JPS62182801A - Abnormality detecting device for controller - Google Patents

Abstract

PURPOSE:To set an internal combustion engine system under a safe state even though a power supply line or an earth line of a detector has disconnection, by securing such a constitution where a trouble mode control signal generating means produces the signal to control a controlled system under a prescribed state when a trouble is detected by trouble detecting means and the controlled system is controlled under a safe state equal to the state where a signal line has disconnection. CONSTITUTION:When a power supply line of a target rotational frequency setting device 2 has disconnection, the earth potential is supplied to an A/D converter 12 through a resistance 16 as the 1st voltage level. In case an earth line has disconnection, the 3rd voltage level (high potential) approximately equal to the power supply voltage level is supplied to the converter 12 since the resistance value of the resistance 16 is higher enough than that of a variable resistance 21. When an output signal line has disconnection,the earth potential serving as the 1st voltage level is supplied to the converter 12 like a case where the power supply line has disconnection. Then a high potential if detected is not defined as the target rotational frequency and the target rotational frequency is set at the safe side like in case of the earth potential.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an abnormality detection device for a control device for an internal combustion engine.
In particular, the present invention relates to an abnormality detection device for a control device for safely operating an internal combustion engine.

[Conventional technology]

FIG. 4 is an overall configuration diagram showing an internal combustion engine system to which a conventional control device is applied. In FIG. 2, 101 is an internal combustion engine, which has an internal combustion engine main body 101a and a throttle valve 101b disposed in an intake passage. Reference numeral 102 denotes an ignition device for igniting the engine 101, and a rotation signal based on an opening/closing signal of the primary circuit of the ignition coil is input to the control device 1.

Reference numeral 2 denotes a target rotation speed setting device for arbitrarily and adjustable setting of a target engine rotation speed, and is composed of a variable resistor and the like, and generates a signal having a value corresponding to the set rotation speed. 103 is a pressure servo motor that drives the throttle valve 101b, and has a diaphragm 103b that changes according to the pressure in an operating pressure chamber 103a. Each passage communicates with a negative pressure source (intake negative pressure passage) and the atmosphere through the passage, and each passage is provided with orifices 106, 107, and the negative pressure side passage is provided with a surge tank 108 for compensating for pressure fluctuations. There is.

Reference numeral 3 denotes a position sensor for detecting the opening position of the throttle valve 101b, which is made of, for example, a variable resistor, and is integrated with the pressure servo motor 103 to detect the displacement position of the diaphragm 103b. has been entered. Further, the position sensor 3 includes an electric wire 3a and a resistor 3b connected to a power source or ground. The resistor 3b is a pull-up or pull-down resistor connected between the output signal line of the position sensor 3 and the electric wire 3a for fail-safe purposes. This resistor 3b is provided to operate the internal combustion engine system safely in the event of a signal wire breakage, and the resistance value of the resistor 3b is set to a value that is sufficiently larger than the resistance value of the variable resistor of the position sensor. There is.

The control device 1 is mainly composed of a microcomputer,
Furthermore, it is configured to include an A/D converter that digitally converts the analog voltage signal of the target rotation speed setting device 21 and the position sensor 3, and a transistor circuit that controls the power supply to each of the electromagnetic valves 104 and 105 on and off.

The atmosphere side solenoid valve 105 is a normally open solenoid valve that opens when the power supply is turned off, and the negative pressure side solenoid valve 104 is a normally closed solenoid valve. In drive mode, throttle close drive mode, and throttle hold mode, on and off combinations are driven as shown in the table.

Next, the operation of the control system of the internal combustion engine system will be explained. An output signal a of the position sensor 3 representing the opening position of the throttle valve 101b is input to the control device 1. In addition, the target rotation speed signal from the target rotation speed setting bag W2 is output from the sumo control device 1.
is input. The control device 1 compares the target throttle valve opening position corresponding to the target rotational speed signal with the throttle opening position of the throttle valve 101b detected by the position sensor 3, and determines whether the opening position of the throttle valve 101b is the target throttle opening position. The solenoid valves 104 and 105 are controlled to be at the valve opening position. Through this control, the opening position of the throttle valve 101b converges to the target throttle valve opening position.

[Problem that the invention seeks to solve]

However, in an internal combustion engine system having such a configuration and function, even if the internal combustion engine system can be set to a safe state when the output signal line of the position sensor 3 is disconnected, the electric wire 3a as the power line or ground line of the position sensor 3 is When the wire is disconnected, the internal combustion engine system may not be able to be set to a safe state with the resistor 3b serving as the pull-up resistor or pull-down resistor.

The present invention has been made in view of these points, and its purpose is to detect abnormalities in the control device that can set the internal combustion engine system to a safe state even if the power line or ground wire of the detection device is disconnected. The purpose is to obtain a detection device.

[Means for solving problems]

In order to achieve such an object, the present invention includes a detection device that detects information necessary for control, and a control signal that is connected to the detection device by at least one line to control a controlled object to a desired state. a control signal generating means for generating a control signal; a state determining means for setting the signal state at the time of an output signal line failure of the detection device to a first or second voltage level; and at least two voltage levels determined by the state determining means. 3rd different from
failure detection means for detecting the voltage level of the third voltage level; failure control signal generation means for controlling the controlled object to a predetermined state when the third voltage level is detected; and an output signal and control of the failure control signal generation means. The apparatus is provided with an output signal of the signal generating means and a driving means for controlling the controlled object in accordance with the output signal of the signal generating means.

[Operation] In the present invention, when an abnormality is detected, the failure detection means generates a signal to cause the failure control signal generation means to control the controlled object to a predetermined state, so that the same safe state as the state when the signal line is disconnected is generated. Control the controlled object.

〔Example〕

An embodiment of an abnormality detection device for a control device according to the present invention is shown in FIG. In FIG. 1, 4 is a detection device that has at least an output signal line and one or more power supply lines and detects information necessary for control, and 5 is connected to the detection device 4 by at least one line and detects the control target. control signal generating means for generating a control signal to be controlled to a desired state; 6, state determining means for setting the signal state at the first or second voltage level when the output signal line of the detection device 4 fails; 7; 8 is a fault detection means for detecting a third voltage level different from at least the two voltage levels determined by the state determining means 6; 8 is a fault detection means 7;
Failure control signal generating means controls the state of the controlled object to be the same as the state determined by the state determining means 6 at the time of a failure by the output signal of the failure control signal generating means 9; It is a driving means that controls a controlled object according to a signal.

FIG. 2 shows a more specific example of the apparatus shown in FIG. 1.

In FIG. 2, the same or equivalent parts as in FIG. 4 are given the same reference numerals. In the figure, the control device 1 includes a sensor power supply circuit 11, an A/D converter 12, a CPU 13, a drive circuit 14, resistors 15 to 18, and terminals Tll to T.
16. The resistors 16 and 18 constitute a state determining means, the CPU 13 constitutes a failure detection means, a control signal generation means, and a failure control signal generation means, and the drive circuit 14 constitutes a drive means. Also, the resistor 16 is a pull-down resistor,
Resistor 18 is a pull-up resistor. The target rotation speed setting device 2 and the position sensor 3 constitute the detection device 4 shown in FIG. It has terminals T31 to T33.

Next, the operation of the apparatus shown in FIG. 2 constructed as described above will be explained. When the power supply line of the target rotation speed setting device 2 is disconnected, a ground potential as a first voltage level is input to the A/D converter 12 through the resistor 16. Conversely, if the ground wire is disconnected, the resistance value of resistor 16 will change to variable resistor 2.
Since the value is sufficiently larger than the resistance value of No. 1, the third voltage level is approximately equal to the power supply voltage (hereinafter referred to as "high potential").
is input to the A/D converter 12. In the case of a disconnection of the output signal line, the ground potential as the first voltage level is input to the A/D converter 12 as in the case of a disconnection of the power supply line. If the potential output from the target rotation speed setting device 2 and input to the A/D converter 12 is ground potential, the target rotation speed itself is low and is on the safe side as an internal combustion engine system, but the A/D
When the input potential of the D converter 12 is a high potential, the target rotation speed itself is high, and the internal combustion engine system is not on the safe side. Therefore, when a high potential is detected, it is necessary not to directly use the high potential as the target rotation speed, but to set the target rotation speed on the safe side, as in the case of the ground potential. This is shown in the flowchart of FIG.

In FIG. 3, the current rotation speed (N) is detected in step 41 based on information from the position sensor 3, and then the target rotation speed (NO) is read from the target rotation speed setting device 2 in step 42. Next, in step 43, the target position (PO) of the throttle opening is adjusted between the current rotation speed (N) and the target rotation speed (N).
O), the current throttle position (P) is read in step 44, and the process moves to step 45.

In step 45, the state in which the target rotation speed (NO) is high, that is, the state in which the target rotation speed setting device 2 outputs the rotation speed (K1) corresponding to a high potential, is maintained for a certain period of time ia
If it continues for a certain period of time or more, the throttle valve 101b (see FIG. 4) is driven to the closing side in step 48. In other words, it is driven to the safe side. If it has not continued for a certain period of time, the process moves to step 46, which will be described later.

Next, the operation when the power line, ground line, or output signal line of the position sensor 3 is disconnected will be explained.

These operations are similar to those of the target rotation speed setting device 2. That is, if the power supply line is disconnected, the resistance value of the resistor 18 is sufficiently larger than the resistance value of the variable resistor 31, so the A/D converter 12 has a third voltage that is approximately equal to the ground potential.
voltage level (hereinafter referred to as "low potential") is input.

Conversely, if the ground line is disconnected, the power supply potential as the second voltage level is input to the A/D converter 12. In the case of a break in the output signal line, the second
The power supply potential as a voltage level is input to the A/D converter. If the potential output from the position sensor 3 and input to the A/D converter 12 is the power supply potential, it means that the current throttle opening position is close to the maximum open side, so the throttle valve 101b is driven to the closed side. This operation is a safe operation for an internal combustion engine system. A/
When the input potential of the D converter 12 is a low potential, it means that the throttle valve 101b is close to the maximum closed state, and the throttle valve 101b is further controlled to be driven to the open side. This operation is not a safe operation for an internal combustion engine system. Therefore, when a low potential is detected, it is necessary not to use the low potential as the current opening position, but to set the current opening position on the safe side, as in the case of the power supply potential. This is shown in the flowchart of FIG.

In FIG. 3, if the target rotational speed (No) is smaller than the rotational speed (K1) corresponding to the high potential in step 45, the process moves to the next step 46. In step 46, it is determined whether the current throttle position (P) is below the throttle position (K2) corresponding to a low potential for a certain period of time or more, and if it continues for a certain period of time or more, step On the fourth day, the throttle valve 101b (see FIG. 4) is driven to the closed side. In other words, it is driven to the safe side.

If it has not continued for a certain period of time or more, the process moves to the next step 47 and normal position control is performed. That is, the opening position (P) of the throttle valve 101b is controlled so as to converge to the target throttle valve opening position (PO), and thereby the rotation speed (N) of the internal combustion engine converges to the target rotation speed (NO). do.

By performing the above-described control, even if either the power line 5 ground line or the output signal line is disconnected, the operation of the internal combustion engine system can be made to be on the safe side.

〔Effect of the invention〕

As explained above, the present invention detects information necessary for control, generates a control signal based on this information, and changes the signal state at the time of a failure of the output signal line for outputting the information to the first or second
A third voltage level different from these voltage levels is detected, and the state of the controlled object is the same as the state of the controlled object established at the first or second voltage level by detecting the third voltage level. By controlling the control target using each of the level control signals described above, the throttle valve of the internal combustion engine system can be driven to the safe side, which has the effect of preventing abnormal operation of the internal combustion engine system due to failure.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing an embodiment of an abnormality detection device for a control device according to the present invention, FIG. 2 is a circuit diagram showing an embodiment of the device in FIG. 1, and FIG. 3 is a diagram similar to the one shown in FIG. , a flowchart for explaining the operation of the apparatus shown in FIG. 2, and FIG. 4 a system diagram showing the internal combustion engine system. l...Control device, 2...Target rotation speed setting device,
3...position sensor, 4...detection device, 5...
- Control signal generating means, 6... State determining means, 7...
...Failure detection means, 8.. Failure control signal generation means, 9.. Drive means, 10.. Controlled object, 11.
...Sensor power supply circuit, 12...A/D converter, 1
3...CPU, 14...Drive circuit, 15-18
...Resistance, 21.31...Variable resistance, Tll~
T16. T21-T23. T31 to T33...terminals.

Claims (1)

[Claims] A detection device that has at least an output signal line and one or more power supply lines and detects information necessary for control, and a control that is connected to this detection device by at least one line and that controls the controlled object to a desired state. A control signal generation means for generating a signal, and a first or second
a fault detection means for detecting a third voltage level that is different from at least the two voltage levels determined by the state determining means; and detecting the third voltage level. failure control signal generating means for controlling the controlled object to a predetermined state when the failure occurs; and a drive for controlling the controlled object according to the output signal of the failure control signal generating means and the output signal of the control signal generating means. An abnormality detection device for a control device, comprising: means.