JP2002235595A - Electronic throttle controller of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a higher turn out traveling performance while assuring the same safety as before. SOLUTION: When an electronic throttle system detects an error, if a throttle opening at that time is equal to or below a limp home opening, a motor is turned off (steps 201, 202, 205), and a throttle valve is opened to the limp home opening by a limp home mechanism to assure an intake air amount at the time of turn out traveling. When an actual throttle opening when the error is detected is larger than the limp home opening, if an accelerator is not closed nor a brake is not depressed, the motor is kept turned on (steps 202, 203, 204), and the throttle opening at that time is maintained to continue a high speed traveling and a climbing traveling. The excess amount of an engine torque is suppressed by cylinder cut-off operation (step 206) to assure a safety.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called electronic throttle system, and more particularly to an electronic throttle control for an internal combustion engine which enables a limp home by returning a throttle opening mechanically to a limp home opening by a limp home mechanism when a throttle is abnormal. It concerns the device.

[0002]

2. Description of the Related Art In an electronic throttle system mounted on an automobile, for example, as shown in FIG. 2, a depression amount of an accelerator pedal 26 (accelerator operation amount) is detected by an accelerator sensor 27, and a target is set in accordance with the detected value. In some cases, the throttle opening is set, and the throttle valve 15 is driven by a motor 17 so that the opening of the throttle valve 15 (actual throttle opening) matches the target throttle opening.

[0003] In this electronic throttle system, a limp home mechanism 4 is used as a means for enabling limp-home running when an abnormality occurs.
7 (also called an opener mechanism).
The limp home mechanism 47 is arranged so as to engage the limp home member 40 on the open side of the valve lever 38, and applies the pulling force of the return spring 41 for biasing the limp home member 40 in the closing direction to the valve lever 38. It is set to be larger than the pulling force of the evacuation traveling spring 39 biased in the opening direction, and the motor 17 is turned off (OF
F). Accordingly, when the throttle is abnormal (when the motor 17 is turned off), the valve lever 38 is moved by the limp home member 40 as shown in FIG.
Position (actual throttle opening) of limp home stopper 4
By keeping the limp home opening regulated by the formula (2), the amount of intake air at the time of evacuation traveling is ensured, and evacuation traveling is enabled.

[0004]

Generally, the limp home opening is set to a minimum opening required for limp-home traveling, and the amount of intake air sufficient to maintain a constant speed traveling of about 50 to 60 km / h. Can only be secured. Therefore, when an abnormality of the electronic throttle system occurs during traveling on a highway or an uphill road, when the motor 17 is turned off and the throttle opening is closed to the limp home opening by the limp home mechanism 47, high speed traveling is performed. And cannot continue climbing.

[0005] The present invention has been made in view of such circumstances, and its object is to ensure safety even when an abnormality occurs in the electronic throttle system during traveling on a highway or an uphill road. High-speed running and uphill running can be continued while the engine output is moderately suppressed during low-speed running and idling, realizing higher evacuation driving performance while maintaining the same safety as before It is an object of the present invention to provide an electronic throttle control device for an internal combustion engine that can perform the above operation.

[0006]

In order to achieve the above object, an electronic throttle control device for an internal combustion engine according to the first aspect of the present invention detects abnormalities in which a throttle valve cannot be normally driven by abnormality detecting means. When an abnormality is detected, the energization of the throttle actuator is controlled by the abnormality-time control means as follows. When the throttle opening at the time of abnormality detection is equal to or less than a predetermined opening, the energization of the throttle actuator is stopped, and the throttle opening is mechanically returned to the limp home opening by the limp home mechanism, so that suction during evacuation traveling is performed. Secure the amount of air to enable safe evacuation as before.

On the other hand, if the throttle opening at the time of abnormality detection is larger than the predetermined opening, the throttle actuator is continuously energized, and the excess throttle output is reduced while maintaining the previous throttle opening. Suppressed by output suppression control such as cylinder operation. In this way, even if an abnormality occurs in the electronic throttle system during traveling on a highway, an uphill road, or the like, if the throttle opening at that time is larger than a predetermined opening, the throttle opening is maintained in a predetermined manner. High-speed running and uphill running can be continued, and when the engine output at that time exceeds the required value, the surplus of the engine output is suppressed by the output suppression control, and the safety at high speed running and uphill running is also improved. Secured. Thereafter, when the vehicle shifts from high-speed running (or uphill running) to low-speed running or idling during evacuation running, the surplus of the engine output is suppressed by the output suppression control. Even when the speed is higher than the predetermined value, the output of the engine is suppressed to a value corresponding to the low-speed running or the idling operation, and the safety at the low-speed running or the idling operation is secured.

In this case, the "predetermined opening" used for determining whether or not the energization of the throttle actuator is stopped when an abnormality is detected may be set to an opening different from the limp home opening. In consideration of the fact that the limp home opening is set so as to secure the intake air amount during limp-home running, the "predetermined opening" may be set to the limp home opening. With this configuration, when the throttle opening at the time of abnormality detection is equal to or less than the limp home opening, the energization of the throttle actuator is stopped, and the throttle opening is mechanically opened to the limp home opening by the limp home mechanism. Therefore, the amount of intake air at the time of limp-home running can be increased and the evacuation running performance can be improved as compared with the case where the throttle opening at or below the limp home opening is maintained as expected.

Further, when the driver closes the accelerator or depresses the brake during the limp-home running, it means that the driver is trying to decelerate or stop the vehicle. Even when the vehicle is in the limp mode while energizing the throttle actuator at times,
When the accelerator is closed or the brake is depressed, it is preferable to stop energization of the throttle actuator and mechanically close the throttle opening to the limp home opening by the limp home mechanism. With this configuration, even when the vehicle is in limp mode with the throttle opening largely opened at the time of abnormality detection, the throttle opening is mechanically reduced to the limp home opening by the limp home mechanism when the accelerator is closed or the brake is depressed. Closed, thereby reducing the amount of intake air and lowering the engine output, and reducing the throttle opening to increase the negative pressure of the intake pipe acting on the brake booster to increase the effectiveness of the brake The vehicle can be decelerated or stopped quickly during the limp-home run.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. First, a schematic configuration of an entire control system of an engine 11, which is an internal combustion engine, will be described with reference to FIG. An air cleaner 13 is mounted on an upstream side of an intake pipe 12 of the engine 11, an air flow meter 14 for measuring an intake air amount Ga is installed on a downstream side thereof, and a throttle valve 15 is further provided on a downstream side thereof. . A motor 17 (throttle actuator) such as a DC motor is connected to a rotation shaft 15 a of the throttle valve 15, and the opening of the throttle valve 15 (throttle opening) is controlled by the driving force of the motor 17. The degree is detected by the throttle opening sensor 18.

An intake manifold 1 for introducing intake air passing through a throttle valve 15 into each cylinder of the engine 11
An injector 20 is attached to the cylinder 9, and a spark plug 21 is attached to a cylinder head of each cylinder of the engine 11.
Is attached. Crankshaft 22 of engine 11
A crank angle sensor 24 is provided so as to face the outer periphery of the signal rotor 23 fitted on the crank angle sensor 2.
The pulse of the engine speed signal Ne output from 4 is taken into an electronic control unit (ECU) 25, and the engine speed is detected based on the frequency of generation of the engine speed signal Ne.

On the other hand, the depression amount of the accelerator pedal 26 (accelerator operation amount) is detected by an accelerator sensor 27, and a voltage signal Ap corresponding to the accelerator operation amount is taken into the electronic control unit 25 via an A / D converter 28. It is. In addition, the electronic control unit 25 also supplies each voltage signal of the intake air amount Ga detected by the air flow meter 14 and the throttle opening TA detected by the throttle opening sensor 18 to the electronic control unit 25.
The data is taken in via the / D converter 28.

The electronic control unit 25 includes a CPU 2
9, a microcomputer including a ROM 30, a RAM 31, and the like. The CPU 29 executes various engine control programs stored in the ROM 30 to control the ignition timing of the ignition plug 21 and to control the injector drive. The pulse width of the injection signal given to the injector 20 via the circuit 45 is controlled to control the fuel injection amount. Furthermore, this electronic control unit 25
By executing various programs for throttle control stored in the M30 by the CPU 29, at the time of normal throttle control, via the motor drive circuit 32 according to the target throttle opening set based on the accelerator operation amount Ap and the like. The motor 17 is feedback controlled by PID control or PI control, and the throttle opening is controlled to the target throttle opening by the driving force of the motor 17.

On the other hand, from the motor drive circuit 32 to the motor 17
A safety circuit 46 composed of a relay or the like is provided in the energization path, and as described later, when an abnormality of the electronic throttle system is detected, if the throttle opening is equal to or less than the limp home opening, an electronic circuit is provided. By outputting a motor stop signal from the control unit 25 to the safety circuit 46, the safety circuit 46 is operated to stop energization of the motor 17.

Next, the configuration of the electronic throttle system will be described with reference to FIGS. An accelerator lever 34 is connected and fixed to a rotation shaft 33 of the accelerator pedal 26.
5 and 36 (the accelerator is closed). When the accelerator pedal 26 is not depressed (accelerator closed), the accelerator lever 34 is held in a state in which the accelerator return springs 35 and 36 are in contact with the accelerator fully closed stopper 37. During the operation of the engine, the position of the accelerator lever 34 is detected by the accelerator sensor 27 as the accelerator operation amount Ap.

On the other hand, the rotation shaft 15 of the throttle valve 15
A valve lever 38 is connected and fixed to a, and the valve lever 38 is urged upward (in the opening direction of the throttle valve 15) in FIG. The limp home member 4 is attached to the open side of the valve lever 38.
0 are arranged so as to engage with each other.
0 is urged downward in FIG. 2 (the direction in which the throttle valve 15 is closed) by the return spring 41. The tensile force of the return spring 41 is set to be larger than the tensile force of the limp home spring 39. Note that the valve lever 38, the limp home spring 39, the limp home member 40, the return spring 41, and the limp home stopper 42 constitute a limp home mechanism 47.

During normal control (when the motor 17 is ON),
The opening of the throttle valve 15 (throttle opening) is adjusted by rotating the motor 17 forward or backward according to the operation of the accelerator pedal 26, and the throttle opening at that time is detected by the throttle opening sensor 18. At this time, when opening the throttle opening, the motor 17 is rotated forward and
As shown in FIG. 2A, the valve lever 38 is pulled against the limp home member 40 against the pulling force of the return spring 41.
, The throttle valve 15 is driven in the opening direction. Conversely, when closing the throttle opening, the throttle valve 15 is driven in the closing direction while the motor 17 is rotated in the reverse direction to lower the valve lever 38, and the throttle valve 15 is moved to the fully closed position (throttle opening degree). = 0d
When the valve lever 38 is closed to the position (eg), the valve lever 38 comes into contact with the throttle fully closed stopper 43, and further rotation is prevented.

On the other hand, when an abnormality of the electronic throttle system is detected, a motor stop signal is output from the electronic control unit 25 to the safety circuit 46 when the throttle opening is equal to or less than the limp home opening. The circuit 46 is operated to stop (OFF) the energization of the motor 17. As a result, as shown in FIG. 2B, the tensile force of the return spring 41 overcomes the tensile force of the limp home spring 39, and the limp home member 40 is kept in contact with the limp home stopper 42. In this state, the position of the valve lever 38 (throttle opening) of the limp home member 40 is regulated by the limp home stopper 42 to a predetermined opening (for example, an intake air amount sufficient to maintain a constant speed traveling of about 50 to 60 km / h). Opening that can secure
(Hereinafter, this opening is referred to as “limp home opening”), and the intake air amount during the limp-home running is ensured.

The electronic control unit 25 controls the throttle opening by executing the programs shown in FIGS. 4 to 6 by the CPU 29 during the operation of the engine, and when the operation of the throttle valve 15 becomes abnormal, the electronic control unit 25 executes the program. Depending on whether or not the throttle opening is equal to or less than the limp home opening, the power supply to the motor 17 is switched between stopping and continuing the power supply, and the output suppression control for suppressing the surplus of the engine torque is performed. Hereinafter, the processing contents of these programs will be described.

[Throttle anomaly detection] The throttle anomaly detection program shown in FIG. 4 is executed at a predetermined cycle during the operation of the engine, and serves as an abnormality detection means for detecting an abnormality in which the throttle valve 15 cannot be normally driven during the operation of the engine. Fulfill. When the program is started, first, in step 101, it is determined whether or not the deviation (absolute value) between the target throttle opening and the actual throttle opening is equal to or more than a predetermined value.
If the deviation (absolute value) between the target throttle opening and the actual throttle opening is smaller than a predetermined value, this program is terminated as it is. This is because, even if the actual throttle opening does not change for a while, if the actual throttle opening is controlled near the target throttle opening, it can be estimated that the throttle valve 15 is operating normally.

On the other hand, if it is determined in step 101 that the deviation (absolute value) between the target throttle opening and the actual throttle opening is equal to or larger than a predetermined value, the process proceeds to step 102,
It is determined whether the throttle valve 15 has been stopped for a predetermined time or more. That is, if the throttle valve 15 has been stopped for a predetermined period of time or more despite a large deviation between the target throttle opening and the actual throttle opening, the throttle valve 15 may have stopped abnormally for some reason. When it is determined that the electronic throttle system has failed, the program proceeds to step 103, where it is determined that the electronic throttle system is abnormal. On the other hand, if the throttle valve 15 has not been stopped for a predetermined time or more, it is regarded as normal, and this program ends.

Incidentally, the abnormality detection method may be changed as appropriate.
For example, when the deviation (absolute value) between the target throttle opening and the actual throttle opening is equal to or more than a predetermined value continues for a predetermined time or more, it may be determined that there is an abnormality. That is, since the deviation between the target throttle opening and the actual throttle opening is caused by the response delay of the electronic throttle system, the response of the actual throttle opening to the target throttle opening is delayed if the electronic throttle system is normal. And the state where the deviation between the target throttle opening and the actual throttle opening is large does not continue for a long time. Therefore,
When the state where the deviation between the target throttle opening and the actual throttle opening is large continues for a long time (that is, when the deviation between the target throttle opening and the actual throttle opening is equal to or more than a predetermined value continues for a predetermined time or more) Since the throttle valve 15 does not operate normally for some reason, it can be determined that the throttle valve 15 is abnormal.

[Throttle Control] The throttle control program shown in FIG. 5 is executed at a predetermined cycle while the engine is operating.
The throttle opening is controlled as follows. First, in step 201, it is determined whether or not an abnormality of the electronic throttle system has been detected by the abnormality detection program of FIG.
Proceed to 7 to execute normal throttle control. In the normal throttle control, the motor 17 is feedback-controlled by PID control or PI control via the motor drive circuit 32 in accordance with a target throttle opening set based on an accelerator operation amount or the like, and the driving force of the motor 17 is controlled. Thus, the throttle opening is controlled to the target throttle opening.

On the other hand, if an abnormality of the electronic throttle system is detected in step 201, the process proceeds to step 202, where it is determined whether or not the actual throttle opening is equal to or less than the limp home opening. If it is equal to or less than the limp home opening, the process proceeds to step 205, and the energization of the motor 17 is stopped. As a result, the throttle valve 15 is opened to the limp home opening by the limp home mechanism 47, and the amount of intake air during the limp-home running is ensured.

If it is determined in step 202 that the actual throttle opening at the time of abnormality detection is larger than the limp home opening, the process proceeds to step 203, where it is determined whether the accelerator is closed or the brake is depressed. If neither the accelerator is closed nor the brake is depressed, the process proceeds to step 204, and the energization of the motor 17 is continued. In this way, even if the electronic throttle system is abnormal while traveling on a highway or an uphill road, if the throttle opening at that time is larger than the limp home opening, the throttle opening is maintained as expected. High-speed running and uphill running can be continued.

On the other hand, even when the actual throttle opening at the time of detecting the abnormality is larger than the limp home opening (that is, when energization of the motor 17 is continued), it is determined in step 203 that the accelerator is closed or the brake is depressed. If so, the routine proceeds to step 205, where the energization of the motor 17 is stopped, and the throttle valve 15 is closed by the limp home mechanism 47 to the limp home opening.

In this way, the limp home mechanism 47 mechanically reduces the throttle opening by the limp home mechanism 47 even when the vehicle is in limp-home mode with the throttle opening largely open when an abnormality is detected and when the accelerator is closed or the brake is depressed. By closing to the home opening, it is possible to reduce the engine output by reducing the amount of intake air, and by reducing the throttle opening, the intake pipe negative pressure acting on the brake booster is increased. The effectiveness of the brake can be improved, and the vehicle during the limp-home operation can be quickly decelerated or stopped.

In the case where the energization of the motor 17 is continued (step 204) or the energization of the motor 17 is stopped (step 205) when an abnormality is detected, the process proceeds to step 206 and the output suppression shown in FIG. By executing the control program, the surplus of the engine torque is suppressed by the reduced-cylinder operation, and the safety during the limp-home running is ensured. The processing of steps 201 to 206 described above plays a role as abnormal time control means described in the claims.

[Output Suppression Control] The output suppression control program shown in FIG. 6 is a subroutine executed in step 206 of the throttle control program shown in FIG. When the program is started, first, in step 301, engine operation parameters such as the current accelerator operation amount, engine rotation speed, intake air amount and the like are read, and in the next step 302, a map is generated based on the current accelerator operation amount and the like. Alternatively, the current required torque Tap is calculated by an equation.

Thereafter, the routine proceeds to step 303, where the current actual torque Tga is calculated by a map or a mathematical expression based on the current engine speed, intake air amount, etc.
The program proceeds to 04, where the excess of the required torque Tap of the actual torque Tga (excess torque ΔT) is calculated. ΔT = Tga−Tap

Then, in the next step 305, the number of stopped cylinders Nfc (the number of cylinders in which fuel injection is stopped) according to the surplus torque ΔT is calculated by using a map or the like. At this time, the number of deactivated cylinders Nfc is set to increase as the surplus torque ΔT increases. Thereafter, the process proceeds to step 306, in which the deactivated cylinder of the engine 11 is set according to the deactivated cylinder number Nfc, and fuel is injected into only the other cylinders to execute the reduced cylinder operation, thereby reducing the engine torque to the excess torque ΔT. The required torque is controlled by lowering the torque by the minute.

In the present embodiment described above, even if an abnormality of the electronic throttle system occurs during traveling on a highway, an uphill road, or the like, if the throttle opening at that time is larger than the limp home opening, the motor 17 is driven. Since energization is continued and the throttle opening at that time is maintained depending on the situation, high-speed running and uphill running can be continued even in the event of an abnormality. Moreover, if the actual torque Tga at that time becomes equal to or more than the required torque Tap, the surplus Δ
Since T is suppressed by the output suppression control (reduced cylinder operation), sufficient safety can be ensured even when high-speed running or uphill running is performed during limp-home travel.

When the vehicle shifts from high-speed running (or uphill running) to low-speed running or idling during evacuation running, the surplus ΔT of the engine torque is reduced in output control (reduced cylinder operation).
Therefore, even when the throttle opening at that time is equal to or greater than the limp home opening, the engine torque can be suppressed to a value corresponding to the low-speed running or idling operation. Safety at the time can also be ensured.

In addition, even when the vehicle is in the limp-home mode while energizing the motor 17 continuously when an abnormality is detected, the energizing of the motor 17 is stopped when the accelerator is closed or the brake is depressed. Even when the vehicle travels in the open state, when the accelerator is closed or the brake is depressed, the limp home mechanism 47 can mechanically close the throttle opening to the limp home opening, thereby reducing the amount of intake air. By reducing the engine torque and decreasing the throttle opening, the intake pipe negative pressure acting on the brake booster can be increased to improve the effectiveness of the brakes, and It can be decelerated or stopped immediately. In the present embodiment, the output suppression control at the time of abnormality detection is performed by the reduced cylinder operation.
Other controls may be used.

In addition, in the present invention, the configuration of the electronic throttle system may be appropriately changed. For example, a configuration may be adopted in which an electromagnetic clutch is interposed between the motor 17 and the rotation shaft 15a of the throttle valve 15. Or, the intake pipe 12
May be provided with a bypass air passage that bypasses the throttle valve 15, and an ISC valve provided in the bypass air passage may be used to control the amount of intake air during idling.

Further, the "predetermined opening" used for determining whether or not to stop the energization of the motor 17 when an abnormality is detected may be changed as appropriate, or the opening of the limp home mechanism 47 may be different from the limp home opening. It may be set at any time.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an entire engine control system showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an electronic throttle system.
(A) is a diagram showing a state during normal control (when the motor is ON),
(B) is a diagram showing a state when the motor is off.

FIG. 3 is a perspective view of an electronic throttle system.

FIG. 4 is a flowchart showing a processing flow of a throttle abnormality detection program;

FIG. 5 is a flowchart showing a processing flow of a throttle control program;

FIG. 6 is a flowchart showing a flow of processing of an output suppression control program.

[Explanation of symbols]

11: engine (internal combustion engine), 12: intake pipe, 14: air flow meter, 15: throttle valve, 17: motor (throttle actuator), 18: throttle opening sensor, 25: electronic control unit (abnormality detecting means, when abnormal Control means), 26 ... accelerator pedal, 27 ... accelerator sensor, 34 ... accelerator lever, 35, 36 ... accelerator return spring, 37 ... accelerator fully closed stopper,
38: valve lever, 39: limp home spring,
40: Limp home member, 41: Return spring,
Reference numeral 42 denotes a limp home stopper, 43 denotes a throttle fully closed stopper, and 47 denotes a limp home mechanism.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F02D 17/02 F02D 17/02 R 29/02 311 29/02 311C 311F 41/22 310 41/22 310E 310K 310M 330 330S F term (reference) 3G065 AA04 CA34 CA39 DA05 DA15 EA07 FA07 FA12 GA05 GA10 GA29 GA41 GA46 HA19 HA21 HA22 JA04 JA09 JA11 KA02 KA16 3G084 AA03 BA05 BA13 CA03 CA04 DA27 DA30 DA33 EA04 EA11 EB03 EB03 EB03 FA10 FA33 3G092 AA01 AA05 AA14 BB02 BB10 CA03 CB05 DC03 DE01S DG08 EA09 EA11 EA14 EB02 EB03 EB05 EB09 EC02 EC10 FB02 FB03 FB05 FB06 GA03 FA01ZHA06X HA06Z HE01Z HF08BA01 BA09 DA09 BA09 FA08 FA10 FA11 FA12 FB05 3G301 HA01 HA07 JA35 JB01 JB02 JB08 JB09 KA06 LA03 LB02 LC03 MA11 MA24 NA03 NA04 NA05 NA06 NA08 NB03 NB13 NC04 ND02 ND05 NE17 NE23 PA01Z PA11A PA11Z PE01Z PF03Z PF05Z

Claims (3)

[Claims] 1. An electronic throttle control device for an internal combustion engine, comprising: a throttle actuator for electrically driving a throttle valve; and a limp home mechanism for returning a throttle opening to a limp home opening when power supply to the throttle actuator is stopped. Abnormality detecting means for detecting an abnormality that cannot drive the throttle valve normally, and abnormal time control means for controlling energization of the throttle actuator when the abnormality detecting means detects an abnormality, wherein the abnormal time control means When the throttle opening at the time of abnormality detection is equal to or less than the predetermined opening, the energization of the throttle actuator is stopped to return the throttle opening to the limp home opening, and the throttle opening at the time of abnormality detection is larger than the predetermined opening. When the engine output is An electronic throttle control device for an internal combustion engine, which performs an output suppression control for suppressing a surplus. 2. The electronic throttle control device for an internal combustion engine according to claim 1, wherein the predetermined opening is set to the limp home opening. 3. The abnormal state control means stops energizing the throttle actuator when the accelerator is closed or the brake is depressed, even in a throttle opening range in which energizing of the throttle actuator is continued when an abnormality is detected. The electronic throttle control device for an internal combustion engine according to claim 1 or 2, wherein