JP2011247181A - Failure detecting device of internal combustion engine with supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect that a diffuser vane has a failure, and to specify a type thereof.SOLUTION: A failure detecting device of an internal combustion engine with a supercharger, wherein the internal combustion engine includes the supercharger and the supercharger has a variable diffuser for changing an angle of the diffuser vane in a compressor part, includes a determiner for determining a failure state of the diffuser vane on the basis of a compressor efficiency when an intake air amount of the internal combustion engine is smaller than a first predetermined value and a compressor efficiency when the intake air amount of the internal combustion engine is larger than a second predetermined value which is larger than the first predetermined value.

Description

  The present invention relates to a failure detection apparatus for an internal combustion engine including a supercharger.

  In the internal combustion engine, if a turbocharger that is driven by using the energy of the exhaust gas discharged from the internal combustion engine is provided, the charging efficiency of the combustion chamber can be increased and the engine output can be further increased.

  And the turbocharger which has a variable diffuser can change a supercharging pressure by changing the opening (henceforth VGD opening) of a diffuser vane. Here, a technique for controlling the opening degree of the diffuser vane based on the engine speed and the pressure (supercharging pressure) at the compressor outlet is known (for example, see Patent Document 1).

  By the way, the actual VGD opening (hereinafter also referred to as the actual VGD opening) is deviated from the target VGD opening (hereinafter also referred to as the target VGD opening), or a part of the diffuser vane is damaged or dropped out. When an abnormality occurs, the compressor efficiency changes. Here, when an abnormality occurs in which the actual VGD opening deviates from the target VGD opening, the abnormality can be solved by returning the diffuser vane to the reference position and learning (memory) the position. . However, when an abnormality occurs in which a part of the diffuser vane is broken or dropped, it is necessary to control the output of the internal combustion engine and warn the driver of this abnormality. As described above, since the countermeasures are different between the abnormality in which the opening degree of the diffuser vane deviates from the target and the abnormality in which the diffuser vane is lost, it is necessary to determine what abnormality has occurred.

JP 2007-132232 A

  The present invention has been made in view of the above-described problems, and an object of the present invention is to detect that an abnormality has occurred in the diffuser vane and to identify the type of the abnormality.

In order to achieve the above object, a failure detection apparatus for an internal combustion engine equipped with a supercharger according to the present invention comprises:
In a failure detection device for an internal combustion engine provided with a supercharger having a variable diffuser for changing the angle of a diffuser vane in a compressor part,
Compressor efficiency when the intake air amount of the internal combustion engine is smaller than a first predetermined value, and compressor efficiency when the intake air amount of the internal combustion engine is larger than a second predetermined value larger than the first predetermined value; And determining means for determining an abnormal state of the diffuser vane based on the above.

The first predetermined value is an intake air amount such that the opening degree of the diffuser vane is closer to the closing side than 50%. The first predetermined value may be an intake air amount on the side where the opening is smaller than the center of the range in which the opening of the diffuser vane changes. This can be when the amount of intake air is relatively small or when the opening of the diffuser vane is relatively small. Further, the second predetermined value is an intake air amount such that the opening degree of the diffuser vane is on the opening side with respect to 50%. The second predetermined value may be the intake air amount on the side where the opening is larger than the center of the range in which the opening of the diffuser vane changes. This can be when the amount of intake air is relatively large or when the opening of the diffuser vane is relatively large. Note that the first predetermined value and the second predetermined value may be the same value. Then, the compressor efficiency is obtained when the intake air amount is large and when the intake air amount is small, and abnormality of the diffuser vane is determined based on the compressor efficiency. That is, because the difference in the compressor efficiency between when the intake air amount is large and when the amount of intake air is small, the difference in the opening degree of the diffuser vane and the loss of the diffuser vane are different. Can be determined.

  In the present invention, the determination means has a compressor efficiency greater than a normal range of the compressor efficiency when the intake air amount of the internal combustion engine is smaller than the first predetermined value, and the intake air amount of the internal combustion engine is When the compressor efficiency when the compressor efficiency is greater than the second predetermined value is smaller than the normal range of the compressor efficiency, it is determined that the actual opening degree of the diffuser vane is deviated from the target opening degree toward the closing side. Can do.

  Here, when the diffuser vane is normal, the compressor efficiency when the intake air amount of the internal combustion engine is smaller than the first predetermined value and the compressor efficiency when the intake air amount of the internal combustion engine is larger than the second predetermined value are obtained. Each falls within the normal range. The normal range of the compressor efficiency is a range that the compressor efficiency can take when there is no abnormality in the diffuser vane, and may be obtained by experiments or the like. Note that the normal range differs for each intake air amount, and may have a certain range in consideration of the influence of errors and the like.

  However, if the actual opening degree of the diffuser vane is shifted to the closing side from the target opening degree, the intake air amount is limited as compared with the normal time. Here, when the intake air amount is low, the diffuser vane opening is relatively small. At this time, the actual opening of the diffuser vane is shifted to the closing side from the target opening. And compressor efficiency becomes higher than normal. That is, when the amount of intake air is small, the compressor efficiency is increased by reducing the opening degree of the diffuser vane. Therefore, the compressor efficiency is further increased by shifting the opening degree of the diffuser vane toward the closing side.

  On the other hand, when the intake air amount is in an operating state, the opening degree of the diffuser vane is relatively large. At this time, if the actual opening degree of the diffuser vane is shifted to the closing side from the target opening degree, The compressor efficiency is lower than normal. That is, when the amount of intake air is large, the compressor efficiency is increased by increasing the opening degree of the diffuser vane. Therefore, when the opening degree of the diffuser vane is reduced due to the deviation, the compressor efficiency is lowered.

  To summarize these relationships, the compressor efficiency when the intake air amount of the internal combustion engine is smaller than the first predetermined value is larger than the normal range of the compressor efficiency, and the intake air amount of the internal combustion engine is smaller than the second predetermined value. When the compressor efficiency when it is large is smaller than the normal range of the compressor efficiency, it can be determined that the actual opening degree of the diffuser vane is shifted to the closing side from the target opening degree.

  In the present invention, it is provided with learning means for learning the position of the diffuser vane when it is determined by the determining means that the actual opening of the diffuser vane is shifted to the closing side from the target opening. be able to.

For example, when calculating the current opening by adding the amount of change in the opening of the diffuser vane, the error accumulates, so the difference between the calculated opening and the actual opening gradually increases. To go. On the other hand, if the diffuser vane is, for example, fully open or fully closed, thereafter, the amount of change in opening from the fully open or fully closed may be integrated. That is, after storing the position of the diffuser vane as fully open or fully closed, for example, the opening degree can be calculated without being affected by the error accumulated so far. An abnormality that shifts closer to the closing side than the target opening degree can be resolved.

  In the present invention, the determination means is configured such that the compressor efficiency when the intake air amount of the internal combustion engine is smaller than the first predetermined value is smaller than the normal range of the compressor efficiency, and the intake air amount of the internal combustion engine is When the compressor efficiency when larger than the second predetermined value is larger than the normal range of the compressor efficiency, the actual opening degree of the diffuser vane is shifted to the opening side from the target opening degree or the diffuser vane Can be determined to be missing.

  Loss of the diffuser vane includes a portion of the diffuser vane falling off or breaking. If the diffuser vane is missing, the vane spacing is increased and the intake resistance is reduced, so the compressor efficiency is the same as when the actual opening of the diffuser vane deviates from the target opening. Changes.

  When the actual opening degree of the diffuser vane is shifted to the opening side from the target opening degree or when the diffuser vane is lost, the resistance of the intake air becomes smaller than that in the normal state. Here, when the intake air amount is low, the diffuser vane opening is relatively small. At this time, the actual opening of the diffuser vane is shifted to the opening side from the target opening. Compressor efficiency is lower than normal. That is, when the amount of intake air is small, the compressor efficiency is increased by reducing the opening of the diffuser vane. Therefore, the compressor efficiency is further lowered by shifting the opening of the diffuser vane to the open side. The same is true if the diffuser vane is missing.

  On the other hand, when the intake air amount is in an operating state, the opening degree of the diffuser vane is relatively large. At this time, if the actual opening degree of the diffuser vane is shifted to the opening side from the target opening degree, The compressor efficiency will be higher than normal. That is, when the amount of intake air is large, the compressor efficiency is increased by increasing the opening degree of the diffuser vane. Therefore, if the opening degree of the diffuser vane is increased due to the deviation, the compressor efficiency is increased. The same is true if the diffuser vane is missing.

  To summarize these relationships, the compressor efficiency when the intake air amount of the internal combustion engine is smaller than the first predetermined value is smaller than the normal range of the compressor efficiency, and the intake air amount of the internal combustion engine is smaller than the second predetermined value. When the compressor efficiency when it is large is larger than the normal range of the compressor efficiency, it can be determined that the actual opening of the diffuser vane is shifted to the open side from the target opening or the diffuser vane is missing. .

In the present invention, the position of the diffuser vane is determined when it is determined by the determination means that the actual opening of the diffuser vane is shifted to the open side from the target opening or the diffuser vane is missing. With learning means to learn
The determination means has a compressor efficiency when the intake air amount of the internal combustion engine is smaller than the first predetermined value even after learning the position of the diffuser vane by the learning means. If the compressor efficiency when the intake air amount of the internal combustion engine is smaller and larger than the second predetermined value is larger than the normal range of the compressor efficiency, it can be determined that the diffuser vane is missing.

When the actual opening degree of the diffuser vane is shifted to the opening side from the target opening degree or when the diffuser vane is lost, since the resistance of the intake air is reduced, the compressor efficiency changes in the same way. Here, if the actual opening of the diffuser vane is shifted to the open side from the target opening, the learning vane learns the position of the diffuser vane and then the opening of the diffuser vane is targeted. Can be matched. Therefore, if the compressor efficiency is within the normal range after learning by the learning means, it can be determined that the actual opening of the diffuser vane has shifted to the opening side from the target opening before that time. On the other hand, if the compressor efficiency does not fall within the normal range after learning by the learning means, it can be determined that the diffuser vane has been lost. When the diffuser vane is lost, for example, by shifting to the fail-safe mode and suppressing the output of the internal combustion engine, it is possible to suppress the subsequent dropout and breakage of the diffuser vane.

  According to the present invention, it is possible to detect that an abnormality has occurred in the diffuser vane and to specify the type of the abnormality.

It is a figure which shows schematic structure of the internal combustion engine which concerns on an Example, and its intake / exhaust system. It is a figure which shows the operating state of a diffuser vane. It is a figure for demonstrating the structure of a variable diffuser. It is the figure which showed the relationship between the amount of intake air when a VGD opening degree is a close side rather than 50%, and a pressure ratio. It is the figure which showed the relationship between the amount of intake air when a VGD opening degree is an opening side rather than 50%, and a pressure ratio. The relationship between the intake air amount and the compressor efficiency when the VGD opening is a predetermined opening closer to the closing side than 50% when the actual VGD opening is closer to the closing side than the target VGD opening is shown. It is a figure. The relationship between the intake air amount and the compressor efficiency when the VGD opening is a predetermined opening on the opening side of the VGD opening when the actual VGD opening is closer to the closing side than the target VGD opening is shown. It is a figure. It is the figure which showed the relationship between the closed side compressor efficiency difference and the open side compressor efficiency difference in case the abnormality which the actual VGD opening degree becomes a close side rather than the target VGD opening degree has arisen. The relationship between the intake air amount and the compressor efficiency when the VGD opening is a predetermined opening closer to the closing side than 50% when the actual VGD opening is more open than the target VGD opening is shown. It is a figure. The relationship between the intake air amount and the compressor efficiency when the VGD opening is a predetermined opening on the opening side of more than 50% when the actual VGD opening is on the opening side of the target VGD opening has occurred. It is a figure. It is the figure which showed the relationship between the close side compressor efficiency difference and the open side compressor efficiency difference in case the abnormality in which the actual VGD opening is on the opening side than the target VGD opening occurs. It is the figure which showed the relationship between the amount of intake air and compressor efficiency when the VGD opening degree in the case where other abnormality has arisen is the predetermined opening degree of a close side rather than 50%. It is the figure which showed the relationship between the amount of intake air and compressor efficiency when the VGD opening degree in case other abnormality has arisen is the predetermined opening degree of the opening side rather than 50%. It is the figure which showed the relationship between the closed side compressor efficiency difference in case other abnormality has arisen, and the open side compressor efficiency difference. It is the flowchart which showed the flow of the failure detection which concerns on an Example.

  Hereinafter, specific embodiments of a failure detection apparatus for an internal combustion engine including a supercharger according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine 1 and its intake / exhaust system according to this embodiment. An internal combustion engine 1 shown in FIG. 1 is a water-cooled four-cycle diesel engine having four cylinders 2.

  An intake passage 3 and an exhaust passage 4 are connected to the internal combustion engine 1. The intake passage 3 is connected to the cylinder 2 via an intake port 2A, and the exhaust passage 4 is connected to the cylinder 2 via an exhaust port 2B.

  Further, the internal combustion engine 1 according to this embodiment includes a turbocharger 50 with a variable diffuser (hereinafter simply referred to as “turbocharger 50”). The turbocharger 50 includes a compressor housing 51, a turbine housing 52, and a center housing 53. The compressor housing 51 is provided in the middle of the intake passage 3, and the inside of the compressor housing 51 constitutes a part of the intake passage 3. The turbine housing 52 is provided in the middle of the exhaust passage 4, and the interior of the turbine housing 52 constitutes a part of the exhaust passage 4. The compressor housing 51 and the turbine housing 52 are connected via a center housing 53.

  A compressor impeller 54 having a plurality of blades is provided in the compressor housing 51, and a turbine impeller 55 having a plurality of blades is provided in the turbine housing 52. The compressor impeller 54 and the turbine impeller 55 are connected via a rotor shaft 56. An actuator 57 for rotating a later-described diffuser vane 61 is connected to the compressor housing 51 via a link rod 58.

  FIG. 2 is a view showing an operating state of the diffuser vane 61. In FIG. 2, a solid line indicates a state where the diffuser vane 61 is fully closed, and a broken line indicates a state where the diffuser vane 61 is fully open. FIG. 3 is a diagram for explaining the configuration of the variable diffuser 60.

  A variable diffuser 60 is disposed downstream of the compressor impeller 54 in the air passage in the compressor housing 51.

  A plurality of diffuser vanes 61 of the variable diffuser 60 are arranged on the outer periphery of the compressor impeller 54. Each diffuser vane 61 is rotatably attached to a donut board-like base plate 62 fixed to the compressor housing 51 via a rotation shaft 63. The rotating shaft 63 is disposed concentrically with the compressor impeller 54 at equal angular intervals.

  The variable diffuser 60 has a configuration for changing the openings of the plurality of diffuser vanes 61 all at once. The base plate 62 is provided with a unison ring 64 having a plurality of semicircular cutouts 64a on the inner peripheral side. In addition, one end of a driven arm 65 is fixed to the rotation shaft 63 of the diffuser vane 61.

  The other end of the driven arm 65 is formed in a circular shape and is engaged with the notch 64 a of the unison ring 64. The inner periphery of the unison ring 64 is guided by a plurality of guide rollers 66 attached to the base plate 62 so that the unison ring 64 can be rotated while being concentric with the base plate 62.

One end of a link rod 58 is rotatably attached to a protrusion 64b provided on the unison ring 64. The other end of the link rod 58 is connected to the actuator 57.

  According to the above configuration, when the ECU 10 gives a drive command to the actuator 57, the link rod 58 is driven in the arrow direction shown in FIG. Due to the movement of the link rod 58, the unison ring 64 is rotated in the direction of the arrow in FIG. Then, the rotational movement of the unison ring 64 is transmitted through the driven arm 65, whereby the openings of all the diffuser vanes 61 are changed at the same time. As described above, based on the drive command of the ECU 10, the opening degree of the diffuser vane 61 can be adjusted to an arbitrary opening degree between the solid line and the broken line in FIG.

  The base plate 62 is provided with a stopper 70 for restricting the rotation of the unison ring 64. The stopper 70 is installed so that the diffuser vane 61 is in a fully closed position in a state where the projection 64b provided on the unison ring 64 is in contact with the stopper 70.

  The internal combustion engine 1 configured as described above is provided with an ECU 10 that is an electronic control unit for controlling the internal combustion engine 1. The ECU 10 is a unit that controls the internal combustion engine 1 in accordance with the operating conditions of the internal combustion engine 1 and the driver's request.

  An actuator 57 is connected to the ECU 10 via an electric wiring, and the actuator 57 can be controlled by the ECU 10.

  Further, an inlet side pressure sensor 11 for measuring the pressure of intake air and an inlet side temperature sensor 12 for measuring the temperature of intake air are attached to the intake passage 3 upstream of the compressor housing 51. Further, in the intake passage 3 downstream of the compressor housing 51, an outlet side pressure sensor 13 that measures the pressure of the intake air, an outlet side temperature sensor 14 that measures the temperature of the intake air, and an air flow meter 15 that measures the flow rate of the intake air. Is attached. These sensors are connected to the ECU 10 via electric wiring, and output signals from these sensors are input to the ECU 10.

  In addition to the above sensors, a crank position sensor 16 that detects the engine speed is connected to the ECU 10 via electric wiring, and output signals of these various sensors are input to the ECU 10.

  The ECU 10 learns (stores) the position of the diffuser vane 61 with the projection 64b of the unison ring 64 applied to the stopper 70 when the internal combustion engine 1 is started. The position of the diffuser vane 61 at this time is set as a reference position. That is, since the diffuser vane 61 is fully closed when the protrusion 64b of the unison ring 64 is in contact with the stopper 70, the position at this time is stored as the fully closed position of the diffuser vane 61. In this way, the reference position of the diffuser vane 61 is learned. The current VGD opening is calculated by calculating how much the diffuser vane 61 has moved from the reference position based on the operating state of the actuator 57.

However, since the amount of change in the VGD opening obtained from the operating state of the actuator 57 includes an error, if the time during which the internal combustion engine 1 is operating increases, the calculated value and the actual value of the VGD opening Deviation may occur. Then, the actual value of the VGD opening (hereinafter referred to as the actual VGD opening) deviates from the target value (hereinafter referred to as the target VGD opening), and the compressor efficiency may deviate from the target value. Further, when the diffuser vane 61 is lost, the compressor efficiency may be out of the target value. Even if these abnormalities occur, since the change in the supercharging pressure is small, these abnormalities are difficult to detect. In addition, if there is a deviation between the calculated value of the VGD opening and the actual value, the reference position of the diffuser vane 61 may be stored again. A warning is required. For this reason, it is necessary to distinguish both. The target VGD opening is set according to, for example, the engine speed and the boost pressure.

Therefore, in this embodiment, these abnormalities are determined based on the compressor efficiency. It should be noted that it may be confirmed in advance by other known techniques that there is no abnormality in the devices other than the turbocharger 50. Here, the compressor efficiency ηc is calculated by the following equation.
ηc = T0 × {(P3 / P0) ^0.286 −1} / (T3−T0)
However, T0 is compressor inlet temperature (temperature obtained by the inlet side temperature sensor 12), T3 is compressor outlet temperature (temperature obtained by the outlet side temperature sensor 14), and P0 is compressor inlet pressure (obtained by the inlet side pressure sensor 11). Pressure), P3 is the compressor outlet pressure (pressure obtained by the outlet side pressure sensor 13).

  Then, a compressor efficiency ηcAr (hereinafter referred to as a closed-side actual compressor efficiency ηcAr) when a predetermined intake air amount GaA when the VGD opening is closer than 50% is obtained. Similarly, a compressor efficiency ηcBr (hereinafter referred to as an open side actual compressor efficiency ηcBr) at a predetermined intake air amount GaB when the VGD opening is on the open side with respect to 50% is obtained. The VGD opening degree is 0% when the diffuser vane 61 is fully closed and 100% when the diffuser vane 61 is fully open. And the opening degree of the center between fully closed to fully open becomes 50%. The opening degree may be set based on the angle of the rotation shaft 63 or may be set based on the cross-sectional area of the passage surrounded by the adjacent diffuser vanes 61. That is, the center of the rotation range of the rotation shaft 63 may be 50% of the opening degree of the diffuser vane 61, and the center of the change range of the cross-sectional area of the passage may be 50% of the opening degree of the diffuser vane 61. Further, the predetermined intake air amount GaA when the VGD opening is closer to the closing side than 50% may be the intake air amount during the idling operation. Further, “when the VGD opening is on the closing side than 50%” may be when the diffuser vane 61 is fully closed, and “when the VGD opening is on the opening side than 50%” 61 may be fully open.

  Further, reference values for the closed side actual compressor efficiency ηcAr and the open side actual compressor efficiency ηcBr are obtained in advance by experiments or the like. This reference value is the compressor efficiency when the diffuser vane 61 is normal. The reference value of the closed side actual compressor efficiency ηcAr is set as the closed side reference compressor efficiency ηcA, and the reference value of the open side actual compressor efficiency ηcBr is set as the open side reference compressor efficiency ηcB. Further, the difference (ηcAr−ηcA) between the closed side actual compressor efficiency ηcAr and the closed side reference compressor efficiency ηcA is defined as a closed side compressor efficiency difference ΔηcA, and the difference between the open side actual compressor efficiency ηcBr and the open side reference compressor efficiency ηcB ( (ηcBr−ηcB) is defined as an open side compressor efficiency difference ΔηcB.

  Since the closed side compressor efficiency difference ΔηcA and the open side compressor efficiency difference ΔηcB vary depending on the abnormal state of the diffuser vane 61, the abnormal state of the diffuser vane 61 is determined based on these values.

Here, FIG. 4 is a diagram showing the relationship between the intake air amount and the pressure ratio when the VGD opening is closer to the closing side than 50%. FIG. 5 is a graph showing the relationship between the intake air amount and the pressure ratio when the VGD opening is on the open side of 50%. The pressure ratio is a value (P3 / P0) obtained by dividing the pressure P3 downstream from the compressor housing 51 by the pressure P0 upstream from the compressor housing 51. The solid line indicates the efficiency contour, and the alternate long and short dash line indicates the surge limit. The region on the right side of the surge limit is a region where the turbocharger 50 can be operated stably without being affected by the surge. The area on the left side of the surge limit is
This is a region where the operation of the turbocharger 50 becomes unstable due to the influence of a surge. Also, the compressor efficiency is higher in the inner region than in the efficiency contour than in the outer region.

  Further, the pressure ratio when the VGD opening degree is a predetermined intake air amount GaA when the opening is closer than 50% is defined as a closed-side actual pressure ratio πcA. Similarly, the pressure ratio when the VGD opening degree is a predetermined intake air amount GaB when the opening is more than 50% is defined as an open side actual pressure ratio πcB. The closed side actual pressure ratio πcA is smaller than the open side actual pressure ratio πcB.

  As can be seen from a comparison between FIG. 4 and FIG. 5, the region where the compressor efficiency is high varies depending on the VGD opening, and the region where the VGD opening is on the closed side and the compressor efficiency is narrower than on the open side.

  Here, when an abnormality occurs in which the actual VGD opening is closer to the closing side than the target VGD opening, in a region where the intake air amount is small, the actual VGD opening becomes the closing side and the compressor efficiency increases. Conceivable. On the other hand, when there is an abnormality in which the actual VGD opening is closer to the closing side than the target VGD opening, it is considered that in a region where the intake air amount is large, the flow rate of the intake air is limited and the compressor efficiency is lowered.

  FIG. 6 shows the intake air amount and the compressor efficiency when the VGD opening is a predetermined opening closer to the closing side than 50% when the actual VGD opening is closer to the closing side than the target VGD opening. FIG. Further, FIG. 7 shows the intake air amount and the compressor when the VGD opening is a predetermined opening on the opening side of more than 50% when an abnormality occurs where the actual VGD opening is closer to the target VGD opening. It is the figure which showed the relationship with efficiency. A solid line indicates a reference value (which may be a target value), and a broken line indicates an actual measurement value. FIG. 6 shows the relationship when the intake air amount is relatively small, and FIG. 7 shows the relationship when the intake air amount is relatively large. As can be seen from FIG. 6, the predetermined intake air amount GaA when the VGD opening is closer to the closing side than 50% is the intake air amount at which the compressor efficiency at the VGD opening is maximized. Is set to a smaller value. Similarly, as can be seen from FIG. 7, the predetermined intake air amount GaB when the VGD opening is more than 50% is the intake air that maximizes the compressor efficiency at the VGD opening at that time. It is set to a value larger than the amount. For example, the intake air amount smaller than the intake air amount at which the compressor efficiency is highest when the VGD opening is 0% can be set as the predetermined intake air amount GaA. Further, for example, the intake air amount larger than the intake air amount at which the compressor efficiency becomes highest when the VGD opening degree is 100% can be set as the predetermined intake air amount GaB.

  As shown in FIG. 6 and FIG. 7, when an abnormality occurs in which the actual VGD opening is closer to the closing side than the target VGD opening, the intake air amount is limited. Shifts to the left in FIGS. 6 and 7 with respect to the reference value. That is, when there is an abnormality in which the actual VGD opening is closer to the closing side than the target VGD opening, when the actual VGD opening is closer than 50% (see FIG. 6), the predetermined intake air amount GaA The closed-side compressor efficiency difference ΔηcA at the time becomes a positive value. Further, when an abnormality occurs in which the actual VGD opening is closer to the closing side than the target VGD opening, when the actual VGD opening is larger than 50% (see FIG. 7), the predetermined intake air amount GaB is The open side compressor efficiency difference ΔηcB at the time becomes a negative value.

Here, FIG. 8 is a diagram showing the relationship between the closed side compressor efficiency difference ΔηcA and the open side compressor efficiency difference ΔηcB when an abnormality occurs where the actual VGD opening is closer to the closing side than the target VGD opening. is there. The hatched area indicates values that can be taken by the closed side compressor efficiency difference ΔηcA and the open side compressor efficiency difference ΔηcB when an abnormality occurs in which the actual VGD opening is closer to the closing side than the target VGD opening. The range that can be said to be normal is given a certain range, and if the closed side compressor efficiency difference ΔηcA and the open side compressor efficiency difference ΔηcB are within the range of “−D” to “+ D”, respectively, the normal range. It is said to be within. This D is obtained in advance by experiments or the like as a value that defines the normal range.

  On the other hand, when an abnormality occurs in which the actual VGD opening is on the open side with respect to the target VGD opening, in a region where the intake air amount is small, the actual VGD opening is on the open side, thereby reducing the compressor efficiency. Conceivable. On the other hand, when there is an abnormality that causes the actual VGD opening to be more open than the target VGD opening, it is considered that in a region where the intake air amount is large, the resistance of the intake air decreases and the compressor efficiency increases.

  FIG. 9 shows the intake air amount and the compressor efficiency when the VGD opening is a predetermined opening on the closing side of more than 50% when an abnormality occurs where the actual VGD opening is on the opening side with respect to the target VGD opening. FIG. FIG. 10 shows the intake air amount and compressor when the VGD opening is a predetermined opening that is more than 50% open when the actual VGD opening is larger than the target VGD opening. It is the figure which showed the relationship with efficiency. A solid line indicates a reference value (which may be a target value), and a broken line indicates an actual measurement value. FIG. 9 shows the relationship when the intake air amount is relatively small, and FIG. 10 shows the relationship when the intake air amount is relatively large.

  As shown in FIG. 9 and FIG. 10, when an abnormality occurs in which the actual VGD opening is more open than the target VGD opening, the intake air amount increases, and thus the actual measured value of the compressor efficiency. Is shifted to the right side of FIGS. 9 and 10 with respect to the reference value. That is, when there is an abnormality that causes the actual VGD opening to be more open than the target VGD opening, when the actual VGD opening is closer than 50% (see FIG. 9), the predetermined intake air amount GaA The closed-side compressor efficiency difference ΔηcA at the time becomes a negative value. Further, when an abnormality occurs in which the actual VGD opening is more open than the target VGD opening, when the actual VGD opening is larger than 50% (see FIG. 10), the predetermined intake air amount GaB The open side compressor efficiency difference ΔηcB at the time becomes a positive value.

  Here, FIG. 11 is a diagram showing the relationship between the closed side compressor efficiency difference ΔηcA and the open side compressor efficiency difference ΔηcB when an abnormality occurs in which the actual VGD opening is more open than the target VGD opening. is there. The hatched area indicates the values that can be taken by the closed side compressor efficiency difference ΔηcA and the open side compressor efficiency difference ΔηcB when an abnormality occurs in which the actual VGD opening is more open than the target VGD opening. The value of D is the same as in FIG.

  When a part of the diffuser vane 61 is dropped or damaged, the intake air amount is further increased as in the case where an abnormality occurs in which the actual VGD opening is more open than the target VGD opening. Become more. For this reason, the relationship shown in FIGS. 9, 10, and 11 also applies when the diffuser vane 61 is missing.

  Further, when the compressor efficiency is reduced in the entire region, it is considered that another abnormality different from the abnormality described above has occurred. FIG. 12 is a diagram showing the relationship between the intake air amount and the compressor efficiency when the VGD opening is a predetermined opening closer to the closing side than 50% when another abnormality occurs. FIG. 13 is a diagram showing the relationship between the intake air amount and the compressor efficiency when the VGD opening degree is a predetermined opening degree that is larger than 50% when another abnormality occurs. A solid line indicates a reference value (which may be a target value), and a broken line indicates an actual measurement value. FIG. 14 is a diagram showing the relationship between the closed-side compressor efficiency difference ΔηcA and the open-side compressor efficiency difference ΔηcB when another abnormality occurs. The hatched area indicates the possible values of the closed-side compressor efficiency difference ΔηcA and the open-side compressor efficiency difference ΔηcB when another abnormality occurs. The value of D is the same as in FIG.

As described above, when another abnormality occurs, the closed side compressor efficiency difference ΔηcA when the actual VGD opening is closer than 50% (see FIG. 12) when the predetermined intake air amount is GaA.
Is negative. Further, when other abnormality occurs, on the side where the actual VGD opening is more than 50% (see FIG. 13), the open side compressor efficiency difference ΔηcB at a predetermined intake air amount GaB is a negative value. Become.

  As described above, the closed-side compressor efficiency difference ΔηcA and the open-side compressor efficiency difference ΔηcB change depending on the type of abnormality of the diffuser vane 61. Therefore, it is possible to determine where the diffuser vane 61 has a failure based on these values. it can.

  FIG. 15 is a flowchart illustrating a flow of failure detection according to the present embodiment. This routine is executed every predetermined time by the ECU 10. In this embodiment, the ECU 10 that executes the flow shown in FIG. 15 corresponds to the determination means in the present invention.

  In step S101, a closed side compressor efficiency difference ΔηcA is calculated. In step S102, an open side compressor efficiency difference ΔηcB is calculated.

  In step S103, it is determined whether or not the closed side compressor efficiency difference ΔηcA is larger than “0 + predetermined value D” and the open side compressor efficiency difference ΔηcB is smaller than “0−predetermined value D”. The predetermined value D is a value obtained by experiments or the like as a value indicating the range of the closed side compressor efficiency difference ΔηcA and the open side compressor efficiency difference ΔηcB when the diffuser vane 61 is normal. That is, in this step, the compressor efficiency when the predetermined intake air amount GaA when the VGD opening is closer than 50% is larger than the normal range of the compressor efficiency, and the VGD opening is more than 50%. It is determined whether or not the compressor efficiency at a predetermined intake air amount GaB on the open side is smaller than the normal range of the compressor efficiency. If an affirmative determination is made in step S103, the process proceeds to step S104, where it is determined that an abnormality has occurred where the actual VGD opening is closer to the target VGD opening. On the other hand, if a negative determination is made in step S103, the process proceeds to step S105.

  In step S105, it is determined whether or not the closed-side compressor efficiency difference ΔηcA is smaller than “0−predetermined value D” and the open-side compressor efficiency difference ΔηcB is larger than “0 + predetermined value D”. That is, in this step, the compressor efficiency when the VGD opening is closer to the closing side than 50% and the predetermined intake air amount GaA is smaller than the normal range of the compressor efficiency, and the VGD opening is less than 50%. It is determined whether or not the compressor efficiency at the predetermined intake air amount GaB on the open side is larger than the normal range of the compressor efficiency. If an affirmative determination is made in step S105, the process proceeds to step S106, where it is determined that an abnormality has occurred where the actual VGD opening is more open than the target VGD opening, or that the diffuser vane 61 has been lost. On the other hand, if a negative determination is made in step S105, the process proceeds to step S107.

  In step S107, it is determined whether or not the closed side compressor efficiency difference ΔηcA is smaller than “0−predetermined value D” and the open side compressor efficiency difference ΔηcB is smaller than “0−predetermined value D”. That is, in this step, the compressor efficiency when the VGD opening is closer to the closing side than 50% and the predetermined intake air amount GaA is smaller than the normal range of the compressor efficiency, and the VGD opening is less than 50%. It is determined whether or not the compressor efficiency at a predetermined intake air amount GaB on the open side is smaller than the normal range of the compressor efficiency. If an affirmative determination is made in step S107, it is determined that another abnormality that causes a reduction in compressor efficiency has occurred. On the other hand, if a negative determination is made in step S107, the diffuser vane 61 is normal and this routine is terminated.

If it is determined that an abnormality has occurred where the actual VGD opening is closer to the closing side than the target VGD opening (when step S104 is executed), then the actual VGD opening is set to the target VG.
Reference position learning control to match the D opening is executed. That is, the actuator 57 is operated until the protrusion 64b of the unison ring 64 hits the stopper 70, and the position at this time is stored. At this time, since the diffuser vane 61 is fully closed, the position at this time is stored as the fully closed position of the diffuser vane 61. Thereafter, the VGD opening degree is controlled based on the newly stored position. In this embodiment, the ECU 10 that performs the reference position learning control corresponds to the learning means in the present invention.

  In addition, when it is determined that there is an abnormality that causes the actual VGD opening to be larger than the target VGD opening or that the diffuser vane 61 is missing (when step S106 is executed), first, the actual VGD is opened. Reference position learning control for adjusting the opening to the target VGD opening is executed. That is, the actuator 57 is operated until the protrusion 64b of the unison ring 64 hits the stopper 70, and the position at this time is stored. At this time, since the diffuser vane 61 is fully closed, the position at this time is stored as the fully closed position of the diffuser vane 61. Thereafter, the VGD opening degree is controlled based on the newly stored position. Then, after that, the flow shown in FIG. 15 is executed again. As a result, when there is no abnormality in the diffuser vane 61, an abnormality has occurred in which the actual VGD opening is more open than the target VGD opening. However, it is considered that the abnormality has been eliminated by the reference position learning control. On the other hand, even when the flow shown in FIG. 15 is executed again, if it is determined that there is an abnormality that causes the actual VGD opening to be larger than the target VGD opening or that the diffuser vane 61 is missing, It is determined that the diffuser vane 61 is missing. That is, since the abnormality is not resolved by the reference position learning control, it is considered that the diffuser vane 61 has been lost rather than an abnormality in which the actual VGD opening is more open than the target VGD opening. In this case, for example, a warning light is turned on to notify the driver of the abnormality. At this time, the operation shifts to a fail safe mode in which the output of the internal combustion engine 1 is suppressed. In the fail safe mode, the amount of fuel supplied to the internal combustion engine 1 is limited or the supercharging pressure is limited.

  By the way, in the present embodiment, a predetermined intake air amount GaA when the VGD opening is closer to the closing side than 50% and a predetermined intake air amount GaB when the VGD opening is the opening side from 50%. Failure detection cannot be performed unless the operating state is such that two intake air quantities can be obtained. On the other hand, the predetermined intake air amount serving as a determination criterion may be set to be larger so that failure detection can be performed based on the intake air amount obtained in another operating state. If a reference value for compressor efficiency is previously determined for each intake air amount, failure detection can be performed in a wider operating range.

  As described above, according to this embodiment, the type of abnormality of the diffuser vane 61 can be determined based on the compressor efficiency. Thereby, an appropriate treatment can be performed.

1 Internal combustion engine 2 Cylinder 2A Intake port 2B Exhaust port 3 Intake passage 4 Exhaust passage 10 ECU
11 Inlet side pressure sensor 12 Inlet side temperature sensor 13 Outlet side pressure sensor 14 Outlet side temperature sensor 15 Air flow meter 16 Crank position sensor 50 Turbocharger 51 Compressor housing 52 Turbine housing 53 Center housing 54 Compressor impeller 55 Turbine impeller 56 Rotor shaft 57 Actuator 58 Link rod 60 Variable diffuser 61 Diffuser vane 62 Base plate 63 Rotating shaft 64 Unison ring 64a Notch 64b Protrusion 65 Followed arm 66 Guide roller 70 Stopper

Claims (5)

In a failure detection device for an internal combustion engine provided with a supercharger having a variable diffuser for changing the angle of a diffuser vane in a compressor part,
Compressor efficiency when the intake air amount of the internal combustion engine is smaller than a first predetermined value, and compressor efficiency when the intake air amount of the internal combustion engine is larger than a second predetermined value larger than the first predetermined value; A failure detection device for an internal combustion engine having a supercharger, comprising: a determination unit that determines an abnormal state of the diffuser vane based on   The determination means is configured such that the compressor efficiency when the intake air amount of the internal combustion engine is smaller than the first predetermined value is larger than the normal range of the compressor efficiency, and the intake air amount of the internal combustion engine is the second predetermined value. When the compressor efficiency when the pressure is larger than the normal range of the compressor efficiency is smaller than the normal range of the compressor efficiency, it is determined that the actual opening degree of the diffuser vane is shifted to the closing side from the target opening degree. An internal combustion engine failure detection apparatus comprising the supercharger according to Item 1.   The learning device comprises learning means for learning the position of the diffuser vane when it is determined by the determining means that the actual opening of the diffuser vane is shifted closer to the closing side than the target opening. An internal combustion engine failure detection apparatus comprising the supercharger according to claim 2.   The determination means has a compressor efficiency when the intake air amount of the internal combustion engine is smaller than the first predetermined value, and the intake air amount of the internal combustion engine is less than the second predetermined value. When the compressor efficiency is larger than the normal range of the compressor efficiency, it is determined that the actual opening degree of the diffuser vane is shifted to the opening side from the target opening degree or the diffuser vane is missing. A failure detection apparatus for an internal combustion engine comprising the supercharger according to any one of claims 1 to 3. Learning means for learning the position of the diffuser vane when it is determined by the determining means that the actual opening of the diffuser vane is shifted to the open side from the target opening or the diffuser vane is missing; ,
The determination means has a compressor efficiency when the intake air amount of the internal combustion engine is smaller than the first predetermined value even after learning the position of the diffuser vane by the learning means. Determining that the diffuser vane is missing if the compressor efficiency is smaller and the compressor efficiency when the intake air amount of the internal combustion engine is greater than the second predetermined value is greater than the normal range of the compressor efficiency. An internal combustion engine failure detection apparatus comprising the supercharger according to claim 4.

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