JP6361357B2 - Control device for internal combustion engine with supercharger - Google Patents

Description

 The present invention relates to a control device for an internal combustion engine provided with a supercharger.

  A turbocharger that supercharges intake air from an internal combustion engine is provided with a turbo sensor that detects the turbo rotational speed of a turbo rotating body including a turbine and a compressor, as described in Patent Document 1, for example. The turbo rotating body is provided with a plurality of blades (blades) intermittently in the circumferential direction, and the turbo sensor detects the turbo rotation speed by detecting a signal when the plurality of blades pass.

  Based on the output of the turbo sensor and the like, pressure control of the supercharger and various controls of the fuel injection amount of the internal combustion engine are performed.

JP 2013-234591 A

  However, in such a turbo rotating body, there is a possibility of causing a so-called tooth missing abnormality in which the number of teeth of the blade is reduced due to a part of the blade being damaged. When such a missing tooth abnormality occurs, the turbo rotating body may generate abnormal vibrations or cause further damage to the turbo rotating body. Therefore, the turbocharger is stopped or the turbo speed is quickly increased. It is necessary to lower it.

  On the other hand, as a form of abnormality / failure of the supercharger, in addition to such a missing tooth abnormality, a failure on the turbo sensor side and the like are also included. Even in the case of such an abnormality on the turbo sensor side, as in the case of the tooth missing abnormality described above, if the turbo rotation speed is reduced or the turbocharger is stopped, the power performance is reduced more than necessary. It will cause a drop in drivability.

  The present invention has been made in view of such circumstances, and determines and identifies so-called tooth missing abnormality in a form in which the number of teeth of a plurality of blades provided in a turbo rotating body is reduced. An object of the present invention is to provide a control device for an internal combustion engine equipped with a novel turbocharger capable of performing processing.

Therefore, an internal combustion engine control apparatus equipped with a supercharger according to the present invention includes a turbocharger having a turbo rotating body provided with a compressor for supercharging intake air, and a turbo for detecting the turbo rotational speed of the turbo rotating body. And a rotational speed detection means. The turbo rotation speed detection means detects the turbo rotation speed by detecting a signal when a plurality of blades provided at equal intervals in the circumferential direction of the turbo rotating body pass. Then, based on the signal, a so-called tooth missing abnormality in which the number of teeth of the blade of the turbo rotating body is reduced is determined and identified. Specifically, by comparing the pressure ratio at the time of missing teeth and the characteristics of the turbo rotation speed which are set and stored in advance and the current pressure ratio and the characteristics of the turbo rotation speed, the above-mentioned missing tooth abnormality is detected. The number of teeth of the reduced turbine is specified by comparing the pressure ratio and turbo speed characteristics when the plurality of teeth are missing, and the current pressure ratio and turbo speed characteristics. .

  According to the present invention, since it is possible to determine and identify a missing tooth abnormality in which the number of teeth of the blade of the turbo rotating body is reduced, an appropriate fail-safe process is performed, for example, separated from a failure on the sensor side. Can do.

The block diagram which shows the control apparatus of the internal combustion engine provided with the supercharger which concerns on one Example of this invention. The block diagram which shows simply the turbine and turbo speed sensor of a compressor. The characteristic view which shows the pulse signal of the turbo rotation speed sensor at the time of normal (A) and one tooth missing (B). The flowchart which shows the flow of control of a present Example. The characteristic view which shows the characteristic of the turbo rotation speed and pressure ratio at the time of L1 at the time of normal, L2 at the time of 1 missing teeth, and 2 missing teeth.

  Hereinafter, the present invention will be described with reference to illustrated embodiments. FIG. 1 is a configuration diagram illustrating a control device for an internal combustion engine including a supercharger according to an embodiment of the present invention. The internal combustion engine 10 is a V-type multi-cylinder internal combustion engine, and pistons 12 are slidably fitted to the cylinders 11 of the left and right banks. In the turbocharger 13, a turbine 14 provided in an exhaust passage 30 and a compressor 15 provided in an intake passage 20 are coaxially connected by a turbo shaft 16, and the turbine 14 is connected by exhaust energy. When it rotates, the compressor 15 is rotationally driven to perform supercharging. The turbine 14, the compressor 15 and the turbo shaft 16 constitute a turbo rotating body 17 that rotates integrally. The exhaust passage 30 is provided with a waste gate valve 19 in a bypass passage 18 that bypasses the turbine 14, and the boost pressure is controlled by opening and closing the waste gate valve 19 by a control unit 40 described later.

  In the intake passage 20, in order from the upstream side, an air filter 21 that collects foreign matter in the intake air, an air flow meter 22 that detects the amount of intake air, the compressor 15, and an intercooler 23 that cools the intake air. , A boost pressure sensor 27 for detecting a boost pressure (intake pressure) downstream of the compressor 15, a throttle valve 24 for adjusting the intake air amount, a fuel injection valve 25 for injecting fuel into the intake port, and an intake port. An intake valve 26 that opens and closes, and the like are provided.

  In the exhaust passage 30, an exhaust valve 31 that opens and closes an exhaust port, the turbine 14, two catalysts 32 and 33 such as a three-way catalyst, and the like are provided in order from the upstream side near the combustion chamber. An air-fuel ratio sensor 34 and an oxygen sensor 35 are provided before and after the catalyst 32 on the side. The turbocharger 13 is provided with a turbo rotational speed sensor 36 that detects the rotational speed of the compressor 15 as turbo rotational speed detection means for detecting the turbo rotational speed (rotational speed) of the turbo rotator 17.

  The control unit 40 stores and executes various engine control processes such as fuel injection control by the fuel injection valve 25 and ignition timing control by the ignition device 41. For example, the control unit 40 is based on a detection signal from the air-fuel ratio sensor 34. Perform feedback control.

FIG. 2 schematically shows the structure of the turbo rotational speed sensor 36. The compressor 15 of the turbo rotating body 17 is provided with a plurality (eight in this example) of blades 37 at regular intervals in the circumferential direction. The turbo speed sensor 36 detects a pulse signal when the plurality of blades 37 pass and outputs the pulse signal to the control unit 40. Here, the turbo rotational speed sensor 36 uses, for example, a magnetic sensor or an eddy current sensor, and is installed facing the blade 37 to detect a current change or a magnetic change when a plurality of blades 37 pass, thereby detecting the blade 37. Detect the passage of. The signal detected by the turbo rotational speed sensor 36 is generally wave-shaped, but here, in order to simplify the calculation by the control unit 40, it is converted into a pulse signal and input to the control unit. Is taking. A configuration in which a waveform of a waveform is directly input to the control unit 40 may be employed. The control unit 40 integrates the pulse signals to calculate a rotation speed of the turbo, and an abnormality determination unit that determines and identifies a so-called missing tooth abnormality in a form in which the number of teeth of the blade 37 described later is reduced. Is provided.

  FIG. 3 shows a normal state (A) in which the number of teeth of the blade 37 (eight in this example) has not decreased, and a case of one missing tooth (B) in which the number of teeth of the blade 37 has decreased by one tooth. The pulse signal characteristic output from the turbo rotation speed sensor 36 is shown. As shown in the figure, when a pulse signal corresponding to the number of normal teeth Cn (eight in this example) is detected, it is determined that the turbo rotator 17 has made one rotation. However, the detection time T2 at the time of missing one tooth is longer than the detection time T1 at the normal time by the amount of missing tooth, and as a result, the turbo rotation speed is detected low.

  Here, as will be described later, if it is possible to specify that the number of teeth has decreased when the missing tooth is abnormal, and that the number of reduced teeth can be specified, the actual turbo is reduced in anticipation of a decrease in the turbo rotational speed due to the missing tooth. The rotational speed TREVx can be obtained.

That is, the turbo rotational speed TREVx detected at the time of missing teeth is expressed by the following formula (1).
TREVx = (Cn−Cx) / Cn × TREVn (1)
Cn: number of teeth at normal time Cx: number of missing teeth TREVn: turbo speed at normal time

  FIG. 4 is a flowchart showing the flow of control according to the present embodiment, and this routine is repeatedly executed by the control unit 40 every predetermined period.

  In step S11, a turbo rotation number detection permission condition is read. In step S12, it is determined whether or not a turbo rotation number detection permission condition is satisfied. For example, the detection permission condition is not satisfied in the non-supercharging region or the acceleration / deceleration transient state, and the detection permission condition is satisfied in the steady supercharging state.

  In step S13, the pressure ratio (ratio between the discharge pressure and the suction pressure of the compressor 15) is read based on the detection signal of the supercharging pressure sensor 27. In step S14, the turbo rotation speed sensor 36 reads the turbo rotation speed.

  In step S15, based on the turbo rotation speed and the pressure ratio, it is determined whether or not the characteristic of the turbo rotation speed according to the current pressure ratio approximates the normal characteristic. This determination is made by comparing with a normal characteristic L1 which is set and stored in advance and shown in FIG. When the current characteristic is close to the normal characteristic L1 (for example, when the difference between the two is less than or equal to a predetermined value), it is determined to be normal, and the process proceeds to step S16 where the normal target boost pressure or target Calculate the turbo speed. At this time, for example, when the turbocharger needs to be stopped, the target turbo speed is set to “0”.

  On the other hand, when the current characteristic is not close to the normal characteristic L1 (for example, when the difference between the two exceeds a predetermined value), the process proceeds from step S15 to step S17, where the turbo speed for the current pressure ratio is It is determined whether or not the characteristics are close to the characteristics when one blade is missing with the blade 37 having only one tooth. This determination is made by comparing with a characteristic L2 set and stored in advance and having one missing tooth as shown in FIG. As described above, the turbo rotation speed is low when the characteristic L2 at the time of missing one tooth is compared at the same pressure ratio as compared with the normal characteristic L1.

  When the current characteristic is close to the characteristic L2 when one tooth is missing (for example, when the difference between the two is less than or equal to a predetermined value), it is determined that one tooth is missing, and the process proceeds from step S17 to step S18 to fail. The mode is shifted to the safe mode, and the target supercharging pressure or the target turbo speed when one tooth is missing is calculated. The target supercharging pressure or target turbo speed at the time of missing one tooth is set lower than the target supercharging pressure or target turbo speed at the normal time so as not to cause abnormal vibration due to missing teeth. (First fail-safe control means). Further, if necessary, the passenger is informed by a warning light or warning sound that one tooth is missing. For example, when feedback control is performed on the turbo rotation speed, the actual turbo rotation speed TREVx when one tooth is missing is obtained using the above-described equation (1).

  If the current characteristic is not the characteristic at the time of missing one tooth in step S17 (for example, if the difference between the two exceeds a predetermined value), the process proceeds to step S19, where the characteristic of the turbo speed with respect to the current pressure ratio is It is determined whether the number of teeth of the blade 37 is close to the characteristics when two teeth are missing, which is smaller by two. This determination is made by comparing with a characteristic L3 at the time of missing two teeth as shown in FIG. As shown in the figure, in the characteristic L3 when two teeth are missing, the turbo rotational speed is further reduced as compared with the characteristic L2 when one tooth is missing.

  If the current characteristic is close to the characteristic L3 at the time when two teeth are missing (for example, if the difference between the two is less than or equal to a predetermined value), it is determined that the two teeth are missing, and the process proceeds from step S19 to step S20 to fail. Shift to safe mode and calculate the target boost pressure or target turbo speed when two teeth are missing. The target supercharging pressure or target turbo speed at the time of missing two teeth is set to be lower than the target supercharging pressure or target turbo speed at the time of missing one tooth so as not to cause abnormal vibration or the like ( First fail-safe control means). In addition, if necessary, the passenger is informed of the absence of two teeth by a warning light or a warning sound. For example, when feedback control is performed on the turbo rotation speed, the actual turbo rotation speed TREVx when two teeth are missing is obtained using the above-described equation (1).

If it is determined in step S20 that the current characteristic is not close to the characteristic at the time of two missing teeth, the process proceeds to step S21, and an excess due to a reason different from the missing tooth abnormality, for example, an abnormality in the turbo rotational speed sensor 36 or the like. It determines with it being abnormal of a feeder, and performs the fail safe process according to this (2nd fail safe control means).
At this time, the target boost pressure or the target turbo rotation speed is set lower than that at the time of missing one tooth, for example, although it is suppressed lower than that at the normal time. In other words, if there is no abnormality in the turbo rotating body and blades and the turbocharger itself is determined to be normal, it is merely a problem of controllability, and the control (supercharging pressure control) mainly using the above-described supercharging pressure sensor 27 is used. It is possible to continue operation by switching. However, in this case, since the turbo rotation speed cannot be detected, the rotation speed of the turbo rotating body cannot be controlled with high accuracy. Then, a control different from that at the time of missing teeth, such as a target boost pressure close to normal, is performed. Further, if necessary, the passenger is notified of the abnormality of the turbocharger by a warning light or a warning sound.

  In this embodiment, since there are very few cases of missing three or more teeth substantially, only two missing tooth abnormalities of one missing tooth and two missing teeth are easily determined. When missing teeth of three or more teeth can occur with a certain probability, an abnormality of missing teeth of three or more teeth may be determined.

  As described above, in this embodiment, it is possible to determine and identify a missing tooth abnormality in which the number of teeth of the blade 37 of the turbo rotating body 17 is reduced based on the turbo speed. Separates minor abnormalities that do not interfere with the operation of the turbocharger itself, such as malfunctions, and tooth missing abnormalities that require a reduction in turbo speed or supercharging pressure or stop the turbocharger・ Can be distinguished. For this reason, an appropriate fail-safe process such as lowering the target supercharging pressure or target turbo speed (or stopping the supercharger) is performed at the time of missing teeth, and abnormal vibration of the turbo rotator 17 is caused. For example, to reduce the turbo speed more than necessary or stop the turbocharger in the case of a minor abnormality such as a temporary malfunction or failure of the turbo speed sensor 36 while ensuring safety by suppressing it. Therefore, it is possible to minimize a decrease in power performance.

  Particularly in this embodiment, the characteristics at the time of missing one tooth and the characteristics at the time of missing two teeth are set and stored in advance, and these characteristics are compared with the current characteristics, so that it is reduced when there is a missing tooth error. The number of teeth can be specified with high accuracy. Therefore, the fail-safe process can be appropriately performed in a form corresponding to the reduced number of teeth. In other words, as the number of missing teeth increases, the decrease in the turbo rotation speed or supercharging pressure is set larger to appropriately and reliably suppress the occurrence of abnormal vibration, etc., and improve the durability and reliability of the turbocharger. Can be improved.

  Furthermore, by using the above-described equation (1), the current turbo rotational speed TREVx can be obtained with high precision in anticipation of a decrease in the turbo rotational speed corresponding to the missing tooth even when the tooth is missing. Therefore, it is possible to accurately feedback control the turbo rotational speed even when there is a missing tooth.

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine 13 ... Turbocharger 14 ... Turbine 15 ... Compressor 16 ... Turbo shaft 17 ... Turbo rotating body 36 ... Turbo speed sensor (turbo speed detection means)
40. Control unit

Claims (5)

A turbocharger having a turbo rotating body with a compressor for supercharging intake air;
Turbo rotational speed detection means for detecting the turbo rotational speed of the turbo rotator,
The turbo rotation speed detection means detects the turbo rotation speed by detecting a signal when a plurality of blades provided at equal intervals in the circumferential direction of the turbo rotating body pass,
Furthermore the missing tooth abnormalities form the number of teeth of the blade is reduced in the turbo rotation body have a abnormality determination means for determining based on the signal,
The abnormality determining means compares the pressure ratio at the time of missing teeth and the characteristics of the turbo rotation speed, which are set and stored in advance, with the current pressure ratio and the characteristics of the turbo rotation speed, thereby comparing the missing teeth. A control apparatus for an internal combustion engine having a supercharger, wherein abnormality is determined . A turbocharger having a turbo rotating body with a compressor for supercharging intake air;
Turbo rotational speed detection means for detecting the turbo rotational speed of the turbo rotator,
The turbo rotation speed detection means detects the turbo rotation speed by detecting a signal when a plurality of blades provided at equal intervals in the circumferential direction of the turbo rotating body pass,
Furthermore the missing tooth abnormalities form the number of teeth of the blade is reduced in the turbo rotation body have a abnormality determination means for determining based on the signal,
Depending on the number of reduced teeth, the pressure ratio at the time of missing teeth and the characteristics of the turbo speed are preset and stored,
The abnormality determination means identifies the reduced number of teeth of the turbine by comparing the pressure ratio and turbo speed characteristics at the time of the plurality of missing teeth with the current pressure ratio and the turbo speed characteristics. An internal combustion engine control device comprising a supercharger. 3. The apparatus according to claim 2 , further comprising fail-safe control means for performing operation by reducing the turbo rotation speed in accordance with the reduced number of teeth of the turbine when the abnormality determination means determines that the tooth missing is abnormal. The control apparatus of the internal combustion engine provided with the supercharger of description. If it is determined that the missing tooth abnormality by the abnormality determining means, according to claim 1 to 3 in which characterized in that it has a fail-safe control means for performing operation by reducing the boost pressure or the turbo rotation number The control apparatus of the internal combustion engine provided with the supercharger. Rather than missing tooth abnormality by the abnormality determining means, when it is determined that the abnormality of the turbo rotation number detecting means, having a second failsafe control means for performing a fail-safe control different from the fail-safe control means A control device for an internal combustion engine comprising the supercharger according to any one of claims 1 to 4 .

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