JP2000194403A - Load diagnosing device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load diagnosing device for vehicles capable of performing an fault diagnosis after the fault in addition to a stationary time load diagnosis, wherein a wire harness state after the fault can be diagnosed without driving a load. SOLUTION: A CPU 1 discriminates between an indispensable load and a disconnectable load for vehicle operation when a fault takes place, and when it discriminates the load as disconnectable, it turns off a switching element FET with a driving circuit 2 and disconnect the whole loads. Further, a minute current is fed to the disconnected loads through a current control element Tr turned on by the driving circuit 2 and through a resistance R2. A current detection circuit 3 and the CPU 1 decides whether the disconnection states of the corresponding loads are to be continued or released on the basis of the current- carrying state of the fed minute current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load diagnosis device for a vehicle, which is capable of performing a failure diagnosis after an accident in addition to a steady-state load diagnosis.

[0002]

2. Description of the Related Art In recent years, a control device for performing on / off control of electric components of an automobile has a function of not only controlling the operation of a load but also protecting the load from an overcurrent. There is an inrush current that flows and an abnormal current that flows due to a load failure or the like in a steady state thereafter. Therefore, it is desired that the control device not only protects against an abnormal current flowing due to a load failure or the like in a steady state, but also controls a load current of a lamp, a motor, or the like even when an inrush current occurs. A control device that responds to such a request, for example,
This is proposed in Japanese Patent Application Laid-Open No. Hei 1-301432.

In other words, a certain period after the load current is detected is defined as an inrush current detection period, and a period after the predetermined period is defined as a normal overcurrent detection period. However, load switching and failure detection operation can be performed without malfunction.

[0004]

However, a wire harness may be disconnected or short-circuited due to an accident or the like, and if the wire harness comes in contact with leaked oil or the like, there is a possibility that the current may be ignited by a current of about 1A. Then, in the conventional method of detecting the current while driving the load and taking measures such as breaking the circuit when the current value is abnormal, the inrush current is detected after the occurrence of the accident. Is assumed.

The present invention has been made in view of the above circumstances, and has as its object to provide a vehicle load diagnosis device capable of diagnosing the state of a wire harness after an accident without driving a load.

[0006]

To achieve the above object, according to the present invention, in a first aspect, a load-disabled load discriminating means for discriminating between a load in which the operation of a vehicle is indispensable at the time of an accident and a load which can be cut-off. In the event of an accident, load interrupting means for interrupting all of the interruptable loads, current supply means for supplying a minute current to the interrupted load, and a current supply state based on the supplied minute current. A determination unit configured to determine whether to continue or cancel the load cutoff state.

According to a second aspect of the present invention, in the vehicle load diagnostic apparatus according to the first aspect, the cut-off load determining means determines a load in which the operation of the vehicle is indispensable when an accident occurs and a load that can be cut off. Wherein the load interrupting means comprises switching means interposed between a power supply and a load, and a drive circuit for driving the switching means to cut off power supply when an accident occurs, and The means includes a current control element that is interposed between the power supply and the load, is driven by the drive circuit when an accident occurs, and supplies a small current to the load, and a resistor.

According to the first aspect of the present invention, when an accident occurs, the load is cut off and a minute current is supplied to the wire harness.
Investigate the presence / absence of disconnection / short circuit of the wire harness, and if the wire harness is disconnected / short circuited, determine whether to continue the cut-off state of the load.If not, determine whether to cancel the cut-off state of the load. Do. Thus, it is possible to prevent a fire from occurring by accidentally driving the load after the accident, and to safely operate only the normal load.

According to the second aspect of the present invention, it is possible to prevent the occurrence of a fire by accidentally driving a load after an accident and to safely operate only a normal load with a simple device configuration. it can.

[0010]

FIG. 1 shows an example of the configuration of a vehicle load diagnosis apparatus according to an embodiment of the present invention. In FIG. 1, a drive circuit 2 and a current / voltage detection circuit 3 are connected to a computer (CPU) 1. The computer (C
Although not shown, various sensors and various control devices (ECUs) in the vehicle are connected to the PU) 1, from which detection signals, failure signals, airbag operation signals, and the like are input, and the signals are sent to an alarm display device. It outputs a diagnostic signal. Also, the computer (CPU) 1 has a table showing a load that can be cut off and a load that cannot be cut off as shown in FIG. 3 and a table showing the inspection order performed at the time of detecting a broken line as shown in FIG. Is stored.

The drive circuit 2 has one output connected to the gate of the switching element FET and the other output connected to the base of the current control element Tr. Switching element FE
T has a drain connected to the power supply E via the resistor R1 and a source connected to the load 5 via the wire harness 4. Although the load 5 is a motor in the illustrated example, the switching element FET is provided for all loads.
Provided for each load.

The current control element Tr has a collector connected to the drain of the switching element FET and an emitter connected to the source of the switching element FET via the resistor R2. The current / voltage detection circuit 3 has a voltage detection terminal connected to both ends of the resistor R1, and a current detection terminal connected to a connection terminal between the resistor R2 and the source of the switching element FET. This current control element Tr is provided for each switching element FET.

Here, the computer (CPU) 1 corresponds to the load-breakable load determining means, and the computer (CPU) 1, the drive circuit 2, and the entire switching element FET correspond to the load-breaking means. And the current supply means
The computer (CPU) 1, the drive circuit 2, and the entire current control element Tr correspond to each other.
U) 1 corresponds to the current / voltage detection circuit 3.

Next, the operation of this embodiment will be described with reference to the block diagram of FIG. 1 and the flowchart of FIG.

In the flowchart of FIG. 2, the computer (CPU) 1 always performs a normal load diagnosis (step ST1) when the vehicle is running. In parallel with this, the computer (CPU) 1 performs a diagnosis process when an accident occurs (step ST1). ST2 to step ST8). The normal load diagnosis includes, for example, sensor failure diagnosis based on output signals of various sensors, actuator failure diagnosis based on the output state of an actuator circuit, and the like.

In the diagnosis process when an accident occurs, the computer (CPU) 1 first checks whether or not an accident has occurred (step ST2). This is performed by determining the presence or absence of an external interrupt signal such as a failure signal or an airbag activation signal. When a failure signal, an airbag activation signal, or the like is input from the outside, the computer (CPU) 1 determines a load required for operation in consideration of the running state (step ST).
3) The switching element FET for the load corresponding to the drive circuit 2 is turned off so as to shut off all other loads (step ST4). The load required for operation corresponds to the headlamp, for example, when traveling with the headlamp turned on. That is, the headlamp remains lit.

FIG. 3 is a table configuration showing an example of a load that can be cut off and a load that cannot be cut off created in the computer (CPU) 1. The horn or
There are audio systems, washers, wipers, fuel openers, non-hazard lamps, headlamp level actuators, etc. On the other hand, those that cannot be shut off include power windows, power seats and solenoids for door locks (all for escape), telephones (for emergency contact),
Turn lamps (for hazard display), meters (for warning), and the like. In FIG. 3, for example, regarding a hazard lamp, if the hazard lamp is disconnected or short-circuited, another lamp can be used instead. FIG. 3 is a mere example, and the setting of cut-off / non-cut-off, the priority of energization, and the like differ depending on the type of vehicle and other circumstances.

Next, the computer (CPU) 1 causes the drive circuit 2 to drive the current control element Tr to supply a small current to the wire harness 4 to the corresponding load, bypassing the switching element FET (step ST5). Monitor the output state of the current / voltage detection circuit 3 (step ST
6). The supply and monitoring of the minute current are performed individually for each of the interrupted loads. Since the load to be interrupted may vary depending on the nature of the accident, it may be difficult to determine the order of supply and monitoring in advance, but for example, it may be possible to assign an order to the control system. Can be

When a current does not flow through the resistor R2, the current / voltage detection circuit 3 outputs the fact to the computer (CPU) 1 together with the identification number of the load. Thereby, the computer (CPU) 1 can determine that the wire harness to the corresponding load is disconnected, and determine that the load is to be continuously set to the cutoff state (step ST).
7).

The current / voltage detection circuit 3 includes a resistor R1
Is output to the computer (CPU) 1 together with the identification number of the load if the voltage between both ends is equal to or less than the predetermined value. In this case, the computer (CPU) 1 determines that the wire harness to the corresponding load is short-circuited and the leak current is flowing, and similarly determines that the load is to be continuously set to the cutoff state (step ST7). ).

FIG. 4 is a table showing an example of the inspection order performed when disconnection is detected. This example shows the front ECU
3 illustrates lamp disconnection performed on one side. For example, the first is FR TURN (disconnection of the front right turn signal lamp), the second is CRA LP (disconnection of the clearance lamp), and the third is CNR LP (disconnection of the cornering lamp). ) Fourth, H-LP Lo (disconnection of headlamp (low beam)), Fifth, H-LP
Inspection is performed in order of Lo (head lamp (high beam) inspection), and finally (sixth) FR FOG LP (front right fog lamp inspection) in descending order of importance. This order is stored in the computer 1 in advance as a table.

A computer (CPU) 1 includes a driving circuit 2
At the same time, the switching element FET corresponding to the load that has been determined to maintain the cutoff is set to the off state,
The load which has decided to maintain the cutoff is notified to the external alarm display device by its identification number. As a result, appropriate warning processing can be performed, and careless load driving after an accident can be prevented.

On the other hand, the current / voltage detection circuit 3 includes a resistor R2
When the current is flowing through the resistor R1 and the voltage across the resistor R1 is a predetermined value, the fact is output to the computer (CPU) 1 together with the load identification number. In this case, the computer (CPU) 1 determines that the wire harness to the load is sound, determines that the load is released from the interrupted state (step ST8), and instructs the drive circuit 2 to apply the load to the load. The corresponding switching element FET is set to the ON state, and the load released from the interrupted state is reported to the external alarm display device by its identification number. As a result, only a normal load is driven after the accident.

As described above, according to this embodiment, when an accident occurs, the presence / absence of disconnection or short circuit of the wire harness can be checked by flowing a small current without operating the load. It is possible to prevent a fire from occurring by inadvertently driving the load later, and it is possible to safely operate only a normal load.

In addition, it is possible to check whether the wire harness is broken or short-circuited by a simple device configuration, and it is possible to prevent accidental driving of the load after an accident to prevent a fire from occurring. It can be operated safely.

In this embodiment, a switching element F is used as a load shedding means (switching means).
Although the ET is used, the switching may be performed using a relay or the like.

[0027]

As described above, according to the present invention, according to the present invention, in the event of an accident, the presence or absence of disconnection or short circuit of the wire harness is checked by applying a small current without operating the load. Can prevent accidental driving of the load after an accident and fire.
Only normal loads can be safely operated.

According to the second aspect, the presence or absence of disconnection or short circuit of the wire harness can be checked with a simple device configuration, and it is possible to prevent the occurrence of fire by accidentally driving a load after an accident. Only normal loads can be safely operated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a vehicle load diagnosis device according to the present invention.

FIG. 2 is a flowchart illustrating the operation of the embodiment shown in FIG.

FIG. 3 is a table configuration diagram showing an example of a load that can be cut off and a load that cannot be cut off.

FIG. 4 is an explanatory diagram showing an example of an inspection order performed when disconnection is detected.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Computer (CPU) 2 Drive circuit 3 Current-voltage detection circuit FET Switching element Tr Current control element R1, R2 Resistor

Claims (2)

[Claims] 1. An interruptable load determining means for determining a load indispensable for operation of a vehicle when an accident occurs and a load that can be interrupted, and a load interrupting means for interrupting all of the load that can be interrupted when an accident occurs. A current supply unit that supplies a minute current to the interrupted load; and a determination unit that determines whether to continue or cancel the interruption state of the load based on the energized state of the supplied minute current. A load diagnosis device for a vehicle. 2. The load diagnosis device for a vehicle according to claim 1, wherein the cut-off load determining means includes a table for discriminating a load in which the operation of the vehicle is indispensable at the time of occurrence of an accident and a load that can be cut off. The load interrupting means includes switching means interposed between a power supply and a load, and a drive circuit for driving the switching means to cut off power supply when an accident occurs, wherein the current supplying means comprises: A load diagnosis device for a vehicle, comprising: a current control element interposed between the power supply and a load, driven by the drive circuit at the time of occurrence of an accident to supply a small current to the load, and a resistor.