JP4866214B2 - Control unit and in-vehicle multiple communication system - Google Patents

Description

  The present invention relates to a control unit and a multiplex communication system including the control unit, and in particular, in a control unit connected to a plurality of control units via a multiplex communication line, a low power consumption state of the control unit when the engine is stopped It is intended to promote the transition to, to reduce battery consumption and prevent the battery from running out.

In recent years, the number of electrical components and electrical devices mounted on a vehicle has increased rapidly as the functions and performance of the vehicle have increased, and the wiring in the vehicle has become more complex and larger.
Therefore, in order to suppress an increase in the number of wirings in the vehicle, a multiplex communication system that reduces the number of wirings by connecting control units (hereinafter referred to as ECUs) for controlling in-vehicle electrical components with multiplex communication lines is being adopted. .

  In the above-described multiplex communication system, when an ECU for controlling an on-vehicle electrical component (for example, a room light) that operates even when the engine is stopped is connected to the ECU, power supply from the battery is continued. However, since the battery is not charged when the engine is stopped, it becomes a factor that the battery runs out.

Normally, an in-vehicle ECU has a function for shifting to a high power consumption mode of a wakeup mode (normal operation mode) and a low power consumption mode of a sleep mode, and needs to be in a wakeup mode when the engine is stopped. An ECU that does not have a transition to sleep mode reduces power consumed by the ECU.
However, when the ECU is connected via the multiplex communication line to form a multiplex communication system, the transition from the wake-up mode to the sleep mode is a cooperative operation of all ECUs. Therefore, when the ECU enters the sleep mode enabled state, it notifies other ECUs connected to the multiplex communication system, and after all the ECUs enter the sleep shift enabled state, all the ECUs in the multiplex communication system are in the sleep state. It becomes a system that can be transferred to.

  At this time, if there is an ECU that cannot be shifted to the sleep mode and continues to operate in the wake-up mode due to a vehicle state or a failure of the ECU, the multiplex communication system to which the ECU is connected shifts to the sleep mode. There is a problem that can not be. As a result, the supply of power to all ECUs in the multiplex communication system must be continued, and the above-described problem of battery exhaustion occurs.

  In order to solve the above problem, Japanese Patent Laid-Open No. 2005-20570 (Patent Document 1) gives each ECU a function of forcibly shifting itself to the sleep mode, and the ignition switch ON / OFF detection means detects OFF. If the engine is determined to have stopped and the battery voltage is detected and the battery voltage drops below the specified value, the ECU operating in the wake-up mode is forced to shift itself to the sleep mode. Is provided. By providing each ECU with the functions described above, even if there is an ECU that cannot be shifted to the sleep mode among ECUs connected by multiple communication lines, the on / off detection means of the ignition switch detects the off and the engine is stopped. If it is determined, all ECUs in the multiple communication system, including the ECU that cannot shift to the sleep mode, shift to the sleep mode.

JP 2005-20570 A

  However, the method of Patent Document 1 has a problem that when the on / off detection means of the ignition switch fails, the stop of the engine is not correctly detected, and the ECU shifts to the sleep mode at an incorrect timing. For example, when the ignition power supply fuse is blown, the ignition power supply detection circuit is opened and the ignition switch is always detected to be off, and it is determined that the engine is stopped. For this reason, even when the multiplex communication system has to operate in the wake-up mode, there is a problem in that it shifts to the sleep mode.

  The present invention has been made in view of the above problems, and in an in-vehicle multiplex communication system connected to a plurality of control units via a multiplex communication line, the engine is stopped without providing an ignition switch on / off detection means. Even if there is an ECU that continues to operate in the wake-up mode without being able to shift to the sleep mode due to the state of the vehicle or the failure of the ECU, the battery consumption is reduced to prevent the battery from running out. It is an issue.

In order to solve the above problems, the present invention is a control unit connected to a plurality of other control units via multiple communication lines,
A transition determination unit that determines whether or not transition from the high power consumption state operation mode to the low power consumption state sleep mode is possible, and outputs either a sleep transition enable signal or a sleep transition disable signal;
A transmission unit that periodically transmits either of the sleep transition enable signal and the sleep transition disable signal from the transition determination unit to the other control units;
A receiver for receiving either periodically in the sleep transition enable signal and the sleep transition disable signal from all other of the plurality of control units connected through the multiplex communication line,
While it is determined that the shifting-to-sleep mode disabling by the archive determining section receives the entire Heck et the sleep transition enable signal of the other of the plurality of control units, a processing unit for forcibly shift to the sleep mode after the setting time has elapsed ,
A control unit is provided.

Normally, when the engine is running and the battery is charged, each control unit is always in wake-up mode, but when the engine stops, all control units connected to the multiplex communication line finish their processing. Transition to sleep mode is possible.
At this time, among a plurality of control units connected to the multiplex communication line, only one control unit cannot shift to sleep due to a vehicle condition or failure, but all other control units can shift to sleep. There is a case.
In the above case, in the present invention, the control unit that cannot shift to sleep receives a signal that can shift to sleep from all other control units, and when the state continues for a set time or longer, the control unit that cannot shift to sleep is Judgment that the engine is already stopped but the self is out of order and cannot enter sleep mode, and can be forced to enter sleep mode. As a result, all control units connected to multiple communication lines Can be shifted to sleep mode.

In the above configuration, the sleep shift enable signal from another control unit connected to the multiplex communication line is regarded as an engine stop signal, and the self is forcibly shifted to the sleep mode. Therefore, the engine stop can be detected without providing an ignition switch on / off detecting means. Therefore, the engine stop can be detected without being affected by the failure of the on / off detection means, and the configuration of the multiplex communication system can be simplified.
Further, by detecting the engine stop by the above-described method, even if there is a control unit in the multiplex communication system that cannot shift to the sleep mode due to a vehicle state or failure, the control unit is forcibly set. By shifting to the sleep mode, battery consumption can be reduced to prevent the battery from running out.

  The receiving unit receives a battery voltage signal from a battery monitoring unit connected to the multiplex communication line, and the processing unit is configured to elapse the set time when the battery voltage is equal to or lower than a reference value stored in a storage unit in advance. It may be set to forcibly shift to the sleep mode before.

That is, in Patent Document 1, both of the ignition switch on / off detection means and the battery monitoring means are connected to the control unit. However, in the present invention, the ignition switch on / off detection means is not required, but the battery monitoring means It may be connected to each control unit.
In this case, when it is detected that the battery voltage signal from the battery monitoring means is below the reference value, after receiving the sleep transition signal from all other control units (in other words, after detecting the stop of the engine) ), The control unit is forcibly shifted to the sleep mode without waiting for the set time to elapse. With this configuration, power supply to all the control units is not continued until the set time elapses, so that battery consumption can be further reduced and battery exhaustion can be effectively prevented.

As a second invention, there is provided a multiplex communication system characterized in that all of a plurality of control units connected via a multiplex communication line are control units having the above-described configuration.
According to the above configuration, all the control units connected via the multiplex communication line can know whether the other control units can shift to sleep or not. For example, when there is a control unit that continues to operate in the wake-up mode without shifting to the sleep transition enable state, the sleep mode can be forcibly shifted. Therefore, the battery consumption of the control unit in the multiplex communication system can be reduced.

As described above, according to the control unit of the present invention, the stop of the engine is detected by the sleep shift enable signal from another control unit connected to the multiplex communication line, and the self is forced to shift to the sleep mode. Therefore, it is possible to detect the engine stop without providing the ignition switch on / off detection means. For this reason, the engine stop can be detected without being affected by the failure of the on / off detection means, and it is not necessary to connect to the on / off detection means of the ignition switch, so that the configuration of the multiplex communication system can be simplified.
Further, by detecting the engine stop by the above method, even if there is a control unit that cannot enter the sleep mode in the multiplex communication system, the control unit is forced to enter the sleep mode and the battery consumption Can be reduced to prevent the battery from running out.
In addition, according to the second invention, it is possible to realize a multiplex communication system that reduces battery consumption and prevents the battery from running out.

Embodiments of the present invention will be described with reference to the drawings.
1 to 3 show a first embodiment of the present invention.
FIG. 1 shows a multiplex communication system 10 installed in an automobile. The multiplex communication system 10 forms a network by connecting ECUs 20 (20 </ b> A to 20 </ b> D) that control electrical components mounted on an automobile via a multiplex communication line 30. The ECUs 20 connected via the multiplex communication line 30 exchange signals with each other.
In the present embodiment, four ECUs 20A to 20D are connected in one network, but the number of connected ECUs is not limited.
In addition, the multiplex communication system 10 of this embodiment is connected in a bus type, the CAN protocol is used as the communication protocol, the access method is CSMA / CA, and the maximum communication speed is 1 Mbps.

A battery (not shown) is connected to each ECU 20, and electric power for driving each ECU 20 is supplied from the battery.
All ECUs 20 connected to the multiplex communication system 10 have a self-function that switches between two types of modes: a wake-up mode (high power consumption state) and a sleep mode (low power consumption state).

  Each ECU 20 determines whether it should operate in the wake-up mode or whether it can shift to the sleep mode, and when each ECU 20 executes its own processing and mutually transmits and receives signals, it operates in the wake-up mode, When there is no process to be executed and signals are not transmitted / received to / from each other, the sleep mode can be entered.

  Further, each ECU 20 periodically determines whether it can shift to the sleep mode, and if it can shift to the sleep mode, the ECU 20 sends the sleep shift enable signal SA via the multiplex communication line 30 in the same network. It transmits periodically to other ECU20. Similarly, when the mode cannot be shifted to the sleep mode, the sleep shift disable signal SB is transmitted to the other ECU 20 via the multiplex communication line 30.

The plurality of ECUs 20 (20A to 20D) connected by the multiplex communication line 30 simultaneously shift from the wake-up mode to the sleep mode, and from the sleep mode to the wake-up mode. Perform cooperative operation in the same mode.
For example, in the multiplex communication system 10, when any of the ECUs 20A to 20D enters the sleep-enabled state, the ECUs 20A to 20D shift to the sleep mode. Is not allowed to enter sleep mode.

  Each ECU 20 includes an I / F unit 21 serving as a communication interface with the multiplex communication line 30, a transition determination unit 22 that determines whether transition from the wake-up mode to the sleep mode is possible, and an I / F unit 21. A receiving unit 23 for receiving a signal from the connected multiplex communication line 30; a transmitting unit 24 for transmitting a signal to the multiplex communication line 30; a processing unit 25; a timer unit 26 for measuring time; A storage unit 27 for storing the set time is provided.

The receiving unit 23 periodically receives either the sleep shift enable signal SA or the sleep shift disable signal SB from all other ECUs 20.
The transmission unit 24 periodically transmits either the sleep shift enable signal SA or the sleep shift disable signal SB to all other ECUs 20.
The transition determination unit 22 determines whether or not it can transition from the wake-up mode to the sleep mode. Further, it is connected to the transmission unit 24 and periodically transmits either its own sleep transition enable signal SA or sleep shift disable signal SB via the transmission unit 24.
The processing unit 25 is connected to the transition determination unit 22 and periodically receives one of its own sleep transition enable signal SA and sleep transition disabling signal SB, and is connected to the reception unit 23 from all other ECUs 20. The sleep shift enable signal SA and the sleep shift disable signal SB are received. Under a predetermined condition, the self is forcibly shifted to the sleep mode.

The operation of the ECU 20 will be described with reference to the flowchart of FIG.
In step S10, when the processing unit 25 has received the sleep shift enable signal SA from all other ECUs 20 via the receiving unit 23, the process proceeds to S20. If even one sleep transition impossibility signal SB is received, step S10 is repeated.
In step S20, the transition determination unit 22 determines whether or not its own ECU 20 can transition to the sleep mode. If the sleep mode cannot be entered, the process proceeds to S30. If it is possible to shift to the sleep mode, the other ECUs 20 can also shift to the sleep mode, so the process proceeds to S80 and shifts to the sleep mode.
In step S <b> 30, the transmission unit 24 transmits the sleep transition impossibility signal SB to the other ECU 20 via the multiple communication line 30.

In step S40, the timer unit 26 starts measuring time.
In step S50, it is determined whether or not the set time stored in the storage unit 27 has elapsed. If the set time has elapsed, the process proceeds to step S60, and if not, step S50 is repeated.
In step S60, the transition determination unit 22 determines that it cannot shift to sleep, while it has received the sleep shift enable signal SA from all other ECUs 20, and therefore determines that the battery has stopped, The processing unit 25 can forcibly shift itself to the sleep mode.
In step S <b> 70, the processing unit 25 transmits a sleep shift enable signal SA to the other ECU 20 via the transmission unit 24.
In step S80, the processing unit 25 shifts itself to the sleep mode.

As described above, in the present invention, when the sleep shift enable signal SA is received from the other ECU 20 connected to the multiplex communication line 30, it is detected that the engine has been stopped and the sleep shift disabled state is detected. However, the state is forcibly shifted to the sleep shift enabled state, and all the ECUs are shifted to the sleep mode after a set time has elapsed since all the ECUs have entered the sleep shift enabled state.
Therefore, even when there is an ECU 20 that cannot shift to the sleep mode due to a vehicle condition or a failure, the ECU 20 is forced to shift to a sleep shiftable state, and all the ECUs 20 (20A to 20D) in the network are moved. As the sleep mode, it is possible to reduce battery consumption and prevent the battery from running out. Further, since the engine stop can be detected without providing the ignition switch on / off detecting means, the wiring can be simplified.

FIG. 4 shows a second embodiment of the present invention.
One of the ECUs 20 connected to the multiplex communication line 30 is a battery monitoring ECU, and the receiving unit 23 receives a battery voltage signal. The storage unit 27 stores a reference value for the battery voltage.
In the flowchart of FIG. 4, when the other ECU 20 transmits the sleep shift enable signal SA, but its own ECU 20 is in a state where it cannot shift to the sleep mode, the battery voltage signal is received in S90 and the battery voltage is the reference. Judge whether or not it is greater than or equal to the value.
If the battery voltage is equal to or lower than the reference value, the process proceeds to step S70, and the ECU 20 is forced to shift to the sleep mode before the set time elapses. If the battery voltage is equal to or higher than the reference value, the process proceeds to step S30, and the ECU 20 is forced to shift to the sleep mode after the set time has elapsed.

  According to the above configuration, when the battery voltage signal from the battery monitoring unit is equal to or lower than the reference value, the ECU 20 is forced to enter the sleep mode without waiting for the set time to elapse after detecting the stop of the engine. Therefore, power supply to all the ECUs 20 is not continued until the set time elapses, so that battery consumption can be reduced and the battery can be prevented from running out.

  In addition, this invention is not limited to the said embodiment, The various form within the claim of this invention is included.

It is a block diagram of the multiplex communication system which is 1st Embodiment of this invention. It is a block diagram of a control unit. It is a flowchart which shows operation | movement of a control unit. It is a flowchart which shows 2nd Embodiment.

Explanation of symbols

10 Multiplex Communication System 20 (20A-20D) ECU (Control Unit)
22 transition determination unit 23 reception unit 24 transmission unit 25 processing unit 30 multiplex communication line SA sleep transition enable signal SB sleep shift disable signal

Claims (3)

A control unit connected to a plurality of other control units via a multiplex communication line,
A transition determination unit that determines whether or not transition from the high power consumption state operation mode to the low power consumption state sleep mode is possible, and outputs either a sleep transition enable signal or a sleep transition disable signal;
A transmission unit that periodically transmits either of the sleep transition enable signal and the sleep transition disable signal from the transition determination unit to the other control units;
A receiver for receiving either periodically in the sleep transition enable signal and the sleep transition disable signal from all other of the plurality of control units connected through the multiplex communication line,
While it is determined that the shifting-to-sleep mode disabling by the archive determining section receives the entire Heck et the sleep transition enable signal of the other of the plurality of control units, a processing unit for forcibly shift to the sleep mode after the setting time has elapsed ,
A control unit comprising: The receiving unit receives a battery voltage signal from battery monitoring means connected to the multiplex communication line,
The control unit according to claim 1, wherein the processing unit is configured to forcibly shift to the sleep mode before the set time elapses when the battery voltage is equal to or less than a reference value stored in the storage unit in advance.   A multiplex communication system characterized in that all of a plurality of control units connected via a multiplex communication line are the control units according to claim 1 or 2.

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