JP2000337196A - Throttle control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the throttle control device of an internal combustion engine which can carry out the most suitable fail safe responding to the abnormality of a throttle control device. SOLUTION: When the fail flag XFAIL1 for showing the abnormality of a first throttle control system and the abnormality of a second throttle control system is '1' (S7), or when the fail flag XFAIL4 for showing a valve block state is '1', the electrification of an advance motor is discontinued (S9). When the fail flag XFAIL2 showing the abnormality of an accelerator interlocking mechanism is '1', the throttle opening order value at the fail time is set and the throttle valve is controlled by this order value (S8).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle control device for an internal combustion engine.

[0002]

2. Description of the Related Art In recent years, there have been proposed a large number of throttle control devices for electrically controlling the opening of a throttle valve of an internal combustion engine with a motor or the like. Therefore, there is an advantage that it is possible to appropriately cope with the driving state of the vehicle such as an acceleration request. In these throttle control devices, the throttle valve is different from a general one in which the throttle valve is mechanically connected to the accelerator pedal. When an abnormality occurs in the control system, the throttle valve is driven in the opening direction regardless of the accelerator operation amount. There was a possibility.

Therefore, as a throttle control device for an internal combustion engine capable of coping with the abnormality of the throttle control system, for example, JP-A-62-35039 and JP-A-60-1
No. 59346 can be mentioned.

In the former throttle control device, when an abnormality occurs in the throttle control system while the engine speed exceeds 2000 rpm, the fuel cut for each cylinder is intermittently performed to limit the engine speed to 2000 rpm or less. Therefore, a sudden increase in the engine torque is prevented.

Further, the latter throttle control device considers that an abnormality has occurred in the control system, for example, when the throttle valve is open even though the accelerator is not operated, and determines whether the four-cylinder engine of the internal combustion engine has failed. The three cylinders are stopped by fuel cut to suppress the engine torque. Further, when the accelerator operation is performed, one cylinder during the fuel cut is recovered, and the engine torque enough to continue the running of the vehicle is secured. are doing. In other words, in the above two types of throttle control devices, when an abnormality occurs in the throttle control system, a sudden increase in engine torque is suppressed by fuel cut.

[0006]

SUMMARY OF THE INVENTION A throttle control device sets a throttle opening command value of a throttle valve of an internal combustion engine based on an accelerator operation amount, and controls a throttle valve by a motor based on the throttle opening command value. ing. Further, depending on the location of the abnormality of the throttle control device, the throttle control may be possible depending on the degree of the abnormality. However, in the above prior art, only the abnormality of the throttle control system is detected, and other abnormal parts, for example, the abnormality of the accelerator system are not detected.

Further, in the above prior art, when an abnormality is detected, the throttle control is stopped, and the number of fuel supply cylinders is reduced to adjust the engine torque. However, control of the engine torque by reducing the number of fuel supply cylinders has a large variation in torque when the number of reduced cylinders is switched. Therefore, it is preferable to perform fail-safe by throttle control if possible.

Accordingly, an object of the present invention is to provide a throttle control device for an internal combustion engine capable of performing an optimum fail-safe according to an abnormality of the throttle control device.

[0009]

According to a first aspect of the present invention, there is provided a throttle control device for an internal combustion engine, wherein a plurality of abnormality detection means detect an abnormality of the throttle control means, and the fail-safe means is detected by a plurality of abnormality detection means. Perform fail-safe processing according to the degree of abnormality performed.

As a result, it is possible to perform an optimum fail-safe according to the abnormality of the throttle control device.

In particular, as a plurality of abnormality detecting means, a plurality of abnormality detecting means include a throttle system abnormality detecting means for detecting an abnormality related to a throttle valve opening and an accelerator system abnormality detecting means for an accelerator operation amount. A valve lock detecting means for detecting a lock state of the throttle valve. When an abnormality is detected by the throttle system abnormality detecting means or the valve lock detecting means, it is determined that the throttle control is impossible, and the motor is stopped. The throttle opening command value set based on the accelerator operation amount when an abnormality is detected by the system abnormality detecting means may be set to a value smaller than the normal state.

Thus, when the throttle control is impossible, the throttle control is stopped. However, in the case of an accelerator system abnormality in which the throttle control can be performed, the fail-safe operation is performed by the throttle control. Fail-safe can be achieved without causing torque variation as compared with fail-safe.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A throttle control device for an internal combustion engine according to one embodiment of the present invention will be described below. FIG. 1 is a schematic configuration diagram showing a throttle control device for an internal combustion engine according to one embodiment of the present invention, and FIG. 2 is a perspective view showing the vicinity of a throttle valve to which the throttle control device for an internal combustion engine according to one embodiment of the present invention is applied. FIG.

First, a schematic configuration of an internal combustion engine to which the throttle control device of the present embodiment is applied will be described.

As shown in FIG. 1, the internal combustion engine 1 is configured as a V-type six-cylinder four-cycle internal combustion engine. An air cleaner 3 is provided on the upstream side of the intake passage 2 of the internal combustion engine 1, and an air flow meter 4 for detecting the amount of intake air is provided on the downstream side of the air cleaner 3.

A throttle valve 5 is provided downstream of the air flow meter 4 in the intake passage 2, and the amount of intake air supplied to the internal combustion engine 1 is adjusted according to the opening and closing of the throttle valve 5. The intake passage 2 is connected to each cylinder of the internal combustion engine 1 via an intake manifold 6, and intake air from the intake passage 2 is distributed and supplied to each cylinder via the intake manifold 6.

Intake manifold 6 is provided with an injector 7 corresponding to each cylinder, and fuel injected from each injector 7 is mixed with intake air and supplied to each cylinder. The air-fuel mixture is introduced into the combustion chamber 9 of each cylinder with the opening and closing of the intake valve 8, burns by the ignition of the ignition plug 10, and pushes down the piston 11 to apply torque to the crankshaft 12. The exhaust gas after combustion is discharged to the outside via an exhaust passage 14 with opening and closing of an exhaust valve 13. A crank angle sensor 15 is provided at a position close to the crankshaft 12, and outputs a pulse signal every 30 degrees of the crank angle.

Next, the configuration around the throttle valve of the internal combustion engine configured as described above will be described.

As shown in FIG. 2, the configuration of the throttle control device of this embodiment includes a motor drive mechanism 21 for electrically opening and closing the throttle valve 5 with a DC motor 31 and a throttle valve 5. It is roughly divided into an accelerator interlocking mechanism 22 for mechanically opening and closing in conjunction with an accelerator operation.

First, the motor drive mechanism 21 will be described.
A throttle shaft 23 extends horizontally through the intake passage 2, and is attached to the throttle shaft 23. The throttle valve 5 is fixed to the throttle shaft 23 in the intake passage 2. With the rotation of the throttle shaft 23, the throttle valve 5 opens and closes the intake passage 2 to adjust the amount of intake air. here,
The rotation direction of the throttle shaft 23 when opening the inside of the intake passage 2 to the throttle valve 5 is defined as an opening direction, and the rotation direction of the throttle shaft 23 when opening the intake passage 2 is defined as a closing direction.

Both ends of the throttle shaft 23 project left and right (left and right in the figure) from the intake passage 2, and a stopper lever 24 is fixed to the left end thereof. Stopper lever 2
4 is provided with an L-shaped bent portion 24a.
Two valve springs 25 are connected to 4a, and always bias the throttle shaft 23 in the opening direction. The bent portion 24a
The fully closed position stopper 26 is disposed at a position close to the bent position 24a of the stopper lever 24 when the throttle valve 5 rotates to the fully closed position.
To restrict further rotation.

On the right side of the throttle shaft 23, a quarter-circle driven gear 28 is rotatably mounted via a bearing 27. The driven gear 28 is a pair of large and small intermediate gears for reduction. The gear 29 meshes with the drive gear 30 via the gear 29.

The driving gear 30 is an output shaft 3 of a DC motor 31.
1a, the DC motor 31 rotationally drives the driven gear 28 in the closing direction via the driving gear 30 and the intermediate gear 29. A hook 28a protrudes from one side of the driven gear 28. The return spring 32 connected to the hook 28a always opens the driven gear 28 in the opening direction, that is, in the direction opposite to the driving direction of the DC motor 31. It is energizing.

On the right side of the driven gear 28, a latch lever 33 is fixed to the throttle shaft 23, and the latch lever 33 is provided with an L-shaped bent portion 33a. This bent portion 33a is located on the closed side of the latching portion 28a of the driven gear 28,
The throttle shaft 23 is rotated and urged in the opening direction by the valve spring 25 to come into contact with the engaging portion 28a.

Therefore, when the DC motor 31 is energized and generates torque, the return spring 32 and the valve spring 25
The driven gear 28 is rotated in the closing direction against the urging force of
The throttle valve 5 is driven to rotate in the closing direction together with the latch lever 33 and the throttle shaft 23. When the energization of the DC motor 5 is stopped, the valve spring 25 urges the throttle valve 5 in the opening direction, and the return spring 32 urges the driven gear 28 in the opening direction.

A throttle opening sensor 34 is provided at the right end of the throttle shaft 23. The opening sensor 34 outputs a voltage Vth corresponding to the opening of the throttle valve 5.

On the other hand, the accelerator interlocking mechanism 22 will be described. A guard shaft 41 is rotatably supported on the left side of the throttle shaft 23 so as to be located coaxially, and is fixed to the guard shaft 41. The accelerator lever 42 is connected to an accelerator pedal 44 of the vehicle via a control cable 43.
Is linked to A guard lever 45 is fixed to the right end of the guard shaft 41, and the guard lever 45 is constantly urged in the closing direction by a guard spring 46 connected to one side.

The urging force of the guard spring 46 is set sufficiently higher than the urging force of the two valve springs 25 described above. When the driver depresses the accelerator pedal 44, the guard shaft 41 and the guard lever 45 are operated to rotate in the opening direction against the urging force of the guard spring 46 together with the accelerator lever 42 via the control cable 43. You.

An accelerator position sensor 47 is provided on the accelerator pedal 44, and the throttle valve 5 is opened and closed by the DC motor 31 based on the accelerator operation amount Ap detected by the accelerator position sensor 47, as described later. . The throttle opening θth at this time
Is generally increased with an increase in the accelerator operation amount Ap. Therefore, when the accelerator operation is performed, the throttle valve 5 is electrically opened and closed by driving the DC motor 31 on the one hand, and The guard lever 45 is mechanically rotated in the same direction by the transmission of the control cable 43.

An L-shaped bent portion 45a is provided on one side of the guard lever 45. The bent portion 45a is located on the open side of the bent portion 24a of the stopper lever 24. A predetermined amount of play is set between the two bent portions 45a and 24a, and this play is always ensured when the throttle shaft 23 and the guard shaft 41 rotate in the same direction.

As will be described later, when an abnormality occurs in the throttle control system or a valve lock occurs, the energization of the DC motor 31 is stopped, and the urging force of the valve spring 25 causes the throttle valve 5 to rotate in the opening direction. Is done. At this time, the bent portion 24a of the stopper lever 24 comes into contact with the bent portion 45a of the guard lever 45 to restrict the opening of the throttle valve 5 further. It is restricted to be less than the moving angle (hereinafter, simply referred to as “guard position”).

When the guard shaft 41 is rotated by the accelerator operation as described above, the stopper lever 24 rotates together with the guard lever 45 in the same direction, and the throttle valve 5 is opened and closed. That is, after that, the throttle valve 5 is mechanically opened and closed by the accelerator interlocking mechanism 22, and the traveling of the vehicle can be continued. The guard shaft 4
A guard position sensor 48 is provided at the left end of 1 to detect a guard position θmg.

The guard lever 45 has an arc-shaped long hole 45b centered on the guard shaft 41.
The distal end of the operation rod 49a of the diaphragm actuator 49 is movably fitted along the long hole 45b. During normal running, as shown in the figure, the operation rod 49a of the diaphragm actuator 49 is held in an extended state, and the guard lever 45 rotates according to the accelerator operation while being allowed by the long hole 45b.

During cruise control traveling, the operating rod 4 of the diaphragm actuator 49
9a is contracted, and the guard lever 45 is rotated in the opening direction. Therefore, even if the accelerator is not operated, the guard position is greatly changed in the opening direction, so that the DC motor 31 is not operated.
By operating the throttle valve 5 in the opening direction, the traveling speed set by the driver can be maintained.

The engagement claw 45c formed integrally with the guard lever 45 is provided on the operating rod 50 of the thermowax 50.
a of the operating rod 50 of the thermowax 50
a expands and contracts according to the cooling water temperature of the internal combustion engine. For example, as shown in the figure, when the cooling water temperature is high, such as after completion of warm-up, the operating rod 50a extends so that the guard lever 45 rotates in the closing direction.

When the temperature of the cooling water is low, such as during a cold start, the operating rod 50a contracts so that the guard lever 45 rotates in the opening direction. Then, as in the case of the cruise control running, the DC motor 3
By operating the throttle valve 5 in the opening direction at 1, the idle-up can be performed.

Next, the operation of the mechanism around the throttle valve will be described.

FIG. 3 is an explanatory view schematically showing the operation principle around a throttle valve to which the throttle control device for an internal combustion engine according to one embodiment of the present invention is applied. In this figure, the upper part is the opening direction of the throttle valve 5, and the lower part is the closing direction.

As shown in the figure, the guard lever 45 is urged in the closing direction by a guard spring 46. The guard position of the guard lever 45 depends on the operation amount of the accelerator pedal 44, the displacement of the operation rod 49a of the diaphragm actuator 49, and the like. Amount, operation rod 50 of thermo wax 50
It is determined by the displacement of a. Then, for example, when the accelerator pedal 44 is depressed by the driver, the guard lever 45 is operated in the opening direction against the urging force of the guard spring 46 (pulled upward in the figure), and the guard position changes in the opening direction. .

The throttle valve 5 is urged in the opening direction by a valve spring 25.
Is urged in the opening direction by the return spring 32. D
When the C motor 31 drives the throttle valve 5 in the closing direction, the urging forces of the valve spring 25 and the return spring 32 act in a direction that impedes the driving. Therefore, both springs 2
The opening of the throttle valve 5 is determined by the balance between the urging forces of the DC motors 5 and 32 and the torque of the DC motor 31, and the throttle valve 5 is closed as the torque of the DC motor 31 increases.

When the energization of the DC motor 31 is stopped, the valve spring 25 urges the throttle valve 5 in the opening direction, and the return spring 32 drives the driven gear 2.
8 is urged in the opening direction.

Next, the electrical configuration of the throttle control device of this embodiment will be described. As shown in FIG. 1, the electronic control unit 61 of the throttle control unit includes a CPU 62, a ROM 6
3, RAM 64, injector drive circuit 65, lamp drive circuit 68, A / D conversion circuit 66, and D / A conversion circuit 6
7. The ROM 63 stores various programs for controlling the operation of the internal combustion engine 1, for example, programs for controlling the opening of the throttle valve 5 and controlling the fuel injection of the injector 7, and the CPU 62 executes processing according to these programs. Also, the RAM 64 is C
The processing data executed by the PU 62 is temporarily stored.

The CPU 62 includes the air flow meter 4
The intake air amount Qa detected at is input and
The pulse signal from the crank angle sensor 15 and the output voltage Vth of the throttle opening sensor 34 (= throttle opening θt)
h), the accelerator operation amount Ap detected by the accelerator position sensor 47 and the guard position θmg detected by the guard position sensor 48 are each an A / D conversion circuit 66.
Is converted into a digital value and input.

The CPU 62 determines, for example, the engine speed Ne calculated from the pulse signal of the crank angle sensor 15.
The fuel injection amount required by the internal combustion engine 1 at the present time is calculated based on the current and the intake air amount Qa, and a control signal having a pulse width corresponding to the fuel injection amount is output to the injector drive circuit 65.

The CPU 62 calculates the number of fuel cut cylinders Nfc (0 to 6) when an abnormality in the throttle control system described later or a valve lock occurs, and shifts to a specific cylinder in accordance with the number of fuel cut cylinders Nfc. Output of the control signal is stopped. The injector drive circuit 65 includes a CPU
The injector 7 is energized for a time corresponding to the pulse width input from the cylinder 62 to inject a required amount of fuel, and fuel injection is stopped for a specific cylinder to which no control signal is input from the CPU 62.

On the other hand, the CPU 62 determines the accelerator operation amount Ap.
A throttle opening command value θcmd which is a target value of the throttle opening control is determined based on the engine speed Ne and the engine speed Ne, and a throttle command voltage Vcmd corresponding to the throttle opening command value θcmd is determined. Further, the CPU 62
Outputs a control signal to a lamp drive circuit 68 to turn on a warning lamp 69 provided in the driver's seat of the vehicle when various abnormalities described later occur in the throttle function of the internal combustion engine 1.

The DC motor drive circuit 71 of the throttle control device includes a PID control circuit 72 and a PWM (pulse width modulation).
It comprises a circuit 73 and a driver 74. The throttle command voltage Vcm calculated by the CPU 62 as described above
The d is converted into an analog value by the D / A conversion circuit 67 and input to the PID control circuit 72. PID control circuit 7
The DC motor 31 performs a proportional / integral / differential operation based on the throttle command voltage Vcmd and the output voltage Vth of the throttle opening sensor 34 in order to reduce the deviation.
Is calculated. The PWM circuit 73 inputs the calculated control amount and converts the control amount into a corresponding duty ratio signal.
The C motor 31 is driven to adjust the actual throttle opening θth to the throttle opening command value θcmd. The duty ratio signal of the PWM circuit 73 is also input to the CPU 62.

<< Throttle Control Process >> Next, the throttle control process executed by the CPU of the throttle control device for an internal combustion engine configured as described above will be described.

FIG. 4 is a flowchart showing a throttle control routine executed by the CPU of the internal combustion engine throttle control apparatus according to one embodiment of the present invention. FIG. 5 is a flowchart showing the throttle control routine of the internal combustion engine according to one embodiment of the present invention. 6 is a flowchart showing a fail determination routine executed by the CPU, and FIG.
FIG. 7 is a flowchart showing a first routine for determining an abnormality of a throttle control system executed by a CPU of a throttle control device for an internal combustion engine according to an embodiment of the present invention. FIG. 7 is a flowchart showing a throttle control device for an internal combustion engine according to an embodiment of the present invention. FIG. 9 is an explanatory diagram showing a control delay of an actual throttle opening with respect to a throttle opening command value of FIG.

FIG. 8 is a flowchart showing a second throttle control system abnormality determination routine executed by the CPU of the throttle control device for an internal combustion engine according to one embodiment of the present invention, and FIG. 9 is an embodiment of the present invention. FIG. 10 is a flowchart showing an accelerator interlocking mechanism abnormality determination routine executed by the CPU of a certain internal combustion engine throttle control device. FIG. 10 shows a spring breakage determination routine executed by the CPU of the internal combustion engine throttle control device according to one embodiment of the present invention. Flowchart shown,
FIG. 11 is a flowchart showing a valve block determination routine executed by the CPU of the throttle control device for an internal combustion engine according to one embodiment of the present invention.

The throttle control routine shown in FIG.
Executed every c. First, the CPU 62 executes a fail determination process in step S1.

<Fail Judgment Routine> When the failure judgment routine is called, the CPU 62 proceeds to step S10 in FIG. Then, the first throttle control abnormality determination processing is performed in step S10, the second throttle control abnormality determination processing is performed in step S20, the accelerator interlocking mechanism abnormality determination processing is performed in step S30, and the spring breakage determination processing is performed in step S40. In step S50, a valve block determination process is executed.

<First Throttle Control System Abnormality Determination Routine> Hereinafter, the details of each abnormality determination process will be described. When the first throttle control system abnormality determination routine is called in step S10, the CPU 62 proceeds to the step of FIG. Move to S11. First, in step S11, it is determined whether the fail flag XFAIL1 indicating the occurrence of an abnormality in the throttle control system has already been set by the first throttle control system abnormality determination routine or a second throttle control system abnormality determination routine to be described later. Is determined.

When the fail flag XFAIL1 is not set, the current throttle opening (hereinafter simply referred to as "control estimation") in step S12 is determined based on the throttle opening command value θcmd which is the target value of the throttle opening control. Θcmdo) is calculated according to the following equation.

Θcmdo = K1 · θcmdi + K2 · θ
cmdi-1 + K2 ・ θcmdoi-1 + K3 ・ θcm
doi-2 Here, K1 to K3 are preset constants, and θc
mdi is the current throttle opening command value, θcmdi-1
Is the previous throttle opening command value, θcmdoi-1 is the previous estimated control throttle opening, and θcmdi-2 is the previous estimated control throttle opening.

As shown in FIG. 7, when the throttle opening command value θcmd changes, the actual control estimated throttle opening θcmd follows up with a predetermined delay.
It is determined by the characteristics of the DC motor 31 and its drive circuit 71. Then, the above-described equation is obtained by using the DC motor 31
And the drive circuit 71 is approximated by a second-order lag filter, and the control estimated throttle opening θcm calculated from the throttle opening command value θcmd according to this equation.
do includes an error that the throttle control system currently has.

Next, in step S13, the CPU 62 sets the absolute value of the difference between the control estimated throttle opening θcmdo and the actual throttle opening θth converted from the output voltage Vth of the throttle opening sensor 34 to a predetermined value set in advance. It is determined whether it is less than θa. If an affirmative determination is made in step S13 (| θcmdo−θth | <θa), the counter Ca for counting the duration of the abnormal state is reset in step S14. Further, step S15
Then, the throttle opening θth at this time is stored in the RAM 64 as the fail-time throttle opening θsave, and the process proceeds to step S16.

When a negative determination is made in step S13 (| θ cmdo−θth | ≧ θa), step S1
At step 7, the counter Ca is incremented by "+1", and the routine goes to step S16. Then, in step S16, it is determined whether or not the counter Ca is smaller than a predetermined value KCa, and when a positive determination is made (Ca <KCa),
When this routine is terminated and a negative determination is made (Ca
≧ KCa), the failure flag XF
AIL1 is set, and this routine ends.

Here, the control estimated throttle opening θcmdo, which is the throttle opening for control, should originally match the actual throttle opening θth. Therefore,
As described above, if a certain degree of difference continuously occurs between the control estimated throttle opening θcmdo and the actual throttle opening θth, an abnormality occurs in the throttle control system for some reason and the DC motor It can be considered that the throttle opening control by 31 is not normally executed. Therefore, at this time, the CPU 62 determines that the throttle control system has failed, and the fail flag XF
AIL1 is set.

The fail flag XFAIL1
After the setting, if the first throttle control system abnormality determination routine is executed again, an affirmative determination is made in step S11 and the routine is immediately terminated. Therefore,
The process of step S15 is not executed, and the throttle opening θth at the time when the fail determination is made is stored in the RAM 64.
It continues to be stored as the fail-time throttle opening θsave.

<Second Throttle Control System Abnormality Determination Routine> When the second throttle control system abnormality determination routine is called in step S20 of the fail determination routine, the CPU 62 proceeds to step S21 in FIG. Step S1 of the first throttle control system abnormality determination routine
Similarly to 1, it is first determined in step S21 whether or not the fail flag XFAIL1 has already been set. If the fail flag XFAIL1 has not been set, the process proceeds to step S22.

Next, in step S22, the difference between the guard position θmg detected by the guard position sensor 48 and the throttle opening θth detected by the throttle opening sensor 34 is equal to or greater than a predetermined value θb. It is determined whether or not. When a positive determination is made in step S22 (| θmg
−θth | ≧ θb), the counter Cb for counting the duration of the abnormal state is reset in step S23, and the throttle opening θth at this time is stored in the RAM 64 as the failing throttle opening θsave in step S24. Move to step S25.

If a negative determination is made in step S22 (| θmg−θth | <θb), the counter Cb is incremented by “+1” in step S26, and the routine goes to step S25. Then, in step S25, it is determined whether or not the counter Cb is less than a predetermined value KCb. When the determination is affirmative (Cb <KCb), the routine is terminated, and when the determination is negative ( Cb ≧ K
Cb) includes a fail flag XFAI in step S27.
L1 is set, and this routine ends.

Here, the actual throttle opening θth is
The guard position θmg should always be located on the closed side with a difference of a predetermined value or more. Therefore, when the state in which the difference between the guard position θmg and the throttle opening θth is continuously narrowed as described above, the DC motor 31 operates similarly to the first throttle control system abnormality determination routine described above. It is determined that the throttle opening control is not normally performed, and the fail flag XFAIL1 is set.

The fail flag XFAIL1
After the setting is made, since the affirmative determination is made in step S21 and the processing in step S24 is not executed, the throttle opening θth at the time when the fail determination is made is stored in the RAM 64.
Continues to be stored as the fail-time throttle opening θsave.

<Accelerator Linkage Mechanism Abnormality Determination Routine> On the other hand, when the accelerator linkage mechanism abnormality determination routine is called in step S30 of the fail determination routine, the CPU 6
2 moves to step S31 of FIG. First, in step S31, it is determined whether or not the internal combustion engine 1 is in normal operation. If cruise control or cold start is not being performed, it is determined that normal operation is in progress, and the process proceeds to step S32.

Next, at step S32, the guard position θmg detected by the guard position sensor 48 and the accelerator operation amount Ap detected by the accelerator position sensor 47
Then, it is determined whether or not the absolute value of the difference is smaller than a predetermined value θc set in advance. If an affirmative determination is made in step S32 (| θmg-Ap | <θc), the counter Cc for counting the duration of the abnormal state is reset in step S33, and the process proceeds to step S34.

If a negative determination is made in step S32 (| θmg−Ap | ≧ θc), the counter Cc is incremented by “+1” in step S35, and the routine goes to step S34. Then, in step S34, it is determined whether or not the counter Cc is smaller than a predetermined value KCc. When the determination is affirmative (Cc <KCc), this routine is terminated, and when the determination is negative ( Cc ≧
KCc) includes the accelerator interlocking mechanism 22 in step S36.
A fail flag XFAIL2 indicating the occurrence of the abnormality is set, and this routine is terminated.

Here, the guard position θmg when the cruise control or the cold start is not executed.
Is not changed in the opening direction by the diaphragm actuator 49 or the thermowax 50, and should always correspond to the accelerator operation amount Ap. Therefore, as described above, when a certain difference continuously occurs between the guard position θmg and the accelerator operation amount Ap, it is considered that excessive play has occurred in the accelerator interlocking mechanism 22 for some reason. be able to.

In such a case, even if an abnormality occurs in the throttle control system and the throttle valve 5 is opened / closed by the accelerator interlocking mechanism 22, an accurate throttle opening / closing operation corresponding to the accelerator operation amount Ap cannot be expected. . Therefore, at this time, the CPU 62 determines that the accelerator interlocking mechanism 22 has failed, and sets the fail flag XFAIL2.

When it is determined in step S31 that the internal combustion engine 1 is not operating normally, the guard position θmg has already been changed to the open side by the diaphragm actuator 49 or the thermowax 50, so it is determined whether there is any abnormality. This routine is immediately terminated because it is impossible.

<Spring Breakage Determination Routine> When the spring breakage determination routine is called in step S40 of the fail determination routine, the CPU 62 proceeds to step S4 of FIG.
Move to 1. First, the accelerator operation amount Ap detected by the accelerator position sensor 47 in this step S41.
It is determined whether or not the internal combustion engine 1 is in idle operation based on If the vehicle is idling, step S4
In step 2, a duty ratio signal is input from the PWM circuit 73,
Average value D of the duty ratio Duty per predetermined time
It is determined whether or not UtyAV is equal to or greater than a predetermined value Dutyd. If an affirmative determination is made in step S42 (DutyAv ≧ Dutyd), step S4
At 3, the counter Cd for counting the duration of the abnormal state is reset, and the routine goes to Step S44.

If a negative determination is made in step S42 (Dutyav <Dutyd), the counter Cd is incremented by "+1" in step S45, and the flow shifts to step S44. Then, in step S44, it is determined whether or not the counter Cd is less than a predetermined value KCd. When the determination is affirmative (Cd <KCd), the routine is terminated, and when the determination is negative, Cd ≧
In KCd), a fail flag XFAIL3 indicating the occurrence of spring breakage is set in step S46, and this routine ends.

Here, during the idling operation of the internal combustion engine 1, the throttle valve 5 is maintained at a substantially constant opening near the fully closed state by the ISC control, so that the total sum of the urging forces of the valve spring 25 and the return spring 32 is substantially equal. It has a constant value. Therefore, average value DutyAV of duty ratio Duty given to DC motor 31 to resist the urging force
Should also converge to an almost constant value, and the average value D
If the state in which the utyAV is lower than normal occurs continuously, it can be considered that one of the springs 25 and 32 is cut off and the throttle opening control may not be performed smoothly. . Therefore, at this time, the CPU 62 makes a failure determination of the spring breakage, and the failure flag XFAIL3 is set.

The reason why the cut-off of the springs 25 and 32 is determined based on the average value DutyAV is that the duty ratio Duty at this time fluctuates so as to maintain the idling speed, so that the duty ratio Duty itself is not changed. This is because an accurate judgment cannot be expected from the user. Step S41
When it is determined that the internal combustion engine 1 is not idling, the throttle valve 5 is opened as compared with the time of idling, so that the urging forces of the valve spring 25 and the return spring 32 do not reach the expected values, This routine is immediately terminated, assuming that it is impossible to determine the presence or absence of a cut.

<Valve Block Determination Routine> Further, when the valve block determination routine is called in step S50 of the fail determination routine, the CPU 62 shifts to step S51 in FIG. First, in this step S51, P
A duty ratio signal is input from the WM circuit 73, and the duty ratio Duty is set to a predetermined value Duty.
It is determined whether it is less than e. When an affirmative determination is made in step S51 (Duty <Duty), a counter C that counts the duration of the abnormal state in step S52.
e is reset, and the routine goes to Step S53.

If a negative determination is made in step S51 (Duty ≧ Duty), the counter Ce is incremented by “+1” in step S54, and the process proceeds to step S5.
Move to 3. Then, in step S53, the counter Ce
Is determined to be less than a predetermined value KCe, and if a positive determination is made (Ce <KCe), this routine is terminated, and if a negative determination is made (Ce ≧ KCe)
In e), a fail flag XFAIL4 indicating the occurrence of a valve block is set in step S55, and this routine ends.

Here, when a valve block occurs due to a foreign substance or the like that has entered into the intake passage 2, the DC motor 3
Even if the throttle valve 5 is driven to open and close at 1, the actual throttle opening θth does not reach the throttle opening command value θcmd. Therefore, the duty ratio Du at this time is
The ty is sharply increased by the control of the PID control circuit 72, and if this situation continues for a time that cannot be continued in the normal control state, it can be considered that the throttle valve 5 cannot be opened or closed. Therefore, at this time, the CPU 6
2, a fail determination of the valve block is made, and the fail flag XFAIL4 is set.

FIG. 12 is an explanatory view showing a map for determining a throttle opening command value during normal control in the throttle control device for an internal combustion engine according to one embodiment of the present invention.
FIG. 3 is an explanatory diagram showing a map for determining a throttle command voltage in a throttle control device for an internal combustion engine according to an embodiment of the present invention. FIG. 14 is a limp in a throttle control device for an internal combustion engine according to an embodiment of the present invention. FIG. 15 is a diagram illustrating a map for determining a throttle opening command value during home control, and FIG. 15 is a time chart when an abnormality occurs in a throttle control system in a throttle control device for an internal combustion engine according to one embodiment of the present invention. .

As described above, upon completion of each fail determination process, the CPU 62 returns to the throttle control routine of FIG.
It is determined whether or not IL1 to XFAIL4 have been cleared. In step S2, all fail flags XFAIL
1 to XFAIL4 are cleared (XFAIL
1 to 4 = 0) include all throttle functions of the internal combustion engine 1, for example, a throttle control system and an accelerator interlocking mechanism 22.
The normal throttle control is executed in the processing after step S3, assuming that the conditions are normal.

That is, the CPU 62 in FIG.
In accordance with a map stored in the ROM 63 in advance shown in FIG. 3, the accelerator operation amount Ap detected by the accelerator position sensor 47 and the engine speed Ne calculated based on the pulse signal from the crank angle sensor 15 are used for normal throttle control. The throttle opening command value θcmd is determined.

Next, the CPU 62 determines in step S4 that FIG.
According to the map previously stored in the ROM 63 shown in FIG.
The throttle command voltage Vcmd is determined from the throttle opening command value θcmd. Further, the throttle command voltage V
cmd in step S5 via D / A conversion circuit 67.
The output is output to the PID control circuit 72 of the C motor drive circuit 71, and this throttle control routine ends.

The throttle command voltage Vcmd output from the CPU 62 is compared with the output voltage Vth of the throttle opening sensor 34 by the PID control circuit 72, and a proportional / integral / differential operation is executed to reduce the deviation. ,
A control amount of the throttle valve 5 is calculated. Further, the control amount is converted into a duty ratio signal by the PWM circuit 73, and the DC voltage is converted by the driver 74 in accordance with the duty ratio signal.
The motor 31 is driven. Then, the processing of steps S1 to S5 by the CPU 62 and the drive control of the DC motor 31 by the DC motor drive circuit 71 are repeatedly executed, and the actual throttle opening θth is adjusted to the throttle opening command value θcd. You.

On the other hand, if any one of the fail flags XFAIL1 to XFAIL4 is set in step S2 (XFAIL1 to 4 ≠ 0), step S6 is executed.
Outputs a control signal to the lamp drive circuit 68 to turn on the warning lamp 69. Next, the fail flags XFAIL1 to XFAI set in step S7 are set.
The type of L4 is determined, and when the fail flag XFAIL3 is set, the valve spring 25 or the return spring 3
Assuming that 2 has been cut off, the process proceeds to step S3, and normal throttle control is executed as in the case where all the throttle functions are normal.

That is, even if any one of the valve spring 25 and the return spring 32 breaks, the running of the vehicle is not immediately hindered. Therefore, the warning lamp 69 is lit to prompt the driver to perform inspection and repair. It is. If it is determined in step S7 that the fail flag XFAIL2 has been set, it is considered that excessive play has occurred in the accelerator interlocking mechanism 22, and the process proceeds to step S8 to execute so-called limp home control.

That is, the CPU 62 in FIG.
The throttle opening command value θcmd at the time of the limp home control is determined from the accelerator operation amount Ap detected by the accelerator position sensor 47 in accordance with a map previously stored in the ROM 63 shown in FIG. As is clear from the comparison with FIG. 12, for the same accelerator operation amount Ap, a smaller throttle opening command value θcmd is set in this limp home control. Then, in step S4, the throttle command voltage Vc is calculated from the throttle opening command value θcmd.
md is determined, and the throttle command voltage Vcmd is output to the PID control circuit 72 in step S5.

That is, when the normal throttle control is switched to the limp home control, the throttle opening command value θcmd is greatly reduced, and the throttle valve 5 is controlled in the closing direction. Therefore, the engine torque decreases irrespective of the accelerator operation, and the driver can immediately detect the abnormality based on the decrease in the torque without visually recognizing the warning lamp 69. Further, even after switching to the limp home control, the throttle opening control is performed, so that the vehicle can continue to run, and the throttle opening is suppressed, so that the driver is encouraged to drive carefully. .

In step S7, the fail flag XF
When it is determined that AIL1 or the fail flag XFAIL4 is set, it is determined that an abnormality has occurred in the throttle control system or that a valve lock has occurred, and the process proceeds to step S9. Then, in step S9, the energization of the DC motor 31 is stopped, and this routine ends.

Here, when the valve lock occurs, the opening and closing of the throttle valve 5 is prevented, so that the throttle opening θth does not change even if the DC motor 31 is de-energized. On the other hand, when an abnormality occurs in the throttle control system, the throttle valve 5 can be opened and closed freely.
When the energization of the C motor 31 is stopped, the throttle valve 5 is rotated in the opening direction by the urging forces of the valve spring 25 and the return spring 32, and as shown in FIG.
h changes to the guard position θmg. Thereafter, the throttle valve 5 is mechanically opened and closed by the accelerator interlocking mechanism 22 in response to the accelerator operation.

In addition to the above-described interruption of the energization of the DC motor 31, when an abnormality occurs in the throttle control system and a valve lock occurs, a so-called fuel cut for stopping fuel injection to a specific cylinder of the internal combustion engine 1 is performed. And the cylinder is held at rest. Therefore, the fuel injection control process executed by the CPU 62 will be described next.

<< Fuel Injection Control Process >> FIG. 16 is a flowchart showing a fuel injection control routine executed by the CPU of the throttle control device for an internal combustion engine according to one embodiment of the present invention.
FIG. 17 is a flowchart showing a fuel cut flag setting routine executed by the CPU of the throttle control device for an internal combustion engine according to one embodiment of the present invention.

The fuel injection control routine of FIG. 16 is executed every 720 degrees of the crank angle of the internal combustion engine 1. First, C
The PU 62 determines the current internal combustion engine 1 from the intake air amount Qa detected by the air flow meter 4 and the engine speed Ne detected by the crank angle sensor 15 in step S101.
Calculates the required fuel injection amount and sets a pulse width corresponding to the fuel injection amount. Next, a fuel cut flag setting process is performed in step S102.

<Fuel Cut Flag Setting Routine> When the fuel cut flag setting routine is called, the CPU 62
Shifts to step S111 in FIG. Now, if no abnormality in the throttle control system or valve lock occurs, the fail flag XFAIL1 and the fail flag XFAIL4
It is assumed that both have been cleared.

In step S111, the CPU 62 determines whether or not the fail flag XFAIL1 or XFAIL4, which has been cleared so far, has been set. Which fail flag XFAIL1, XFA
Since IL4 has not been set, the process proceeds to step S112, and any one of the fail flags XFAIL1 and XFAIL1
It is determined whether FAIL4 is currently set.
As in the case of step S111, since none of the fail flags XFAIL1 and XFAIL4 have been set, this routine ends. In other words, no measures are taken in this routine unless an abnormality of the throttle control system or valve lock occurs.

If a fail determination is made due to an abnormality in the throttle control system or the occurrence of a valve lock, and one of the fail flags XFAIL1 and XFAIL4 is set, the flow shifts from step S111 to step S113 to execute the fuel cut processing. Fuel cut flag X indicating execution of
Set FC. Next, the process proceeds to step S114 via step S112, in which it is determined whether or not the accelerator operation amount Ap is 0, and the accelerator operation amount Ap is not 0 (Ap ≠).
0), that is, when the accelerator operation is being performed,
This routine ends. Thereafter, as long as the accelerator operation is performed, the processing of step S111, step S112, and step S114 is repeatedly executed, and step S1 is performed.
When the accelerator operation amount Ap becomes 0 at 14 (Ap = 0),
In step S115, the fuel cut flag XFC is cleared.

Therefore, as shown in FIG. 15, the fuel cut flag XFC is maintained in the set state from the time when the fail determination is made to the time when the accelerator operation is stopped. When the fuel cut flag setting process is completed as described above, the CPU 62 returns to the fuel injection control routine of FIG. 16, and determines in step S103 whether the fuel cut flag XFC has been cleared.

When the fuel cut flag XFC is cleared (XFC = 0), that is, when no abnormality in the throttle control system or valve lock occurs, the process proceeds to step S104 to set the fuel cut cylinder number Nfc to zero. In step S105, the control signal of the pulse width set in step S101 for all the cylinders is output to the injector drive circuit 65. Therefore,
All injectors 7 are energized by the injector drive circuit 65 to inject fuel, and all cylinders of the internal combustion engine 1 operate. That is, in this case, normal fuel injection control is executed.

When the fuel cut flag XFC is set in step S103 (XFC = 1),
That is, when an abnormality of the throttle control system or a valve lock occurs, the process proceeds to step S106 to determine whether the fail flag XFAIL4 is set. When the fail flag XFAIL4 is set, it is considered that an abnormality exists in the valve block, and the number Nfc of fuel cut cylinders is set to 6 in step S107 (N
fc = 6), and the output of the control signal to the injector drive circuit 65 is stopped for all cylinders in step S105.

Therefore, the fuel injection of all the injectors 7 is stopped, and all the cylinders of the internal combustion engine 1 are stopped. Therefore, when this valve lock occurs, the engine torque is reliably suppressed to 0 by stopping the fuel injection, regardless of the opening degree of the locked throttle valve 5, and the running of the vehicle is stopped. If the fail flag XFAIL1 is set in step S106, it is determined that an abnormality is present in the throttle control system, and the process proceeds to step S108.
, The setting process of the fuel cut cylinder number Nfc is executed.

FIG. 18 is a flowchart showing a fuel cut cylinder number setting routine executed by the CPU of the throttle control device for an internal combustion engine according to one embodiment of the present invention. FIG. Explanatory diagram showing a map for determining the estimated torque in the control device,
FIG. 20 is an explanatory diagram showing a map for determining the number of fuel cut cylinders in the throttle control device for an internal combustion engine according to one embodiment of the present invention.

When the routine for setting the number of fuel cut cylinders Nfc is called, the CPU 62 proceeds to step S12 in FIG.
Move to 1. First, in this step S121, according to the map previously stored in the ROM 63 shown in FIG.
Fail throttle opening θs stored in M64
From the ave and the engine speed Ne detected by the crank angle sensor 15, a fail time estimated torque Tfa, which is the engine torque of the internal combustion engine 1 at the time of fail determination, is determined. The characteristics of the map shown in FIG.
For example, when the engine speed Ne is low, the upper limit of the actual engine torque with respect to the accelerator operation amount Ap is low. Therefore, the fail-time estimated torque Tfa is also suppressed to a small value. I have.

Next, at step S122, the above-described FIG.
9, the accelerator operation amount Ap detected by the accelerator position sensor 47 and the crank angle sensor 1
5, the post-failure estimated torque Ta, which is the current engine torque after the failure determination, based on the engine speed Ne detected at 5.
Determine p. Further, in step S123, the estimated torque at failure Tfa is subtracted from the estimated torque after failure Tap to calculate a torque increase ΔT (ΔT = Tap−Tfa). This torque increase ΔT is determined by the throttle opening θt.
h is the guard position θm by stopping the energization of the DC motor 31
5 shows an increase in the engine torque when the opening direction changes to g.

Here, as shown in the map of FIG. 12, the throttle opening command value θcmd is close to the accelerator operation amount Ap in the region near the fully closed state and the fully opened state, and is compared with the accelerator operation amount Ap in the intermediate region. Set to a lower value, and
Particularly, in the intermediate region, the lower the engine speed Ne, the lower the value is set. Therefore, when the throttle opening θth changes to the guard position θmg at the time of the failure determination, the change amount is the accelerator operation amount Ap or the engine speed Ne at that time.
, And the torque increase ΔT also changes accordingly. Therefore, by the processing of steps S121 to S123, the engine torques before and after the failure determination (failed estimated torque Tfa, post-failed estimated torque Tap).
Are estimated, and the torque increase ΔT is obtained.

Then, in step S124, the CPU 62 determines the number Nfc of fuel cut cylinders from the torque increase ΔT according to the map previously stored in the ROM 63 shown in FIG. 20, and terminates this routine. As is clear from the figure, the number of fuel cut cylinders Nfc at this time is set to a larger value as the torque increase ΔT increases.

Thereafter, the CPU 62 returns to the fuel injection control routine of FIG. 16, and outputs a control signal to the injector drive circuit 65 for the cylinder corresponding to the fuel cut cylinder number Nfc in step S105. As a result, the number of injectors 7 corresponding to the number of fuel cut cylinders Nfc is energized by the injector drive circuit 65 to inject fuel, and those cylinders operate.

Therefore, when a failure determination is made due to an abnormality in the throttle control system, and the throttle opening θth changes to the guard position θmg in the opening direction as shown in FIG. 15, the fuel is increased based on the torque increase ΔT. The number of cut cylinders Nfc is set. Then, a specific cylinder is cut off in fuel in accordance with the number of fuel cut cylinders Nfc and stopped, and the engine torque is reduced by an amount substantially equal to the torque increase ΔT. That is, fluctuations in the engine torque before and after the failure determination are prevented, and the vehicle acceleration G after the failure is maintained at a very small value similar to that before the failure determination. Therefore, an increase in the engine torque contrary to the driver's intention is reliably suppressed, and the operation can be continued without adjusting the accelerator operation amount Ap.

If all cylinders continue to operate without fuel cut, the engine torque increases together with the throttle opening θth, so that the vehicle acceleration G is indicated by a two-dot chain line against the driver's intention. Increase as shown. Therefore, the driver at this time needs to suppress the depression of the accelerator pedal 44. Then, as described above, after the throttle opening θth has changed to the guard position θmg, the throttle valve 5 is opened / closed mechanically interlocking with the accelerator operation via the accelerator interlocking mechanism 22. Therefore, a reliable throttle operation can be continuously performed without being affected by the abnormality of the throttle control system at all.

When the driver's accelerator operation amount Ap gradually decreases to stop the vehicle after the failure determination, the estimated post-failure torque Tap determined in step S122 in FIG. 18 decreases, and the torque increases in step S123. Along with the minute ΔT, the number Nfc of fuel cut cylinders in step S124 gradually decreases. Then, as shown in FIG. 15, when the accelerator operation amount Ap decreases to the fail-time throttle opening θsave, the number of fuel cut cylinders N
fc returns to 0, and when the accelerator operation amount Ap further decreases to 0, the fuel cut flag XFC is cleared in step S115 in FIG. Therefore, when the running of the vehicle is restarted by the accelerator operation, the fuel cut cylinder number Nfc is held at 0 in step S104 in FIG. 16, and normal fuel injection control for performing fuel injection to all cylinders is executed.

That is, the purpose of the throttle control device of this embodiment is to suppress an increase in engine torque when the throttle opening θth is opened to the guard position θmg by fail determination. Although the throttle valve tends to open slightly with respect to the operation amount Ap, no action is taken as it does not hinder traveling. In addition, as will be described later, the cylinders for which fuel is cut in accordance with the number of fuel cut cylinders Nfc are determined in consideration of the rotational balance of the internal combustion engine 1, but are compared with those in the normal case where fuel injection is performed for all cylinders. Then, it is inevitable that the vibration of the internal combustion engine 1 increases. Therefore, by holding the fuel cut cylinder number Nfc at 0 when the accelerator operation amount Ap becomes 0 as described above,
After the failure determination, an increase in vibration due to cylinder deactivation is prevented.

Incidentally, for reference, the aforementioned step S124
An example of the selection of the fuel cut cylinder according to the number Nfc of fuel cut cylinders executed in the above will be described. FIG. 21 is an explanatory diagram showing a map for determining a cylinder to stop fuel injection from the number of fuel cut cylinders in the throttle control device for an internal combustion engine according to one embodiment of the present invention.

As described above, the internal combustion engine 1 of this embodiment has a V
The ignition order is set in the order of cylinder numbers, that is, in the order of # 1 to # 6. However, the fuel cut cylinder in FIG. 21 is not the cylinder number, but the cylinder to which fuel is injected first after the failure determination is set to “1”. Therefore, for example, when the fuel injection to the # 4 cylinder is completed, a fail determination is made, and when the number Nfc of fuel cut cylinders is set to 3, the fuel cut cylinders are "1,""3," and "5." Is set, but since the cylinder to be injected next is # 5,
The fuel of cylinders # 5, # 1, and # 3 is cut off. Needless to say, the fuel cut cylinder shown in the figure is determined in consideration of the rotational balance of the internal combustion engine 1.

In this embodiment, the accelerator operation amount Ap,
Although the torque increase ΔT is estimated from the throttle opening θth and the engine speed Ne, it may be estimated from the intake air amount Qa or the intake pipe pressure Pm instead of these parameters. In other words, the estimated torque at failure Tfa = the intake air amount Qa or the intake pipe pressure Pm when a failure occurs, the estimated torque after failure Tap = the intake air amount Qa after the failure determination
Alternatively, the torque increase ΔT may be estimated as the intake pipe pressure Pm.

Further, in the above-described embodiment, in the first throttle control system abnormality determination routine, the control estimated throttle opening θ
The state where the difference between the guard position θmg and the throttle opening θth is narrowed when a certain degree of difference continuously occurs between the cmdo and the actual throttle opening θth, and in the second throttle control system abnormality determination routine. When the occurrence of continually occurred, the failure judgment of the throttle control system was performed. However, the abnormality of the throttle control system in the present invention is not limited to this, and
1 cannot be executed, and includes all situations where a mechanical throttle operation by the accelerator interlocking mechanism 22 is required. Therefore, for example, when a mechanical abnormality occurs in the motor control mechanism 22, the failure determination of the throttle control system may be performed.

Further, in the above embodiment, the normal throttle control for controlling the running of the vehicle is performed by the DC motor 31. However, the present invention is not limited to this. The content of the throttle control is not limited as long as the throttle valve 5 is electrically opened and closed.

Therefore, for example, Japanese Utility Model Application Laid-Open No. 2-3724
As disclosed in Japanese Patent Application Publication No. 5 (1993) No. 5, the present invention is applied to a traction control (hereinafter simply referred to as "TRC").
) Can be applied to throttle control.

To explain an example of the publication, this throttle control device is provided with a pair of throttle valves, and one of the main throttle valves is opened / closed in a mechanically interlocked manner with an accelerator operation to drive the vehicle. Plays a controlling role. Further, the other auxiliary throttle valve is controlled to be closed by the TRC when a slip occurs in the drive wheels of the vehicle, and serves to reduce the engine torque and suppress the slip.

Here, as described in the official gazette, T
If an abnormality occurs in the throttle control system during RC, the auxiliary throttle valve controlled to the closed side is kept fully open so as to stop TRC immediately. Therefore, the intake air amount of the internal combustion engine increases to a value corresponding to the opening of the main throttle valve, and the engine torque increases. Therefore, as in the above embodiment, if a specific cylinder is deactivated according to the increase in the engine torque, it is possible to suppress a sudden increase in the torque at this time.

In the throttle control device shown in FIG. 2, during cruise control traveling, the guard lever 45 is turned in the opening direction by the diaphragm actuator 49, and the throttle is operated by the DC motor 31 even if the accelerator is not operated. The rotation of the valve 5 is controlled. Further, the throttle valve opening during and after warm-up during idling is controlled by the thermowax 50 and the operating rod 50a.

FIG. 2 shows another embodiment in which an electromagnetic clutch or the like is provided in place of the diaphragm actuator 49, the thermowax 50, and the operating rod 50a as described above, and cruise control and idling control are normally performed.
It is shown in FIG. FIG. 22 schematically shows the configuration of a throttle control device provided with an electromagnetic clutch, as shown in FIG. 3, showing the operation principle around the throttle valve. In this figure, the upper part is the opening direction of the throttle valve 5, and the lower part is the closing direction.

In this embodiment shown in FIG. 22, the accelerator opening sensor 47 of the embodiment shown in FIG. 2 is not attached, and the accelerator operation amount is substituted by the guard position sensor 48. Further, the throttle opening sensor 34 is attached to the driven gear 28. Hereinafter, the operation of the throttle control device will be described. Normally, the power supply to the clutch coil 80a of the electromagnetic clutch 80 is cut off. When the driver operates the accelerator pedal 44, a signal θmg corresponding to the accelerator operation amount is output from the guard position sensor 48, and the DC motor 31 is driven based on this signal. Then, the driven gear 28 rotates to the open side, and the throttle valve 5 opens accordingly.

On the other hand, during cruise control, power is supplied to the clutch coil 80a of the electromagnetic clutch 80, and the driven gear 28 and the throttle shaft 23 are directly connected. This allows
The opening and closing of the throttle valve 5 is controlled by the DC motor 31. In the embodiment shown in FIG.
A guard stopper 90 for restricting further rotation on the closing side is provided on the throttle valve 5 closing direction side. The throttle valve opening corresponding to the guard stopper 90 is a fully closed position stopper 26 indicating the fully closed position of the throttle valve 5.
The opening degree is set to be slightly larger than the opening degree.
Thus, when the throttle valve 5 is in the fully closed position and the guard lever 45 contacts the guard stopper 90, a predetermined gap is formed between the guard lever 45 and the stopper lever 24.

Thus, during idling, the throttle valve 5 can be controlled by the DC motor 31 in the opening range corresponding to the position of the guard stopper 90 from the fully closed position. Even when the load of the internal combustion engine 1 varies, the idle speed can be kept constant by controlling the DC motor 14. further,
In this embodiment, a bypass passage 100 that bypasses the throttle valve 5 is provided, and an air valve 110 that controls opening and closing of the passage 100 is provided. This air valve 1
Numeral 10 is opened so that the amount of bypass air is increased when the engine is cold, and closed after the warm-up is completed to reduce the amount of bypass air. After the warm-up, the DC motor 31 controls the throttle valve 5 within the predetermined gap.

Here, the bypass passage 100 as described above is used.
In the throttle control device which is not provided and is controlled in idle speed by the throttle valve 5 even in a cold state, the throttle valve 5 corresponds to a desired idle speed even after warm-up due to failure of the DC motor 31 and the control device 61 and the like. There is a possibility that a malfunction that the engine speed is abnormally increased due to the open state at the opening degree or more may occur. However, by providing the bypass passage 100 as described above,
Such a defect does not occur.

In this throttle control device, the various failure determinations described in the embodiment of FIG.
When it is determined that an abnormality in the throttle control system or a valve lock has occurred, fail-safe processing corresponding to the abnormality is performed in the same manner as in the embodiment of FIG. 2, and cylinder number control and estimated torque calculation are performed. However, in the electromagnetic clutch 80 shown in FIG. 22, when the clutch coil 80a is switched from the energized state to the non-energized state, the clutch is not reliably released, and the direct connection between the throttle valve 5 and the driven gear 42 is not released. Clutch lock may occur.

Therefore, when the above-described clutch lock occurs, it is necessary to reliably detect this abnormality. Hereinafter, the clutch lock detection processing will be described.

The clutch lock detection process is performed when the cruise control is released. Cruise control is performed when the brake is depressed, that is, as shown in FIG.
As shown in FIG. 7, when the brake signal is turned on, the clutch coil 80 is disconnected so that the electromagnetic clutch 80 releases the connection between the driven gear 28 and the throttle valve 5.
The clutch signal to a is turned off (FIG. 23B).

Here, when the brake is depressed, the amount of depression of the accelerator can be considered to be almost zero, so that the guard lever 45, the stopper lever 24, the throttle shaft 23, and the like rotate in the closing direction by the urging force of the spring 46. try to. Therefore, the output value θmg of the guard position sensor 48 approaches the value corresponding to the position of the guard stopper 90, as shown by the solid line in FIG. Therefore, when the cruise control is released, the driven gear 28 is maintained at the position at that time for a predetermined time (KC1) as shown in FIG.
The throttle opening command value θ is supplied to the DC motor 31 as indicated by the broken line in FIG.
cmd is output, and after a predetermined time, the driven gear 28 is also brought to the position of the fully closed position stopper 26. Then, if the clutch is securely disengaged, the driven gear 28 is brought to the position of the fully closed position stopper 26 after the predetermined time, and the driven gear 28
Θth, which is the output value of the throttle opening sensor 34 attached to the sensor, is as shown by the dashed line in FIG.

On the other hand, if the clutch is locked, the guard lever 4 is not released even after the cruise control is released.
5. The stopper lever 24, the throttle shaft 23 and the like are held at the same position. Then, after the predetermined time,
When the driven gear 28 is rotated in the closing direction, the driven gear 28 is rotated in accordance with the rotation. Therefore, θmg coincides with θcmd as shown by a solid line in FIG.

Accordingly, after the cruise control is released, the driven gear 28 is held by the DC motor 31 for a predetermined time, and if θmg and θcmd at this time are detected, it can be determined whether or not clutch lock has occurred. Hereinafter, FIG.
The clutch lock detection process at the time of releasing the cruise control will be described with reference to the flowchart shown in FIG. Note that this clutch lock detection processing is performed in the embodiment of FIG.
It is incorporated in one of a plurality of fail determination processes in the fail determination process routine of FIG. 5 executed in step S1 of the throttle control routine of FIG.

When the clutch lock detection routine is called in the fail determination routine shown in FIG.
The process moves to step S201 in FIG. Step S20
In step 1, it is determined whether a clutch lock determination flag XFCLT indicating the occurrence of clutch lock has been set. When the determination flag XFCLT is set, the present processing ends.

On the other hand, if the determination flag XFCLT is not set in step S201, the process proceeds to step S202. Thereafter, in steps S202 to S206, a delay of a predetermined time KC1 from the release of the cruise control is performed.
A process for closing θcmd is performed. That is, in step S202, the clutch signal shifts from ON to OFF, and it is determined whether the cruise control has been released. If it is determined that the clutch signal has shifted from ON to OFF, the counter CCLT is set to zero in step S203. If not, the counter CCLT is incremented (CCL) in step S204.
T = CCLT + 1). Thus, the counter CCLT is counted up from the time when the clutch signal is turned off from ON.

Then, in a step S205, it is determined whether or not the count value of the counter CCLT is smaller than a predetermined time KC1. If the counter value CCLT is smaller than KC1, the process proceeds to step S206; otherwise, the process ends. Then, when the counter value CCLT is K
If it is smaller than C1, that is, if the predetermined time KC1 has not been reached since the release of the cruise control, step S2
At 06, the current θcmdi is made the same as the previous θcmdi-1. Then, the process proceeds to step S208, and it is determined whether or not θmg is smaller than θcmd. θmg is θc
If it is smaller than md, proceed to step S210; otherwise, proceed to step S209. Then, in step S209, the counter CCLTF is incremented (CCLTF = CCLTF + 1), and in step S2
Proceed to 11. On the other hand, in step S210, the counter C
CLTF is set to zero, and the process proceeds to step S211.
As a result, clutch lock abnormality occurs, and θmg and θ
It is possible to detect how long the state where the value of cmd is the same is continued.

Then, in a step S211, it is determined whether or not the value of the counter CCLTF is smaller than a predetermined time KCF. If it is determined that the value of the counter CCLTF is smaller than the predetermined time KCF, the present process is terminated as it is. Otherwise, the clutch lock determination flag XFCLT is set in step S212, and the present process is terminated. Then, this process is completed, and the process returns to the throttle control routine of FIG. At this time, the clutch lock determination flag X
If FCLT is set, the process proceeds to steps S2, S6, S7, and S9 of the throttle control routine in FIG. 4 to turn on the warning lamp and stop energizing the DC motor 31. On the other hand, if the clutch lock determination flag XFCLT is not set, steps S2, S3, S4 of the throttle control routine of FIG.
Proceeding to S5, the throttle opening command value θcmd during normal throttle control is set, and θcmd is set to Vcm.
d and output this Vcmd.

Thus, the clutch lock of the electromagnetic clutch 80 can be determined at the time of releasing the cruise control. Further, the clutch lock of the electromagnetic clutch 80 may be detected not at the time of releasing the cruise control as described above but at the time of starting the engine, that is, when an ignition switch (hereinafter referred to as IGSW) is turned on.

That is, as shown in FIG.
When the GSW is turned on, FIG.
As shown in (c), the output value θcm to the DC motor 31 is
d is a value (KMG) at which the throttle valve 5 is opened by a predetermined opening (for example, + 5 °) from the position of the guard stopper 90, and this value is held for a predetermined time (KC2). Then, during this time, θmg and θcmd are compared. Here, if the clutch is not locked, since the throttle valve 5 is at the position of the guard stopper 90, θmg <θcmd as shown in FIG.
On the other hand, if clutch lock has occurred, FIG.
Θmg = θcmd as shown in FIG. And θm
If the state of g = θcmd continues for a predetermined time (KCF), it is determined that the lock is established.

FIG. 26 shows the clutch lock detecting process according to this process. Note that this processing is the same as that shown in FIG.
Are substantially the same as those shown in FIG. 24, and the same portions are denoted by the same reference numerals as in FIG. 24, and description thereof is omitted. Step S2
At 22, it is determined whether or not the IGSW has changed from OFF to ON. If it is determined that the IGSW has changed from OFF to ON, the process proceeds to step S203.
Proceed to. As a result, the counter is counted up from the point when the IWSW is turned on.

In step S225, it is determined whether the count value of the counter CCLT is smaller than a predetermined time KC2. If the counter value CCLT is smaller than KC1, the process proceeds to step S226; otherwise, the process ends. Then, in step S226, θ
cmd is retained as the above KMG. Next, step S
At 208, by comparing θmg and θcmd (= KMG), it can be detected whether or not clutch lock has occurred.

The clutch lock detecting process shown in FIG. 26 is normally executed at the start of deceleration fuel cut which is executed when the accelerator pedal is fully closed and the engine speed is equal to or higher than a predetermined speed. Good. This is because during the deceleration fuel cut, no matter how the throttle valve 5 is driven, it does not affect the behavior of the engine. The clutch lock detection process at the time of deceleration fuel cut is described below with reference to FIG.
Indicated by This processing is almost the same as the processing in FIG. 26 described above, and the different point is step S232, so that the description of the other processing is omitted.

In the step S232, it is determined whether or not the deceleration fuel cut flag XDFC has been set from 0 to 1. Normally, this flag XDFC indicates that the accelerator pedal is in the fully closed position and the engine speed is a predetermined speed (for example,
1500 rpm), it is set to be set. If it is determined that XDFC has been set, the process proceeds to step S203. Otherwise, the counter CCLT is incremented (CCLT = CCLT +
1) Yes. As a result, the count is increased from the time when the deceleration fuel cut is executed. Step S22
At 6, the θcmd is held by the KMG. Then, in step S208, by comparing θmg and θcmd, it can be detected whether or not clutch lock has occurred.

Next, as another embodiment, the number Nfc of fuel cut cylinders may be set based on the vehicle speed or the engine speed. A schematic configuration diagram of this embodiment is shown in FIG.
Shown in FIG. 28 is obtained by adding a vehicle speed sensor 121 and a shift position sensor 122 to the schematic configuration diagram shown in FIG. Other configurations are the same as those in FIG.

In such a configuration, a flowchart executed by the CPU 62 instead of FIG. 16 is shown in FIG. In this flowchart, when the IGSW is turned on, the fail flag XFAIL1 is set to "0" as an initialization process.
And Further, this flowchart is executed every 720 degrees of the crank angle of the internal combustion engine 1.

When this processing is executed, step S30
In step 1, the fuel injection amount required by the internal combustion engine 1 is calculated from the intake air amount Qa detected by the air flow meter 4 and the engine speed Ne detected by the crank angle sensor 15, and the fuel injection amount is calculated. Set the pulse width corresponding to the injection amount. Next, in step S302, the fail flag XF
It is determined whether AIL1 is "1". If it is not "1", the flow proceeds to step S303, the fuel cut cylinder number Nfc is set to "0", and the flow proceeds to step S307.

In step S302, if the fail flag XFAIL1 is "1", the flow advances to step S304 to determine whether the driving force of the engine is currently being transmitted to the driving wheels. That is, in the case of an automatic transmission (AT) vehicle, it is determined from the detection signal of the shift position sensor 122 whether the gear shift position is the drive or reverse position. In the case of a manual transmission (MT) vehicle, it is determined whether the gears are connected and the clutch is engaged. Here, when the driving force is transmitted, step S306
Proceed to. If not, the process proceeds to step S305.

In step S306, the number of fuel cut cylinders Nfc corresponding to the vehicle speed detected by the vehicle speed sensor 121 is set from the map shown in FIG. That is, the lower the vehicle speed, the greater the number of fuel cut cylinders Nfc.
In step S305, the number of fuel cut cylinders Nfc is set from the map shown in FIG. That is, the number Nfc of fuel cut cylinders increases as the engine speed increases. When the fuel cut cylinder number Nfc is set in steps S305 and S306, a control signal is output to the injector drive circuit 65 for the cylinder corresponding to the fuel cut cylinder number Nfc in step S301 in step S307. As a result, the number of injectors 7 corresponding to the number of fuel cut cylinders Nfc is energized by the injector drive circuit 65 to inject fuel, and those cylinders operate.

By executing the above processing, when the driving force is transmitted, the number of fuel cut cylinders Nfc is set according to the vehicle speed. Specifically, the number Nfc of fuel cut cylinders increases as the vehicle speed decreases. As a result, when the vehicle is stationary, the number of fuel cut cylinders Nfc is increased to suppress the torque and prevent the vehicle from jumping out. Further, as the vehicle speed increases, the number of fuel cut cylinders Nf
Since c is set to be small, deterioration of drivability is also prevented.

When the driving force is not transmitted,
The fuel cut cylinder number Nfc is set according to the engine speed. More specifically, the number Nfc of fuel cut cylinders is set to increase as the engine speed increases.
Thus, it is possible to prevent an increase in the engine speed when the driving force of the engine is not transmitted to the wheels when the gear shift position is in a neutral state or the like. Excessive rotation of the engine at the time of neutral causes anxiety of the driving vehicle, but this can be prevented.

The above processing is continued until the IGSW is turned off once a failure is detected. And then I
Since the fail flag XFAIL1 is reset to "0" when the GSW is turned on, the fuel injection processing in the normal state is returned if the state is returned to the normal state, and the fail flag XFAIL1 is set to "2" again if the abnormal state is continued. Since it becomes 1 ", a fuel cut is executed, and a fuel injection process accompanying the fuel cut is executed.

In the above embodiment, FIGS.
A hysteresis characteristic may be given to the fuel cut cylinder number Nfc switching condition in the map shown in FIG.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a throttle control device for an internal combustion engine which is an example of an embodiment of the present invention.

FIG. 2 is a perspective view showing the vicinity of a throttle valve to which a throttle control device for an internal combustion engine according to one embodiment of the present invention is applied;

FIG. 3 is an explanatory diagram schematically showing an operation principle around a throttle valve to which a throttle control device for an internal combustion engine according to an embodiment of the present invention is applied.

FIG. 4 is a flowchart showing a throttle control routine executed by a CPU of a throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 5 is a flowchart illustrating a fail determination routine executed by the CPU of the throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 6 is a flowchart showing a first throttle control system abnormality determination routine executed by a CPU of the internal combustion engine throttle control device according to one embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a control delay of an actual throttle opening with respect to a throttle opening command value of a throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 8 is a flowchart showing a second throttle control system abnormality determination routine executed by the CPU of the internal combustion engine throttle control device according to one embodiment of the present invention.

FIG. 9 is a flowchart illustrating an accelerator interlocking mechanism abnormality determination routine executed by a CPU of a throttle control device for an internal combustion engine according to an embodiment of the present invention.

FIG. 10 is a flowchart illustrating a spring breakage determination routine executed by a CPU of a throttle control device for an internal combustion engine according to an embodiment of the present invention.

FIG. 11 is a flowchart illustrating a valve block determination routine executed by a CPU of a throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 12 is an explanatory diagram showing a map for determining a throttle opening command value during normal control in a throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 13 is an explanatory diagram showing a map for determining a throttle command voltage in a throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a map for determining a throttle opening command value at the time of limp home control in a throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 15 is a time chart when an abnormality occurs in a throttle control system in a throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 16 is a flowchart showing a fuel injection control routine executed by a CPU of a throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 17 is a flowchart showing a fuel cut flag setting routine executed by a CPU of a throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 18 is a flowchart showing a fuel cut cylinder number setting routine executed by a CPU of a throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 19 is an explanatory diagram showing a map for determining an estimated torque in the throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 20 is an explanatory diagram showing a map for determining the number of fuel cut cylinders in the internal combustion engine throttle control device according to one embodiment of the present invention.

FIG. 21 is an explanatory diagram showing a map for determining a cylinder for which fuel injection is to be stopped based on the number of fuel cut cylinders in the throttle control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 22 is an explanatory view schematically showing an operation principle around a throttle valve to which a throttle control device for an internal combustion engine according to another embodiment of the present invention is applied.

FIG. 23 is a time chart of each signal when the cruise control is released.

FIG. 24 is a flowchart showing a clutch lock detection routine.

FIG. 25 is a time chart of each signal when an ignition switch is ON.

FIG. 26 is a flowchart illustrating a clutch lock detection routine.

FIG. 27 is a flowchart illustrating a clutch lock detection routine.

FIG. 28 is a schematic configuration diagram showing a throttle control device for an internal combustion engine according to another embodiment.

FIG. 29 is a flowchart showing processing executed by a CPU in another embodiment.

FIG. 30 is an explanatory diagram showing a map for determining the number of fuel cut cylinders from a vehicle speed in a throttle control device for an internal combustion engine in another embodiment.

FIG. 31 is an explanatory diagram showing a map for determining a fuel cut cylinder number from an engine speed in a throttle control device for an internal combustion engine in another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal combustion engine 5 Throttle valve 7 Injector 22 Accelerator interlocking mechanism 31 DC motor 62 CPU 65 Injector drive circuit 121 Vehicle speed sensor 122 Shift position sensor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) F02D 17/02 F02D 17/02 R (72) Inventor Hitoshi Tasaka 1-1-1 Showa-cho, Kariya-shi, Aichi Pref. (72) Inventor Mitsuo Hara 1-1-1, Showa-cho, Kariya-shi, Aichi Pref.

Claims (5)

[Claims] 1. A throttle control means for setting a throttle opening command value of a throttle valve of an internal combustion engine based on an accelerator operation amount, and controlling the throttle valve by a motor based on the throttle opening command value; A throttle for an internal combustion engine, comprising: a plurality of abnormality detection means for detecting abnormality of the control means; and fail-safe means for performing fail-safe processing according to the degree of abnormality detected by the plurality of abnormality detection means. Control device. A plurality of abnormality detecting means for detecting an abnormality relating to a throttle valve opening; an accelerator abnormality detecting means relating to an accelerator operation amount; and a lock state of the throttle valve. The fail-safe means comprises: first fail-safe means for stopping the motor when an abnormality is detected by the throttle-system abnormality detection means or the valve-block detection means; and A second fail-safe means for setting a throttle opening command value set based on the accelerator operation amount when an abnormality is detected by the accelerator system abnormality detecting means to be smaller than a normal state. The throttle control device for an internal combustion engine according to claim 1, wherein 3. The throttle control device for an internal combustion engine according to claim 2, wherein said first fail-safe means further comprises means for reducing the number of cylinders to which fuel is supplied. 4. The throttle control of an internal combustion engine according to claim 3, wherein said first fail-safe means sets the number of cylinders to which no fuel is supplied based on a torque estimation value based on an operating state. apparatus. 5. The throttle valve includes a spring that urges the throttle valve in a predetermined direction, the plurality of abnormality detection units further include a spring breakage detection unit that detects a breakage of the spring, 5. The throttle control device for an internal combustion engine according to claim 2, wherein the fail-safe means executes a normal throttle control when a spring breakage is detected by the spring breakage detecting unit.