JP2013002344A - Throttle driving device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an engine output even if a throttle valve is continuously driven to open, resulting in a failure that a full open position is reached.SOLUTION: A position of a full open stopper 7 for limiting the aperture of the throttle valve 3 at a full open position is located such that the throttle valve 3 has the aperture for again narrowing a flow path of an intake pipe 2 beyond the aperture for fully opening the intake pipe 2. Thus, even if the throttle valve 3 is continuously driven to open, resulting in a failure that the full open position is reached, the engine output can be suppressed since the full open position is set at the position where the throttle valve 3 has the aperture to narrow the flow path of the intake pipe 2.

Description

  The present invention relates to a throttle drive device for an internal combustion engine in which a throttle valve provided in an intake pipe of the internal combustion engine is driven by a motor.

  As an example of the above-described throttle drive device for an internal combustion engine, one described in Patent Document 1 is known. In the device described in Patent Document 1, the target opening of the throttle valve is determined according to the depression amount of the accelerator pedal detected by the accelerator pedal sensor, and the detected opening of the throttle valve detected by the throttle opening sensor is determined. A motor connected through a throttle valve and a reduction gear is feedback-controlled by a duty signal so as to achieve the target opening.

  In the apparatus of Patent Document 1, a double sensor system in which two throttle opening sensors are provided in parallel is used to detect the throttle opening. In such a dual sensor system, for example, an abnormality occurs in the throttle opening sensor used for throttle valve feedback control (PID control), and the output value is closer to the target opening than the target opening. If it deviates, the DC motor connected to the throttle valve is driven to the open side in an attempt to eliminate the deviation.

  Here, the duty ratio of the duty signal for driving the DC motor is normally about 0% to 10%. However, as described above, when an abnormality occurs in the throttle opening sensor used for PID control, the output thereof Since the value does not follow the target opening, the duty ratio becomes larger than usual. Therefore, in the apparatus of Patent Document 1, an abnormality occurs in the throttle opening sensor used for PID control by monitoring the output difference between the two throttle opening sensors and the duty signal for driving the DC motor. Is detected. In this case, the throttle opening sensor used for PID control is switched to the remaining throttle opening sensor, not the throttle opening sensor in which an abnormality has occurred. In this way, normal PID control can be continuously executed using a normal throttle opening sensor.

JP-A-8-31435

  Here, in the apparatus of Patent Document 1 described above, when the output difference between the two throttle opening sensors is equal to or greater than a predetermined value and the duty ratio is close to the maximum value, the PID control is performed. It is determined that an abnormality has occurred in the throttle opening sensor used for.

  Thus, when an abnormality occurs in the throttle opening sensor, a predetermined time is required to determine the abnormality. Therefore, while this abnormality determination is being performed, the throttle valve is not opened until the PID control is newly started after the throttle opening sensor used for PID control is switched to a normal throttle opening sensor. To the full open position, and the engine output increases.

  The same applies to an abnormality other than the throttle opening sensor, such as an ECU as a control circuit or a motor drive circuit for driving a DC motor, which continues to drive the throttle valve to the open side. Problems arise.

  The present invention has been made in view of the above points, and can suppress engine output even when an abnormality occurs in which the throttle valve continues to be driven to the open side and reaches the fully open position. It is an object of the present invention to provide a possible internal combustion engine throttle drive device.

In order to achieve the above object, a throttle drive device for an internal combustion engine according to claim 1, wherein a throttle valve provided in an intake pipe of the internal combustion engine is driven by a motor,
There is a fully open stopper that restricts the opening on the fully open side of the throttle valve, and the position of the fully open stopper is such that the throttle valve exceeds the opening at which the intake pipe is fully opened and the flow of the intake pipe is narrowed again. It is characterized by being set to a position.

  By adopting such a configuration, even when an abnormality occurs in the sensor or control circuit such that the throttle valve continues to be driven to the open side and reaches the fully open position, the fully open position is Since the valve is set at a position where the opening of the intake pipe is throttled, the output of the internal combustion engine (engine) can be suppressed.

  According to a second aspect of the present invention, the abnormality detecting means for detecting the occurrence of an abnormality where the throttle valve contacts the fully open stopper, and when the occurrence of the abnormality is detected by the abnormality detecting means, the throttle valve is driven to the fully closed side. And a fail-safe means for executing at least one of a fuel injection cut and an ignition cut for the internal combustion engine at least until the throttle valve finishes passing through the opening position where the intake pipe is fully opened. preferable. As a result, when performing fail-safe processing for driving the throttle valve whose opening degree is limited by the fully open stopper to the fully closed side, the opening degree of the throttle valve becomes an opening degree that fully opens the intake pipe. However, it is possible to prevent the engine output from increasing.

  According to the third aspect of the present invention, it is preferable that the fail-safe means executes at least one of the fuel injection cut and the ignition cut for a predetermined period required until the throttle valve reaches the fully closed position. As a result, an increase in engine output can be reliably prevented during the fail-safe process for driving the throttle valve to the fully closed side.

1 is a schematic diagram showing an overall configuration of a throttle drive device for an internal combustion engine according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating a main configuration of a throttle drive device for the internal combustion engine of FIG. 1. It is explanatory drawing which shows the installation position of the conventional full open stopper. It is explanatory drawing which shows the installation position of the fully open stopper in embodiment. It is a flowchart which shows the control processing for performing feedback control of the opening degree of a throttle valve. It is a flowchart which shows the process sequence at the time of abnormality occurrence.

  Hereinafter, a throttle drive device for an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an overall configuration of a throttle drive device for an internal combustion engine according to the present embodiment. FIG. 2 is a block diagram showing the configuration of the main part of the throttle drive device for the internal combustion engine.

  1 and 2, reference numeral 2 denotes an intake pipe for supplying air to each combustion chamber of the internal combustion engine 1. A throttle valve 3 is provided in the middle of the intake pipe 2, and the amount of air supplied to each combustion chamber of the internal combustion engine 1 is adjusted by the opening of the throttle valve 3. The throttle valve 3 is provided with two throttle opening sensors 4A and 4B for detecting the throttle opening. Thus, in the present embodiment, a double sensor system including two throttle opening sensors 4A and 4B is employed as the throttle opening sensor. Although not shown, the intake pipe 2 is provided with an air flow meter that detects the amount of air flowing through the intake pipe 2. A detection signal from the air flow meter is input to an ECU 10 described later.

  An accelerator pedal 5 is provided with an accelerator pedal sensor 6 for detecting the amount of pedal depression. As the accelerator pedal sensor 6, a double sensor system may be adopted.

  Reference numeral 7 denotes a fully open stopper that regulates the fully open opening of the throttle valve 3. The fully open stopper 7 is engaged with a throttle gear 13 to be described later to limit the opening of the throttle valve 3 when the opening of the throttle valve 3 reaches a predetermined fully open position. Although not shown in FIGS. 1 and 2, a fully closed stopper for restricting the fully closed position of the throttle valve 3 is also provided. In addition to the engagement with the throttle gear 13, the fully open stopper 7 is engaged with the rotary shaft that connects the throttle gear 13 and the throttle valve 3, the throttle valve 3, etc. May be limited.

  Here, in the present embodiment, the full opening degree of the throttle valve 3 limited by the full opening stopper 7 described above is different from the conventional one.

  That is, conventionally, as shown in FIG. 3, the full-open stopper 7 is provided at a position corresponding to the opening degree at which the throttle valve 3 fully opens the intake pipe 2. However, in this case, if an abnormality occurs in the sensors 4A, 4B, the ECU 10, etc. so that the throttle valve 3 is continuously driven to reach the fully open position, the abnormality is detected and execution of fail-safe processing is started. In the meantime, the problem arises that the intake pipe 2 is opened to the maximum and the engine output increases.

  On the other hand, in the present embodiment, as shown in FIG. 4, the position of the fully open stopper 7 exceeds the opening degree at which the throttle valve 3 fully opens the intake pipe 2 and opens the flow path of the intake pipe 2 again. It is set to a position that will be degrees. For this reason, even when an abnormality occurs such that the throttle valve 3 continues to be driven to the open side and reaches the fully open position, in a time shorter than the time until the fail safe process is started in the conventional device, The increase in engine output ends, and then it becomes possible to suppress engine output.

  Reference numeral 12 denotes a DC motor as an actuator that rotationally drives the throttle valve 3. The DC motor 12 is a bidirectional rotation type DC motor, and rotates when a current is supplied by the motor drive circuit 11. The motor drive circuit 11 energizes the DC motor 12 with a current corresponding to a motor drive signal (duty signal) output from the ECU 10 described later.

  However, as will be described later, the throttle valve 3 always receives an urging force from the return spring 14, and even if only the opening degree of the throttle valve 3 is maintained, an electric current (only enough for the urging force by the return spring 14 ( It is necessary to energize the DC motor 12 with a holding duty signal. Therefore, when the energization of the DC motor 12 is turned off or a duty signal having a duty ratio smaller than the holding duty signal is given, the DC motor 12 rotates so that the throttle valve 3 is directed toward the closing side.

  The DC motor 12 is provided with a current sensor that detects an energization current, and a detection signal from the current sensor is also input to the ECU 10.

  A throttle gear 13 is connected to the throttle valve 3, and a motor gear 15 is connected to the DC motor 12. The throttle gear 13 and the motor gear 15 serve as a reduction gear, and reduce the rotation of the DC motor 12 and transmit it to the throttle valve 3. Reference numeral 14 denotes a return spring that constantly urges the throttle valve 3 toward the fully closed position defined by the fully closed stopper. The return spring 14 causes the throttle valve 3 to return to the fully closed position when the DC motor 12 is not energized.

  Reference numeral 10 denotes an ECU (Electronic Control Unit), to which the throttle opening signals THA and THB from the throttle opening sensors 4A and 4B and the accelerator opening signal Ap from the accelerator pedal sensor 6 are input. . Based on these sensor signals, the ECU 10 performs feedback control (PID control) so that the opening degree of the throttle valve 3 becomes the target opening degree. Further, the ECU 10 executes a fail-safe process for forcibly driving the throttle valve 3 toward the closed side when an abnormality occurs such that the throttle valve 3 is continuously driven to the open side and reaches the fully opened position. .

  Here, feedback control of the opening degree of the throttle valve 3 executed by the ECU 10 will be described with reference to the flowchart of FIG. In the present embodiment, feedback control is performed using the throttle opening signal THA from the throttle opening sensor 4A out of the two throttle opening sensors 4A and 4B. The throttle opening signal THB from the throttle opening sensor 4B is mainly used to determine whether or not an abnormality has occurred in the throttle opening sensor 4A.

  In step S200, as shown in FIG. 2, the accelerator opening signal Ap from the accelerator pedal sensor 6 and the throttle opening signal THA from the throttle opening sensor 4A are converted into A / D by the A / D converter 10a in the ECU 10. After being D-converted, it is taken into the ECU 10.

  In subsequent step S210, the ECU 10 calculates a throttle opening command value (target opening) θcmd based on the accelerator opening signal Ap from the accelerator pedal sensor 6. In step S220, it is determined whether or not the deviation between the throttle opening command value θcmd and the A / D converted throttle opening signal θA is 0 or more. If it is 0 or more, a duty signal with an increased duty ratio is calculated in step S230, and if it is less than 0, a duty signal with a decreased duty ratio is calculated in step S240. The duty ratio is calculated based on a deviation between the throttle opening command value θcmd and the throttle opening signal θA, and a predetermined P term gain Kp, I term gain Ti, and D term gain Td.

  Then, the ECU 10 outputs a motor drive signal having the calculated duty ratio to the motor drive circuit 11. The motor drive circuit 11 supplies a current corresponding to the motor drive signal to the DC motor 12. As a result, the DC motor 12 as a control target is rotationally driven so that the deviation between the throttle opening command value θcmd and the throttle opening signal θA is eliminated. Note that when feedback control of the opening degree of the throttle valve 3 is performed, PI control, PD control, or the like may be employed instead of PID control.

  Here, for example, during the execution of the feedback control described above, the throttle opening sensor 4A is short-circuited to a ground potential or a low potential, and the throttle opening signal θA, which is the output value, is obtained from the throttle opening command value θcmd. It is also assumed that an abnormality that adheres at a small value occurs. In this case, since the deviation between the throttle opening command value θcmd and the throttle opening signal θA is not eliminated, the calculated duty ratio increases. Therefore, the throttle valve 3 is driven toward the open side, and eventually the throttle valve 3 reaches the fully open position limited by the fully open stopper 7. Even in such a case, according to the present embodiment, as described above, the position of the fully open stopper 7 exceeds the opening degree at which the throttle valve 3 fully opens the intake pipe 2, and the flow path of the intake pipe 2 is again set. Since the opening is set at a position where the throttle is reduced, the engine output can be suppressed.

  When an abnormal state occurs in which the throttle valve 3 reaches the fully open position, in the present embodiment, when the occurrence of the abnormal state is detected, a fail-safe process for driving the throttle valve 3 toward the closed side is performed. Do. The flowchart of FIG. 6 shows a processing procedure for detecting the occurrence of an abnormal state and performing fail-safe processing. Hereinafter, the processing procedure shown in the flowchart of FIG. 6 will be described. Note that the process shown in the flowchart of FIG. 6 is repeatedly executed at predetermined time intervals.

  First, in step S300, the throttle opening signals THA and THB from the throttle opening sensors 4A and 4B are captured after A / D conversion by the A / D converter 10a.

  In the subsequent step S310, it is determined whether or not the result of subtracting the throttle opening signal θA from the throttle opening sensor 4A from the throttle opening signal θB from the throttle opening sensor 4B is larger than a predetermined amount α. At this time, if it is determined that it is larger than the predetermined amount α, the process proceeds to step S320, and if it is determined that it is not larger than the predetermined amount α, the process proceeds to step S340.

  In step S320, it is determined whether or not the duty ratio of the motor drive signal is larger than a predetermined value β (for example, 90%). In this determination process, if it is determined that the duty ratio is greater than the predetermined value β, the process proceeds to step S330. If it is determined that the duty ratio is equal to or less than the predetermined value β, the process proceeds to step S340.

  Here, in the throttle drive device of the present embodiment, as described above, the opening degree of the throttle valve 3 is feedback controlled based on the throttle opening degree signal THA (θA) detected by the throttle opening degree sensor 4A. The For this reason, if the throttle opening signal THA is fixed to a value smaller than the throttle opening command value θcmd due to some abnormality, the deviation from the throttle opening command value θcmd is eliminated even if feedback control is performed. It will be in a state that is not. As a result, the duty ratio of the motor drive signal increases and eventually the throttle valve 3 reaches the fully open stopper. The processing in steps S310 and S320 is for detecting the occurrence of such an abnormality.

  When occurrence of an abnormality is detected by the processing in steps S310 and S320, the abnormality counter A is incremented in step S330. This abnormality counter A is for counting the duration of the abnormal state determined in steps S310 and S320. Accordingly, if no abnormality is detected by the processes in steps S310 and S320, the count value of the abnormality counter A is cleared in step S340.

  In step S350, it is determined whether or not the count value of the abnormality counter A is equal to or longer than a predetermined time γ. If it is determined that the count value of the abnormality counter A is equal to or greater than the predetermined time γ, it is considered that an abnormal state has occurred in which the throttle valve 3 reaches the fully open position. Therefore, the process proceeds to the process of step S360 and the duty ratio of the motor drive signal is set to 0% to stop energization of the DC motor 12. As a result, a fail-safe process is performed in which the throttle valve 3 is driven from the fully open position defined by the fully open stopper 7 toward the fully closed side by the biasing force of the return spring 14.

  Here, in the throttle drive device according to the present embodiment, the fully opened position of the throttle valve 3 defined by the fully opened stopper 7 exceeds the opening degree with which the intake pipe 2 is fully opened, and the opening of the intake pipe 2 is narrowed again. It is set to a position that will be degrees. For this reason, when the fail-safe process described above is executed, the flow passage area of the intake pipe 2 increases to the maximum value while the throttle valve 3 is being driven, and then decreases to the minimum value. Therefore, if no countermeasure is taken, the engine output increases during the fail-safe process.

  Therefore, in the present embodiment, when performing the fail-safe process for driving the throttle valve 3 whose opening degree is limited by the fully open stopper 7 to the fully closed side, at least one of the fuel injection cut ignition cut is executed. did. Thereby, even if the opening degree of the throttle valve 3 becomes an opening degree at which the intake pipe 2 is fully opened, it is possible to prevent the engine output from increasing.

  Specifically, first, in step S370, the abnormality counter B is incremented. The abnormal counter B is cleared in step S380 until the count value of the abnormal counter A reaches a predetermined time γ. Therefore, the abnormality counter B counts the elapsed time after the fail sale process is started in step S360.

  In a succeeding step S390, it is determined whether or not the elapsed time counted by the abnormality counter B is shorter than 500 ms. The time of 500 ms is determined in consideration of the time required for the throttle valve 3 to reach the fully closed position from the fully open position regulated by the fully open stopper 7. If it is determined that the elapsed time counted by the abnormality counter B is shorter than 500 ms, at least one of the fuel injection cut and the ignition cut is executed in step S400. Thereby, it is possible to prevent the engine output from increasing while the throttle valve 3 is driven from the fully open position to the fully closed position by the fail-safe process.

  After the throttle valve 3 is driven to the fully closed position in this way, the throttle opening detected by the normal throttle opening sensor 4B is switched by switching the throttle opening sensor used for feedback control as in the prior art. Based on the above, the feedback control shown in FIG. 5 is continued.

  In addition, when abnormality occurs in the output from the ECU 10, not the throttle opening sensor 4A, or in the motor drive circuit 11 and the throttle valve 3 reaches the fully open position, the ECU 10 opens the throttle. The occurrence of an abnormality can be detected from the throttle opening detected by the degree sensors 4A and 4B. In this case, the ECU 10 executes a fail safe process for driving the throttle valve 3 to the fully closed position by setting the duty ratio of the motor drive signal to 0 or stopping the power supply to the motor drive circuit 11. At this time, as in the process of step S400, at least one of fuel injection cut and ignition cut is executed to prevent an increase in engine output. Thereafter, the ECU 10 controls the operating state of the engine so as to suppress the engine output to such an extent that the minimum retreat traveling can be performed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. .

  For example, in the above-described embodiment, a dual sensor system including two throttle opening sensors 4A and 4B is employed as the throttle opening sensor. However, the opening degree of the throttle valve 3 can be determined by using only one throttle opening sensor. May be detected.

  When only one throttle opening sensor is used, in order to detect an abnormality in which the output value of the throttle opening sensor is fixed at a value smaller than the throttle opening command value θcmd, the output of one throttle opening sensor is detected. The condition may be that the state in which the duty ratio of the motor drive signal is greater than the predetermined amount β continues for a predetermined time despite the change in the value being equal to or less than the predetermined value.

  In the above-described embodiment, the fuel injection cut and / or the ignition cut is performed to prevent the engine output from increasing while the throttle valve 3 is driven from the fully open position to the fully closed position by the fail-safe process. . However, from the viewpoint of suppressing an increase in engine output, a period from when driving of the throttle valve 3 in the fully open position is started until at least the throttle valve 3 finishes passing through the opening position where the intake pipe 2 is fully opened. The fuel injection cut and / or the ignition cut may be performed only for a time corresponding to.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 3 Throttle valve 4A, 4B Throttle opening sensor 5 Accelerator pedal 6 Accelerator pedal sensor 7 Full open stopper 10 ECU (electronic control unit)
10a A / D converter 12 DC motor

Claims (3)

In a throttle driving device for an internal combustion engine that drives a throttle valve provided in an intake pipe of the internal combustion engine by a motor,
A fully open stopper is provided to limit the opening of the throttle valve on the fully open side, and the position of the fully open stopper exceeds the opening at which the throttle valve fully opens the intake pipe, and the flow path of the intake pipe is throttled again. A throttle drive device for an internal combustion engine, wherein the throttle drive device is set at a position corresponding to an opening. An abnormality detecting means for detecting the occurrence of an abnormality in which the throttle valve is in contact with the fully open stopper;
When the occurrence of the abnormality is detected by the abnormality detection means, the throttle valve is driven to the fully closed side and at least the period until the throttle valve finishes passing through the opening position where the intake pipe is fully opened The throttle drive device for an internal combustion engine according to claim 1, further comprising fail-safe means for executing at least one of a fuel injection cut and an ignition cut for the internal combustion engine.   The throttle of an internal combustion engine according to claim 2, wherein the fail-safe means executes at least one of the fuel injection cut and the ignition cut for a predetermined period required until the throttle valve reaches a fully closed position. Drive device.

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