JP2017129060A - Control device for on-vehicle internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an on-vehicle internal combustion engine that can inhibit a driver of a vehicle from feeling uncomfortable caused by introduction of part of air from a downstream side to an upstream side of a compressor to suppress generation of condensation water by raising a temperature in an intake passage.SOLUTION: A control device 10 includes: an EGR control unit 11; a bypass control unit 12; an engine control unit 13 for controlling an engine operation according to an operation mode; and a mode detection unit 14 for detecting a mode selected by a driver. When an intake temperature detected by a temperature sensor 81 is less than a specified temperature, the control device 10 performs compressor loop control for recirculating air to the upstream side of a compressor 51 while performing supercharging by using an exhaust turbine type supercharger 50. When an economy mode is not selected, even if the intake temperature is less than the specified temperature, the control device does not execute the compressor loop control.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for an in-vehicle internal combustion engine that controls an in-vehicle internal combustion engine mounted on a vehicle as a driving force source.

  2. Description of the Related Art An on-board internal combustion engine equipped with an exhaust turbine supercharger, and an internal combustion engine having a low-pressure loop EGR mechanism that recirculates exhaust gas from a downstream side of a turbine in an exhaust passage to an upstream side of a compressor in an intake passage is known. Yes. In such an internal combustion engine, when EGR gas, which is exhaust gas recirculated by the low-pressure loop EGR mechanism, merges with the air in the intake passage, the temperature may decrease and condensed water may be generated. In Patent Document 1, in order to suppress the generation of condensed water, when the temperature detected by the temperature sensor provided in the intake passage is lower than a predetermined temperature, the compressor is more downstream than the compressor in the intake passage. A control device for an internal combustion engine that introduces part of air upstream is disclosed. The internal combustion engine controlled by the control device includes an air bypass passage that connects the downstream side and the upstream side of the compressor in the intake passage, and an air bypass passage as an air bypass mechanism that introduces air upstream of the compressor. And a bypass valve that opens and closes.

  In the control apparatus for an internal combustion engine disclosed in Patent Document 1, when the detected temperature in the intake passage is lower than a predetermined temperature, the bypass valve is opened, and a part of the air supercharged by the compressor is Compressor loop control is performed to recirculate upstream of the compressor in the intake passage and to repeat adiabatic compression of air. As described above, the adiabatic compression is repeated through the compressor loop control to increase the temperature of the air passing through the compressor, thereby increasing the temperature in the intake passage through which the EGR gas is introduced.

JP2015-129457A

  If the compressor loop control is executed as described above, the temperature in the intake passage can be raised to suppress the generation of condensed water when the EGR gas is introduced, or to evaporate the generated condensed water. it can. However, when a part of the air compressed by the compressor is introduced from the downstream side to the upstream side of the compressor, a desired supercharging pressure cannot be obtained and the output of the internal combustion engine is reduced. Therefore, there is a concern that the driver of the vehicle may feel uncomfortable when executing the compressor loop control.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
A control device for an in-vehicle internal combustion engine for solving the above-mentioned problems is applied to an in-vehicle internal combustion engine mounted on a vehicle as a driving force source. The on-vehicle internal combustion engine includes an exhaust turbine supercharger, a low-pressure loop EGR mechanism, an air bypass mechanism that recirculates air from the downstream side to the upstream side of the compressor of the exhaust turbine supercharger in the intake passage, And a temperature sensor provided on the downstream side of the compressor in the passage. The control device for the in-vehicle internal combustion engine controls the low-pressure loop EGR mechanism to adjust the amount of exhaust gas recirculated to the intake passage, and controls the air bypass mechanism to recirculate upstream of the compressor. A bypass control unit that adjusts an amount of air to be discharged, and when the intake air temperature detected by the temperature sensor is lower than a specified temperature, the exhaust turbine supercharger performs supercharging while upstream of the compressor. Compressor loop control is performed to return air to the side. Furthermore, a mode detection unit that detects which mode is selected by the driver from among a plurality of operation modes including an economy mode that suppresses fuel consumption more than other modes, and a mode that is selected An engine control unit that performs engine operation control, and when the economy mode is not selected, the compressor loop control is not executed even if the intake air temperature detected by the temperature sensor is lower than the specified temperature. This is the gist.

  In the above configuration, when the economy mode is not selected, the compressor loop control is not executed, and the compressor loop control is executed only when the economy mode is selected. If the economy mode is selected, it can be said that the driver desires engine operation control giving priority to suppression of fuel consumption. In such a situation, even if the supercharging pressure decreases and the output of the internal combustion engine decreases as a part of the air is introduced from the downstream side of the compressor to the upstream side, This mode selection makes it easy to recognize that the engine operation control is given priority to the suppression of fuel consumption. Therefore, it is possible to suppress the driver from feeling uncomfortable when executing the compressor loop control.

The schematic diagram which shows the control apparatus which is one Embodiment of the control apparatus of a vehicle-mounted internal combustion engine, and the internal combustion engine which is the control object of the said control apparatus. The flowchart which shows the process which the control apparatus concerning the embodiment performs. The flowchart which shows the process which the control apparatus concerning the embodiment performs when normal mode is selected.

Hereinafter, a control device 10 that is an embodiment of a control device for an in-vehicle internal combustion engine will be described with reference to FIGS.
An internal combustion engine 20 that is a control target of the control device 10 will be described with reference to FIG. The internal combustion engine 20 is an in-vehicle internal combustion engine mounted on a vehicle as a driving force source. The internal combustion engine 20 includes a plurality of cylinders. The internal combustion engine 20 introduces air into the cylinder from the intake passage 30. The intake passage 30 is provided with a throttle valve 31 for adjusting the amount of air introduced into each cylinder. Further, the internal combustion engine 20 discharges exhaust from the cylinder through the exhaust passage 40.

  In the middle of the exhaust passage 40, an exhaust turbine supercharger 50 that rotates the turbine 52 using the flow of exhaust is provided. The exhaust turbine supercharger 50 includes a compressor 51 that is driven as the turbine 52 rotates. The compressor 51 is provided on the upstream side of the throttle valve 31 in the intake passage 30.

  The intake passage 30 is provided with an air bypass mechanism 70 that allows the upstream side and the downstream side of the compressor 51 to communicate with each other. The air bypass mechanism 70 includes an air bypass passage 71 and a bypass valve 72. The air bypass passage 71 connects the upstream side of the compressor 51 in the intake passage 30 and the downstream side of the compressor 51 in the intake passage 30. The bypass valve 72 is provided in the air bypass passage 71. When the bypass valve 72 is open, a path connecting the intake passage 30 upstream of the compressor 51 and the intake passage 30 downstream is formed, and air passes through the air bypass passage 71. The opening degree of the bypass valve 72 is controlled by an electric actuator.

  The internal combustion engine 20 includes a low-pressure loop EGR mechanism 60 that recirculates exhaust gas from the exhaust passage 40 to the intake passage 30. The low pressure loop EGR mechanism 60 includes an EGR passage 61, an EGR valve 62, and an EGR cooler 63. The EGR passage 61 connects the downstream side of the turbine 52 in the exhaust passage 40 and the upstream side of the compressor 51 in the intake passage 30. The EGR valve 62 is provided in the EGR passage 61. When the EGR valve 62 is open, the exhaust gas is recirculated from the exhaust passage 40 to the intake passage 30 via the EGR passage 61. The opening degree of the EGR valve 62 is controlled by an electric actuator. Further, an EGR cooler 63 is provided on the exhaust passage 40 side of the EGR passage 61 relative to the EGR valve 62. The EGR cooler 63 is connected to a cooling water passage that constitutes a cooling system of the internal combustion engine 20, and the cooling water circulates in the EGR cooler 63. The EGR cooler 63 cools EGR gas that is exhaust gas recirculated to the intake passage 30 via the EGR passage 61.

  Further, a portion of the intake passage 30 downstream of the compressor 51, more specifically, a portion downstream of the compressor 51, a portion where the air bypass passage 71 is connected and a portion where the throttle valve 31 is provided. A temperature sensor 81 that detects the temperature of the air in the intake passage 30 is provided between the two. The temperature sensor 81 is connected to the control device 10. A detection signal from the temperature sensor 81 is input to the control device 10.

  The control device 10 includes an EGR control unit 11 that controls the low-pressure loop EGR mechanism 60. The EGR control unit 11 controls the opening degree of the EGR valve 62 by driving the electric actuator. The amount of EGR gas passing through the EGR passage 61 is adjusted by the opening degree of the EGR valve 62.

  In addition, the control device 10 includes a bypass control unit 12 that controls the air bypass mechanism 70. The bypass control unit 12 controls the opening degree of the bypass valve 72 by driving the electric actuator. The amount of air passing through the air bypass passage 71 is adjusted by the opening degree of the bypass valve 72.

  Further, the control device 10 includes an engine control unit 13 that performs engine operation control of the internal combustion engine 20 and a mode detection unit that detects a mode selected from a plurality of operation modes for performing engine operation control of the internal combustion engine 20. 14.

Subsequently, the engine control unit 13 and the mode detection unit 14 will be described.
The engine control unit 13 is preset with an operation mode for performing engine operation control of the internal combustion engine 20. In the present embodiment, a normal mode and an economy mode are set as the operation mode. The economy mode is set as an operation mode in which the engine operation control is performed so as to suppress the fuel consumption as compared with the normal mode.

  A vehicle on which the internal combustion engine 20 is mounted includes an eco button 92. The eco button 92 is provided in the vehicle as an input device for switching the operation mode of the internal combustion engine 20 to the economy mode, and is connected to the control device 10. By pressing the eco button 92, the input state of the eco button 92 is switched, and the signal input to the mode detection unit 14 is switched. When detecting that the eco button 92 is turned on, the mode detection unit 14 outputs a command for operating the internal combustion engine 20 in the economy mode to the engine control unit 13. When it is not detected that the eco button 92 is turned on, the mode detection unit 14 outputs a command for operating the internal combustion engine 20 in the normal mode to the engine control unit 13. That is, the mode detection unit 14 detects the mode selected by the driver of the vehicle by detecting whether or not the input state of the eco button 92 is on.

  The engine control unit 13 changes the operation mode of the internal combustion engine 20 based on a command output from the mode detection unit 14. The engine control unit 13 receives a signal from an accelerator sensor 91 that detects the amount of depression of an accelerator pedal provided in the vehicle. The engine control unit 13 controls the opening degree of the throttle valve 31 based on an input signal from the accelerator sensor 91 and a command from the mode detection unit 14. That is, the engine control unit 13 controls the output of the internal combustion engine 20 by adjusting the amount of air introduced into the cylinders of the internal combustion engine 20 according to the depression amount of the accelerator pedal and the selected operation mode. When the economy mode is selected, the engine control unit 13 moderates the increase in the opening of the throttle valve 31 with respect to an increase in the amount of depression of the accelerator pedal than when the normal mode is selected. As a result, an increase in fuel consumption due to a sudden change in the opening of the throttle valve 31 is suppressed, and the fuel consumption is suppressed as compared with when the normal mode is selected.

  Next, processing executed by the control device 10 will be described with reference to FIG. This process is executed by the control device 10. This process is a routine executed at predetermined intervals. When this process is started, first, in step S101, it is determined whether or not the economy mode is selected as the operation mode of the internal combustion engine 20. This determination can be made based on the input state of the eco button 92 detected by the mode detection unit 14. That is, in step S101, it is determined that the economy mode is selected as the operation mode when the input state of the eco button 92 is on, and the economy mode is selected when the input state of the eco button 92 is off. Judge that there is no.

  When the economy mode is not selected (S101: NO), the control device 10 advances the process to step S102. In step S102, a series of processing when the engine operation control of the internal combustion engine 20 is performed based on the normal mode is executed. The series of processing in step S102 will be described later with reference to FIG. Then, when the series of processes in step S102 is finished, this routine is finished.

  On the other hand, when the economy mode is selected as the operation mode of the internal combustion engine 20 (S101: YES), the control device 10 advances the process to step S103. In step S103, it is determined whether or not the intake air temperature detected by the temperature sensor 81 is equal to or higher than a specified temperature α. Here, the specified temperature α is set as a temperature at which condensed water is not generated in the intake passage 30 even if the EGR gas merges with the air in the intake passage 30. That is, if the intake air temperature is equal to or higher than the specified temperature α, it can be estimated that condensed water is not generated in the intake passage 30 even if the EGR gas merges with the air in the intake passage 30.

  When the intake air temperature is less than the specified temperature α (S103: NO), the control device 10 advances the process to step S104. In step S104, the bypass valve 72 is opened through the bypass control unit 12. By opening the bypass valve 72, here, the compressor loop control is performed in which air is recirculated to the upstream side of the compressor 51 while being supercharged by the exhaust turbine supercharger 50. In subsequent step S105, the EGR valve 62 is closed through the EGR control unit 11. Then, this routine ends.

  On the other hand, if the intake air temperature is equal to or higher than the specified temperature α (S103: YES), the control device 10 advances the process to step S106. In step S106, the bypass valve 72 is closed through the bypass control unit 12. That is, at this time, the compressor loop control is not executed. In subsequent step S107, the EGR valve 62 is opened through the EGR control unit 11. Then, this routine ends.

  Next, a process executed when engine operation control of the internal combustion engine 20 is performed based on the normal mode will be described with reference to FIG. This process is executed by the process of step S102 in the routine described with reference to FIG. When this process is started, first, in step S201, it is determined whether or not the intake air temperature detected by the temperature sensor 81 is equal to or higher than a specified temperature α.

  When the intake air temperature is less than the specified temperature α (S201: NO), the control device 10 advances the process to step S202. In step S202, the bypass valve 72 is closed through the bypass control unit 12. In the subsequent step S203, the EGR valve 62 is closed through the EGR control unit 11. Then, this routine ends.

  On the other hand, when the intake air temperature is equal to or higher than the specified temperature α (S201: YES), the control device 10 advances the process to step S204. In step S204, the bypass valve 72 is closed through the bypass control unit 12. In the subsequent step S205, the EGR valve 62 is opened through the EGR control unit 11. Then, this routine ends.

Next, the effect of the control device 10 according to the present embodiment and the effect thereof will be described.
When the intake air temperature is low, condensed water tends to be generated as the EGR gas merges with the air in the intake passage 30. On the other hand, according to the control device 10, when the intake air temperature is lower than the specified temperature α, the EGR valve 62 is closed regardless of whether the economy mode is selected or the normal mode is selected. It is valved (step S105, step S203), and the EGR gas is not recirculated to the intake passage 30. Therefore, the generation | occurrence | production can be suppressed about the condensed water generated when EGR gas merges with the air in the intake passage 30.

  When the economy mode is selected, when the intake air temperature detected by the temperature sensor 81 is lower than the specified temperature α, the process of step S104 described with reference to FIG. Is executed. As a result, by executing the compressor loop control, the compression of the intake air can be repeated, and the temperature in the intake passage 30 can be quickly raised. When the economy mode is not selected, that is, when the normal mode is selected, the process of step S202 described with reference to FIG. 3 is executed, and the bypass valve 72 is closed. That is, in the control device 10, when the economy mode is not selected, the compressor loop control is not executed even if the intake air temperature is lower than the specified temperature α.

  Thus, the control device 10 executes the compressor loop control only when the economy mode is selected. If the economy mode is selected, it can be said that the driver desires engine operation control giving priority to suppression of fuel consumption. In such a situation, even if the supercharging pressure is reduced and the output of the internal combustion engine 20 is reduced as a part of the air is introduced from the downstream side to the upstream side of the compressor 51, the driver can This makes it easier to recognize that the engine operation control is performed with priority on the fuel consumption by selecting the mode of its own. For this reason, it is possible to suppress the driver from feeling uncomfortable with the decrease in output.

  When the economy mode is selected and the intake air temperature is lower than the specified temperature α, the temperature in the intake passage 30 can be quickly increased by executing the compressor loop control as described above. it can. Therefore, it is possible to raise the intake air temperature to the specified temperature α or higher and introduce the EGR gas into the intake passage 30 in a short period of time as compared with the case where the compressor loop control is not executed. That is, the state where the exhaust gas is not recirculated and the fuel consumption increases can be quickly resolved. Therefore, it is possible to realize engine operation control giving priority to suppression of fuel consumption in accordance with the driver's intention when the economy mode is selected.

  When the intake air temperature is equal to or higher than the specified temperature α, the EGR valve 62 is opened (step S107, step S205), both when the economy mode is selected and when the normal mode is selected. The EGR gas is returned to the intake passage 30. If the intake air temperature is equal to or higher than the specified temperature α, condensed water is hardly generated even if EGR gas is introduced into the intake passage 30. Therefore, if the intake air temperature is equal to or higher than the specified temperature α, EGR gas can be introduced into the intake passage 30 while suppressing the generation of condensed water, and the fuel consumption can be suppressed.

In addition, this embodiment can also be implemented with the following form which changed this suitably.
The control device 10 may control a display device provided in a vehicle on which the internal combustion engine 20 is mounted, display the selected operation mode, and notify the driver. With such a configuration, the driver can easily understand the selected operation mode, and the driver can be further prevented from feeling uncomfortable. Examples of the display device include a display provided in a meter panel, a display screen of a car navigation system, and the like.

  The eco button 92 may have a function for notifying the driver of the selected operation mode. For example, the eco button 92 may be provided with a display unit that displays the input state of the eco button 92, such as being lit when the input state is on. Also in this case, the driver can easily understand the selected operation mode, and the driver can be further prevented from feeling uncomfortable.

  In the above embodiment, in step S101 of FIG. 2, it is determined which operation mode is selected based on the input state of the eco button 92 detected by the mode detection unit 14. The mode detection unit 14 may determine which operation mode is selected based on the engine operation control executed by the engine control unit 13.

  As the normal mode process executed in step S102 of FIG. 2, instead of executing the process according to the routine described with reference to FIG. 3, the process of closing the bypass valve 72 and the EGR valve 62 are closed. You may perform the process to do. That is, when the economy mode is not selected, the compressor loop control may not be executed and the EGR gas may not be introduced into the intake passage 30 regardless of whether the intake air temperature is equal to or higher than the specified temperature α. Even in such a configuration, as in the above embodiment, even if the intake air temperature is less than the specified temperature α, the compressor loop control is not executed when the economy mode is not selected, and only when the economy mode is selected. Compressor loop control is executed. Therefore, it is possible to suppress the discomfort associated with introducing a part of air from the downstream side of the compressor to the upstream side to the driver of the vehicle on which the internal combustion engine is mounted. Further, since the EGR gas is introduced into the intake passage 30 only when the economy mode is selected, even if the output of the internal combustion engine 20 is reduced due to recirculation of the exhaust gas, the driver feels uncomfortable. Is suppressed.

  An operation mode other than the normal mode and the economy mode is further set, and the engine operation control of the internal combustion engine 20 is performed based on the operation mode selected from the plurality of operation modes including the normal mode and the economy mode. The control apparatus 10 to be executed may be used. In this case as well, the compressor loop control may be configured to be executed only when the economy mode that suppresses the fuel consumption is selected as compared to any other operation mode including the normal mode. Even in such a configuration, like the above-described embodiment, it is possible to give the driver of the vehicle on which the internal combustion engine 20 is mounted an uncomfortable feeling associated with introducing a part of air from the downstream side to the upstream side of the compressor. Can be suppressed.

  DESCRIPTION OF SYMBOLS 10 ... Control apparatus, 11 ... EGR control part, 12 ... Bypass control part, 13 ... Engine control part, 14 ... Mode detection part, 20 ... Internal combustion engine, 30 ... Intake passage, 31 ... Throttle valve, 40 ... Exhaust passage, 50 ... exhaust turbine type supercharger, 51 ... compressor, 52 ... turbine, 60 ... low pressure loop EGR mechanism, 61 ... EGR passage, 62 ... EGR valve, 63 ... EGR cooler, 70 ... air bypass mechanism, 71 ... air bypass passage, 72 ... Bypass valve, 81 ... Temperature sensor, 91 ... Accelerator sensor, 92 ... Eco button.

Claims (1)

From an exhaust turbine supercharger, a low-pressure loop EGR mechanism, an air bypass mechanism that recirculates air from the downstream side to the upstream side of the compressor of the exhaust turbine type supercharger in the intake passage, and the compressor in the intake passage And a temperature sensor provided on the downstream side, and is applied to an in-vehicle internal combustion engine mounted on a vehicle as a driving force source,
An EGR controller that controls the low-pressure loop EGR mechanism to adjust the amount of exhaust gas recirculated to the intake passage, and a bypass that controls the air bypass mechanism to adjust the amount of air recirculated upstream of the compressor A control unit,
On-vehicle internal combustion engine that performs compressor loop control for recirculating air to the upstream side of the compressor while supercharging by the exhaust turbine supercharger when the intake air temperature detected by the temperature sensor is lower than a specified temperature Engine control device,
Among a plurality of operation modes including an economy mode that suppresses fuel consumption more than other modes, a mode detection unit that detects which mode is selected by the driver, and an engine according to the selected mode An engine control unit that performs operation control,
A control device for an on-vehicle internal combustion engine that does not execute the compressor loop control even when the intake air temperature detected by the temperature sensor is lower than the specified temperature when the economy mode is not selected.

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