JP2008255903A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of maintaining the performance by performing a proper fail-safe when a trouble occurs in the displacement variable structure of a turbocharger having the turbine displacement variable structure and a rotation assisting structure. <P>SOLUTION: This internal combustion engine 1 comprises the turbocharger 20 having the supercharge assisting means 28 for assisting the rotation of the turbine and the turbine displacement variable means 24, 25 for varying the displacement of the turbine. The internal combustion engine further comprises a state detection means 26 for detecting the operating state of the turbine displacement variable means. The internal combustion engine also comprises a control means 30 for controlling the driving of the supercharge assisting means according to the state of the trouble when the trouble of the turbine displacement variable means is confirmed by the output of the state detection means. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an internal combustion engine (hereinafter also referred to as an engine) provided with a turbocharger. More specifically, the present invention relates to a turbine capacity variable mechanism capable of changing the capacity of the turbine and an internal combustion engine having a turbocharger provided with a rotation assist mechanism for assisting the rotation of the turbine shaft.

  2. Description of the Related Art In recent years, turbochargers that can obtain a high torque in a wide operating range have been mounted on vehicle engines. Further, an improved turbocharger (a variable capacity turbocharger) is provided so that the turbine capacity (flow rate) can be changed to obtain a high torque in a wider operating range. This variable-capacity turbocharger is equipped with an openable and closable nozzle (Variable Nozzle :) for changing the amount of exhaust gas to the turbine side of the turbocharger. By doing so, the turbine capacity can be changed as needed.

  In general, it is known that a turbocharger cannot sufficiently obtain a sufficient effect because of insufficient rotation at the time of start-up when the supercharging pressure is low, and a time lag occurs during acceleration. . In order to improve this point, a turbocharger (assisted turbocharger) having a structure for assisting the turbine rotation of the turbocharger has been proposed. In such a turbocharger with assistance, for example, an electric motor (motor) is added to the turbine shaft, and the rotational speed can be increased by driving the electric motor at the time of starting that requires assistance. For example, as disclosed in Patent Document 1, a turbocharger having both functions of variable turbine capacity and rotation assist is also known.

  However, the variable capacity turbocharger includes a movable structure for changing the turbine capacity. For this reason, the movable structure may be affected by the passage of time and may not operate correctly due to sticking of fuel or soot or wear. That is, the variable capacity turbocharger may cause various failures, and the turbine capacity may not be adjusted as designed. Therefore, Patent Document 1 proposes an internal combustion engine provided with a control means for controlling the operation of an electric motor (or a motor-generated intake air amount) so as to compensate for a change in supercharging pressure. This internal combustion engine controls the operation of an electric motor or the like so as to maintain the supercharging degree at a target value when a nozzle structure (variable nozzle device) that changes the turbine capacity fails and does not operate accurately. Therefore, even if a failure occurs in the nozzle structure, it can be dealt with by controlling the electric motor or the like.

JP 2004-92575 A

  The technique disclosed in Patent Document 1 compensates for a change in supercharging pressure by controlling an electric motor or the like when the response operability of the variable nozzle is reduced. However, the form in which the variable nozzle fails is not constant. In other words, when the variable nozzle sticks on the closed side of the target opening position (normal position), or conversely, it breaks down on the opening side of the target opening position (normal position). There are also various forms. For example, when the variable nozzle is fixed on the closed side, the pressure in the exhaust manifold becomes excessive, and inconvenience occurs such that the exhaust valve opens when the closed state should be maintained. Further, when the variable nozzle is fixed on the open side, the inside of the exhaust manifold becomes low in pressure, so that the supercharging pressure is lowered and the transient response of the internal combustion engine is lowered. However, since the technique disclosed in Patent Document 1 does not consider a specific failure mode of the variable nozzle, there is a concern that the performance of the internal combustion engine may be deteriorated depending on the generated nozzle fixing mode.

  Accordingly, an object of the present invention is to provide an internal combustion engine capable of maintaining the performance by executing an appropriate fail safe when a failure occurs in the variable capacity structure of the turbocharger having the variable turbine capacity structure and the rotation assist structure. Is to provide an institution.

  An object of the present invention is an internal combustion engine comprising a turbocharger having a supercharging assist means for assisting the rotation of the turbine and a turbine capacity varying means for making the capacity of the turbine variable, and the operation of the turbine capacity varying means State detecting means for detecting a state is further provided, and when the failure of the turbine capacity varying means is confirmed based on the output of the state detecting means, the driving of the supercharging assist means is controlled according to the state of the failure. This can be achieved by an internal combustion engine comprising control means.

  According to the present invention, the function of the internal combustion engine can be maintained because the control means performs fail-safe control of the driving of the supercharging assist means in accordance with the failure state of the turbine capacity varying means.

  Further, when the control means determines that the turbine capacity varying means has failed in a state where the exhaust manifold pressure is larger than normal, the control means controls the supercharging assist means to suppress the rise of the exhaust manifold pressure. You may make it perform control. Here, the control means may expedite the start of the braking control of the supercharging assist means when it is confirmed that the turbine capacity varying means is fixed on the closed side from the target opening.

  In addition, when the control means determines that the turbine capacity variable means has failed in a state where the exhaust manifold pressure is smaller than normal, the control means controls the supercharging assist means to perform transient response of the supercharging pressure. You may make it raise. Here, the control means may expedite the start of the drive control of the supercharging assist means when it is confirmed that the turbine capacity varying means is fixed on the opening side from the target opening.

  According to the present invention, there is provided an internal combustion engine capable of maintaining a performance by executing an appropriate fail safe when a failure occurs in a variable capacity structure of a turbocharger having a variable turbine capacity structure and a rotation assist structure. Can be provided.

  Hereinafter, an internal combustion engine (hereinafter referred to as an engine) according to an embodiment of the present invention will be described with reference to the drawings. This engine has a turbocharger provided with a supercharging assist means for assisting the rotation of the turbine shaft and a turbine capacity varying means for making the capacity of the turbine variable.

  FIG. 1 is a block diagram illustrating an engine (E / G) 1 according to an embodiment. An intake manifold 2 is provided on the intake side of the engine 1, and an exhaust manifold 3 is provided on the exhaust side. In the intake passage 4 connected to the intake manifold 2, an air cleaner 5, an intercooler 6, and a throttle valve 7 are arranged from the upstream side. Further, an air flow meter 10 for detecting an intake air flow rate (intake amount) is disposed in the intake passage 4 on the downstream side of the air cleaner 5. The output of the air flow meter 10 is supplied to an ECU 30 described later. An exhaust purification catalyst 9 is disposed downstream of the exhaust passage 8 connected to the exhaust manifold 3.

  The engine 1 is provided with a turbocharger 20. The turbine 22 of the turbocharger 20 is arranged in the middle of the exhaust passage 8, and the compressor 23 is arranged in the middle of the intake passage 4. The turbine 22 and the compressor 23 are fixed to both ends of the turbine shaft 21.

  The turbocharger 20 is formed so that the turbine capacity can be changed, and has an assist function that can increase the turbine rotational speed. A variable nozzle (variable nozzle) 24 serving as a turbine capacity variable means is provided in the vicinity of the turbine 22. A conventionally known structure can be adopted as the variable nozzle 24. As the variable nozzle 24, for example, a variable nozzle structure in which a plurality of vanes (blades) are arranged in an annular shape around the turbine 22 and these vanes can be freely opened and closed can be suitably employed. The variable nozzle 24 is opened and closed by an actuator 25. By appropriately opening and closing the variable nozzle 24, the capacity of the turbine 22 is changed. As the variable nozzle 24 is closed, the exhaust gas pressure is increased to increase the rotation of the turbine shaft 21, thereby increasing the supercharging pressure and improving the engine output.

  Driving of the actuator 25 is controlled by the ECU 30. Further, a nozzle opening sensor 26 that detects the opening of the variable nozzle 24 is provided. Therefore, the ECU 30 can detect the operating state of the variable nozzle 24 based on the output of the nozzle opening sensor 26. The output of the nozzle opening sensor 26 is supplied to the ECU 30. The ECU 30 can check the output of the nozzle opening sensor 26 and control the actuator 25 to appropriately change the opening of the variable nozzle 24.

  The turbine shaft 21 is provided with an electric motor (motor) 28 as supercharging assist means. The electric motor 28 assists (rotates) the rotation of the turbine shaft 21 when power is supplied. The driving of the electric motor 28 is also controlled by the ECU 30. Further, a rotation speed sensor 29 for detecting the rotation speed NT of a rotor (not shown) of the electric motor 28 that rotates together with the turbine shaft 21 is provided. The output of the rotation speed sensor 29 is supplied to the ECU 30. Therefore, the ECU 30 can drive and control the electric motor 28 while confirming the output of the rotation speed sensor 29.

  The engine 1 includes the ECU (Electronic Control Unit) 30 described above. The ECU 30 controls the entire engine 1 by confirming the engine speed, the accelerator opening, and the like. The ECU 30 in this embodiment monitors whether or not the variable nozzle 24 has failed based on the output of the nozzle opening sensor 26. Here, when the ECU 30 confirms that the variable nozzle 24 does not perform a normal opening / closing operation, the ECU 30 executes failure countermeasure (fail-safe) control so that the engine performance does not deteriorate. That is, the ECU 30 controls the drive of the electric motor 28 so that the failure of the variable nozzle 24 does not affect the engine 1. The fail-safe control by the ECU 30 here limits the maximum output of the electric motor 28 according to the failure state of the variable nozzle 24, for example, the fixing position of the variable nozzle 24, or the operation range (operation start timing, braking start timing, etc. ). Therefore, the engine 1 according to the embodiment can maintain the function by executing fail-safe control even when a failure occurs in the variable nozzle 24. The ECU 30 includes a memory such as a ROM (not shown). This memory stores a series of programs related to the fail-safe and data necessary for executing the programs.

  FIG. 2 is a flowchart illustrating an example of fail-safe that is executed when the ECU 30 confirms a failure (operation failure) of the variable nozzle 24. This flowchart is an example of a case where fail safe control is performed by limiting the maximum output of the electric motor according to the fixing position when an abnormality in fixing the variable nozzle 24 is confirmed. By such fail-safe control, for example, it is possible to prevent the exhaust manifold pressure from becoming excessive and to maintain the function of the engine.

  The flowchart of FIG. 2 is activated when, for example, the ignition key is turned on. First, the ECU 30 confirms the output of the nozzle opening sensor 26 together with the engine speed and the accelerator opening. More specifically, the ECU 30 controls the actuator 25 according to the state (request) of the engine 1 to open and close the variable nozzle () 24. At this time, the ECU 30 confirms the target opening requested by itself and the output of the nozzle opening sensor 26, and determines whether or not a sticking abnormality has occurred in the variable nozzle 24 (S101).

  If the ECU 30 determines in step S101 that there is no sticking abnormality, the motor 28 is driven at the maximum output (S103). In this flowchart, the maximum output means that the motor is driven at 100% of the design value as usual.

  On the other hand, if the ECU 30 determines in step S101 that there is a sticking abnormality, the current position of the variable nozzle () 24 is further confirmed from the output of the nozzle opening sensor 26 (S102). And the maximum output of the electric motor 28 is restrict | limited from the opening degree of the variable nozzle 24 (S104). By limiting the maximum output of the electric motor 28 in this way, it is possible to reliably suppress the exhaust manifold pressure from becoming excessive when, for example, the variable nozzle 24 is fixed on the closed side.

FIG. 3 is a diagram illustrating a setting example of the output restriction of the electric motor 28 that is set according to the position when the variable nozzle 24 is fixed. (A) is a chart in which when the variable nozzle 24 operates normally, the normal motor output is 100%, and the motor output (%) is changed according to the position of the opening where the variable nozzle 24 is fixed. Show. (B) shows a chart in which the maximum output value (kW) of the electric motor is changed in accordance with the opening position where the variable nozzle 24 is fixed with the maximum output value 1.5 kW in the normal state.
In addition, (A) is an example in the case of restricting the output of the motor relatively with the normal time as 100%. (B) is an example in the case of limiting the absolute output (kW) of the electric motor by setting the normal output to a maximum output value of 1.5 kW.

  The ECU 30 may employ either one of FIGS. 3A and 3B to limit the output of the electric motor. The output limits shown in FIGS. 3A and 3B are set in advance based on data obtained by simulation or the like, and may be stored in the memory area of the ECU 30 so that they can be read out appropriately.

  Hereinafter, a plurality of other examples of fail safe executed by the ECU 30 when it is confirmed that the variable nozzle 24 is firmly fixed will be described with reference to the drawings. FIG. 4 is a flowchart of another fail-safe control that is executed in consideration of the deviation from the target opening when the ECU 30 confirms that the variable nozzle 24 is firmly fixed. In the fail safe shown in FIG. 4, the ECU 30 calculates the opening degree (target opening degree) of the target variable nozzle 24 according to the state of the engine 1 and confirms the difference (positional deviation) from the fixing position. And it is an example which changes the action | operation restriction | limiting of an electric motor according to this difference, and performs fail safe. By executing such fail safe, when the variable nozzle 24 is fixed on the closed side, the output of the electric motor 28 is lowered, and on the contrary, when the variable nozzle 24 is fixed on the open side. Since the output of the electric motor 28 can be increased, the engine performance can be maintained.

  The first half (S201 to S203) of the flowchart of FIG. 4 is the same as FIG. That is, the ECU 30 checks the output of the nozzle opening sensor 26 and determines whether or not a sticking abnormality has occurred in the variable nozzle 24 (S201). If the ECU 30 determines that there is no abnormality in fixing, the motor 28 is driven as usual (S203). On the other hand, if the ECU 30 determines in step S201 that there is a sticking abnormality, the current position of the variable nozzle 24 is further confirmed from the output of the nozzle opening sensor 26 (S202).

  The processing after step S202 is different from the flowchart in FIG. The ECU 30 calculates the target opening degree of the variable nozzle 24 (S204), and changes the operation limit of the electric motor based on the difference between the current position (fixed position) and the target position (S205). In this way, by changing the operation limit of the electric motor 28 according to the difference from the target opening, fail-safe control can be realized that can cope with whether the variable nozzle 24 is stuck on the closed side or the open side due to a failure. .

  FIG. 5 is a diagram showing a modification example of the operation limit of the electric motor 28 set according to the difference between the current opening degree (fixed opening degree) and the target opening degree when the variable nozzle 24 is fixed. (A) is a chart for changing the motor output (%) according to the opening position where the variable nozzle 24 is fixed, with the motor output at the target opening being 100%. (B) is a chart for changing the maximum number of revolutions (10,000 rpm) of the electric motor according to the opening position where the variable nozzle 24 is fixed, with the maximum number of revolutions at the target opening being 12 (10,000 rpm). (A) is an example in the case of changing the operation limit of the electric motor with the normal time being 100%, and (B) is an example in the case of changing the motor rotation speed with the normal time being the maximum rotation speed 12 (10,000 rpm). is there.

  The ECU 30 may change the output limit of the electric motor by adopting either FIG. 5 (A) or (B). The restriction change data shown in FIGS. 5A and 5B may also be stored in the memory area of the ECU 30 so that it can be read out appropriately.

  Furthermore, another example of fail-safe control by the ECU 30 will be described with reference to FIGS. This fail-safe control is intended to control the electric motor with the intention of surely preventing the exhaust manifold pressure from becoming excessive when the variable nozzle 24 is fixed. FIG. 6 is a flowchart illustrating fail-safe control that is executed by the ECU 30 in consideration of the intake air amount. In the case of the flowchart shown in FIG. 6 as well, the first half (S301 to S303) is the same as that described above, and therefore a duplicate description is omitted. The processing after step S304 will be described in detail.

  The ECU 30 calculates an intake air amount (hereinafter, intake air amount Ga) from the output of the air flow meter 10 (S304). Further, the maximum intake amount (Ga_max) corresponding to the target opening is calculated (S305). Then, the maximum output (%) of the electric motor is calculated based on the difference between the calculated intake air amount Ga and the maximum intake air amount Ga_max. By limiting the driving of the electric motor based on the intake air amount as described above, fail-safe can be realized so that the exhaust manifold pressure does not become excessive.

  FIG. 7A shows the relationship between the opening when the variable nozzle 24 is fixed and the maximum intake air amount Ga_max. As shown in this figure, it is necessary to change the maximum intake air amount Ga_max small according to the opening position where the variable nozzle 24 is fixed. FIG. 7A shows that the more the variable nozzle 24 is fixed on the closing side, the higher the possibility that the exhaust manifold pressure exceeds the limit with a small intake amount. Therefore, the ECU 30 adjusts the maximum intake air amount Ga_max so that the exhaust manifold pressure does not enter the upper excessive region NG with reference to FIG.

  FIG. 7B is a diagram showing an optimal motor output (%) with respect to the difference between the intake air amount Ga and the maximum intake air amount Ga_max. The ECU 30 stores the data shown in FIGS. 7A and 7B in the memory area, and executes the fail-safe process shown in FIG. Therefore, fail safe control can be performed so that the exhaust manifold pressure does not become excessive when the nozzle is fixed, thereby maintaining the function of the engine.

  Furthermore, another failsafe control executed by the ECU 30 will be described with reference to the drawings. This fail-safe control is intended to maintain the function of the engine by adjusting the braking start timing of the electric motor according to the fixed position of the variable nozzle 24.

  FIG. 8 is a diagram showing the relationship between the pressure difference α related to the motor output restriction and the fixing position of the variable nozzle 24. When the variable nozzle 24 is operating normally, the current opening degree and the target opening degree substantially coincide. Therefore, since the difference between these opening amounts is zero (0), the pressure difference α corresponds to the center CL on the horizontal axis. The pressure difference α at this time is 8 (kPa), for example, and this is the normal value of the pressure difference α. FIG. 8 shows that when the variable nozzle 24 is fixed on the closed side, a large pressure difference α (kPa) is likely to occur. Therefore, it can be understood that the countermeasure of starting the output limit of the electric motor earlier than usual is effective when it is fixed on the closed side.

  FIG. 9 is a graph showing the relationship between the pressure difference β between the target boost pressure and the current boost pressure and the motor output (%). FIG. 9 shows the output limit (%) of the electric motor determined from the pressure difference β. It also shows that the timing for starting the output limit of the electric motor (the timing for starting the braking control) is varied depending on the pressure difference α. FIG. 9 shows that when the variable nozzle 24 is fixed on the closed side and a relatively high pressure difference α1 is generated, the output restriction of the electric motor is started early. In addition, when the variable nozzle 24 is fixed on the opening side and a relatively low pressure difference α2 is generated, the output limit of the electric motor is delayed.

  FIG. 10 is a flowchart of another fail-safe control executed in consideration of FIGS. 8 and 9 when the ECU confirms that the variable nozzle is fixed. If the ECU 30 determines in step S401 that there is no abnormality in fixing, the ECU 30 drives the electric motor 28 as usual. In this case, the motor output limit pressure difference is approximately α = 8 kPa (S403). On the other hand, when the ECU 30 determines that there is a sticking abnormality (S401), the current opening of the variable nozzle 24 is further confirmed (S402), and the target opening is calculated (S404). The ECU 30 also calculates the motor output limit pressure difference α even when it is determined that there is sticking (S405).

  The ECU 30 calculates the pressure difference β, which is the difference between the target boost pressure and the current boost pressure, for each of the cases where sticking has occurred and not (S406), and the electric motor based on the obtained pressure differences α, β. The output (%) is determined (S407). The braking timing of the motor is adjusted using the motor output (%) determined in this way. By controlling the braking start timing of the electric motor, the performance of the internal combustion engine can be maintained by fail-safe so that the exhaust manifold pressure does not become excessive.

  Furthermore, still another fail-safe control executed by the ECU 30 will be described with reference to the drawings. This fail-safe control is intended to maintain the function of the engine by correcting the operation start timing of the electric motor according to the fixed position of the variable nozzle 24.

  FIG. 11 is a diagram illustrating the relationship between the pressure difference A and the fixed position of the variable nozzle 24 according to the motor operation reference. When the variable nozzle 24 is operating normally, the current opening and the target opening almost coincide with each other, so the difference between these openings is zero (0), so the pressure corresponding to the center CL on the horizontal axis. The difference A is about 17 kPa, for example. This is the normal pressure difference A value.

  As described above, when the variable nozzle 24 is fixed on the closed side, a large value of the pressure difference A (kPa) is likely to be generated. Therefore, it is preferable to suppress the output of the motor. On the other hand, when the variable nozzle 24 is fixed on the open side, the pressure difference A (kPa) becomes small. And since a supercharging pressure falls relatively, transient response will fall and engine performance will fall. Therefore, the ECU described here corrects the operation start timing of the electric motor according to the fixing position of the variable nozzle 24. This will maintain engine performance.

  In FIG. 11, a curve CV shows a determination reference curve for the pressure difference B between the current (fixed) opening and the target opening. When the pressure difference B at the time of fixation is larger than this curve CV, the ECU starts the operation of the electric motor. By doing in this way, when the variable nozzle 24 adheres on the open side, it is possible to execute fail-safe that advances the disclosure timing of the electric motor and maintain engine performance.

  FIG. 12 is a flowchart showing fail-safe control that is executed using FIG. 11 when the ECU 30 confirms that the variable nozzle 24 is fixed. Steps S501 to S504 in the first half in FIG. 12 are substantially the same as those in FIG.

  The ECU 30 calculates the electric motor operation reference pressure difference A when it is determined in step S501 that the variable nozzle () 24 is stuck (S505). Further, the ECU 30 calculates a pressure difference B which is a difference between the target supercharging pressure and the current supercharging pressure for each of the cases where sticking occurs and does not occur (S506).

  Here, it is confirmed whether or not the calculated pressure difference B is larger than the reference pressure difference A (S507). If it is larger, the operation of the electric motor 28 is started (S508). When the variable nozzle () 24 is fixed on the open side, the pressure difference B tends to be larger than the reference pressure difference A (see FIG. 11), so that the variable nozzle () 24 is fixed on the open side and transient response occurs. The engine performance can be maintained by advancing the operation start timing of the electric motor 28 when there is a high possibility that the performance will decrease. If it is determined in step S507 that the pressure difference B is equal to or less than the reference pressure difference A, the operating state of the motor may be maintained (S509). As described above, fail-safe that maintains the performance of the internal combustion engine can also be realized by the ECU 30 performing correction to advance the operation start timing of the electric motor.

  In the embodiment described above, the variable nozzle 24 is used as the turbine capacity varying means, but the present invention is not limited to such a form. In FIG. 1, reference numeral 41 denotes a waste gate valve (WGV). The waste gate valve 41 is opened and closed by an actuator 42 so that exhaust is appropriately bypassed. The opening / closing operation of the waste gate valve 41 has the same effect as when the variable nozzle 24 is opened / closed by the turbocharger. Therefore, the waste gate valve 41 may be a turbine capacity variable means. The variable nozzle 24 and the waste gate valve 41 may be used as a turbine capacity varying means.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

It is the block diagram shown about the engine which concerns on an Example. It is a flowchart which shows an example of the fail safe performed when ECU confirms the failure of a variable nozzle. It is the figure which shows about the example of setting of the output restriction of the electric motor set up according to the position when the variable nozzle adheres, (A) is the maximum output when changing the motor output (%) The case where the value (kW) is changed is shown. FIG. 10 is a flowchart of another fail-safe control that is executed in consideration of a deviation from a target opening when the ECU confirms that the variable nozzle is fixed. It is the figure which shows about the example of a change of the electric motor operation restriction set up according to the difference of the present opening and variable opening of a variable nozzle, and (A) is when changing a motor output (%), (B) Indicates the case of changing the maximum rotation speed (10,000 rpm), 10 is a flowchart of another fail-safe control that is executed in consideration of the intake air amount when the ECU confirms that the variable nozzle is fixed. FIG. (A) shows the relationship between the opening when the variable nozzle is fixed and the maximum intake amount, and (B) shows the optimum motor output (%) with respect to the difference between the intake amount and the maximum intake amount. It is a figure. It is a figure showing about the relation between the pressure difference concerning electric motor output restriction, and the adhering position of the variable nozzle. It is the figure which showed the relationship between the pressure difference (beta) of a target supercharging pressure and the present supercharging pressure, and motor output (%). 10 is a flowchart of another fail-safe control that is executed in consideration of the intake air amount when the ECU confirms that the variable nozzle is fixed. It is a figure which shows about the relationship between the pressure difference which concerns on an electric motor operation reference | standard, and the adhering position of a variable nozzle. 12 is a flowchart showing fail-safe control that is executed using the data of FIG. 11 when the ECU confirms that the variable nozzle is fixed.

Explanation of symbols

1 engine (internal combustion engine)
3 Exhaust manifold 10 Air flow meter 20 Turbocharger 24 Variable nozzle (turbine capacity variable means)
25 Actuator 26 Nozzle opening sensor (state detection means)
28 Electric motor (supercharging assist means)
30 ECU (control means)

Claims (5)

An internal combustion engine including a turbocharger having a turbocharger having turbocharge assist means for assisting rotation of a turbine and turbine capacity variable means for making the capacity of the turbine variable,
A state detecting means for detecting an operating state of the turbine capacity varying means;
When the failure of the turbine capacity varying means is confirmed based on the output of the state detecting means, the control means is provided for controlling the driving of the supercharging assist means according to the state of the failure. An internal combustion engine. The control means controls the supercharging assist means to suppress an increase in the exhaust manifold pressure when it is determined that the turbine capacity variable means has failed in a state where the exhaust manifold pressure is larger than normal. The internal combustion engine according to claim 1. 3. The control unit according to claim 2, wherein the control unit accelerates the braking start of the supercharging assist unit when it is confirmed that the turbine capacity varying unit is fixed on the closed side from the target opening. Internal combustion engine. The control means controls the supercharging assist means to increase the transient response of the supercharging pressure when it is determined that the turbine capacity varying means has failed in a state where the exhaust manifold pressure is smaller than normal. The internal combustion engine according to claim 1. 5. The control unit according to claim 4, wherein, when it is confirmed that the turbine capacity varying unit is fixed on an opening side from a target opening, the control unit accelerates the start of operation of the supercharging assist unit. Internal combustion engine.

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