JP5496057B2 - Turbocharger abnormality determination device - Google Patents

Description

  The present invention relates to a so-called variable turbocharger abnormality determination device having a turbine capable of changing an exhaust flow rate flowing through an exhaust passage.

  A turbocharger that utilizes exhaust pressure and exhaust flow rate is known as a supercharging system that enhances charging efficiency by forcibly feeding intake air into an engine combustion chamber. In this turbocharger, it is desirable to adjust the supercharging pressure in accordance with the operating state of the engine such as the rotational speed and load.

  Therefore, a vane (hereinafter referred to as a variable turbo vane) for changing the cross-sectional area of the passage for supplying exhaust to the turbine wheel is provided, and the exhaust gas flow rate is changed by changing the cross-sectional area by adjusting the angle of the variable turbo vane. A turbocharger for adjusting the supercharging pressure (hereinafter referred to as a variable turbocharger) is known and put into practical use.

  In such a variable turbocharger, a target supercharging pressure is set according to the operating state of the engine, and the variable turbo vane angle is adjusted so as to be the target supercharging pressure.

  However, in such a variable turbocharger, even if the variable turbo vane angle is adjusted to a preset angle so as to become the target supercharging pressure, the target supercharging pressure and Deviations in actual supercharging pressure (hereinafter referred to as actual supercharging pressure) may occur.

  Therefore, as a countermeasure against the deviation, Patent Document 1 discloses a technique capable of performing feedback control and determining abnormality such as aged deterioration of the turbocharger based on a deviation between the target supercharging pressure and the actual supercharging pressure. ing.

  However, in the technique disclosed in Patent Document 1, when the engine operating state changes transiently, the actual supercharging pressure may not be able to follow the change in the target supercharging pressure. is there.

  Therefore, in Patent Document 2, when the exhaust pressure itself estimated based on the operating state of the engine is lower than the threshold value, it is difficult to determine whether the turbocharger is abnormal even if the actual boost pressure exceeds the target boost pressure. This technique is disclosed. In this technique, threshold values are also provided for the intake air amount and the fuel injection amount, and when the intake air amount and the fuel injection amount are lower than the threshold values, it is difficult to make a determination higher than the turbocharger. With the technique disclosed in Patent Document 2, even when the operation of the engine changes transiently, it is difficult to make an erroneous determination regarding an abnormality of the turbocharger.

Japanese Patent Laid-Open No. 10-196381 JP 2006-291815 A

  However, in the technique disclosed in Patent Document 2, an abnormality of the turbocharger is determined based on the supercharging pressure that is a control amount of feedback control, as in the technique disclosed in Patent Document 1.

  Therefore, in any of the technologies disclosed in Patent Documents 1 and 2, there is a possibility that even if there is an abnormality in the mechanism related to feedback control, it is not possible to determine whether the abnormality is related to feedback control or the turbocharger.

  Therefore, in view of the problems of the prior art, the present invention provides a turbocharger abnormality determination device capable of determining abnormality of a variable turbocharger having a variable turbo vane without using a supercharging pressure that is a control amount of feedback control. The purpose is to provide.

In order to solve the above problems, in the present invention, a compressor provided in an intake passage of an engine and a turbine provided in an exhaust passage of the engine and capable of changing an exhaust flow rate flowing through the exhaust passage according to an operating state of the engine. In the turbocharger abnormality determination device, the EGR passage for returning a part of the exhaust gas in the exhaust passage to the intake passage, and an EGR valve for controlling the amount of EGR flowing through the EGR passage, the EGR passage and the intake passage A compressor outlet temperature sensor for detecting an intake air temperature on the downstream side of the compressor is provided upstream of an air cooler that cools intake air and upstream of an air-cooling unit, and is based on an engine speed and a fuel injection amount Usually the intake air temperature at the position provided with the compressor outlet temperature sensor when the turbocharger is normal Te A temperature calculating unit for determining, when the EGR valve is open, the ordinary intake air temperature which has been determined by the temperature calculating unit, the difference between the intake air temperature detected by the compressor exit temperature sensor, from a preset specified value And an abnormality determination unit that determines that the turbocharger is abnormal.

Thereby, in order to determine the abnormality of the turbocharger based on the intake air temperature by the compressor outlet temperature sensor, the abnormality of the variable turbocharger having the variable turbo vane is determined without using the supercharging pressure which is the control amount of the feedback control. It is possible to determine the abnormality of the turbocharger that can be used.

In addition, an EGR passage that returns a part of the exhaust gas in the exhaust passage to the intake passage is provided, and the compressor outlet temperature sensor is disposed upstream of the merging portion of the EGR passage and the intake passage and downstream of the compressor. provided Ru.

  By providing upstream of the junction and downstream of the compressor, it is possible to determine abnormality of the turbocharger based on the intake air temperature at a position not affected by the temperature, pressure, and flow rate of EGR gas. . Therefore, even when an EGR passage is provided, the invention can be easily implemented without requiring a complicated calculation for removing the influence of EGR.

Also has an air cooler for cooling the intake air downstream of the upstream and the compressor than the merging portion A on the intake passage, Ru provided with the compressor outlet temperature sensor upstream of the air cooler.

  Thereby, even when an air cooler is provided in the intake passage, it is possible to determine abnormality of the turbocharger based on the intake air temperature at a position not affected by the air cooler.

Further, when the intake manifold has an intake manifold on the intake passage, and has an intake manifold temperature sensor for detecting the temperature in the intake manifold, and the EGR valve is closed, the abnormality determination unit causes an abnormality in the turbocharger. The difference between the normal intake manifold temperature obtained using the map showing the relationship between the engine speed, the fuel injection amount, and the normal intake manifold temperature in the absence of the intake manifold temperature and the intake manifold temperature detected by the intake manifold temperature sensor is a preset specified value. If more greater, may it determined that the turbocharger is abnormal.
Generally, an intake manifold temperature sensor is provided in the intake manifold. Therefore, by using the intake manifold temperature sensor as the intake air temperature sensor, it is not necessary to add a new device in terms of hardware, and the invention can be implemented at low cost.

The abnormality determination unit may determine an abnormality between the turbocharger and the air cooler using the compressor outlet temperature sensor and the intake manifold temperature sensor when the EGR valve is closed .
In other words, an air cooler that cools intake air on the intake passage and upstream of the intake manifold and downstream of the compressor , the compressor outlet temperature sensor is added to the intake manifold temperature sensor, and the air It may be provided upstream of the cooler and downstream of the compressor.

When an air cooler is provided, the detection value by the intake manifold temperature sensor is affected by the abnormality of the air cooler in addition to the abnormality of the turbocharger. Therefore, in addition to the intake manifold temperature sensor, a temperature sensor is further added to the compressor outlet temperature sensor upstream of the air cooler and downstream of the compressor , so that a turbocharger abnormality and an air cooler abnormality are distinguished from each other. can do.
The abnormality determination unit determines whether the engine speed and the fuel injection amount are a predetermined fixed point, and the normal intake air temperature calculated by the temperature calculation unit and the compressor outlet when the predetermined fixed point is reached. The intake air temperature detected by the temperature sensor may be compared. The abnormality of the turbocharger can be judged more accurately.

  ADVANTAGE OF THE INVENTION According to this invention, the abnormality determination apparatus of the turbocharger which can determine abnormality of the variable turbocharger which has a variable turbo vane, without using the supercharging pressure which is the control amount of feedback control can be provided.

1 is a configuration diagram around an engine according to Embodiment 1. FIG. 3 is a flowchart regarding abnormality determination of the turbocharger 10 according to the first embodiment. 6 is a flowchart of another example related to abnormality determination of the turbocharger 10 according to the first embodiment.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

(Embodiment 1)
FIG. 1 is a configuration diagram around an engine according to the first embodiment.
An air supply passage 6 is connected to the engine 2 via an intake valve 32 and an intake manifold 4, and an exhaust passage 8 is connected via an exhaust valve 34. An intake manifold temperature sensor 40 for detection is provided. Further, the engine 2 is provided with injection means 38 for injecting high-pressure fuel accumulated in the common rail 36 into the engine 2.

  The intake passage 6 is provided with a compressor 10 a of a turbocharger 10. The compressor 10a is coaxially driven by a turbine 10b described later. An air cooler 12 for exchanging heat between the intake air flowing through the intake passage 4 and the atmosphere is provided downstream of the compressor 10 a in the intake passage 6, and a throttle valve 14 is provided downstream of the air cooler 12. Reference numeral 15 denotes an air flow meter for detecting the intake flow rate supplied to the compressor 10a. Further, as a characteristic configuration of the present embodiment, a compressor outlet temperature sensor 42 that detects the temperature inside the intake passage 6 and downstream of the compressor 10a is provided.

  In the exhaust passage 8, a turbine 10 b of the turbocharger 10 is provided. The turbine 10 b is driven by exhaust gas from the engine 2. Further, the turbine 10b is provided with a variable turbo vane for changing the cross-sectional area of the exhaust passage 8 in the turbine wheel, and the exhaust flow rate can be changed by changing the cross-sectional area by adjusting the angle of the variable turbo vane. It is configured. Reference numeral 26 denotes an actuator capable of adjusting the angle of the variable turbo vane.

  The exhaust passage 8 is provided with a turbine bypass line 22 that bypasses the turbine 10b, and the turbine bypass line 22 is provided with a waste gate valve 24 that adjusts the flow rate of exhaust gas flowing through the turbine bypass line. Reference numeral 28 denotes an actuator capable of adjusting the opening degree of the wastegate valve 24. Here, although the waste gate valve 24 is provided in the present embodiment, the presence or absence of the waste gate valve 24 is not particularly related to the implementation of the invention, and the invention is implemented even if the waste gate valve 24 is not provided. Is possible.

  The exhaust passage 8 is connected to an EGR passage 16 that recirculates part of the exhaust gas (EGR gas) to the intake side. The EGR passage 16 is provided with an EGR cooler 18 that cools the EGR gas and an EGR valve 20 that controls the flow rate of the EGR gas flowing through the EGR passage 16.

  In addition, a control device 50 that comprehensively controls the engine is provided. Detection results from the engine speed sensor 52, the accelerator opening sensor 54, and the like are input to the control device 50. The control device 50 can control the injection means 38 by calculating optimum values such as the fuel injection amount and the injection timing based on the engine operating state such as the input engine speed and accelerator opening. Furthermore, the control device 50 can adjust the opening degree of the EGR valve 20. Furthermore, the control device 50 can control the actuator 26 to adjust the angle of the variable nozzle vane of the turbine 10b.

In addition, the control device 50 can determine an abnormality of the turbocharger 10 such as the turbine 10b.
Hereinafter, the abnormality determination of the turbocharger 10 by the control device 50 will be described.

FIG. 2 is a flowchart regarding abnormality determination of the turbocharger 10 according to the first embodiment. FIG. 2 is a flowchart regarding abnormality determination in a state where the EGR valve 20 is open.
In step S <b> 1, the detected value of the engine speed by the engine speed sensor 52 is input to the control device 50, and the command value by the control device 50 of the fuel amount injected by the injection unit 38 is input.
When step S1 ends, the process proceeds to step S2.

In step S2, the temperature calculation unit 56 in the control device 50 outputs the normal compressor outlet temperature using the map.
Here, the map is a map showing the relationship among the engine speed, the fuel injection amount, and the normal compressor temperature when there is no abnormality in the turbocharger 10. The map is created experimentally beforehand in the engine 2 and the turbocharger 10 when there is no abnormality in the turbocharger 10.
The normal compressor outlet temperature is a compressor temperature corresponding to an operating state (engine speed, fuel injection amount) when there is no abnormality in the turbocharger 10, and is experimentally obtained in the engine 2 and the turbocharger 10. Is a value that can be.
When step S2 ends, the process proceeds to step S3.

  In step S <b> 3, the normal compressor outlet temperature output in step S <b> 2 by the abnormality determination unit 57 in the control device 50 is compared with the temperature detected by the compressor outlet temperature sensor 42.

In step S4, the abnormality determination unit 57 continues to determine that there is no abnormality if the error is less than 5% as a result of the comparison in step S3, and that the turbocharger is aged or abnormal if the error is 5% or more.
Here, the comparison in step S3 is to obtain a deviation of the compressor outlet temperature detected by the compressor outlet temperature sensor 42 with respect to the normal compressor outlet temperature.
The 5% is a specified value for determining whether or not the turbocharger used in the embodiment is abnormal, and is a value that can be appropriately determined depending on the performance of the engine and the turbocharger.

  In this embodiment, a compressor outlet temperature sensor 42 is provided at the outlet of the compressor 10a, and abnormality of the turbocharger is determined using the compressor outlet temperature. Since the outlet of the compressor 10a is before the EGR gas joins, it is not necessary to consider the influence of the EGR gas. Further, since it is on the upstream side of the air cooler 12, it is not necessary to consider the abnormality of the air cooler 12. In addition, in terms of hardware, the invention can be applied to an existing system by adding only one temperature sensor 42, so that the invention can be easily implemented at low cost.

  In addition, it is also possible to determine abnormality of the turbocharger 10 similarly using the intake manifold temperature sensor 40 generally provided without providing the compressor outlet temperature sensor 42. However, in this case, since the intake air flow rate is mixed with the EGR gas in the intake manifold 4 (corresponding to the total intake air amount), the influence of the EGR gas including the soundness of the EGR valve 20 is separated to map the temperature tendency in the intake manifold. There is a need to. However, since the intake manifold pressure (equivalent to the supercharging pressure), which may vary in the estimation of the total intake air amount, is used, it is difficult to perform the separation. Therefore, when the EGR passage 16 is used, it is preferable to determine the abnormality of the turbocharger 10 using the compressor outlet temperature in order to accurately determine the abnormality.

Furthermore, a condition can be added to more accurately determine abnormality of the turbocharger 10.
FIG. 3 is a flowchart of another example relating to abnormality determination of the turbocharger 10 according to the first exemplary embodiment.
In FIG. 3, step S11 is the same as step S1 in FIG.

  In step S12, the temperature calculation unit 56 determines whether or not the engine speed and the fuel injection amount captured in step S11 are a predetermined fixed point. Furthermore, if necessary, the injection timing from the injection means 38 is also taken in at step S11, and it can be determined whether there is a deviation from the injection pattern at the rated load.

  If there is no abnormality as a result of the determination, the normal compressor outlet temperature is output from the map using the engine speed and the fuel injection amount taken in step S11. The output of the normal compressor outlet temperature is the same as step S12 in FIG.

  Henceforth, step S13 and step S14 are the same as step S3 and step S4 in FIG.

  According to the flowchart shown in FIG. 3, the abnormality of the turbocharger 10 can be determined more accurately.

(Embodiment 2)
Next, the abnormality determination of the turbocharger 10 when the EGR valve 20 is closed or when the EGR passage 16 is not present in FIG. 1 will be described. In the second embodiment, FIG. 1 is used as a configuration diagram around the engine, and the description thereof is omitted.
In addition, the flowchart relating to the abnormality determination in this case is the same as that in FIGS. 2 and 3 when “compressor outlet temperature” is replaced with “intake manifold temperature”, and thus illustration is omitted. Here, the intake manifold temperature means the temperature in the intake manifold 4 and is a temperature that can be detected by the intake manifold thermometer 40.

  That is, in the abnormality determination of the turbocharger 10 when the EGR valve 20 is closed or when the EGR passage 16 is not present in FIG. 1, the engine speed, the fuel injection amount, and the normal intake manifold when the turbocharger 10 is normal are not detected. The normal intake manifold temperature obtained using the map showing the relationship with the temperature is compared with the intake manifold temperature detected by the intake manifold thermometer 40, and the abnormality of the turbocharger 10 is determined depending on whether or not the error is 5% or more. Judgment.

In this case, since the intake flow rate on the intake passage 6 is not mixed with the EGR gas, the intake manifold temperature is not affected by the EGR gas.
Therefore, the abnormality of the turbocharger 10 can be determined using the intake manifold temperature.

  In this case, since the intake manifold temperature is affected not only by the turbocharger 10 but also by the air cooler 12, if it is determined to be abnormal in step S4, it is determined that the turbocharger 10 or the air cooler 12 is abnormal.

  According to the second embodiment, it is not necessary to use the compressor outlet temperature sensor 42 because the abnormality of the turbocharger 10 can be determined using the intake manifold temperature. Therefore, especially when the EGR passage 16 is not provided, it is not necessary to provide the compressor outlet temperature sensor 42, and the invention can be implemented without adding equipment in terms of hardware, and it is cheap and easy to implement the invention. Is possible.

  When the EGR passage 16 is provided and the EGR valve 20 is closed to operate, the turbocharger 10 can be operated by using either the compressor outlet temperature described in the first embodiment or the intake manifold temperature described in the second embodiment. Abnormality can be judged.

Further, when the EGR passage 16 is not provided or the EGR passage 16 is provided but the EGR valve 20 is closed and operated, both the compressor outlet temperature described in the first embodiment and the intake manifold temperature described in the second embodiment are set. Combinations can also be used to determine abnormalities.
In this case, if the turbocharger 10 is abnormal, an abnormality is determined based on both the compressor outlet temperature and the intake manifold temperature. When the turbocharger 10 is normal but the air cooler 12 is abnormal, the compressor outlet temperature is determined to be normal, but the intake manifold temperature is determined to be abnormal. That is, it is possible to distinguish and determine which of the turbocharger 10 and the air cooler 12 is abnormal.

  The present invention can be used as an abnormality determination device for a turbocharger that can determine an abnormality of a variable turbocharger having a variable turbo vane without using a supercharging pressure that is a control amount of feedback control.

2 Engine 4 Intake manifold 6 Intake passage 8 Exhaust passage 10 Turbocharger 10a Turbine 10b Compressor 12 Air cooler 16 EGR passage 40 Intake manifold temperature sensor 50 Controller 56 Temperature calculation section 57 Abnormality determination section

Claims (4)

In a turbocharger abnormality determination device including a compressor provided in an intake passage of an engine and a turbine provided in an exhaust passage of the engine and capable of changing an exhaust flow rate flowing through the exhaust passage according to an engine operating state,
An EGR passage that returns a part of the exhaust gas in the exhaust passage to the intake passage, and an EGR valve that controls the amount of EGR flowing through the EGR passage,
A compressor outlet temperature sensor for detecting an intake air temperature on the downstream side of the compressor on the upstream side of the joining portion of the EGR passage and the intake passage and on the upstream side of the air cooler for cooling the intake air;
A temperature calculation unit for obtaining a normal intake air temperature at a position where the compressor outlet temperature sensor is provided when the turbocharger is normal based on an engine speed and a fuel injection amount;
When the difference between the normal intake air temperature obtained by the temperature calculation unit and the intake air temperature detected by the compressor outlet temperature sensor is larger than a predetermined value when the EGR valve is open , turbocharger abnormality determining apparatus is characterized by providing the abnormality determining section for determining a turbocharger is abnormal, the. Having an intake manifold on the air intake passage,
An intake manifold temperature sensor for detecting the temperature in the intake manifold ;
When the EGR valve is closed, the abnormality determination unit determines the normal intake manifold temperature obtained using a map showing the relationship among the engine speed, the fuel injection amount, and the normal intake manifold temperature when there is no abnormality in the turbocharger. 2. The turbocharger according to claim 1 , wherein the turbocharger is determined to be abnormal when a difference between the intake manifold temperature sensor detected by the intake manifold temperature sensor is larger than a predetermined value set in advance . Abnormality judgment device. The abnormality determination unit determines an abnormality between the turbocharger and the air cooler using the compressor outlet temperature sensor and the intake manifold temperature sensor when the EGR valve is closed. Item 3. The turbocharger abnormality determination device according to Item 2. The abnormality determination unit determines whether a predetermined fixed point is determined from the engine speed and the fuel injection amount, and the normal intake air temperature obtained by the temperature calculation unit and the compressor outlet temperature sensor when the predetermined fixed point is reached 2. The turbocharger abnormality determination device according to claim 1, wherein the abnormality is compared with the intake air temperature detected by the engine .

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