JPS6332318A - Vehicle data gathering device - Google Patents

Abstract

PURPOSE:To prevent gathered data from being misstored owing to radio wave disturbance and to improve the reliability of the data by providing an external noise extracting means and predicting the misstorage of the gathered data due to an external noise by a misstorage predicting means by monitoring the level of an extracted noise. CONSTITUTION:Detection signals supplied from sensors 10-1, 10-2...10-N to an interface 14 are waveform-shaped and amplified, A/D converted, and then processed by a CPU16 according to a program to obtain gathered data. Those data are written in the RAM of a storage device 20 to obtain a reset signal 100 when the output voltage of a voltage regulator 26 drops abnormally, and the CPU16 stops the generation of gathered data to inhibit data from being written in the RAM. Consequently, if the external noise of a level signal 106 exceeding a set level is superposed upon a detection signal 102, the CPU16 generates no gathered data, so no wrong gathered data is stored in the RAM of the device 20 and writing operation is inhibited. Therefore, the gathered data which are written so far are not destroyed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle data recording device that records data indicating the state quantity of a predetermined portion of a traveling vehicle.

(Prior art and its problems) Regarding this type of device, Japanese Patent Laid-Open No. 56-63972 is known, and an example thereof is shown in FIG.

Sensors 10-1, 10-2...10-N in the same figure are attached to each part of the vehicle, and these sensors 10-1, 10-2...10-N are
-1. Temperature by 10-2...10-N.

Various state quantities such as humidity and stress are detected.

Then, those detection signals (state quantity detection signals) are sent to the processing circuit 12 via the input interface 14 to CPtJ.
16, and the CPU 16 generates recorded data from these detection signals according to the contents of the ROM 18.

Roughly recorded data is stored in the storage device 20, and the storage is continued over the vehicle driving test period.

Thereafter, when the vehicle running test is completed, the recorded data is read from the storage device 20, statistical processing is performed using the read data, and the results are displayed in graphs, tables, etc.

(Problems to be Solved by the Invention) Here, when the vehicle travels during the test in a location where radio waves from an in-vehicle radio, television, radio, etc. are strong, the sensor 10-1.
10-2. . . . External noise caused by these radio waves enters into the detection signal of 10-N.

For this reason, in the past, there has been a problem that recorded data with incorrect contents are recorded, or an erroneous storage operation is performed that destroys all recorded data.

The present invention has been made in view of the above-mentioned conventional problems,
The purpose is to provide a vehicle data recording device that can prevent the above-mentioned erroneous storage due to radio wave interference and improve the reliability of recorded data.

(Means for Solving the Problems) In order to achieve the above object, the present invention extracts the external noise mixed into the state quantity detection signal of a predetermined part of the vehicle by an external noise extraction means, and extracts the recorded data due to the external noise. The present invention is characterized in that an erroneous memory of the recorded data is predicted by the erroneous memory prediction means by monitoring the level of extracted noise, and when an erroneous memory of the recorded data is predicted, consideration of the recorded data is prohibited by the data recording prohibition means.

(Description of Embodiments) Hereinafter, preferred embodiments of the apparatus according to the present invention will be described based on the drawings.

In FIG. 1, sensor 10-1. 'to-2...10
The detection signal applied from -N to the input interface 14 is waveform-shaped by a waveform shaping circuit within the input interface 14 and amplified by a differential amplifier.

Then, within the input interface 14, these amplified signals are given to a multiplexer and converted into a serial digital signal by an A/D converter.

They are processed by the CPU 16 according to the program in the ROM 18, thereby obtaining recorded data.

Roughly, the recorded data is given to the storage device 20 and written to the RAM provided in this storage device 20.

Further, an on-vehicle battery 22 is used as a power source for this embodiment, and its output voltage is supplied to various parts via a switch 241 and a three-terminal voltage regulator 26.

The output voltage of the voltage regulator 26 is monitored by a power supply voltage monitoring circuit 28, and the power supply voltage monitoring circuit 28 detects when the power is turned on by turning on the switch 24, and when the output voltage of the voltage regulator 26 drops abnormally. At this time, the reset signal 100 is obtained.

The reset signal 100 is supplied to the CPU 16 of the processing circuit 12 and the gate circuit provided in the storage circuit 20 via the OR circuit 30, and the reset signal 100 controls the CPU 16 to stop the generation of recorded data and stores the data. In the device 20, writing of recorded data to the RAM is prohibited by the gate circuit.

Here, when the vehicle passes through a location where strong radio waves exist, a high frequency component 104 due to the radio waves is mixed into the detection signal 102 of the sensor 10-N as external noise as shown in FIG. 3(A).

The detection signal 102 is supplied to the high frequency detection circuit 34 of the external noise monitoring circuit 32, and in the high frequency detection circuit 34, the high frequency component 104 of FIG. 3(B) is extracted from the detection signal @102 by the bypass filter 36. .

Next, when the level signal 106 shown in FIG. 3(C) is obtained by the envelope detection circuit 38, the level signal 10
6 is given from the high frequency detection circuit 34 to the level comparator 40, and the level comparator 40 receives the level signal 10.
6 and the setting level 0 are compared.

This set level Vo is set to a value at which the above-mentioned radio wave interference occurs, and the value has been determined through experiments.

FIGS. 3(C) and (D> explain the comparison action of the level comparator 40, in which the level comparator 40 obtains a comparison signal 108 that becomes L level when the level signal 106 exceeds the set level Vo. ing.

The comparison signal 108 is applied to the signal delay circuit 42, and the signal delay circuit 42 obtains the reset signal 110 shown in FIG. 3(E).

This reset signal 110 is applied to the OR circuit 30 together with the reset signal 100 of the power supply voltage monitoring circuit 28.

Therefore, for example, as shown in FIG. 3(F), the time t.

When the power is turned on, the CPU 16 performs the recorded data generation process (or all In addition, in the storage device 20, writing of recorded data to the RAM is prohibited by its gate circuit.

Therefore, according to this embodiment, when the external noise (high frequency component 104) of the level signal (106) exceeding the set level Vo is mixed into the detection signal 102, the CPU 16 does not generate recorded data, so the storage device 20 Wrong recorded data will not be stored in RAM, and the RAM
Since writing to M is prohibited, recorded data written up to that point will not be destroyed.

As a result, highly reliable data can be recorded even when the vehicle passes through locations where strong radio waves are present during testing.

Note that it is preferable to provide hysteresis to the comparison operation of the level comparator 40 to prevent chattering of the reset signal 110 output from the external noise In circuit 32.

(Effects) As explained above, according to the present invention, external noise caused by radio waves is extracted, erroneous storage of recorded data due to the external noise is predicted, and when the prediction is made, storage of recorded data is prohibited. As a result, it is possible to reliably prevent radio wave interference that would cause errors in data content or destroy existing data, making it possible to increase the reliability of data recorded while the vehicle is running.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration explanatory diagram showing a preferred embodiment of the device according to the present invention, FIG. 2 is a block diagram showing the configuration of a conventional device,
FIG. 3 is a signal waveform diagram for explaining the operation of the embodiment shown in FIG. 10-1.10-2・10-N...Sensor 12...
Processing circuit 20...Storage circuit 32...External noise monitoring circuit 34...High frequency detection circuit 36...Bypass filter 38...Envelope detection circuit 40...Level comparator 42...Signal delay circuit Patent applicant Nissan Motor Co., Ltd. −−1−−1σ′・
Mantan II Momme 2nd figure 3rd figure t2 ; ; (G)

Claims (1)

[Claims] (1) A state quantity detection means for detecting the state quantity of a predetermined part of the vehicle; a recorded data generation means for generating recorded data from the state quantity detection signal; a recorded data storage means for storing the recorded data; an extraneous noise extraction means for extracting mixed extraneous noise; an error memory prediction means for predicting erroneous memory of recorded data due to extraneous noise by monitoring the level of the extracted noise; A vehicle data recording device comprising: data recording prohibition means for prohibiting storage of data.