of a collision, the current must be supplied after a certain period of power-on. It is shut off. However, when the current is interrupted for a certain period of time, if a mechanical safing sensor is used, there is a problem that the current actually flowing due to chatter is not sufficient and the occupant protection device cannot be started. Therefore, in the above publication, the time during which the transistor for controlling the energization timing of the start-up circuit is on and the mechanical safing sensor is actually on is cumulatively added, and the cumulative addition time exceeds a predetermined value. When the occupant protection device was securely activated when
The energization after that is stopped.

On the other hand, when a plurality of occupant protection devices are connected in parallel to the main battery, if one starting circuit is short-circuited, current concentrates on that circuit, and sufficient current does not flow through the other starting circuits. In order to solve this problem, a device has been known in which an auxiliary battery is provided for each occupant protection device so that a short-circuit failure of one starting circuit does not affect another starting circuit (Japanese Patent Application Laid-Open No. Hei 8-8). 133004).

[0004] Further, each occupant protection device has a different optimum starting time with respect to the collision time. For example, there is a time difference between the start timing of the seat belt pretensioner and the airbag,
2. Description of the Related Art A passenger seat airbag that can be activated in multiple stages is activated in multiple stages with a time difference.

[0005]

Problems to be Solved by the Invention
The method described in Japanese Patent Publication No. 9 is for driving one occupant protection device. However, since the actual ON time of the mechanical safing sensor is cumulatively added, the method is simpler than when setting the time simply. Thus, the current conduction time becomes accurate. However, the energization time is not always accurate for the following reasons.
The ON timing of the safing sensor is discretely monitored by sampling of the CPU by a timer interrupt.
Therefore, during the execution cycle due to the timer interrupt, since the energization time is not actually monitored, an accurate energization time cannot be obtained. In addition, this publication does not disclose an application to a device having a time difference in startup timing. Even if it is applied, if the energization time in a plurality of occupant protection devices overlaps, it is difficult to accurately predict the remaining power of the auxiliary battery based on the energization time, so the energization is individually turned off. Time is not available. Furthermore, since the current value and the voltage value are not measured, the remaining power of the auxiliary battery cannot always be accurately grasped only by the energization time. Therefore, the energization time is not enough to determine whether or not enough electric power remains to operate another occupant protection device that requires large electric power later. Further, if an auxiliary battery is provided for each occupant protection device as disclosed in JP-A-8-133004, resistance,
There is a problem that the number of components such as diodes and capacitors increases, and the device configuration becomes complicated.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to supply power to a plurality of starting devices having different optimum starting timings by using a common auxiliary battery so that a starting device to be supplied later can be started reliably. That is, the power supply to the activated starting device is cut off at an appropriate time.

[0007]

According to the first aspect of the present invention, each of the starting devices is cut off when the detected auxiliary battery voltage drops to a predetermined voltage after the starting power is supplied. You. This predetermined voltage is set in a voltage range in which other starting devices can be reliably operated. Also, unlike the energization time, the voltage of the auxiliary battery accurately reflects the remaining power. In this way, by stopping the energization in accordance with the actual voltage of the auxiliary battery, it is possible to reliably start the remaining starting devices.

According to the second aspect of the present invention, the predetermined voltage is set for each operating starter. For this reason, even when the energization periods partially overlap due to the relationship of the optimal start timing, it is possible to accurately determine the time to cut off the energization for each activation device,
The activated occupant protection device can be reliably operated and the remaining unactivated occupant protection devices can be reliably operated.

According to the third aspect of the present invention, the predetermined voltage is set to a value which the voltage of the auxiliary battery takes after a lapse of time during which sufficient power is supplied to completely activate each energized starting circuit. Have been. For this reason, each energizing starting circuit can be reliably started, and the occupant protection device can be reliably operated.

According to the present invention, the supply of the starting power to the energized starting device is stopped at least after a lapse of a predetermined time during which the starting device can be completely started. Is prevented from being stopped when the start-up is incomplete.

[0011] According to the invention of claim 5, the plurality of starting devices are a first starting device having an optimum starting time earlier than a vehicle collision detecting time and a second starting device having an optimum starting time later than the first starting device. Since the starting device is included, at least two starting devices can be reliably operated.

According to the sixth aspect of the present invention, the predetermined voltage is set in a voltage range in which the voltage of the auxiliary battery reaches after a lapse of time during which sufficient power is supplied to completely activate the first activation device. In addition, the value is set to a voltage range in which the second starting device can be started. Therefore, after the first activation device is reliably activated, the activation of the second activation device having a late optimal activation time can be reliably completed.

According to the seventh aspect of the present invention, the first starting device is a starting device for operating the seat belt pretensioner, and the second starting device is a starting device for operating the airbag. The seatbelt pretensioner and the airbag activated later can be reliably operated.

According to the present invention, the first activation device is an activation device for activating the airbag for the driver's seat, and the second activation device is an activation device for activating the airbag for the passenger's seat. Therefore, the driver-side airbag and the passenger-side airbag activated later than the driver-side airbag can be reliably operated.

According to the ninth aspect of the present invention, since the plurality of starting devices are used as the starting devices for operating the occupant protection device in multiple stages, the occupant protection device that is started in multiple stages is provided by the auxiliary battery. The operation can be surely completed to the end.

According to the tenth aspect of the present invention, one of the switches for turning on at the time of a vehicle collision and supplying power to the occupant protection device is a sensor having a mechanical contact. Even if the sensor chatters and the energizing current is interrupted, the voltage of the auxiliary battery decreases in accordance with the consumed power. Therefore,
Even if the power supply is intermittent, the remaining power of the auxiliary battery can be more accurately predicted, unlike the case of controlling by the macro power supply time. The operation can be completed.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to embodiments. FIG. 1 shows a configuration of a driving device of an occupant protection device according to a specific embodiment of the present invention. The first ignition circuit (first starting device) 20 includes a first squib 22
And a first ignition switch 21 composed of a transistor, and a first constant current circuit 24 composed of a transistor circuit for making the flowing current constant. The second ignition circuit (second starting device) 30 includes a second squib 32, a second ignition switch 31 composed of a transistor, and a second constant current circuit 34 composed of a transistor circuit that keeps a constant current flowing. Have been. The first ignition circuit 20 and the second ignition circuit 30 are connected in parallel, and the parallel connection circuit is connected in series to the third ignition switch 16 constituted by a mechanical safing sensor. The first ignition circuit 20 and the second
The ignition circuit 30 includes a main battery 11 composed of a vehicle-mounted battery, a key switch 12 of the vehicle, a backflow prevention diode 13,
The power is supplied via the booster circuit 15 and the third ignition switch 16. The backup circuit 50 is connected to the main battery 11.
Are charged through the booster circuit 15 from the first and second
The ignition circuits 20 and 30 are connected so as to be able to supply power. The backup circuit 50 includes an auxiliary battery 51 composed of a backup capacitor charged from the main battery 11 and a charging resistor 52 and a discharge diode 53 connected in series with each other and connected in parallel with each other.

The first ignition switch 21 and the second ignition switch 31 are turned on by a start signal from the power supply control device 70. The energization control device 70 determines the optimal start time and the ignition switch energization cutoff time by determining a collision by performing an integration operation or the like on the detected acceleration and a G sensor 71 for detecting acceleration acting upon a vehicle collision. And a microcomputer 72 to be used. Voltage detector 6
0 is the proportional voltage of the terminal voltage V of the auxiliary battery 51 (hereinafter, referred to as
(Referred to simply as terminal voltage) by resistance division. The detected terminal voltage V is read by the microcomputer 72.

When a vehicle collides, the occupant protection device is driven by such a device.
When the main battery 11 is unable to supply power to the first and second ignition circuits 20 and 30, the auxiliary battery 51 supplies power to those circuits.
Also, the optimal start timing of the first ignition circuit 20 is determined by the second ignition circuit 3
0 is earlier than the optimal start time.

Next, the operation of the present apparatus will be described with reference to the flowchart of FIG. The processing procedure shown in FIG. 2 is started by a timer interrupt every predetermined time. Steps 101 to 106 are processing steps involved in the collision determination. In step 101, it is determined whether or not the flag 1 is set. The set state of the flag 1 means a state determined to be a collision, and the reset state means a state not determined to be a collision. In step 102, the G sensor 71
Is input. In step 103, when the acceleration exceeds the first level, a subsequent integral calculation of the acceleration is started, and when the acceleration falls below the first level, the integral value is reset to zero. Then, in step 104, it is determined whether or not a collision has occurred based on whether or not the acceleration integrated value calculated in this manner is greater than a predetermined second level. If it is determined that there is no collision, the execution of this cycle is completed, and the processing is restarted from step 101 in synchronization with the next timer interrupt.

On the other hand, if it is determined in step 104 that a collision has occurred, flag 1 is set in step 105, and a timer is reset in step 106 for time measurement. Steps 114 to 116 are processing steps for turning on the first ignition switch 21. In step 114, the first ignition switch 21 is turned on at the optimal start timing, and in step 115, the flag 2 is set. The set state of the flag 2 means the ON state of the first ignition switch 21, and the reset state means the OFF state. next,
In step 116, it is determined whether or not it is time to turn on the second ignition switch 31 (optimal start time). If it is not the start time, the processing of this cycle is finished, and the processing is restarted from step 101 at the time of the next timer interruption.

In step 101 after the collision is determined, the flag 1 is determined to be in the set state, and in step 110, the timer is started. Step 111
Steps -113 are steps for determining whether it is time to turn off the first ignition switch 21. When it is determined in step 111 that the flag 2 is in the set state, the first ignition switch 21 is in the on state, and in step 112, it is determined whether the minimum on-time T4 has elapsed.
The minimum on-time T4 is a predetermined time necessary for sufficiently operating the first squib 22. At least as long as the minimum on-time T4 does not elapse, the first ignition switch 21 is not turned off. Thereby, the first ignition circuit 20 is reliably started.

Next, if it is determined that the first ignition switch 21 has passed the minimum on-time T4, the routine proceeds to step 1
At 13, it is determined whether the terminal voltage V of the auxiliary battery 51 is equal to or lower than a predetermined voltage V1. The terminal voltage V is a predetermined voltage V
If it is higher than 1, the processing of steps 114 to 116 is executed. Note that the process of turning on the first ignition switch 21 is performed in steps 114 and 115,
When the first ignition switch 21 is turned on, the activation signal output from the microcomputer 72 to the first ignition switch 21 is held, so that there is no change in the activation signal. Further, in step 116, it is determined whether or not the second ignition switch 31 is on (optimal start-up time).
The following control for turning on the second ignition switch 31 is performed. Therefore, depending on the relationship of the optimal start timing, the second ignition switch 31 may be turned off even before the first ignition switch 21 is turned off.
May be set to be turned on.

In step 113, the auxiliary battery 51
Is lower than the predetermined voltage V1, the first ignition switch 21 is turned off in step 120, and the flag 2 indicating this is reset in step 121.

Steps 122 to 123 are processing steps for turning on the second ignition switch 31, and step 124
To 126 are the first ignition switch 21 and the second ignition switch 3
This is a processing step for turning 1 off. In step 122, it is determined whether or not the second ignition switch 31 has been turned on (optimum start-up time). If not, the execution cycle ends. If it is the ON time, in step 123, the second ignition switch 31 is turned on. In step 124, it is determined whether or not the maximum on-time sufficiently longer than the minimum on-time T4 has elapsed. If it has elapsed, in step 125, the first and second ignition switches 21, 31 are turned off. A signal is output. However, the first
If the condition of step 113 is satisfied, the ignition switch 21 is already off at this time. In this way, all the occupant protection devices to be driven in the event of a collision are completely activated, and in step 126, the flag 1 is reset, and the processing in the event of a collision ends. When power is supplied from the main battery 11, the terminal voltage V of the auxiliary battery 51 does not decrease, and the condition of step 113 (V ≦ V1) is not satisfied. Therefore, the determination of the lapse of the maximum on-time in step 124 is used to determine the timing for turning off the first and second ignition switches 21 and 31 when the power is supplied from the main battery 11.

Next, a typical operation of the present apparatus will be described with reference to the timing chart of FIG. Time t1 is the vehicle collision time. The time from t1 to t2 is the time required until the collision condition is satisfied (the time until the flag 1 is set). The auxiliary battery 51 is discharged to supply power to the power supply control device 70, and the terminal voltage V gradually decreases in the period T0.

Time t2 is the optimal start timing of the first ignition circuit 20, and when time t2 is reached, the first ignition switch 21
Is turned on (steps 105, 106, and 114), a large current flows, and the terminal voltage V of the auxiliary battery 51 drops significantly in the period T1 (repeated period of steps 110 to 116). Next, when the terminal voltage V becomes equal to or lower than the predetermined voltage V1 at time t3 (step 113),
The first ignition switch 21 is turned off. At this time t3, the occupant protection device activated by the first squib 22 is completely operated.

Next, a period T from the time t3 to the time t4.
In step 2 (repetition of steps 111, 120, 121, 122), the terminal voltage V of the auxiliary battery 51 gradually decreases due to power supply to the power supply control device 70 as in the period T0. Then, at time t4, the second ignition switch 31 comes to the optimal start timing, so the second ignition switch 31
Is turned on (step 123). And then
Until time t5 (step 124) at which it is determined that the maximum on time has elapsed, the second ignition switch 31 continues to be in the on state, and is turned off at that time t5 (step 125).

The predetermined voltage V1 is set as follows. After the first ignition switch 21 is turned on at time t2,
When the minimum on-time T4 required for completely starting the first squib 22 has elapsed, the terminal voltage V
Is set to a voltage range A which is lower than the voltage V0 and which is equal to or higher than the minimum voltage V2 at which sufficient power is supplied to the second squib 32 and sufficient power is supplied to fully operate the occupant protection device. Have been. Thereby, the first squib 22
And the second squib 32 can be completely activated.

It is also possible to operate as shown in FIG. Time t12 is the time when the first ignition switch 21 is turned on, and the second ignition switch 31 is turned on at time t13 before it is turned off. When the terminal voltage V of the auxiliary battery 51 reaches the predetermined voltage V1, the first
The ignition switch 21 is turned off. As a result, the second squib 32 is sufficiently supplied with power during a period after the time t14, so that a reliable start is achieved. Also in this case, the predetermined voltage V1 is set in the voltage region A described above.

In the above embodiment, the number of squibs is two, but it can be three or more. Also in this case, when the energization of the energized squib is turned off, the predetermined voltage may be set in a voltage region in which power can be sufficiently supplied to the squib whose energization is completed after the off time.
For example, when the number of squibs is three, it is assumed that the optimal start time is earlier in the order of the first squib, the second squib, and the third squib. As shown in FIG. 5, the terminal voltage V of the auxiliary battery is a first predetermined voltage at which the terminal voltage V of the auxiliary battery is a voltage sufficient to completely start the other second squib and the third squib at the time t23 when the energization of the first squib is cut off. V11. or,
The time t24 at which the energization of the second squib is cut off is determined by the terminal voltage V
Becomes a second predetermined voltage V12 which is a voltage sufficient to completely start up the other third squib. With this setting, the three squibs can be completely started. Incidentally, also in the case of FIG. 5,
The squib energization periods may overlap.

In the above embodiment, the occupant protection device activated by the first squib 22 is a driver airbag and the occupant protection device activated by the second squib 32 is a passenger airbag. Can be reliably operated with a common auxiliary battery. Further, the occupant protection device activated by the first squib 22 is a seat belt pretensioner, and the occupant protection device activated by the second squib 32 is an airbag. Can be activated.

The first squib 22 and the second squib 32
The occupant protection device activated in the above may be an airbag that is deployed in two stages. The first squib 22 is actuated first to perform the first deployment of the airbag, and then to the second
The squib 32 is activated to perform the second deployment of the airbag.
With this device, the multistage deployment of the airbag can be reliably performed even with the auxiliary battery.

In the above embodiment, a mechanical safing sensor is used for the third ignition switch 16. With this sensor, chattering occurs at the time of collision, but the auxiliary battery 51
Terminal voltage V accurately reflects the actually consumed power regardless of chattering. Therefore, by comparing the terminal voltage V of the auxiliary battery 51 with the predetermined voltage, the activation of another ignition circuit can be ensured.

In place of the third ignition switch 16, an electric third ignition switch 204 shown in FIGS. 6 and 7 may be used. The circuit shown in FIG. 6 is provided with an on-hold circuit 203 for holding the contact state of the mechanical switch 201 to prevent chattering. In the circuit of FIG. 7, the microcomputer 206 controls the ON timing, and the third ignition switch 204 does not chatter. As described above, even if the third ignition switch does not cause chattering, the use of the present apparatus can ensure the start-up. When monitoring the ON state of the switch, only the ON state of the third ignition switch is monitored, and the actual ON state of the first ignition switch is not detected. That is, the ON timing of the first ignition switch is determined by the command timing by the microcomputer. Therefore, if the first ignition switch has a response delay, the actual energization time becomes shorter than the measured value. In this case, the first squib may not be completely started. However, the present device detects the actual voltage of the auxiliary battery and determines the timing of stopping the first squib, so that the start is insufficient. Will not be.

Although it is conceivable to actually detect the ON state of the first ignition switch, there is a problem that the detection circuit becomes complicated as the number of squibs increases. However, in this apparatus, only the terminal voltage of the common auxiliary battery is detected, so that such a problem does not occur even if the number of squibs increases. Further, when power is supplied from the main battery, the power supply capacity is sufficient, so that the above-described processing does not need to be performed. In that case, in the device of the present invention, a decrease in the terminal voltage of the auxiliary battery does not occur. Therefore, since the terminal voltage does not drop to the predetermined voltage, the specific processing when the power is supplied by the auxiliary battery is not executed. As described above, the present apparatus does not need to detect that power is not being supplied from the main battery in order to perform the above-described specific processing, and automatically performs the specific processing when power is being supplied from the auxiliary battery. Be executed.

In the above embodiment, the microcomputer 72 is used as the power supply control device for interrupting the supply of power to the previously ignited squib. However, as shown in FIG. May be used. That is, the cutoff time of the current of the power supply control device 70 may be determined by the comparator 63 and the reference battery 64 that supplies the predetermined voltage V1. The determination in step 113 of FIG.
The control for turning off the first ignition switch 21 by 20 is executed by the comparator 63. At this time, the microcomputer 72 controls only the ON timing of the first ignition switch 21 and the second ignition switch 31. Due to the resistance 73 connected to the output terminal of the microcomputer 72, the low level output from the comparator 63 takes precedence over the high level output from the microcomputer 72, so that the terminal voltage V of the auxiliary battery 51 has reached the predetermined voltage V1. Sometimes, the first ignition switch 21 can be turned off.

In the above embodiment, the voltage detecting device 60 detects the terminal voltage of the auxiliary battery 51. However, the voltage detecting device 60 may detect the cathode voltage of the discharge diode 53.
Further, in the above embodiment, the collision determination is commonly performed for a plurality of occupant protection devices. However, the collision determination may be performed individually for each occupant protection device. Also in this case, the above-described control method can be used to supply power from the common auxiliary battery and determine the timing of turning off the current to the energizing starter.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a configuration of a driving device according to a specific embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure of a CPU of the driving device.

FIG. 3 is a timing chart showing an operation state of the apparatus.

FIG. 4 is a timing chart showing an operation state of another device.

FIG. 5 is a timing chart showing an operation state of another device.

FIG. 6 is a circuit diagram showing another configuration of the third ignition switch.

FIG. 7 is a circuit diagram showing another configuration of the third ignition switch.

FIG. 8 is a circuit diagram showing a configuration of a driving device according to another embodiment.

[Explanation of symbols]

 11: Main battery 16: Third ignition switch 20: First ignition circuit (first starting device) 21: First ignition switch 22: First squib 30: Second ignition circuit (second starting device) 31: Second ignition Switch 32 second squib 50 backup circuit 51 auxiliary battery 60 voltage detection device 70 conduction control device

Claims (10)

[Claims] A drive device for supplying start-up power to a plurality of start-up devices having different optimum start-up times with respect to a vehicle collision detection time to start an occupant protection device, wherein the drive device is connected in parallel to a main battery. An auxiliary battery that supplies the start-up power to the plurality of start-up devices in common when the supply of power from the power supply is impossible, a voltage detection device that detects a voltage of the auxiliary battery, and when the vehicle collision is detected, After supplying the starting power to each starting device at their optimal starting time,
When the voltage detected by the voltage detection device is reduced to a predetermined voltage set in a voltage region in which another activation device can be reliably operated, energization for stopping supply of the activation power to the energization activation device. A driving device for an occupant protection device, comprising: a control device. 2. The drive device for an occupant protection device according to claim 1, wherein the predetermined voltage is set for each activation device that is energized. 3. The predetermined voltage is set to a value at which the voltage detected by the voltage detection device reaches after a lapse of time during which sufficient power is supplied to completely activate each energized starting device. The driving device for an occupant protection device according to claim 1 or 2, wherein the driving device is provided. 4. The power supply apparatus according to claim 1, wherein the supply of the start-up power to the energized start-up device is stopped at least after a lapse of a predetermined time during which the start-up device can be completely started. The driving device for an occupant protection device according to claim 1. 5. The plurality of starting devices include a first starting device having an optimum starting time earlier than a vehicle collision detecting time, and a second starting device having an optimum starting time later than the first starting device. The driving device for an occupant protection device according to any one of claims 1 to 4, wherein: 6. The voltage range in which the voltage detected by the voltage detection device reaches after a lapse of time during which power sufficient to completely start the first activation device is reached, And a value set in a voltage range in which the second activation device can be activated.
The driving device for an occupant protection device according to claim 1. 7. The starting device according to claim 1, wherein the first starting device is a starting device for operating a seat belt pretensioner.
The driving device for an occupant protection device according to claim 5, wherein the activation device is an activation device for activating an airbag. 8. The system according to claim 1, wherein the first activation device is an activation device for activating an airbag for a driver seat, and the second activation device is an activation device for activating an airbag for a passenger seat. The driving device for an occupant protection device according to claim 5 or 6, wherein 9. The occupant protection according to claim 1, wherein the plurality of activation devices are activation devices for operating the occupant protection device in multiple stages. The drive of the device. 10. A sensor according to claim 1, wherein a switch having a mechanical contact is used as one of switches for turning on at the time of a vehicle collision and supplying power to the occupant protection device. The driving device for an occupant protection device according to claim 1.