JP2001065368A - Throttle control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a throttle control device for an internal combustion engine difficult to receive an influence by noise of a detection output of an accelerator sensor when abnormality is generated. SOLUTION: Since a target throttle opening of a throttle valve is changed by stages relating to an accelerator opening detected by a first/second accelerator sensor 53, 54, even when a noise is generated to overlap with a detection output of the accelerator sensor, fine changing of the target throttle opening of the throttle valve 10 is eliminated, consequently an output of an engine is prevented from changing by the noise.

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 which opens and closes a throttle valve of an internal combustion engine mounted on a vehicle by an actuator and adjusts an opening of the throttle valve.

[0002]

2. Description of the Related Art As is well known, a throttle valve provided in an intake passage of an internal combustion engine is mechanically connected to an accelerator pedal operated by a driver through a wire or the like. It is uniquely determined according to the amount of depression. On the other hand, in recent years, a system in which the throttle valve is opened and closed using an actuator such as a motor based on the operating state of the internal combustion engine, that is, a so-called electronic throttle control system has been adopted.

In this electronic throttle control system, a sensor for detecting an operation amount of an accelerator pedal is provided, and based on an operation amount of the accelerator pedal detected by the sensor and an operation state of the internal combustion engine. A target throttle opening is calculated, and the throttle valve is opened and closed by an actuator such that the opening of the throttle valve becomes the target throttle opening.

Incidentally, the electronic throttle control system has a double control system for improving safety, and at least two sensors for detecting the operation amount of the accelerator pedal are provided, and one of the sensors has failed. Sometimes the detection output of the other sensor is used for opening and closing control of the throttle valve.

For example, in the device described in Japanese Patent Application Laid-Open No. 10-299513, when one of the two accelerator sensors fails, the normal accelerator sensor is selected to further secure sufficient safety. For this reason, the detection output of the normal accelerator sensor is reduced by half and used for opening and closing control of the throttle valve.

[0006]

However, in the above-mentioned conventional apparatus, when noise is included in the detection output of the selected normal accelerator sensor, the operation amount of the accelerator pedal changes according to the noise. As a result, there is a problem that the opening of the throttle valve changes and the output of the internal combustion engine fluctuates carelessly.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described conventional problems, and has as its object to provide a throttle control device for an internal combustion engine which is hardly affected by noise in the detection output of an accelerator sensor when an abnormality occurs. I do.

[0008]

In order to solve the above-mentioned conventional problems, the present invention is to open and close a throttle valve of an internal combustion engine mounted on a vehicle by an actuator, and to detect an accelerator operation amount by detecting an opening degree of the throttle valve. A throttle control device for an internal combustion engine that adjusts the throttle valve in accordance with an accelerator operation amount detected by the means, wherein the throttle valve can be opened and closed when an abnormality is detected in the throttle control device. And an abnormality determining means for determining an abnormal state in which a signal is output from the accelerator operation amount detecting means, and a signal from the accelerator operation amount detecting means, wherein a predetermined constant value which is different for each of a plurality of predetermined operation areas. And a signal processing means for converting the signal into a step-like signal in accordance with the accelerator operation amount; When the condition is determined, and a control means for controlling the opening degree of the throttle valve based on a signal from the signal processing means.

According to the present invention, when the throttle control device is abnormal, the signal from the accelerator operation amount detecting means is converted into a different constant value for each of a plurality of predetermined operation areas, and converted into the accelerator operation amount. A stepped signal corresponding to the stepped signal is used, and the opening of the throttle valve is controlled based on the stepped signal. Therefore, even if noise is superimposed on the signal from the accelerator operation amount detecting means, this signal is kept at a certain value. As a result, the opening degree of the throttle valve does not change in response to the noise, so that the throttle valve is not easily affected by the noise.

In one embodiment, the constant value of the signal processing means is set smaller than a value detected by the accelerator operation amount detecting means when the abnormal state is not determined by the abnormality determining means. I have. When the constant value is set to a small value in this manner, the throttle opening at the time of the abnormality becomes small, thereby preventing overrun of the internal combustion engine and notifying the driver of the occurrence of abnormality due to a decrease in the output of the internal combustion engine. . Further, even when the signal from the accelerator operation amount detecting means at the time of an abnormality is output larger than the actual value due to superposition of noise or the like, overrun of the internal combustion engine can be prevented.

In one embodiment, the signal from the accelerator operation amount detecting means used in the signal processing means is used with the rate of change of the signal being limited to within a predetermined value. Also in this case, when the signal from the accelerator operation amount detecting means at the time of abnormality is output larger than the actual value due to superposition of noise or the like, overrun of the internal combustion engine can be prevented.

In one embodiment, the signal from the accelerator operation amount detecting means used in the signal processing means is used by limiting the magnitude of the signal within a predetermined value. Thus, overrun of the internal combustion engine can be reliably prevented.

[0013]

1 and 2 show an embodiment of a throttle control device for an internal combustion engine according to the present invention.

First, a schematic configuration of an internal combustion engine to which the throttle control device of the embodiment is applied and peripheral devices thereof will be described with reference to FIG.

Referring to FIG. 1, an internal combustion engine (vehicle engine)
1 is configured as, for example, an in-line four-cylinder four-cycle engine. An air cleaner (not shown) is provided upstream of the intake passage 2 of the engine 1, and a throttle valve 10 is provided downstream of the air cleaner. This throttle valve 10 is provided with an electronic control unit (EC
The throttle valve 10 is opened and closed by a motor 11 whose drive is controlled through U) 20, and the amount of air supplied to the engine 1 is adjusted according to the opening of the throttle valve 10.

The throttle valve 10 is provided with a throttle opening sensor 12 as a peripheral device, and the opening of the throttle valve 10 is detected through the throttle opening sensor 12. This detection signal is taken into the ECU 20 as the throttle opening signal TA.

The throttle valve 10 in the intake passage 2
An intake pressure sensor 13 for detecting the amount of intake air (intake pressure) to the engine 1 is provided downstream of the engine. Intake air amount (intake pressure) detected by the intake pressure sensor 13
Is taken into the ECU 20 as the intake pressure signal PM.

Further, the intake passage 2 is connected to each cylinder of the engine 1 via an intake manifold 5, and air sucked from the intake passage 2 and adjusted by the throttle valve 10 is supplied to the intake manifold 5. , And is distributed and supplied to each cylinder of the engine 1.

The intake manifold 5 has an injector 5 serving as a fuel injection valve corresponding to each cylinder.
a, 5b, 5c and 5d are provided. The fuel injected and supplied through the injectors 5a to 5d is mixed with the adjusted and distributed intake air from the intake passage 2 and supplied to each cylinder of the engine 1.

In each cylinder of the engine 1, the supplied air-fuel mixture explodes and burns in each combustion chamber based on the ignition of the ignition plugs 6a to 6d, and a driving force is applied to a crankshaft (not shown). The exhaust gas after the combustion is discharged to the exhaust passage 3, further purified through the catalyst 31, and then discharged to the outside.

A crank angle sensor 24 for detecting the rotation angle is provided near the crankshaft. From the crank angle sensor 24, a predetermined angle (for example, 30 degrees) of the rotation angle (crank angle) of the crank shaft is
A pulse signal is output for each rotation angle (°), and the output pulse signal is taken into the ECU 20 as a rotation speed signal NE corresponding to the rotation speed (rotation speed) of the engine 1.

A camshaft (not shown), which is drivingly connected to the crankshaft, is provided with a cam angle sensor 25 near the camshaft. The cam angle sensor 25 is normally used as a cylinder discrimination sensor, and outputs an appropriate pulse signal corresponding to, for example, the compression top dead center (TDC) of the first cylinder # 1. This output pulse signal is
Similarly, the ECU 2 serves as a cam angle signal (cylinder discrimination signal) CA.
It is taken into 0.

The body of the engine 1 is provided with a water temperature sensor 26 for detecting the temperature of the cooling water flowing through the water jacket. The detection signal from the water temperature sensor 26 is taken into the ECU 20 as a water temperature signal THW, and is subjected to various controls as a parameter indicating the engine temperature of the ethidine 1.

On the other hand, an accelerator pedal 51 is provided in the cabin of a vehicle (not shown), and its operation amount (stepping amount) is controlled.
Is detected by the first and second accelerator sensors 53 and 54. The first accelerator sensor 53 has a resistance band 53a and a slider 53b that slides on the resistance band 53a, and the slider 53b moves on the resistance band 53a in conjunction with the operation of the accelerator pedal 51. Slide. Similarly, the second accelerator sensor 54 has a resistance band 54a and a slider 54b that slides on the resistance band 54a.
Is operated in response to the operation of the accelerator pedal 51,
Slide on top.

The ECU 20 supplies a reference voltage Vc (for example, 5.0
V) and the ground potential E (for example, 0 V) are applied to the resistance bands 53a, 54a of the first and second accelerator sensors 53, 54.

The sliders 53b, 53b of the first and second accelerator sensors 53, 54 are linked with the operation of the accelerator pedal 51.
54b slides on the respective resistance bands 53a, 54a,
Accelerator opening signals VPa1 and VPa2 corresponding to the positions of these sliders 53b and 54b are output from the respective sliders 53b and 54b.
b and 54b are output to the ECU 20. ECU 20
Selects, for example, the smaller one of the accelerator opening signals VPa1 and VPa2, and calculates the operation amount of the accelerator pedal 51 (accelerator opening PACAL) based on the selected opening signal.

A brake switch 57 is provided on the brake pedal 56 which is operated during braking of the automobile. When the brake pedal 56 is operated, the brake switch 57 is turned on. The ECU 20 determines whether the brake pedal 56 is operated by turning on and off the brake switch 57.

The ECU 20 includes, for example, a microcomputer, and receives the intake pressure signal PM.
The injectors 5a to 5d are controlled based on the rotation speed signal NE, the water temperature signal THW and the like, and the throttle opening signal TA and the accelerator opening signal VPa1,
The ECU 20 controls the opening and closing of the throttle valve 10 based on VPa2, the water temperature signal THW, and the like.
The ignition timing (ignition timing) for igniting the air-fuel mixture introduced into each combustion chamber also depends on the rotation speed signal NE and the intake pressure signal P.
M, and outputs a signal (ignition signal) indicating the ignition timing to the igniter 61. The igniter 61 is a device that converts the input ignition signal into electric power capable of driving the ignition of the ignition plugs 6a, 6b, 6c, 6d by an ignition coil 62 provided therein. As a result, the air-fuel mixture supplied into each cylinder of the engine 1 is ignited at the calculated ignition timing, and explodes and burns.

On the other hand, the engine 1 is connected to an automatic transmission 52 for switching the shift mode of the vehicle. The automatic transmission 52 is provided with a shift position sensor 22 for detecting the shift position (shift position). The shift position sensor 22 is mainly used for the automatic transmission 5.
2 is in the N (neutral) range,
Alternatively, it is detected whether the vehicle is in the D (drive) range, and the detected content is used as shift position information by the ECU.
20.

Further, a vehicle speed sensor 23 is provided near the axle of the vehicle (not shown), and the rotational speed of the axle, that is, the speed of the vehicle is detected by the vehicle speed sensor 23. This detection signal is taken into the ECU 20 as a vehicle speed signal.

In the present embodiment, the shift position information and the vehicle speed signal are also referred to when adjusting the engine output to be described later, particularly when learning the adjustment amount.

Next, the above-described throttle valve 10 and its peripheral structure will be described in detail with reference to FIG.

In the throttle control device of this embodiment, as shown in FIG. The power from the motor 11 is transmitted to the throttle valve 10 and the power is also directly transmitted to the throttle opening sensor 12 so that the opening of the throttle valve 10 is directly reflected on the throttle opening sensor 12. Has become. As described above, the motor 11 is the ECU 2 not shown in FIG.
0 (FIG. 1) controls the drive. On the other hand, the throttle valve 10 is provided with an auxiliary mechanism 40 using a spring mechanism, and an abnormality occurs in which the throttle valve 10 cannot be driven by the motor 11. At this time, that is, at the time of a throttle failure, the throttle valve 10 is fixed at a predetermined opening through the auxiliary mechanism 40.

That is, in the auxiliary mechanism 40, the valve lever 44 connected to the throttle valve 10
A retraction travel spring 42 for urging the throttle valve 10 in the valve opening direction with an urging force F2 is provided, and a valve return lever 43 which can move independently of the valve lever 44 has a valve lever with an urging force F1. A valve return spring 41 for urging the valve 44 in the valve closing direction of the throttle valve 10 is provided.

Here, the valve return spring 4
The urging force F1 of 1 and the urging force F2 of the evacuation travel spring 42 are set to have a relationship of F1> F2. However, since the intermediate stopper 46 is provided for the valve return lever 43, When the motor 11 is not energized, such as during a throttle failure, the positional relationship between the valve return lever 43 and the valve lever 44, that is, the opening of the throttle valve 10, is fixed in the manner shown in FIG. This fixed opening of the throttle valve 10 is the above-mentioned predetermined opening, and is usually set to an opening slightly more open than the opening of the throttle valve 10 required during idling operation through the position setting of the intermediate stopper 46. Is set.

When the throttle valve 10 is normal,
When the valve 10 is driven in the valve opening direction through the motor 11, the valve lever 44 and the valve return lever 4 are pressed against the urging force F 1 of the valve return spring 41.
2, the throttle valve 10 is fully opened when the valve return lever 43 comes into contact with the fully opened stopper 47 in the direction of arrow F3 in FIG.

When the throttle valve 10 is driven normally in the valve closing direction through the motor 11 when the throttle valve 10 is normal, the valve lever 44 is moved in FIG. The throttle valve 10 is fully closed when it is pushed up in the direction of arrow F4 and the valve lever 44 contacts the fully closed stopper 45.

When a throttle failure occurs, the opening of the throttle valve 10 is fixed at the above-mentioned predetermined opening, so that the limp-home running performance is ensured. Further, during idling operation, overrun and the like are prevented by performing reduced cylinder operation of the engine 1 or adjusting engine output (engine output) such as air-fuel ratio correction and ignition timing correction.

If the engine output is adjusted without taking into account the difference in engine resistance (friction) between the cold operation and the warm operation, a stall or overrun may occur during idle operation during throttle failure. is there. That is, if the engine output is adjusted based on the warm operation of the engine 1, the engine 1 may be stalled during the cold operation of the engine 1, and the engine output may be adjusted so as not to stall during the cold operation. Is performed on the basis of the cold operation of the engine 1,
During the warm operation of the engine 1, overrun may be caused. For this reason, it is preferable that the control be performed separately between the cold operation and the warm operation.

The first and second accelerator sensors 53, 53
When at least one of the failures 54 occurs, the detection signals of the first and second accelerator sensors 53 and 54 cannot be fully relied on, but the driver's intention to drive is identified as much as possible while ensuring safety. It is preferable to control the opening degree of the throttle valve 10 while reflecting the change.

Therefore, in the present embodiment, processing is performed according to flowcharts shown in FIGS. 3, 5, 7, 8, 11, 12, 13, 14, 15, and 16. Thus, appropriate throttle control is performed according to various states of the throttle control device.

Hereinafter, the details of the engine output adjustment processing will be described with reference to FIGS.

First, a routine for determining an initial value of the engine output level in the engine output adjustment processing will be specifically described with reference to FIGS. In addition,
The engine output adjustment processing including this routine is executed as a pre-processing of a well-known engine control main routine for controlling the overall operation of the engine 1. For example, the crankshaft detection through the crank angle sensor 24 is performed. EC as interrupt processing for each predetermined angle
Performed by U20.

Now, in the engine output level initial value determination routine shown in FIG. 3, the ECU 20 determines whether or not the throttle control device abnormality flag is set first after the engine is started (step S101). Here, the throttle control device abnormality flag is a flag that is set when an abnormality occurs in the throttle control device itself, and a mechanical abnormality or an electric circuit abnormality occurs by a separate routine (not shown). It is set on the condition that Note that this throttle control device abnormality flag is
It is set in a volatile memory or register inside the ECU 20, and is reset once when the operation of the engine 1 is stopped.

Only when it is determined that such a throttle control device abnormality flag is set first (step S101, Yes), the process proceeds to step S102, and the process of determining the engine output level learning initial value is performed.

In step S102, the ECU
20 reads the value of the engine coolant temperature THW and the map A shown in FIG. 4 and determines an engine output level learning initial value corresponding to the value of the engine coolant temperature THW based on the map A. In addition, this map A uses ECU
20 is stored in advance in a nonvolatile memory inside.

After the initial value of the engine output level learning is thus determined, the routine proceeds to an engine output level learning routine shown in FIGS.

On the other hand, if it is determined that the throttle control device abnormality flag has already been set or has not been set (normal) (step S101, N).
o), the routine is skipped, and the process directly proceeds to the engine output level learning routine shown in FIGS.

Next, a routine for learning the engine output level in the engine output adjustment processing will be specifically described with reference to FIGS.

In the engine output level learning routine shown in FIG. 5, the ECU 20 first reads the throttle control device abnormality flag and the post-start determination flag, and performs a logical product (AND) of the fact that these flags are set together. It is determined whether or not the condition is satisfied (step S201), where the throttle control device abnormality flag is described above, and the post-start determination flag is that the starter (not shown) of the engine 1 is turned off. ,
Alternatively, the flag is set based on, for example, that the engine 1 has reached autonomous operation.

When it is determined that the logical product (AND) condition is not satisfied, that is, when the throttle control device is normal or the engine 1 is starting (No in step S201). , The ECU 20
After prohibiting fuel cut (F / C) for some cylinders (step S202), the routine proceeds to the well-known engine control main routine.

On the other hand, if it is determined that both the throttle control device abnormality flag and the after-start determination flag are set (step S201, Yes), the ECU
Step 20 determines whether there is a throttle failure, that is, an abnormality in which the throttle valve 10 cannot be driven by the motor 11 (step S203). For example, if another abnormality has occurred in the throttle valve control device instead of the throttle failure (step S203,
Yes), the ECU 20 shifts to the processing shown in FIGS. 11 to 16, and thereafter shifts to the well-known engine control main routine.

In the case of a throttle failure where the throttle valve 10 is fixed at a predetermined opening,
The output of the engine 1 is controlled as follows.

First, the ECU 20 calculates upper and lower limits for monitoring the number of revolutions during idling (step S).
204). In this step S204, the value of the engine coolant temperature THW, the shift position of the automatic transmission 52, and the map B shown in FIG. 6 are read, and based on the map B, the value of the engine coolant temperature THW and the shift Feedback (F) corresponding to the position information (N, D)
/ B) Reference upper limit rotational speed NEFBU and lower limit rotational speed N
The EFBD is calculated and determined. After the upper and lower limit rotational speeds NEFBU and NEFBD are determined, the ECU 20
It is determined whether the engine 1 is in an idle operation or a non-idle operation (step S205). Specifically, from the vehicle speed sensor 23, the crank angle sensor 24, and the first and second accelerator sensors 53 and 54, the vehicle speed, the degree of fluctuation of the engine speed, and the accelerator opening PACAL are obtained.
Is read, ・ The vehicle speed is not displayed. -Engine speed fluctuations are within a certain range. -The accelerator opening PACAL is an idle opening. A check is made as to whether the logical product (AND) condition is satisfied.

If it is determined that the logical product (AND) condition is not satisfied (step S20)
5, No), it is determined that the engine 1 is currently in the non-idle operation, and the process proceeds to an engine output level determination routine (FIG. 8) described later.

On the other hand, if it is determined that the logical product (AND) condition is satisfied (step S205, Y
es) Assuming that the engine 1 is currently idling, the process proceeds to the learning process of step S206 and the subsequent steps shown in FIG.

In this learning process, step S206
In S210 and S210, the engine speed NE is read, and the engine speed NE and the value in Step S2 are read.
A comparison is made with the F / B reference lower limit rotational speed NEFBD determined in 04.

That is, in step S206, it is checked whether or not the read engine speed NE is lower than the F / B reference lower limit engine speed NEFBD based on a comparison of NE <NEFBD.

As a result of this check, the engine speed NE
Is determined to be less than the F / B reference lower limit rotational speed NEFBD (step S206, Yes),
U20 increments a rise counter for rotation speed rise correction (step S207). And the ECU 20
Compares the increment counter value with a predetermined value set to execute correction (learning value update) (step S208). Thereafter, when the comparison condition in step S206 of the routine continues to be satisfied, the relationship of rising counter value> predetermined value is reached (step S208, Ye
s) The ECU 20 performs an engine output level-based learning value update process (step 209). This step S2
In step 09, the engine output level learning determined in step S102 is performed on the condition that the state where the engine speed NE is lower than the F / B reference lower limit engine speed NEFBD continues for a period corresponding to the predetermined value. The engine output level-based learning value, which is the initial value, is updated in a mode such as the engine output level-based learning value + 1.

On the other hand, on the condition that it is determined that the engine speed NE is not lower than the F / B reference lower limit engine speed NEFBD (step S206, No), the ECU 20 performs the above based on the comparison NE> NEFBU. The read engine speed NE is the F / B reference upper limit engine speed NEF.
It is checked whether or not it exceeds BU (step S
210).

As a result of this check, the engine speed NE
Is determined to exceed the F / B reference upper limit rotational speed NEFBU (step S210, Yes),
U20 increments the lowering counter for rotational speed lowering correction (step S211). And the ECU 20
Compares the incremented descending counter value with a predetermined value set for performing correction (learning value update) (step S212). Thereafter, when the comparison condition in the above step S210 of the routine is continuously satisfied, the relationship of descending counter value> predetermined value is reached (step S212, Ye
s), the ECU 20 performs an engine output level-based learning value update process (step S213). This step S
In 213, on the condition that the engine speed NE is continued over a period corresponding to the above-mentioned predetermined value, the engine output level-based learning value determined in the step S102 is changed to an engine output level-based learning value-1. Will be updated.

When the engine output level-based learning value has been updated in this way, the ECU 20 performs upper / lower limit guard processing such as 1 ≦ engine output level-based learning value ≦ 5 (step S21).
4) After clearing the up counter and the down counter (step S215), the process proceeds to an engine output level determination routine. Note that the above S206 and S2
If the comparison conditions at 10 are not satisfied, that is, if the engine speed NE is in the range of NEFBD ≦ NE ≦ NEFBU, the above-described step S215 is performed.
Then, the process proceeds to the engine output level determination routine.

Next, a routine for finally determining and reflecting the engine output level based on the learned base learning value will be specifically described with reference to FIG. In the engine output level determination routine shown in FIG.
In steps S301 and S304, the accelerator opening PACAL detected through the first and second accelerator sensors 53 and 54 is read. In step S301, based on a comparison such as PACAL <10 °, it is determined whether there is an acceleration request. In step S304, the degree of request when acceleration is requested is determined based on a comparison such as 10 ° ≦ PACAL <20 °.

If it is determined that the accelerator opening PACAL is less than 10 degrees (step S301, Ye
s) Assuming that there is no acceleration request, the ECU 20 proceeds to step S302, and determines the engine output level as engine output level = base learning value.

After the engine output level is determined in this way, in the next step S303, the ECU 20 applies upper and lower limit guards to the determined engine output level in the form of 1 ≦ engine output level ≦ 5. The process proceeds to S308.

The read accelerator pedal opening PAC
If it is determined that AL is equal to or more than 10 ° and less than 20 ° (step S304, Yes), the ECU 20
Indicates that although there is an acceleration request, the request degree is determined to be small, and the process proceeds to step S305 to determine the engine output level as engine output level = base learning value + 1.

In this case, the ECU 20 performs upper and lower limit guards on the determined engine output level in a manner such that 2 ≦ engine output level ≦ 5 (step S306), and proceeds to the process of step S308.

On the other hand, the read accelerator pedal opening PAC
If it is determined that AL is equal to or greater than 20 ° (No at Step S304), the ECU 20 determines that the degree of the acceleration request is large, and proceeds to Step S307, where the engine output level is set to 5 and the engine output level is set. Is fixedly determined. The engine output level of level “5” is the maximum level at the time of a throttle failure in the present embodiment, and in this case, the guard processing is not performed and step S30 is performed.
Then, the process proceeds to a step S8.

After the engine output levels are determined in this way, the map C shown in FIG. 9 is read in step S308, and based on the map C, the number of operating cylinders corresponding to the determined engine output levels is determined. And the ignition timing is determined. The determined number of operating cylinders and the determined ignition timing are reflected in the engine control main routine executed subsequently.

When the throttle valve 10 is fixed at a predetermined opening in accordance with the throttle failure (see FIG. 2), first, based on the engine temperature (engine water temperature THW) when the throttle failure is determined. The engine output level base value (learning initial value) is map A (Fig. 4).
Is determined through However, this base value is based on the number of rotations of the engine 1 during idling operation, and the number of rotations is a predetermined number of rotations corresponding to the engine temperature and the shift position of the automatic transmission defined by the map B (FIG. 6). While the feedback control is performed so as to fall within the range, the appropriate value is learned. For this reason, there are individual differences in the engine 1,
Even if the characteristics change over time, the base value of the engine output level determined through the map A is always maintained at an appropriate value.

When the accelerator pedal 51 is depressed during the limp-home operation of the vehicle as well as during idling of the engine 1, the accelerator pedal opening PACAL, which is the amount of the operation, and a base value corresponding to the same opening PACAL. The final engine output level is determined based on the base learning value). As a result, the engine 1 is set to an appropriate output level according to the situation, whether during idling or during limp-home operation.

According to the determined engine output levels "1" to "5", as shown in map C (FIG. 9), (a) corresponding to engine output level "1" Then, the engine 1 is operated with the number of operating cylinders of the engine 1 being “2”, that is, two cylinders are reduced. At the same time, the engine 1 is operated with the ignition timing retarded from the ignition timing in the normal control.
As shown in FIG. 10, the engine output also changes depending on the ignition timing. Here, the engine speed NE and the intake pressure P
M and is retarded by 25 ° CA (crank angle) from the normal ignition timing determined by M. (B) In response to the engine output level "2", the number of operating cylinders of the engine 1 is "3", that is, the engine 1 is operated with one cylinder reduced. At the same time, the ignition timing is delayed by 30 ° CA from the normal ignition timing. (C) Corresponding to the engine output level "3", the number of operating cylinders of the engine 1 is "4", that is, all cylinders are operated.
Also, in this case, the ignition timing is retarded by 30 ° CA from the normal ignition timing. (D) Corresponding to the engine output level "4", the engine 1 is operated in all cylinders as in (c). In addition, in this case, the ignition timing is set at 25 ° from the normal ignition timing.
It retards only by CA. (E) Corresponding to the engine output level "5", the engine 1 is operated in all cylinders as in (c) and (d) above. At the same time, the engine 1 is operated with the ignition timing set to the normal ignition timing. In such a manner, the operating conditions of the engine 1 are controlled. By controlling the operating conditions of the engine 1 in this manner, the engine output level "1"
The engine output is sequentially increased in accordance with the values ".about." 5. The operating conditions to be controlled are appropriately selected according to the engine temperature, thereby preventing stall of the engine 1 during a throttle failure in which the throttle valve 10 is fixed at a predetermined opening. In addition, the operating condition is such that overrun can be prevented.

Next, as described above, step S2 in FIG.
If it is determined in step 03 that the throttle valve 10 is not a throttle failure (the throttle valve 10 can be driven by the motor 11) and that another abnormality has occurred in the throttle valve control device, the process proceeds to the processing shown in FIGS. And
Thereafter, the process proceeds to the known engine control main routine. A series of processing in this case will be described.

First, based on the detection signals VPa1 and VPa2 from the first and second accelerator sensors 53 and 54, the ECU 20 firstly controls the first and second accelerator sensors 53 and 54, respectively.
It is determined whether the failure has occurred (steps S701 to S708).

For example, it is determined whether the detection signal VPa1 of the first accelerator sensor 53 is lower than a low level threshold value A (for example, 0.5 V) (step S701), and if it is lower (step S701, Yes), First accelerator sensor 5
Since a disconnection or a short circuit has occurred in No. 3, the short flag XPA1UP is turned off, and the disconnection or short flag XPA1DN is turned on (step S702).

If it is not low (step S701,
No), it is determined whether the detection signal VPa1 of the first accelerator sensor 53 is higher than a high level threshold value B (for example, 4.8 V) (step S703).
703, Yes), since a short circuit has occurred in the first accelerator sensor 53, the short flag XPA1UP is turned on, and the disconnection or short flag XPA1DN is turned off (step S704).

Further, it is determined whether or not the detection signal VPa2 of the second accelerator sensor 54 is lower than the low level threshold value A (step S705).
Yes), since the disconnection or short-circuit has occurred in the second accelerator sensor 54, the short flag XPA2UP is turned off and the disconnection or short flag XPA2DN is turned on (step S706).

If it is not low (step S705,
No), it is determined whether the detection signal VPa2 of the second accelerator sensor 54 is higher than the high level threshold value B (step S707). If it is higher (step S707 Yes), a short circuit occurs in the second accelerator sensor 54. So
The short flag XPA2UP is turned on, and the disconnection or short flag XPA2DN is turned off (step S70).
8).

Next, the ECU 20 checks each flag XPA1UP,
It is determined whether any of XPA1DN, XPA2UP, and XPA2DN is on (step S709). If any of them is on (step S709, Yes), step S71 is performed.
Move to 4. If none of them is on (step S
709, No), the first and second accelerator sensors 53, 54
Absolute value ΔVPa (= | V) of the difference between the detection signals VPa1 and VPa2
Pa1−VPa2 |) is determined (step S710), and it is determined whether the absolute value ΔVPa of the difference is lower than a predetermined error threshold E (step S711). If the absolute value ΔVPa of the difference is equal to or smaller than the error threshold value E (step S71)
1, Yes), the ECU 20 regards that the first and second accelerator sensors 53, 54 have not failed,
The abnormality flag XVPAR is set to off (step S71)
2). If the absolute value of the difference ΔVPa is higher than the error threshold value E (step S711, No), the ECU 20
It is assumed that a failure has occurred in the first and second accelerator sensors 53 and 54, and the abnormality flag XVPAR is set to ON (step S713).

Thus, the first and second accelerator sensors 5
3, 54 failures are determined, and each flag XPA1UP, XPA1DN,
After setting XPA2UP, XPA2DN, and XVPAR, the ECU 20
Determines whether at least one of the disconnection or short flag XPA1DN of the first accelerator sensor 53 and the disconnection or short flag XPA2DN of the second accelerator sensor 54 is on (step S714). If both are off (step S714, No), the ECU 20 determines whether at least one of the short flag XPA1UP of the first accelerator sensor 53 and the short flag XPA2UP of the second accelerator sensor 54 is on (step S714). S71
5). If both are off (step S715, N
o), the ECU 20 determines whether or not the abnormality flag XVPAR is on (step S716). Error flag X
If the VPAR is off (step S716, No), all the flags are off and the first and second accelerator sensors 53 and 54 are operating normally. In this case, the process proceeds to the process 1 of the step S717 (shown in FIG. 12).

In the flowchart of FIG.
20 is a detection signal VPa of the first accelerator sensor 53, for example.
The temporary accelerator opening PA corresponding to 1 is obtained (step S80).
1) Further, the provisional accelerator opening PA is calculated by the accelerator opening PACAL.
(Step S802). After this, FIG.
It moves to the processing of the flowchart of FIG.

In step S801, instead of obtaining the temporary accelerator opening PA corresponding to the detection signal VPa1 of the first accelerator sensor 53, the second accelerator sensor 54
The temporary accelerator opening PA corresponding to the detection signal VPa2 may be obtained. Also, the first and second accelerator sensors 53, 54
The temporary accelerator opening PA corresponding to the lower one of the detection signals VPa1 and VPa2 may be obtained. Alternatively, the provisional accelerator pedal opening PA corresponding to the average value of the respective detection signals VPa1 and VPa2 may be obtained.

Next, in the flowchart of FIG.
At least one of the first and second accelerator sensors 53 and 54 is disconnected or short-circuited, and the first accelerator sensor 5
If at least one of the disconnection or short flag XPA1DN of No. 3 and the disconnection or short flag XPA2DN of the second accelerator sensor 54 is on (step S714, Ye)
s) Then, the process proceeds to the process 2 of the step S718 (shown in FIG. 13).

Referring to the flowchart of FIG.
20 determines whether the first and second accelerator sensors 53 and 54 are both disconnected or short-circuited (step S901). When the first and second accelerator sensors 53 and 54 are both disconnected or short-circuited and each of the disconnection or short-circuit flags XPA1DN and XPA2DN is ON (Yes in step S901), it is not possible to specify the accelerator opening PACAL. It is possible. In this case, the ECU 20 checks whether the brake switch 17 is on or off (step 90).
2) If the brake switch 17 is on (step S902, Yes), the target throttle opening THA of the throttle valve 10 is set to 3 ° because the driver is stopping the vehicle (step S903). If the brake switch 17 is off (step S
902, No), if the driver is not trying to stop the vehicle, the target throttle opening THA of the throttle valve 10 is set to 5 ° (step S904). Thereafter, the routine proceeds to the engine control main routine, in which the opening of the throttle valve 10 is set to the target throttle opening THA (3 ° or 5 °). When the driver intends to stop the vehicle, the engine 1 rotates. The number is reduced promptly, and if the driver does not try to stop the vehicle, a rapid decrease in the rotational speed of the engine 1 is avoided.

The first and second accelerator sensors 53, 53
Only one of 54 is disconnected or short-circuited,
If only one of each disconnection or short flag XPA1DN or XPA2DN is on (step S901, No),
The ECU 20 includes first and second accelerator sensors 53 and 54.
Of the detection signals VPa1 and VPa2 at a predetermined constant K1
The tentative accelerator opening P corresponding to this quotient
A is obtained (step S905), and the process proceeds to processing 3 in FIG.

The first and second accelerator sensors 53, 5
4 is short-circuited or short-circuited, one of the detection signals VPa1 and VPa2 is lower than the low-level threshold value A (for example, 0.5 V), and the other is the operation amount of the accelerator pedal 13. Indicates the corresponding level. Therefore, the constant K1 is appropriately set in advance, and the detection signals VPa1, VPa
Dividing the sum of 2 by the constant K1 gives this quotient
The level becomes slightly lower than the level of the normal detection signal corresponding to the operation amount of No. 3, and the temporary accelerator opening PA is set slightly closer to the closing side than the opening corresponding to the operation amount of the accelerator pedal 13.

In the flowchart of FIG. 14, the ECU 20 sets the first and second accelerator sensors 53, 53
Immediately before an abnormality occurs in at least one of the flags 54, that is, immediately before at least one of the flags is turned on, the accelerator opening PACAL determined in step S802 is set as the previous accelerator opening PAOLD, and the temporary accelerator opening PAOLD determined in each step S905 is determined. Accelerator opening PA to previous accelerator opening PA
The difference (accelerator opening change) obtained by subtracting OLD is obtained, and a quotient (a value obtained by correcting the accelerator opening change) obtained by dividing the difference by a predetermined constant K3 is added to the previous accelerator opening PAOLD. Then, an accelerator opening PACAL for obtaining a target throttle opening of the throttle valve 14 is obtained (step S
1001).

Then, the ECU 20 compares the previous accelerator pedal opening PAOLD with the temporary accelerator pedal opening PA obtained in step S905 (step S1002), and determines that the temporary accelerator pedal opening PA is smaller than the previous accelerator pedal opening PAOLD. If the degree tends to decrease (step S1
002, Yes), the accelerator opening PACAL obtained in step S1001 is reset to a temporary accelerator opening PA smaller than the accelerator opening PACAL (step S100).
3). Thereafter, the accelerator opening PACAL is updated to the reset accelerator opening PACAL last time (step S100).
4).

If the provisional accelerator opening PA is equal to or greater than the previous accelerator opening PAOLD and the accelerator opening tends to increase (step S1002, No), the accelerator opening PACAL obtained in step S1001 is recalculated. Without setting, the previous accelerator opening PAOLD is set to the accelerator opening PAC
Update to AL (step S1004).

As described above, the first and second accelerator sensors 5
If at least one of the first and second accelerators 3 and 54 is disconnected or short-circuited, the temporary accelerator opening PA is set based on the detection signals VPa1 and VPa2 of the first and second accelerator sensors 53 and 54, and the temporary accelerator opening PA and The amount of change in the accelerator opening is obtained from the previous accelerator opening PAOLD, and the value obtained by correcting the amount of change is added to the previous accelerator opening PAOLD to obtain the accelerator opening PACAL. In other words, the accelerator opening PACAL is obtained by increasing or decreasing the previous accelerator opening PAOLD based on the previous accelerator opening PAOLD in a normal state. Therefore, the operation amount of the accelerator pedal 13 can be set in a normal state without abruptly changing the operation amount and sufficiently reflecting the driver's will, and the throttle opening of the throttle valve 14 can be similarly controlled. Can be.

If the accelerator opening tends to decrease, the accelerator opening PACAL is reset to the temporary accelerator opening PA. As a result, the accelerator opening PACAL decreases quickly, and the throttle valve 14
Is closed, so that safety can be improved.

Next, in the flowchart of FIG.
If at least one of the first and second accelerator sensors 53 and 54 is short-circuited and at least one of the short flag XPA1UP of the first accelerator sensor 53 and the short flag XPA2UP of the second accelerator sensor 54 is on (step S715) Yes), the process proceeds to the process 4 of the step S720 (shown in FIG. 15).

Referring to the flowchart of FIG.
20 determines whether the first and second accelerator sensors 53 and 54 are both short-circuited (step S110).
1). When both the first and second accelerator sensors 53 and 54 are short-circuited and both the short flags XPA1UP and XPA2UP are on (step S1101,
Yes), it is impossible to specify the accelerator opening PACAL.
In this case, the ECU 20 determines whether or not the shift position detected by the shift position sensor 22 is in a position suitable for high-speed traveling (for example, a traveling (D) range or a state where overdrive (OD) traveling is possible). (Step S1
102). If the shift position is not at a position suitable for high-speed traveling (step S1102, No), the ECU 20 sets the target throttle opening THA of the throttle valve 10 to 3 ° (step S1103). If the shift position is at a position suitable for high-speed traveling (step S1102,
Yes), the target throttle opening THA of the throttle valve 10 is set to 5 ° (step S1104). Thereafter, the routine proceeds to the engine control main routine, in which the opening of the throttle valve 10 is set to the target throttle opening THA (3 ° or 5 °). If the shift position is not at a position suitable for high-speed running, the engine 1 The engine speed is reduced promptly, and if the shift position is at a position suitable for high-speed running, a sudden decrease in engine speed is avoided.

Further, the first and second accelerator sensors 53,
54 is short-circuited and if only one of the short flags XPA1UP and XPA2UP is on (step S1101, No), the ECU 20 determines
Detection signal VPa of first and second accelerator sensors 53 and 54
1, a smaller one of VPa2 is selected, and a provisional accelerator pedal opening PA corresponding to the selected detection signal is obtained (step S5).
1105), and proceed to processing 3 in FIG.

In step S1105, the first
And the detection signals VPa1,
In addition to obtaining the smaller one of VPa2, the correction is made by dividing the smaller detection signal by a predetermined constant K2, and the provisional accelerator pedal opening PA corresponding to this correction value is corrected.
You may ask.

In the flowchart of FIG. 14, immediately before at least one of the flags is turned on, the ECU 20 sets the accelerator opening PACAL obtained in step S802 as the previous accelerator opening PAOLD, and obtains the accelerator opening PAOLD in each step S1105. Temporary accelerator opening PA
The difference (accelerator opening change) obtained by subtracting the previous accelerator opening PAOLD from the above is obtained, and the difference obtained by dividing the difference by a constant K3 (the value obtained by correcting the accelerator opening change) is used as the previous accelerator opening P
Accelerator opening PACAL is obtained by adding to AOLD (step S1001). As a result, the operation amount of the accelerator pedal 13 can be set in a normal state without abruptly changing, and sufficiently reflecting the driver's will.

Then, the ECU 20 proceeds to step S110.
If the temporary accelerator opening PA determined in 5 is smaller than the previous accelerator opening PAOLD and the accelerator opening tends to be smaller (Yes in step S1002), the accelerator opening PACAL determined in step S1001 is temporarily determined. The accelerator opening PA is reset (step S100
3) With this, the accelerator opening PACAL is quickly reduced. Thereafter, the accelerator opening PAOLD is updated to the reset accelerator opening PACAL (step S1004).

If the temporary accelerator opening PA is greater than or equal to the previous accelerator opening PAOLD and the accelerator opening tends to increase (step S1002, No), the accelerator opening PACAL obtained in step S1001 is recalculated. Without setting, the previous accelerator opening PAOLD is set to the accelerator opening PAC
Update to AL (step S1004).

Next, in the flowchart of FIG.
Detection signal VPa of first and second accelerator sensors 53 and 54
If the absolute value ΔVPa of the difference between 1 and VPa2 is large and the abnormality flag XVPAR is on (step S716, Ye
s), similarly to the case where at least one of the short flags XPA1UP and XPA2UP is on (step S715, Yes), the process 4 of step S721 (shown in FIG. 15) and the process 3 of step S719 (see FIG. 14). Move on).

The process 4 in step S721 is exactly the same as the process 4 in step S720 described above, and the process 3 in step S719 has been described above, so that the description of these processes will be omitted.

Thus, each of the above steps S802, 100
Accelerator opening PACAL in any of 1,1003
Is set, the process proceeds to the flow chart shown in FIG.

First, the ECU 20 sets the temporary suppression accelerator opening t_pdla equal to the accelerator opening PACAL (step S1201), and calculates the difference ed between the temporary suppression accelerator opening t_pdla and the suppression accelerator opening epdlao obtained by the previous calculation.
lpdla is obtained (step S1202), and it is determined whether or not the difference edlpdla is larger than the value F of the characteristic curve shown in the graph of FIG. 17 (step S1203). This difference edlpdla
Is less than or equal to the value F (No in step S1203), E
The CU 20 maintains the temporary suppression accelerator opening t_pdla as it is (step S1204). Also, this difference edlpdla
Is larger than the value F (step S1203, Ye
s), the ECU 20 restricts the difference edlpdla to the value F (step S1205), and then performs the previous suppression accelerator opening e
The sum of pdlao and the value F is tentatively suppressed accelerator opening t_pdl
It is reset as a (step S1204).

Next, the ECU 20 determines whether or not the temporary suppression accelerator opening t_pdla is greater than a preset value G (step S1206). Temporary suppression accelerator opening t
If _pdla is equal to or less than the value G (step S1206, N
o), the ECU 20 determines that the temporary suppression accelerator opening t_pdla
Is maintained as it is, and this temporary suppression accelerator opening t_pdla
Is set as the current throttle opening eplao and the previous throttle opening eplao (step S120).
7). If the temporary suppression accelerator opening t_pdla is larger than the value G (step S1206, Yes), the ECU 2
0 restricts the temporary suppression accelerator opening t_pdla to a value G (step S1208), and sets the temporary suppression accelerator opening t_pdla as the current suppression accelerator opening epdla and the previous suppression accelerator opening epdlao. (Step S1207).

In short, the restriction of the degree of change of the accelerator opening PACAL and the restriction of the maximum value of the accelerator opening PACAL are the suppression accelerator opening epla. The graph of FIG. 17 shows a characteristic curve of the value F with respect to the accelerator opening PACAL. With this characteristic curve, the accelerator opening PAC
As the AL increases, the degree of change of the accelerator opening PACAL is further restricted.

Next, the ECU 20 calculates the throttle opening e.
If pdla is less than the constant Ka1 (step S1209, Y
es), the target throttle opening T of the throttle valve 10
HA = 3 ° (step S1210), and if the throttle opening epdla is equal to or greater than the constant Ka1 and less than the constant Ka2 (step S1211, Yes), the target throttle opening THA is set to TH = 4 ° (step S1212), and the throttle is suppressed. If the opening epdla is equal to or greater than the constant Ka2 and less than the constant Ka3 (step S1213, Yes), the target throttle opening THA is set to 5 ° (step S1214). If the throttle opening epdla is more than the constant Ka3 and less than the constant Ka4. (Step S1215, Yes), the target throttle opening THA is set to 6 ° (Step S1216), and if the restrained accelerator opening epdla is equal to or larger than the constant Ka4 (Step S12).
16, No), the target throttle opening THA is set to 7 ° (step S1217).

As a result, the target throttle opening THA becomes
As shown in the graph of FIG. 18, the setting is made stepwise with respect to the suppression accelerator opening epla.

After setting the target throttle opening THA in this way, the routine proceeds to an engine control main routine, in which the opening of the throttle valve 10 is set to the target throttle opening THA. As a result, the opening of the throttle valve 10 becomes 3
°, 4 °, 5 °, 6 °, or 7 °.

As described above, in the present embodiment, during a throttle failure in which the throttle valve 10 is fixed at a predetermined opening, the engine output is sequentially increased in accordance with the engine output levels "1" to "5". In addition, since these controlled operating conditions are appropriately selected in accordance with the engine temperature, at the time of a throttle failure in which the throttle valve 10 is fixed at a predetermined opening, prevention of stall of the engine 1 and prevention of stall of the engine 1, respectively. Overrun can be prevented.

Further, even when the throttle control device is abnormal, if the throttle valve 10 can be driven, whether the brake pedal is operated or the shift position of the transmission is suitable for high-speed running. The driver's intention to operate is identified based on whether the vehicle is in the position, the target throttle opening of the throttle valve 10 is set in accordance with the driver's intention to operate, and the target opening of the throttle valve 10 is set in the engine control main routine. The output of the engine 1 is controlled by setting the throttle opening.

Further, even when the throttle control device is abnormal, the throttle valve 10 can be driven, and if at least one of the first and second accelerator sensors 53 and 54 is normal, the accelerator The target opening of the throttle valve 10 corresponding to the accelerator opening is set, and the opening of the throttle valve 10 is set to the target throttle opening in the engine control main routine. Is controlling.
At this time, the target throttle opening of the throttle valve 10 is changed stepwise with respect to the accelerator opening detected by the accelerator sensor. Therefore, even if noise is included in the detection output of the accelerator sensor, the target throttle opening of the throttle valve 10 is not changed. The opening does not change minutely, and the output of the engine 1 does not fluctuate accidentally due to noise. Further, since the target throttle opening of the throttle valve 10 is changed in a stepwise manner, the output of the engine 1 also changes in a stepwise manner, whereby the driver can be notified of the occurrence of a failure.

Note that the present invention is not limited to the above embodiment, but can be variously modified. For example, the method of adjusting the engine output is not limited to the above-described reduction in the number of operating cylinders and the retardation of the ignition timing, and is arbitrary.
Alternatively, for example, the engine output may be reduced by adjusting the fuel injection amount.

As for the adjustment for reducing the engine output, the reduction of the number of operating cylinders, the retardation of the ignition timing, and the adjustment of the fuel injection amount may be appropriately combined. As a result, the engine output can be adjusted more finely.

The auxiliary mechanism 40 illustrated in FIG. 2 is employed as a mechanism for fixing the throttle valve 10 at a predetermined opening at the time of a throttle failure. However, if the mechanism has the same function, the auxiliary mechanism 40 is limited. Any mechanism that is not possible can be employed.

In addition to the in-line four-cylinder four-stroke engine, the present invention can be applied to any type of vehicle-mounted engine having an actuator-driven throttle valve.

[0115]

As described above, according to the present invention, when the throttle control device is abnormal, the signal from the accelerator operation amount detecting means is converted into a different constant value for each of a plurality of predetermined operation areas. Then, a step-like signal corresponding to the accelerator operation amount is obtained, and the opening degree of the throttle valve is controlled based on the step-like signal. Therefore, even if noise is superimposed on the signal from the accelerator operation amount detecting means, this signal is kept at a certain value. As a result, the opening degree of the throttle valve does not change in response to the noise, so that the throttle valve is not easily affected by the noise.

[Brief description of the drawings]

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

FIG. 2 is a diagram schematically showing a throttle structure in the device of FIG.

FIG. 3 is a flowchart showing a procedure for determining an engine output level initial value in the apparatus shown in FIG. 1;

FIG. 4 is a diagram showing a map used for determining an engine output level initial value in the apparatus of FIG. 1;

FIG. 5 is a flowchart showing an engine output level learning procedure in the apparatus of FIG. 1;

FIG. 6 is a diagram showing a map used for engine output level learning in the apparatus of FIG. 1;

FIG. 7 is a flowchart showing an engine output level learning procedure in the apparatus of FIG. 1;

FIG. 8 is a flowchart showing a procedure for determining an engine output level in the apparatus of FIG. 1;

FIG. 9 is a view showing a map used for determining an engine output level in the apparatus of FIG. 1;

FIG. 10 is a graph showing the relationship between ignition timing and engine output in the apparatus of FIG.

11 is a flowchart showing a process for determining an abnormality of an accelerator sensor in the device of FIG. 1 and obtaining an accelerator opening degree.

FIG. 12 is a view showing a step 7 in the flowchart of FIG. 11;
17 is a flowchart illustrating a process 1 of Step 17;

FIG. 13 is step 7 in the flowchart of FIG. 11;
18 is a flowchart showing a process 2 of Step 18.

FIG. 14 is step 7 in the flowchart of FIG. 11;
21 is a flowchart showing Process 3 of Step 19;

FIG. 15 is a step 7 in the flowchart of FIG. 11;
21 is a flowchart showing Process 4 of Step 20.

FIG. 16 is a flowchart showing a process subsequent to FIG. 11 for obtaining a throttle opening.

FIG. 17 is a graph showing characteristics of a suppressed accelerator opening with respect to an accelerator opening in the apparatus of FIG. 1;

FIG. 18 is a graph showing characteristics of a target throttle opening degree with respect to a suppression accelerator opening degree in the apparatus of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 internal combustion engine (engine) 2 intake passage 3 exhaust passage 10 throttle valve 11 motor 12 throttle opening sensor 20 electronic control unit (ECU) 24 crank angle sensor 26 water temperature sensor 31 catalyst 40 auxiliary mechanism 51 accelerator pedal 53 first accelerator sensor 54 Second accelerator sensor

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshimoto Kawai 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3G065 AA04 CA39 DA05 FA12 FA13 GA01 GA09 GA10 GA11 GA29 GA31 GA41 GA46 3G301 HA01 HA06 JA09 JB01 JB07 LA01 LB02 LC03 MA13 NA08 ND02 ND21 PA07Z PA11Z PE01Z PE08Z PF01Z PF03Z PF05Z PF08Z PF10Z

Claims (4)

[Claims] 1. A throttle control of an internal combustion engine mounted on a vehicle, wherein the throttle valve of the internal combustion engine is opened and closed by an actuator, and an opening of the throttle valve is adjusted according to an accelerator operation amount detected by an accelerator operation amount detecting means. In the device, when it is detected that an abnormality has occurred in the throttle control device, an abnormal state in which the throttle valve can be opened and closed and a signal is output from the accelerator operation amount detecting means is determined. Signal processing for converting a signal from the accelerator operation amount detecting means into a constant value different from each other for each of a plurality of predetermined operation areas, and forming a step-like signal according to the accelerator operation amount Means, when the abnormality state is determined by the abnormality determination means, based on a signal from the signal processing means. And a control means for controlling the opening of the throttle valve. 2. The system according to claim 1, wherein the predetermined value of the signal processing unit is smaller than a value detected by the accelerator operation amount detecting unit when the abnormal state is not determined by the abnormality determining unit. 3. The throttle control device for an internal combustion engine according to claim 1. 3. The internal combustion engine according to claim 1, wherein the signal from the accelerator operation amount detection means used in the signal processing means is used by limiting a change speed of the signal within a predetermined value. Throttle control device. 4. The signal according to claim 1, wherein the signal from the accelerator operation amount detecting means used in the signal processing means is used by limiting the magnitude of the signal within a predetermined value. 3. The throttle control device for an internal combustion engine according to claim 1.