JP4539586B2 - Control device for internal combustion engine - Google Patents

Description

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

  In recent years, exhaust gas regulations for internal combustion engines have become increasingly strict. For this reason, diesel engines have also been improved with respect to intake and exhaust systems. For example, engine control with high response and high accuracy is performed by computerization of various actuators (throttle actuator, EGR device, etc.).

  In particular, in a DPF that collects PM in the exhaust of a diesel engine and purifies the exhaust, when a DPF regeneration process that burns and removes accumulated PM is performed, the temperature of the DPF needs to be kept constant, Highly responsive and highly accurate control is required for the provided throttle actuator. Further, when an abnormality occurs in the throttle actuator, it is necessary to detect the abnormality early.

  Normally, in the throttle valve opening control, the target throttle opening is calculated based on the operating state and the like, and feedback control is performed so that the actual throttle opening matches the target throttle opening. In such a case, conventionally, the deviation between the actual throttle opening and the target throttle opening is calculated under the expected driving condition, and an abnormality such as a follow-up abnormality of the actual throttle valve is detected based on the deviation ( For example, see Patent Document 1).

Here, comparing the throttle valve opening control between a gasoline engine and a diesel engine, in the gasoline engine, the throttle opening is successively changed to keep the excess air ratio of the mixture of gasoline and air constant. In the diesel engine, since the fuel injection amount is controlled, it is not necessary to sequentially change the throttle opening. Therefore, when the DPF regeneration process is not performed, such as when the amount of PM accumulated in the DPF is small, the throttle opening is often maintained at a constant opening (for example, a fully open state). In this case, there is no difference between the actual throttle opening and the target throttle opening even if sticking or foreign matter is caught, and at first glance, the throttle actuator is mistakenly recognized as normal. . In other words, there is a risk of erroneous detection when detecting abnormality of the throttle actuator.
JP 2005-188309 A

  The main object of the present invention is to provide a control device for an internal combustion engine that can suppress erroneous detection when detecting abnormality of an opening degree variable actuator provided in a gas passage.

According to the first aspect of the present invention, a throttle actuator that adjusts the opening of a throttle valve provided in the intake system of the diesel engine is provided . Also, by intentionally operating the control state of the throttle actuator to cause a change of the opening degree of the throttle valve to detect the abnormality of the throttle actuator on the basis of the behavior of the throttle valve during operation of the throttle actuator.

In short, the behavior (opening change) of the throttle valve when the control state of the throttle actuator is intentionally operated differs depending on whether the throttle actuator is normal or abnormal. Therefore, an abnormality of the throttle actuator can be detected. At this time, in the case of a throttle actuator in which the frequency of the throttle valve opening change is small, there is a risk of false detection if abnormality detection is performed under normal operating conditions. Since the operation is performed, the fear of erroneous detection can be solved. Further, since abnormality detection can be performed at a desired timing, abnormality detection can be performed early.

According to the second aspect of the present invention, the operation of the throttle actuator is feedback-controlled to make the actual opening of the throttle valve coincide with the target value, the target value of the throttle valve opening is forcibly changed, and the target value An abnormality of the throttle actuator is detected based on the behavior of the throttle valve when the feedback control is performed after the change. In this case, if an abnormality occurs in the throttle actuator, the actual opening cannot follow the target value after the target value of the throttle valve opening is changed. For this reason, it is possible to detect abnormality of the throttle actuator based on the deviation between the actual opening and the target value.

According to the third aspect of the invention, the energization amount for the throttle actuator is forcibly changed, and an abnormality of the throttle actuator is detected based on the behavior of the throttle valve after the energization amount is changed. In this case, if an abnormality occurs in the throttle actuator, even if the energization amount to the throttle actuator is changed, the throttle valve opening does not change correspondingly (or the change in opening becomes minute). Therefore, it is possible to detect abnormality of the throttle actuator.

In the invention described in claim 4, the throttle actuator, the structure in which a biasing means for biasing the throttle valve in a predetermined direction, the throttle valve opening against the urging force of the urging means by the control of the throttle actuator The control of the throttle actuator is stopped from the state of adjusting the throttle valve , and the abnormality of the throttle actuator is detected based on the behavior of the throttle valve when the control of the throttle actuator is stopped.

In this case, when the control (energization) to the throttle actuator is stopped, the throttle valve is originally operated in a predetermined direction by the urging force of the urging means. On the other hand, if an abnormality occurs in the throttle actuator, the throttle valve does not operate even after the control is stopped (or the throttle valve operation becomes minute). Therefore, it is possible to detect abnormality of the throttle actuator.

In the invention described in claim 5, in the configuration to set the control range of the throttle valve in a range narrower than the mechanical operating range in which the throttle valve is operable, upon failure detection of the throttle actuator, throttle valve within the control range The control is released from the state in which the opening degree is controlled.

If the control range of the throttle valve is narrower than the mechanical operating range of the throttle valve , the control stops even if the opening degree control is performed at the limit position of the control range (control full open or control full close) Accordingly, the opening change of the throttle valve can be expected by the urging force of the urging means. Therefore, abnormality detection of the throttle actuator can be performed properly.

According to the sixth aspect of the present invention, when a vehicle equipped with a diesel engine is decelerated, an intentional operation of the throttle actuator (operation by the operation means) and abnormality detection (abnormality detection based on the behavior of the throttle valve associated with the operation) Anomaly detection by means).

If the control state of the throttle actuator is intentionally operated during normal control of the diesel engine , the operation state of the diesel engine may be affected. For this reason, it is desirable to detect an abnormality of the throttle actuator when there is little or no influence even if the throttle valve opening degree does not affect the operating state of the diesel engine . Therefore, it is preferable that abnormality detection is performed when the vehicle is decelerated.

As a diesel engine, configuration in which an exhaust purification device in the exhaust gas system is considered. The present invention can be preferably applied to a de-Izeruenji down was Hiroshi. That is, in the diesel engine having the above-described configuration, the opening degree control of the throttle valve is performed during the regeneration process of the exhaust purification device. Then, the control state operation by the operation means and the abnormality detection by the abnormality detection means are performed on the throttle actuator.

For de Izeruenji down as described above, but concerns erroneous detection when detecting an abnormality in consequences under operation is caused by an abnormality detection performed intentional opening operation, concerns misdetection Can be eliminated.

(First embodiment)
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. In the present embodiment, an engine control system is constructed for a diesel engine that is an internal combustion engine. In this control system, an electronic control unit (hereinafter referred to as an ECU) is used as a center to control the fuel injection amount. We are going to carry out. First, an overall schematic configuration diagram of the engine control system will be described with reference to FIG.

  In the engine 10 shown in FIG. 1, a throttle actuator 12 is provided in the intake pipe 11, and a throttle valve 14 whose opening degree is adjusted by a motor 13 is provided in the throttle actuator 12. The throttle actuator 12 includes a throttle opening sensor 15 for detecting the throttle opening. In the throttle actuator 12, when the motor 13 is not energized, the throttle valve 14 is held at a predetermined fully open position (machine fully opened position) by the urging force of a spring (not shown). The opening of the throttle valve 14 is adjusted against this.

  An intake valve 21 and an exhaust valve 22 are respectively provided at the intake port leading to the intake pipe 11 and the exhaust port leading to the exhaust pipe 17, and the air-fuel mixture is made to be in the combustion chamber 23 by the opening operation of the intake valve 21. The exhaust gas after being burned is introduced into the exhaust pipe 17 by the opening operation of the exhaust valve 22. An electromagnetically driven fuel injection valve 24 for supplying and supplying fuel is attached to the combustion chamber 23.

  The exhaust pipe 17 is provided with a DPF (diesel particulate filter) 31 for collecting PM in the exhaust. An A / F sensor 32 is provided on the downstream side of the DPF 31 to detect the oxygen concentration (hereinafter referred to as exhaust O2 concentration) using exhaust as a detection target.

  The intake pipe 11 is provided with an air flow meter 35 for detecting the amount of intake air sucked through the most upstream air cleaner (not shown). In addition, this control system is provided with a rotation speed sensor 38 that detects the rotation speed of the engine 10 and an accelerator sensor 39 that detects the amount of depression of the accelerator pedal (accelerator opening) by the driver.

  The engine 10 is provided with an EGR device for recirculating a part of the exhaust gas to the intake system as EGR gas. As an EGR device, an EGR pipe 41 is provided between the intake pipe 11 and the exhaust pipe 17, and an EGR valve 42 formed of an electromagnetic valve or the like is provided in the EGR pipe 41. By adjusting the opening degree of the EGR valve 42, the exhaust amount (EGR amount) recirculated to the intake system through the EGR pipe 41 is adjusted. That is, the intake air amount sucked into the intake port of the engine 10 is adjusted.

  The ECU 50 is an electronic control unit including a known microcomputer including a CPU, a ROM, a RAM, and the like, and the detection signals of the various sensors described above are sequentially input to the ECU 50. The ECU 50 executes various control programs stored in the ROM, thereby appropriately performing fuel injection control of the fuel injection valve 24 according to the engine operating state. That is, the ECU 50 determines the optimum fuel injection amount and injection timing based on engine operation information such as the engine rotation speed and the accelerator operation amount detected from various sensors, and drives the fuel injection valve 24 by an injection control signal corresponding thereto. To control.

  Further, the ECU 50 performs throttle control for controlling the intake air amount by adjusting the opening of the throttle valve 14 (hereinafter referred to as throttle opening). In the throttle control, the ECU 50 calculates the target value of the intake air amount based on, for example, the exhaust O2 concentration detected by the A / F sensor 32, and sets the target throttle opening. Then, the motor 13 is operated by a control command signal based on the target throttle opening, and the actual throttle opening detected by the throttle opening sensor 15 is matched with the target throttle opening.

  Here, basic control of throttle control will be described. FIG. 2 is a flowchart showing the throttle control process.

  In FIG. 2, in step S101, it is determined whether the DPF regeneration process is in progress. In the DPF 31, the collected ability of DPF is regenerated by burning and removing the accumulated PM. This DPF regeneration process is executed by controlling the temperature of the DPF. When the DPF regeneration process is being performed, the process proceeds to step S102, and it is determined whether or not the feedback control execution condition is satisfied. For example, it is assumed that the engine rotation speed and the fuel injection amount are used as parameters, and the feedback control execution condition is satisfied unless the engine is in a transient operation state. If YES in step S102, the process proceeds to step S103, and feedback control of the throttle opening is performed. That is, by controlling the throttle opening during the DPF regeneration process, the amount of air flowing through the DPF is adjusted to assist the DPF temperature control. At this time, feedback control is performed using a technique such as PID control so that the actual throttle opening becomes the target throttle opening. Thereby, the throttle actuator 12 is controlled with high response and high accuracy, and the DPF regeneration process is properly executed. Further, if either step S101 or step S102 is NO, the process proceeds to step S104, and throttle opening control is performed.

  In a diesel engine, throttle control is performed as described above. That is, during normal control, feedback control of the fuel injection amount is performed based on the engine operating state, so the frequency of change of the intake air amount is small. For this reason, the target throttle opening is often kept constant, and the throttle opening is controlled open. The target throttle opening is kept fully open, for example.

  By the way, it is conceivable that the throttle valve 14 does not operate properly when an abnormality such as sticking or foreign object biting occurs in the throttle actuator 12. Specifically, since the EGR gas recirculated by the EGR device contains PM (particulate matter), unburned gas, and the like, when these fuel components adhere to the throttle actuator 12, the throttle valve 14 May slow down or become stuck and stop working. Here, when the throttle valve 14 is stuck, the intake air amount is made constant. At this time, for example, when the DPF regeneration process is executed, the temperature of the DPF cannot be maintained properly, so that PM is not sufficiently removed by combustion. For this reason, PM accumulates excessively in the DPF, and there is a possibility that inconveniences such as a decrease in PM collection ability and a DPF breakage may occur.

  Therefore, the control state of the throttle actuator 12 is intentionally operated so as to cause a change in the opening of the throttle valve 14. That is, the target throttle opening is forcibly changed and the throttle valve 14 is operated. Thereby, the abnormality of the throttle actuator 12 can be detected based on the behavior of the throttle valve 14. Further, since the throttle valve 14 is forcibly operated, abnormality detection can be performed as necessary even when the throttle opening is often kept constant. Therefore, erroneous detection can be suppressed even in a state where the throttle actuator 12 is erroneously detected during normal control of the throttle opening, such as a state where the throttle valve 14 is fixed at the same opening as the target throttle opening.

  By the way, even when the target throttle opening changes sequentially, such as during throttle control, the actual throttle opening relative to the target throttle opening is low if the target throttle opening coincides with the actual throttle opening for a short period of time. Cannot be monitored correctly. Therefore, there are few opportunities to correctly detect the abnormality of the throttle actuator 12.

  FIG. 3 shows a flowchart of the abnormality detection process of the throttle actuator 12. This process is repeatedly executed by the ECU 50 at a predetermined time period.

  In FIG. 3, in step S <b> 201, it is determined whether an execution condition for detecting an abnormality of the throttle actuator 12 is satisfied. Specifically, when the engine is started, when the throttle control is stopped by fail-safe processing, or when the vehicle is suddenly accelerated or decelerated, this processing is terminated as it is because the condition for executing abnormality detection is not satisfied. For example, the throttle valve 14 during vehicle sudden acceleration / deceleration may move transiently. In this case, even if there is no abnormality in the throttle actuator 12, it is considered that the actual throttle opening does not follow the target throttle opening due to a response delay of the throttle valve 14 or the like. Therefore, the abnormality detection execution condition is not satisfied in order to suppress erroneous detection. On the other hand, if the engine operating state is not affected even if the throttle opening is changed or the influence is small, such as during deceleration of the vehicle, the condition for executing abnormality detection is satisfied, and the process proceeds to step S202. .

  In step S202, the target throttle opening is forcibly changed. For example, the target throttle opening is set to an opening of +5 degrees from the current actual throttle opening. This opening is an opening that does not affect the engine operating state, and may be an opening that takes into account variations in throttle control, such as an opening of ± 5% of the actual throttle opening. Then, the actual throttle opening is obtained from the throttle opening sensor 15, and feedback control of the throttle opening using a technique such as PID control is executed based on the deviation between the actual throttle opening and the target throttle opening.

  In step S203, it is determined whether or not a predetermined time has elapsed since the target throttle opening was changed. Since the actual throttle opening is made to follow the target throttle opening by feedback control of the throttle opening, a certain amount of time is required until the actual throttle opening matches the target throttle opening. For this reason, the predetermined time may be a time that takes into account the response delay time of the throttle valve 14 and the like. If the predetermined time has not elapsed, the process in step S203 is repeated until the predetermined time elapses. If the predetermined time has elapsed, the process proceeds to step S204.

  In step S204, it is determined whether or not the actual throttle opening (actual opening) matches the target throttle opening (target opening). In this case, it is preferable to consider the variation in feedback control. For example, if an allowable range is provided and the deviation of the throttle opening is within the allowable range, it is determined that the actual throttle opening matches the target throttle opening. If step S204 is YES, the process proceeds to step S205, where it is determined that the throttle actuator 12 is operating normally, and this process ends.

  When step S204 is NO, the process proceeds to step S206, and it is determined that an abnormality has occurred in the throttle actuator 12. If the actual throttle opening does not coincide with the target throttle opening within a predetermined time, it is determined that an abnormality has occurred in the throttle valve 14. At this time, even if an abnormality occurs not only in the throttle valve 14 but also in the motor 13 or the like, the abnormality can be detected based on the behavior of the throttle valve 14.

  In step S207, a fail safe process corresponding to the occurrence of an abnormality in the throttle actuator 12 is executed. As a result, the occurrence of other equipment or engine 10 failure due to the abnormality of the throttle actuator 12 is suppressed. An abnormality warning may be issued by lighting a warning lamp or the like.

  FIG. 4 shows the behavior of the throttle valve 14 when the abnormality detection process of the throttle actuator 12 is performed. In FIG. 4, (a) shows the change in the throttle opening at the normal time, and (b) and (c) show the changes in the throttle opening at the time of abnormality (at the time of abnormality 1 and 2 at the time of abnormality), respectively.

  Prior to timing t1, a target throttle opening is set based on each engine operating state, and feedback control for the target throttle opening is performed. After timing t1, abnormality detection processing is performed in accordance with the establishment of abnormality detection execution conditions. That is, at the timing t1, the target throttle opening is forcibly changed. At this time, if the throttle actuator 12 is normal, the actual throttle opening (actual opening) changes following the target throttle opening (target value), and the actual throttle opening becomes the target throttle opening at timing t2. Almost matches. Therefore, it is determined that the throttle actuator 12 is normal.

  On the other hand, when the throttle valve 14 does not operate due to sticking or the like (1 when there is an abnormality), the actual throttle opening does not change even if the target throttle opening is forcibly changed. At this time, since the throttle valve 14 does not operate, the opening degree is constant. Therefore, it is determined that the throttle actuator 12 is abnormal at the timing t2. Further, when the operation of the throttle valve 14 is slow (abnormal time 2), since the actual throttle opening does not follow the target throttle opening, the actual throttle opening does not coincide with the target throttle opening at timing t2. Therefore, it is determined that the throttle actuator 12 is abnormal.

  According to the embodiment described above in detail, the following excellent effects can be obtained.

  When the abnormality of the throttle actuator 12 is detected, the throttle valve 14 is operated by forcibly changing the target throttle opening. Thereby, the abnormality of the throttle actuator 12 can be detected based on the behavior of the throttle valve 14. At this time, since the throttle valve 14 is intentionally operated, even when the throttle opening is often kept constant in the throttle actuator 12, an abnormality can be detected at an early stage. Furthermore, erroneous detection can be suppressed when performing abnormality detection.

  After changing the target throttle opening, it is determined whether the actual throttle opening matches the target throttle opening within a predetermined period. For this reason, it is possible to detect a decrease in the followability of the actual throttle opening degree to the target throttle opening degree. By detecting a decrease in follow-up performance, the abnormality of the throttle actuator 12 can be detected.

  Abnormality detection is performed when the engine operating state is not affected even when the throttle opening degree is changed or when the influence is small, such as during deceleration of the vehicle, so that the throttle actuator 12 is not affected without affecting the vehicle running. Abnormality detection can be performed.

  Further, by detecting the abnormality of the throttle actuator 12, it is possible to suppress the occurrence of a failure of other equipment or the engine 10 caused by the abnormality of the throttle actuator 12, such as a damaged DPF.

(Second Embodiment)
In the first embodiment, the target throttle opening is forcibly changed during the feedback control of the throttle opening, and the abnormality is detected based on the response of the actual throttle opening at that time. In the second embodiment, however, The amount of current supplied to the throttle actuator 12 (motor 13) is forcibly changed, and abnormality detection is performed based on the response of the actual throttle opening at that time. The following description will focus on the differences from the first embodiment.

  FIG. 5 is a flowchart of the abnormality detection process of the throttle actuator 12 in the present embodiment. This process is executed by the ECU 50 instead of FIG. Note that FIG. 5 includes processing that overlaps that in FIG. 3 and steps S301, S303, S305 to S307, and the like are the same processing, so the description will be simplified.

  In FIG. 5, in step S301, it is determined whether or not an execution condition for detecting an abnormality of the throttle actuator 12 is satisfied. If the abnormality detection execution condition is not satisfied, the process is terminated. When the abnormality detection execution condition is satisfied, the process proceeds to step S302. In step S302, the energization amount for the throttle actuator 12 is forcibly changed. For example, an energization amount for obtaining an opening of +5 degrees from the current actual throttle opening is calculated. At this time, the characteristics of the amount of change in the throttle opening with respect to the energization amount may be defined in advance in a map or the like. Then, open control of the throttle opening is executed by changing the energization amount.

  In step S303, it is determined whether or not a predetermined time has elapsed since the target throttle opening was changed. If NO, the process in step S303 is repeated. If YES, the process proceeds to step S304. In step S304, it is determined whether or not the actual throttle opening coincides with a throttle opening corresponding to a change in the energization amount (hereinafter referred to as a command opening). In this case, it is preferable to consider variations in open control. For example, if an allowable range is provided and the deviation of the throttle opening is within the allowable range, it is determined that the actual throttle opening (actual opening) matches the command opening.

  If step S304 is YES, the process proceeds to step S305, where it is determined that the throttle actuator 12 is operating normally, and this process ends. When step S304 is NO, the process proceeds to step S306, where it is determined that an abnormality has occurred in the throttle actuator 12. In step S307, a fail safe process corresponding to the occurrence of an abnormality in the throttle actuator 12 is executed.

  FIG. 6 shows the behavior of the throttle valve 14 when the abnormality detection process of the throttle actuator 12 is performed. In FIG. 6, (a) shows the change in the throttle opening at the normal time, and (b) and (c) show the changes in the throttle opening at the time of abnormality (at the time of abnormality 1 and 2 at the time of abnormality), respectively. It is assumed that the throttle control is performed by feedback control outside the period during which the abnormality detection process is performed.

  At timing t11, the energization amount for the throttle actuator 12 is forcibly changed. At this time, if the throttle actuator 12 is normal, the actual throttle opening (actual opening) changes with the change in the energization amount, and the actual throttle opening substantially coincides with the command opening at timing t12. Therefore, it is determined that the throttle actuator 12 is normal. On the other hand, when the throttle valve 14 does not operate due to sticking or the like (when the abnormality is 1), the actual throttle opening does not change even if the energization amount is forcibly changed. When the operation of the throttle valve 14 is slow (abnormal time 2), since the actual throttle opening does not follow the command opening, the actual throttle opening does not coincide with the command opening at timing t12. Therefore, it is determined that the throttle actuator 12 is abnormal.

According to the second embodiment described in detail above, when the abnormality of the throttle actuator 12 is detected, the energization amount to the throttle actuator 12 is forcibly changed. For this reason, the throttle valve 14 operates and an abnormality of the throttle actuator 12 can be detected based on the behavior of the throttle valve 14.
(Third embodiment)
In the throttle actuator 12, stoppers are provided at the fully open position and the fully closed position of the throttle valve 14, and the throttle valve 14 can operate within a mechanical operation range defined by the stopper. The throttle valve 14 is urged in the fully open direction by a spring, and is adjusted to a desired opening degree by the throttle actuator 12 being electrically controlled by the ECU 50. At this time, the control range of the throttle valve 14 is narrower than the mechanical operation range.

  If it demonstrates using FIG. 7, as shown to (a), the mechanical full open position of the throttle valve 14 is M1, and a control full open position is S1. Further, as shown in (b), the mechanical fully closed position of the throttle valve 14 is M2, and the control fully closed position is S2. For example, the mechanical operation range (M1 to M2) is 0 to 90 degrees, and the control range (S1 to S2) is 5 to 80 degrees.

  Since the control range is narrower than the mechanical operation range, contact between the throttle valve 14 and the stopper can be prevented during normal throttle control. Thereby, wear at the contact portion between the throttle valve 14 and the stopper can be prevented. Further, in the throttle actuator 12, abnormal wear of a mechanism such as a gear for operating the throttle valve 14 can be suppressed.

  In the present embodiment, the throttle valve 14 is forcibly operated by the biasing force of the spring by forcibly stopping the energization of the throttle actuator 12. And abnormality detection is implemented by the response of the actual throttle opening at that time.

  FIG. 8 shows a flowchart of the abnormality detection process of the throttle actuator 12 in the present embodiment. This process is executed by the ECU 50 instead of FIG. Note that FIG. 7 includes the same processing as that in FIG. 3, and steps S401, S403, S405 to S407, and the like are the same processing, so the description will be simplified.

  In FIG. 8, in step S401, it is determined whether or not an execution condition for detecting the abnormality of the throttle actuator 12 is satisfied. If the abnormality detection execution condition is not satisfied, the present process is terminated. If the abnormality detection execution condition is satisfied, the process proceeds to step S402. In step S402, energization of the throttle actuator 12 is forcibly stopped. As a result, the throttle valve 14 is operated to the fully open position by the urging force of the spring. In step S403, it is determined whether or not a predetermined time has elapsed since the energization of the throttle actuator 12 was stopped. If NO, the process in step S403 is repeated. If YES, the process proceeds to step S404.

  In step S404, it is determined whether or not the actual throttle opening (actual opening) coincides with the fully opened mechanical opening. In the case of YES determination, the process proceeds to step S405, where it is determined that the throttle actuator 12 is operating normally, and this process ends. In the case of NO determination, the process proceeds to step S406, and it is determined that an abnormality has occurred in the throttle actuator 12. In step S407, fail safe corresponding to the occurrence of an abnormality in the throttle actuator 12 is executed.

  FIG. 9 shows the behavior of the throttle valve 14 when the abnormality detection process of the throttle actuator 12 is performed. In FIG. 9, (a) shows the change in the throttle opening at the normal time, and (b) and (c) show the changes in the throttle opening at the time of abnormality (at the time of abnormality 1 and 2 at the time of abnormality), respectively. It is assumed that the throttle control is performed by feedback control outside the period during which the abnormality detection process is performed.

  At timing t21, the energization to the throttle actuator 12 is stopped. At this time, if the throttle actuator 12 is normal, the actual throttle opening (actual opening) changes due to the urging force of the spring as the energization is stopped, and the actual throttle opening becomes the machine full opening (mechanical full opening) at timing t22. ). Therefore, it is determined that the throttle actuator 12 is normal. On the other hand, when the throttle valve 14 does not operate due to sticking or the like (when the abnormality is 1), the actual throttle opening does not change even when the energization to the throttle actuator 12 is stopped. Further, when the operation of the throttle valve 14 is slow (abnormal time 2), the actual throttle opening does not change at the timing t22 because the change in the actual throttle opening is gentle.

  According to the third embodiment described in detail above, the energization of the throttle actuator 12 is forcibly stopped when the abnormality of the throttle actuator 12 is detected. Therefore, the throttle valve 14 is operated by the biasing force of the spring, and an abnormality of the throttle actuator 12 can be detected based on the behavior of the throttle valve 14.

  In the throttle valve 14, the control range is set to be smaller than the mechanical operation range. For this reason, by operating the throttle valve 14 by the biasing force of the spring, it is possible to detect an abnormality within a mechanical operation range that cannot be detected by electrical control. Further, during normal throttle control, it is possible to suppress wear of the contact portion of the throttle valve 14 and the stopper, the movable mechanism portion of the throttle actuator 12, and the like.

  In addition, this invention is not limited to the content of description of the said embodiment, For example, you may implement as follows.

  In the first embodiment, after the target throttle opening is changed, the abnormality of the throttle actuator 12 is determined based on the opening deviation when a predetermined time elapses. After the change, the abnormality of the throttle actuator 12 may be determined based on the change speed of the actual throttle opening (a differential value of the actual throttle opening, etc.) and the time required to converge to the target throttle opening. Similarly, in the second embodiment, after the energization amount to the throttle actuator 12 is changed, the abnormality of the throttle actuator 12 is determined based on the change speed of the actual throttle opening and the time required to converge to the command opening. You may do it. Furthermore, even in the third embodiment, after the energization of the throttle actuator 12 is stopped, the abnormality of the throttle actuator 12 is determined based on the change speed of the actual throttle opening and the time required until the mechanical opening is converged. You may judge.

  An abnormality detection of the throttle actuator 12 according to each of the above embodiments may be performed together. For example, abnormality detection (first embodiment) performed by forcibly changing the target throttle opening and abnormality detection (third embodiment) performed by forcibly stopping energization of the throttle actuator 12 Form). In this case, if it is determined that the throttle actuator 12 is normal when the target throttle opening is changed and it is determined that the throttle actuator 12 is abnormal when the throttle actuator 12 is de-energized, it is considered that the abnormality is caused by the spring. Therefore, the abnormality of the spring can be detected by performing these abnormality detections together. Further, an abnormality detection (second embodiment) performed by forcibly changing the energization amount for the throttle actuator 12 and an abnormality detection performed by forcibly stopping the energization of the throttle actuator 12 (third Embodiment) may be performed together.

  In each of the above-described embodiments, the throttle actuator 12 is the one that the throttle valve 14 is urged by the spring and stops at the fully open position (normally open type). What stops at a closed position (normally closed type) may be used.

  In each of the above embodiments, the present invention is applied to the throttle actuator 12 provided in the intake pipe 11, but the present invention is not limited to this. For example, an actuator having a valve body provided in a gas passage such as an EGR device may be used. In particular, a valve body with a low operating frequency is considered to be useful in applying the present invention.

It is a block diagram which shows the outline of the engine control system in this Embodiment. It is a flowchart which shows a throttle control process. It is a flowchart which shows the abnormality detection process of a throttle actuator. It is a time chart which shows the behavior of a throttle valve. It is a flowchart which shows the abnormality detection process of the throttle actuator in 2nd Embodiment. It is a time chart which shows the behavior of the throttle valve in a 2nd embodiment. It is a figure which shows the movable range of the throttle valve in 3rd Embodiment. It is a flowchart which shows the abnormality detection process of the throttle actuator in 3rd Embodiment. It is a time chart which shows the behavior of the slot valve in a 3rd embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Intake pipe, 12 ... Throttle actuator, 13 ... Motor, 14 ... Throttle valve, 15 ... Throttle opening sensor, 31 ... DPF, 50 ... Operation means, ECU as abnormality detection means.

Claims (7)

A throttle actuator for adjusting the opening of a throttle valve disposed in an intake system of a diesel engine, the control device of Bei obtaining diesel engine and injects and supplies the fuel injection valves of fuel into the combustion chamber,
When the opening of the throttle valve does not affect the engine operating state or when the influence is small, and when the fuel injection control of the fuel injection valve is performed, the throttle valve An operating means for intentionally operating the control state of the throttle actuator to cause an opening change;
An abnormality detecting means for detecting an abnormality of the throttle actuator based on a behavior of the throttle valve when the throttle actuator is operated by the operating means;
A control device for a diesel engine , comprising: Feedback control of the operation of the throttle actuator in order to match the actual opening of the throttle valve with a target value;
While the operating means forcibly changes the target value,
2. The diesel engine according to claim 1, wherein the abnormality detection unit detects an abnormality of the throttle actuator based on a behavior of the throttle valve when the feedback control is performed after the target value is changed. Control device. The operating means forcibly changes the energization amount to the throttle actuator,
2. The diesel engine control device according to claim 1, wherein the abnormality detection unit detects an abnormality of the throttle actuator based on a behavior of the throttle valve after the energization amount is changed. The throttle actuator is provided with a biasing means for biasing the throttle valve in a predetermined direction,
It said operating means, while stopping the control of the throttle actuator from the state regulates the throttle valve opening against the urging force of the urging means by the control of the throttle actuator,
The diesel engine control device according to claim 1, wherein the abnormality detection means detects an abnormality of the throttle actuator based on a behavior of the throttle valve when the control of the throttle actuator is stopped. A control device for a diesel engine in which a control range of the throttle valve is set in a range narrower than a mechanical operation range in which the throttle valve is operable;
5. The diesel engine control device according to claim 4, wherein when the abnormality is detected by the abnormality detection unit, the operation unit releases the control from a state in which the throttle valve opening is controlled within the control range. Wherein during deceleration of a vehicle diesel engine is mounted, the control device for a diesel engine according to any one of claims 1 to 5 which comprises carrying out the abnormality detection by the abnormality detection means and operation by the operation means . Applies the exhaust gas purification device for diesel engine provided in the exhaust system, the control system for a diesel engine for implementing the control of the opening degree of the throttle valve upon regeneration process of the exhaust gas purifier,
7. The diesel engine control device according to claim 1, wherein an operation of a control state by the operation unit and an abnormality detection by the abnormality detection unit are performed on the throttle actuator. 7.

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