JP3663269B2 - Abnormality detection apparatus and method for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus and method for detecting an abnormality in an internal combustion engine, and more particularly to an apparatus and method for detecting an abnormality in a throttle control device.
[0002]
[Prior art]
In recent years, an internal combustion engine mounted on a vehicle is controlled by an electronic control system using a computer. For example, the throttle valve of an internal combustion engine is controlled as follows (electronic throttle control). The amount of depression of the accelerator pedal is converted into an electric signal and input to the computer. The computer calculates the input depression amount together with operating conditions such as the rotational speed and water temperature of the internal combustion engine and the output values of various sensors, and determines the optimum throttle valve opening (target opening) from the calculation results. The opening / closing of the throttle valve is adjusted by the computer controlling an actuator (such as a motor or an electromagnetic clutch that transmits the driving force of the motor to the throttle valve) based on the target opening.
[0003]
When adjusting a throttle valve by such an electronic control system, if an abnormality occurs in an actuator system that drives the throttle valve, the throttle valve cannot be operated normally. As a control device for appropriately running the vehicle even when the internal combustion engine is abnormal, for example, Japanese Patent Laid-Open No. 5-71365 discloses a rotation speed adjustment device for an internal combustion engine. In this rotational speed adjusting device, a clutch is connected during normal operation, and the throttle valve is electronically controlled by the driving force of the motor. When an abnormality occurs, the clutch is disengaged and the driving force of the motor is not transmitted, and the throttle valve is mechanically controlled according to the amount of operation of the accelerator pedal by the driver.
[0004]
[Problems to be solved by the invention]
It is preferable to detect an abnormality of the internal combustion engine, for example, an abnormality of an electromagnetic clutch of an actuator system or an abnormality of a relay for supplying power from a driving power source to the motor before starting the engine. However, it is necessary to detect the abnormality of the internal combustion engine in the abnormality detection mode instead of the normal control mode. Accordingly, there is a predetermined time delay from when the driver turns on the ignition (IG) switch until the engine is actually started, which impedes instantaneous engine start.
[0005]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an abnormality detection device and method for an internal combustion engine that reduces the chance of a time delay that hinders instantaneous engine start. is there.
[0006]
[Means for Solving the Problems]
An abnormality detection apparatus for an internal combustion engine according to the present invention stores a first abnormality detection means for detecting an abnormality of the internal combustion engine when the engine is stopped, and a result when the first abnormality detection means detects an abnormality. Storage means, and second abnormality detection means for detecting abnormality of the internal combustion engine at the next engine start only when the result of detecting abnormality is stored in the storage means, This achieves the above object.
[0007]
In one embodiment, the internal combustion engine includes a throttle control device that drives a throttle valve, and the throttle control device drives the throttle valve using an electric actuator, and the first and second abnormality detections are performed. Each of the means detects an abnormality of a relay that supplies power from the power source to the electric actuator.
[0008]
The first and second abnormality detecting means may determine that the relay is abnormal when energization of the electric actuator is continued for a predetermined time after the relay is in a non-operating state.
[0009]
In one embodiment, the internal combustion engine includes a throttle control device that drives a throttle valve, and the throttle control device includes a motor and an electromagnetic clutch that transmits a driving force of the motor to the throttle valve. Each of the first and second abnormality detecting means detects an abnormality of the electromagnetic clutch.
[0010]
When the throttle valve is driven when the motor is driven with the electromagnetic clutch disconnected and the electromagnetic clutch opened, the first and second abnormality detection means It may be judged abnormal.
[0011]
An abnormality detection method for an internal combustion engine according to the present invention includes: a first abnormality detection step for detecting an abnormality of the internal combustion engine when the engine is stopped; a step of storing a result of the first abnormality detection step; The step of determining the stored result at the time of starting, and detecting the abnormality of the internal combustion engine at the time of starting the engine only when it is determined that the result of detecting the abnormality in the determining step is stored . 2 anomaly detection steps, whereby the above object is achieved.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The abnormality detection device for an internal combustion engine according to the present invention can be configured in combination with or included in a control device for an internal combustion engine. The abnormality detection device for an internal combustion engine according to the present invention detects temporary abnormality by the first abnormality detection means for detecting abnormality of the internal combustion engine when the engine is stopped, and when the first abnormality detection means detects abnormality, Store the result in memory. When it is stored in the memory that an abnormality has been detected by the temporary abnormality detection, the abnormality of the internal combustion engine is detected by the second abnormality detection means at the next engine start (this abnormality detection). That is, when abnormality is detected by temporary abnormality detection when the engine is stopped, this abnormality detection is performed when the engine is started. Therefore, since this abnormality detection at the time of engine start is performed only when there is a high possibility that there is an abnormality in the internal combustion engine, the engine start delay caused by the execution of abnormality detection is compared to the case where abnormality detection is always performed at the time of engine start. Can be greatly reduced.
[0013]
Hereinafter, a case where the present invention is applied to a throttle control device that drives a throttle valve will be described as a more specific embodiment of the present invention with reference to the drawings.
[0014]
FIG. 1 schematically shows a throttle control apparatus 100 to which one embodiment of the present invention is applied. 1 and FIG. 2 to be described later show only the part of the actuator system controlled by the computer (ECU) in the throttle control device 100, and the accelerator operation system is not shown.
[0015]
As shown in FIG. 1, in the throttle control device 100, the throttle valve 14 is driven using the electric actuator 10. The electric actuator 10 includes a DC motor 11 and an electromagnetic clutch 12 that transmits a driving force of the DC motor to the throttle valve 14. The driving force transmitted by the electromagnetic clutch 12 is transmitted to the throttle valve via the reduction gear 13. The throttle valve 15 is provided with a throttle sensor 15 that detects the opening of the throttle valve.
[0016]
FIG. 2 schematically shows a control system of the electric actuator 10. As shown in FIG. 2, the electric power of the drive power supply 21 is supplied to the DC motor 11 and the electromagnetic clutch 12 via the relay 22. Relay 22, distribution of electric power supplied from relay 22, DC motor 11, and electromagnetic clutch 12 are all controlled by computer (ECU) 20. In the present embodiment, as shown in FIG. 2, an electromagnetic relay having a switch 23 and a coil 24 is used as the relay 22. The relay 22 is not limited to this, and may be a semiconductor relay as long as it is an element that controls on / off of power supply from a drive power source.
[0017]
(Embodiment 1)
Next, the operation of the abnormality detection device of the present invention and the abnormality detection method will be described for the case of detecting abnormality of the relay 22 in the system as described above. Examples of the abnormality of the relay 22 include welding of the switch 23, abnormality of the spring, disconnection or short circuit of the coil 24, and the like. In the present specification, the relay abnormality including these various abnormalities is referred to as “relay welding”.
[0018]
FIG. 3 is a flowchart showing this abnormality detection executed when the IG switch is turned on to detect welding of the relay 22 as an example of abnormality detection. Similarly, FIG. 4 is a flowchart showing temporary abnormality detection that is performed when the IG switch is turned off for detecting welding of the relay 22.
[0019]
First, with reference to FIG. 4, the temporary abnormality detection when the IG switch is off will be described. In step 401, the timing of IG switch off is detected by determining whether or not the IG switch is currently turned on from the IG switch on state. When it is detected that the IG switch has been turned off, energization of the coil 24 of the relay 22 is stopped after the electronic throttle control is finished, and the relay switch is turned off (step 402). The normal control is continued as it is unless the timing when the IG switch is turned off, that is, when the IG switch is on.
[0020]
After a predetermined time considering the electrical and mechanical response delay of the relay has elapsed (step 403), the voltage 31 downstream of the switch 23 of the relay 22 is monitored, and the input voltage 31 is set to the predetermined voltage value V ₁ . Compare (step 404). If the state where the value of the input voltage 31 is equal to or higher than the predetermined value V ₁ continues for a predetermined time or longer, it is determined that an abnormality (relay welding) has occurred in the relay (step 405), and a flag indicating that an abnormality has been detected by the temporary abnormality detection (Tentative abnormality detection flag) is set (step 406). That is, it is determined that the relay 22 is abnormal when energization to the electric actuator 10 side is continued for a predetermined time after the relay 22 is set to the non-operating state.
[0021]
The temporary abnormality detection flag can be stored in, for example, a standby RAM. If the value of the input voltage 31 becomes smaller than the predetermined value V ₁ while being shorter than the predetermined time, the flag is not set. The processes in steps 402 to 406 are performed within a short time after the IG switch is turned off. Then, the CPU in the ECU 20 is reset by shutting off the power supply by turning off the IG (step 407).
[0022]
Next, this abnormality detection when the IG switch is turned on will be described with reference to FIG. In step 301, the timing of turning on the IG switch is detected by determining whether or not the IG switch is turned off from the IG switch off state. When the IG switch is already in the on state, not at the timing when the IG is turned on, if the output to the coil 24 of the relay 22 is in the off state, it is turned on (step 307) and normal control continues. It is done.
[0023]
If the IG switch is on, the flag (temporary abnormality flag) indicating the result of the temporary abnormality detection stored in the standby RAM or the like when the IG switch was turned off is determined (step 302). If the temporary abnormality flag is off, the output of the relay 22 to the coil 24 is turned on (step 307), and the routine for normal control is entered. This abnormality detection is performed only when the temporary abnormality flag is on.
[0024]
In this abnormality detection, first, it is confirmed that the output to the coil 24 of the relay 22 is off (step 303), and the voltage 31 downstream of the switch 23 of the relay 22 is monitored. As in the case of the provisional abnormality detection, the input voltage 31 is compared with a predetermined voltage value V ₁ (step 304), and if the state where the value of the input voltage 31 is equal to or higher than the predetermined value V ₁ continues for a predetermined time or longer, 22 determines that an abnormality (relay welding) has occurred (step 305, main abnormality determination). If an abnormality is found in this abnormality detection, the electronic throttle control system is down and control by the motor 11 is prohibited (step 306).
[0025]
In step 304, the value of the input voltage 31 within a predetermined time is smaller than the predetermined value V _1, when the condition of the abnormality determination is no longer satisfied, the relay 22 is determined to have successfully restored ( Step 308), the temporary abnormality flag is cleared (Step 309), and normal control is performed.
[0026]
When relay abnormality detection is performed each time the IG switch is turned on, the time from when the IG switch is turned on until the electronic throttle control can be started is extended each time necessary for relay welding detection, and the throttle valve is started. Cause delay. According to the present invention, as described above, since this abnormality detection is performed when the IG switch is turned on only when a temporary abnormality is detected when the IG switch is turned off last time, the ratio of the delay in throttle start is reduced. Therefore, the driver can start the vehicle more comfortably.
[0027]
(Embodiment 2)
Next, the operation of the abnormality detection device of the present invention and the abnormality detection method will be described in the case where abnormality detection of the electromagnetic clutch 12 for transmitting the driving force of the motor 11 to the throttle valve 14 is performed in the above system. Examples of abnormalities of the electromagnetic clutch 12 include clutch fixation due to mechanical connection such as pin engagement, coil disconnection, and short circuit. In the present specification, the abnormality of the electromagnetic clutch including these various abnormalities will be referred to as “clutch fixation”.
[0028]
FIG. 5 is a flowchart showing the present abnormality detection executed when the IG switch is turned on to detect the fixation of the electromagnetic clutch 12 as an example of abnormality detection. Similarly, FIG. 6 is a flowchart showing temporary abnormality detection that is executed when the IG switch is turned off for detecting the fastening of the electromagnetic clutch 12.
[0029]
First, the temporary abnormality detection when the IG switch is off will be described with reference to FIG. In step 601, the timing of the IG switch off is detected by determining whether or not the IG switch on state has changed to the IG switch off state. When the IG switch OFF is detected, after the electronic throttle control is completed, the energization to the coil of the electromagnetic clutch 12 is stopped and the electromagnetic clutch is turned off (step 602). The normal control is continued as it is unless the IG switch is turned off.
[0030]
After a predetermined time considering the electrical and mechanical response delay of the electromagnetic clutch 12 has elapsed (step 603), the electromagnetic clutch 12 is completely disconnected (if normal). In the uncoupled state of the electromagnetic clutch 12, first, the throttle opening value at the time of starting temporary abnormality detection is detected by the throttle sensor 15 and stored (step 604). The detected throttle opening degree value and opening the initial value V _2. Using the initial opening value V ₂ , the target opening of the throttle valve is set to (V ₂ −ΔV), and energization of the DC motor 11 is started (step 605). The target opening may be set to (V ₂ + ΔV).
[0031]
While the throttle opening is monitored by the throttle sensor 15, it is determined whether or not the throttle sensor value becomes (V ₂ −ΔV / 2) or less within a predetermined time (step 606). When the target opening is set to (V ₂ + ΔV), it is determined whether or not the throttle sensor value is equal to or greater than (V ₂ + ΔV / 2). That is, when rotating the DC motor 11 in the unbound state of the electromagnetic clutch 12, the throttle valve 14 is a criterion whether moved more than half the opening initial value V ₂ of the target opening change amount [Delta] V. Note that the criterion for detecting whether or not the throttle valve 14 moves is not limited to this.
[0032]
When the throttle sensor value becomes (V ₂ −ΔV / 2) or less within a predetermined time, it is determined that an abnormality (clutch fixation) has occurred in the electromagnetic clutch 12 (step 608), and an abnormality has been found in the temporary abnormality detection. Is set (step 609). The flag can be stored in, for example, a standby RAM. If the throttle sensor value does not fall below (V ₂ −ΔV / 2) within a predetermined time, it is determined that the electromagnetic clutch 12 is normal (step 607).
[0033]
Although the temporary abnormality detection of the electromagnetic clutch 12 according to the present embodiment is as described above, actually, the temporary abnormality detection of the relay 22 described in the first embodiment is performed following the detection of the temporary abnormality of the electromagnetic clutch 12 (step 610). ). In step 610, steps 402 to 406 shown in FIG. 4 are executed as necessary.
[0034]
The processes in steps 601 to 610 are performed within a short time after the IG switch is turned off. The CPU in the ECU 20 is reset after the power supply is shut off due to the IG being turned off (step 611).
[0035]
Next, this abnormality detection when the IG switch is turned on will be described with reference to FIG. In step 501, the timing of IG switch on is detected by determining whether or not the current state has changed from the IG switch off state to the IG switch on state. If the IG switch is already in the on state, not at the timing when the IG is currently turned on, if the output to the coil of the electromagnetic clutch 12 is in the off state, it is turned on (step 511), and the normal control is performed. You can continue.
[0036]
As shown in FIG. 5, in actuality, when the IG switch is turned on, first the abnormality detection of the relay 22 described in the first embodiment is performed (step 502). In step 502, steps 302 to 309 shown in FIG. 3 are executed as necessary. Of course, the abnormality detection of the electromagnetic clutch 12 according to the present embodiment may be executed independently.
[0037]
After the relay complete abnormality detection operation is completed, a flag (temporary abnormality flag) indicating the result of the temporary abnormality detection of the electromagnetic clutch 12 performed when the IG switch is turned off previously stored in the standby RAM or the like is determined (step 503). . If the temporary abnormality flag is off, the output to the coil of the electromagnetic clutch 12 is turned on (step 512), and the routine for normal control is entered. This abnormality detection is performed only when the temporary abnormality flag is on.
[0038]
In this abnormality detection, first, it is confirmed that the output to the coil of the electromagnetic clutch 12 is off (step 504).
[0039]
The electromagnetic clutch 12 is completely disengaged (if normal) in the off (non-energized) state. In this state, first, the throttle opening value at the start of the abnormality detection is detected and stored by the throttle sensor 15 (step 505). The detected throttle opening degree value and opening the initial value V _2. Using the initial opening value V ₂ , the target opening of the throttle valve is set to (V ₂ −ΔV), and energization of the DC motor 11 is started (step 506). The target opening may be set to (V ₂ + ΔV) as in the case of temporary abnormality detection.
[0040]
While monitoring the throttle opening by the throttle sensor 15, it is determined whether or not the throttle sensor value becomes (V ₂ −ΔV / 2) or less within a predetermined time (step 507). When the target opening is set to (V ₂ + ΔV), it is determined whether or not the throttle sensor value is equal to or greater than (V ₂ + ΔV / 2). That is, when rotating the DC motor 11 in the unbound state of the electromagnetic clutch 12, the throttle valve 14 is a criterion whether moved more than half the opening initial value V ₂ of the target opening change amount [Delta] V. Note that the criterion for detecting whether or not the throttle valve 14 moves is not limited to this.
[0041]
When the throttle sensor value becomes (V ₂ −ΔV / 2) or less within a predetermined time, it is determined that an abnormality (clutch fixation) has occurred in the electromagnetic clutch 12 (step 510: main abnormality determination). Then, after a warning lamp is turned on to warn the driver of an abnormality, normal control is performed (step 511). The process at the time of clutch fixation will be described later.
[0042]
If the throttle sensor value does not become (V ₂ −ΔV / 2) or less within the predetermined time, it is determined that the electromagnetic clutch 12 is normal (step 508), and the temporary abnormality flag set by the temporary abnormality detection is determined. Is cleared (step 509).
[0043]
The reason for performing the normal control when clutch fixation is detected in this abnormality detection is as follows.
[0044]
The throttle valve is normally biased to the closed side by a return spring, and the motor controls the throttle valve against the biasing force of the return spring. When the electromagnetic clutch is turned off and the driving force from the motor is cut off, the throttle valve is returned to the predetermined closed position by the return spring. When the electromagnetic clutch is fixed, there is a motor detent torque in addition to the torque of the throttle valve itself. Therefore, if the motor is kept in a non-energized state as it is, the throttle valve cannot be reliably operated to the predetermined closed position only by the urging force of the return spring.
[0045]
Therefore, when the motor is de-energized while the electromagnetic clutch is fixed and mechanical throttle valve control (so-called retreat travel mode) is performed, there is a possibility that a valve return failure may occur. In order to avoid such a valve return failure, even if a clutch fixing abnormality occurs, the electromagnetic clutch and the motor are continuously energized to perform normal control, and the driver is warned of the abnormality by lighting a warning lamp. If an abnormality is detected in another part (sensor, motor, etc.) while the electromagnetic clutch is still stuck, a fuel cut is performed to stop the vehicle. .
[0046]
In order to improve the reliability of the system, it is preferable to detect the abnormality of the electromagnetic clutch immediately before starting the throttle valve control. However, if an electromagnetic clutch abnormality is detected each time the IG switch is turned on, the time from when the IG switch is turned on until the electronic throttle control can be started is extended every time necessary to detect the electromagnetic clutch abnormality. This causes a delay in starting the throttle valve. As described above, according to the present invention, since the abnormality is detected when the IG switch is turned on only when a temporary abnormality is detected when the IG switch is turned off last time, the throttle is maintained while maintaining the reliability of the system to some extent. The rate of delay in starting can be reduced. Therefore, the driver can start the vehicle more comfortably.
[0047]
【The invention's effect】
As described above, according to the present invention, the two-stage abnormality detection, that is, the temporary abnormality detection when the engine is stopped and the main abnormality detection when the engine is started, has an opportunity to cause a time delay that hinders instantaneous engine start. It is possible to provide a reduced number of internal combustion engine abnormality detection devices and methods.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a throttle control device to which one embodiment of the present invention is applied.
FIG. 2 is a diagram schematically showing a control system centering on an electric actuator portion of the throttle control device shown in FIG. 1;
FIG. 3 is a flowchart showing this abnormality detection that is performed when the IG switch is turned on in order to detect welding of the relay.
FIG. 4 is a flowchart showing temporary abnormality detection that is performed when the IG switch is turned off in order to detect welding of the relay.
FIG. 5 is a flowchart showing this abnormality detection executed when the IG switch is turned on in order to detect the electromagnetic clutch being stuck.
FIG. 6 is a flowchart showing provisional abnormality detection that is performed when the IG switch is turned off to detect the electromagnetic clutch being stuck.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Electric actuator 11 DC motor 12 Electromagnetic clutch 13 Reduction gear 14 Throttle valve 15 Throttle sensor 20 ECU
21 Driving power source 22 Relay 23 Switch 24 Coil 100 Throttle control device

Claims (6)

An apparatus for detecting an abnormality in an internal combustion engine,
First abnormality detecting means for detecting abnormality of the internal combustion engine when the engine is stopped;
Storage means for storing the result when the first abnormality detection means detects an abnormality;
Second abnormality detection means for detecting abnormality of the internal combustion engine at the next engine start only when the result of detecting abnormality is stored in the storage means;
Including the device. The internal combustion engine includes a throttle control device that drives a throttle valve;
The throttle control device drives a throttle valve using an electric actuator,
Each of the first and second abnormality detecting means detects an abnormality of a relay that supplies power to the electric actuator from a power source;
The apparatus of claim 1. The said 1st and 2nd abnormality detection means judges that this relay is abnormal when energization to the said electric actuator continues for a predetermined time after making the said relay non-operating state. The device described. The internal combustion engine includes a throttle control device that drives a throttle valve;
The throttle control device includes a motor and an electromagnetic clutch that transmits a driving force of the motor to the throttle valve.
The apparatus according to claim 1, wherein each of the first and second abnormality detection means detects an abnormality of the electromagnetic clutch. When the throttle valve is driven when the motor is driven with the electromagnetic clutch disconnected and the electromagnetic clutch opened, the first and second abnormality detection means The throttle control device according to claim 4, wherein the throttle control device is determined to be abnormal. An abnormality detection method for an internal combustion engine,
A first abnormality detection step for detecting an abnormality of the internal combustion engine when the engine is stopped;
Storing the result of the first abnormality detection step;
Determining the stored result at the next engine start;
A second abnormality detection step of detecting abnormality of the internal combustion engine at the time of starting the engine only when it is determined that the result of detection of abnormality in the determination step is stored ;
Including methods.

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