JP2020118050A - Control device for internal combustion engine mounted with supercharger - Google Patents

Abstract

To provide a control device of an internal combustion engine mounted with a supercharger capable of performing scavenging warm-up of an exhaust purification catalyst.SOLUTION: An electronic control device 90 is applied to an internal combustion engine 10 which comprises: a turbocharger 60; an exhaust purification catalyst 44 which is installed in an exhaust passage at a position upstream a turbine 62 to purify exhaust gas passing through the exhaust passage; and a variable nozzle device 63 which has a variable nozzle installed on the turbine 62 and is capable of variably shifting a nozzle position in a range from a fully closed position to a fully opened position. The electronic control device 90 performs catalyst warm-up control to shift the variable nozzle to the fully closed position or to a position shifted toward the fully closed position from a predetermined position.SELECTED DRAWING: Figure 1

Description

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

Patent Document 1 discloses an exhaust gas purifying apparatus for an internal combustion engine with a turbocharger (hereinafter referred to as "prior art"). In the conventional device, an exhaust gas purification catalyst that purifies the exhaust gas of the internal combustion engine is arranged upstream of the turbine.

In the conventional device, when the temperature of the exhaust gas becomes higher than the predetermined temperature, the bypass valve (waste gate valve) installed in the bypass passage bypassing the exhaust purification catalyst and the turbine is opened, and the high temperature exhaust gas is purified by the exhaust gas. By preventing the catalyst from flowing into the catalyst, it is possible to prevent the increase of the particulates. Further, in the conventional device, when it is estimated that the exhaust purification catalyst warms up to a temperature higher than the catalyst activation temperature of the exhaust purification catalyst having a low temperature by the heat of the exhaust gas, the exhaust purification catalyst is quickly warmed up. Therefore, the bypass passage is fully closed.

Japanese Patent Laid-Open No. 07-332072

In a configuration in which an exhaust purification catalyst and a bypass passage that bypasses the turbine are provided in the exhaust passage as in the conventional device, the total amount of the exhaust gas does not pass through the exhaust purification catalyst when bypassing the turbine, so the emission deteriorates.

Therefore, a configuration has been proposed in which a bypass passage is provided in the exhaust passage that branches from a predetermined position on the downstream side of the exhaust purification catalyst and on the upstream side of the turbine and that bypasses the turbine. With this configuration, the entire amount of exhaust gas passes through the exhaust purification catalyst regardless of whether the bypass valve interposed in the bypass passage is opened or closed. Furthermore, instead of the bypass valve and the bypass passage, a configuration has been proposed in which a variable nozzle device having a variable nozzle is arranged in a turbine downstream of the exhaust purification catalyst.

However, in the case of these configurations, the entire amount of exhaust gas passes through the exhaust purification catalyst regardless of whether the bypass valve (variable nozzle) is opened or closed, and therefore the control of the bypass valve of the conventional device cannot be applied as it is. There is a high possibility that early warm-up will not be possible.

The present invention has been made to address the above-mentioned problems. That is, one of the objects of the present invention is applied to an internal combustion engine with a supercharger in which an exhaust purification catalyst is arranged upstream of a turbine, and the possibility that the exhaust purification catalyst can be warmed up early can be increased. An object of the present invention is to provide a control device for an internal combustion engine with a feeder (hereinafter, also referred to as “control device of the present invention”).

A control device (90) of the present invention is provided in an exhaust passage (42) through which exhaust gas of an engine (20) passes, and a turbine (62) including a turbine wheel rotated by energy of the exhaust gas passing therethrough, and A turbocharger (60) having a compressor including a compressor wheel rotated by the turbine wheel, the turbocharger (60) being interposed in an intake passage (32) through which intake air drawn into the engine passes;
A catalyst device (44) disposed in the exhaust passage upstream of the turbine for purifying the exhaust gas passing through the exhaust passage;
A first supercharging pressure adjusting section (63), which has a variable nozzle disposed in the turbine and can set the variable nozzle within a range from a fully closed position to a fully opened position;
Or
A bypass passage (65) disposed so as to branch from a position downstream of the catalyst device and upstream of the turbine in the exhaust passage and bypassing the turbine, and a waste gate valve (66) interposed in the bypass passage. And a second supercharging pressure adjusting unit capable of setting the waste gate valve within a range from a fully closed position to a fully opened position,
It is applied to an internal combustion engine equipped with a supercharger.

The control device of the present invention is
When applied to the internal combustion engine with supercharging provided with the first supercharging pressure adjusting unit, catalyst warm-up control for setting the variable nozzle to a fully closed position or a position closer to the fully closed side than a predetermined position is executed. Is composed of
When applied to the internal combustion engine with supercharging including the second supercharging pressure adjusting unit, catalyst warm-up control for setting the waste gate valve to a fully closed position or a position fully closed from a predetermined position is executed. Is configured as follows.

According to the device of the present invention, it is possible to increase the possibility that the exhaust purification catalyst can be warmed up early.

In the above description, in order to help understanding of the present invention, the names and/or reference numerals used in the embodiments are added in parentheses to the configurations of the invention corresponding to the embodiments described later. However, each component of the present invention is not limited to the embodiment defined by the name and/or code.

FIG. 1 is a schematic configuration diagram of an internal combustion engine to which a control device for an internal combustion engine with a supercharger according to a first embodiment of the present invention is applied. FIG. 2 is a flowchart showing a routine executed by the CPU of the control device. FIG. 3 is a flowchart showing a routine executed by the CPU of the control device. FIG. 4 is a flowchart showing a routine executed by the CPU of the control device. FIG. 5 is a schematic configuration diagram of an internal combustion engine to which a control device for an internal combustion engine with a supercharger according to a second embodiment of the present invention is applied. FIG. 6 is a flowchart showing a routine executed by the CPU of the control device. FIG. 7 is a flowchart showing a routine executed by the CPU of the control device. FIG. 8 is a flowchart showing a routine executed by the CPU of the control device.

Hereinafter, a control device for an internal combustion engine with a supercharger according to each embodiment of the present invention will be described. In all the drawings of the embodiments, the same or corresponding parts are designated by the same reference numerals.

<< First Embodiment >>
<Structure>
FIG. 1 shows a schematic configuration of an internal combustion engine to which a control device for an internal combustion engine with a supercharger according to the first embodiment of the present invention (hereinafter sometimes referred to as “first control device”) is applied. .. The internal combustion engine 10 is an internal combustion engine having multiple cylinders (in this example, four cylinders of a first cylinder to a fourth cylinder). Hereinafter, for convenience, the “internal combustion engine 10” is also simply referred to as the “engine 10”.

As shown in FIG. 1, the engine 10 includes an engine body 20 (engine), an intake system 30 for introducing air into the engine body 20, and exhaust gas discharged from the engine body 20 to the outside of the engine 10. An exhaust system 40 for performing the operation, a supercharger 60 that is driven by the energy of the exhaust gas and compresses the air that is introduced into the engine body 20, various sensors 81 to 87, and an electronic control unit 90.

The engine body 20 includes a cylinder head 21 to which an intake system 30 and an exhaust system 40 are connected, an ignition device including a spark plug (not shown), an ignition coil and an igniter, and a fuel injection valve.

The ignition device is arranged on the cylinder head 21 so that its ignition plug is exposed to the combustion chamber. The ignition device is adapted to generate a spark from the ignition plug in accordance with a signal sent from the electronic control unit 90. The fuel injection valve is arranged in the intake port (not shown). The fuel injection valve is configured to inject fuel into an intake port formed in the cylinder head 21 according to a signal sent from the electronic control unit 90.

The intake system 30 includes an intake port, an intake manifold 31 that communicates with each cylinder via the intake port, an intake pipe 32 connected to the upstream manifold of the intake manifold 31, and an opening area (opening area in the intake pipe 32. A throttle valve (intake throttle valve) 33 whose cross-sectional area can be changed, a throttle valve actuator 33a for rotationally driving the throttle valve 33, an intercooler 34 and an intercooler provided in an intake pipe 32 on the upstream side of the throttle valve 33. The air cleaner 35 is provided at the end of the intake pipe 32 on the upstream side of the supercharger 60 provided on the upstream side of 34. The intake manifold 31 and the intake pipe 32 form an intake passage.

The exhaust system 40 includes an exhaust port (not shown) formed in the cylinder head 21, an exhaust manifold 41 communicating with each cylinder via the exhaust port, and an exhaust pipe connected to a downstream collecting portion of the exhaust manifold 41. 42, and an exhaust purification catalyst 44 provided upstream of the supercharger 60 provided in the exhaust pipe 42. The exhaust manifold 41 and the exhaust pipe 42 form an exhaust passage. The exhaust purification catalyst 44 is a three-way catalyst device (exhaust purification device) that carries an active component made of a noble metal such as platinum.

The supercharger 60 has a compressor 61 provided in the intake passage (intake pipe 32), a turbine 62 provided in the exhaust passage (exhaust pipe 42), and a variable nozzle device 63.

The supercharger 60 is a turbocharger and is configured to compress the air introduced into the compressor 61 (that is, the air introduced into the combustion chamber) by using the energy of the exhaust gas introduced into the turbine 62. Has been done.

Specifically, the compressor 61 has a compressor housing and a compressor wheel disposed in the compressor housing. Turbine 62 has a turbine housing and a turbine wheel disposed within the turbine housing. The turbine 62 is provided in the exhaust passage, and the turbine wheel is rotated by the energy of the exhaust gas flowing into the turbine housing. The turbine wheel and the compressor wheel are connected by a shaft (not shown), and when the turbine wheel rotates, the compressor wheel also rotates. Then, the rotation of the compressor wheel compresses the air in the intake passage downstream of the compressor 61 and sends the compressed air to the intake side of the engine body 20.

The variable nozzle device 63 includes a plurality of nozzle vanes (variable nozzles) provided on the outer circumference of the turbine wheel. The opening of the nozzle vane (hereinafter, referred to as “nozzle opening”) is changed within a range from the opening of the fully closed position to the opening of the fully opened position according to an instruction signal from the electronic control unit 90. It is supposed to be done. As a result, the opening area of the region through which the exhaust gas introduced into the turbine 62 passes is changed, and the boost pressure is changed (controlled).

When the nozzle opening of the variable nozzle is reduced, the opening area of the region through which the exhaust gas passes decreases, the flow velocity of the exhaust gas introduced into the turbine 62 increases, the recovery energy of the turbine wheel increases, and the boost pressure increases. Will increase. On the other hand, when the variable nozzle opening is increased, the opening area of the region through which the exhaust gas passes increases, the flow velocity of the exhaust gas decreases, the recovery energy of the turbine wheel decreases, and the boost pressure decreases. ..

In normal supercharging pressure control, a target for the electronic control unit 90 to control the supercharging pressure of the engine 10 (the supercharging pressure detected by the supercharging pressure sensor 83) to a target supercharging pressure according to the operating state. The nozzle opening is set and controlled so that the actual nozzle opening approaches the target nozzle opening. The target boost pressure is calculated, for example, based on the operation amount of the accelerator pedal AP (opening of the accelerator pedal AP) and the engine rotation speed.

An air introduction amount sensor 81, an intake air temperature sensor 82, a boost pressure sensor 83, a crank position sensor 84, an exhaust temperature sensor 85, a catalyst temperature sensor 86, and an accelerator opening sensor 87 are provided as the various sensors 81 to 86. ..

The air introduction amount sensor 81 is provided in the intake passage (intake pipe 32). The air introduction amount sensor 81 outputs a signal according to the mass flow rate of air flowing through the intake pipe 32 (that is, the mass of air taken into the engine 10).

The intake air temperature sensor 82 is provided in the intake passage (intake pipe 32). The intake air temperature sensor 82 outputs a signal according to the intake air temperature, which is the temperature of the air flowing through the intake pipe 32.

The supercharging pressure sensor 83 is provided in the intake pipe 32 downstream of the throttle valve 33. The supercharging pressure sensor 83 is adapted to output a signal representing the pressure of air in the intake pipe 32 (that is, the supercharging pressure provided by the supercharger 60).

The crank position sensor 84 is provided near a crankshaft (not shown). The crank position sensor 84 outputs a signal according to the rotation of the crankshaft (that is, a signal according to the engine speed).

The exhaust temperature sensor 85 is provided at a position on the upstream side of the exhaust purification catalyst 44. The exhaust gas temperature sensor 85 outputs a signal according to the temperature of the exhaust gas introduced into the exhaust gas purification catalyst 44.

The catalyst temperature sensor 86 is provided on the exhaust gas purification catalyst 44. The catalyst temperature sensor 86 outputs a signal according to the temperature of the exhaust purification catalyst 44 (hereinafter referred to as “catalyst temperature”).

The CPU 91 may obtain the catalyst temperature and the like by estimating the catalyst temperature and the like based on the operating state of the engine 10 (for example, engine load, engine speed, etc.). At least one of the exhaust temperature sensor 85 and the catalyst temperature sensor 86 may be omitted.

The accelerator opening sensor 87 is provided on the accelerator pedal AP. The accelerator opening sensor 87 outputs a signal according to the opening of the accelerator pedal AP.

The electronic control unit 90 includes a CPU 91, a ROM 92 in which programs executed by the CPU 91, tables (maps), constants, and the like are stored in advance, a RAM 93 in which the CPU 91 temporarily stores data as needed, data in a state in which power is turned on. And a backup RAM 94 that stores the stored data even while the power is cut off, and an interface 95 including an AD converter. The CPU 91, the ROM 92, the RAM 93, the RAM 94 and the interface 95 are mutually connected by a bus.

The interface 95 is connected to the various sensors described above and transmits signals output from them to the CPU 91. Further, the interface 95 is connected to the actuator 33a, the variable nozzle device 63, etc., and sends an instruction signal to them in response to an instruction from the CPU 91.

<Outline of operation>
As described above, in the configuration of the engine 10 in which the exhaust purification catalyst 44 is arranged upstream of the turbine 62, the heat of the exhaust gas discharged from the engine body 20 causes the exhaust purification catalyst 44 having a low temperature to reach the catalyst activation temperature or higher. Warm up to warm. With the configuration of this engine 10, the exhaust purification catalyst 44 is unlikely to be warmed up early. There are two possible reasons for this.
(1) The time for which the exhaust gas stays in the exhaust purification catalyst 44 is short, and the time for transferring heat from the exhaust gas to the exhaust purification catalyst 44 may be short.
(2) The exhaust gas temperature may be low.
Further, in the configuration of the engine 10 in which the exhaust purification catalyst 44 is arranged upstream of the turbine 62, there is a possibility that the emission when the warming up of the exhaust purification catalyst 44 is incomplete is deteriorated. One of the following is considered as the reason for the worsening of the emission when warm-up is not completed.
(3) The time during which the exhaust gas stays in the exhaust purification catalyst 44 is short, and the time during which the purification reaction is possible may be short.

Therefore, when the exhaust purification catalyst 44 needs to be warmed up immediately after the engine is started, the first control device sets the opening of the variable nozzle of the variable nozzle device 63 to the opening on the fully closed side (from the fully closed position or a predetermined position). Set to the fully closed position). For example, the first control device controls the variable nozzle so that the nozzle opening degree of the variable nozzle is minimized or becomes smaller than the target nozzle opening degree set during normal supercharging pressure control.

By controlling in this way, the opening area of the region through which the exhaust gas introduced into the turbine 62 downstream of the exhaust purification catalyst 44 passes becomes small, so that the exhaust purification catalyst 44 of the exhaust gas upstream of the turbine 62 is controlled. Residence time becomes longer. Therefore, the time for the exhaust gas to transfer heat to the exhaust purification catalyst 44 can be lengthened, and the warm-up of the exhaust purification catalyst 44 can be promoted.

In addition, the temperature of the exhaust gas rises as the pressure of the exhaust gas upstream of the turbine 62 rises, and the temperature of the exhaust gas in the exhaust purification catalyst 44 rises, so warming up of the exhaust purification catalyst 44 is promoted. can do.

Further, by increasing the residence time of the exhaust gas in the exhaust purification catalyst 44, the time during which the purification reaction can be performed can be lengthened, so that the emission can be reduced.
The above is the outline of the operation of the present embodiment.

<Specific operation>
The CPU 91 of the electronic control unit 90 of the first control unit (hereinafter simply referred to as "CPU91") executes the routine shown by the flowchart of FIG. 2 every time a predetermined time elapses.

Therefore, at a predetermined timing, the CPU 91 starts the process from step 200 of FIG. 2 and proceeds to step 205, where the value of the catalyst warm-up control execution flag Xs (hereinafter simply referred to as “flag Xs”). Is "0".

When the value of the flag Xs is "1", it means that the catalyst warm-up control is being executed. When the value of the flag Xs is “0”, it means that the catalyst warm-up control is not being executed. The flag Xs is set to "0" in an unillustrated initial routine executed when the ignition key switch of the vehicle is changed from off to on.

When the value of the flag Xs is 0, the CPU 91 determines “Yes” in step 205, proceeds to step 210, and determines whether the following catalyst warm-up control start condition is satisfied.

The catalyst warm-up control start condition is satisfied when either condition 1 or condition 2 is satisfied.
Condition 1: The present time is immediately after the start of the engine 10.
Condition 2: The temperature of the exhaust purification catalyst 44 (catalyst temperature) is lower than a predetermined temperature (for example, catalyst activation temperature).

If the catalyst warm-up control start condition is not satisfied, the CPU 91 makes a “No” determination at step 210 to proceed to step 295 to end the present routine tentatively.

On the other hand, when the catalyst warm-up control start condition is satisfied, the CPU 91 determines “Yes” in step 210, proceeds to step 215, and starts executing catalyst warm-up control. In this example, the CPU 91 sets the nozzle opening of the variable nozzle of the variable nozzle device 63 to the minimum. The CPU 91 may set the nozzle opening of the variable nozzle so as to be smaller than the target nozzle opening set by the normal supercharging pressure control. In addition, the CPU 91 sets the value of the flag Xs to "1". After that, the CPU 91 proceeds to step 220 and determines whether or not the catalyst warm-up control end condition is satisfied.

The catalyst warm-up control end condition is satisfied when the following condition 1 is satisfied.
Condition 1: The temperature of the exhaust purification catalyst 44 (catalyst temperature) is equal to or higher than a predetermined temperature (for example, catalyst activation temperature).
The catalyst warm-up control end condition is not limited to the above condition 1 and may be another condition.

When the catalyst warm-up control end condition is not satisfied, the CPU 91 makes a “No” determination at step 220 to proceed to step 295 to end the present routine tentatively.

After that, when the CPU 91 executes the routine of FIG. 2 and proceeds to step 205, the value of the flag Xs is “1” at the time of the processing of step 205. Therefore, the CPU 91 makes a “No” determination at step 205 to proceed to step 220, at which it determines whether or not the catalyst warm-up control termination condition is satisfied. That is, after the catalyst warm-up control is started, as long as the value of the flag Xs is “1”, the catalyst warm-up control continues to be executed, and the catalyst warm-up control is executed at step 220 every time a predetermined time elapses. It is repeatedly determined whether or not the end condition is satisfied.

Here, the catalyst warm-up control is executed, the exhaust purification catalyst 44 is heated by the heat of the exhaust gas, and the catalyst temperature rises, and the catalyst warm-up control end condition is satisfied at the time when the process of step 220 is executed. And In this case, the CPU 91 determines “Yes” in step 220, proceeds to step 225, and starts execution of normal supercharging pressure control executed in a routine not shown. As a result, the nozzle opening of the variable nozzle is controlled by the normal boost pressure control.

After that, the CPU 91 proceeds to step 230, sets the value of the flag Xs to "0", and then proceeds to step 295 to end the present routine tentatively.

As described above, according to the first control device, by minimizing the nozzle opening degree of the variable nozzle disposed in the turbine 62 downstream of the exhaust purification catalyst 44, the exhaust gas upstream of the turbine 62 The residence time in the exhaust purification catalyst 44 can be lengthened.

As a result, the time for the exhaust gas to transfer heat to the exhaust purification catalyst 44 can be lengthened, and catalyst warm-up can be accelerated. In addition, the temperature of the exhaust gas in the exhaust purification catalyst 44 rises as the pressure of the exhaust gas upstream of the turbine 62 rises, so catalyst warm-up can be promoted. By increasing the residence time of the exhaust gas in the exhaust purification catalyst 44, the time during which the purification reaction can be performed can be lengthened, so that the emission can be reduced.

<Modification 1-1>
The CPU 91 of the first control device may be configured to execute the routine shown in FIG. 3 instead of the routine shown in FIG. This routine differs from the routine shown in FIG. 2 only in that step 305 and step 310 are added between step 215 and step 220 in FIG. Therefore, the processing of steps 305 and 310 in FIG. 3 will be mainly described below.

When the catalyst warm-up control start condition is satisfied in step 210, the CPU 91 proceeds to step 215 to execute the above-described processing, and then proceeds to step 305 to determine whether or not the variable nozzle is normally closed. It should be noted that "the variable nozzle is normally closed" means that the actual nozzle opening of the variable nozzle matches or substantially matches the nozzle opening to be set in the catalyst warm-up control.

If the variable nozzle is not normally closed, the warm-up of the exhaust purification catalyst 44 is likely to weaken. Therefore, in this case, the CPU 91 determines “No” in step 305, proceeds to step 310, and executes warm-up strengthening control.

The warm-up enhancement control is control for enhancing the catalyst warm-up by controlling the engine 10 such that the engine rotation speed is higher than the normal control of the engine 10. After that, the CPU 91 proceeds to step 220 and executes the processing already described. When the condition for ending the catalyst warm-up control is “a condition that the elapsed time since the engine is started is equal to or longer than a preset threshold time”, the CPU 91 replaces the warm-up enhancement control with the catalyst. The warm-up extension control may be executed by extending the warm-up control from the time when the normal catalyst warm-up control is executed (by increasing the threshold time).

On the other hand, when the variable nozzle is normally closed, the CPU 91 determines “Yes” in step 305, proceeds to step 220, and executes the processing described above.

<Modification 1-2>
The CPU 91 of the first control device may be configured to execute the routine shown in FIG. 4 instead of the routine shown in FIG. This routine differs from the routine shown in FIG. 2 only in that steps 405 to 415 are added between step 220 and step 230 in FIG. Therefore, the processing of these steps in FIG. 4 will be mainly described below.

When the catalyst warm-up control end condition is satisfied at the time of executing the process of step 220, the CPU 91 determines “Yes” in step 220, proceeds to step 405, and proceeds to the operation pattern and vehicle surrounding environment (radar sensor). It is determined whether the vehicle is in a "state in which the vehicle is likely to accelerate" or a "state in which the vehicle is in the sports mode", based on the information acquired by the peripheral sensors such as.

The sports mode is a well-known mode in which the responsiveness of the vehicle to a driving operation is high (for example, in order to relatively enhance the responsiveness of the engine output to the operation amount of the accelerator pedal AP, the operation amount to the operation amount of the accelerator pedal AP is relatively increased. The engine output and the like are set to be relatively large (see JP 2010-20969A, JP 2010-209695A, JP 2017-024553A, etc.).

When neither of the “state in which the vehicle is likely to accelerate” and the “state in which the vehicle is in the sports mode”, the CPU 91 makes a “No” determination at step 405 to proceed to step 410, where the normal overrun is performed. Starts the supply pressure control.

On the other hand, in the case where either the “state in which the vehicle is likely to accelerate” or the “state in which the vehicle is in the sports mode” is applicable, the CPU 91 determines “Yes” in step 405 and proceeds to step 415. After advancing, the nozzle opening of the variable nozzle is maintained (maintained at a minimum) for a predetermined time, and then normal supercharging pressure control is started.

<<Second Embodiment>>
Next, a control device for an internal combustion engine with a supercharger according to a second embodiment of the present invention (hereinafter, also referred to as “second control device”) will be described.

<Structure>
FIG. 5 shows a schematic configuration of an internal combustion engine to which the second control device is applied. The configuration of this engine 10 differs from the engine 10 shown in FIG. 1 only in the points described below.
As shown in FIG. 5, the engine 10 includes a bypass passage 65 that bypasses the turbine 62 instead of the variable nozzle device 63 shown in FIG. 1, a waste gate valve 66 and an actuator interposed in the bypass passage 65. And 67.
The difference will be mainly described below.

The bypass passage 65 is a passage provided in the intake passage, and is a passage that branches from a predetermined position on the downstream side of the exhaust purification catalyst 44 and the upstream side of the turbine 62 to bypass the turbine 62. The waste gate valve 66 divides a part of the exhaust gas passing through the exhaust passage into the bypass passage 65 according to the opening degree thereof, and adjusts the flow rate of the exhaust gas introduced into the turbine 62.

The electronic control unit 90 can change the valve opening degree of the waste gate valve 66 within a range from the opening degree at the fully closed position to the opening degree at the fully opened position by driving the actuator 67. When the valve opening degree of the waste gate valve 66 is set small, the flow rate of exhaust gas introduced into the turbine 62 increases. On the other hand, when the valve opening degree of the waste gate valve 66 is set large, the flow rate of the exhaust gas introduced into the turbine 62 decreases. In normal supercharging pressure control, the electronic control unit 90 sets a target valve opening and controls the actual valve opening to approach the target valve opening.

<Specific operation>
The CPU 91 of the second control device executes the routine shown by the flowchart of FIG. 6 instead of the routine shown by the flowchart of FIG. 2 every time a predetermined time elapses. The flowchart of FIG. 6 differs from the routine shown in FIG. 2 only in that step 605 is executed instead of step 215 of FIG. Therefore, the processing of step 605 of FIG. 6 will be mainly described below.

When proceeding to step 605, the CPU 91 executes catalyst warm-up control. In this example, the CPU 91 sets the valve opening degree of the waste gate valve 66 to the minimum (sets the waste gate valve 66 to the fully closed position). The CPU 91 may set the valve opening degree of the waste gate valve 66 so as to be smaller than the target valve opening degree set by the normal supercharging pressure control. In addition, the CPU 91 sets the value of the flag Xs to "1".

As described above, according to the second control device, by minimizing the valve opening degree of the waste gate valve 66 arranged in the bypass passage 65 downstream of the exhaust purification catalyst 44, the upstream side of the turbine 62 can be controlled. The residence time of the exhaust gas in the exhaust purification catalyst 44 can be lengthened.

As a result, the time for the exhaust gas to transfer heat to the exhaust purification catalyst 44 can be lengthened, and catalyst warm-up can be promoted. In addition, the temperature of the exhaust gas in the exhaust purification catalyst 44 rises as the pressure of the exhaust gas upstream of the turbine 62 rises, so catalyst warm-up can be promoted. By increasing the residence time of the exhaust gas in the exhaust purification catalyst 44, the time during which the purification reaction can be performed can be lengthened, so that the emission can be reduced.

<Modification 2-1>
The CPU 91 of the second control device may be configured to execute the routine shown in FIG. 7 instead of the routine shown in FIG. This routine differs from the routine shown in FIG. 6 only in that steps 705 and 710 are added between steps 605 and 220 in FIG. Therefore, the processing of steps 705 and 710 of FIG. 7 will be mainly described below.

When the catalyst warm-up control start condition is satisfied in step 210, the CPU 91 proceeds to step 605 to execute the above-described processing, and then proceeds to step 705 to determine whether or not the waste gate valve 66 is normally closed. To do. Note that "the waste gate valve 66 is normally closed" means that the actual valve opening degree of the waste gate valve 66 is equal to or substantially equal to the valve opening degree that should be set by the catalyst warm-up control. Say.

When the waste gate valve 66 is not normally closed, there is a high possibility that the warm-up of the exhaust purification catalyst 44 will be weakened. Therefore, in this case, the CPU 91 makes a “No” determination at step 705 to proceed to step 710 to execute the warm-up enhancement control described above. After that, the CPU 91 proceeds to step 220 and executes the processing already described. When the condition for ending the catalyst warm-up control is “a condition that the elapsed time since the engine is started is equal to or longer than a preset threshold time”, the CPU 91 replaces the warm-up enhancement control with the catalyst. The warm-up extension control may be executed by extending the warm-up control from the time when the normal catalyst warm-up control is executed (by increasing the threshold time).

On the other hand, when the waste gate valve 66 is normally closed, the CPU 91 determines “Yes” in step 705, proceeds to step 220, and executes the above-described processing.

<Modification 1-2>
The CPU 91 of the first control device may be configured to execute the routine shown in FIG. 8 instead of the routine shown in FIG. This routine differs from the routine shown in FIG. 6 only in that steps 805 to 815 are added between step 220 and step 230 in FIG. Therefore, the processing of these steps in FIG. 8 will be mainly described below.

When the catalyst warm-up control end condition is satisfied at the time of executing the process of step 220, the CPU 91 determines “Yes” in step 220, proceeds to step 805, and proceeds to the operation pattern and the vehicle surrounding environment (radar sensor). It is determined whether the vehicle is in a "state in which the vehicle is likely to accelerate" or a "state in which the vehicle is in the sports mode", based on the information acquired by the peripheral sensors such as.

When neither of the “state in which the vehicle is likely to accelerate” and the “state in which the vehicle is in the sports mode” are applicable, the CPU 91 makes a “No” determination at step 805 to proceed to step 810, where a normal overrun is performed. Starts the supply pressure control.

On the other hand, if either of the “state in which the vehicle is likely to accelerate” and the “state in which the vehicle is in the sports mode” are applicable, the CPU 91 determines “Yes” in step 805 and proceeds to step 815. After advancing, the valve opening degree of the waste gate valve 66 is maintained (maintained at a minimum) for a predetermined time, and then execution of normal supercharging pressure control is started.

Although the respective embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments and various modifications based on the technical idea of the present invention can be adopted.

10... Internal combustion engine, 20... Engine body, 30... Intake system, 40... Exhaust system, 44... Exhaust purification catalyst, 60... Supercharger, 61... Compressor, 62... Turbine, 63... Variable nozzle device, 87... Catalyst temperature Sensor, 90... Electronic control device

Claims (1)

A turbine including a turbine wheel, which is interposed in an exhaust passage through which exhaust gas of an engine passes and is rotated by energy of the exhaust gas passing therethrough, and an intake passage through which intake air sucked into the engine passes, A turbocharger having a compressor including a compressor wheel rotated by a turbine wheel,
In the exhaust passage, a catalyst device that is disposed upstream of the turbine and that purifies the exhaust gas passing through the exhaust passage,
A first supercharging pressure adjusting unit that has a variable nozzle disposed in the turbine, and that can set the variable nozzle within a range from a fully closed position to a fully opened position;
Or
A bypass passage that is arranged so as to branch from a position downstream of the catalyst device and upstream of the turbine in the exhaust passage and that bypasses the turbine; and a waste gate valve interposed in the bypass passage, A second supercharging pressure adjusting unit capable of setting the waste gate valve within the range from the fully closed position to the fully opened position,
A control device applied to an internal combustion engine with a supercharger, comprising:
The control device is
When applied to the internal combustion engine with supercharging provided with the first supercharging pressure adjusting unit, catalyst warm-up control for setting the variable nozzle to a fully closed position or a position closer to the fully closed side than a predetermined position is executed. Is composed of
When applied to the internal combustion engine with supercharging including the second supercharging pressure adjusting unit, catalyst warm-up control for setting the waste gate valve to a fully closed position or a position fully closed from a predetermined position is executed. Configured as
Control device for internal combustion engine with supercharger.

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