JP2003214234A - Electronic-controlled throttle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic-controlled throttle device which satisfactorily performs the troubleshooting of a throttle system by properly setting determination conditions. <P>SOLUTION: In this electronic-controlled throttle device, when the count value C of a fail timer for counting the continued time of such a state that the absolute value |Δθth| of a deviation between a target throttle opening MθTh and an actual throttle opening θth exceeds a specified value θth1 or more exceeds a determined value C0. When an engine speed Ne is determined to be lower than a specified value Ne1, the count value C of the fail timer is cleared and substantially the execution of determination for trouble of a throttle valve control system is prohibited, and the thresholds (determined value 0) in determination of trouble performed in the other areas are set to severe values not affected by power and voltage. Thus the prevention of erroneous determination of trouble at the start of an engine and the prevention of failure to determine trouble during running are allowed to co-exist. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically controlled throttle device that opens and closes a throttle valve by the driving force of a motor.

[0002]

2. Description of the Related Art In an electronically controlled throttle device that opens and closes a throttle valve by the driving force of a motor, generally, a target throttle opening and an actual throttle opening are compared with each other, and a state where they differ by a predetermined value or more exceeds a set time. If it continues, failure diagnosis control is performed to determine that the system is in failure.

In this type of electronically controlled throttle device, the driving force of the motor that opens and closes the throttle valve changes depending on the power supply voltage of the battery, so the movement of the throttle valve becomes slow when the power supply voltage drops. In such a case, it takes time for the actual throttle opening to follow the target throttle opening, and even if the system is normal, it may be erroneously determined to be a failure.

To address this, for example, Japanese Patent No. 284479.
Japanese Patent Laid-Open Publication No. 2 discloses an electronically controlled throttle valve drive device that detects an abnormality (failure) in a throttle valve control system when the throttle valve is not driven to a predetermined opening within a predetermined determination time. Accordingly, there is disclosed a technique of setting the determination time longer.

[0005]

By the way, as in the technique disclosed in the above-mentioned Japanese Patent No. 2844792, it is necessary to set the failure diagnosis determination time longer according to the decrease in the power supply voltage of the battery. Although it is possible to reduce the erroneous determination of the system as a failure due to the decrease of the value, the condition for the failure diagnosis is relaxed. Therefore, it is desirable that the above-mentioned control is limitedly used when the torque generated by the engine is low and a severe failure diagnosis is not required, such as when the engine is started. It is not preferable that the torque is equal to or more than a predetermined value, and that it is used in a situation where severe failure diagnosis is required on the safety side.

However, the power supply voltage of the battery may be lowered, for example, when the vehicle runs at a low speed with a large number of high load auxiliary equipment such as an air conditioner and headlights operating. In the above-mentioned control that sets the failure diagnosis determination time longer according to the decrease in the power supply voltage,
Even when the vehicle is traveling requiring severe failure diagnosis, there is a possibility that the failure diagnosis determination time may be set long.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an electronically controlled throttle device capable of appropriately setting a determination condition and performing a good failure diagnosis of a throttle system.

[0008]

In order to solve the above problems, the invention according to claim 1 is an electronically controlled throttle device for electrically controlling the opening of a throttle valve provided in an intake path of an engine. A failure determination means for determining a failure of the throttle system when a predetermined detection state in the above condition continues for a determination time or more, and a determination condition setting means for variably setting a condition for failure determination by the failure determination means based on the engine speed. , Is provided.

The electronically controlled throttle device according to a second aspect of the present invention is the electronic control throttle device according to the first aspect of the invention, wherein the determination condition setting means responds to a decrease in the engine speed.
The determination time is set to be long.

The electronically controlled throttle device according to a third aspect of the present invention is the electronic control throttle device according to the first or second aspect of the invention, wherein the determination condition setting means is used when the engine speed is equal to or lower than a predetermined value. It is characterized in that the failure determination means prohibits execution of the failure determination.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 relate to a first embodiment of the present invention, and FIG. 1 is a schematic configuration diagram of an engine control system,
FIG. 2 is a flowchart showing a failure diagnosis routine of the throttle valve control system.

In FIG. 1, reference numeral 1 is an engine,
An injector 3 is interposed in an intake port of the engine 1, and a throttle body 4 forming an intake passage 2 communicating with the intake port is arranged upstream of the intake port. A throttle valve 5 is interposed in the throttle body 4, and the throttle valve 5 is an electronic control unit (EC
U) A motor (in this embodiment, a DC motor) 6 which is driven and controlled by a motor 100 is connected via a gear 7. An intake air amount sensor 8 is provided on the upstream side of the throttle body 4.

The throttle valve 5 is urged by a return spring 10a so as to come into contact with the opener stopper 9 when the motor 6 is not energized. The limp home opening that enables Further, the fully closed position when the throttle valve 5 is controlled to the closed side by the motor 6 against the biasing force of the opener spring 10b is regulated by the fully closed stopper 11. In the figure, the position of the throttle valve 5 is schematically shown by vertical movement.

The ECU 100 has two microcomputers 101 and 102 (hereinafter referred to as a main microcomputer 101 and a sub-microcomputer 102) which are a main microcomputer and a sub microcomputer. The main microcomputer 101 and the sub-microcomputer 102 are capable of bidirectional communication via their communication interfaces. The main microcomputer 101 mainly shares engine control such as fuel injection control and ignition timing control, and the sub-microcomputer 102 controls the motor 6 Drive control (throttle control).

Therefore, the main microcomputer 101 has two systems of accelerator sensors 13 (a main accelerator sensor 13a and a sub accelerator sensor 13b) for detecting the depression amount of the accelerator pedal 12 and a throttle valve 5 opening degree 2 In order to detect signals from the throttle sensor 14 (main throttle sensor 14a, sub-throttle sensor 14b) of the system, intake air amount sensor 8, crank angle sensor 15, cooling water temperature sensor 16, and other engine operating conditions. Signals from sensors (not shown) are input and the engine control amount such as the fuel injection amount from the injector 3 and the ignition timing is calculated. On the other hand, to the sub-microcomputer 102, signals from the two-system accelerator sensor 13 and two-system throttle sensor 14 are input, and also data from the main microcomputer 101 is input, and the target throttle opening Mθth and the actual throttle opening are set. Feedback control of the motor 6 is performed based on the degree θth. In this case, in the sub-microcomputer 102, for example, the deviation Δ between the target throttle opening Mθth and the actual throttle opening θth
Based on θth, the duty ratio Duty for PWM controlling the motor 6 by the motor drive circuit 103 is calculated.

Regarding signals from the two systems of the accelerator sensor 13 and the two systems of the throttle sensor 14, one system is used for normal control, and the other system is used for self-diagnosis. That is, the depression amount of the accelerator pedal 12 is detected by the double-system accelerator sensor 13 and read into the ECU 100, processed by the dual system of the main microcomputer 101 and the sub-microcomputer 102 inside the ECU 100, and then the motor 6 is driven. And control to the optimum throttle opening,
The movement of the throttle valve 5 is controlled by the dual throttle sensor 14
It is detected by and read into the inside of the ECU 100 to monitor whether it is operating normally. In this case, the ECU 100
Fault diagnosis of the throttle valve control system is performed. Specifically, the failure diagnosis of the throttle valve control system is performed by, for example, the sub-microcomputer 102, and the sub-microcomputer 102 malfunctions the throttle valve control system based on the deviation between the target throttle opening Mθth and the actual throttle opening θth. Make a decision. At that time, the sub-microcomputer 102 prohibits the failure determination of the throttle valve control system when the engine speed Ne is less than or equal to a predetermined value. That is, in the present embodiment, the sub-microcomputer 102 has a function as a failure determination unit and a determination condition setting unit.

Main microcomputer 101 inside ECU 100
The output of the dual system by the sub-microcomputer 102 and the sub-microcomputer 102 is output to the motor relay 105 via the matching circuit 104. Then, under normal conditions, the output of the coincidence circuit 104 drives the motor relay 105, and the power from the battery 106 is supplied from the motor relay 105 to the motor 6 via the motor drive circuit 103.

Next, the failure diagnosis of the throttle valve control system performed by the sub-microcomputer 102 will be described with reference to the flowchart of FIG.

This routine is executed every predetermined time. First, in step S101, the engine speed Ne is set.
Is determined to be equal to or greater than the predetermined value Ne1. Here, the predetermined value Ne1 is set, for example, near the idle speed or the speed during cranking. That is, the predetermined value Ne1 is a threshold value for determining whether or not the engine 1 is driven with a low torque, in other words, driving of the engine 1 which does not cause any particular problem even if the failure diagnosis of the throttle valve control system is not strictly performed. It is set as a threshold for determining the state.

Then, in step S101, Ne
When it is determined that ≧ Ne1, step S10
2, the absolute value | Δθth | of the deviation between the target throttle opening degree Mθth and the actual throttle opening degree θth is the predetermined value θt.
It is checked whether or not h1 or more. Here, the predetermined value θth
1 is set based on the deviation of the actual throttle opening θth from the target throttle opening Mθth that can occur when the throttle valve control system is operating normally,
It is obtained in advance by experiments or the like.

Then, in step S102, | Δ
When it is determined that θth | ≧ θth1, the process proceeds to step S103, Ne ≧ Ne1, and | Δθth
After incrementing the count value C of the fail timer indicating the duration of the state of | ≧ θth1 (C ← C + 1), the process proceeds to step S105.

On the other hand, in step S101, Ne <N
If it is determined to be e1, or step S10
If it is determined that | Δθth | <θth1 in step 2, the process proceeds to step S104, where the fail timer count value C is cleared (C ← 0), and then step S1.
Go to 05.

In step 105, it is checked whether or not the count value C of the fail timer is larger than the judgment value C0 for judging the failure. That is, in step S105,
By comparing the count value C and the judgment value C0, N
It is checked whether the duration of the state of e ≧ Ne1 and | Δθth | ≧ θth1 is longer than the predetermined time defined by the determination value C0. Here, the time defined by the judgment value C0 is set to a relatively short judgment time (for example, 0.5 seconds) in order to realize a severe failure judgment of the throttle valve control system.

Then, in step S105, C>
If it is determined to be C0, the routine proceeds to step S106, and it is determined that there is some abnormality in the throttle valve control system, and then the routine exits.

On the other hand, in step S105, C ≦ C
If it is determined to be 0, the process proceeds to step S107, and after determining that the throttle valve control system is operating normally, the routine exits.

According to such an embodiment, when diagnosing a failure of the throttle valve control system, it is possible to prevent erroneous determination of a failure at engine startup and prevent failure of failure determination during traveling. .

That is, in the control of the throttle valve 5, there is no particular problem even if a severe failure determination is not performed at the time of engine start, and rather, from the viewpoint of preventing frequent occurrence of erroneous determination of failure, failure determination is performed. It is better not to do it. On the other hand, from a safety point of view, it is desirable to perform a severe failure determination during traveling or the like even if there is an erroneous determination of a failure due to a decrease in the power supply voltage. By the way, while the engine speed Ne is low at the time of starting (cranking) the engine 1 where the power supply voltage of the battery 106 is most likely to drop, the engine speed Ne is equal to or higher than a predetermined value regardless of the power supply voltage at the time of running. Is secured. Therefore, in the present embodiment, when it is determined that the engine speed Ne is lower than the predetermined value Ne1, the count value C of the fail timer is cleared and execution of the failure determination of the throttle valve control system is substantially prohibited. Along with
Threshold value for failure determination (determination value C
By setting 0) to a severe value irrespective of the power supply voltage, it is possible with simple control to prevent both an erroneous determination of a failure at engine startup and a failure to omit a failure determination at the time of traveling. .

Next, FIG. 3 is a flow chart showing a failure diagnosis routine of the throttle valve control system according to the second embodiment of the present invention. It should be noted that the present embodiment is for performing a failure diagnosis of the throttle valve control system by a control method different from that of the above-described first embodiment.

The failure diagnosis of the throttle valve control system executed by the sub-microcomputer 102 will be described below with reference to the flowchart of FIG.

This routine is executed every predetermined time. First, in step S201, it is checked whether or not the duty ratio Duty (output Duty) for controlling the motor 6 is a predetermined value Duty1 or more.

Here, the predetermined value Duty1 is set to the maximum value that can be taken, for example, when the throttle valve control system is normal, and is obtained in advance by experiments or the like. by the way,
The sub-microcomputer 102 determines the target throttle opening Mθth and the actual throttle opening θ due to an abnormality in the throttle control system or the like.
When the deviation from th becomes large, the duty ratio Duty is controlled to be high so that a large current is applied to the motor 6. Therefore, in such a case, the absolute value of the duty ratio |
Duty | exceeds the predetermined value Duty1.

Duty is calculated as a positive value when the torque that operates the throttle valve is generated, and as a negative value when the torque that operates the throttle valve is generated.

Therefore, in step S201, | Du
When it is determined that ty | ≧ Duty1, it is determined that there is a high possibility that an abnormality has occurred in the throttle valve control system, the process proceeds to step S202, and | Duty | ≧ Dut
After incrementing the count value C of the fail timer indicating the duration of the state of y1 (C ← C + 1), the process proceeds to step S204.

On the other hand, in step S201, | Du
If it is determined that ty | <Duty1, after clearing the count value C of the fail timer (C ← 0),
It proceeds to step S204.

In step S204, the engine speed N
It is checked whether e is a predetermined value Ne1 or more. here,
The predetermined value Ne1 is set, for example, near the idle speed or the speed during cranking. That is, the predetermined value Ne1 is a threshold value for determining whether or not the engine 1 is being driven with a low torque, that is, a driving state of the engine 1 that does not cause a problem even if the failure diagnosis of the throttle valve control system is not strictly performed. It is set as a threshold for determination.

Then, in step S204, Ne
If it is determined that <Ne1, step S20
In step 5, it is checked whether the count value C of the fail timer is the judgment value C1 or more for failure judgment. That is, in step S205, the count value C and the judgment value C1
By comparing and, it is checked whether or not the duration of the state of | Duty | ≧ Duty1 is longer than the predetermined time defined by the determination value C1. Here, the time defined by the judgment value C1 is set to a comparatively long judgment time (for example, 1 second).

Then, in step S205, C ≧
If it is determined to be C1, the process proceeds to step S207, and it is determined that there is some abnormality in the throttle valve control system, and then the routine exits.

On the other hand, in step S205, C <C
If it is determined to be 1, the process proceeds to step S208, and it is determined that the throttle valve control system is operating normally, and then the routine exits.

In step S204, Ne <
If it is determined to be Ne1, step S206.
Then, it is checked whether or not the count value C of the fail timer is a judgment value C2 or more for failure judgment. That is, in step S206, the count value C and the judgment value C2
By comparing and, it is checked whether or not the duration of the state of | Duty | ≧ Duty1 is longer than the predetermined time defined by the determination value C2. Here, the time defined by the judgment value C2 is set to a relatively short judgment time (for example, 0.5 seconds) in order to realize a severe failure judgment.

Then, in step S206, C ≧
If it is determined to be C2, the routine proceeds to step S207, it is determined that there is some abnormality in the throttle valve control system, and then the routine exits.

On the other hand, in step S206, C <C
If it is determined to be 2, the process proceeds to step S208, and it is determined that the throttle valve control system is operating normally, and then the routine exits.

According to such an embodiment, as in the case of the above-described first embodiment, in the failure diagnosis of the throttle valve control system, the erroneous determination of the failure at the engine start is prevented, and the failure at the time of traveling or the like. It is possible to achieve both prevention of determination omission.

In this case, even when Ne <Ne1,
Since the failure determination is performed by comparing the determination value C1 that defines a relatively long determination time with the count value C of the fail timer, the failure determination can be performed for all operating states of the engine 1.

Next, FIGS. 4 and 5 relate to a third embodiment of the present invention, FIG. 4 is a flowchart showing a failure diagnosis routine of a motor relay, and FIG. 5 shows a relationship between an engine speed and a judgment value. It is a map shown. In this embodiment, the count value C of the fail timer is determined more finely than in the above-described second embodiment. Also,
In the present embodiment, an example of failure diagnosis specialized for the motor relay 105 is shown as the failure diagnosis of the throttle system.

Since the exciting coil of the motor relay 105 has self-inductance, it takes a predetermined time to overcome the spring force of the contact after being energized and increase the current to a current value at which the contact can be attracted. Further, the motor drive circuit 103 has a capacitor and the like for absorbing noise. Therefore, after the motor relay 105 is turned on, it takes a predetermined time according to the power supply voltage of the battery 106 for the voltage (that is, the motor power supply voltage) V supplied to the motor drive circuit 103 to reach the predetermined value V1.
When a disconnection, a connection failure or the like occurs inside the motor relay 105, the motor power supply voltage V does not rise to the predetermined value V1 within a predetermined time even if the motor relay 105 is turned on. Therefore, the motor power supply voltage V should be monitored. Thus, the failure diagnosis of the motor relay 105 can be performed.

The failure diagnosis of the throttle valve control system executed by the sub-microcomputer 102 will be described below with reference to the flowchart of FIG.

This routine is executed every predetermined time. First, in step S301, the motor relay 105
It is checked whether or not the output (motor relay output) from the matching circuit 104 with respect to is in the ON state.

Then, in step S301, the output from the matching circuit 104 for the motor relay 105 is O.
If it is determined to be in the N state, step S302.
Then, it is checked whether the motor power supply voltage V from the motor relay 105 is larger than a predetermined value V1.

Then, in step S302, V≤
If it is determined to be V1, the process proceeds to step S303, and the fail timer count value C indicating the elapsed time from when the motor relay 105 is turned on until the motor power supply voltage V reaches V1 is incremented (C ← C + 1). After that, the process proceeds to step S305.

On the other hand, if it is determined in step S301 that the motor relay output is OFF, or V
If it is determined that> V1, step S304
Proceed to and clear the count value C of the fail timer (C ←
After 0), the process proceeds to step S305.

In step S305, a judgment value CNe for making a failure judgment based on the count value C is set with interpolation calculation based on the engine speed Ne, for example, with reference to the map shown in FIG. The map in this case is obtained in advance by experiments or the like and is stored in the ROM of the sub-microcomputer 102, and the lower the engine speed Ne, the higher the determination value CNe is set. In other words, the determination value CNe is set to a more severe value as the engine speed increases.

In a succeeding step S306, it is checked whether or not the count value C of the fail timer is not less than the judgment value CNe.

Then, in step S306, C ≧ C
If it is determined to be Ne, the process proceeds to step S307, and it is determined that the motor relay 105 has some abnormality, and then the routine exits.

On the other hand, in step S306, C <C
If it is determined to be Ne, the process proceeds to step S308, the motor relay 105 is determined to be operating normally, and then the routine is exited.

According to such an embodiment, in the failure diagnosis of the motor relay 105, it is possible to prevent both an erroneous determination when the engine is started and a determination omission when the vehicle is running.

In this case, by variably setting the determination value CNe according to the engine speed Ne, more detailed failure diagnosis can be performed for all operating states of the engine 1.

In each of the above-described embodiments, an example in which the sub-microcomputer 102 performs the fault diagnosis of the throttle system has been described.
The main microcomputer 101 may be used instead of the sub-microcomputer 102.

It is needless to say that the control described in each of the above-mentioned embodiments may be appropriately combined to perform the failure diagnosis of the throttle system.

[0059]

As described above, according to the present invention, it is possible to appropriately set the determination condition and perform a good failure diagnosis of the throttle valve control system.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an engine control system according to a first embodiment of the present invention.

FIG. 2 is a flow chart showing a failure diagnosis routine of the throttle valve control system.

FIG. 3 is a flowchart showing a failure diagnosis routine of a throttle valve control system according to the second embodiment of the present invention.

FIG. 4 is a flowchart showing a motor relay failure diagnosis routine according to the third embodiment of the present invention.

FIG. 5 is a map showing the relationship between the engine speed and the judgment value.

[Explanation of symbols]

1 ... Engine 5 ... Throttle valve 15 ... Crank angle sensor 101 ... Main microcomputer 102 ... Sub-microcomputer (fault determination means, determination condition setting means) 103 ... Motor drive circuit 104 ... Matching circuit 105 ... Motor relay 106 ... Battery C ... Count value CNe ... Judgment value C0 ... Judgment value C1 ... Judgment value C2 ... Judgment value Duty ... Duty ratio Duty1 ... Predetermined value Mθth ... Target throttle opening Ne ... Engine speed Ne1 ... Predetermined value V ... Motor power supply voltage V1 ... Predetermined value Δθth ... Deviation θth ... Actual throttle opening θth1 ... Predetermined value

Continued front page    F term (reference) 3G065 CA33 CA39 DA05 DA15 EA01                       EA03 EA12 FA12 GA05 GA09                       GA10 GA41 GA46 HA06 HA19                       HA21 HA22 JA04 JA09 JA11                       KA02 KA15 KA16                 3G301 JB01 JB02 JB09 KA01 KA07                       LA03 LB01 MA11 NA08 NB03                       NB15 NC02 ND02 NE23 PA01Z                       PA11Z PE01Z PE03Z PE08Z                       PF03Z

Claims (3)

[Claims] 1. An electronically controlled throttle device for electrically controlling the opening of a throttle valve provided in an intake path of an engine, wherein a failure of the throttle system is determined when a predetermined detection state of the throttle system continues for a determination time or longer. An electronically controlled throttle device, comprising: a failure determination means for performing a failure determination; and a determination condition setting means for variably setting a condition for failure determination by the failure determination means based on an engine speed. 2. The electronically controlled throttle device according to claim 1, wherein the determination condition setting means sets the determination time longer according to a decrease in engine speed. 3. The determination condition setting means prohibits execution of the failure determination by the failure determination means when the engine speed is equal to or lower than a predetermined value. Electronically controlled throttle device.