JP4683300B2 - Exhaust gas recirculation device - Google Patents

Description

  The present invention relates to an exhaust gas recirculation device for an internal combustion engine.

  Conventionally, an exhaust gas recirculation (EGR) device that recirculates exhaust gas flowing through an exhaust system of an internal combustion engine to an intake system is known. By performing EGR, NOx discharged from the internal combustion engine can be reduced. Such an EGR device includes a passage member that forms an EGR passage that connects an exhaust system and an intake system of the internal combustion engine. The EGR device has a valve member that opens and closes the EGR passage and controls the flow rate of the exhaust gas.

  The valve member is generally driven by an electric actuator. The valve member opens and closes the EGR passage by changing the electric power supplied to the actuator. Such an EGR device has an elastic member in order to ensure the operational stability of the internal combustion engine when the actuator malfunctions. The elastic member presses the valve member in a direction to fully close the EGR passage (refer to Patent Document 1 for a throttle valve having a similar configuration).

  By the way, when an abnormality such as bending occurs in the elastic member that presses the valve member, an increase in NOx in the exhaust gas and a deterioration in the operation performance of the internal combustion engine are caused. Therefore, conventionally, an abnormality of the elastic member is detected when the operation of the internal combustion engine is stopped. In this case, when the operation of the internal combustion engine is stopped, the actuator is energized to drive the valve member once to the open side, and then the energization to the actuator is stopped. Then, whether or not the valve member is returned to the closed side by the force of the elastic member is detected, and when the return of the valve member is small, it is determined that the elastic member is abnormal.

  However, when detecting an abnormality of the elastic member under the above-described conditions, even if an abnormality occurs in the elastic member, the internal combustion engine continues to operate with the abnormality in the elastic member until the operation of the internal combustion engine is stopped. Is done. Therefore, there is a problem in that the NOx in the exhaust gas is increased and the operability of the internal combustion engine is deteriorated from when the abnormality occurs in the elastic member until the operation of the internal combustion engine is stopped.

JP-A-5-231189

  Therefore, an object of the present invention is to provide an EGR device that detects an abnormality of an elastic member at an early stage.

  In the first aspect of the invention, the abnormality detection means opens and closes the valve member when the internal combustion engine is operated. The abnormality detection means detects an abnormality of the elastic member from the behavior of the valve member. By detecting the abnormality of the elastic member during the operation of the internal combustion engine, for example, even an abnormality of the elastic member caused during the operation of the internal combustion engine is detected. Therefore, the abnormality of the elastic member can be detected at an early stage, and NOx discharged from the internal combustion engine can be reduced and the operability of the internal combustion engine can be improved.

According to the first aspect of the present invention, the driving state detecting means detects the state of the vehicle on which the internal combustion engine is mounted. Then, when it is detected that the vehicle is decelerating, the abnormality detection means detects an abnormality of the elastic member. When detecting an abnormality of the elastic member during operation of the internal combustion engine, it is necessary to open and close the EGR passage by the valve member during operation of the internal combustion engine. However, depending on the operation state of the internal combustion engine, opening and closing of the EGR passage may cause deterioration of exhaust performance and deterioration of the stability of the internal combustion engine. On the other hand, when the vehicle decelerates, that is, when the rotational speed of the internal combustion engine decreases, the change in the performance of the internal combustion engine due to EGR is small. Therefore, in the first aspect of the invention , the abnormality of the elastic member is detected when the vehicle is decelerating. Therefore, even if the abnormality detection of the elastic member is performed during the operation of the internal combustion engine, it is possible to reduce the deterioration of the exhaust performance and the deterioration of the operability of the internal combustion engine.

In the first aspect of the invention, the abnormality detecting means drives the valve member to a preset opening degree if the valve member is fully closed when detecting the abnormality of the elastic member. The abnormality of the elastic member is detected by the behavior of the valve member when the force applied from the actuator to the valve member disappears by stopping energization to the actuator. Therefore, if the valve member is fully closed, the change in the opening degree of the valve member is small even when the energization to the actuator is stopped. Therefore, in the first aspect of the present invention, the valve member is driven to a preset opening degree. Thereby, the behavior of the valve member by the elastic member is detected. Therefore, it is possible to reliably detect abnormality of the elastic member.

In the invention according to claim 2, the abnormality detecting means detects abnormality of the elastic member from the stop of energization to the actuator and the opening degree of the valve member. When an abnormality occurs in the elastic member, the valve member does not operate to close the EGR passage even if the energization to the actuator is stopped. For this reason, the abnormality detection means determines that the elastic member is abnormal when the opening degree of the valve member is equal to or greater than a predetermined value even after a predetermined period has elapsed since the energization of the actuator was stopped. Therefore, it is possible to reliably detect abnormality of the elastic member.

In the invention according to claim 3 or 4, the abnormality detection means detects abnormality of the elastic member from the electric power supplied to the actuator. If the elastic member is normal, it presses the valve member in the direction to close the EGR passage. Therefore, if the elastic member is normal, when the valve member is driven in the opening direction, the actuator needs a lot of electric power to counter the pressing force of the elastic member. On the other hand, when an abnormality occurs in the elastic member, the force of the elastic member that presses the valve member in the direction to close the EGR passage decreases. Therefore, when the valve member is driven to a certain opening degree, the electric power supplied to the actuator becomes small. That is, the electric power consumed by the actuator changes when the valve member is driven to a certain degree of opening depending on whether or not the elastic member is abnormal. Therefore, the abnormality detection means detects the abnormality of the elastic member from the power supplied to the actuator. Therefore, it is possible to reliably detect abnormality of the elastic member.

The invention according to claim 5 is provided with power supply means. The power supply means changes the relationship between the opening of the valve member and the power supplied to the actuator. As described above, the actuator drives the valve member against the pressing force of the elastic member. Therefore, when an abnormality is detected in the elastic member, the valve member is normally driven by reducing the power supplied to the actuator. That is, when an abnormality is detected in the elastic member, the actuator normally drives the valve member by supplying electric power to the actuator without considering the pressing force of the elastic member and controlling the actuator. Therefore, for example, even before the elastic member is repaired, the deterioration of the exhaust performance and the deterioration of the operation performance of the internal combustion engine can be reduced.

The invention described in claim 6 is provided with warning means. The warning means warns the vehicle driver of abnormality of the elastic member. Thereby, the driver | operator of a vehicle can recognize abnormality of an elastic member at an early stage, and can repair or exchange an elastic member.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. In addition, in each embodiment, the same code | symbol is attached | subjected to the substantially same component, and description is abbreviate | omitted.
(First embodiment)
FIG. 2 is a schematic diagram showing a diesel engine system 10 to which the EGR device according to the first embodiment of the present invention is applied. The diesel engine system 10 is equipped with a common rail fuel injection device. The diesel engine system 10 includes an engine body 11 as an internal combustion engine, an intake system 20, an exhaust system 30, a fuel injection device 40, an EGR device 50, and a supercharging device 70. The diesel engine system 10 is controlled by an ECU 12 as a control device as shown in FIG. In the embodiment of the present invention, a diesel engine is described as an example of the internal combustion engine, but a gasoline engine may be used.

  The engine body 11 has a plurality of cylinders 13 as shown in FIG. The engine body 11 has a drive system such as a piston (not shown). The engine body 11 has an intake valve 14 and an exhaust valve 15. The intake valve 14 and the exhaust valve 15 are driven by valve drive means (not shown). The intake valve 14 interrupts the flow of intake air drawn from the intake system 20 into the cylinder 13. The exhaust valve 15 interrupts the flow of exhaust discharged from the cylinder 13 to the exhaust system 30. A valve drive means (not shown) drives the intake valve 14 and the exhaust valve 15 by rotation of a drive shaft (not shown) of the engine body 11.

  The intake system 20 includes an intake pipe 21, an intake manifold 22, and a throttle 23. The intake pipe 21 is connected to an air cleaner (not shown). A supercharging device 70 is provided in the middle of the intake pipe 21. The intake pipe 21 is connected to the intake manifold 22 at the end opposite to the air cleaner (not shown). The intake manifold 22 branches from the intake pipe 21 to each cylinder 13. The intake manifold 22 distributes air introduced from an air cleaner (not shown) to each cylinder 13. A throttle 23 is provided on the engine body 11 side of the supercharging device 70 of the intake pipe 21. The throttle 23 has a drive unit 24 and a valve member 25. The throttle 23 controls the flow rate of intake air supplied to the engine body 11 via the intake pipe 21. The drive unit 24 of the throttle 23 is connected to the ECU 12 as shown in FIG. The drive unit 24 drives the valve member 25 in accordance with a command from the ECU 12. The valve member 25 is a disk-shaped valve, for example, and opens and closes the intake pipe 21 by rotating. As shown in FIG. 2, an intercooler 26 is provided on the downstream side of the supercharging device 70 in the intake pipe 21. In the intercooler 26, the intake air whose temperature has been increased by being supercharged by the supercharging device 70 is cooled.

  The exhaust system 30 has an exhaust pipe 31 and an exhaust manifold 32. The exhaust pipe 31 is connected to a catalyst and a muffler (not shown). A supercharging device 70 is provided in the middle of the exhaust pipe 31. The exhaust pipe 31 is connected to the exhaust manifold 32 at the end opposite to the catalyst and the muffler (not shown). The exhaust manifold 32 connects each cylinder 13 and the exhaust pipe 31.

  The fuel injection device 40 includes a fuel injection pump 41, a common rail 42, and an injector 43. The fuel injection pump 41 is driven by the driving force transmitted from the engine body 11. The fuel injection pump 41 pressurizes fuel sucked from a fuel tank (not shown) to a predetermined pressure, and then supplies the fuel to the common rail 42. The common rail 42 stores fuel at a predetermined pressure, that is, in a pressure accumulation state. The injector 43 is provided in each cylinder 13. The injector 43 is connected to the common rail 42 and injects high-pressure fuel supplied from the common rail 42 into the cylinder 13. The injector 43 has a solenoid valve. The solenoid valve of the injector 43 intermittently injects fuel according to a command from the ECU 12. When the solenoid valve of the injector 43 is energized from the ECU 12 at a predetermined time, high pressure fuel is injected from the injector 43 to the cylinder 13.

  The supercharging device 70 is a variable turbocharger such as a VN (Variable Nozzle) turbo capable of changing the supercharging pressure. The supercharging device 70 includes a turbine 71, a compressor 72, and a turbo actuator 73. The turbine 71 is provided in the middle of the exhaust pipe 31 and is rotationally driven by the flow of exhaust gas flowing through the exhaust pipe 31. The compressor 72 is provided in the middle of the intake pipe 21. The compressor 72 is rotationally driven by the rotation of the turbine 71 and supercharges the intake air flowing through the intake pipe 21. The turbo actuator 73 changes the clearance between the turbine 71 through which the exhaust gas flows and the container according to an instruction from the ECU 12, and controls the supercharging pressure of the intake air. The intake air supercharged by the compressor 72 of the supercharging device 70 is cooled by the intercooler 26 and then supplied to the cylinder 13 of the engine body 11.

  As shown in FIG. 1, the EGR device 50 includes a passage portion 51, a valve member 52, an actuator 53, a spring 54 as an elastic member, and an opening degree sensor 55 as an opening degree detecting means. The passage 51 branches from the exhaust pipe 31 upstream of the supercharger 70 in the exhaust flow direction, and is connected to the intake pipe 21 downstream of the supercharger 70 in the intake flow direction. The passage portion 51 forms an EGR passage 56. The EGR device 50 returns a part of the exhaust gas flowing through the exhaust pipe 31 to the intake air flowing through the intake pipe 21.

  The valve member 52 is provided in the middle of the passage portion 51. The valve member 52 is formed in a disk shape having a shaft 57 at the center. Thereby, the valve member 52 rotates in the circumferential direction around the shaft 57. The valve member 52 opens and closes the EGR passage 56 formed by the passage portion 51 by rotating around the shaft 57. Thereby, the flow rate of the exhaust gas recirculated from the exhaust system 30 to the intake system 20 is controlled. The shaft 57 has one end connected to the actuator 53 and the other end connected to the opening sensor 55. The actuator 53 has a motor that is driven when supplied with electric power. The actuator 53 is connected to the ECU 12. By supplying electric power from the ECU 12 to the actuator 53, the valve member 52 rotates together with the shaft 57 by the driving force from the actuator 53.

  A spring 54 is connected to the shaft 57 of the valve member 52. The spring 54 has one end connected to the shaft 57 of the valve member 52 and the other end connected to the passage portion 51. The spring 54 applies a force to the shaft 57 of the valve member 52 in a direction in which the valve member 52 closes the EGR passage 56. Thereby, when the force applied to the valve member 52 from the actuator 53 disappears, the valve member 52 rotates by the pressing force of the spring 54. The valve member 52 is pressed by a spring 54 in a direction to close the EGR passage 56. Therefore, when the force applied to the valve member 52 from the actuator 53 disappears, the valve member 52 is rotated by the pressing force of the spring 54 and closes the EGR passage 56. That is, the spring 54 is a return spring that pushes the valve member 52 back to the side where the EGR passage 56 that is the initial position is closed.

  The opening sensor 55 is provided at the end of the valve member 52 opposite to the actuator 53 of the shaft 57. The opening sensor 55 detects the rotation angle of the shaft 57. The rotation angle of the shaft 57 is correlated with the opening degree of the valve member 52, that is, the opening degree of the EGR passage 56 by the valve member 52. The opening sensor 55 outputs the detected rotation angle of the shaft 57 to the ECU 12 as an electrical signal.

  The ECU 12 performs overall control of the diesel engine system 10 such as the engine body 11, the intake system 20, the exhaust system 30, the fuel injection device 40, the EGR device 50, and the supercharging device 70. ECU12 is comprised from the microcomputer which has CPU, RAM, ROM etc., for example. The ECU 12 controls the entire diesel engine system 10 according to a computer program recorded in the ROM.

  As shown in FIG. 3, a battery 16, an input circuit, and an output circuit are connected to the ECU 12. The battery 16 supplies electric power to each part of the diesel engine system 10 via the ECU 12. That is, the ECU 12 also functions as power supply means. The ECU 12 receives signals from various sensors in the input circuit. Moreover, ECU12 outputs a signal to each part via an output circuit. A rotation speed sensor 81, an accelerator sensor 82, and an opening degree sensor 55 are connected to the input circuit. The rotation speed sensor 81 detects the rotation speed of a drive shaft (not shown) of the engine body 11. The accelerator sensor 82 detects the opening of an accelerator pedal (not shown). The rotation speed sensor 81 and the accelerator sensor 82 together with the ECU 12 constitute an operating state detection unit. The opening degree sensor 55 detects the opening degree of the valve member 52 of the EGR device 50 as described above.

  On the other hand, an electromagnetic valve of the injector 43, a drive unit 24 of the throttle 23, an actuator 53 of the EGR device 50, a turbo actuator 73 of the supercharging device 70, and the like are connected to the output circuit of the ECU 12. Further, a warning unit 83 as warning means is connected to the output circuit of the ECU 12. The warning unit 83 warns the vehicle occupant of the occurrence of an abnormality when an abnormality occurs in each part of the vehicle. The warning unit 83 can use, for example, a means for generating an audible warning by sound such as a buzzer or an alarm sound, or a means for generating a visual warning by lighting or blinking a lamp provided on the dashboard. .

  The ECU 12 determines the operating state of the engine body 11, the load state of the engine body 11, and the engine based on, for example, the accelerator opening detected by the accelerator sensor 82 and the rotation speed of the engine body 11 detected by the rotation speed sensor. The acceleration / deceleration state of the vehicle on which the main body 11 is mounted is detected. Further, the ECU 12 controls the fuel injection device 40, the EGR device 50, the supercharging device 70, and the like based on the detected operating state and load state of the engine body 11. The ECU 12 also functions as an abnormality detection unit that detects an abnormality of the spring 54 of the EGR device 50.

Next, abnormality detection of the EGR device 50 by the diesel engine system 10 having the above configuration will be described.
(Abnormality detection)
First, an abnormality detection procedure will be described based on the flowchart shown in FIG. 4 and the time charts shown in FIGS. 5 and 6.
When the diesel engine system 10 is in operation, the ECU 12 detects whether the engine body 11 is decelerating, that is, whether the vehicle on which the engine body 11 is mounted is decelerating (S101). In the first embodiment, the ECU 12 detects whether the EGR device 50 is abnormal even when the diesel engine system 10 is in operation. For example, the ECU 12 determines that the vehicle is decelerating when the accelerator sensor 82 detects that the accelerator pedal opening is 0% at the time t1 and the fuel injection instruction is not output to the injector 43. Note that the ECU 12 may be configured to determine that the vehicle is decelerating when the accelerator pedal opening is 0%. At a timing t2 when a predetermined period has elapsed after the accelerator pedal opening becomes 0 at the timing t1, the rotational speed of the engine body 11 starts to decrease. Further, for example, it may be determined whether or not the vehicle is decelerating, including changes in the vehicle speed detected by a vehicle speed sensor (not shown). When the ECU 12 determines that the vehicle is decelerating, the ECU 12 turns on the deceleration determination at timing t3. When the vehicle is not decelerating, the ECU 12 ends the abnormality detection.

When it is detected in step S101 that the vehicle is decelerating, the ECU 12 detects whether or not the valve member 52 of the EGR device 50 is fully closed (S102). The ECU 12 detects the opening degree of the valve member based on the electrical signal output from the opening degree sensor 55.
When the accelerator opening becomes zero at timing t1, the opening of the EGR device 50 may become zero. Therefore, when it is detected in step S102 that the valve member 52 of the EGR device 50 is fully closed, the ECU 12 supplies power to the EGR device 50 at timing t3 shown in FIG. Then, the ECU 12 drives the opening degree of the valve member 52 of the EGR device 50 to a predetermined target value α (S103). As shown in FIG. 7, the ECU 12 has a relationship between the opening degree of the valve member 52 of the EGR device 50 and the power supplied to the actuator 53 as a map. Therefore, the ECU 12 supplies predetermined power to the actuator 53 so that the opening degree of the valve member 52 becomes the target value α. The ECU 12 may control the electric power supplied to the actuator 53 based on the value of the electrical signal output from the opening sensor 55, and set the opening of the valve member 52 to a predetermined target value α. Further, as shown in FIGS. 5 and 6, the opening degree of the EGR device 50 is time-shifted between a predetermined target value and a substantial value detected by the opening degree sensor 55.

  When the opening degree of the valve member 52 of the EGR device 50 is driven to the target value α in step S103, the ECU 12 turns on the energization stop flag at timing t4. Thereby, the energization to the actuator 53 is stopped. Further, as shown in FIG. 6, when it is detected that the valve member 52 of the EGR device 50 is not fully closed in step S102, that is, between timings t1 and t3, that is, when the valve member 52 is open, the ECU 12 similarly The energization stop flag is set to ON, and energization to the actuator 53 is stopped (S104). By stopping energization of the actuator 53, the force applied from the actuator 53 to the valve member 52 disappears. Therefore, if the spring 54 is normal, the pressing force of the spring 54 is applied to the valve member 52.

  When the ECU 12 stops energizing the actuator 53 in step S104, the opening degree of the valve member 52 is compared with a preset opening degree value β (S105). Specifically, the ECU 12 stops energization of the actuator 53 at the timing t4, and detects whether the opening degree of the valve member 52 is larger than the opening value β at the timing t5 when a predetermined period has elapsed. The ECU 12 detects the opening degree of the valve member 52 based on the electrical signal output from the opening degree sensor 55.

  If the spring 54 is normal, the pressing force of the spring 54 is applied to the valve member 52. Therefore, when energization to the actuator 53 is stopped, the valve member 52 rotates to a position where the EGR passage 56 which is the initial position is fully closed by the pressing force of the spring 54 by the timing t5. On the other hand, when an abnormality occurs in the spring 54, the pressing force from the spring 54 is not applied to the valve member 52. Therefore, even when the energization of the actuator 53 is stopped and the timing t5 when a predetermined period has elapsed, the opening degree of the valve member 52 becomes larger than the opening degree value β.

Therefore, after stopping energization of the actuator 53 in step S104, the ECU 12 applies the spring 54 to the spring 54 when the opening degree of the valve member 52 does not become smaller than the opening value β at the timing t5 when a predetermined period has elapsed. It is determined that an abnormality has occurred (S106). The abnormality of the spring 54 is, for example, the bending of the spring 54 or the fall of the spring 54. On the other hand, at the timing t5 when the predetermined period has elapsed, when the opening degree of the valve member 52 is smaller than the opening degree value β, the ECU 12 determines that the spring 54 is normal. Then, the ECU 12 ends the abnormality detection of the EGR device 50 and turns off the energization stop flag.
By the above-described procedure, abnormality detection of the EGR device 50, particularly abnormality detection of the spring 54 of the EGR device 50 is performed. When the accelerator opening again becomes greater than 0 at timing t6, the vehicle shifts to an acceleration state.

(fail safe)
When an abnormality of the EGR device 50 is detected by the above-described procedure, the ECU 12 performs fail-safe according to the flowchart shown in FIG.
The ECU 12 detects an abnormality of the EGR device 50 by the procedure shown in FIG. 7 (S201). When an abnormality is detected in the spring 54 of the EGR device 50, the warning unit 83 is activated (S202). As described above, the warning unit 83 audibly or visually warns the passenger of the occurrence of an abnormality. Thereby, the ECU 12 prompts the passenger to recognize the occurrence of the abnormality.

  The ECU 12 generates a warning and changes the energization program for the actuator 53 (S203). The energization program is a relationship between the opening degree of the valve member 52 and the power supplied to the actuator 53 as shown in FIG. The spring 54 presses the valve member 52 in a direction to close the EGR passage 56. Therefore, if the spring 54 is normal, the actuator 53 needs to drive the valve member 52 against the pressing force of the spring 54. As a result, in order to set the valve member 52 to a predetermined opening, it is necessary to supply relatively large power to the actuator 53. If the spring 54 is normal, the reaction force of the spring 54 increases as the opening of the valve member 52 increases. Therefore, the electric power supplied to the actuator 53 increases as the opening degree of the valve member 52 increases. On the other hand, if an abnormality occurs in the spring 54, no force is applied from the spring 54 to the valve member 52. Therefore, the valve member 52 is driven to a predetermined opening degree with a relatively small force. Further, when an abnormality occurs in the spring 54, the reaction force of the spring 54 is not applied, so that the electric power supplied to the actuator 53 is substantially constant regardless of the opening degree of the valve member 52. As a result, the electric power supplied to the actuator 53 in order to make the valve member 52 have a predetermined opening is relatively small, and is almost constant regardless of the opening of the valve member 52.

  Therefore, as shown in FIG. 7, by changing the energization program for the actuator 53 to one that does not consider the pressing force of the spring 54, the actuator 53 has the valve member 52 even when the spring 54 is abnormal. Electric power corresponding to a predetermined opening degree is supplied. Therefore, even when an abnormality occurs in the spring 54, the EGR device 50 can be performed with high accuracy, and the deterioration of the exhaust performance of the engine body 11 and the deterioration of the operability of the engine body 11 can be reduced. The power supply program does not directly change the power supplied to the actuator 53, but may change the gain of the power supplied when the actuator 53 is feedback-controlled according to the opening degree of the valve member 52.

  As described above, in the first embodiment, the abnormality of the spring 54 that presses the valve member 52 in the closing direction is detected by driving the valve member 52 during operation of the engine body 11. Further, the ECU 12 detects an abnormality of the spring 54 even when the engine body 11 is in operation, particularly when it is determined that the vehicle on which the engine body 11 is mounted is decelerating. Therefore, even if the EGR device 50 is operated during the operation of the engine main body 11 to detect an abnormality of the spring 54, the exhaust performance of the engine main body 11 and the deterioration of the operability of the engine main body 11 are reduced. Therefore, the abnormality of the spring 54 can be detected at an early stage without affecting the operating state.

  When an abnormality is detected, the ECU 12 activates the warning unit 83 and changes the energization program for the actuator 53. Thereby, even if abnormality has arisen in the spring 54, the operation | movement of the EGR apparatus 50 is ensured. Therefore, the deterioration of the exhaust performance of the engine main body 11 and the deterioration of the operability of the engine main body 11 can be reduced until the spring 54 is replaced.

(Second Embodiment)
An abnormality detection of the EGR device in the diesel engine system according to the second embodiment of the present invention will be described. The configuration of the diesel engine system is substantially the same as that of the first embodiment.
The ECU 12 energizes the actuator 53 and drives the valve member 52. Then, the power supplied to the actuator 53 and the opening degree of the valve member 52 are detected. The ECU 12 detects the opening degree of the valve member 52 based on an electric signal output from the opening degree sensor 55. At this time, the ECU 12 records the detected power and opening. Therefore, the ECU 12 has, as a map, a relationship between the power supplied to the actuator 53 and the opening degree of the valve member 52 corresponding to the power as shown in FIG.

Therefore, in the second embodiment, the abnormality of the spring 54 is detected along the flowchart shown in FIG.
When it is time to detect an abnormality, the ECU 12 detects whether the engine body 11 is in operation and the vehicle on which the engine body 11 is mounted is decelerating (S301). If the vehicle is not decelerating, the ECU 12 ends the abnormality detection.

  When the ECU 12 detects that the vehicle on which the engine body 11 is mounted is decelerating, the ECU 12 supplies electric power to the actuator 53 and detects the opening degree of the valve member 52. The ECU 12 supplies electric power to the actuator 53 and detects whether the opening degree of the valve member 52 is a predetermined value γ (S302). The ECU 12 detects the opening degree of the valve member 52 from the electric signal output from the opening degree sensor 55. The ECU 12 controls the electric power supplied to the actuator 53 so that the opening degree of the valve member 52 becomes a predetermined value γ.

  ECU12 detects the electric power supplied to the actuator 53, when the opening degree of the valve member 52 is the predetermined value (gamma). Then, the ECU 12 determines whether the power supplied to the actuator 53 is equal to or less than a preset set value δ (S303). The spring 54 presses the valve member 52 in a direction to close the EGR passage 56. Therefore, if the spring 54 is normal, the power supplied to the actuator 53 is large, and if the spring 54 is abnormal, the power supplied to the actuator 53 is small. As a result, when an abnormality has occurred in the spring 54, the electric power required to drive the opening of the valve member 52 to the predetermined value γ is reduced. Therefore, when the opening degree of the valve member 52 is the predetermined value γ, the ECU 12 determines that an abnormality has occurred in the spring 54 if the power supplied to the actuator 53 is equal to or less than the set value δ (S304). If an abnormality of the spring 54 is detected, fail-safe may be performed as in the first embodiment.

  The power supplied to the actuator 53 and the set value δ are not compared. Instead, the power supplied to the actuator 53 is recorded every time the abnormality detection procedure is performed, and the power recorded in the previous abnormality detection procedure is compared with this time. It is good also as a structure which compares with the electric power recorded by this abnormality detection procedure. The ECU 12 may determine that an abnormality has occurred in the spring 54 when there is a large difference between the power recorded in the previous abnormality detection procedure and the power recorded in the current abnormality detection procedure.

As described above, in the second embodiment, when the opening degree of the valve member 52 is made constant, the abnormality of the spring 54 is detected based on the amount of power supplied to the actuator 53. Therefore, the abnormality of the spring 54 can be detected quickly and accurately.
The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

The schematic diagram which shows the EGR apparatus by 1st Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the diesel engine system to which the EGR apparatus by 1st Embodiment of this invention is applied. The block diagram which shows the diesel engine system to which the EGR apparatus by 1st Embodiment of this invention is applied. Schematic which shows the flow of abnormality detection by the diesel engine system to which the EGR apparatus by 1st Embodiment of this invention is applied. Schematic which shows the timing chart of the abnormality detection by the diesel engine system to which the EGR apparatus by 1st Embodiment of this invention is applied. BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the diesel engine system to which the EGR apparatus by 1st Embodiment of this invention is applied. The schematic diagram which shows the relationship between the opening degree of an EGR apparatus, and the electric power supplied to an actuator. Schematic which shows the flow of the fail safe when abnormality is detected in the diesel engine system to which the EGR device by a 1st embodiment of the present invention is applied. Schematic which shows the flow of abnormality detection by the diesel engine system to which the EGR apparatus by 2nd Embodiment of this invention is applied.

Explanation of symbols

  11: Engine body (internal combustion engine), 12: ECU (control device, abnormality detection means, operating state detection means, power supply means), 20: intake system, 30: exhaust system, 50: EGR device, 52: valve member, 53: Actuator, 54: Spring (elastic member), 55: Opening sensor (opening detecting means), 56: EGR passage, 81: Revolution sensor (operating state detecting means), 82: Accelerator sensor (operating state detecting means) ), 83: Warning section (warning means)

Claims (6)

A valve member that opens and closes an exhaust gas recirculation passage through which exhaust gas recirculated from the exhaust system of the internal combustion engine to the intake system flows;
An actuator for electrically driving the valve member;
An elastic member that presses the valve member in a direction to close the exhaust gas recirculation passage;
Driving state detecting means for detecting the state of the vehicle equipped with the internal combustion engine;
An opening degree detecting means for detecting an opening degree of the valve member;
An abnormality detecting means for driving the valve member when the internal combustion engine is in operation and detecting an abnormality of the elastic member from the behavior of the valve member;
With
The abnormality detection means energizes the actuator when the driving state detection means detects that the vehicle is decelerating and the opening degree detection means detects that the valve member is fully closed. An exhaust gas recirculation apparatus , wherein after the valve member is driven to a preset opening, energization to the actuator is stopped to detect abnormality of the elastic member . The abnormality detecting means detects an abnormality of the elastic member when the opening degree of the valve member detected by the opening degree detecting means is equal to or greater than a predetermined value even after a predetermined period of time has elapsed after stopping energization of the actuator. exhaust gas recirculation system according to claim 1, wherein it is determined that. The abnormality detection means includes
When driving the valve member to a certain degree, exhaust gas recirculation system according to claim 1, wherein for detecting an abnormality of the elastic member from the power supplied to the actuator. The abnormality detection means includes
The exhaust gas recirculation apparatus according to claim 3 , wherein when the change in power supplied to the actuator is small regardless of the opening degree of the valve member detected by the opening degree detecting means, it is determined that the elastic member is abnormal. The exhaust gas recirculation apparatus according to claim 2 or 4 , further comprising power supply means for changing a relationship between an opening degree of the valve member and power supplied to the actuator when the elastic member is determined to be abnormal. 6. The exhaust gas recirculation apparatus according to claim 2 , further comprising warning means for warning a driver of the vehicle when the elastic member is determined to be abnormal.

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