JP7189853B2 - vehicle control system - Google Patents

Description

The present invention relates to a vehicle control system including a vehicle control device having an output terminal for outputting an analog voltage signal.

Patent Document 1 discloses a serial communication method in which only one wire is used between transmission and reception to sequentially transmit data bit by bit. A serial communication method is disclosed in which a predetermined number n of bit data is transmitted between one and the next synchronous trigger signal.

JP 2003-273942 A

By the way, if a vehicle control device such as a sensor control IC that outputs an analog voltage can transmit information about a specific state such as a failure state to an external device via a signal line for analog voltage output, the system While preventing the configuration from becoming complicated, the specific state of the vehicle control device can be grasped from the outside, and the functionality of the system is improved.
However, if it is necessary to separately transmit a synchronization signal (synchronization trigger signal) in order to synchronize communication between a vehicle control device such as a sensor control IC and an external device, the information transmission/reception processing becomes complicated. Moreover, when the signal waveform output by the vehicle control device is displayed on the screen of the waveform measuring instrument, there is a problem that the operator cannot easily identify the signal visually.

The present invention has been made in view of the conventional circumstances, and its object is to transmit and receive information with a simple configuration when transmitting information through a signal line for analog voltage output in a specific state, Another object of the present invention is to provide a vehicle control system capable of easily identifying signal waveforms on a screen.

Therefore , as one aspect of the vehicle control system according to the present invention, there is provided a vehicle control device having an output terminal for outputting an analog voltage signal, wherein in a specific state of the vehicle control device, information about the specific state is provided. the vehicle control device , which converts the pulse signal into a pulse width in a predetermined pulse period, and outputs the pulse signal of the predetermined pulse period and the pulse width from the output terminal in place of the analog voltage signal ; and a second vehicle control device connected by a signal line , wherein the pulse signal is a signal that falls every predetermined pulse period or a signal that falls every predetermined pulse period. The second vehicle control device also serves as a synchronous trigger signal, and the second vehicle control device compares the amount of change per unit time of the output from the output terminal with a threshold value, and reads the analog voltage signal. switching from the pulse signal reading process, and in the pulse signal reading process, when the pulse signal is a signal that falls at each of the predetermined pulse cycles, the rising edge of the pulse signal is set as a synchronous trigger signal; is a signal that rises every predetermined pulse period, the signal is read out using the rise of the pulse signal as a synchronous trigger signal.

According to the above invention, information can be transmitted and received with a simple configuration, and signal waveforms can be easily identified on the screen.

1 is a schematic diagram showing one aspect of a vehicle control system; FIG. 4 is a time chart showing one aspect of the configuration of a pulse signal PS; 4 is a flowchart showing a process of switching output between analog voltage signal AVS and pulse signal PS; 4 is a flow chart showing switching between read processing for the analog voltage signal AVS and read processing for the pulse signal PS;

Embodiments of the present invention will be described below.
FIG. 1 shows a vehicle control system 200 mounted on a vehicle 100. As shown in FIG.
The vehicle control system 200 includes an electronic control unit 20 that controls an in-vehicle machine 10 such as an engine as a power source of the vehicle 100, and a sensor control IC 30 that is one aspect of the vehicle control device according to the present invention.
The sensor control IC 30 detects physical quantities such as pressure and temperature that indicate the operating state of the in-vehicle machine 10, and the electronic control unit 20 performs arithmetic processing based on the physical quantities detected by the sensor control IC 30 to generate a control signal for the in-vehicle machine 10 ( manipulated variable).

The sensor control IC 30 includes a sensor unit 31 that generates outputs according to physical quantities such as pressure and temperature, a microcomputer 32 that includes an MPU (Microprocessor Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. It has an output terminal 33 for outputting an analog voltage signal AVS as a sensor output (pressure or temperature detection signal).
The microcomputer 32 of the sensor control IC 30 controls the operation of the sensor section 31 and also sets the voltage level of the analog voltage signal AVS output from the output terminal 33 .

Further, the microcomputer 32 of the sensor control IC 30 has a self-diagnosis function as software, and has a normal operation mode and a test mode as operation modes.
The physical quantity detected by the sensor unit 31 is not limited to the above pressure and temperature, and may be fluid flow rate, angle, distance, and the like.

Also, the sensor control IC 30 can include a plurality of sensor units 31 .
Further, the sensor control IC 30 having the microcomputer 32 and the output terminal 33 and the sensor section 31 can be configured separately.

On the other hand, the electronic control unit 20, which is one aspect of the second vehicle control device according to the present invention, includes an input terminal 21 connected to the output terminal 33 of the sensor control IC 30 by one signal line 40, an MPU, a ROM, A microcomputer 22 having a RAM and the like and an output terminal 23 for outputting a control signal for the in-vehicle machine 10 are provided.
The microcomputer 22 of the electronic control unit 20 acquires the analog voltage signal AVS output by the microcomputer 32 of the sensor control IC 30 via the input terminal 21, and based on the physical quantity represented by the voltage level of the analog voltage signal AVS, the in-vehicle machine 10 and outputs the calculated control signal from the output terminal 23 to the in-vehicle machine 10 .

The sensor control IC 30 has an output terminal 33 and a signal line 40 for outputting an analog voltage signal AVS (in other words, an analog sensor output signal) in a specific state such as a failure state or test mode that is different from the normal operating state. It is used to provide a communication signal output that transmits encoded information regarding fault conditions, test modes, etc. to the electronic control unit 20 .
In the above communication signal output, the sensor control IC 30 converts encoded information about a specific state such as a failure state or test mode into a pulse width PW in a predetermined pulse period PC, and converts the predetermined pulse period PC and pulse width PW is output from the output terminal 23 as a communication signal in place of the analog voltage signal AVS.

Here, the rise or fall of the pulse signal PS with a predetermined pulse period PC and pulse width PW serves as a synchronization trigger signal with a constant period, and the electronic control unit 20 on the receiving side determines the readout timing of the pulse signal PS. Judgment is made based on the rise or fall of
That is, the pulse signal PS having a predetermined pulse period PC and pulse width PW is a signal that also serves as a synchronous trigger signal, and the sensor control IC 30 electronically controls the synchronous trigger signal through a signal line provided separately from the signal line 40. Rather than needing to be sent separately to unit 20, the information about the specific state can be sent to electronic control unit 20 directly using the transmission path of analog voltage signal AVS.

FIG. 2 shows one aspect of the configuration of the pulse signal PS.
The pulse signal PS in FIG. 2 is composed of a header, bit data (0 or 1), footer, and data delimiter, which are distinguished from each other by the pulse width PW.
Here, the pulse width PW of each of the header, bit data, footer, and data delimiter is set, for example, as follows when expressed as the ratio of the high period and the low period in the pulse period PC.

Header: "100% High + 50% Low, 50% High"
1 (High) ... "25% Low, 75% High"
0 (Low) ... "75% Low, 25% High"
Footer ... "50% Low, 50% High"
Data separator: "50% Low, 50% High"
Here, the pulse signal PS represents 1 bit with two different pulse widths PW of 25% Low, 75% High and 75% Low, 25% High, and 1 bit data can be transmitted for each pulse period PC. , 256 numbers can be represented by transmitting 8-bit data.

Therefore, for example, when the sensor control IC 30 diagnoses a failure state by self-diagnosis, information about the failure state such as information indicating the occurrence of the failure, the location of the failure, and information indicating the failure pattern is encoded into a numerical value that can be expressed in 8 bits. A pulse signal PS representing the numerical value is generated by allocating the pulse width PW for each pulse period PC, and is output to the electronic control unit 20 via the output terminal 33 .
When the sensor control IC 30 is set to the test mode, the sensor control IC 30 encodes information about the test pattern into a numerical value that can be expressed in 8 bits, and assigns a pulse width PW for each pulse period PC to the pulse signal PS that expresses the numerical value. is generated and output to the electronic control unit 20 via the output terminal 33 .

On the other hand, the electronic control unit 20 recognizes the numerical value represented by 8 bits by determining the pulse width PW using the rise of the pulse signal PS as a synchronous trigger signal, and the information about the failure state transmitted from the sensor control IC 30 and the , information about the test mode such as the test pattern.
The pulse width PW of the header, bit data, footer, and data delimiter can be set arbitrarily, and the rise of the pulse signal PS can obviously be a synchronous trigger signal.

In the test mode, the sensor control IC 30 connects the output terminal 33 and the input terminal of a waveform measuring instrument such as an oscilloscope, and the pulse signal PS output by the sensor control IC 30 can be displayed on the screen of the waveform measuring instrument. can.
In this case, the pulse signal PS displayed on the screen of the waveform measuring instrument has a constant pulse cycle PC and a pulse width PW (100% High, 75% High, 50% High, 25% High) in combination to represent bit data along with headers and footers.
Therefore, the operator can easily read the information (the information about the failure state and the information about the test mode) output by the sensor control IC 30 by viewing the waveform on the screen of the waveform measuring instrument.

FIG. 3 is a flowchart showing a process of output switching between analog voltage signal AVS (sensor output signal) and pulse signal PS by sensor control IC 30 .
First, in step S501, the sensor control IC 30 determines whether or not the state is normal, and if the state is normal, the process proceeds to step S502.
The sensor control IC 30 outputs the analog voltage signal AVS (sensor output signal) from the output terminal 33 in step S502.

On the other hand, when the sensor control IC 30 determines that the normal state is not in step S501, the process proceeds to step S503.
In step S503, the sensor control IC 30 determines whether or not there is a specific state such as a failure state diagnosed by self-diagnosis or a state in which the test mode is set.

When the sensor control IC 30 is in a specific state such as a failure state or a test mode, the process proceeds from step S503 to step S504, and the pulse signal PS representing information about the specific state is output from the output terminal 33 instead of the analog voltage signal AVS. do.
The information about the specific state is information about the failure state in the failure state, and information about the test mode in the test mode.

Here, when the analog voltage signal AVS has an output range of, for example, 0 V to 5 V and the analog voltage signal AVS does not stick to 0 V or 5 V in a normal state, the sensor control IC 30 sets the pulse signal PS to low. A voltage range from level to high level is assumed to be, for example, a range from 1 V to 4 V (low level=1 V, high level=4 V) included in the output range of the analog voltage signal AVS.
As a result, when the pulse signal PS is output from the output terminal 33 of the sensor control IC 30 in a specific state, it is possible to prevent the output of the output terminal 33 from sticking to 0 V or 5 V and diagnosing it as an abnormal voltage by the monitoring program. .

Further, the electronic control unit 20, which receives the signal output from the output terminal 33 of the sensor control IC 30, converts the output of the sensor control IC 30 into an analog voltage signal AVS based on the amount of voltage change per unit time of the output signal from the output terminal 33. or the pulse signal PS to switch the processing.
That is, when the amount of voltage change per unit time of the output signal from the output terminal 33 is equal to or greater than the threshold value, the electronic control unit 20 regards the output of the sensor control IC 30 as the pulse signal PS, and for example, sets the trailing edge as the synchronization trigger signal. The signal is read out as

On the other hand, the electronic control unit 20 processes the output of the sensor control IC 30 as an analog voltage signal AVS when the amount of voltage change per unit time of the output signal from the output terminal 33 is below the threshold.
When the analog voltage signal AVS is a pressure or temperature detection signal, the amount of change per unit time of the analog voltage signal AVS is sufficiently smaller than that of the pulse signal PS. By comparing with the threshold value, it is possible to determine whether the input signal is the analog voltage signal AVS or the pulse signal PS and switch the processing.

FIG. 4 is a flow chart showing switching of reading processing in the electronic control unit 20 .
In step S601, the electronic control unit 20 calculates a voltage change amount ΔV of the voltage signal received from the sensor control IC 30 per unit time.

Next, in step S602, the electronic control unit 20 compares the absolute value of the voltage variation ΔV with the threshold THV. is the pulse signal PS, and reading processing for the pulse signal PS is performed in step S603.
That is, in step S603, the electronic control unit 20, for example, reads the signal using the fall of the pulse signal PS as the synchronization trigger signal.

On the other hand, when the absolute value of the voltage change amount ΔV is below the threshold value THV, the electronic control unit 20 determines that the voltage signal received from the sensor control IC 30 is the analog voltage signal AVS indicating the detected pressure or temperature value. Then, in step S604, read processing for the analog voltage signal AVS is performed.
That is, in step S604, the electronic control unit 20, for example, obtains the detected values of pressure and temperature from the A/D converted value of the analog voltage signal AVS, and calculates the control signal for the in-vehicle machine 10 based on the obtained detected values. Output.

Each of the technical ideas described in the above embodiments can be used in appropriate combination as long as there is no contradiction.
Although the content of the present invention has been specifically described with reference to preferred embodiments, it is obvious that those skilled in the art can make various modifications based on the basic technical idea and teaching of the present invention. is.

For example, the vehicle control device according to the present invention is not limited to the sensor control IC 30, and may be any vehicle control device that outputs an analog voltage signal AVS in a normal state.
Further, the second vehicle control device is not limited to a device that directly controls the in-vehicle machine 10, and may be, for example, a device that outputs a control target and a control command to another vehicle control device.

Further, the specific state of the vehicle control device is not limited to the failure state or test mode.
For example, in a vehicle control device that normally outputs an analog voltage signal AVS and occasionally outputs a pulse signal PS representing predetermined information, the output timing of the pulse signal PS, such as every predetermined period, can be set to a specific state.
In other words, the fact that the vehicle control device outputs the pulse signal PS less frequently than the analog voltage signal AVS corresponds to outputting the pulse signal PS in a specific state.

20... Electronic control unit (second vehicle control device), 30... Sensor control IC (vehicle control device), 31... Sensor section, 32... Microcomputer, 33... Output terminal, 40... Signal line, 100... Vehicle, 200 Vehicle control system

Claims (6)

A vehicle control device comprising an output terminal that outputs an analog voltage signal,
In a specific state of the vehicle control device, the information about the specific state is converted into a pulse width in a predetermined pulse period, and the pulse signal with the predetermined pulse period and the pulse width is output instead of the analog voltage signal. output from the terminal,
the vehicle control device;
a second vehicle control device connected to the output terminal by a signal line;
A vehicle control system comprising:
the pulse signal is a signal that falls every predetermined pulse period or a signal that falls every predetermined pulse period and also serves as a synchronization trigger signal;
The second vehicle control device includes:
comparing the amount of change per unit time of the output from the output terminal with a threshold to switch between reading processing of the analog voltage signal and reading processing of the pulse signal ;
In the reading process of the pulse signal, when the pulse signal is a signal that falls every predetermined pulse period, the rising edge of the pulse signal is used as a synchronous trigger signal, and the pulse signal is a signal that rises every predetermined pulse period. when the signal is read using the rise of the pulse signal as a synchronous trigger signal,
vehicle control system. A vehicle control system according to claim 1,
The pulse signal includes a header, bit data, and footer,
the bit data represents one bit with two different pulse widths;
vehicle control system. A vehicle control system according to claim 1,
diagnosing abnormal voltage when the voltage of the output terminal sticks to the limit value of the voltage range of the analog voltage signal;
The vehicle control device includes:
The voltage range of the pulse signal is a range included in the voltage range of the analog voltage signal ;
vehicle control system. A vehicle control system according to claim 1,
The analog voltage signal is an output signal of a sensor that detects a physical quantity indicating the operating state of the in-vehicle machine .
vehicle control system. A vehicle control system according to claim 1,
The vehicle control device includes:
When a failure state is detected by self-diagnosis, the information about the failure state is converted into the pulse width, and the pulse signal having the predetermined pulse period and the pulse width is output from the output terminal instead of the analog voltage signal. do,
vehicle control system. A vehicle control system according to claim 1,
The vehicle control device includes:
When the specific state is the test mode, the information about the test mode is converted into the pulse width, and the pulse signal having the predetermined pulse period and the pulse width is output from the output terminal instead of the analog voltage signal. do,
vehicle control system.

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