JPH0763102A - Throttle control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To restrain any increase in an engine torque in the case of a change to the open side of a throttle opening in accordance with the generation of abnormality and attempt the requlation of an acceleration operation feeling by stopping a specific cylinder in accordance with the increase amount of the engine torque in the case of the generation of abnormality in a throttle control system. CONSTITUTION:The opening of a throttle value M2 in an internal combustion engine M1 is driven-changed by a means M3 and also by the means M4 interlocking with an acceleration pedal on the more opening side than the case of the means M3. In the case of the generation of abnormality of a throttle control system, only one side means M4 is operated. In this case, respective engine torques are estimated by a means M5 respectively at the time of abnormality generation in the throttle control system and after the opening side change of the throttle opening in accordance with the generation of abnormality. Meanwhile, the increased amount of the engine torque befweed those before/after the generation of abnormality is calculated based on the estimated engine torque and the number of stopped cylinder is set by a means M6 in accordance with this increased amount. A specific cylinder is stopped by a means M7 in accordance with the number of set stopped cylinder in the case of the abnormality generation in the throttle control system.

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, and more particularly, to electrically controlling the opening of the throttle valve by a motor or the like and, when an abnormality occurs in the control system of the throttle valve, The present invention relates to a throttle control device for an internal combustion engine that suppresses a rapid increase in engine torque due to an opening operation.

[0002]

2. Description of the Related Art In recent years, many throttle control devices have been proposed which electrically control the opening of a throttle valve of an internal combustion engine by a motor or the like, and the characteristic of the throttle opening with respect to the accelerator operation amount can be arbitrarily set. Therefore, there is an advantage that it is possible to appropriately respond to 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 that 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 that And in such a case, the engine torque suddenly increases against the driver's intention,
There was a problem that it caused discomfort.

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.
The thing described in 59346 can be mentioned.
The former throttle controller has an engine speed of 2000rp
When an abnormality occurs in the throttle control system when m is exceeded, fuel cut is intermittently performed for each cylinder,
The engine speed is limited to 2000 rpm or less, thus preventing a rapid increase in engine torque.

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 the four cylinders of the internal combustion engine 3 cylinders are stopped by the fuel cut to suppress the engine torque, and when the accelerator operation is performed, the 1 cylinder during the fuel cut is recovered to secure the engine torque to the extent that the vehicle can continue running. is doing.

That is, in the above two types of throttle control devices, a sudden increase in engine torque is suppressed by fuel cut when an abnormality occurs in the throttle control system. However, the fuel cut is executed by an electric fuel control system similar to the throttle control system, so there is a possibility that the fuel cut will not be executed due to the influence of the abnormality in the throttle control system, and the reliability as a countermeasure against the abnormality occurs. The sex was not enough.

[0006] Therefore, as a throttle control device for an internal combustion engine, which is provided with a more reliable measure against an abnormality in the throttle control system, for example, the one shown in Fig. 23 can be cited. FIG. 23 is a schematic configuration diagram showing this conventional throttle control device for an internal combustion engine. This throttle control device includes an intake passage 101 for supplying intake air to an internal combustion engine.
Further, the first throttle valve 102 and the second throttle valve 103 are provided in series. The first throttle valve 102 is mechanically connected to an accelerator pedal 104 and is opened / closed in conjunction with an accelerator operation, and the second throttle valve 103 is opened / closed by a pulse motor 105. The accelerator pedal 104 is provided with an accelerator position sensor 106 for detecting an accelerator operation amount, and a detection signal thereof is input to a controller 107. The controller 107 calculates a throttle opening command value according to the accelerator operation amount according to a preset opening characteristic, and outputs a drive signal to the pulse motor 105 to set the actual opening of the second throttle valve 103 to throttle. Control to the opening command value.

Here, since the opening of the second throttle valve 103 is controlled by the pulse motor 105 at a position always closer to the opening than the opening of the first throttle valve 102, the intake air of the internal combustion engine during normal operation is controlled. The amount is determined by the opening of the second throttle valve 103. Also, the second
When an abnormality occurs in the throttle control system that controls the opening / closing of the throttle valve 103, the controller 10
7 is the pulse motor 105 and the second throttle valve 1
Hold 03 in the fully open position. Therefore, the intake air amount at the time of abnormality is determined by the opening degree of the first throttle valve 102, and the first throttle valve 10 is operated according to the accelerator operation.
2 is opened and closed, and the vehicle can continue running.

In this conventional throttle control device, the first throttle valve 102 is the accelerator pedal 1
Since it is opened and closed mechanically in conjunction with 04, it is possible to continue reliable throttle operation without being affected by an abnormality in the throttle control system.

[0009]

In the conventional throttle control device for an internal combustion engine, as described above, the opening degree of the second throttle valve 103 is normally set to the first throttle valve 1
The opening degree of 02 is controlled to the closed side, and the intake air amount is substantially adjusted by the second throttle valve 103. Therefore, when the second throttle valve 103 is opened due to the occurrence of an abnormality in the throttle control system, the intake air amount of the internal combustion engine increases to a value corresponding to the opening degree of the first throttle valve 102. Therefore, although not as great as the throttle control device described in the above-mentioned publication, the engine torque increases against the driver's intention, causing the driver to feel uncomfortable and uncomfortable, and thereafter, the operation amount of the accelerator pedal 104 is adjusted. It was necessary to fix it, which was not preferable in terms of accelerator operation feeling.

Therefore, the present invention suppresses an unnecessary increase in engine torque when an abnormality occurs in the throttle control system,
Consequently, it is an object of the present invention to provide a throttle control device for an internal combustion engine that can improve the accelerator operation feeling without giving the driver a feeling of strangeness.

[0011]

A throttle control device for an internal combustion engine according to a first aspect of the present invention, as shown in FIG.
A throttle driving means M3 for controlling the opening of the throttle valve M2 of the internal combustion engine M1 based on a predetermined throttle opening command value is provided, and the throttle driving means M is provided.
3 is provided with an accelerator interlocking means M4 for mechanically interlocking with the accelerator operation to open and close the throttle valve M2 on the open side, and when an abnormality occurs in the throttle control system, the throttle control by the throttle drive means M3 is stopped and the accelerator interlocking means is provided. In a throttle control device for an internal combustion engine that opens and closes a throttle valve M2 by M4, an engine torque when an abnormality occurs in the throttle control system and an engine torque after the throttle opening degree changes to the open side due to the abnormality occurrence are estimated. Based on the engine torque estimating means M5 and the engine torque estimated by the engine torque estimating means M5, the increase amount of the engine torque before and after the occurrence of the abnormality is calculated, and the increase amount of the engine torque in all cylinders of the internal combustion engine M1 is calculated according to the increase amount. A cylinder deactivation number setting means M6 for setting the cylinder deactivation number for suspending operation, and when an abnormality occurs in the throttle control system, Is intended to and a cylinder deactivation control means M7 for halting the particular cylinder corresponding to the cylinder deactivation speed set at Kikyu cylinder number setting means M6.

A throttle control device for an internal combustion engine according to a second aspect of the present invention is an accelerator return operation detecting means for detecting an accelerator return operation after an abnormality occurs in the throttle control system, and an accelerator return operation detecting means for the accelerator return operation detecting means. A cylinder deactivation ending means for terminating the cylinder deactivation control by the cylinder deactivation control means when an operation is detected.

[0013]

In the first aspect of the invention, the opening of the throttle valve M2 of the internal combustion engine M1 is controlled by the throttle drive means M3. For example, in the normal throttle control, a predetermined opening characteristic depending on the accelerator operation amount. Controlled by
If the traction control is in progress, the control is performed according to the slip amount of the drive wheels of the vehicle. When an abnormality occurs in the throttle control system, the throttle control by the throttle driving means M3 is stopped, and the throttle valve M2 is opened / closed by the accelerator interlocking means M4 mechanically interlocking with the accelerator operation on the further open side. Therefore, when the opening / closing by the throttle driving means M3 is changed to the opening / closing by the accelerator interlocking means M4, the throttle opening is changed to the open side to increase the engine torque.

The engine torque estimating means M5 at this time estimates the engine torque when an abnormality occurs and the engine torque after the throttle opening changes to the open side due to the abnormality occurrence. Then, based on these engine torques, the cylinder deactivation number setting means M
At 6, the number of cylinder deactivation is set according to the increase in engine torque,
The cylinder deactivation control means M7 deactivates a specific cylinder corresponding to the number of cylinder deactivated. Therefore, an increase in engine torque contrary to the driver's intention when an abnormality occurs is suppressed, and the operation can be continued without re-adjusting the accelerator operation amount.

According to the second aspect of the present invention, when the accelerator return operation detecting means detects the accelerator return operation of the driver after the abnormality of the throttle control system occurs, the cylinder deactivation control means deactivates the cylinder deactivation control means. The cylinder control is ended. Therefore, after that, all the cylinders of the internal combustion engine are activated, and it is possible to prevent an increase in vibration due to the deactivation of a specific cylinder.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A throttle control device for an internal combustion engine according to an embodiment of the present invention will be described below. FIG. 2 is a schematic configuration diagram showing a throttle control device for an internal combustion engine according to an embodiment of the present invention, and FIG. 3 is a perspective view showing the vicinity of a throttle valve to which the throttle control device for an internal combustion engine according to an embodiment of the present invention is applied. It is a figure.

First, a schematic structure of an internal combustion engine to which the throttle control device of this embodiment is applied will be described. As shown in FIG. 2, the internal combustion engine 1 is configured as a V-type 6-cylinder 4-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 intake air amount 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 / 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 to each cylinder via the intake manifold 6.

An injector 7 is installed in the intake manifold 6 corresponding to each cylinder, and the fuel injected from each injector 7 is mixed with intake air and supplied to each cylinder. This air-fuel mixture is introduced into the combustion chamber 9 of each cylinder as the intake valve 8 is opened and closed, and is burned by the ignition of the spark plug 10 to push down the piston 11 and apply torque to the crankshaft 12. The exhaust gas after combustion is discharged to the outside through the exhaust passage 14 as the exhaust valve 13 is opened and closed. A crank angle sensor 15 is installed near the crankshaft 12 and outputs a pulse signal every 30 degrees at the crank angle.

Next, the configuration around the throttle valve of the internal combustion engine thus constructed will be described. As shown in FIG. 3, the configuration around the throttle valve of the throttle control device of the present embodiment has a motor drive mechanism 21 for electrically opening and closing the throttle valve 5 with a DC motor 31, and the throttle valve 5 for accelerator operation. It is roughly divided into an accelerator interlocking mechanism 22 for interlocking and mechanically opening and closing.

First, the motor drive mechanism 21 will be described.
A throttle shaft 23 extends horizontally through the intake passage 2, and a 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 inside of the intake passage 2 to adjust the intake air amount. here,
The rotation direction of the throttle shaft 23 when opening the intake passage 2 to the throttle valve 5 is the opening direction, and the rotation direction of the throttle shaft 23 when opening the intake passage 2 is the closing direction. Both ends of the throttle shaft 23 project leftward and rightward (in the left-right direction in the drawing) from the intake passage 2, and a stopper lever 24 is fixed to the left end thereof. The stopper lever 24 is provided with an L-shaped bent portion 24a.
Two valve springs 25 are connected to the throttle shaft 23.
Is always biased in the opening direction. Further, a fully closed position stopper 26 is provided in the vicinity of the bent portion 24a, and the fully closed position stopper 26 is provided on the bent portion 24a of the stopper lever 24 when the throttle valve 5 is rotated to the fully closed position. It abuts and restricts further rotation.

A quarter circle driven gear 28 is rotatably attached to the right portion of the throttle shaft 23 via a bearing 27. The driven gear 28 is a pair of intermediate gears for reducing speed. It is in mesh with the drive gear 30 via 29. The drive gear 30 is fixed to the output shaft 31a of the DC motor 31, and the DC motor 31 rotationally drives the driven gear 28 in the closing direction via the drive gear 30 and the intermediate gear 29. A hook portion 28a is formed on one side of the driven gear 28 so as to project therefrom. The return spring 32 connected to the hook portion 28a is connected to the driven gear 28.
Is always biased in the opening direction, that is, in the direction opposite to the drive direction of the DC motor 31.

On the right side of the driven gear 28, a locking lever 33 is fixed to the throttle shaft 23, and the locking lever 33 is provided with an L-shaped bent portion 33a. The bent portion 33a is located on the closed side of the hook portion 28a of the driven gear 28,
The valve spring 25 causes the throttle shaft 23 to rotate and urge in the opening direction so that the throttle shaft 23 comes into contact with the hook portion 28a. Therefore, when the DC motor 31 is energized to generate torque, the driven gear 28 is rotated in the closing direction against the biasing force of the return spring 32 and the valve spring 25, and the latch lever 33 is rotated.
Also, the throttle valve 5 is rotationally driven in the closing direction together with the throttle shaft 23. When the DC motor 5 is de-energized, 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 installed at the right end of the throttle shaft 23, and the opening sensor 34 outputs a voltage Vth according to the opening of the throttle valve 5. On the other hand, the accelerator interlocking mechanism 22 will be described. On the left side of the throttle shaft 23, a guard shaft 41 is rotatably supported so as to be coaxially located.
The accelerator lever 42 fixed to the vehicle is connected to an accelerator pedal 44 of the vehicle via a control cable 43. A guard lever 45 is fixed to the right end of the guard shaft 41, and the guard lever 45 is always biased in the closing direction by a guard spring 46 connected to one side. The urging force of the guard spring 46 is set to be sufficiently stronger 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, together with the accelerator lever 42, are rotated in the opening direction via the control cable 43 while resisting the biasing force of the guard spring 46. It

An accelerator position sensor 47 is installed on the accelerator pedal 44. As will be described later, the DC motor 31 opens and closes the throttle valve 5 based on the accelerator operation amount Ap detected by the accelerator position sensor 47. . Since the characteristic of the throttle opening θth at this time generally increases as the accelerator operation amount Ap increases, when the accelerator operation is performed, the DC motor 31 is driven to electrically throttle the throttle. The valve 5 is opened and closed, and on the other hand, the transmission of the control cable 43 mechanically rotates the guard lever 45 in the same direction.

An L-shaped bent portion 45a is provided on one side of the guard lever 45, and the bent portion 45a is located on the open side of the bent portion 24a of the stopper lever 24. A certain amount of play is set between the two bent portions 45a and 24a, and this play is always secured when the throttle shaft 23 and the guard shaft 41 rotate in the same direction. Also,
As will be described later, when an abnormality in the throttle control system or a valve block occurs, the DC motor 31 is de-energized, so that the throttle valve 5 is rotated in the opening direction by the urging force of the valve spring 25. 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 and restricts further opening of the throttle valve 5, so that the opening degree of the throttle valve 5 is set to the guard lever 45.
Is restricted to a rotation 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, thereafter, the throttle valve 5 is mechanically opened / closed by the accelerator interlocking mechanism 22, and the vehicle can continue traveling. In addition, guard axis 4
A guard position sensor 48 is installed at the left end of 1 to detect the guard position θmg.

The guard lever 45 is formed with an arc-shaped elongated hole 45b centered on the guard shaft 41. The elongated hole 45b is formed.
The distal end of the operation rod 49a of the diaphragm actuator 49 is fitted therein so as to be movable along the long hole 45b. During normal traveling, as shown in the figure, the operating rod 49a of the diaphragm actuator 49 is held in an extended state, and the guard lever 45 rotates in response to the accelerator operation while being allowed by the elongated hole 45b. Further, during cruise control traveling, the operating rod 49a of the diaphragm actuator 49 contracts to rotate the guard lever 45 in the opening direction. Therefore, even if the accelerator is not operated, the guard position is largely changed in the opening direction. Therefore, the DC motor 31 can operate the throttle valve 5 in the opening direction to maintain the traveling speed set by the driver. It will be possible.

Further, the engaging claw 45c formed integrally with the guard lever 45 is the operating rod 50 of the thermowax 50.
The operation rod 50 of this thermo wax 50 is engaged with a.
a expands and contracts according to the cooling water temperature of the internal combustion engine. For example, as shown in the figure, when the temperature of the cooling water is high after completion of warming up, the operation rod 50a extends so that the guard lever 45 rotates in the closing direction. Further, when the cooling water temperature is low as in the cold start, the operation rod 50a contracts so that the guard lever 45 rotates in the opening direction. And, as with the cruise control running described above,
By operating the throttle valve 5 in the opening direction with the DC motor 31, it becomes possible to perform idle-up.

Next, the operation of the above-mentioned mechanism around the throttle valve will be described collectively. FIG. 4 is an explanatory diagram schematically showing the operating principle around the 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 throttle valve 5 is on the upper side.
Is the opening direction, and the downward direction is the closing direction. As shown in the figure, the guard lever 45 is biased in the closing direction by a guard spring 46, and the guard position by the guard lever 45 is determined by the operation amount of the accelerator pedal 44, the displacement amount of the operation rod 49a of the diaphragm actuator 49, and the thermostat. Wax 5
It is determined by the displacement amount of the operating rod 50a of 0. Then, for example, when the driver depresses the accelerator pedal 44, the guard lever 45 is operated in the opening direction (pulled upward in the figure) against the biasing force of the guard spring 46, and the guard position changes to the opening direction. .

The throttle valve 5 is biased in the opening direction by a valve spring 25, and similarly, the DC motor 31
Is urged in the opening direction by a 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 obstructs it. Therefore, both springs 2
The opening of the throttle valve 5 is determined by the balance between the urging forces of the motors 5, 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 DC motor 31 is de-energized, the valve spring 25 biases the throttle valve 5 in the opening direction, and the return spring 32 causes the driven gear 2 to move.
8 is biased in the opening direction.

Next, the electrical construction of the throttle control device of this embodiment will be described. As shown in FIG. 2, the electronic control unit 61 of the throttle control unit includes a CPU 62 and 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
It is composed of 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 the processes according to these programs. RAM64 is C
The processing data executed by the PU 62 is temporarily stored.

The CPU 62 includes the air flow meter 4
Intake air amount Qa detected at
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 converted into digital values by the A / D conversion circuit 66 and input.

Then, the CPU 62, for example, calculates the engine speed Ne calculated from the pulse signal of the crank angle sensor 15.
Based on the intake air amount Qa and the intake air amount Qa, the current fuel injection amount required by the internal combustion engine 1 is calculated, and a control signal having a pulse width corresponding to the fuel injection amount is output to the injector drive circuit 65. Further, the CPU 62 calculates a fuel cut cylinder number Nfc (0 to 6) when an abnormality or a valve block of a throttle control system described later occurs, and controls the specific cylinder according to the fuel cut cylinder number Nfc. Stop outputting the signal. The injector drive circuit 65 causes the injector 7 to operate for a time corresponding to the pulse width input from the CPU 62.
Energize to inject the required amount of fuel and
Fuel injection is stopped for a specific cylinder for which a control signal is not input from U62.

On the other hand, the CPU 62 controls the accelerator operation amount Ap.
Based on the engine speed Ne and the engine speed Ne, a throttle opening command value θcmd, which is a target value for throttle opening control, is determined, and further, a throttle command voltage Vcmd corresponding to the throttle opening command value θcmd is determined. Further, the CPU 62
When various abnormalities, which will be described later, occur in the throttle function of the internal combustion engine 1, a control signal is output to the lamp drive circuit 68 to output a warning lamp 69 provided in the driver's seat of the vehicle.
Light up.

The DC motor drive circuit 71 of the throttle control device includes a PID control circuit 72 and PWM (pulse width modulation).
It is composed of a circuit 73 and a driver 74. The throttle command voltage Vcmd calculated by the CPU 62 as described above
Is converted into an analog value by the D / A conversion circuit 67 and input to the PID control circuit 72. PID control circuit 72
Is the throttle command voltage Vcmd and the throttle opening sensor 3
Based on the output voltage Vth of 4, the proportional / integral / derivative operation is executed to reduce the deviation, and the control amount of the DC motor 31 is calculated. The PWM circuit 73 inputs the calculated control amount, converts the control amount into a corresponding duty ratio signal, and the driver 74 drives the DC motor 31 in accordance with the duty ratio signal to determine the actual throttle opening θth. Adjust 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. 5 is a flow chart showing a throttle control routine executed by the CPU of the internal combustion engine throttle control device according to one embodiment of the present invention. FIG. 6 shows the internal combustion engine throttle control device according to one embodiment of the present invention. FIG. 7 is a flowchart showing a fail determination routine executed by the CPU.
FIG. 8 is a flowchart showing a first 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. FIG. 8 is a throttle control device for an internal combustion engine according to one embodiment of the present invention. FIG. 6 is an explanatory diagram showing an actual control delay of the throttle opening with respect to the throttle opening command value.

FIG. 9 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 which is an embodiment of the present invention, and FIG. 10 is an embodiment of the present invention. FIG. 11 is a flowchart showing an accelerator interlocking mechanism abnormality determination routine executed by a CPU of a throttle control device for an internal combustion engine. FIG. 11 is a CPU of the throttle control device for an internal combustion engine according to an embodiment of the present invention.
FIG. 12 is a flow chart showing a spring loss determination routine executed by the CPU, and FIG. 12 is a flow chart showing a valve lock determination routine executed by the CPU of the throttle control device for the internal combustion engine according to the embodiment of the present invention.

The throttle control routine of FIG. 5 is executed every 8 msec. First, the CPU 62 executes a fail determination process in step S1. <Fail Judgment Routine> When the fail judgment routine is called, the CPU 62 proceeds to step S10 of FIG. Then, the first throttle control abnormality determination process is performed in step S10, the second throttle control abnormality determination process is performed in step S20, the accelerator interlocking mechanism abnormality determination process is performed in step S30, and the spring breakage determination process is performed in step S40. Valve block determination processing is executed in S50. <First Throttle Control System Abnormality Determination Routine> The details of each abnormality determination process will be described below. When the first throttle control system abnormality determination routine is called in step S10, the CPU 62 proceeds to step S11 in FIG. To do. First, in step S11, it is determined whether or not the fail flag XFAIL1 indicating the abnormality occurrence of the throttle control system has already been set by the first throttle control system abnormality determination routine or the second throttle control system abnormality determination routine described later. To judge. Fail flag XFAIL
If 1 is not set, the current throttle opening for control (hereinafter, simply referred to as "control estimated throttle opening") is determined based on the throttle opening command value θcmd which is the target value for throttle opening control in step S12. ) Calculate θcmdo according to the following formula.

Θcmdo = K1 · θcmdi + K2 · θcmdi-1 +
K2 · θcmdoi-1 + K3 · θcmdoi-2 where K1 to K3 are preset constants and θcm
di is the current throttle opening command value, θcmdi-1 is the previous throttle opening command value, θcmdoi-1 is the previous control estimated throttle opening, and θcmdoi-2 is the control estimated throttle opening two times before.

As shown in FIG. 8, when the throttle opening command value θcmd changes, the actual control estimated throttle opening θcmdo follows with a predetermined delay, and this control delay is caused by the DC motor 31 and its drive circuit 71. It is determined by the characteristics of. The above equation is created by approximating the DC motor 31 and the drive circuit 71 with a second-order lag filter, and according to this equation, the throttle opening command value θcmd
The estimated control throttle opening θcmdo calculated from the above 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 estimated control 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. It is determined whether it is less than θa. When an affirmative decision is made in step S13 (| θcmdo-θth | <θa), step S1
At 4, the counter Ca that counts the duration of the abnormal state is reset. Further, in step S15, the throttle opening θth at this time is stored in the RAM 64 as the throttle opening θsave during failure, and the process proceeds to step S16.

If a negative decision is made in step S13 (.vertline..theta.cmdo-.theta.th.gtoreq..theta.a), the counter Ca is incremented by "+1" in step S17.
Move to 16. Then, in step S16, the counter C
When it is determined whether or not a is less than a predetermined value KCa set in advance, and when a positive determination is made (Ca <KCa), this routine is ended, and when a negative determination is made (Ca ≥KC
a), the fail flag XFAIL is determined in step S18.
Set 1 to end this routine.

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, when a certain amount of difference continues between the control estimated throttle opening θcmdo and the actual throttle opening θth, an abnormality occurs in the throttle control system for some reason, It can be considered that the throttle opening control by the DC motor 31 is not normally executed. Therefore,
At this time, the CPU 62 determines that the throttle control system has failed, and the fail flag XFAIL1 is set. And this fail flag XF
When the first throttle control system abnormality determination routine is executed again after AIL1 is set, step S11
Is answered in the affirmative and the routine is immediately terminated. Therefore, the process of step S15 is not executed, and the RAM 6
4 is the throttle opening θ at the time when the fail judgment is made.
th continues to be stored as the throttle opening θsave at the time of failure. <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 6
2 shifts to step S21 of FIG. Similar to step S11 of the first throttle control system abnormality determination routine,
First, in step S21, the fail flag XFAIL
It is determined whether 1 has already been set, and if the fail flag XFAIL1 has not been set, the process proceeds to step S22. Next, at step S22, the guard position θmg detected by the guard position sensor 48 and the throttle opening θ detected by the throttle opening sensor 34.
It is determined whether or not the difference from th is greater than or equal to a predetermined value θb set in advance. 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,
In step S24, the throttle opening θth at this time is stored in the RAM 64 as the throttle opening θsave during failure, and the process proceeds to step S25.

If a negative decision is made in step S22 (│θmg-θth│ <θb), the counter Cb is incremented by "+1" in step S26, and step S2 is executed.
Go to 5. Then, in step S25, the counter Cb
Is less than a predetermined value KCb set in advance, and when a positive determination is made (Cb <KCb), this routine is ended, and when a negative determination is made (Cb ≥ KCb).
) To the fail flag XFAIL in step S27.
Set 1 to end this routine.

Here, the actual throttle opening θth should always be located on the closing side with a difference of a predetermined value or more with respect to the guard position θmg. Therefore, when the state where the difference between the guard position θmg and the throttle opening θth is narrowed continues as described above, the DC motor 31 is used as in the first throttle control system abnormality determination routine described above. The fail flag XFAIL1 is set because the throttle opening control is not normally executed. After setting the fail flag XFAIL1, an affirmative decision is made in step S21 and step S24.
Since the above process is not executed, the throttle opening θth at the time when the fail determination is made is continuously stored as the fail throttle opening θsave in the RAM 64. <Accelerator Link Mechanism Abnormality Judgment Routine> On the other hand, when the accelerator link mechanism abnormality judgment routine is called in step S30 of the fail judgment routine, the CPU 62 proceeds to step S31 in FIG. First, this step S31
In step S32, it is determined whether the internal combustion engine 1 is operating normally, and if cruise control or cold start is not being performed, it is determined that the engine is operating normally and the process proceeds to step S32. Next, in step S32, the guard position sensor 4
It is determined whether the absolute value of the difference between the guard position θmg detected at 8 and the accelerator operation amount Ap detected at the accelerator position sensor 47 is less than a preset predetermined value θc. When an affirmative judgment is made in step S32 (|
For 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 decision is made in step S32 (│θmg-Ap│ ≧ θc), the counter Cc is incremented by "+1" in step S35, and step S3 is executed.
Go to 4. Then, in step S34, the counter Cc
Is less than a predetermined value KCc set in advance, and when a positive determination is made (Cc <KCc), this routine is ended, and when a negative determination is made (Cc ≥ KCc
), The fail flag XFAIL2 indicating the abnormality occurrence of the accelerator interlocking mechanism 22 is set in step S36, and this routine is ended.

Here, the guard position θmg when cruise control or cold start is not executed is
Diaphragm actuator 49 and thermo wax 50
Since it has not been changed to the opening direction by, it should always correspond to the accelerator operation amount Ap. Therefore, as described above, when a certain amount of 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 according to the accelerator operation amount Ap cannot be expected. Therefore, at this time, the CPU 62 makes a fail determination of the accelerator interlocking mechanism 22 and sets the fail flag XFAIL2.

When it is determined in step S31 that the internal combustion engine 1 is not in normal operation, it is determined whether or not there is an abnormality because the guard position θmg has already been changed to the open side by the diaphragm actuator 49 and the thermowax 50. Immediately, this routine is terminated because it is impossible. <Spring breakage loss determination routine> When the spring breakage loss determination routine is called in step S40 of the fail determination routine, the CPU 62 proceeds to step S41 in FIG. First, based on the accelerator operation amount Ap detected by the accelerator position sensor 47 in step S41, it is determined whether the internal combustion engine 1 is in the idle operation. During idle operation, PW is performed in step S42.
The duty ratio signal is input from the M circuit 73, and the average value DutyAV of the duty ratio Duty per predetermined time is
It is determined whether or not it is equal to or larger than a predetermined value Duty set in advance. When an affirmative judgment is made in step S42 (Duty AV ≧ D
utyd), the counter Cd that counts the duration of the abnormal state is reset in step S43, and step S4
Go to 4.

When a negative determination is made in step S42 (DutyAV <Dutyd), the counter Cd is incremented by "+1" in step S45, and the process proceeds to step S44. Then, in step S44, it is determined whether the counter Cd is less than a preset predetermined value KCd,
When the determination is affirmative (Cd <KCd), this routine is ended, and when the determination is negative (Cd ≥ KCd), the fail flag XFAIL3 indicating the occurrence of spring breakage is set in step S46, This routine ends. Here, during idle operation of the internal combustion engine 1, I
Since the throttle valve 5 is held at a substantially constant opening degree near the fully closed state by the SC control, the total sum of the urging forces of the valve spring 25 and the return spring 32 also has a substantially constant value. Therefore, the average value DutyAV of the duty ratio Duty given to the DC motor 31 in order to resist the biasing force should have converged to a substantially constant value, and the state where the average value DutyAV is lower than usual continues. When it occurs, it can be considered that there is a possibility that one of the springs 25 and 32 will be damaged and the throttle opening control will not be performed smoothly.
Therefore, at this time, the CPU 62 makes a failure judgment of the spring breakage and sets the fail flag XFAIL3.

The spring 2 is calculated based on the average value DutyAV.
The reason why the cut loss of 5 and 32 is determined is that the duty ratio Duty at this time is fluctuating so as to maintain the idling rotation speed, and therefore an accurate determination cannot be expected from the duty ratio Duty itself. Further, when it is determined in step S41 that the internal combustion engine 1 is not in the idle operation, 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 have the desired values. If it is not reached and it is not possible to determine the presence or absence of cutting loss, this routine is immediately terminated. <Val Block Determination Routine> When the valve lock determination routine is called in step S50 of the fail determination routine, the CPU 62 proceeds to step S51 of FIG. First, in step S51, the PWM circuit 73
Input the duty ratio signal from the
It is determined whether or not uty is less than a predetermined value Duty set in advance. When a positive determination is made in step S51 (Dut
If y <Dutye), the counter Ce for counting the duration of the abnormal state is reset in step S52, and the process proceeds to step S53.

When a negative determination is made in step S51 (Duty ≥ Duty), the counter C is determined in step S54.
e is incremented by "+1" and the process proceeds to step S53. Then, in step S53, it is determined whether or not the counter Ce is less than a predetermined value KCe set in advance, and when a positive determination is made (Ce <KCe), this routine is ended, and when a negative determination is made ( Ce ≧ KCe), the fail flag XFAIL4 indicating the occurrence of a valve block is set in step S55, and this routine is ended.

Here, when a valve block occurs due to a foreign substance or the like that has fallen into the intake passage 2, the DC motor 3
Even if the throttle valve 5 is opened / closed at 1, the actual throttle opening θth does not reach the throttle opening command value θcmd. Therefore, the duty ratio Duty at this time is drastically increased by the control of the PID control circuit 72, and if the situation continues for a time that cannot be continued in the normal control state, it is considered that the throttle valve 5 has become unable to open / close. be able to. Therefore, at this time, the CPU 62 makes a fail determination of the valve block and the fail flag XFAIL4 is set.

FIG. 13 is an explanatory view showing a map for determining the throttle opening command value at the time of normal control in the throttle control device for an internal combustion engine which is an embodiment of the present invention, FIG.
4 is an explanatory view showing a map for determining a throttle command voltage in a throttle control device for an internal combustion engine which is an embodiment of the present invention, and FIG. 15 is a limp in a throttle control device for an internal combustion engine which is an embodiment of the present invention. FIG. 16 is an explanatory view showing a map for determining the throttle opening command value during home control, and FIG. 16 is a time chart when an abnormality occurs in the throttle control system in the throttle control device for the internal combustion engine which is one embodiment of the present invention. .

When each fail judgment process is completed as described above, the CPU 62 returns to the throttle control routine of FIG. 5, and all fail flags XFA are returned in step S2.
It is determined whether IL1 to XFAIL4 have been cleared. In step S2 all fail flags XFAIL
When 1 to XFAIL4 are cleared (XFAIL
1 to 4 = 0), all throttle functions of the internal combustion engine 1, such as the throttle control system and the accelerator interlocking mechanism 22 are included.
Assuming that the above is normal, normal throttle control is executed in the processing from step S3.

That is, the CPU 62 executes step S3 in FIG.
In accordance with a map stored in advance in the ROM 63 shown in FIG. 2, from 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, the normal throttle control is performed. The throttle opening command value θcmd at is determined.

Then, the CPU 62 proceeds to step S4 in FIG.
According to the map previously stored in the ROM 63 shown in 4,
Throttle opening command value θcmd to throttle command voltage V
Determine cmd. Furthermore, the throttle command voltage Vcmd
Is output to the PID control circuit 72 of the DC motor drive circuit 71 via the D / A conversion circuit 67 in step S5, and this throttle control routine is ended.

The throttle command voltage Vcmd output from the CPU 62 is compared with the output voltage Vth of the throttle opening sensor 34 in the PID control circuit 72, and proportional / integral / derivative operations are executed to reduce the deviation. The 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 motor 31 is driven by the driver 74 according to the duty ratio signal. 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 to adjust the actual throttle opening θth to the throttle opening command value θcmd. It

On the other hand, when any of the fail flags XFAIL1 to XFAIL4 is set in step S2 (XFAIL1 to 4 ≠ 0), step S6 is performed.
Then, a control signal is output to the lamp drive circuit 68 to turn on the warning lamp 69. Then, the fail flags XFAIL1 to XFAIL set in step S7.
When the type of L4 is determined and the fail flag XFAIL3 is set, the valve spring 25 and the return spring 3
2 is considered to have been cut off, the process proceeds to step S3, and the normal throttle control is executed as in the case where all the throttle functions described above are normal.

That is, even if one of the valve spring 25 and the return spring 32 is cut off, the running of the vehicle is not hindered immediately. Therefore, the warning lamp 69 is turned on to prompt the driver for inspection and repair. Of. When it is determined in step S7 that the fail flag XFAIL2 is set, it is considered that excessive play is occurring in the accelerator interlocking mechanism 22, the process proceeds to step S8, and so-called limp home control is executed. That is, the CPU 6
2 is the accelerator position sensor 47 according to the map stored in advance in the ROM 63 shown in FIG. 15 in step S8.
The throttle opening command value θcmd during the limp home control is determined from the accelerator operation amount Ap detected at.
As is clear from a comparison with FIG. 13, a smaller throttle opening command value θcmd is set in this limp home control at the same accelerator operation amount Ap. Then, the throttle command voltage Vcmd is determined from the throttle opening command value θcmd in step S4, 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 is reduced regardless of the accelerator operation, and the driver is warned by the warning lamp 6
It is possible to promptly detect an abnormality based on this torque decrease without needing to visually check 9. Further, since the throttle opening degree control is performed even after switching to the limp home control, the vehicle can continue to run, and the throttle opening degree is suppressed, so that the driver's careful driving is encouraged. .

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

Since the opening / closing of the throttle valve 5 is blocked when the valve block occurs, 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 freely opened and closed, so that DC
When the energization of the motor 31 is stopped, the throttle valve 5 is rotated in the opening direction by the urging force of the valve spring 25 and the return spring 32, and the throttle opening θth changes to the guard position θmg, as shown in FIG. Then, 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 discontinuation of energization of the DC motor 31, when a throttle control abnormality and a valve block occur, so-called fuel cut is performed to stop fuel injection to a specific cylinder of the internal combustion engine 1. Then, the cylinder is held in the idle state. Therefore, the fuel injection control process executed by the CPU 62 will be described next. << Fuel Injection Control Process >> FIG. 17 is a flowchart showing a fuel injection control routine executed by the CPU of the throttle control device for an internal combustion engine which is an embodiment of the present invention, and FIG. 18 is a flowchart of an internal combustion engine which is an embodiment of the present invention. Throttle control device C
It is a flow chart which shows a fuel cut flag setting routine which PU performs.

The fuel injection control routine of FIG. 17 is executed every 720 degrees at the crank angle of the internal combustion engine 1. First, C
Based on 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, the PU 62 calculates the current internal combustion engine 1
Calculates the fuel injection amount required by the engine and sets the pulse width corresponding to the fuel injection amount. Next, in step S102, a fuel cut flag setting process is executed. <Fuel Cut Flag Setting Routine> When the fuel cut flag setting routine is called, the CPU 62 proceeds to step S111 of FIG.

Now, it is assumed that abnormality of the throttle control system and valve block do not occur and both the fail flag XFAIL1 and the fail flag XFAIL4 are cleared. In step S111, the CPU 62 determines whether or not the fail flag XFAIL1 or the fail flag XFAIL4 which has been cleared so far is set. Which fail flag XFAIL1, X
Since FAIL4 is not set either, step S11
Move to 2 and either fail flag XFAIL
1, it is determined whether or not XFAIL4 is currently set. As in step S111, since neither of the fail flags XFAIL1 and XFAIL4 has been set, this routine ends. That is, no action is taken in this routine unless an abnormality in the throttle control system or a valve lock has occurred.

Further, when the fail determination is made due to the abnormality of the throttle control system or the occurrence of the valve block and either of the fail flags XFAIL1 and XFAIL4 is set, the routine proceeds from step S111 to step S113, and the fuel cut processing is performed. Fuel cut flag X indicating execution of
Set FC. Next, the process proceeds to step S114 through step S112, and 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. After that, as long as the accelerator is operated, the processes of step S111, step S112, and step S114 are repeatedly executed, and step S1 is performed.
At 14, when the accelerator operation amount Ap becomes 0 (Ap = 0),
In step S115, the fuel cut flag XFC is cleared.

Therefore, as shown in FIG. 16, the fuel cut flag XFC is held in the set state from when the fail judgment is made until 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. 17 and determines in step S103 whether the fuel cut flag XFC is cleared. When the fuel cut flag XFC is cleared (XFC =
0), that is, when there is no abnormality in the throttle control system or valve block, the routine proceeds to step S104, where the number Nfc of fuel cut cylinders is set to 0 (Nfc = 0), and at step S105, the above is performed for all cylinders. Step S10
The control signal having the pulse width set in 1 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 are operated. That is, in this case, normal fuel injection control is executed.

When the fuel cut flag XFC is set in the step S103 (XFC = 1),
That is, when the abnormality of the throttle control system or the valve block occurs, the process proceeds to step S106 and it is determined whether or not the fail flag XFAIL4 is set. When the fail flag XFAIL4 is set, it is considered that there is an abnormality in the valve block, and the fuel cut cylinder number Nfc is set to 6 in step S107 (Nfc
= 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 deactivated. Therefore, when this valve block 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 traveling of the vehicle is stopped. If the fail flag XFAIL1 is set in step S106, it is considered that there is an abnormality in the throttle control system, and step S108 is performed.
Then, the process for setting the fuel cut cylinder number Nfc is executed.

FIG. 19 is a flow chart showing a fuel cut cylinder number setting routine executed by the CPU of the throttle control device for an internal combustion engine according to the embodiment of the present invention. FIG. 20 is a throttle for the internal combustion engine according to the embodiment of the present invention. Explanatory diagram showing a map for determining the estimated torque in the control device,
FIG. 21 is an explanatory view showing a map for determining the number of fuel cut cylinders in the throttle control device for an internal combustion engine which is an embodiment of the present invention.

When the routine for setting the fuel cut cylinder number Nfc is called, the CPU 62 causes the CPU 62 to execute step S121 in FIG.
Move to. First, in this step S121, the RAM according to the map stored in advance in the ROM 63 shown in FIG.
Throttle opening at fail θsave stored in 64
And the engine speed Ne detected by the crank angle sensor 15
Therefore, the estimated failure torque Tfa, which is the engine torque of the internal combustion engine 1 at the time of the failure determination, is determined. In addition,
The characteristics of the map in FIG. 20 are obtained from the actual torque characteristics of the internal combustion engine 1. 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. , Estimated torque Tfa when fail
Is also suppressed to a small value.

Then, in step S122, as shown in FIG.
According to the map of 0, the accelerator operation amount Ap detected by the accelerator position sensor 47 and the crank angle sensor 1
The estimated post-failure torque Tap, which is the current engine torque after the fail determination, from the engine speed Ne detected in
To decide. Further, in step S123, the estimated torque during failure Tfa is subtracted from the estimated torque after failure Tap,
The torque increment ΔT (ΔT = Tap−Tfa) is calculated. The torque increase amount ΔT indicates the increase amount of the engine torque when the throttle opening θth changes in the opening direction to the guard position θmg due to the stop of energization of the DC motor 31.

Here, as shown in the map of FIG. 13, the throttle opening command value θcmd is approximated to the accelerator operation amount Ap in the region near full close and full open, and compared with the accelerator operation amount Ap in the intermediate region. It is set to a lower value, and in particular in the intermediate region, it is set to a lower value as the engine speed Ne is lower. Therefore, the amount of change when the throttle opening θth changes to the guard position θmg at the time of fail determination is
The amount ΔT of torque increase changes depending on the accelerator operation amount Ap and the engine speed Ne at that time. Therefore, by the processes of steps S121 to S123, the engine torques before and after the failure determination (the estimated torque during failure Tfa and the estimated torque after failure Tap) are estimated, and the torque increase amount ΔT is obtained.

Then, in step S124, the CPU 62 determines the number of fuel cut cylinders Nfc from the torque increase amount ΔT according to the map stored in advance in the ROM 63 shown in FIG. 21, and ends this routine. As is apparent from the figure, the number of fuel cut cylinders Nfc at this time is set to a large value as the torque increase amount ΔT increases. Then C
The PU 62 returns to the fuel injection control routine of FIG. 17, and outputs a control signal to the injector drive circuit 65 for the cylinders according to the fuel cut cylinder number Nfc in step S105.
As a result, the injector drive circuit 65 energizes a number of injectors 7 corresponding to the number Nfc of fuel cut cylinders to inject fuel, and these 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. 16, the fuel is increased based on the torque increase ΔT. The number of cut cylinders Nfc is set. Then, the fuel is cut off from a specific cylinder corresponding to the number of fuel cut cylinders Nfc, and the cylinder is stopped, and the engine torque is reduced by an amount substantially equal to the torque increase ΔT. That is, the fluctuation of the engine torque before and after the failure determination is prevented, and the vehicle acceleration G after the failure is
It is maintained at a very small value as before the fail judgment. Therefore, the increase of the engine torque contrary to the driver's intention is surely suppressed, and the operation can be continued without re-adjusting the accelerator operation amount Ap.

If all cylinders continue to operate without fuel cut, the engine torque increases with the throttle opening θth, so that the vehicle acceleration G is a two-dot chain line contrary to 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, the throttle opening θ
After th has changed to the guard position θmg, the throttle valve 5 is opened / closed by 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.

After the fail judgment, when the driver's accelerator operation amount Ap for stopping the vehicle gradually decreases, the post-fail estimated torque Tap determined in step S122 of FIG. 19 decreases, and the torque increase in step S123 increases. With the amount ΔT, the number Nfc of fuel cut cylinders in step S124 gradually decreases. Then, as shown in FIG. 16, the accelerator operation amount Ap is the throttle opening θ at the time of the failure.
When the number of fuel cut cylinders Nfc returns to 0 when the fuel consumption is reduced to save, and the accelerator operation amount Ap further decreases to 0, the fuel cut flag XF is determined in step S115 of FIG.
C is cleared. Therefore, when the vehicle is restarted by the accelerator operation, step S1 in FIG.
At 04, the number Nfc of fuel cut cylinders is held at 0, and the normal fuel injection control for injecting fuel to all cylinders is executed.

That is, the throttle control device of the present embodiment is intended to suppress an increase in the engine torque when the throttle opening θth is opened to the guard position θmg by the fail judgment, and in the subsequent running, the accelerator Although the throttle valve seems to open slightly with respect to the manipulated variable Ap, it is not dealt with as it does not hinder traveling. Moreover, as will be described later, the number of fuel cut cylinders Nfc
Although the cylinder for which the fuel is cut is determined in consideration of the rotational balance of the internal combustion engine 1, the internal combustion engine 1 is
It is unavoidable that the vibration of the is increased. Therefore, by holding the fuel cut cylinder number Nfc at 0 when the accelerator operation amount Ap becomes 0 as described above, the increase in vibration due to the deactivation of the cylinder is prevented after the failure determination.

For reference, the above step S124
An example of selection of fuel cut cylinders according to the number Nfc of fuel cut cylinders executed in step S6 will be described. FIG. 22 is an explanatory diagram showing a map for determining the cylinder for which fuel injection is to be stopped, from the number of fuel cut cylinders in the throttle control device for an internal combustion engine which is one embodiment of the present invention.

As described above, the internal combustion engine 1 of this embodiment has V
It is a type 6 cylinder, and its 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. 22 is defined not as the cylinder number but as the cylinder to which the fuel is first injected after the fail determination is “1”. Therefore, for example, when the fail determination is made at the time when the fuel injection into the cylinder # 4 is completed and the fuel cut cylinder number Nfc is set to 3, the fuel cut cylinders are "1", "3", "5". Is set, but since the next fuel injection cylinder is # 5,
The fuel is cut off from cylinders # 5, # 1 and # 3. Incidentally, as a matter of course, the fuel cut cylinder shown in the figure is determined in consideration of the rotational balance of the internal combustion engine 1.

As described above, in this embodiment, the internal combustion engine M1
The internal combustion engine 1 functions as, the throttle valve 5 functions as the throttle valve M2, and the DC motor 31 functions as the throttle drive means M3. Also, the accelerator interlocking means M
4, the accelerator interlocking mechanism 22 performs the processing of step S121 and step S122 as the engine torque estimating means M5, and the CPU 62 determines the cylinder deactivation number setting means M6.
As a result, the CPU 62 when executing the processing of steps S123, S124, and S105 functions as the cylinder drive control means M7, and the injector drive circuit 65 and the injector 7 function as the cylinder deactivation control means M7.

Further, in this embodiment, the accelerator position sensor 47 functions as an accelerator return operation detecting means,
Steps S103 and S10 as a cylinder end means
4, CPU62 when performing the process of step S114, step S115 functions. As described above, the throttle control device for the internal combustion engine of the present embodiment controls the opening / closing of the throttle valve 5 of the internal combustion engine 1 with a predetermined opening characteristic according to the accelerator operation amount Ap detected by the accelerator position sensor 47. A motor 31 is provided, and an accelerator interlocking mechanism 22 that opens and closes the throttle valve 5 mechanically interlocking with accelerator operation on the opening side of the DC motor 31 is provided, and throttle control by the DC motor 31 is performed when an abnormality occurs in the throttle control system. Then, in the throttle control device for the internal combustion engine in which the throttle interlock mechanism 22 drives the throttle valve 5 to open and close, the estimated torque during failure Tfa is determined from the throttle opening θsave during failure and the engine speed Ne, and the accelerator The post-failure estimated torque Tap is determined from the manipulated variable Ap and the engine speed Ne, Estimated torque Tfa, to calculate the torque increment ΔT of about determination fail based on the Tap, the CPU62 for setting the fuel-cut number Nfc of the internal combustion engine 1, the CPU6
The injector drive circuit 65 and the injector 7 are provided to cut off fuel from a specific cylinder and stop the fuel supply in accordance with the number Nfc of fuel cut cylinders set in 2.

Therefore, when an abnormality occurs in the throttle control system, the torque increase amount ΔT before and after the fail judgment is made.
From this, the number Nfc of fuel cut cylinders is set, and the fuel is cut off for a specific cylinder correspondingly, and the engine torque is reduced. Therefore, an increase in the engine torque contrary to the driver's intention when the throttle opening θth changes in the opening direction due to the suspension of the energization of the DC motor 31 is reliably suppressed. Therefore, the driver can continue the driving without re-adjusting the accelerator operation amount Ap, and the feeling of throttle operation can be greatly improved.

Further, the throttle control system for an internal combustion engine according to the present embodiment, when an accelerator return operation is detected by the accelerator position sensor 47, which detects an accelerator return operation after a fail judgment, The CPU 62 is provided with the fuel cut cylinder number Nfc set to 0 and performing fuel injection to all cylinders.
This structure corresponds to the invention of claim 2.

Therefore, after the failure is judged and the accelerator return operation is performed, the fuel injection is performed to all the cylinders, so that the increase in vibration due to the suspension of the cylinders is prevented. Therefore, the traveling of the vehicle can be continued without impairing the comfort of the vehicle interior. By the way, in the above embodiment, the electric throttle control according to the predetermined opening characteristic by the DC motor 31 and the mechanical opening / closing drive linked with the accelerator operation by the accelerator interlocking mechanism 22 are performed by the single throttle valve 5 It was embodied as a throttle control device to be operated by. However, when the present invention is carried out, the present invention is not limited to this, and when an abnormality occurs in the throttle control system and the throttle opening θth changes to the open side due to the interruption of the energization of the DC motor 31, It suffices that the specific cylinder can be deactivated to suppress the increase of the engine torque. Therefore, for example, it may be embodied in the throttle control device including the pair of throttle valves shown in FIG. 23 described in the related art. In this case, when the second throttle valve 103 is held in the fully open state due to the occurrence of the abnormality, both throttle valves 10 immediately before that are opened.
An increase in engine torque can be suppressed by calculating the torque increase ΔT from the opening difference between 2, 103 and deactivating the number of cylinders corresponding to the torque increase ΔT.

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, the intake air amount Qa or the intake pipe pressure Pm may be estimated instead of these parameters. That is, the torque increase amount ΔT is estimated as the estimated torque during failure Tfa = intake air amount Qa or intake pipe pressure Pm at the time of failure occurrence, and the estimated torque after failure Tap = intake air amount Qa after intake failure determination or the intake pipe pressure Pm. Good.

In the above embodiment, the control estimated throttle opening θ is determined by the first throttle control system abnormality determination routine.
When a certain degree of difference continuously occurs between cmdo and the actual throttle opening θth, and when the second throttle control system abnormality determination routine narrows the difference between the guard position θmg and the throttle opening θth. Is continuously generated,
The throttle control system was judged as fail. However, the abnormality of the throttle control system in the present invention is not limited to this, and the throttle control by the DC motor 31 becomes inexecutable, and all situations requiring mechanical throttle operation by the accelerator interlocking mechanism 22. including. Therefore, for example, when the mechanical abnormality of the motor control mechanism 22 occurs, the failure determination of the throttle control system may be performed.

Further, in the above embodiment, the normal throttle control for controlling the traveling of the vehicle is performed by the DC motor 31, but the present invention is not limited to this, and 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 controlled to open and close. Therefore, for example, the actual Kaihei 2-
As in the throttle control device described in Japanese Patent No. 37245, the present invention can be applied to throttle control for traction control (hereinafter, simply referred to as "TRC"). Explaining the example of the publication, this throttle control device is provided with a pair of throttle valves, and one main throttle valve is mechanically interlocked with an accelerator operation to be opened and closed to drive the vehicle. Fulfill. The other auxiliary throttle valve is
When slippage occurs in the drive wheels of the vehicle, the TRC controls it to the close side, and plays a role of reducing engine torque and suppressing slippage. Here, as described in the publication,
When an abnormality occurs in the throttle control system during the TRC, the auxiliary throttle valve controlled to the closed side is held fully open in order to immediately stop the TRC. 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, similarly to the above-described embodiment, if a specific cylinder is deactivated in accordance with an increase in engine torque, it is possible to suppress a rapid increase in torque at this time.

In the throttle control device shown in FIG. 3, during cruise control traveling, the diaphragm actuator 49 rotates the guard lever 45 in the opening direction so that the DC motor 31 can throttle the throttle lever even if the accelerator is not operated. The valve 5 is rotationally controlled. Further, the throttle valve opening during and after warm-up during idling is controlled by the thermowax 50 and the operating rod 50a.

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 to execute cruise control and idling control under normal conditions is shown in FIG.
4 shows. FIG. 24 schematically shows the configuration of a throttle control device equipped with an electromagnetic clutch, and the principle of operation around the throttle valve as shown in FIG. In this figure, the upper side is the opening direction of the throttle valve 5, and the lower side is the closing direction.

In the present embodiment shown in FIG. 24, the accelerator opening sensor 47 of the embodiment shown in FIG. 3 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. The operation of the throttle control device will be described below. Normally, the energization of the clutch coil 80a of the electromagnetic clutch 80 is cut off. When the driver operates the accelerator pedal 44, the guard position sensor 48 outputs a signal θmg corresponding to the accelerator operation amount, 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, the clutch coil 80a of the electromagnetic clutch 80 is energized and the driven gear 28 and the throttle shaft 23 are directly connected. This allows
The throttle valve 5 is opened / closed by the DC motor 31. In the embodiment shown in FIG. 24, the guard lever 45
A guard stopper 90 is provided on the closing direction side of the throttle valve 5 for restricting further rotation of the closing side. The throttle valve opening corresponding to the guard stopper 90 is a fully closed position stopper 26 that indicates the fully closed position of the throttle valve 5.
The opening is set to be slightly larger than the opening.
As a result, when the throttle valve 5 is at 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 within the opening range corresponding to the position of the guard stopper 90 from the fully closed position. Even if 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 the opening and closing of the passage 100 is provided. This air valve 1
10 opens so that the bypass air amount increases when the engine is cold, and closes after the end of warming up to reduce the bypass air amount. After warming 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 with the throttle valve 5 and whose idle speed is controlled by the throttle valve 5 even in the cold state, the throttle valve 5 corresponds to a desired idle speed even after warming up due to a failure of the DC motor 31, the control device 61, or the like. There is a possibility that a problem may occur in which the engine speed is abnormally increased by keeping the engine open when the opening is exceeded. However, by providing the bypass passage 100 as described above,
This kind of trouble does not occur.

Also in this throttle control device, various fail judgments described in the embodiment of FIG. 3 are performed,
When it is determined that an abnormality in the throttle control system or a valve block has occurred, the fail-safe processing corresponding to this abnormality is executed in the same manner as in the embodiment of FIG. 3, and the cylinder number control and the estimated torque calculation are performed. However, in the electromagnetic clutch 80 shown in FIG. 24, the clutch is not reliably released when the clutch coil 80a is switched from the energized state to the non-energized state, 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-mentioned clutch lock occurs, it is necessary to reliably detect this abnormality. The clutch lock detection process will be described below. The clutch lock detection process is performed when the cruise control is released. In the cruise control, when the brake is depressed, that is, when the brake signal is turned on, as shown in FIG. 25A, the electromagnetic clutch 80 releases the connected state between the driven gear 28 and the throttle valve 5. Then, the clutch signal to the clutch coil 80a is turned off (FIG. 25 (b)). Here, when the brake pedal is depressed, it may be considered that the accelerator depression amount is almost zero. Therefore, the guard lever 45, the stopper lever 24,
The throttle shaft 23 and the like try to rotate in the closing direction by the urging force of the spring 46. Therefore, FIG.
As shown by the solid line in FIG.
Approaches a value corresponding to the position of the guard stopper 90. Therefore, when this cruise control is released, the driven gear 2
8 is held at that position for a predetermined time (KC1), the throttle opening command value θcmd is output to the DC motor 31 as indicated by the broken line in FIG.
8 is also set to the position of the fully closed position stopper 26. Then, if the clutch is surely disengaged, the driven gear 28 becomes the position of the fully closed position stopper 26 after the predetermined time, and the output value θth of the throttle opening sensor 34 attached to the driven gear 28 is as shown in FIG. (C) It becomes like the one-dot chain line.

On the other hand, if the clutch is locked, the guard lever 4 can be operated even after the cruise control is released.
5, the stopper lever 24, the throttle shaft 23, etc. are held in the same positions. Then, after the predetermined time,
When the driven gear 28 is rotated in the closing direction, the driven gear 28 is rotated accordingly, so that θmg coincides with θcmd as shown by the solid line in FIG.

Therefore, 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 the clutch is locked. Hereinafter, the clutch lock detection process when the cruise control is released will be described with reference to the flowchart shown in FIG. In addition,
This clutch lock detection process is performed by the process shown in FIG.
6 is incorporated into one of the plurality of fail judgment processes in the fail judgment process routine of FIG. 6 executed in step S1 of the throttle control routine.

When the clutch lock detection routine is called in the fail judgment routine shown in FIG.
It transfers to step S201 of FIG. Step S20
At 1, it is determined whether or not the clutch lock determination flag XFCLT indicating the occurrence of clutch lock has already been set. When the determination flag XFCLT is set, this processing is ended as it is.

On the other hand, if the determination flag XFCLT is not set in step S201, the process proceeds to step S202, and in the following steps S202 to 206, a predetermined time KC1 is delayed from the time when the cruise control is released,
Perform processing to close θcmd. That is, in step S202, it is determined whether the clutch signal is changed from ON to OFF and the cruise control is released. If it is determined that the clutch signal has changed from ON to OFF, the counter CCLT is set to zero in step S203. If not, step S
Increment the counter CCLT at 204 (CCLT
= CCLT + 1). As a result, the counter CCLT is counted up from the time when the clutch signal is turned off.

Then, in step S205, it is determined whether or not the count value of the counter CCLT is smaller than the predetermined time KC1. If the counter value CCLT is smaller than KC1, the process proceeds to step S206, and if not, this process ends. Then, 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 cruise control was released, step S2
At 06, the current θcmdi is made the same as the previous θcmdi-1.
Then, in step S208, it is determined whether or not θmg is smaller than θcmd. If θmg is smaller than θcmd, the process proceeds to step S210, and if not, the process proceeds to step S209. Then, in step S209, the counter CCLTF is incremented (CCLTF
= CCLTF + 1), and the process proceeds to step S211. On the other hand, in step S210, the counter CCLTF is set to zero, and the process proceeds to step S211. by this,
It is possible to detect how long the state in which the clutch lock abnormality occurs and the values of θmg and θcmd are the same is continued.

Then, in a step S211, it is determined whether or not the counter CCLTF is smaller than the predetermined time KCF. When it is determined that the counter CCLTF is smaller than the predetermined time KCF, the present process is ended as it is, otherwise the clutch lock determination flag XFCLT is set in step S212, and the present process is ended. Then, this process is terminated 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 of FIG. 5, the warning lamp is turned on and the power supply to the DC motor 31 is stopped. 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.
In S5, the throttle opening command value θcmd for the normal throttle control is set, θcmd is converted to Vcmd, and this Vcmd is output.

Thus, the clutch lock of the electromagnetic clutch 80 can be determined when the cruise control is released. Further, the clutch lock detection of the electromagnetic clutch 80 may be performed not when the cruise control is released as described above but when the engine is started, that is, when the ignition switch (hereinafter referred to as IGSW) is turned on. That is, as shown in FIG.
27 (b) and 27 when the GSW is turned on.
As shown in (c), the output value θcmd to the DC motor 31
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 period, θmg and θcmd are compared. Here, if the clutch lock is not generated, the throttle valve 5 is at the position of the guard stopper 90.
As shown in FIG. 27 (b), θmg <θcmd. On the other hand, if the clutch is locked, then θmg = θcmd as shown in FIG. 27 (c). Then, when the state of θmg = θcmd continues for a predetermined time (KCF), it is determined to be locked.

FIG. 28 shows the clutch lock detection processing by this processing. Note that this process is the same as that of FIG.
The process is almost the same as the process shown in FIG. Step S2
At 22, it is determined whether the IGSW is turned from OFF to ON, and if it is determined that the IGSW is turned from OFF to ON, the process proceeds to step S203, and if not, step S204.
Go to. As a result, the count up from the time when the IWSW is turned on.

In step S225, it is determined whether the count value of the counter CCLT is smaller than the predetermined time KC2. If the counter value CCLT is smaller than KC1, the process proceeds to step S226, and if not, this process ends. Then, in step S226, θ
Hold cmd as the above KMG. Next, step S2
At 08, by comparing θmg and θcmd (= KMG), it is possible to detect whether or not the clutch is locked.

Further, the clutch lock detection processing shown in FIG. 28 described above is executed at the start of deceleration fuel cut which is normally 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 no matter how the throttle valve 5 is driven during deceleration fuel cut, the behavior of the engine is not affected. Hereinafter, the clutch lock detection process at the time of deceleration fuel cut will be described with reference to FIG.
Indicate. Note that this processing is almost the same as the processing of FIG. 28, and the different point is step S232, and therefore the description of the other processing is omitted.

In step S232, it is determined whether or not the deceleration fuel cut flag XDFC is set from 0 to 1. This flag XDFC is normally in the accelerator pedal fully closed position, and the engine speed is a predetermined speed (for example,
It is set to be set at 1500 rpm). Then, if it is determined that the XDFC is set, the process proceeds to step S203, and if not, the counter CCLT is incremented (CCLT = CCLT +
1) Do. As a result, the count-up is performed from the time when the deceleration fuel cut is executed. In addition, step S22
At 6, θcmd is held in the KMG. Then, in step S208, by comparing θmg and θcmd,
It is possible to detect whether or not the clutch is locked.

Next, as another embodiment, the fuel cut cylinder number Nfc may be set based on the vehicle speed or the engine speed. A schematic configuration diagram of this embodiment is shown in FIG. FIG. 30 is a schematic block diagram of the vehicle speed sensor 1 shown in FIG.
21 and the shift position sensor 122 are added. The other configuration is similar to that of FIG.

FIG. 31 shows a flowchart executed by the CPU 62 in place of FIG. 17 in such a configuration, and description will be given below according to this flowchart. In this flowchart, the fail flag XFAIL1 is set to "0" as the initialization process when the IGSW is turned on.
And Further, this flowchart is executed every 720 degrees at the crank angle of the internal combustion engine 1.

When this processing is executed, step S30
1, the fuel injection amount required by the current 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, Set the pulse width corresponding to the injection quantity. Next, in step S302, the fail flag XF
It is determined whether AIL1 is "1". If it is not "1", the process proceeds to step S303 to set the fuel cut cylinder number Nfc to "0", and the process proceeds to step S307.

If the fail flag XFAIL1 is "1" in step S302, the process proceeds to step S304, and it is determined whether the driving force of the engine is currently transmitted to the driving wheels. In the case of an automatic transmission (AT) vehicle, this determines 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 transmitted, the process proceeds to step S305.

In step S306, the number Nfc of fuel cut cylinders corresponding to the vehicle speed detected by the vehicle speed sensor 121 is set from the map shown in FIG. That is, the slower the vehicle speed, the larger the number of fuel cut cylinders Nfc. Further, in step S305, the number Nfc of fuel cut cylinders is set from the map shown in FIG. That is, the higher the engine speed, the larger the fuel cut cylinder number Nfc.
When the fuel cut cylinder number Nfc is set in step S305 and step 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 injector drive circuit 65 energizes a number of injectors 7 corresponding to the number Nfc of fuel cut cylinders to inject fuel, and these cylinders operate.

By executing the above processing, when the driving force is transmitted, the number Nfc of fuel cut cylinders is set according to the vehicle speed. Specifically, the fuel cut cylinder number Nfc is increased as the vehicle speed decreases. Thus, 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, the number of fuel cut cylinders Nfc is set to decrease as the vehicle speed increases, so that drivability is prevented from being deteriorated.

When the driving force is not transmitted,
The fuel cut cylinder number Nfc is set according to the engine speed. Specifically, the fuel cut cylinder number Nfc is set to increase as the engine speed increases. As a result, it is possible to prevent the engine speed from increasing when the driving force of the engine is not transmitted to the wheels when the gear shift position is in the neutral state. Further, the excessive engine rotation 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 the failure is detected. And then I
Since the fail flag XFAIL1 is reset to "0" when the GSW is turned on, the fuel injection process in the normal state is performed if the normal state is restored, and the fail flag XFAIL1 is set to "reset" if the abnormal state is still continued. Therefore, the fuel cut is executed, and the fuel injection process associated therewith is executed.

32 and 33 in the above embodiment.
A hysteresis characteristic may be given to the condition for switching the number of fuel cut cylinders Nfc in the map shown in FIG.

[0116]

As described above, according to the throttle control device for an internal combustion engine of the first aspect of the present invention, when an abnormality occurs in the throttle control system, a specific cylinder of the internal combustion engine is increased according to the increase in the engine torque. Is paused. Therefore, an increase in engine torque contrary to the driver's intention when the throttle opening changes to the open side due to the occurrence of an abnormality is reliably suppressed. Therefore, the driver can continue driving without re-adjusting the accelerator operation amount, and the feeling of throttle operation can be greatly improved.

According to the throttle control device for an internal combustion engine of the second aspect of the present invention, when the driver performs an accelerator return operation after an abnormality has occurred in the throttle control system, all cylinders of the internal combustion engine are activated, so It is possible to prevent the vibration from increasing due to the deactivation of the cylinders, and to continue traveling of the vehicle without impairing the comfort inside the vehicle.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram conceptually showing the content of one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a throttle control device for an internal combustion engine that is an embodiment of the present invention.

FIG. 3 is a perspective view showing the vicinity of 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 an explanatory diagram schematically showing an operating 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. 5 is a flowchart showing a throttle control routine executed by a CPU of a throttle control device for an internal combustion engine which is an embodiment of the present invention.

FIG. 6 is a flowchart showing a fail determination routine executed by a CPU of a throttle control device for an internal combustion engine that is an embodiment of the present invention.

FIG. 7 is a flowchart showing a first throttle control system abnormality determination routine executed by a CPU of a throttle control device for an internal combustion engine which is an embodiment of the present invention.

FIG. 8 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 which is an embodiment of the present invention.

FIG. 9 is a flow chart showing a second throttle control system abnormality determination routine executed by the CPU of the throttle control device for an internal combustion engine which is an embodiment of the present invention.

FIG. 10 is a flowchart showing an accelerator interlocking mechanism abnormality determination routine executed by a CPU of a throttle control device for an internal combustion engine that is an embodiment of the present invention.

FIG. 11 is a flowchart showing a spring breakage determination routine executed by a CPU of a throttle control device for an internal combustion engine that is an embodiment of the present invention.

FIG. 12 is a flowchart showing a valve lock determination routine executed by a CPU of a throttle control device for an internal combustion engine which is an embodiment of the present invention.

FIG. 13 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 that is an embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a map for determining a throttle command voltage in a throttle control device for an internal combustion engine that is an embodiment of the present invention.

FIG. 15 is an explanatory diagram showing a map for determining a throttle opening command value during limp home control in a throttle control device for an internal combustion engine which is an embodiment of the present invention.

FIG. 16 is a time chart when an abnormality occurs in the throttle control system in the throttle control device for the internal combustion engine which is one embodiment of the present invention.

FIG. 17 is a flowchart showing a fuel injection control routine executed by a CPU of a throttle control device for an internal combustion engine which is an embodiment of the present invention.

FIG. 18 is a flowchart showing a fuel cut flag setting routine executed by the CPU of the throttle control device for an internal combustion engine which is an embodiment of the present invention.

FIG. 19 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 which is an embodiment of the present invention.

FIG. 20 is an explanatory diagram showing a map for determining an estimated torque in a throttle control device for an internal combustion engine that is an embodiment of the present invention.

FIG. 21 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 which is an embodiment of the present invention.

FIG. 22 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 the internal combustion engine which is one embodiment of the present invention.

FIG. 23 is a schematic configuration diagram showing a conventional throttle control device for an internal combustion engine.

FIG. 24 is an explanatory diagram schematically showing the operating 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. 25 is a time chart of each signal when the cruise control is released.

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

FIG. 27 is a time chart of each signal when the ignition switch is ON.

FIG. 28 is a flowchart showing a clutch lock detection routine.

FIG. 29 is a flowchart showing a clutch lock detection routine.

FIG. 30 is a schematic configuration diagram showing a throttle control device for an internal combustion engine of another embodiment.

FIG. 31 is a flowchart showing processing executed by a CPU in another embodiment.

FIG. 32 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. 33 is an explanatory diagram showing a map for determining the number of fuel cut cylinders from the engine speed in a throttle control device for an internal combustion engine in another embodiment.

[Explanation of symbols]

 M1 internal combustion engine M2 throttle valve M3 throttle drive means M4 accelerator interlocking means M5 engine torque estimating means M6 cylinder deactivation number setting means M7 cylinder deactivation control means 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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsuo Hara 1-1, Showa-cho, Kariya city, Aichi prefecture

Claims (5)

[Claims] 1. A throttle driving means for controlling the opening of a throttle valve of an internal combustion engine based on a predetermined throttle opening command value is provided, and mechanically interlocked with accelerator operation on the opening side of the throttle driving means. A throttle control device for an internal combustion engine, comprising: an accelerator interlocking means for opening and closing a throttle valve, stopping throttle control by the throttle drive means when an abnormality occurs in the throttle control system, and opening and closing the throttle valve by the accelerator interlocking means. An engine torque estimating means for estimating an engine torque when an abnormality occurs in the throttle control system and an engine torque after the throttle opening changes to the open side due to the occurrence of an abnormality, and an engine torque estimated by the engine torque estimating means. Based on this, calculate the increase in engine torque before and after the occurrence of an abnormality Then, the cylinder deactivation number setting means for setting the cylinder deactivation number for suspending the operation of all cylinders of the internal combustion engine, and the cylinder deactivation number set by the cylinder deactivation number setting means when an abnormality occurs in the throttle control system. A throttle control device for an internal combustion engine, comprising: a cylinder deactivation control means for deactivating a specific cylinder correspondingly. 2. An accelerator return operation detecting means for detecting an accelerator return operation after an abnormality occurs in the throttle control system, and a cylinder deactivation control means when the accelerator return operation is detected by the accelerator return operation detecting means. The throttle control device for an internal combustion engine according to claim 1, further comprising a cylinder deactivation ending means for terminating the cylinder deactivation control. 3. A throttle control device for an internal combustion engine for driving drive wheels of a vehicle, comprising: a throttle drive means for controlling an opening of a throttle valve of the internal combustion engine based on a predetermined throttle opening command value; and the throttle drive means. From the open side, the accelerator interlocking mechanism that mechanically interlocks with the accelerator operation to open and close the throttle valve, and when the throttle control system malfunctions, stop the throttle control by the throttle driving means and use the accelerator interlocking mechanism to open the throttle valve. Based on the throttle control stopping means for driving to open / close, and the torque generated in the drive wheels, the larger the torque, the larger the number of cylinders to be stopped for suspending the operation of all the cylinders of the internal combustion engine when an abnormality occurs The cylinder deactivation number setting means and the cylinder deactivation number setting means set when an abnormality occurs in the throttle control system. Throttle control apparatus for an internal combustion engine, characterized in that it comprises a cylinder deactivation control means for halting the particular cylinder corresponding to the cylinder deactivation rate. 4. The cylinder deactivation number setting means includes means for setting the torque generated in the drive wheels to be greater as the vehicle speed is slower, and to set the number of cylinder deactivation to be greater as the vehicle speed is slower. The throttle control device for an internal combustion engine according to claim 3. 5. A torque transmission determining means for determining whether torque generated in an internal combustion engine is transmitted to the drive wheels, wherein the cylinder deactivation number setting means further applies torque to the drive wheels by the torque transmission determining means. 5. The throttle control device for an internal combustion engine according to claim 4, further comprising means for setting such that, when it is determined that the cylinder is not transmitted, the cylinder deactivation number increases as the rotation speed increases.