JP6295725B2 - Turbocharger abnormality determination device - Google Patents

Description

  The present invention relates to an abnormality determination device for a turbocharger having a waste gate valve.

  In recent years, a turbine housing of a turbocharger has been provided with a bypass passage that communicates with a portion on the exhaust upstream side and a portion on the downstream side of the turbine wheel in a shape extending around the turbine wheel, and communication with the bypass passage. It is often used to provide a waste gate valve that switches between blocking the communication (see, for example, Patent Document 1).

  In the device described in Patent Document 1, a driving actuator is connected to a waste gate valve via a link mechanism. The waste gate valve is driven to open and close through the actuator operation control.

  Further, in the apparatus described in Patent Document 1, when the waste gate valve is closed, a process (initialization process) is performed in which the operating position when the valve body hits the valve seat portion is the fully closed position of the waste gate valve. Executed. By performing such initialization processing, the actuator is driven to a position where the valve body is seated on the bubble seat portion when the waste gate valve is closed.

JP 2012-67698 A

  By the way, since the turbine housing becomes high temperature by receiving heat from the high temperature exhaust, the valve seat portion provided in the turbine housing also becomes high temperature. If the valve seat is repeatedly seated on the valve seat while the valve seat is hot, or if the valve is pressed strongly against the valve seat, the vicinity of the valve seat is plastically deformed and waste The fully closed position of the gate valve may change.

  Even in such a case, in the apparatus described in Patent Document 1, since the above-described initialization process is executed, the valve body is seated on the bubble seat portion when the waste gate valve is closed. However, when the amount of plastic deformation in the vicinity of the valve seat portion increases, the internal stress of the turbine housing increases, leading to a decrease in rigidity. This may cause cracks in the turbine housing in some cases.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an abnormality determination device for a turbocharger that can determine that a crack is likely to occur.

  An abnormality determination device for a turbocharger for achieving the above-described object includes a bypass passage that communicates a portion on the exhaust upstream side and a portion on the downstream side of the turbine wheel, and communication by the bypass passage and blocking of the communication. A turbine housing having a wastegate valve for switching between. The abnormality determination apparatus includes an actuator that opens and closes the waste gate valve, a control unit that performs operation control of the actuator, and a detection unit that detects a fully closed position of the waste gate valve. Then, when the temperature of the turbocharger is equal to or lower than the determination temperature by the determination unit and the deviation amount between the predetermined reference position and the fully closed position detected by the detection unit is larger than the determination value, It is determined that the turbocharger is abnormal.

  As described above, if the amount of plastic deformation in the vicinity of the valve seat portion of the waste gate valve in the turbine housing increases, the possibility of cracks in the turbine housing increases. Further, when the amount of plastic deformation increases, the amount of deviation of the actual fully closed position of the waste gate valve from a predetermined reference position (for example, a position when the amount of plastic deformation is “0”) also increases. For this reason, it is possible to accurately determine that the turbine housing may be cracked due to the large amount of deviation between the actual fully closed position and the reference position. In this regard, in the abnormality determination device, it is determined that there is an abnormality in the turbocharger when the deviation amount between the predetermined reference position and the fully closed position detected by the detection unit is larger than the determination value. Therefore, it is possible to accurately determine that there is a possibility that the turbocharger is abnormal, specifically, the crack is generated in the turbine housing.

  Further, the temperature of the turbocharger changes according to its operating state. When the temperature of the turbocharger changes, the amount of thermal expansion of each part (for example, the turbine housing, wastegate valve, and actuator) changes individually, and along with this, the wastegate valve detected by the detection part is fully closed. The position will also change. For this reason, if the abnormality of the turbocharger is determined simply based on the fully closed position detected by the detection unit, the determination accuracy may be lowered due to the influence of thermal expansion of each part of the turbocharger. In this regard, in the abnormality determination device, it is determined that the turbocharger is abnormal when the deviation amount is larger than the determination value in a situation where the temperature of the turbocharger is equal to or lower than the determination temperature. Therefore, when the temperature of the turbocharger is low and the amount of thermal expansion of each part is small, that is, when it is difficult to be affected by the thermal expansion of each part of the turbocharger, the abnormality determination is executed based on the fully closed position detected by the detection unit. It is possible to accurately determine that there is a possibility of occurrence of cracks in the turbine housing.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows schematic structure of the abnormality determination apparatus of the turbocharger of one Embodiment. The perspective view which shows the perspective structure of the turbine housing of the turbocharger. Sectional drawing which shows the cross-sectional structure along line 3-3 of FIG. 2 of a turbine housing. The flowchart which shows the execution procedure of a determination process.

Hereinafter, an embodiment of a turbocharger abnormality determination device will be described.
As shown in FIG. 1, the turbocharger 20 includes a compressor 21 provided in the intake passage 11 of the internal combustion engine 10 and a turbine 22 provided in the exhaust passage 12. The compressor 21 includes a compressor impeller 23 inside, and the turbine 22 includes a turbine wheel 24 inside. The compressor impeller 23 and the turbine wheel 24 are connected via a shaft 25 so as to be integrally rotatable. In such a turbocharger 20, when the exhaust of the internal combustion engine 10 is blown onto the turbine wheel 24, the turbine wheel 24 and the compressor impeller 23 rotate together, whereby the intake air flowing through the intake passage 11 is pressurized and the internal combustion engine 10. It is forced into the combustion chamber.

  The turbine 22 is provided with a bypass passage 26 having a shape extending around the turbine wheel 24. The bypass passage 26 extends in a shape that communicates a portion on the exhaust upstream side and the portion on the downstream side of the turbine wheel 24 in the exhaust passage 12. The turbine 22 is provided with a waste gate valve 27 for switching between communication by the bypass passage 26 and blocking of the communication.

  As shown in FIG. 2 or 3, a water jacket 31 in which cooling water circulates is formed inside the turbine housing 30. The turbine housing 30 is formed with an inlet 31 </ b> A for introducing cooling water into the water jacket 31 and an outlet 31 </ b> B for discharging cooling water from the inside of the water jacket 31 to the outside. A part of the cooling water of the internal combustion engine 10 is supplied to the water jacket 31 and circulates through the inlet 31A and the outlet 31B.

  The turbine housing 30 is substantially entirely formed of an aluminum alloy. The turbine housing 30 is formed with the bypass passage 26. As shown in FIG. 3, the bypass passage 26 includes a communication passage 32 and a through hole 33. The communication passage 32 is formed in a shape communicating with a portion of the exhaust passage 12 (see FIG. 1) on the exhaust downstream side of the turbine wheel 24, and the through hole 33 is formed on the exhaust passage 12 with a portion of the exhaust upstream side of the turbine wheel 24. A shape communicating with the communication path 32 is formed.

  As shown in FIG. 2 or 3, the waste gate valve 27 has a valve seat 41 at the periphery of the opening on the side of the communication path 32 in the through hole 33. The waste gate valve 27 includes a valve body 46 connected to an electric actuator 44 through a link mechanism 42. The link mechanism 42 includes a swing arm 43 that swings about the axis of the rotary shaft 36 as a swing center. A drive rod 45 of the actuator 44 is connected to one end of the swing arm 43 so as to be relatively rotatable, and a disc-shaped valve body 46 is connected to the other end of the swing arm 43. It is attached integrally by 46A.

  The internal combustion engine 10 and the turbocharger 20 are provided with various sensors as peripheral devices. As these sensors, for example, the position sensor 51 for detecting the operating position of the waste gate valve 27 (specifically, the operating position of the actuator 44) or the ON operation when starting the operation of the internal combustion engine 10, An operation switch 52 that is turned off when the operation of the internal combustion engine 10 is stopped is provided.

  Further, as a peripheral device, an electronic control device 50 composed of a microcomputer or the like is provided. The electronic control device 50 takes in the output signals of various sensors and performs various calculations based on the signals, and performs various controls related to the operation of the internal combustion engine 10 such as operation control of the actuator 44 based on the calculation results. Run.

  In addition, a relay 53 is provided as the peripheral device. The relay 53 continues to supply power to the actuator 44, the position sensor 51, and the electronic control unit 50 for a period until the determination process described later is completed after the operation of the internal combustion engine 10 is stopped by turning off the operation switch 52. .

  In the operation control of the actuator 44, the operation position of the swing arm 43 is changed according to the operating state of the internal combustion engine 10, as indicated by the black arrow in FIG. Through the operation control of the actuator 44, when the valve body 46 reaches the position where the valve seat 46 is seated on the valve seat portion 41 (position shown in FIG. 3 [fully closed position]), the through-hole 33 is closed, and the bypass passage 26 is also closed. (The closed state). On the other hand, when the valve body 46 is separated from the valve seat portion 41 (valve open position), the through hole 33 is opened, so that the bypass passage 26 is opened (valve open state).

In the present embodiment, when the waste gate valve 27 is closed, a learning process for learning the fully closed position of the waste gate valve 27 is executed.
In this learning process, first, operation control (butting control) of the actuator 44 is performed so that the valve body 46 of the waste gate valve 27 is butted against the valve seat portion 41. When the current consumption of the actuator 44 becomes a predetermined value or more during execution of the abutting control, it is assumed that the valve body 46 has abutted against the valve seat portion 41, and the operating position of the waste gate valve 27 at this time is the position. The operation position is detected by the sensor 51 and stored as a fully closed position. Thereafter, the operation control of the actuator 44 is executed based on the stored fully closed position.

  Note that, when the valve body 46 hits the valve seat portion 41 when the waste gate valve 27 is driven to close, the load applied to the actuator 44 increases rapidly, so that the current consumption of the actuator 44 increases rapidly. The current consumption amount at this time is larger than the maximum value of the current consumption amount of the actuator 44 when the valve body 46 of the waste gate valve 27 does not abut against the valve seat portion 41. In the present embodiment, an amount slightly larger than the maximum value is set as the predetermined value. Therefore, it is possible to accurately determine that the valve body 46 has come into contact with the valve seat portion 41 when the consumption current amount of the actuator 44 is equal to or greater than a predetermined value.

  By the way, since the turbine housing 30 becomes high temperature by receiving heat from the high-temperature exhaust, the valve seat portion 41 provided in the turbine housing 30 also becomes high temperature. If the valve body 46 is repeatedly seated on the valve seat 41 while the valve seat 41 is at a high temperature, or if the valve body 46 is strongly pressed against the valve seat 41, the vicinity of the valve seat 41 will be depressed. May deform plastically. If the amount of plastic deformation increases, the internal stress of the turbine housing 30 increases, leading to a decrease in rigidity and possibly cracking in the turbine housing 30. As a result, there is a risk of exhaust gas leakage from the turbocharger 20 or overheating of the turbocharger 20 due to cooling water leakage from the water jacket 31.

In the present embodiment, in order to appropriately deal with such an abnormality of the turbocharger 20, a process for determining the abnormality (determination process) is executed.
In this determination process, a deviation amount ΔP between the fully closed position of the waste gate valve 27 detected by the position sensor 51 and a predetermined reference position (specifically, a fully closed position in a turbocharger having a standard characteristic). Is calculated. When the deviation amount ΔP is larger than the determination value J, it is determined that the turbocharger 20 is abnormal. Hereinafter, an operation by executing the determination process will be described.

  As described above, when the amount of plastic deformation of the turbine housing 30 increases, the possibility of cracks occurring in the turbine housing 30 increases. Further, when the amount of plastic deformation in the vicinity of the valve seat portion 41 of the turbine housing 30 increases, the amount of deviation of the actual fully closed position of the waste gate valve 27 from the reference position also increases, and thus the amount of deviation increases. Thus, it can be accurately determined that the turbine housing 30 may be cracked.

  In the determination process of the present embodiment, when the deviation amount ΔP between the reference position and the fully closed position detected by the position sensor 51 is larger than the determination value J, it is determined that there is an abnormality in the turbocharger 20. Therefore, it is possible to accurately determine that there is an abnormality in the turbocharger 20, specifically, that there is a possibility of occurrence of a crack in the turbine housing 30. Note that, as the determination value J, a value that can appropriately determine that the deviation amount ΔP is large enough to cause a crack in the turbine housing 30 is the result of experiments and simulations. And stored in the electronic control unit 50 in advance.

  Here, the temperature of the turbocharger 20 changes according to its operating state. When the temperature of the turbocharger 20 changes, the amount of thermal expansion of each part (for example, the turbine housing 30, the waste gate valve 27, the link mechanism 42, and the actuator 44) changes individually. Accordingly, the relative position of each part of the turbocharger 20 changes, so that the fully closed position of the waste gate valve 27 detected by the position sensor 51 also changes. Therefore, even if the abnormality of the turbocharger 20 is determined simply based on the fully closed position detected by the position sensor 51, the determination accuracy is lowered due to the influence of thermal expansion of each part of the turbocharger 20.

  Based on this point, in the determination process of the present embodiment, the actual fully closed position is detected by the position sensor 51 when the elapsed time after the operation of the internal combustion engine 10 is stopped for a predetermined time or more. This is executed when a predetermined time has elapsed since the operation switch 52 was turned off. In the present embodiment, the elapsed time after the operation of the internal combustion engine 10 is stopped, and the temperature of the turbocharger 20 is reliably determined by the temperature drop after the operation is stopped (so that high determination accuracy can be obtained in the determination process). The time when the temperature becomes less than or equal to the temperature is determined in advance based on the results of various experiments and simulations. The same time is stored in the electronic control unit 50 as the predetermined time.

  In the determination process, when the deviation amount ΔP between the fully closed position detected by the position sensor 51 and the reference position is larger than the determination value J, it is determined that the turbocharger 20 is abnormal. Therefore, the determination of the abnormality is performed based on the fully closed position detected when the temperature of the turbocharger 20 is low and the thermal expansion amount of each part is small, that is, when it is not easily affected by the thermal expansion of each part of the turbocharger 20. It is possible to accurately determine that there is a possibility of occurrence of cracks in the turbine housing 30.

Hereinafter, the execution procedure of the determination process will be described with reference to FIG.
Note that the series of processes shown in the flowchart of FIG. 4 conceptually shows the execution procedure of the determination process, and the actual process is executed by the electronic control unit 50 as an interrupt process at predetermined intervals. The

In this process, first, it is determined whether or not the operation switch 52 is turned off and a predetermined time has elapsed after the operation switch 52 is turned off (step S11).
Then, when the operation switch 52 is turned off and a predetermined time elapses thereafter (step S11: YES), processing for detecting the fully closed position of the waste gate valve 27 is executed (steps S12 to S14). Here, the same processing as the learning processing is executed. That is, first, operation control of the actuator 44 (the abutting control) is performed so that the valve body 46 of the waste gate valve 27 abuts against the valve seat portion 41 (step S12). When it is determined that the current consumption of the actuator 44 is equal to or greater than the predetermined value and the fully closed position is reached (step S13: YES), the position sensor 51 detects the operating position of the waste gate valve 27 at that time. At the same time, the operating position is stored as a fully closed position (step S14).

  Thereafter, a difference (= Pr−Pi) between the fully closed position Pr newly stored in the process of step S14 and the fully closed position Pi stored when the process of step S14 is executed is calculated. Is stored as the deviation amount ΔP (step S15). In the present embodiment, the movement position of the waste gate valve 27 detected by the position sensor 51 becomes larger as the position is farther from the most open position (fully opened position).

  Then, it is determined whether or not the deviation amount ΔP is larger than the determination value J (step S16). When the deviation amount ΔP is larger than the determination value J (step S16: YES), it is determined that there is an abnormality in the turbocharger 20 (step S17). In the present embodiment, in this case, a warning lamp is turned on during the subsequent operation of the internal combustion engine 10 to notify the driver of the abnormality of the turbocharger 20. On the other hand, when the deviation amount ΔP is equal to or smaller than the determination value J (step S16: NO), it is determined that the turbocharger 20 has no abnormality (step S18).

  As described above, after the presence / absence of abnormality of the turbocharger 20 is determined based on the deviation amount ΔP, the present process is terminated. Thereafter, the relay 53 is turned off, and the power supply to each part of the system is interrupted.

As described above, according to the present embodiment, the following effects can be obtained.
(1) When the position sensor 51 detects the fully closed position of the waste gate valve 27 when the temperature of the turbocharger 20 is equal to or lower than a predetermined temperature, and the deviation ΔP between the fully closed position and the reference position is greater than the determination value J In addition, the turbocharger 20 is determined to have an abnormality. Therefore, it is possible to accurately determine that there is a high possibility that a crack will occur in the turbine housing 30 based on the shift amount ΔP that increases when the plastic deformation amount of the turbine housing 30 increases. . Further, the abnormality determination is performed based on the fully closed position detected when the temperature of the turbocharger 20 is low and the thermal expansion amount of each part is small, that is, when the turbocharger 20 is hardly affected by the thermal expansion of each part. Therefore, it is possible to accurately determine that the turbine housing 30 may be cracked.

The above embodiment may be modified as follows.
-The process of step S18 of the determination process (FIG. 4) may be omitted. Specifically, when the deviation amount ΔP is equal to or smaller than the determination value J (step S16: NO), the turbocharger 20 is not determined to be abnormal (jumping the processing of step S17), and the turbocharger is also determined. This process may be terminated without determining that there is no abnormality in 20.

  The process for calculating the deviation amount between the fully closed position of the waste gate valve 27 detected by the position sensor 51 and a predetermined reference position can be arbitrarily changed. This deviation amount can be calculated as follows, for example. That is, first, a predetermined position (specifically, a fully closed position in a turbocharger with standard characteristics) is determined in advance as a reference position. And the deviation | shift amount of the fully closed position memorize | stored by the process of step S14 of a determination process and the said predetermined position is calculated.

  ・ When it is determined that the turbocharger 20 is abnormal in the determination process, the warning light is not lit, but a buzzer is heard during the subsequent operation of the internal combustion engine 10 and an indication that there is an abnormality in the navigation system is displayed. You may do it. In short, it is only necessary to notify the driver of the abnormality of the turbocharger 20. In addition, when it is determined that there is an abnormality in the turbocharger 20 in the determination process, output restriction may be executed when the internal combustion engine 10 is operated thereafter.

  In the above embodiment, it is determined that the temperature of the turbocharger 20 is equal to or lower than the predetermined temperature based on the elapsed time after the operation of the internal combustion engine 10 is stopped for a predetermined time or longer. Instead of this, a temperature sensor that detects the temperature of the turbocharger 20 may be newly provided, and it may be determined that the temperature of the turbocharger 20 is equal to or lower than a predetermined temperature based on the temperature detected by the temperature sensor. .

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Intake passage, 12 ... Exhaust passage, 20 ... Turbocharger, 21 ... Compressor, 22 ... Turbine, 23 ... Compressor impeller, 24 ... Turbine wheel, 25 ... Shaft, 26 ... Bypass passage, 27 ... Waste 30 ... Turbine housing, 31 ... Water jacket, 31A ... Inlet port, 31B ... Discharge port, 32 ... Communication path, 33 ... Through hole, 36 ... Rotating shaft, 41 ... Valve seat part, 42 ... Link mechanism, 43 DESCRIPTION OF SYMBOLS ... Swing arm, 44 ... Actuator, 45 ... Drive rod, 46 ... Valve body, 46A ... Connection pin, 50 ... Electronic control unit (control part and determination part), 51 ... Position sensor (detection part), 52 ... Operation switch 53. Relay.

Claims (1)

A bypass passage that communicates a portion on the exhaust upstream side and a portion on the downstream side of the turbine wheel, and a turbine housing having a wastegate valve that switches between communication by the bypass passage and blocking of the communication;
An actuator for opening and closing the waste gate valve;
A control unit that performs operation control of the actuator;
A detection unit for detecting a fully closed position of the waste gate valve;
When the temperature of the turbocharger is equal to or lower than the determination temperature and the deviation amount between the predetermined reference position and the fully closed position detected by the detection unit is larger than the determination value, it is determined that the turbocharger is abnormal. An abnormality determination device for a turbocharger, comprising: a determination unit that performs the operation.