JPH03262757A - Vehicle control device with power source abnormality avoiding function - Google Patents

Abstract

PURPOSE:To improve the reliability of operation by comparing detected results of a main voltage detecting means and a backup voltage detecting means, and setting the power line with the higher voltage as the control reference of an electronic control circuit when an abnormality of the power line is detected. CONSTITUTION:This device has a vehicle driving circuit C1 receiving the power feed from an on-vehicle battery DB and performing the necessary process to drive a vehicle and an electronic control circuit C2 receiving the power feed from a main power line ML via a main switch MS from the on-vehicle battery DB and a backup power line SL bypassing the main switch MS. An abnormality judging means C5 comparing the detected results of voltage detecting means C3, C4 detecting the voltage of the lines ML, SL and detecting an abnormality on either power line is provided. When an abnormality on either power line is detected, the power line with the higher voltage is set by a Voltage selecting means C6 as the control reference of the electronic control circuit C2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention (in which an electronic control circuit operates by receiving power from two systems, a main power line and a backup power line, and an abnormality in the main power line) The present invention relates to a vehicle control device with a power supply abnormality avoidance function that connects a power line passing through a vehicle drive circuit and a main power line in order to cope with the problem.

[Prior Art] A vehicle control device is a vehicle drive circuit that executes processes necessary for driving a vehicle (for example, a fuel injection valve that injects fuel into an internal combustion engine, and an idle speed control that adjusts the amount of intake air at idle). - It is composed of a valve (hereinafter referred to as 1SCV) and an electronic control circuit that controls the operating amount of these vehicle drive circuits, and both operate by receiving power from the vehicle battery.

Then, the electronic control circuit monitors the voltage of the vehicle battery and adjusts the operation amount of the vehicle drive circuit according to the voltage so that the operation amount of the vehicle drive circuit remains at the target value even if the voltage of the vehicle battery fluctuates. It has a function.

In this way, the voltage of the vehicle battery has a significant effect on the driving characteristics of the vehicle. Therefore, various techniques have been proposed to reliably and quickly detect/notify malfunctions or abnormalities in the vehicle battery voltage that exceed the adjustment ability of the electronic control circuit.

For example, in Japanese Patent Application Laid-Open No. 63-273038 (L), even if the voltage of the in-vehicle battery temporarily drops, if the oil generator that charges the in-vehicle battery is normal, an abnormality notification is not executed, and the accuracy of abnormality detection is reduced. Techniques for improving this are disclosed.

On the other hand, as a fail-safe technology, the following vehicle control device with a power abnormality avoidance function is known, which continues to maintain the functions of the vehicle control device even if the power supply line from the on-board battery is disconnected.

That is, since the electronic control circuit and the vehicle drive device are required to operate while the vehicle is operating, they are connected to the vehicle battery DB via the main power line ML via the main relay MR linked to the key switch KS, as shown in FIG. be done. In order to continue operating the vehicle even if an abnormality such as a wire breakage occurs at the position marked with an x next to the main power line M, the power line BL and the main power A power supply line that connects the line ML and passes through the vehicle drive circuit is configured in advance.

[Problems to be Solved by the Invention] As described above, as techniques for dealing with power supply voltage abnormalities of in-vehicle batteries, there are two types of technology: a technique for detecting/notifying the abnormality, and a fail-safe technique for avoiding the abnormality. However, since the purposes of these two technologies are different, the following new issues have arisen.

As described above, the electronic control circuit detects the power supply voltage of the vehicle-mounted battery and adjusts the amount of operation of the vehicle drive circuit according to the detected voltage. For example, a fuel injection valve, which is one of the vehicle drive circuits, has a characteristic that the amount of fuel injected per unit time generally decreases when the power supply voltage of the vehicle battery decreases.

Therefore, when the power supply voltage of the vehicle-mounted battery decreases, the electronic control circuit sets the invalid injection time longer and executes adjustment processing such that the target amount of fuel is injected from the fuel injection valve.

On the other hand, if a disconnection occurs in the main power line ML of the electronic control circuit, the fail-safe function allows, for example, +S
Continuous operation is ensured by receiving power from power line B via the CV. However, in reality, the power supply voltage applied to the electronic control circuit becomes lower than the power supply voltage of the vehicle battery DB due to the influence of other electrical loads such as passing through SCv. Therefore, the electronic control circuit recognizes this low voltage as the current power supply voltage of the vehicle battery DB and executes control of various vehicle drive circuits. To explain using the example above, the electronic control circuit (direct vehicle drive circuit) that recognizes that the power supply voltage of the vehicle battery DB is lower than the actual value (one fuel injection valve, which is one of the direct vehicle drive circuits) has a longer invalid injection time. As a result, the vehicle is operated with excess fuel.

Therefore, if an abnormality such as a disconnection occurs in the mutual power line ML and the fail-safe function is activated, no detection/notification will be performed as an abnormality in the power supply voltage, and furthermore, the electronic control circuit will perform incorrect control. It continues to do so.

The present invention has been made to solve the above-mentioned problems, and it is possible to reliably detect abnormalities such as disconnection of the power line, and even in such cases, it is possible to properly detect abnormalities such as disconnection of the power line, and even in such cases, the vehicle The object of the present invention is to provide a vehicle drive unit with an excellent power supply abnormality avoidance function and a fail-safe function for controlling the drive circuit.

[Means for Solving the Problems] As shown in the basic configuration diagram in FIG. The vehicle drive circuit C1 that executes the process receives power from two systems: the main power line ML from the on-board battery DB via the main switch MS, and the backup power line SL bypassing the main switch MS to drive the vehicle. and an electronic control circuit C2 that controls the circuit C1, and in order to cope with an abnormality in the main power line ML, a power supply abnormality avoidance circuit that connects the power line BL passing through the vehicle drive circuit C1 and the main power line ML. The functional vehicle control device includes: main voltage detection means C3 for detecting the voltage of the main power line ML; backup voltage detection means C4 for detecting the voltage of the backup power line SL; a power line abnormality determination means C5 that compares the detection results with the voltage detection means C3 and detects an abnormality in any power line; and when an abnormality is detected in any power line by the power line abnormality determination means C5; The gist of the present invention is a vehicle control device with a power supply abnormality avoidance function, characterized in that it is equipped with a voltage selection means C6 that sets the higher voltage of the power line as a control reference for the electronic control circuit C2.

[Operation] The electronic control circuit C2 in the vehicle control device of the present invention receives power from two systems: the main power line M via the main switch MS and the backup power line SL bypassing the main power line M from the in-vehicle battery DB. Controls the vehicle drive circuit C1.

For example, when there is various learning information that is required to be retained even when the main switch MS is opened as internal information of the electronic control circuit C2, the main switch MS
Power must be continuously supplied to the internal storage element regardless of the state of the internal storage element.

In such cases, conventional backup electric power line SL
There are two power supply lines in addition to u.

Further, for fail-safety, the power line BL passing through the vehicle drive circuit C1 is connected to the main power line M.

Furthermore, the vehicle control device with power supply abnormality avoidance function of the present invention is equipped with various means for the following functions.

Main voltage detection means C3 and backup voltage detection means C4
is the main power line ML and the backup power line SL
Detects the voltage of Note that in a normal state, the potential difference between these two power lines is equal to the voltage drop caused by the main switch MS, and is approximately "O".

Therefore, the power line abnormality determining means C5 compares the detection results of the main voltage detecting means C3 and the backup voltage detecting means C4, and detects an abnormality in any of the power lines. That is, under normal conditions, there is no potential difference between the two power lines, but when an abnormality occurs in the main power line ML and the failsafe function is activated, or when an abnormality occurs in the backup power line SL. , a corresponding potential difference occurs between the two types of lines. By detecting this,
Determine abnormalities in power lines.

Note that the reference value of the potential difference when determining an abnormality varies depending on the size of the electrical load connected to each power line, etc. Therefore, it is appropriately set based on the magnitude of the load on the vehicle drive circuit C], the electronic control circuit C2, and its peripheral circuits.

Further, the voltage selection means C6 operates when the power line abnormality determination means C5 determines that the power line is abnormal;
The one with higher voltage of the two power lines is connected to electronic control circuit C.
This is set as the second control standard.

As mentioned above, some vehicle drive circuits C] have a characteristic that the amount of operation depends on the power supply voltage, and in order to optimally control this type of vehicle drive circuit c1, the electronic control circuit C2 is controlled by the power supply voltage. It has a function to adjust the amount of operation according to. When a difference occurs between the power supply voltages of the two power supply lines to the electronic control circuit C2, it is difficult to determine which power supply voltage should be used to adjust the amount of operation to the vehicle drive circuit C1. Become. Therefore, by the action of the voltage selection means C6, the higher potential of the power lines is set as the reference for control.

EXAMPLES Hereinafter, in order to explain the present invention more specifically, the present invention will be described in detail with reference to Examples.

[Embodiment] FIG. 2 shows an electric circuit block diagram of a vehicle control device with a power abnormality avoidance function, which is an embodiment of the present invention.

As shown in the figure, the voltage source of the vehicle control device is a general in-vehicle battery], and the ignition coil 2 is used as the vehicle drive circuit.
0. Three fuel injection valves 30a, 30b, 30C
and I5CV40.

Further, an electronic control circuit 50 that controls these vehicle drive circuits 20 to 40 according to the driving state of the vehicle controls intake pipe negative pressure PM.
, cooling water temperature (W), intake air temperature (TH), etc. are inputted via the A/D converter 50a, and the information is input to the microcomputer.
By processing a control program prestored in the built-in ROM of the unit 50b (hereinafter referred to as MC [J50b), the amount of operation of each vehicle drive circuit 20 to 40 is determined, and a signal corresponding to the determination is sent at a predetermined timing. Output. For example, the base signal to the ignition coil driving transistor 50c, which is one type of output signal, becomes a low potential when the optimum ignition timing calculated by the control program is reached.
A high voltage is induced on the secondary side of the ignition coil 20. Further, the base voltages applied to the transistors 50d and 50e for driving the fuel injection valve 30 and the 15CV 40 are applied only for a period determined by the control program, and the amount of fuel injection and the amount of intake air during idling are adjusted. Note that the Zener diode 50f, capacitor 50g, resistor 50h, diode 50j, etc. attached to these driving transistors 50d and 50e are connected to the driving transistor 50 from an impulsive voltage.
d, 50e.

Therefore, basically, power supply to the vehicle drive circuits 20 to 40 and the electronic control circuit 50 only needs to be performed while the vehicle is operating. Therefore, power is supplied to the vehicle drive circuits 20 to 40 via a main relay 60 that is closed by operating an ignition switch (not shown). Then, power is supplied to the electronic control circuit 50 via the main relay 60 to the terminal 50i.

Further, inside the electronic control circuit 50, the collector of the SCv driving transistor 50e and the power line from the main relay 60 are connected via a diode 50j. This is the main relay 60i & terminal 50
A fail-safe function is ensured against an abnormality such as a disconnection that occurs in the power line leading to the power line (for example, point A in the figure).

On the other hand, in order to further improve the control accuracy of each of the vehicle drive circuits 20 to 40, the MCU 30b in this embodiment controls each of the drive transistors 50c to 50 based on the past driving state.
A so-called learning control is adopted in which a correction amount for optimally correcting the output signal to 0e is learned and updated. Therefore, in order to continue to retain the various correction amounts learned up to this point even after the main relay 60 is released, backup power is supplied directly from the on-board battery to the terminal 50k, and the stored contents of the built-in RAM are hold.

Furthermore, the electronic control circuit 50 of the vehicle control device of this embodiment is
The voltage of the main power supplied from the terminal 50i and the voltage of the main power supplied from the terminal 50k
In order to monitor the voltage VBB of the backup power supplied from the
It is connected to the A/D converter 50a through the A/D converter 50a. This allows Mcusob to input the voltage of each power line as digital information without being influenced by voltage fluctuations and noise that occur when driving the vehicle drive circuits 20 to 40.

Built-in ROM of the electronic control circuit 50 configured as described above
A power supply voltage monitoring program as shown in the flowchart of FIG. 3 is stored in advance, and is repeatedly executed at predetermined time intervals by the MCU 30b from the time when the main relay 6o is closed.

Hereinafter, processing based on the power supply voltage monitoring program will be explained in detail along the flowchart of FIG.

When the processing of the power supply voltage monitoring program starts, terminal 5
The value of the voltage VB of 0i is read from the A/D converter 50a (step 100), and the value is set as the control reference voltage Vbas
(step 11o).

Two, the control reference voltage bas (is voltage data used when determining the invalid injection time etc. of the companion fuel injection valve 30, in other words, is the estimated value of the power supply voltage of the vehicle drive circuits 20 to 40). As shown in FIG. 2, both the terminal 50i and each vehicle drive circuit 20 to 401 receive power from the vehicle battery 10 via the main relay 60. Therefore, in principle, the monitor voltage of this terminal 50i is the vehicle drive circuit. This is because it can be estimated to be equal to the power supply voltage of the circuits 20 to 40.

Next, the voltage VBB of the backup power supplied from the terminal 50k is similarly read from the A/D converter 50a (step 20), and the difference between the two voltage values thus obtained (
It is determined whether or not VBB-VB) is greater than or equal to a predetermined value of 181 (step) 30.

The determination in step 130 has the following physical significance. That is, when normal power is being supplied from the onboard battery 10 to the terminal 501 and the terminal 50k, the voltage values VB, V8B The difference is main relay 60
Since it is the voltage drop of , it is almost "○".

However, an abnormality such as a disconnection occurs at point A in Figure 2, and the fail-safe function is activated, causing the l
When the power from 5CV40 is supplied to the terminal 50, a potential drop corresponding to the voltage drop at 15cV40 occurs.

Therefore, the predetermined value FBI used for the determination in step 130
Therefore, the difference between voltage VBB and voltage VB that appears when such a fail-safe function is activated is determined theoretically or experimentally from the characteristics of 1sCV40, and an abnormality in the power line to terminal 50i is determined.

Therefore, when a positive determination is made in step 130, it is determined that the fail-safe function is activated, and the control reference voltage Vbas is set to the voltage VBB (step 140). It is determined whether or not it continues (step 150), and only if it continues, an abnormality in the main power line leading to the terminal 50 is notified and the processing of this program ends. Note that the reason why the abnormality notification is made conditional on the elapse of a predetermined time is to prevent abnormality notification from being executed due to temporal noise or the like.

On the other hand, when the determination process in step 130 yields a negative result, the voltage difference (VB-VBB) is equal to the predetermined value FB2.
It is determined whether or not this is the case (step) 70. That is, when an abnormality occurs in the backup power line to the terminal 50k, the voltage drop FB2 that may occur in the voltage VBB due to an abnormality such as an increase in contact resistance or a disconnection is determined theoretically or experimentally in advance, and the predetermined voltage drop FB2 is determined in advance. value FB2
The difference of the backup power line is determined based on whether or not the above difference occurs.

When a negative determination is made in step 170, since both the power lines for the terminals 50i and 50k are normal, the correction values for learning control backed up in the built-in RAM of the MCLI 50b are also considered normal, and the learning control is canceled. Reset flag F for commanding (step 18
0) and exit this program.

On the other hand, if a positive determination is made in step 170, it is determined whether or not such a situation has continued for a predetermined period of time (step 19o); if the situation is temporary, the process proceeds to step 180. and transition. However, if such a state continues for more than a predetermined time, the reliability of the correction values used for learning control will decrease, so the flag that commands the cancellation of learning control will be set to "1". At the same time, the program is set (step 20o), and a report indicating that an abnormality has occurred in the power line to the terminal 50 is executed (step 210), and the program is terminated.

According to the vehicle control device with a power supply abnormality avoidance function of this embodiment configured as described above, the following effects are obvious.

Even if an abnormality occurs in the main power line to terminal 50i and the failsafe function is activated, it is possible to accurately detect the abnormality in the main power line by calculating the potential difference (VBB - VB) that occurs at that time. can.

In this case, the voltage value VBB that accurately reflects the terminal voltage of the vehicle battery 10 is set as the control reference voltage V b
In order to set it as AS, for example, it is possible to prevent adverse effects such as excessive fuel being injected from the fuel injection valve 30 in advance, and
Can be quickly avoided.

In addition, it is possible to detect abnormalities in the voltage value VBB of the backup power line by simple calculations, and in the event of an abnormality, learning control using correction values with reduced reliability is immediately canceled. . Therefore, erroneous learning control is not executed, and the driving characteristics of the vehicle can be maximized.

Furthermore, since the lapse of a predetermined period of time is a prerequisite for reporting an abnormality in the power supply line, the occurrence of false alarms due to temporal noise, etc. can be completely avoided.

[Effects of the Invention] As explained above, the vehicle control device with power supply abnormality avoidance function of the present invention compares the detection results of the main voltage detection means and the backup voltage detection means using the power line abnormality determination means, and detects abnormalities in the power line. To detect. If an abnormality is detected, the voltage selection means sets the higher voltage power line as the control reference for the electronic control circuit.

Therefore, it is possible to reliably detect abnormalities in the power line, including activation of the fail-safe function.

Further, even when an abnormality occurs, there is an excellent effect that the vehicle drive circuit can be appropriately controlled in accordance with the actual power supply voltage of the vehicle-mounted battery.

[Brief explanation of drawings]

Fig. 1 is a basic configuration diagram of the present invention, Fig. 2 is an electric circuit block diagram of a vehicle control device which is an embodiment of the present invention, Fig. 3 is a flowchart of a power supply voltage monitoring program, and Fig. 4 is a conventional 3A and 3B each illustrate a configuration explanatory diagram of a vehicle control device. ]O... Vehicle battery 20... Ignition coil 30
a, 30b, 30c...Fuel injection valve 40...l S
CV 50...Electronic control circuit 50a-A/D
Converter 50b, -MCU60...Main relay Fig. 1

Claims (1)

[Claims] 1. A vehicle drive circuit that receives power from the on-board battery and executes processes necessary for driving the vehicle, and a main power line from the on-board battery via a main switch, and a backup power line that bypasses the main switch. an electronic control circuit that receives power supply and controls the vehicle drive circuit, and connects a power line passing through the vehicle drive circuit with the main power line in order to cope with an abnormality in the main power line; In a vehicle control device with an abnormality avoidance function, main voltage detection means for detecting the voltage of the main power line, backup voltage detection means for detecting the voltage of the backup power line, the backup voltage detection means and the main voltage detection means power line abnormality determination means for detecting an abnormality in any of the power lines by comparing the detection results with the
It is characterized by comprising voltage selection means for setting the higher voltage of the power line as a control reference for the electronic control circuit when an abnormality is detected in any of the power lines by the power line abnormality determination means. Vehicle control device with power abnormality avoidance function