JPH1136894A - Throttle valve controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce vehicular shock generated on switching one sensor output to the other sensor output in a double system. SOLUTION: A throttle valve controller 1 for an internal combustion engine 10 controls a throttle valve 12 based on output from a double sensor containing a first sensor 36a and a second sensor 36b. When the first sensor 36a and the second sensor 36b are in normal, a difference between the output from the first sensor 36a and that from the second sensor 36b is memorized. Under normal control, the throttle valve control device 1 controls the throttle valve 12 based on the output from the first sensor 36a. When the first sensor 36a is in unusual, the throttle valve 12 is controlled based on the corrected output from the second sensor 36b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a throttle valve control device for an internal combustion engine.

[0002]

2. Description of the Related Art In a throttle valve control device for an internal combustion engine that electronically controls a throttle valve, it is known that an abnormality is detected by making an accelerator sensor or a throttle sensor a double system and comparing the output of each sensor. . Such a throttle valve control device is disclosed in, for example,
8853.

[0003]

As described above, in the case where the accelerator sensor and the throttle sensor are of a double system, when one of the sensors for normal control fails due to disconnection or the like, the output of the other sensor is used. Although fail-safe can be achieved by electronically controlling the throttle valve,
There is a problem that the throttle opening greatly changes when these sensor outputs are switched, and a vehicle shock occurs.

The present invention has been made to solve this problem, and has an internal combustion engine capable of reducing a vehicle shock generated at the time of switching from one sensor output of a dual sensor to the other sensor output. An object of the present invention is to provide a throttle valve control device for an engine.

[0005]

A throttle valve control apparatus for an internal combustion engine according to the present invention controls a throttle valve based on an output of a dual sensor including a first sensor and a second sensor. A control device, wherein the storage means stores a difference between an output of the first sensor and an output of the second sensor when the first sensor and the second sensor are normal, and an output of the second sensor. Means for correcting the difference based on the difference stored in the storage means;
Control means for controlling the throttle valve based on the output of the sensor, and controlling the throttle valve based on the output of the second sensor corrected by the correction means when the first sensor is abnormal. With this, the above object is achieved.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration of a throttle valve control device 1 according to an embodiment of the present invention. The throttle control device 1
Throttle valve 1 provided in internal combustion engine (engine) 10
2 is controlled. As the opening of the throttle valve 12 increases, the amount of air supplied from the air cleaner 14 to the engine 10 increases. As the opening of the throttle valve 12 decreases, the amount of air supplied from the air cleaner 14 to the engine 10 decreases.

An electronic control unit (ECU) 20 includes an input interface circuit 21, a CPU 22, and a motor drive unit 2.
3, a ROM 24, and a RAM 25.

[0009] The engine speed sensor 31
The number of rotations of 0 is detected. The output of the engine speed sensor 31 is supplied to the CPU 22 via the input interface circuit 21.
Supplied to

A vehicle speed sensor 32 detects a vehicle speed. The output of the vehicle speed sensor 32 is supplied to the CPU 22 via the input interface circuit 21.

The neutral start switch 33 detects that the shift position is N or P. The output of the neutral start switch 33 is supplied to the CPU 22 via the input interface circuit 21.

A water temperature sensor 34 detects an engine cooling water temperature. The output of the water temperature sensor 34 is supplied to the CPU 22 via the input interface circuit 21.

The accelerator sensors 35a and 35b are double sensors for detecting the accelerator opening. The accelerator opening changes according to the amount of depression of the accelerator 30. The outputs of the accelerator sensors 35a and 35b are supplied to the CPU 22 via the input interface circuit 21.

The CPU 22 comprises accelerator sensors 35a, 3
The target opening of the throttle valve 12 is determined based on the output of 5b. The actual opening of the throttle valve 12 is detected by throttle sensors 36a and 36b. The throttle sensors 36a and 36b are dual sensors for detecting the opening of the throttle valve 12. The CPU 22 controls the motor drive unit 23 so that the actual opening of the throttle valve 12 matches the target opening. The rotation of the DC motor 40 is controlled by the motor drive unit 23. The rotation of the DC motor 40 opens and closes the throttle valve 12. Through such feedback control, the opening of the throttle valve 12 is maintained at the target opening.

FIG. 2 shows a procedure of a target voltage calculation routine for calculating a target voltage VTP for controlling the DC motor 40. The target voltage calculation routine is executed by the CPU 22.

In step S10, the accelerator sensor 35
Outputs a and 35b are input to the CPU 22 via the input interface circuit 21.

In step S11, the CPU 22 calculates a target opening of the throttle valve 12 based on the outputs of the accelerator sensors 35a and 35b.

In step S12, the CPU 22 converts the calculated target opening into a target voltage VTP.

FIG. 3 shows a procedure of a throttle valve control routine. The throttle valve control routine is executed by the CPU 22. The throttle valve control routine is stored in the ROM 24 in the form of a program, for example.

In step S21, the throttle sensor 3
6a (No. 1 sensor) output and the throttle sensor 36
The output of b (No 2 sensor) is read by the CPU 22. VTA1 indicates the output voltage of the throttle sensor 36a. VTA2 indicates the output voltage of the throttle sensor 36b.

In step S22, VTA1 is substituted for VTA. VTA represents a sensor output voltage for control. This means that during normal control, the throttle sensor 3
This means that the throttle valve 12 is controlled based on the output (VTA1) of 6a.

In step S23, a sensor failure detection routine is executed.

FIG. 4 shows the procedure of a sensor failure detection routine. The sensor failure detection routine is executed by the CPU 22
Is executed at regular intervals. The certain time is, for example, 8 ms. The sensor failure detection routine is stored in the ROM 24 in the form of a program, for example.

In step S203, the absolute value (| VTA1-VTA) of the difference between the output (VTA1) of the throttle sensor 36a and the output (VTA2) of the throttle sensor 36b.
2 |) is equal to or less than a predetermined value (KDθ).

If the determination in step S203 is "No", the flag XFVTAR is set to "1" (abnormal) (step S204). If the determination in step S203 is “Yes”, the flag XFVTAR is set to “0” (normal) (step S205).

In step S206, the output (VTA1) of the throttle sensor 36a is reduced to a predetermined minimum value VTA1 _min.
Or more, and, or less than a predetermined maximum value VTA1 _max is determined.

If the determination in step S206 is "No", the flag XFVTA1 is set to "1" (abnormal) (step S207). If the determination in step S206 is “Yes”, the flag XFVTA1 is set to “0” (normal) (step S208).

[0028] In step S209, the output of the throttle sensor 36b (VTA2) minimum predetermined value VTA2 _min
Or more, and, or less than a predetermined maximum value VTA2 _max is determined.

If the determination in step S209 is "No", the flag XFVTA2 is set to "1" (abnormal) (step S210). If the determination in step S209 is “Yes”, the flag XFVTA2 is set to “0” (normal) (step S211).

As described above, the flag XFVTAR and the flag XFVTAR are set in accordance with the output (VTA1) of the throttle sensor 36a and the output (VTA2) of the throttle sensor 36b.
FVTA1, flag XFVTA2 is "0" or "1"
Is set to

Referring again to FIG. 3, in step S24, it is determined whether or not XFVTAR = 0, XFVTA1 = 0, and XFVTA2 = 0 hold.
If the determination in step S24 is "Yes", it means that both the throttle sensor 36a and the throttle sensor 36b are normal. If the determination in step S24 is “No”, it means that at least one of the throttle sensor 36a and the throttle sensor 36b is abnormal.

If the determination in step S24 is "Yes", the output of the throttle sensor 36a (VTA1)
And the output (VTA2) of the throttle sensor 36b are stored in the array DVTA [i] (step S25). Here, i represents an integer. The array DVTA [i] is, for example,
It can be stored in the RAM 25. The number of the array DVTA [i] is
This corresponds to the number of regions defined depending on the opening of the throttle valve 12. For example, the opening degree θ ₀ of the throttle valve 12,
Five regions are defined with θ ₁ , θ ₂ , θ ₃ and θ ₄ as representative opening degrees. In this case, the array DVTA [i] (i = 0 to
The value of 4) is determined according to (Equation 1).

[0033]

[Number 1] DVTA [0] = VTA1 (θ 0) - VTA2 (θ 0) DVTA [1] = VTA1 (θ 1) - VTA2 (θ 1) DVTA [2] = VTA1 (θ 2) - VTA2 (θ ₂ ) DVTA [3] = VTA1 (θ ₃ ) −VTA2 (θ ₃ ) DVTA [4] = VTA1 (θ ₄ ) −VTA2 (θ ₄ ) where VTA1 (θ) is the opening of the throttle valve 12. represents the output of the throttle sensor 36a when θ,
VTA2 (θ) represents the output of the throttle sensor 36b when the opening of the throttle valve 12 is θ.

If the determination in step S24 is "No", the process branches to case 1, case 2, case 3, and case 4.

In case 1, the output of the throttle sensor 36a (VTA1) and the output of the throttle sensor 36b (VT
This is a case where there is an abnormality between the two sensors due to the absolute value (| VTA1−VTA2 |) of the difference from A2) being larger than a predetermined value (KDθ). If the determination in step S28 is "Ye
s "and the determination in step S33 is" Yes "
If so, the process branches to Case 1. In case 1, when VTA2 is larger than VTA1, VTA2
Is assigned to VTA (steps S34 and S35). In this way, the larger one of VTA1 and VTA2 is selected as the sensor output voltage VTA for control. This process is called “Max select”. Next, the process
Proceed to step S26.

Case 2 is a case where the throttle sensor 36a is normal and the throttle sensor 36b is abnormal. If the determination in step S28 is “Yes” and the determination in step S33 is “No”, the process branches to case 2. In case 2, the process proceeds to step S26 without performing any additional process.

Case 3 is a case where the throttle sensor 36a is abnormal and the throttle sensor 36b is normal. The determination in step S28 is "No",
If the determination in step S29 is “Yes”, the process branches to case 3. In case 3, VTA
The sum of 2 and DVTA [i] is assigned to VTA (step S30). Thus, VTA2 corrected based on DVTA [i] is substituted for VTA. Next, the process proceeds to step S26.

Case 4 is a case where the throttle sensor 36a is abnormal and the throttle sensor 36b is abnormal. The determination in step S28 is "No",
And when the judgment of step S29 is "No",
The process branches to Case 4. In case 4, a fail process is executed. In the fail process, for example, the electromagnetic clutch (not shown) is turned off, and the DC motor 40 is turned off.
F (step S31). Further, a warning is issued (step S32).

In step S26, D is calculated based on VTA.
A process of feeding back the position of the C motor 40 is executed. That is, the control amount is determined such that the difference Δθ (= VTP−VTA) between the target voltage VTP and the sensor output VTA for control becomes small. The control amount is, for example,
It is calculated according to (Equation 2).

[0040]

[Number 2] control the amount _{= K p · Δθ + K i} · ∫Δθ + K d · (d
Δθ / dt) Here, K _p , K _i , and K _d are predetermined constants.

Alternatively, in step S26, the target opening degree TTP of the throttle valve 12 and the control sensor output V
Deviation Δθ from actual opening degree TA calculated based on TA (=
The control amount may be determined so that (TTP-TA) becomes smaller.

In step S27, the control amount determined in step S26 is converted into a duty ratio signal Duty. The duty ratio signal Duty is a variable-length pulse signal having a duty ratio corresponding to the control amount.
The duty ratio signal Duty is applied to the DC motor 40. Thus, the DC motor 40 is driven.

FIGS. 5A to 5C are diagrams for explaining a vehicle shock that occurs when the sensor output is switched in the conventional throttle valve control device.

In FIG. 5A, the solid line indicates the output characteristic of the throttle sensor 36a (No. 1 sensor), and the broken line indicates the output characteristic of the throttle sensor 36b (No. 2 sensor). When the output of the No. 1 sensor becomes 0 due to disconnection or the like at the opening A of the throttle valve 12, it is determined that the No. 1 sensor has failed, and the control sensor output VTA becomes N.
The output from the o1 sensor (VTA1) is switched to the output from the No2 sensor (VTA2). When the sensor output is switched, the sensor output VTA for control temporarily decreases (see FIG. 5C). Therefore, the throttle valve 1
The throttle valve 12 is controlled to open excessively in the vicinity of the opening A of 2 (see FIG. 5B). As a result, a vehicle shock occurs.

FIGS. 6A to 6C are diagrams for explaining that the vehicle shock generated when the sensor output is switched in the throttle valve control device 1 of the present invention is reduced.

In FIG. 6A, the solid line indicates the output characteristic of the throttle sensor 36a (No. 1 sensor), and the broken line indicates the output characteristic of the throttle sensor 36b (No. 2 sensor). When the output of the No. 1 sensor becomes 0 due to disconnection or the like at the opening B of the throttle valve 12, it is determined that the No. 1 sensor has failed, and the control sensor output VTA becomes N.
The output from the o1 sensor (VTA1) is switched to the corrected output (VTA2 ') from the No2 sensor. The corrected output VTA2 'is obtained by adding the value of the array DVTA [i] to the output VTA2 of the No2 sensor.
In FIG. 6A, the corrected output VTA2 ′ is represented as “virtual sensor output”.

As described above, by generating the "virtual sensor output", it is possible to suppress a decrease in the sensor output VTA for control which occurs when the sensor output is switched (see FIG. 6C). Therefore, the throttle valve 12
Is controlled so that the throttle valve 12 is excessively opened near the opening B of FIG. 6 (see FIG. 6B). As a result, vehicle shock is reduced.

In the above-described embodiment, an example has been described in which the control by the throttle valve control device of the present invention is applied to a double throttle sensor. The control by the throttle valve control device of the present invention can be applied to a dual accelerator sensor. However, accelerator sensor 3
If the abnormality is between the sensor 5a and the accelerator sensor 35b, it is necessary to select the smaller one of the output of the accelerator sensor 35a and the output of the accelerator sensor 35b as the sensor output for control. This process is called “Min Select”.

[0049]

According to the throttle valve control device for an internal combustion engine of the present invention, during normal control, the throttle valve is controlled based on the output of the first sensor, and when the first sensor is abnormal, correction is made by the correction means. The throttle valve is controlled based on the output of the second sensor. Thus, the first
By using the output of the second sensor corrected by the correction unit when the sensor is abnormal, it is possible to reduce the fluctuation of the throttle opening that occurs when switching from the output of the first sensor to the output of the second sensor. it can. This allows
Vehicle shock can be reduced.

[Brief description of the drawings]

FIG. 1 shows a throttle valve control device 1 according to an embodiment of the present invention.
FIG. 3 is a diagram showing the configuration of FIG.

FIG. 2 is a flowchart illustrating a procedure of a target voltage calculation routine.

FIG. 3 is a flowchart showing a procedure of a throttle valve control routine.

FIG. 4 is a flowchart illustrating a procedure of a sensor failure detection routine.

FIGS. 5A to 5C are diagrams for explaining a vehicle shock that occurs when a sensor output is switched in a conventional throttle valve control device.

FIGS. 6A to 6C are diagrams for explaining that a vehicle shock generated when switching a sensor output in the throttle valve control device 1 of the present invention is reduced.

[Explanation of symbols]

 Reference Signs List 1 throttle valve control device 10 internal combustion engine 12 throttle valve 14 air cleaner 20 ECU 21 input interface circuit 22 CPU 23 motor drive unit 24 ROM 25 RAM 30 accelerator 31 engine speed sensor 32 vehicle speed sensor 33 neutral start switch 34 water temperature sensors 35a, 35b accelerator Sensor 36a, 36b Throttle sensor 40 DC motor

Continuation of the front page (72) Inventor Osamu Fukazawa 1-1-1 Showa-cho, Kariya-shi, Aichi Prefecture Inside DENSO Corporation

Claims (1)

[Claims] 1. A throttle valve control device for an internal combustion engine for controlling a throttle valve based on an output of a dual sensor including a first sensor and a second sensor, wherein the first sensor and the second sensor are provided. Storage means for storing the difference between the output of the first sensor and the output of the second sensor when normal, and correction for correcting the output of the second sensor based on the difference stored in the storage means Means for controlling the throttle valve based on the output of the first sensor during normal control, and controlling the throttle valve based on the output of the second sensor corrected by the correction means when the first sensor is abnormal. A throttle valve control device for an internal combustion engine, comprising: control means for controlling a throttle valve.