JPH05231233A - Communication device having fail safe function - Google Patents

Abstract

PURPOSE:To carry out fail safe treatment with high safety in a communication device in which fail safe treatment is done upon abnormality of a system by monitoring disconnection of each communication line in the case where data communication is performed by the use of a plurality of communication lines, and succeeding the controlling by the use of data sent from the other communication line which effectively functions when disconnection at a communication line is detected. CONSTITUTION:In the case where binarized data is parallelly transmitted between electronic control units 2 and 3, the data are invented and sent after normal sending is performed. When the data is not invented, communication lines 1a, 1b are judged to be disconnected. A fail safe treatment means 4 specifies the disconnected communication line, and selects fail safe treatment in correspondense with the condition of the disconnected line. High safety controlling is thus carried out even in abnormality of a system, based on data from a communication line which effectively functions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device having a fail-safe function, and more particularly to a communication device having a fail-safe function for detecting an abnormality when a system abnormality occurs and performing a predetermined abnormality treatment.

[0002]

2. Description of the Related Art Conventionally, predetermined processing is performed based on signals transmitted to a plurality of communication lines, and when a system malfunctions,
There is known a device for detecting an abnormality in the signal and performing an abnormality treatment (JP-A-63-295839).

In the above apparatus, the fail signal line connected to the primary coil of the ignition coil arranged corresponding to each cylinder of the internal combustion engine is connected to the primary coil of the primary coil in synchronization with the timing for igniting each cylinder. By monitoring whether the back electromotive force signal appears, disconnection of multiple primary coils is detected, and when abnormalities are detected, depending on which timing signal is missing, which cylinder The supply of fuel to the cylinder is stopped by identifying whether the primary coil is broken.

Further, in the prior art, a method of performing an abnormality treatment based on a normal signal or an abnormal signal transmitted to a fail signal line as in the above-mentioned device is used by a plurality of electronic control devices in order to perform more advanced control. 7 is also used in a device that performs parallel data communication using the signal line of FIG. 7, in which the output of the knock sensor that converts the cylinder internal pressure of the internal combustion engine into a 2-bit knock intensity signal is output from the knock sensor signal processing CPU. , Shows a time chart when transmitting to the engine control CPU.

FIG. 1A is transmitted from the engine control CPU.
Time at which the TDC (top dead center) signal is displayed and becomes the top dead center
T₁When it becomes 30 ° (ATDC30CA) after top dead center
Tick T ₃The low level signal is output only during the period. Knock
The sensor signal processing CPU switches this signal from high to low.
As shown in (E) and (F) of FIG.
The knock sensor connected to the CPU
Reverse output inversion pattern with and without
And output a fail signal.

Next, the knock sensor signal processing CPU calculates and sets a knock strength / failure judgment section starting at time T ₂ and sets time T ₄ at the end of the section in FIG. Of the knock intensity ((B) and (C) in the same figure) and whether or not there is an abnormality in the knock sensor is determined, and the knock intensity determined at the time T ₄ when the section ends is output. If it is abnormal, the fail signal is output as high, and if abnormal, it is output as low.

Therefore, the engine control CPU can determine whether or not the knock sensor is normal by the inversion pattern of the fail signal. If the fail signal is not inverted, the fail signal line is broken. Can be recognized.

[0008]

However, the fail-safe function in the above-mentioned conventional communication between a plurality of electronic control units monitors only the signal transmitted to the fail signal line to make the fail judgment. Even if only one of the communication lines input to the control unit is broken, if the fail signal determines that the system is abnormal, input from multiple communication lines as an error measure Since all the information that is processed is treated as an abnormality, it is not possible to perform detailed control in such a situation.

Further, in the case of parallel communication of binary data using a plurality of signal lines, since there is no fail-safe function for disconnection of the data lines, the transmission side electronic control unit and the reception side electronic control unit are not provided. However, there is a case where the abnormality cannot be detected, and incorrect data is continuously transmitted while the data line is broken, which is dangerous for control.

The present invention has been made in view of the above points, and when data communication is performed between a plurality of electronic control units using a plurality of communication lines, each signal transmitted to each communication line is transmitted. When an abnormality is detected individually, and when that abnormality is detected, enter the value on the safe side in the data value that should be input by that signal, and it will be transmitted from other valid communication lines. It is an object of the present invention to provide a communication device having a fail-safe function that performs highly safe abnormality handling by continuing control based on a signal indicating that the signal is present.

[0011]

In order to solve the above-mentioned problems, the device of the present invention, as shown in the principle diagram of FIG. 1, has a plurality of transmitting / receiving means 2 arranged in a plurality of electronic control devices 2, 3.
A plurality of communication lines 1 connecting between c, 2d and 3c, 3d
Communication means 1 for communicating signals in parallel using a and 1b
And abnormality detecting means 2a, 2b, 3 for individually detecting abnormality of each signal transmitted to the plurality of communication lines 1a, 1b.
When a, 3b and the abnormality detecting means 2a, 2b, 3a, 3b detect an abnormality in the signal, it is assumed that the value on the safe side is input to the data value to be input by the signal detected as the abnormality. It is the structure provided with the fail-safe treatment means 4 for treating.

[0012]

According to the above construction, the plurality of electronic control units 2,
When performing parallel communication of data between three, a plurality of communication lines 1
There is an abnormality detecting means 2a, 2b, 3a, 3b for individually detecting the abnormality of each signal transmitted to a and 1b, and a part of the signals transmitted in parallel for detecting the abnormality for each communication line. If an abnormality occurs, it is possible to identify the abnormal portion and determine that the signals transmitted by the remaining communication lines are effective for control. In addition, since the safe-side value is input to the data value that should be input by the signal of the abnormal portion, the fail-safe measure means 4 can perform control close to a normal signal and highly safe when the system is abnormal. Continued.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a circuit diagram of an embodiment of the device of the present invention. In the figure, 5 and 6 are knock sensors for converting the in-cylinder combustion pressure of the internal combustion engine into electric signals, which are connected to a knock sensor signal processing CPU 9 corresponding to the electronic control unit 2 via knock sensor signal processing circuits 7 and 8. Has been done. The knock sensor signal processing CPU 9 and the engine control CPU 16 corresponding to the electronic control unit 3 include a TDC signal line 10, a cylinder discrimination signal line 11, knock intensity signal lines 12 and 13 corresponding to the plurality of communication lines 1a and 1b, and a fail. They are connected to each other via a signal line 14 and a fail sensor signal line 15, and constitute the communication means 1 to perform mutual communication.

The respective communication lines connecting the knock sensor signal processing CPU 9 and the engine control CPU 16 will be described below. The TDC signal line 10 and the cylinder discrimination signal line 11 are transmitted from the engine control CPU 16 to the knock sensor signal processing CP.
A communication line directed to U9 transmits a top dead center signal and a cylinder discrimination signal indicating which cylinder is at the top dead center.

On the basis of these signals, the knock sensor signal processing CPU 9 selects one of the knock sensors 5 and 6 arranged in the cylinder at the top dead center to take in data,
The knock intensity is divided into four levels and engine control C is performed with a 2-bit signal using knock intensity signal lines 12 and 13.
It is being sent to PU16.

The fail signal line 14 is used when the knock sensor signal processing CPU 9 detects an abnormality in the output signals of the knock sensor signal processing circuits 7 and 8 or when no signal is input from the TDC signal line 10 and the cylinder discrimination signal line 11. , An abnormality signal issued by the knock sensor signal processing CPU 9 upon judging that the sensor system is abnormal or the communication line is broken.
The communication line to be transmitted to the fail sensor signal line 15
Is a signal indicating which system has an abnormality when the knock sensor signal processing CPU 9 detects an output abnormality of the knock sensor signal processing circuits 7 and 8 and transmits an abnormality signal to the fail signal line 14. It is a communication line for transmitting.

Since these abnormal signals represent the abnormalities by outputting the inversion pattern of the signal which is inverted in response to the TDC signal by reversing the normal pattern and the abnormal pattern, the fail signal line 14 and the fail signal line fail. When the sensor signal lines 15 are broken, the engine control CPU 16 recognizes that those signal lines are broken because the signals are not inverted.

As described above, the engine control CPU 16 of the apparatus according to the present embodiment monitors the signals of the fail signal line 14 and the fail sensor signal line 15 to detect an abnormality in the sensor system, the TDC signal line 10, and the cylinder discrimination signal line. It is possible to recognize the disconnection of each of the communication lines 11, 11, the fail signal line 14, and the fail sensor signal line 15.

The knock intensity signal lines 12 and 13 are provided in the knock sensor signal processing CPU 9 with the abnormality detecting means 2a and 2a.
An inversion output mechanism corresponding to b is provided for each communication line, and an inversion output receiving mechanism corresponding to the abnormality detecting means 3a and 3b is provided in the engine control CPU 16, and the engine control CPU 16 has the inversion output receiving mechanism. By monitoring the inversion of transmitted data, disconnection of these communication lines is detected.

Regarding the transmission and reception of the fail signal and the above 2-bit data between the knock sensor signal processing CPU 9 and the engine control CPU 16, the knock intensity signal output routine shown in FIG. 3, the knock intensity signal fetching routine shown in FIG. This will be described based on the transmission / reception time chart shown in FIG.

As shown in FIG. 5 (A), when the knock sensor signal processing CPU 9 is notified that the TDC signal transmitted from the engine control CPU 16 changes from high to low at the time t ₁ and is at the top dead center, The knock intensity inversion output routine of the knock sensor signal processing CPU 9 shown in 3 (a) is started, and the fail signal is inverted and output in step 101. Due to the above reason, this output is output with the output pattern reversed in the normal state and the abnormal state, as shown in FIGS.

Next, at step 102, as shown in FIGS. 5B and 5C, a knock intensity signal of 2-bit data is inverted and output for the same purpose, and the TDC signal is switched from low to high at time t ₃ in FIG. The output is held until it is notified that it is 30 ° after the top dead center (period in the figure). After that, because the predetermined processing is completed by the time the next top dead center is reached,
In step 103, the knock intensity and the section in which the fail determination is performed (the period in the figure) are calculated, the determination section is set (step 104), and the inversion output routine ends.

At time t ₂ in the figure, a timer interruption starts a knock intensity / failure determination section as shown in FIG. 3 (D), and the calculation routine shown in FIG. 3 (b) is started. Process, step 1
Until the TDC signal is determined to be high in 06, the processing is continued without outputting the calculation result in order to gain time to hold the inverted output of the knock intensity (period in the figure).

At time t ₃ in FIG. 5, as shown in FIG.
When the engine control CPU finishes loading the knock intensity, T
In response to switching the DC signal from low to high, the routine proceeds to step 107, where the calculated knock intensity signal is output, and step 1 is performed until it is determined at step 108 that the determination section ends.
When the knock strength / failure judgment section set at time t ₄ is completed by repeating the calculation and the output at any time (the period in the figure), the operation proceeds to step 109 while the confirmed knock strength is output and the knock signal is normal. It is determined whether or not there is.

If the knock signal is normal, a high level is output to the fail signal in step 110 as shown in FIG.
If it is abnormal, a low is output in step 111 as shown in FIG. 11F, and the output is held and the process ends until the time T ₅ becomes top dead center again and the next cycle starts.

In the knock intensity signal fetching routine in the engine control CPU 16, as shown in FIG. 4, it is determined in step 121 whether it is 30 ° after top dead center, and it is determined that it is not 30 ° after top dead center. In this case, the process proceeds to step 122 and it is determined whether or not it is the top dead center.

As shown in FIGS. 5G and 5H, since the fail signal and the knock intensity signal are taken in by the engine control CPU only at the top dead center and at 30 ° after the top dead center, the top dead center is not determined in step 122. When the determination is made, the processing is finished as it is.

When it is determined that it is the top dead center at time t ₁ in the figure (step 122), (E) to (H) in the figure.
As shown in FIG. 6, before switching the TDC signal from high to low, the fail signal output as high when the system is normal and the low knock strength signal when the system is abnormal and the confirmed knock intensity signal are fetched (step 123, step 12).
4) Next, in order to notify the knock sensor signal processing CPU 9 that it is at top dead center, the TDC signal is switched from high to low and output (step 125), and the capture processing at top dead center is completed.

Next, at time t ₃ in the figure, 30 after the top dead center.
If it is determined that the angle is 0 ° (step 121), the process proceeds to step 126, the fail signal after the inversion is taken in, and then the knock intensity signal similarly similarly inverted is taken in at step 127, then the process proceeds to step 128, and the knock sensor signal is obtained. In order to notify the processing CPU 9 that it is 30 ° after top dead center, the TDC signal is switched from low to high and output.

As described above, the signal taken in by the engine control CPU 16 at the top dead center is always the fail signal and knock intensity signal before inversion, and the signal taken in at 30 ° after the top dead center is always the fail signal and knock intensity signal after inversion. Become.
Therefore, by comparing these signals, not only the abnormality detected by the fail signal but also the disconnection or communication abnormality of the fail signal line and the knock intensity signal line can be detected.

As described above, when the knock strength signal lines 12 and 13 are broken, the apparatus according to the present embodiment can individually detect the abnormality, and therefore, in step 129, it is determined whether or not there is an abnormality in the fail signal system. If it is determined that there is an abnormality, fail processing is performed according to the fail signal (step 13).
0) Although the processing is ended, if normal, the routine proceeds to step 131, where it is also judged whether or not the knock intensity signal is normal.
If the knock intensity signal is normal, the knock intensity is set in the arithmetic unit in the engine control CPU 16 for use in control (step 132), and if it is determined to be abnormal, the step 133 corresponding to the fail-safe measure means 4 is performed. Then, the process proceeds to step S21 and performs an abnormality process according to the abnormality of the knock intensity signal, and ends the process.

This abnormality processing will be described below with reference to FIG. In FIG. 6 (A), the knock sensor signal processing CPU 9 according to the present embodiment has knock sensor signal processing circuits 7 and 8.
The outputs of the knock intensity signal lines 12 and 13 when the in-cylinder knock intensity of the internal combustion engine is divided into four levels based on the signal input from Here, the knock level represents the lowest knock intensity K0 and the highest knock intensity K3, and the engine control CPU 16 calculates the ignition retard amount based on this output.

As shown in the figure, the knock strength signal line 12 outputs the data value of the knock strengths K0 and K1 during normal output.
The data value "0" is output with 1 "and knock strength K2, K3, and these are inverted and output at the time of inverted output. Therefore, when the knock strength signal line 13 is disconnected, the engine control C
PU16 has in-cylinder knock strength of K0, K1 group and K
It can be divided into 2 and K3 groups.

When the detected knock intensity level is lower than a predetermined level, the engine control CPU 16 increases the knock intensity by decreasing the retard amount in order to increase the output of the internal combustion engine. When the value is higher than a predetermined level, the retard amount is increased and the knock strength is weakened to prevent knocking.
When the knock intensity recognized by is weaker than the knock intensity generated in the cylinder, the retard amount is controlled to be smaller,
There is a risk of inducing knocking, discharging incomplete combustion gas, and damaging the catalyst.

Therefore, in the device according to the present embodiment, when the knock strength signal line 13 is broken, the engine control CP
When the in-cylinder knock intensity is K0 or K1 based on the output of the knock intensity signal line 12, U16 determines that it has received the K1 signal indicating the high knock intensity level, and the knock intensity is K2 or K3. If it is recognized, it is determined to be K3. For the same reason, knock strength signal line 1
When the wire No. 2 is disconnected, the knock strength is determined based on the output of the knock strength signal line 13 into two levels of K2 and K3, and the control is performed. As described above, the device according to the present embodiment is based on the 1-bit signal input from the remaining one knock intensity signal line even if one of the knock intensity signal lines 12 and 13 transmitting the 2-bit signal is disconnected. And highly safe control can be continued.

FIG. 6B shows the knock intensity signal line abnormality treatment routine. In order to confirm the state of the knock intensity signal line, it is determined in step 141 whether or not the knock intensity signal line 12 is normal, and if normal, the same determination is made for the knock intensity signal line 13 in step 142. If it is determined to be normal, the process proceeds to step 143,
Knock strength engine control CP to perform normal processing
It is set in the operation unit in U16, and the process ends.

When it is determined in step 142 that the knock intensity signal line 13 is abnormal, the control proceeds to step 144 because the control is performed only by the output of the knock intensity signal line 12, and the knock intensity is set to K1 and K3 for the above reason. Judge in two stages,
It is set in the arithmetic unit in the engine control CPU 16 and the process is terminated.

In step 141, knock strength signal line 12
Is determined to be abnormal, it is similarly determined in step 145 whether or not the knock intensity signal line 13 is normal, and if normal, control is continued with the 1-bit signal of this knock intensity signal line 13. To do so, the routine proceeds to step 146, where the knock intensity determined in two steps of the knock intensity K2 and K3 is set in the arithmetic unit in the engine control CPU 16 and the process is terminated.

If it is determined in step 145 that the knock intensity signal line 13 is also abnormal, both knock intensity signal lines 12 and 13 are abnormal, and all the knock intensity signals input to the engine control CPU 16 are abnormal signals. Therefore, it is determined that the knock strength is K3 to prevent knocking,
Control is performed to retard the position where knocking does not occur, and the processing ends.

As described above, the apparatus according to the present embodiment individually detects the abnormality of the knock intensity signal lines 12 and 13 in addition to the abnormality recognized by the signals transmitted by the fail signal line 14 and the fail sensor signal line 15. Then, since the control is performed in the region where knocking does not occur depending on the mode of the abnormality, highly safe control can be performed even when the system is abnormal.

In the present embodiment, a device for performing knock intensity signal communication is described as a device having a fail-safe function, but the device is not limited to this.
Any device that performs data communication in parallel using a plurality of communication lines and performs predetermined control based on the data may be used.

[0042]

As described above, according to the present invention, when data communication is performed between a plurality of electronic control units by using a plurality of communication lines, a signal transmitted is monitored for each communication line. The anomaly is detected individually, and when an anomaly is detected, the value for safe control is substituted into the data value that should be transmitted by that communication line, and other valid communication is performed. Since the control based on the data transmitted from the line is continued, it is possible to execute the abnormal measures that perform highly precise and detailed control even when the system is abnormal, and minimize the influence of disconnection of the communication line. It can be stopped hard. .

[Brief description of drawings]

FIG. 1 is a principle view of the device of the present invention.

FIG. 2 is a circuit configuration diagram of an embodiment of the device of the present invention.

FIG. 3 is a knock intensity signal output routine of one embodiment of the device of the present invention.

FIG. 4 is a knock intensity signal fetching routine of one embodiment of the device of the present invention.

FIG. 5 is a transmission / reception time chart between electronic control devices of one embodiment of the device of the present invention.

FIG. 6 is an output example of a knock intensity signal and an abnormality treatment routine of a knock intensity signal line in one embodiment of the device of the present invention.

FIG. 7 is a transmission / reception time chart between electronic control devices of a conventional device.

[Explanation of symbols]

 1 Communication Means 1a, 1b Communication Lines 2, 3 Electronic Control Units 2a, 2b, 3a, 3b Abnormality Detection Means 4 Fail Safe Execution Means 9 Knock Sensor Signal Processing CPUs 12, 13 Knock Strength Signal Lines 14 Fail Signal Lines 16 Engine Control CPU

Claims (1)

[Claims] 1. A communication means for communicating signals in parallel using a plurality of communication lines connecting a plurality of transmission / reception means arranged in a plurality of electronic control devices, and each of the communication means being transmitted to the plurality of communication lines. Abnormality detecting means for individually detecting the abnormality of the signal of the signal, and when the abnormality detecting means detects the abnormality of the signal, the value on the safe side is input to the data value to be input by the signal detected as the abnormality. A communication device having a fail-safe function, comprising: a fail-safe treatment means for treating as a thing.