JPH01269641A - Trouble diagnosing and recording device for air bag device - Google Patents

Abstract

PURPOSE:To record the diagnosis data having high reliability by recording the trouble diagnosis data of an air bag device into an NVRAM (semiconductor nonvolatile memory) in multiple form and comparing said data in a processing part and detecting the trouble of a semiconductor nonvolatile memory (NVRAM) itself. CONSTITUTION:An air bag device 1 is constituted of a plurality of G sensors 1b1 and 1b2, squib 1c, and an electric power source 1a for feeding are ignition electric current of the squib 1c. If, in this case, the trouble of the air bag device 1 is detected by the detection part 2a of a processing part 2, said detection is judged by a microcomputer 2, and an alarm signal is outputted into an alarm device 3, and the trouble diagnosis data is written into an NVRAM 4. Further, when a detection part 2b detects the electric conduction of the squib 1c, the squib electric conduction data is written into the NVRAM 4 by the microcomputer 2c, and the writing-in of the data into the NVRAM 4 is prohibited.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is capable of detecting a failure of the semiconductor nonvolatile memory itself by multiplexing and comparing failure diagnosis data of an airbag device in a semiconductor nonvolatile memory. The present invention relates to a failure diagnosis recording device for a vehicle airbag device, which is capable of improving reliability.

[Conventional technology]

FIG. 6 is a block diagram showing a recording device of a conventional airbag device disclosed in, for example, Japanese Utility Model Application Publication No. 62-32926. 1), lc is a squib activated by the G sensor 1b, and the airbag device 1 is constituted by the G sensor 1a and the squib 1c.

Is 21 equipped with an airbag? Determination means for determining that the lfl is in an abnormal state; 3 an alarm for warning of the abnormal state in response to the determination by the determination means 21; 22, activation detection means for detecting activation of the squib IC; and 23, activation detection. This is a recording means for recording that the alarm has been issued in response to detection of activation of the means 22.

By the way, one of the issues that has been discussed in the past regarding airbag devices is the necessity of a method for investigating the cause when a non-operation such as non-deployment of an airbag occurs during a vehicle collision.

In the conventional example shown in FIG. 6, the presence or absence of a warning before the airbag device 1 is deployed or not deployed is recorded, and the purpose is to use this information to investigate the cause.

In FIG. 6, the determining means 21 constantly determines the failure of the airbag device 1 and issues an alarm to the alarm 3 when there is a failure, while the activation detecting means 22 detects the activation of the squib LC, that is, the ignition of current. At the same time, the presence or absence of the warning is recorded in the recording means 23.

[Problem to be solved by the invention]

Since the recording device of the conventional airbag device is configured as described above, there is no means or countermeasure for detecting a failure of the recording means 23 itself, and there is no confidence in the importance of the recording device of the airbag device as a recording device. There was a problem that gender was not guaranteed.

This invention was made in order to solve the above-mentioned problems, and it provides a failure diagnosis for an airbag device that can diagnose a failure of the recording device itself that records failure diagnosis data of the airbag device and notify the driver. The purpose is to obtain a recording device.

[Means to solve the problem]

A failure diagnosis recording device for an airbag device according to the present invention includes:
A processing unit that diagnoses multiple locations of the airbag device to determine failure and outputs diagnostic data; and a processing unit that multiplexes the diagnostic data output from the processing unit and stores the multiplexed storage contents in the processing unit. It is equipped with a semiconductor non-volatile memory (hereinafter referred to as NVRAM) for output.

[For production]

In this invention, the processing section diagnoses multiple locations of the airbag device, multiplexes the failure diagnosis data of the airbag device at multiple locations in the NVRAM, and stores the diagnostic data multiplexed in the NVRAM in the processing section. NVRAM in comparison
Detects a bit failure.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings. 1st
The figure is a block diagram showing the overall configuration. In the figure, Ibl and Ib2 are G sensors, lc is a squib, and 1a
is a power source that can flow enough current to ignite the squib 1c.

1 is these power supply 1a, G sensor lbl, 1b2
.

This is an airbag system consisting of a squib LC.

2a is a failure detection unit that detects a failure of the airbag device 1;
2b is a squib energization detection unit that detects that ignition current has flowed to the squib 1c; 2c is a microcomputer (hereinafter abbreviated as microcomputer) that receives and processes the outputs of the failure detection unit 2a and the squib energization detection unit 2b; Failure detection section 2a
, a squib energization detection section 2b, and a microcomputer 2c.

3 is an alarm device controlled by the microcomputer 2c, and 4 is an NVRAM to which data is written and read from the microcomputer 2c.

Next, the operation will be explained. If the microcomputer 2c constantly checks the output of the failure detection section 2a and determines that there is a failure, it issues an alarm to the alarm device 3 and writes failure diagnosis data to the NVRAM 4 at the same time.

Further, when the squib energization detection section 2b detects ignition current energization, the microcomputer 2c writes the squib energization data to the NVRAM4, and then prohibits writing to the NVRAM4.

By doing so, the squib energization, that is, the state of the airbag device before the vehicle collision is recorded regardless of whether the airbag is deployed or not.

Next, a method of writing to the NVRAM 4 will be specifically explained. FIG. 2 is a conceptual diagram showing the exchange of data between the microcomputer 2c and the NVRAM 4. For example, 5 is an 8-bit microcomputer memory whose flags ■ to ■ correspond to the presence or absence of various failures in the airbag device l, and 6 is a block A. ,B,C
A part of NVRAM consisting of two parts, 6a, 6b,
6c is a part of the NVRAM 6 in which the contents of the microcomputer memory 5 are written into blocks A, B, and C.

Writing to and reading from the NVRAM 6 in FIG. 2 will be explained with reference to flowcharts in FIGS. 3 to 5. Figure 3 shows the write subroutine, where the main arguments are write data and block type.First, in step S1, A, B, C
Branches depending on which block to write to, and goes to step 8.
In steps 2 to s4, assign o1 for block A, 1 for block B, and 2 for block C to the rotation bit number R in steps 2 to s4.In step S5, the write data is rotated to the right by R bits.In step S6, the write data is rotated to the right by R bits. Performs a write operation WRITE to.

Figure 4 shows the read subroutine, where the input argument is the block type, the output argument is the read data, and step Sl
Steps 1 to S14 are similar to step 5t-34 in FIG. 3, in which a read operation READ is performed in step 315, and the read data is rotated to the left by R bits in step 316.

By doing this, the NVRAM 6 in FIG.
In this case, the data in blocks B and C are obtained by rotating the data in block A to the right by 1 bit and 2 bits, respectively.

There are two ways to detect failures in NVRAM, as shown in Figure 5 (al), when one piece of data is written in step 317, that data is immediately read out in step 318, and compared with the written data in step S19. ,
A method for detecting a failure by setting an error flag in step S20, and a method for detecting a failure by setting an error flag in step S20, and
, C, and compare these data with each other in step S22. If they do not match, the process proceeds to step S23.
There is a method of detecting a failure by setting an error flag.

As described above, according to this embodiment, when writing diagnostic data to NVRAM, the NVRAM is
Even if a RAM failure is detected and there has been no writing to NVRAM for a long time, use the method shown in Figure 5 to update NVRAM.
can detect failures.

Additionally, semiconductor memories are generally configured in a matrix with bit lines and word lines, as shown in Figure 2 (
By configuring the recorded data of the NVRAM, the bit line is rotated and the focus is shifted for each block, and the word line is written with the same data in three blocks. This has the effect of being able to detect failures in both the bit line and word line of the NVRAM.

Furthermore, the above method has the advantage that bit errors in memory can be detected in a simple manner without providing special bits such as parity bits.

Furthermore, when an NVRAM failure is detected as described above,
In FIG. 1, the microcomputer 2C can notify the driver of an abnormality in the failure diagnosis recording device by issuing an alarm to the alarm device 3.

On the other hand, even if a failure occurs in the NVRAM 4, if the same data is recorded in several places as described above, there is an effect that the failure diagnosis state can be estimated by taking a majority vote.

In the above embodiment, the same data was recorded in three blocks of the NVRAM in a modified form, but there is no problem even if the number of blocks is larger than this, and the effect of majority voting becomes greater.

Furthermore, in the method of rotating data by 2 bits as described above as a data transformation method, the same effect as described above can be obtained even if the number of rotated bits is changed appropriately.

Furthermore, in the above embodiment, an 8-bit flag was used as an example of the diagnostic data recorded in the NVRAM, but the number of bits of data may be other than 8 bits, and numerical data other than flags may also be used as failure diagnosis record data. obtain.

〔Effect of the invention〕

As described above, according to the present invention, the failure diagnosis data of the airbag device is multiple recorded in the NVRAM and compared in the processing section to detect a failure of the NVRAM itself. When an NVRAM is used as a recording device, the NVRAM itself can be constantly monitored for failures, and highly reliable diagnostic data can be recorded.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of a failure diagnosis recording device for an airbag device according to an embodiment of the present invention, Fig. 2 is a conceptual diagram showing data exchange between a microcomputer and NVRAM in the embodiment of the above, and Fig. 3 is an implementation of the same. FIG. 4 is a flowchart of the NVRAM 4 read subroutine in the above embodiment, and FIGS. 5(a) and 5(1)) respectively show the NVRAM failure detection method in the above embodiment. The flowchart shown in FIG. 6 is an overall configuration diagram showing a conventional recording device for an airbag device. 1...Airbag device, 2...Processing unit, 3...Alarm device, 4...Semiconductor nonvolatile memory. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa Figure 2 VRAM Figure 5 (0) (b) Figure 6!

Claims (1)

[Claims] A processing unit that diagnoses multiple locations of the airbag device to determine failure, multiple recording of diagnostic data output from this processing unit, and comparing the multiple recorded diagnostic data in the processing unit to detect a bit error failure. A failure diagnosis recording device for an airbag device, comprising: a semiconductor nonvolatile memory; and an alarm that is controlled by the processing section and issues an alarm when the airbag device and the semiconductor nonvolatile memory fail.