JP4688924B2 - Throttle control device for internal combustion engine - Google Patents

Description

  The present invention relates to a throttle control device for an internal combustion engine, and more particularly, detects an opening amount of a throttle valve disposed in an intake pipe of an automobile engine by a throttle opening sensor, and performs feedback control to a desired opening position by a throttle actuator. The present invention relates to a throttle control device for an internal combustion engine.

  As a prior art document relating to the reference value learning of the throttle opening when the throttle valve is driven and controlled by the throttle actuator, for example, there is a “throttle control device for an internal combustion engine” disclosed in Patent Document 1 below. In Patent Document 1, the motor that drives the throttle valve is controlled by PWM (pulse width modulation), and the motor current is controlled by changing the drive duty ratio in the PWM control. The throttle control device for an internal combustion engine that reduces the number of learning times and improves the durability of the mechanical system while maintaining the reliability of the reference value learning in the throttle valve opening / closing control. Is disclosed. In the patent document 1, when the ignition switch is ON and the starter is OFF, the throttle valve is closed to the fully closed stopper position by driving the motor, and the valve lever is abutted against the fully closed stopper. At this time, the throttle opening of the throttle valve detected by the throttle opening sensor is learned as a reference value. This learning of the reference value is prohibited when the difference in cooling water temperature between the previous stop and the current start of the internal combustion engine is below a predetermined value, thereby reducing the number of times of learning of the reference value in the throttle valve opening / closing control. The durability of the mechanical system can be improved while maintaining the reliability of the reference value learning.

  Further, as a prior art document relating to the reference position update of the throttle opening, there is a “throttle valve control device” disclosed in Patent Document 2 below. In Patent Document 2, a throttle valve that can be opened and closed and that can come into contact with a stopper, a drive unit that operates the throttle valve in a valve opening direction and a valve closing direction, and an opening that detects a throttle opening of the throttle valve. In a throttle valve control device comprising a degree detection means and a reference position update means for updating a reference position of the throttle opening of the throttle valve, when the reference position is updated when the ignition switch is turned off, the throttle valve is set to the stopper position. A reference position updating method is disclosed in which the impact applied to the throttle valve or the throttle valve operating mechanism is moderately applied, and the durability can be improved.

JP 2003-138971 A JP-A-9-303186

  However, in the “throttle control device for an internal combustion engine” disclosed in Patent Document 1, the ignition switch is turned on when the internal combustion engine is started, the starter is turned off (before cranking), and when the internal combustion engine is stopped. Reference value learning is performed immediately after the switch is turned off. During reference value learning, forced abutment control is performed to regulate the throttle valve at a predetermined opening position. When the mechanical system around the throttle valve drive shaft is distorted and the mechanical system around the drive shaft is made of a resin material, the mechanical strain increases due to the abutting control during the reference value learning. There were problems such as the possibility of component failure due to repeated fatigue.

  Further, in the “throttle valve control device” disclosed in Patent Document 2, it is necessary to gently apply the throttle valve to the stopper position when updating the reference position, and the time required for updating the reference position becomes longer. If you try to update the reference position, the engine startability will deteriorate, so it must be done when the engine stops after the ignition switch is turned off.In this case, self-shutdown is required to open and close the throttle valve after the ignition switch is turned off.・ Relays (relays that supply power to the electronic control unit (ECU) and throttle actuator for a predetermined time after the ignition switch is turned off and turn off after the predetermined time) are required, resulting in increased costs, and when the throttle opening reference position is updated. Slot valve at stopper position Battery current consumption is a problem, such as increased by a relatively large motor current flowing when butting.

  The present invention has been made to solve such a problem, and it is an object of the present invention to provide a throttle control device for an internal combustion engine capable of improving the durability of components, reducing costs, and reducing current consumption. Objective.

  The present invention includes a throttle valve that adjusts an intake air amount to the engine, a throttle opening sensor that detects an opening of the throttle valve and outputs an actual throttle opening value, a motor that drives the throttle valve, When the motor is not energized, the throttle actuator with an intermediate opening position holding mechanism that holds the throttle valve at the intermediate opening position, and the actual throttle opening value detected by the throttle opening sensor coincide with the target value. And a control unit that feedback-controls the throttle opening, and further includes a crank angle sensor that detects the engine rotation speed, and an accelerator opening sensor that detects the accelerator opening, The control unit is configured to detect the accelerator opening detected by the accelerator opening sensor and the previous position. Based on the engine rotational speed detected by the crank angle sensor, the throttle opening request value setting means for setting the throttle opening request value during engine operation, and the throttle opening sensor when the motor is in a non-energized state Whether the intermediate opening position holding mechanism is normal when the output actual throttle opening value is within a predetermined range with respect to a preset reference value of the intermediate opening position, and the other is abnormal. An intermediate opening position holding mechanism abnormality detecting means for detecting whether the motor is abnormal, and a throttle actuality from the throttle opening sensor when the motor is in a non-energized state and the intermediate opening position holding mechanism abnormality detecting means has not detected an abnormality. An intermediate opening position learning means for learning the opening value as an intermediate opening position learning value, and a normal operation region based on the intermediate opening position learning value. The throttle opening set by the throttle opening required value setting means is obtained by obtaining an opening operating area, a second opening operating area that is a throttle fully closed area, and a third opening operating area that is a throttle fully open area. Opening range determining means for determining whether the required value corresponds to one of the first, second, and third opening operating areas, and the throttle opening set by the throttle opening required value setting means The opening degree determined by the opening area determining means so that the required value is equal to or less than a throttle opening speed limit value set in advance for each of the first, second, and third opening operation areas. The throttle opening command value setting means for limiting the speed according to the operating region and outputting the throttle opening command value, and the throttle opening value detected by the throttle opening sensor is the throttle opening value. Throttle opening feedback control means for performing feedback control of the throttle opening so as to coincide with the throttle opening command value output from the command value setting means, and outputting a motor drive duty value to the motor. A throttle control device for an internal combustion engine.

  The present invention includes a throttle valve that adjusts an intake air amount to the engine, a throttle opening sensor that detects an opening of the throttle valve and outputs an actual throttle opening value, a motor that drives the throttle valve, When the motor is not energized, the throttle actuator with an intermediate opening position holding mechanism that holds the throttle valve at the intermediate opening position, and the actual throttle opening value detected by the throttle opening sensor coincide with the target value. And a control unit that feedback-controls the throttle opening, and further includes a crank angle sensor that detects the engine rotation speed, and an accelerator opening sensor that detects the accelerator opening, The control unit is configured to detect the accelerator opening detected by the accelerator opening sensor and the previous position. Based on the engine rotational speed detected by the crank angle sensor, the throttle opening request value setting means for setting the throttle opening request value during engine operation, and the throttle opening sensor when the motor is in a non-energized state Whether the intermediate opening position holding mechanism is normal when the output actual throttle opening value is within a predetermined range with respect to a preset reference value of the intermediate opening position, and the other is abnormal. An intermediate opening position holding mechanism abnormality detecting means for detecting whether the motor is abnormal, and a throttle actuality from the throttle opening sensor when the motor is in a non-energized state and the intermediate opening position holding mechanism abnormality detecting means has not detected an abnormality. An intermediate opening position learning means for learning the opening value as an intermediate opening position learning value, and a normal operation region based on the intermediate opening position learning value. The throttle opening set by the throttle opening required value setting means is obtained by obtaining an opening operating area, a second opening operating area that is a throttle fully closed area, and a third opening operating area that is a throttle fully open area. Opening range determining means for determining whether the required value corresponds to one of the first, second, and third opening operating areas, and the throttle opening set by the throttle opening required value setting means The opening degree determined by the opening area determining means so that the required value is equal to or less than a throttle opening speed limit value set in advance for each of the first, second, and third opening operation areas. The throttle opening command value setting means for limiting the speed according to the operating region and outputting the throttle opening command value, and the throttle opening value detected by the throttle opening sensor is the throttle opening value. Throttle opening feedback control means for performing feedback control of the throttle opening so as to coincide with the throttle opening command value output from the command value setting means, and outputting a motor drive duty value to the motor. Therefore, it is possible to improve the durability of the components, reduce the cost, and reduce the current consumption.

Embodiment 1 FIG.
An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing the configuration of a throttle control device for an internal combustion engine that controls the intake air amount of the engine according to Embodiment 1 of the present invention.
In FIG. 1, reference numeral 1 denotes an accelerator opening sensor (described as APS in FIG. 1) that detects the position of an accelerator pedal as an accelerator opening. Reference numeral 2 denotes an ECU (Electronic Control Unit) that performs various engine controls, including a throttle control that controls the intake air amount of an engine (not shown). The microcomputer 5 and the DC motor drive circuit 6 (driven in FIG. 1). Circuit and the like). Reference numeral 3 denotes a throttle actuator. The throttle actuator 3 includes a DC motor 31 (described as a motor in FIG. 1), a reduction gear 32, a throttle shaft 33, a throttle valve 34, and a throttle opening sensor (referred to as TPS in FIG. 1). ) 4 is provided.

  In the throttle actuator 3, the driving force of the DC motor 31 is transmitted to the throttle shaft 33 via the reduction gear 32, whereby the throttle valve 34 is driven and the amount of intake air to the engine is adjusted. The throttle opening sensor 4 detects the throttle valve position of the throttle valve 34 as the throttle opening. The detected throttle opening signal (throttle actual opening signal value) is A / D converted by an A / D converter (not shown) provided in the microcomputer 5 and is sent to the microcomputer 5 as a throttle opening voltage value VTPS. Is read. The throttle actuator 3 according to the first embodiment includes an intermediate opening position holding mechanism for holding the throttle valve 34 at the intermediate opening position when the DC motor 31 is not energized.

  The microcomputer 5 inputs the accelerator opening signal from the accelerator opening sensor (APS) 1 and A / D converts the accelerator opening signal by an A / D converter (not shown) provided inside, thereby obtaining the accelerator opening voltage. Read as value. Further, the microcomputer 5 inputs an engine rotation speed signal (not shown) from a crank angle sensor (not shown), and uses an intermediate opening position learning value output from an intermediate opening position learning means 57 of FIG. An opening-air flow rate characteristic is set as a reference value (a relationship between the opening voltage VTM and the air flow rate Q_M), a throttle opening request value corresponding to the engine speed signal is calculated, and the throttle opening request value and intermediate opening A throttle opening command value whose opening speed is limited with respect to the throttle opening request value is calculated in accordance with an opening operation region (described later) determined based on the degree position learning value. Further, the microcomputer 5 calculates the throttle opening F / B (feedback) control (for example, PID control) so that the actual throttle opening value input from the throttle opening sensor (TPS) 4 matches the throttle opening command value. To obtain a control signal (for example, a DUTY signal at the time of PWM drive), output it to the DC motor drive circuit 6, and drive the throttle valve 34 by supplying a desired current to the DC motor 31. Conventionally, the opening-air flow rate characteristic is set based on the throttle fully closed position, but in the present invention, the opening-air flow rate characteristic is set based on the intermediate opening position, so that the fully closed position is abutted. Learning is not necessary.

  FIG. 2 shows a control block in the microcomputer 5. In FIG. 2, 51 is a crank angle signal from a crank angle sensor (not shown) for detecting the engine speed, 52 is an accelerator opening signal (APS signal) from an accelerator opening sensor (APS) 1 for detecting an accelerator opening. ), 53 is a throttle opening request value setting means, 54 is a motor energization OFF signal indicating the energization OFF state (non-energization state) of the DC motor 31, and 55 is a throttle opening input from the throttle opening sensor (TPS) 4. Signal (TPS signal), 56 is an intermediate opening position holding mechanism abnormality detecting means, 57 is an intermediate opening position learning means, 58 is an opening area determining means, 59 is a throttle opening command value setting means, and 60 is a throttle opening degree. F / B (feedback) control means 61 is a drive DUTY value (DUT) output from the throttle opening F / B control means 60 to the DC motor 31. It is a signal).

  As shown in FIG. 2, the microcomputer 5 includes a throttle opening required value setting means 53, an intermediate opening position holding mechanism abnormality detecting means 56, an intermediate opening position learning means 57, an opening area determining means 58, The throttle opening command value setting means 59 and the throttle opening F / B control means 60 are configured.

  The throttle opening required value setting means 53 includes a crank angle signal 51 (engine speed) output from a crank angle sensor (not shown) and an APS signal 52 (accelerator opening) output from the accelerator opening sensor 1. A throttle opening request value VT_REQ required at the time of engine operation is set based on at least the characteristics of the throttle opening voltage and the air flow rate that are input and set in advance. FIG. 11 is a graph showing an example of the throttle opening voltage-air flow rate characteristic. In the example of FIG. 11, the correspondence relationship between the throttle opening voltage and the air flow rate is set with an intermediate opening position learning value described later as a reference value.

  The intermediate opening position holding mechanism abnormality detecting means 56 includes a motor energization OFF signal 54 (for example, a flag: 0 at OFF, 1 at ON) indicating a power OFF state of the DC motor 31, and a throttle opening sensor (TPS). 4 is inputted to the throttle opening signal (TPS signal) 55, and when it is determined that the motor energization is in the OFF state (non-energized state) based on the motor energization OFF signal 54, By determining whether or not the AD conversion value VTPS of the throttle opening signal (TPS signal) 55 is within a design tolerance (± E) with respect to the preset design reference value VTMR of the intermediate opening position, Whether or not the position holding mechanism is abnormal is detected. Specifically, if the AD conversion value VTPS is within the design tolerance, it is determined that the intermediate opening position holding mechanism is normal, otherwise it is determined as abnormal.

  The intermediate opening position learning means 57 includes a motor energization OFF signal 54 (for example, a flag: 0 at OFF, 1 at ON) indicating the energization OFF state of the DC motor 31, and a throttle from the throttle opening sensor (TPS) 4. When the opening degree signal (TPS signal) 55 and the abnormality detection signal from the intermediate opening position holding mechanism abnormality detecting means 56 are inputted, the intermediate opening position holding mechanism abnormality detecting means 56 detects no abnormality. And, when it is determined by the motor energization OFF signal 54 that the DC motor 31 is in the energization OFF state (non-energization state), the AD conversion value of the throttle opening signal (TPS signal) 55 from the throttle opening sensor 4 VTPS is learned as an intermediate opening position learning value VTM.

  The opening area determination means 58 receives the intermediate opening position learning value VTM learned by the intermediate opening position learning means 57 and the throttle opening requirement value VT_REQ set by the throttle opening requirement value setting means 53. The intermediate opening position learning value VTM learned by the intermediate opening position learning means 57 is used as a reference value, and a predetermined value A, a predetermined value B, a predetermined value C, or a predetermined value D is added to or subtracted from the reference value. The throttle opening request value VT_REQ set by the throttle opening request value setting means 53 is opened by comparing the adjusted opening position with the throttle opening request value VT_REQ set by the throttle opening request value setting means 53. It is determined whether it corresponds to the first opening operation region in which the speed limit is not required, or the second opening operation region or the third opening operation region in which the opening speed restriction is required.

  The throttle opening command value setting means 59 includes the throttle opening request value VT_REQ set by the throttle opening request value setting means 53 and the first, second, and third opening determined by the opening operation region determination means 58. The engine speed is input by the throttle opening required value setting means 53 according to the type of the first, second, and third opening operation areas determined by the opening operation area determining means 58. The throttle opening request value VT_REQ set according to the (engine operating state) is subjected to opening speed limitation, and is output as a throttle opening command value VT_CMD.

  The throttle opening F / B control means 60 includes a throttle opening command value VT_CMD from the throttle opening command value setting means 59 and a throttle actual opening signal VTPS (TPS signal) 55 from the throttle opening sensor (TPS) 4. And F / B control (for example, PID control) is calculated so that the actual throttle actual opening value VTPS (TPS signal) 55 matches the throttle opening command value VT_CMD, A drive DUTY value (DUTY signal) 61 is output.

  3 and 4 are diagrams schematically showing a force relationship acting on the throttle shaft 33 of the throttle actuator 3. In these figures, 35 is a return spring, 36 is an opener spring, 37 is a fully closed stopper position, 38 is a fully open stopper position, and 39 is an intermediate opening stopper position. Reference numerals 31 to 34 are the same as those shown in FIG.

  FIG. 3 shows the stop position of the throttle valve 34 by the urging force of the return spring 35 when the DC motor 31 is de-energized. When the DC motor 31 is de-energized, the torque generated by the DC motor 31 becomes zero, so that the DC motor driving force does not act on the throttle shaft 33 via the reduction gear 32. Although the biasing force F1 of the return spring 35 and the biasing force F2 of the opener spring 36 act on the throttle shaft 33, the relationship that the opener spring biasing force F2 is larger than the return spring biasing force F1 (opener spring biasing force F2>). Therefore, the throttle valve 34 stops at the intermediate opening stopper position 39. When the DC motor 31 is driven in the same direction as the return spring biasing force F1, the throttle valve 34 rotates to the fully closed stopper position 37 and stops against the opener spring biasing force F2. On the other hand, when the DC motor 31 is driven in a direction opposite to the return spring biasing force F1, the throttle valve 34 is rotated to the fully open stopper position 38 and stopped.

  FIG. 4 shows the throttle valve 34 driven in the fully closed direction by the DC motor 31 against the biasing force F2 of the opener spring 36. The DC motor driving force (= FM) and the biasing force of the return spring 35 (= The throttle valve 34 is stopped in the vicinity of the fully closed stopper position 37 due to the balance between the added value of F1) and the biasing force F2 of the opener spring 36. The position of the throttle valve 34 can be monitored by the output value of the throttle opening sensor (TPS) 4 connected to the throttle shaft 33.

  FIG. 5 shows the relationship between the actual throttle opening value (VTPS) output from the throttle opening sensor (TPS) 4 and the slot opening operating region. In FIG. 5, the intermediate opening position learning value VTM learned by the intermediate opening position learning means 57 is used as a reference value, and a predetermined value A (for example, 0.25 V) is subtracted from the intermediate opening position learning value VTM to the fully closed side. A region from the opening position VTM-A to the opening position VTM + B obtained by adding a predetermined value B (for example, 3.5 V) to the fully open side is defined as a first opening operation area. The first opening operation region is an opening operation region during normal engine operation. In the example of FIG. 1, the predetermined value A <predetermined value B, but this is not a limitation.

  Further, in FIG. 5, an opening position VTM-A obtained by subtracting a predetermined value A to the fully closed side from the intermediate opening position learned value VTM is similarly opened by subtracting a predetermined value C (for example, 0.3 V) to the fully closed side. The region up to the position VTM-C is defined as the second opening operation region. Here, it is assumed that the predetermined value A <the predetermined value C. The second opening operation region is a throttle fully closed region, and when the intake air amount to the engine during idle operation is excessively set due to the secular change of the flow rate characteristic of the throttle actuator, the throttle valve 34 is closed and the air is This is the opening operation region when the amount is reduced.

  Further, in FIG. 5, a predetermined value D (for example, 3.7 V) is added to the fully open side from an opening position VTM + B obtained by adding a predetermined value B (for example, 3.5 V) to the fully opened side from the intermediate opening position learned value VTM. The region up to the opening position VTM + D is set as the third opening operation region. Here, it is assumed that the predetermined value B <the predetermined value D. The third opening operation region is a throttle fully open region, and the air flow rate is a region where the throttle fully open flow rate is reached, and is an operation region when the throttle opening request value VT_REQ is set in this region.

  The lower limit value VTM-C of the opening operation region is the sensor output voltage value (for example, 0.5 V) when the throttle valve 34 stops at the fully closed stopper position 37, and the upper limit value VTM + D is the throttle valve 34 at the fully opened stopper position 38. This is the sensor output voltage value (for example, 4.5 V) when stopped. The intermediate opening position learning value VTM is a sensor output voltage value (for example, 0.8 V) when the throttle valve 34 stops at the intermediate opening stopper position 39 when the DC motor 31 is not energized.

  FIG. 6 shows an abnormality detection of the intermediate opening position holding mechanism in the motor energization OFF state immediately before energization of the DC motor 31 of the throttle actuator 3 immediately after turning on the key switch (IG SW) (not shown) of the engine. The processing flow of the abnormality detection of the means 56 and the intermediate opening position learning by the intermediate opening position learning means 57 is shown.

  As shown in FIG. 6, first, in step S1, it is determined whether or not the DC motor 31 of the throttle actuator 3 is in the energized OFF state (non-energized state), and the throttle opening F / B control is already performed in the energized ON state. In the case of, the processing is finished as it is. On the other hand, if it is determined that the motor energization is OFF, in step S2, the throttle actual opening value VTPS from the throttle opening sensor 4 is read every predetermined sampling period (for example, 2.5 ms), and the AD converter is read. AD conversion is performed (not shown) (step S2).

  Next, in step S3, the absolute value | ΔVTPS | of the difference value between the AD conversion value of the VTPS at the previous sampling and the AD conversion value of the VTPS at the current sampling is a predetermined value DV_R (for example, 20 mV) set in advance. By determining whether or not it is smaller, it is determined whether or not the throttle valve 34 is in a stopped state (step S3). If the throttle valve 34 is not in the stopped state (that is, | ΔVTPS | ≧ DV_R), the process returns to step S2 and waits for the stopped state of the throttle valve 34. As a result, the key switch is turned OFF and ON in a short time while the throttle valve 34 is being controlled to an arbitrary throttle opening position during engine operation, and the throttle valve 34 is being returned from the arbitrary opening position to the intermediate opening position. Detection of an abnormality in the intermediate opening position holding mechanism and learning of the intermediate opening position are prohibited, and erroneous detection of the intermediate opening position holding mechanism and erroneous learning of the intermediate opening position are prevented.

  On the other hand, if it is determined in step S3 that the throttle valve 34 is in a stopped state (| ΔVTPS | <DV_R), in step S4, the throttle actual opening value VTPS output from the throttle opening sensor 4 is set to the intermediate opening. It is determined whether or not the position is within a design tolerance E (eg, 0.1 V) range (VTMR-E <VTPS <VTMR + E) with respect to the position design reference value VTMR. If it is within the design tolerance, the intermediate opening degree holding mechanism is normal, so the intermediate opening position learning process (described in FIG. 7) is performed in step S5, and the retreat travel determination flag is cleared in step S6 (LH_F = 0). To do.

  On the other hand, if the actual throttle opening value VTPS is not within the design tolerance in step S4, an abnormality in the intermediate opening position holding mechanism is detected, and in step S7, the retreat travel determination flag is set (LH_F = 1) and processing is performed. End. Thereby, evacuation travel is performed.

  FIG. 7 shows a flow for restricting the intermediate opening position learning value update amount. The intermediate opening position learning value update amount is a difference (or an absolute value of the difference) between the intermediate opening position learning value of the previous learning value and the intermediate opening position learning value of the current learning value.

  As shown in FIG. 7, first, in step S20, it is determined whether or not the intermediate opening position learning flag is set (VTM_LN_F = 1). If the learning flag is cleared (VTM_LN_F = 0), the battery is removed. Since this is the first learning later, in step S23, the actual throttle opening value VTPS of the throttle opening sensor 4 is stored as the current intermediate opening position learning value VTM (n), and in step S24, the intermediate opening learning is performed. The flag is set (VTM_LN_F = 1), and the process ends.

  On the other hand, if the learning flag is set (VTM_LN_F = 1) in step S20, the previous intermediate opening position learning value VTM (n-1) and the throttle opening sensor 4 at the current intermediate opening position are determined in step S21. A difference from the actual throttle opening value VTPS is obtained, and it is determined whether or not the absolute value | VTM (n−1) −VTPS | of the difference is larger than a predetermined value REF1 (for example, 10 mV). If it is less than or equal to the predetermined value REF1, the intermediate opening position learning value is updated by the process of step S23. On the other hand, if it is larger than the predetermined value REF1 in step S21, the update amount of the learning value with respect to the previous intermediate opening position learning value VTM (n-1) is set in step S22 according to the increase / decrease (±) direction of the learning value. The current learning value VTM (n) is updated as VTM (n) = VTM (n−1) ± REF1 by limiting to the predetermined value REF1, and the process ends. This reduces the influence of learning value fluctuations due to noise or the like.

  8A and 8B show that the throttle opening command value setting means 59 corresponds to any throttle opening operation region with respect to the throttle opening request value VT_REQ output by the throttle opening request value setting means 53. Whether or not to limit the opening speed depending on the type of throttle opening operation area determined by the opening area determination means 58 (different from the first, second and third opening operation areas). The processing flow when judging and outputting the throttle opening command value VT_CMD is shown.

  As shown in FIG. 8A, first, in step S40, an engine speed (not shown) by a crank angle sensor, an accelerator opening signal by an accelerator opening sensor, and a water temperature sensor (not shown) for detecting the temperature of engine cooling water. The operating state of the engine is detected based on the value of the water temperature (not shown).

  In step S41, the throttle opening request value setting means 53 calculates the throttle opening request value VT_REQ based on the engine operating state, and uses the preset lower limit value VTM-C and upper limit value VTM + D of the throttle opening operation region. Limited and calculated. That is, if the throttle opening request value VT_REQ is between the lower limit value VTM-C and the upper limit value VTM + D, it is output as it is, and if the throttle opening request value VT_REQ value is smaller than the lower limit value VTM-C, Value VTM-C is output as throttle opening request value VT_REQ, and if the value of throttle opening request value VT_REQ is larger than upper limit value VTM + D, upper limit value VTM + D is output as throttle opening request value VT_REQ.

  Next, in step S42, the retreat travel flag that is set when an abnormality is detected in the intermediate opening position holding mechanism (see step S7 in FIG. 6) or when an opening F / B control abnormality is detected (see step S56 in FIG. 8B) is set. It is determined whether or not (LH_F = 1), and if the flag is set (LH_F = 1), a retreat travel process is performed in step S43 due to engine output restriction (for example, fuel cut), and the process ends. . As a result, safety during retreating is ensured.

  On the other hand, if the retreat travel flag is cleared (LH_F = 0) in step S42, the opening range determination means 58 uses the intermediate opening learning value VTM and the throttle opening request value VT_REQ after step S44. Then, the throttle opening operation region is determined, and the throttle opening command value VT_CMD is set.

  That is, in step S44, the throttle opening request value VT_REQ is compared with the lower limit value VTM + B of the third opening operation region to determine whether the throttle opening request value VT_REQ requires the third opening operation region ( If VTM + B <VT_REQ) is determined and the third opening operation region is requested, the previous throttle opening command value VT_CMD (n−1) reaches the throttle opening request value VT_REQ in step S45 (VT_REQ ≦ VT_CMD (n-1)) is determined, and if it has been reached, the previous throttle opening command value VT_CMD (n-1) and the current throttle opening command value VT_CMD (n) are set in step S49. The throttle opening request value VT_REQ is set, and if not reached, the process proceeds to step S46.

  In step S46, the initial processing in which the throttle opening request value VT_REQ is set from the first opening operation region or the second opening operation region to the third opening operation region is performed in the previous throttle opening command value VT_CMD (n -1) and the current throttle opening command value VT_CMD (n) are set to the lower limit value VTM + B of the third opening operation region, and the second and subsequent processes are performed in the previous throttle opening command value VT_CMD (n-1). Is substituted with the current throttle opening command value VT_CMD (n), and the current throttle opening command value VT_CMD (n) is added to the previous throttle opening command value VT_CMD (n-1) by a predetermined value DTH (for example, 25 deg / sec). Opening speed setting value) is set by limiting the opening speed so that the value becomes (VT_CMD (n) = VT_CMD (n−1) + DTH). Proceeds to the throttle opening degree F / B control process S51.

  On the other hand, when it is determined in step S44 that the throttle opening request value VT_REQ does not require the third opening operation region, the throttle opening request value VT_REQ and the upper limit value of the second opening operation region are determined in step S47. Compared with VTM-A, it is determined whether the throttle opening request value VT_REQ requires the second opening operation region (VT_REQ <VTM-A), and the second opening operation region is requested. If YES in step S48, it is determined in step S48 whether or not the previous throttle opening command value VT_CMD (n-1) has reached the throttle opening request value VT_REQ in the fully closed direction (VT_CMD (n-1) ≤VT_REQ). If so, in step S49, the current throttle opening command value VT_CMD (n-1) and the current throttle opening command value VT_CMD (n) are throttled. Torr Set opening demand value VT_REQ, if not reached flow proceeds to step S50.

  In step S50, the initial process in which the throttle opening request value VT_REQ is set from the first opening operation region or the third opening operation region to the second opening operation region is the previous throttle opening command value VT_CMD (n− 1) and the current throttle opening command value VT_CMD (n) are set to the upper limit value VTM-A of the second opening operation region, and the second and subsequent processes are performed in accordance with the previous throttle opening command value VT_CMD (n−1). ) Is substituted for the current throttle opening command value VT_CMD (n), and the current throttle opening command value VT_CMD (n) is added to the previous throttle opening command value VT_CMD (n−1) by a predetermined value DTH (for example, 25 deg / step opening speed setting value) is set by limiting the opening speed so as to be a value obtained by subtracting (sec_CMD (n) = VT_CMD (n−1) −DTH). Proceeds to the throttle opening degree F / B control process 51.

  On the other hand, if it is determined in step S47 that the throttle opening request value VT_REQ does not require the second opening operation region but the first opening operation region, the process proceeds to step S49. The throttle opening request value VT_REQ is set to the throttle opening command value VT_CMD (n), and the process proceeds to the throttle opening F / B control process in step S51 without restricting the opening speed.

  As shown in FIG. 8B, in step S51, throttle opening position feedback (F / B) control (for example, so as to make the throttle opening signal value VTPS detected by the throttle opening sensor 4 coincide with the throttle opening command value VT_CMD). A PID control) operation is performed to calculate a motor drive duty value M_D_DUTY, which is output to the motor drive circuit 6 and a desired current is passed through the DC motor 31 to drive the throttle valve 34.

  In step S52, an unexpected butt against the fully closed stopper position 37 or the fully opened stopper position 38 of the throttle valve 34 occurs during the throttle opening F / B control in the second opening operation region or the third opening operation region. When the abutting determination process (the processing flow is described with reference to FIG. 9) is performed and it is determined that the abutting to one of the stopper positions occurs, the first, second, and third The predetermined value C or the predetermined value D for setting the lower limit value VTM-C or the upper limit value VTM + D in the entire opening operation region is reset.

  In step S53 and subsequent steps, the throttle opening F / B control abnormality during the throttle opening F / B control is detected in the entire first, second, and third opening operation regions.

  In step S53, it is determined whether or not the absolute value | VT_CMD−VTPS | of the deviation between the throttle opening command value VT_CMD and the actual throttle opening value VTPS is larger than a predetermined value ER_R (for example, 0.2V). If it is below, the counter value of the second timer counter TM_CNT_B is set to a second predetermined value TM_CNT_RB (for example, 0.5 sec) in step S57, and the process ends.

  On the other hand, if the absolute value of the deviation is larger than the predetermined value ER_R in step S53, the second timer counter TM_CNT_B is down-counted (TM_CNT_B = TM_CNT_B-1) in step S54, and the counter value of the second timer counter TM_CNT_B in step S55. If the counter value is 0, the absolute value of the deviation between the throttle opening command value VT_CMD and the actual throttle opening value VTPS is the second value. Is greater than a predetermined threshold value ER_R (for example, 0.2V) for a second predetermined time period (for example, 0.5 sec), thereby detecting that the throttle opening F / B control is abnormal. In step S56, the retreat travel flag LH_F is set (LH_F = 1), and the process ends.

  In this way, in the second opening operation region and the third opening operation region, the throttle opening control state in which a deviation occurs between the throttle opening request value VT_REQ during engine operation and the throttle opening command value VT_CMD limited in opening speed. However, since the throttle opening F / B control abnormality is detected based on the deviation between the throttle opening command value VT_CMD and the actual throttle opening value VTPS, the detection accuracy can be improved.

  FIG. 9 shows an unexpected abutment of the throttle valve 34 against the fully closed stopper position 37 or the fully opened stopper position 38 during the throttle opening F / B control in the second opening operation region or the third opening operation region. 7 shows a flow of a fully-closed stopper position and a fully-opened stopper position butting determination process for checking whether or not they are not performed.

  First, in step S60, it is determined whether or not the absolute value of the motor drive duty value M_D_DUTY is greater than a first predetermined threshold value DUTY_R (for example, 95%). If the absolute value is equal to or less than the first predetermined threshold value DUTY_R, the first value is determined in step S67. The counter value of the timer counter TM_CNT_A is set to a first predetermined value TM_CNT_RA (for example, 1.0 sec), and the process ends. On the other hand, if it is determined in step S60 that the absolute value of the motor drive duty value M_D_DUTY is greater than a first predetermined threshold value DUTY_R (for example, 95%), the counter value of the first timer counter TM_CNT_A is counted down (TM_CNT_A) in step S61. = TM_CNT_A-1), it is determined in step S62 whether or not the counter value of the first timer counter TM_CNT_A is 0. If it is not 0, the process is terminated.

  On the other hand, when the counter value is 0 in step S62, the state where the absolute value of the motor drive duty value M_D_DUTY is greater than the first predetermined threshold value DUTY_R (for example, 95%) continues for the first predetermined time (for example, 1.0 sec). In this state, the throttle valve 34 is in the contact state with the fully closed stopper position 37 or the fully opened stopper position 38. Therefore, the throttle opening request value VT_REQ requests the second opening operating region (VT_REQ ≦ VTM−) in step S63. A) It is determined whether or not the throttle valve 34 is in contact with the fully closed stopper position 37, so that the lower limit value (VTM−) of the throttle opening operation region is determined in step S64. The predetermined value C for setting C) is adjusted to the intermediate opening learning value VTM and the slot in the abutting state against the fully closed stopper position 37. Setting a deviation between the actual throttle open angle value VTPS torr opening sensor 4 (C = VTM-VTPS) and back.

  On the other hand, if the throttle opening request value VT_REQ does not request the second opening operation region (VT_REQ ≦ VTM-A) in step S63, the third opening operation region is requested (VTM + B ≦ VT_REQ) in step S65. If the throttle valve 34 is in contact with the fully open stopper position 38, a predetermined value for setting the upper limit value (VTM + D) of the throttle opening operation region in step S66. D is set to the difference between the intermediate opening learning value VTM and the actual throttle opening value VTPS of the throttle opening sensor 4 in the abutting state against the fully open stopper position 38 (D = VTPS−VTM) In S67, the counter value of the first timer counter TM_CNT_A is set to the first predetermined value TM_CNT_RA (for example, 1.0 sec). To the end of the process.

  On the other hand, when the third opening operation region is not requested (VTM-B ≦ VT_REQ) in step S65, the first opening operation region is requested. In this region, the motor drive duty value M_D_DUTY is set. It is determined that it is a throttle opening F / B control abnormal state that the absolute value continues larger than the first predetermined threshold DUTY_R (for example, 95%) for the first predetermined time (for example, 1.0 sec). In step S68, the retreat travel flag LH_F is set (LH_F = 1), and the process ends.

  FIG. 10 shows the throttle opening request value VT_REQ in the engine operating state, the throttle opening command value VT_CMD for controlling the actual throttle opening of the throttle valve 34 of the throttle actuator 3, and the throttle opening sensor 4. FIG. 6 is an operation time chart showing a relationship among a detected actual throttle opening value VTPS, an intermediate opening position learning value VTM, and a first opening operation region, a second opening operation region, and a third opening operation region.

  When the throttle opening request value VT_REQ changes from the third opening operation region to the second opening operation region at time T1, the throttle opening command value VT_CMD limits the opening speed in the second opening operation region. At time T1, the previous throttle opening command value VT_CMD (n-1) = VT2 (= VTM-A) is set, and from there, the previous throttle opening command value VT_CMD (n-1) is set to a predetermined value DTH (for example, Set the current throttle opening command value VT_CMD (n) by limiting the opening speed with a value (VT_CMD (n) = VT_CMD (n−1) −DTH) obtained by subtracting 25 deg / sec opening speed setting value). The throttle opening F / B control is performed so that the throttle actual opening value VTPS matches the throttle opening command value VT_CMD (n). While the value VTPS is limited to a predetermined opening speed (for example, 25 deg / sec), the throttle opening command value VT_CMD is moved to the throttle opening request value VT_REQ and the throttle opening command value VT_CMD becomes the throttle opening request value at time T2. VT_REQ is reached.

  Next, when the throttle opening request value VT_REQ changes from the second opening operation region to the third opening operation region at time T3, the throttle opening command value VT_CMD limits the opening speed in the third opening operation region. Therefore, at time T3, the previous throttle opening command value VT_CMD (n-1) = VT3 (= VTM-B) is set, and from there, the previous throttle opening command value VT_CMD (n-1) is set to a predetermined value DTH. (For example, the opening speed setting value of 25 deg / sec) is added to the value (VT_CMD (n) = VT_CMD (n−1) + DTH) to limit the opening speed and set the current throttle opening command value VT_CMD (n). Then, the throttle opening F / B control is performed so that the throttle actual opening value VTPS matches the throttle opening command value VT_CMD (n). While the actual opening value VTPS is limited to a predetermined opening speed (for example, 25 deg / sec), the throttle opening command value VT_CMD is moved to the throttle opening command value VT_CMD at the time T4. The required value VT_REQ is reached.

  As described above, in the first opening operation region (opening operation region from VTMA to VTM + B) that is a normal opening operation region during engine operation, the opening speed limit is not applied to the throttle opening command value VT_CMD. The throttle actual opening value VTPS can be made to follow the throttle opening request value VT_REQ at high speed, and the second opening operation region (opening operation region from VTM-A to VTM-C) and the third opening operation region (VTM + B to VTM + D opening operation range), the throttle opening command value VT_CMD is limited to the opening speed, so that the throttle valve 34 is fully closed due to changes in the throttle opening and TPS output characteristics of the throttle actuator 3 over time. Even if an unexpected hit occurs at the position 37 or the fully open stopper position 38, the opening speed limit is applied. It is possible to ensure the durability of the components of the throttle drive shaft around. For this reason, even when a resin material is used as a component around the throttle drive shaft, there is no fear of parts destruction due to the unexpected contact of the throttle valve with the fully closed stopper position or the fully opened stopper position.

  As described above, according to the throttle control device for an internal combustion engine according to the first embodiment of the present invention, at least the accelerator opening detected by the accelerator opening sensor (APS) 1 and the engine speed detected by the crank angle sensor. TPS output value from throttle opening sensor (TPS) 4 when DC motor 31 is in a non-energized state, and throttle opening required value setting means 53 for setting a throttle opening required value during engine operation based on Is detected within the first predetermined value with respect to the reference value of the intermediate opening position, and the intermediate opening position holding mechanism abnormality detecting means 56 for detecting an abnormality of the intermediate opening position holding mechanism, and the DC motor 31 Is the intermediate opening position that learns the TPS output value as the intermediate opening position learning value when the intermediate opening position holding mechanism abnormality detection means 56 has not detected any abnormality. A learning means 57 and an opening area determination means 58 for determining a first opening operation area, a second opening operation area, and a third opening operation area based on a throttle opening request value based on the intermediate opening position learning value. And a throttle opening speed limit value preset in accordance with each opening operation area determined by the opening area determination means 58 with respect to the throttle opening request value set by the throttle opening request value setting means 53 Since the throttle opening command value setting means 59 for limiting the opening speed and outputting it as a throttle opening command value is provided below, it is easy to determine the abnormality of the intermediate opening position holding mechanism and learn the intermediate opening position. This eliminates the need for end-to-end stopper positions and fully-opened stopper positions, and improves the durability of the components around the throttle drive shaft. It is not necessary to flow a motor current, reducing battery consumption current. In addition, learning of the throttle valve butting to the throttle fully closed stopper position (including the throttle fully open stopper position) is not required, so it is necessary for the throttle fully closed stopper position and fully open stopper position abutting learning operation when the key switch is OFF. The self-shut relay (relay that supplies power to the ECU and the throttle actuator for a predetermined time after the key switch is turned off and is turned off after the predetermined time) becomes unnecessary, leading to low cost. Further, there can be obtained an effect that noise during throttle learning operation when the key switch is OFF (noise generated by the intermediate opening position stopper when the throttle valve operates across the intermediate opening position) is eliminated.

  Further, according to the throttle control device for an internal combustion engine according to the first embodiment of the present invention, the first opening operation region is set to the first fully open throttle side with the intermediate opening position learning value as a reference value. An area from the opening position where the predetermined value A is subtracted to the opening position where the second predetermined value B is added to the throttle fully open side, and the throttle opening command value setting means 59 is The throttle opening request value set by the throttle opening request value setting means 53 is set as the throttle opening command value without limiting the opening speed with respect to the throttle opening request value set by the throttle opening request value setting means 53. There is an effect that the actual opening can be followed with good response.

  Further, according to the throttle control device for an internal combustion engine according to the first embodiment of the present invention, the second opening operation region is set to the first predetermined value on the throttle fully closed side with the intermediate opening position learning value as a reference value. An opening operation region obtained by subtracting A and the third predetermined value C is used, and the third opening operation region is an opening operation region obtained by adding the second predetermined value B and the fourth predetermined value D to the throttle fully open side. In the second opening operation region and the third opening operation region, the throttle opening command value setting means 59 limits the opening speed limit to a predetermined value or less with respect to the throttle opening command value, and the throttle opening command value setting means 59 Since the command value is used, mechanical damage to the components around the throttle drive shaft when the throttle valve abuts against the fully closed stopper position or the fully opened stopper position is reduced, and the durability of the components is reduced. sex There is an effect of improving.

  Further, according to the throttle control device for an internal combustion engine according to the first embodiment of the present invention, the intermediate opening position learning means 57 sets the learning value update amount from the intermediate opening position learning value at the previous learning to a predetermined value or less. Therefore, there is an effect that the influence of erroneous learning due to noise or the like can be suppressed.

  In addition, according to the throttle control device for an internal combustion engine according to the first embodiment of the present invention, the opening degree determination means 58 is provided with the throttle opening F / B in the second opening action region or the third opening action region. When the state where the absolute value of the motor drive duty output value being controlled is equal to or greater than the predetermined value continues for the first predetermined time or longer, the throttle valve is abutted against the fully closed stopper position or the fully opened stopper position. The predetermined value C or the predetermined value D is corrected by the deviation between the intermediate opening position learning value and the TPS output value at the time of determining the abutting state to the fully closed stopper position or the fully opened stopper position. Further, it is possible to prevent an unexpected butting against the fully closed stopper position and the fully opened stopper position, and the effect of improving the durability of the components around the throttle drive shaft can be obtained.

  In addition, according to the throttle control device for an internal combustion engine according to the first embodiment of the present invention, the throttle opening F / B control means has the throttle opening command value in the first, second, and third opening operation regions. Since the throttle opening F / B control abnormality is detected based on the opening deviation between the throttle opening command value set by the setting means and the actual throttle opening value detected by TPS, the detection accuracy is improved and erroneous determination is made. There is an effect that it is possible to prevent both.

  According to the throttle control device for an internal combustion engine according to the first embodiment of the present invention, when an abnormality is detected by the intermediate opening position holding mechanism abnormality detecting means 56, or when the abnormality is detected by the throttle opening F / B control means 60. When detected, the engine output is suppressed by fuel cut or the like so as to perform the retreat travel, so that the safety is ensured.

  In the first embodiment, the throttle opening request value is set also in the third opening operation region on the fully open side. However, the present invention is not limited to this, and the setting to the third opening operation region is performed. You may make it prohibit.

1 is a schematic configuration diagram illustrating a schematic configuration of a throttle control device for an internal combustion engine according to a first embodiment of the present invention; 1 is a block diagram showing a configuration of a microcomputer 5 provided in a throttle control device for an internal combustion engine according to a first embodiment of the present invention. FIG. It is explanatory drawing which showed the throttle valve stop position at the time of the motor deenergization in the throttle control apparatus of the internal combustion engine concerning Embodiment 1 of this invention. It is explanatory drawing which showed the throttle valve operation position at the time of the engine idling in the throttle control apparatus of the internal combustion engine concerning Embodiment 1 of this invention. It is explanatory drawing which showed in a graph the relationship between the TPS output characteristic and opening operation area | region in the throttle control apparatus of the internal combustion engine concerning Embodiment 1 of this invention. 3 is a flowchart showing a flow of an intermediate opening position learning process by the throttle control device for an internal combustion engine according to the first embodiment of the present invention; 3 is a flowchart showing a flow of intermediate opening position learned value update amount restriction processing by the throttle control device for an internal combustion engine according to the first embodiment of the present invention; 3 is a flowchart showing a flow of throttle opening command value setting processing by the throttle control device for an internal combustion engine according to the first embodiment of the present invention; 3 is a flowchart showing a flow of throttle opening command value setting processing by the throttle control device for an internal combustion engine according to the first embodiment of the present invention; 3 is a flowchart showing a flow of a fully closed / fully opened stopper position butting determination process by the internal combustion engine throttle control apparatus according to the first embodiment of the present invention; 3 is a time chart showing a relationship between a throttle required opening value and a command opening value in the throttle control device for an internal combustion engine according to the first embodiment of the present invention. It is explanatory drawing which showed the relationship between the throttle opening voltage by the throttle control apparatus of the internal combustion engine concerning Embodiment 1 of this invention, and the air flow rate with the graph.

Explanation of symbols

  1 accelerator opening sensor, 2 ECU, 3 throttle actuator, 4 throttle opening sensor, 5 microcomputer, 6 DC motor drive circuit, 31 DC motor, 32 reduction gear, 33 throttle shaft, 34 throttle valve, 35 return spring, 36 opener Spring, 37 Fully closed stopper position, 38 Fully open stopper position, 39 Intermediate opening stopper position, 53 Throttle opening required value setting means 53, 56 Intermediate opening position holding mechanism abnormality detecting means, 57 Intermediate opening position learning means, 58 Opening range determination means, 59 throttle opening command value setting means, 60 throttle opening F / B control means.

Claims (7)

A throttle valve that adjusts the amount of intake air to the engine, a throttle opening sensor that detects the opening of the throttle valve and outputs an actual throttle opening value, a motor that drives the throttle valve, and a power supply to the motor When the throttle valve is not in operation, the throttle valve with an intermediate opening position holding mechanism that holds the throttle valve at the intermediate opening position and the throttle opening degree so that the actual throttle opening value detected by the throttle opening sensor matches the target value. A throttle control device for an internal combustion engine comprising a control unit for feedback control of the degree,
A crank angle sensor for detecting engine rotation speed;
An accelerator opening sensor for detecting the accelerator opening;
The control unit is
Based on the accelerator opening detected by the accelerator opening sensor and the engine rotation speed detected by the crank angle sensor, a throttle opening request value setting means for setting a throttle opening request value during engine operation;
When the actual throttle opening value output from the throttle opening sensor when the motor is in a non-energized state is within a predetermined range with respect to a preset reference value of the intermediate opening position, An intermediate opening position holding mechanism abnormality detecting means for detecting whether the intermediate opening position holding mechanism is normal or abnormal,
When the motor is in a non-energized state and the intermediate opening position holding mechanism abnormality detection means detects no abnormality, an actual opening value from the throttle opening sensor is learned as an intermediate opening position learning value. Degree position learning means,
Using the intermediate opening position learning value as a reference, a first opening operation region that is a normal operation region, a second opening operation region that is a throttle fully closed region, and a third opening operation region that is a throttle fully open region are An opening area determining means for determining whether the throttle opening request value set by the throttle opening request value setting means corresponds to the first, second, or third opening operation area. When,
The throttle opening request value set by the throttle opening request value setting means is less than or equal to a throttle opening speed limit value set in advance for each of the first, second, and third opening operation regions. A throttle opening command value setting means for limiting the speed according to the opening operation region determined by the opening region determination means and outputting as a throttle opening command value;
The throttle opening feedback control is performed so that the actual throttle opening value detected by the throttle opening sensor coincides with the throttle opening command value output from the throttle opening command value setting means. And a throttle opening feedback control means for outputting the motor drive duty value of the internal combustion engine. With the intermediate opening position learned value as a reference, the first opening operation range is a second predetermined value on the throttle fully open side from an opening position obtained by subtracting a first predetermined value A from the reference to the throttle fully closed side. The area up to the opening position where the value B is added,
The throttle opening command value setting means outputs the throttle opening command value as it is without performing the speed limitation on the throttle opening request value in the first opening operation region. Item 2. The throttle control device for an internal combustion engine according to Item 1. The second opening operation region is the first predetermined value on the throttle fully closed side from the opening position obtained by subtracting the first predetermined value A on the throttle fully closed side with reference to the intermediate opening position learned value. An area up to the opening position obtained by subtracting the third predetermined value C set to a value larger than the value A,
The third opening operation region is the second predetermined position B on the throttle fully open side from the opening position obtained by adding the second predetermined value B to the throttle fully open side with the intermediate opening position learned value as a reference. As a region up to the opening position where the fourth predetermined value D set to a larger value is added,
The throttle opening command value setting means outputs the throttle opening command value by performing the speed limitation on the throttle opening request value in the second opening operation region and the third opening operation region. The throttle control device for an internal combustion engine according to claim 1 or 2, characterized in that:   The intermediate opening position learning means is a learning value update amount that is a difference between the intermediate opening position learning value at the previous learning time and the intermediate opening position learning value at the current learning time when learning the intermediate opening position learning value. The throttle control device for an internal combustion engine according to any one of claims 1 to 3, characterized in that is limited to a predetermined value or less.   In the second opening operation region or the third opening operation region, the opening region determination unit has an absolute value of a motor drive duty value from the throttle opening feedback control unit equal to or greater than a first predetermined threshold value. When the state continues for the first predetermined time or more, it is determined that the throttle valve is in contact with the fully closed stopper position or the fully opened stopper position, and the third predetermined value C or the fourth predetermined value D is determined. The correction is made by a deviation between the learning value of the intermediate opening position and the actual opening value of the throttle by the throttle opening sensor at the time of determining the abutting state to the fully closed stopper position or the fully opened stopper position. Item 5. The throttle control device for an internal combustion engine according to any one of Items 1 to 4.   In the first, second and third opening operation regions, the throttle opening feedback control means is configured to control a throttle opening command value set by the throttle opening command value setting means and a throttle actual value by the throttle opening sensor. 6. A throttle opening feedback control abnormality is detected when a state in which an absolute value of a deviation from an opening value is equal to or greater than a second predetermined threshold continues for a second predetermined time. The throttle control device for an internal combustion engine according to any one of the above.   When the abnormality is detected by the intermediate opening position holding mechanism abnormality detection means or when the abnormality is detected by the throttle opening feedback control means, the engine output is suppressed to perform retreat travel. Item 7. The throttle control device for an internal combustion engine according to Item 6.

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