JP6128425B2 - Supercharger control device for internal combustion engine - Google Patents

Description

  The present invention relates to a supercharger control device for an internal combustion engine mounted on a vehicle or the like.

A turbocharger using exhaust gas is used to improve the output and fuel consumption of an internal combustion engine.
The supercharger drives the exhaust turbine with the exhaust gas flowing through the exhaust passage, and boosts the output of the internal combustion engine by supercharging air with a compressor connected to the exhaust turbine.

An internal combustion engine having such a supercharger is equipped with a wastegate system that bypasses exhaust gas for controlling the supercharging pressure. A bypass passage that bypasses the exhaust turbine of the supercharger is provided, and a wastegate valve is provided in the bypass passage.
And the purification apparatus which purifies exhaust gas is arrange | positioned downstream of the exhaust passage of a wastegate valve.

  For example, Patent Document 1 discloses a supercharger that switches opening and closing of a wastegate valve in accordance with an operation state of an internal combustion engine during low load operation of the internal combustion engine. This supercharger closes the wastegate valve when the driver requests acceleration. On the other hand, when it is desired to warm the exhaust gas purification device immediately after the operation of the internal combustion engine, the waste gate valve is opened. Thereby, the acceleration performance and the warm-up performance of the catalyst in the exhaust gas purification device are improved.

JP 2009-228486 A

  Some vehicles are provided with functions such as a normal driving mode, a fuel-saving driving mode that prioritizes suppression of fuel consumption over the normal driving mode, and a sports driving mode that prioritizes running performance over the normal driving mode. In such a vehicle, in order to respond to the acceleration request in the sports driving mode (solid line in FIG. 9), the throttle valve is opened in a short time (dashed line in FIG. 9), and the wastegate valve is opened for a short time. It is set so that it can be closed with. That is, the valve closing speed of the waste gate valve is set large.

  On the other hand, in the fuel-saving operation mode, when there is an acceleration request from the driver (solid line in FIG. 9), the throttle valve is set to slowly open (two-dot chain line in FIG. 9) with respect to the accelerator operation amount. ing. However, since the closing speed of the wastegate valve is the same as that in the sport driving mode, the wastegate valve is closed in a short time even in the fuel saving operation mode. Accordingly, since the boost pressure rises quickly with respect to the opening speed of the throttle valve (solid line in FIG. 10), it is large between the required minimum boost pressure satisfying the required torque (dotted line in FIG. 10). There is a difference. That is, there is a problem that fuel efficiency is reduced because useless supercharging pressure (the difference between the solid line and the dotted line in FIG. 10) is generated.

  In addition, although patent document 1 has the description of switching opening and closing of a wastegate valve, there is no description about the opening and closing speed of a wastegate valve.

  Therefore, the present invention is an invention made in view of the above-described problems of the prior art, and satisfies the required torque of the internal combustion engine when there is an acceleration request from the driver in a vehicle having a plurality of operation modes. An object of the present invention is to provide a supercharger control device for an internal combustion engine that can efficiently supply a supercharging pressure.

The supercharger control device for an internal combustion engine of the present invention that achieves the above object prioritizes running performance over the normal operation mode, the fuel saving operation mode that prioritizes suppression of fuel consumption over the normal operation mode, and the normal operation mode. A supercharger control device for an internal combustion engine equipped with a supercharger having a wastegate valve, which is equipped on a vehicle having a sports driving mode,
An operation mode selection means for selecting any one of the plurality of operation modes;
Throttle control means for opening the throttle valve in accordance with a predetermined throttle opening speed set in advance corresponding to the operation mode selected by the operation mode selection means;
Wastegate control means for controlling the valve closing amount of the wastegate valve in accordance with the predetermined throttle valve opening speed ,
An accelerator operation amount detection means for detecting the driver's accelerator operation amount;
An accelerator operation amount determination means for determining whether or not the accelerator operation amount detected by the accelerator operation amount detection means is equal to or greater than a predetermined value;
When the operation mode selected by the operation mode selection means is a fuel-saving operation mode and the accelerator operation amount determination means determines that the accelerator operation amount is greater than or equal to a predetermined value, the throttle control means While opening a valve according to the said throttle valve opening speed, the said waste gate control means controls the said waste gate valve in the valve closing direction according to the said throttle valve opening speed .

  According to the supercharger control device for an internal combustion engine of the present invention, the wastegate valve can be closed in accordance with the throttle valve opening speed in the selected operation mode. For this reason, the supercharging pressure can be gradually increased according to the opening degree of the throttle valve. That is, the boost pressure corresponding to the required torque of the internal combustion engine can be efficiently supplied. Thereby, useless supercharging pressure can be prevented from being generated, and fuel consumption can be improved.

Further, an accelerator operation amount detection means for detecting the driver's accelerator operation amount, and an accelerator operation amount determination means for determining whether or not the accelerator operation amount detected by the accelerator operation amount detection means is equal to or greater than a predetermined value. The throttle control means, when the operation mode selected by the operation mode selection means is a fuel-saving operation mode and the accelerator operation amount determination means determines that the accelerator operation amount is a predetermined value or more, The throttle valve is opened in accordance with the throttle valve opening speed, and the waste gate control means controls the waste gate valve in the valve closing direction in accordance with the throttle valve opening speed. When the accelerator operation amount detected by the operation amount detecting means is greater than a predetermined value, that is, driving There when it has the acceleration intention, it is possible to close the waste gate valve in accordance with the throttle opening speed. For this reason, the supercharging pressure can be increased according to the opening of the throttle valve. In this way, when the driver has an intention to accelerate in the fuel-saving driving mode, the wastegate valve is closed in accordance with the throttle valve opening speed, so that unnecessary supercharging pressure is prevented from being generated, The fuel consumption can be further improved.

  Further, when the driving mode selected by the driving mode selection means is a sports driving mode or a normal driving mode, the waste gate control means closes the waste gate valve, and the driver operates the throttle valve by an accelerator operation. Even if it opens, the closed state of the waste gate valve may be maintained until a predetermined rotational speed of the internal combustion engine or a predetermined load amount of the internal combustion engine set in the map is reached.

  As described above, when the wastegate valve is closed in the sport driving mode or the normal driving mode, the valve is not opened until the predetermined rotational speed of the internal combustion engine or the predetermined load amount of the internal combustion engine is reached. Therefore, if the driver operates the accelerator with the intention of accelerating in the sport driving mode or the normal driving mode, the wastegate valve is closed, so the turbine rotation speed immediately increases and supercharging starts. To do. As a result, the time lag from the acceleration request to the start of supercharging is almost eliminated, and the acceleration response can be improved.

  According to the present invention, in a vehicle having a plurality of operation modes, a supercharger for an internal combustion engine that can efficiently supply a supercharging pressure that satisfies the required torque of the internal combustion engine when there is an acceleration request from the driver. A control device can be provided.

It is a figure which shows the supercharger control apparatus of the internal combustion engine which concerns on embodiment of this invention. 1 is a block diagram of a supercharger control device for an internal combustion engine according to an embodiment of the present invention. It is a figure which shows the time-dependent change of the throttle opening which concerns on embodiment of this invention, and the opening of a throttle valve. It is a figure which shows the calculation method of accelerator opening increase amount (DELTA) APS which concerns on embodiment of this invention. It is a figure which shows the time-dependent change of the opening degree of the wastegate valve which concerns on embodiment of this invention. It is a flowchart which shows the supercharger control routine which concerns on embodiment of this invention. It is a figure which shows the time-dependent change of the request torque which concerns on embodiment of this invention. It is a figure which shows the time-dependent change of the supercharging pressure which concerns on embodiment of this invention. It is a figure which shows the time-dependent change of the opening degree of an accelerator and the opening degree of a throttle valve. It is a figure which shows the time-dependent change of supercharging pressure.

  Hereinafter, 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 only to specific examples unless otherwise specifically described. Only.

FIG. 1 is a diagram showing a supercharger control device for an internal combustion engine according to an embodiment of the present invention. FIG. 2 is a block diagram of the supercharger control device for the internal combustion engine according to the embodiment of the present invention.
As shown in FIGS. 1 and 2, an internal combustion engine 1 of a vehicle is provided in an internal combustion engine main body 11, an internal combustion engine main body 11, and a space surrounded by a piston 12, a cylinder head 13, and a cylinder 14. It has a combustion chamber 11a for burning fuel, an intake passage 2 for introducing air into the combustion chamber 11a, and an exhaust passage 3 for leading the combustion gas burned in the combustion chamber 11a to the outside of the internal combustion engine 1.

  The cylinder head 13 is provided with an injector 15. The injector 15 is disposed so that the tip side thereof faces the combustion chamber 11a, and fuel is directly injected from the injector 15 into the combustion chamber 11a.

  A fuel supply path 16 is provided between the injector 15 and a fuel tank (not shown), and a fuel pump 17 is provided on the fuel supply path 16.

The internal combustion engine 1 is provided with an EGR device 20. The EGR device 20 includes an EGR passage 21 (exhaust gas recirculation passage).
One end portion 21 a of the EGR passage 21 is connected to the intake passage 2 between the intake temperature sensor 18 and the throttle valve 19.
The other end 21 b of the EGR passage 21 is connected to the exhaust passage 3, and a part of the exhaust gas is introduced into the intake passage 2 through the EGR passage 21.

  One end portion 21 a of the EGR passage 21 is provided with an EGR valve 22 that opens and closes the EGR passage 21. An EGR cooler for cooling the exhaust gas flowing in the EGR passage 21 is provided upstream (exhaust side) of the EGR passage 22 in the EGR passage 21.

  The internal combustion engine 1 is provided with a supercharger 30. The supercharger 30 is disposed in the intake passage 2, is provided in the exhaust passage 3 with a compressor 31 that pressurizes the air sucked by the air cleaner 8, and exhausts exhaust gas in the exhaust passage 3. And a shaft 33 that connects the exhaust turbine 32 and the compressor 31 to each other.

The supercharger 30 rotates the exhaust turbine 32 with the exhaust gas discharged from the internal combustion engine 1. Then, the compressor 31 is driven by the rotational force of the exhaust turbine 32 to supercharge the air (intake air) in the intake passage 2. The supercharged air is supplied to the combustion chamber 11 a of each cylinder of the internal combustion engine 1.
An intercooler 4 for cooling the air supercharged by the compressor 31 is provided in the intake passage 2 downstream of the compressor 31 (downstream of the intake flow). Reference numeral 5 in the drawing indicates a catalyst provided downstream of the exhaust passage 32 in the exhaust passage 3.

The turbocharger 30 has one end connected to the exhaust passage 3 upstream of the exhaust turbine 32 and the other end connected to the exhaust passage 3 downstream of the exhaust turbine 32 to bypass the exhaust turbine 32. 34 is provided.
The bypass passage 34 is provided with a waste gate valve 35 and an electric motor 36 that controls the opening and closing of the waste gate valve 35.
By controlling the rotation amount and the rotation speed of the electric motor 36, the opening degree and the opening / closing speed of the waste gate valve 35 can be adjusted.

  And the supercharger control apparatus 6 which controls the supercharger 30 is provided with the operation mode selection switch 7 (equivalent to an operation mode selection means) and the accelerator sensor 9 (equivalent to an accelerator operation amount detection means). .

The driving mode selection switch 7 is provided in the driver's seat, and the driver is in the normal driving mode, the fuel-saving driving mode in which suppression of fuel consumption is given priority over the normal driving mode, and the sports driving mode in which driving performance is given priority over the normal driving mode Any one of the modes can be selected.
The operation mode selected by the operation mode selection switch 7 is output to the ECU 40.
In the present embodiment, three types of operation modes, the normal operation mode, the fuel-saving operation mode, and the sport operation mode, are used, but the present invention is not limited to this number. For example, you may have launch control operation mode etc. further.

  The accelerator sensor 9 detects the accelerator opening (accelerator operation amount) by the driver. And the detection result by the accelerator sensor 9 is output to ECU40.

  Further, the supercharger control device 6 includes throttle control means 43 that controls opening and closing of the throttle valve 19 and waste gate control means 41 that controls opening and closing of the waste gate valve 35.

  The throttle control means 43 and the wastegate control means 41 are provided in the ECU 40.

The throttle control means 43 calculates the throttle valve opening speed based on the detection result by the accelerator sensor 9 and the operation mode selected by the operation mode selection switch 7, and opens the throttle valve 19 according to the throttle valve opening speed.
As shown in FIG. 3, the throttle valve opening speed varies depending on the operation mode. For example, in the sports driving mode, as shown by the one-dot chain line in FIG. 3, the throttle valve 19 is opened at a speed equivalent to the acceleration request by the accelerator operation (solid line in FIG. 3). On the other hand, in the fuel saving operation mode, as indicated by a two-dot chain line in FIG. 3, the throttle valve 19 is slowly opened in response to the acceleration request by the accelerator operation.
The calculated opening speed of the throttle valve 19 is output to the wastegate control means 41.

The supercharger control device 6 further includes accelerator operation amount determination means 44 that determines whether or not the accelerator opening increase amount is equal to or greater than a predetermined value.
As shown in FIG. 4, the accelerator operation amount determination means 44 calculates an accelerator opening increase amount ΔAPS per unit time Δt based on the detection result of the accelerator sensor 9, and the accelerator opening increase amount ΔAPS is a predetermined value. It is determined whether it is above.
When it is determined that the accelerator opening increase amount ΔAPS is equal to or greater than a predetermined value, a closing signal for closing the waste gate valve 35 is generated. The created closing signal is output to the wastegate control means 41.

In addition, when the selected operation mode is the fuel-saving operation mode, the wastegate control unit 41 receives the closing signal output from the accelerator operation amount determination unit 44 and drives the electric motor 36 to control the throttle control unit 43. The waste gate valve 35 is closed in accordance with the valve opening speed of the throttle valve 19 output from.
Specifically, as the opening of the throttle valve 19 increases (see the two-dot chain line in FIG. 3), the opening of the waste gate valve 35 is set to gradually decrease as shown by the solid line in FIG. Has been. In addition, the dotted line in FIG. 5 has shown the change of the opening degree of the wastegate valve 35 at the time of sport driving mode.
In such a case, the wastegate control means 41 controls the rotation speed of the electric motor 36 so that the valve closing speed of the wastegate valve 35 coincides with the valve opening speed of the throttle valve 19.

  Various sensors such as an operation mode selection switch 7, an accelerator sensor 9, an intake air temperature sensor 18 that detects intake air temperature, an airflow sensor 25 that detects intake air amount, and an engine speed sensor (not shown) are provided at the input portion of the ECU 40. It is connected.

  Further, the wastegate valve 35, the throttle valve 19, the EGR valve 22, the fuel pump 17 of the internal combustion engine 1, and the like are connected to the output portion of the ECU 40.

  The ECU 40 further includes a CPU, ROM, RAM, backup RAM, and the like (not shown).

The ROM stores various control programs, maps that are referred to when the various control programs are executed, and the like.
The CPU executes various arithmetic processes based on various control programs and maps stored in the ROM.
The RAM is a memory that temporarily stores the calculation results of the CPU, data input from each sensor, and the like. The backup RAM stores, for example, data to be saved when the internal combustion engine 1 is stopped. It is a non-volatile memory.

  Next, control of the wastegate valve 35 in the present embodiment will be described.

The wastegate valve 35 is normally open or normally closed. Details of the normal open control and the normal close control will be described later.
When the driver selects the normal mode or the fuel saving operation mode, the normal open control is performed. On the other hand, when the driver selects the sport driving mode, the normal close control is performed.

In the normal open control, the valve is opened in the low rotation and low load range, and the waste gate valve 35 is controlled in the valve opening direction in the high rotation and high load range.
The normal open control map is used to control the waste gate valve 35 according to the engine speed and the engine load.
When acceleration (rotation and load increase) of the internal combustion engine 1 is started from a low rotation and low load range, the wastegate valve 35 is once controlled in the closing direction in the middle load range, and further enters the high load range and the boost pressure is predetermined. When the value is reached, the waste gate valve 35 is controlled in the opening direction.

On the other hand, the normal close control is a control for closing the wastegate valve 35 in a low rotation and low load range including idling.
The normal close control map is used to control, and the normal close control map defines the open / close state of the wastegate valve 35 according to the engine speed and the engine load, similarly to the normal open control map.
In the case of normal close control, the wastegate valve 35 is closed in a low rotation and low load range such as idling.
When acceleration (rotation and load increase) of the internal combustion engine 1 is started from a low rotation and low load range, the closed state of the waste gate valve 35 is maintained until the high load range is reached, and the supercharging pressure is entered into the high load range. When reaching the value, the waste gate valve 35 is controlled in the valve opening direction.

By the way, in a vehicle provided with a plurality of operation modes, the wastegate valve 35 is generally set to be closed in a short time in order to cope with an acceleration response in the sport operation mode. That is, the valve closing speed of the waste gate valve 35 is set large.
On the other hand, in the fuel saving operation mode, the throttle valve 19 is set to open slowly with respect to the accelerator opening increase amount ΔAPS even when the driver requests acceleration. That is, the opening speed of the throttle valve 19 is set small. However, since the wastegate valve 35 is closed in a short time even in the fuel-saving operation mode, the boost pressure rises too early with respect to the opening speed of the throttle valve 19 and wasteful boost pressure is generated. Resulting in. For this reason, fuel consumption will deteriorate.

Therefore, in the present invention, when there is an acceleration request from the driver in the fuel saving operation mode, the valve closing speed of the waste gate valve 35 is controlled so as to match the valve opening speed of the throttle valve 19.
On the other hand, in the sport driving mode or the normal driving mode, the waste gate valve 35 is closed, and even if there is an acceleration request from the driver, the waste gate is reached until the engine speed and engine load set in the map are reached. The valve 35 is not opened.

  Hereinafter, the control method of the wastegate valve 35 will be described with reference to the flowchart of FIG. FIG. 6 is a flowchart showing a supercharger control routine for controlling the wastegate valve 35.

As shown in FIG. 6, first, the driver operates the operation mode selection switch 7 to select an operation mode (step S1).
The selected operation mode is output to the ECU 40.

Next, the wastegate control means 41 determines whether or not the selected operation mode is a fuel saving operation mode (step S2).
When it is determined that the operation mode is the fuel-saving operation mode (step S2: YES), the wastegate control unit 41 drives the electric motor 36 to open the wastegate valve 35 and performs the normal open control (step S2). S3).

Next, the accelerator opening is detected by the accelerator sensor 9 (step S4).
Then, based on the detection result detected by the accelerator sensor 9, the wastegate control means 41 calculates the accelerator opening increase amount ΔAPS.

Subsequently, the wastegate control means 41 determines whether or not the accelerator opening increase amount ΔAPS is equal to or larger than a predetermined value At determined in advance by design or the like (step S5).
When the wastegate control means 41 determines that the accelerator opening increase amount ΔAPS is equal to or greater than the predetermined value At (step 5: YES), the wastegate valve 35 closes the wastegate valve 35 so as to match the opening speed of the throttle valve 19. The waste gate valve 35 is controlled in the valve closing direction while controlling the valve speed (step S6).

  On the other hand, the wastegate control means 41 implements step S4 again, when it determines with the accelerator opening increase amount (DELTA) APS being less than predetermined value At (step 5: NO).

  By the way, if it is determined in step S2 that the operation mode is not the fuel-saving operation mode (step S2: NO), the wastegate valve 35 is closed and normal close control is performed (step S2). S7).

  According to the supercharger control device 6 of the internal combustion engine 1 described above, since the accelerator sensor 9 is provided, the driver's intention to accelerate can be grasped. When the accelerator opening increase amount ΔAPS is equal to or larger than the predetermined value At, the driver is considered to have an intention to accelerate. Therefore, the throttle valve 19 is opened according to a predetermined throttle opening speed corresponding to the operation mode. Thus, it can be accelerated as the driver intends.

  In the fuel saving operation mode, when the accelerator operation amount is equal to or greater than the predetermined value At, the wastegate valve 35 can be closed in accordance with the opening speed of the throttle valve 19. For this reason, the supercharging pressure can be gradually increased in accordance with the opening degree of the throttle valve 19. That is, the supercharging pressure (see FIG. 8) that can satisfy the required torque (see FIG. 7) of the internal combustion engine 1 can be efficiently supplied. Thereby, it is possible to prevent unnecessary supercharging pressure from being generated, improve fuel efficiency, and improve drivability.

  Further, when the waste gate valve 35 is closed in the sport driving mode or the normal driving mode, the valve is not opened until the predetermined rotational speed of the internal combustion engine or the predetermined load amount of the internal combustion engine is reached. Therefore, when the driver performs an accelerator operation with the intention of accelerating in the sport driving mode or the normal driving mode, the wastegate valve 35 is closed, so that the turbine rotation speed immediately increases and supercharging is performed. Start. As a result, the time lag from the acceleration request to the start of supercharging is almost eliminated, and the acceleration response can be improved.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Intake passage 3 Exhaust passage 4 Intercooler 5 Catalyst 6 Supercharger control device 7 Operation mode selection switch 8 Air cleaner 9 Accelerator sensor 11 Internal combustion engine body 11a Combustion chamber 12 Piston 13 Cylinder head 14 Cylinder 15 Injector 16 Fuel supply passage Reference Signs List 17 Fuel Pump 18 Intake Air Temperature Sensor 19 Throttle Valve 20 EGR Device 21 EGR Passage 21a One End 21b Other End 22 EGR Valve 25 Airflow Sensor 30 Supercharger 31 Compressor 32 Exhaust Turbine 33 Shaft 34 Bypass Passage 35 Wastegate Valve 36 Electric Motor 40 ECU
41 Wastegate control means 43 Throttle control means 44 Accelerator operation amount determination means

Claims (2)

A turbocharger equipped with a normal driving mode, a fuel-saving driving mode that prioritizes suppression of fuel consumption over the normal driving mode, and a sports driving mode that prioritizes driving performance over the normal driving mode, and having a wastegate valve A supercharger control device for an internal combustion engine comprising:
An operation mode selection means for selecting any one of the plurality of operation modes;
Throttle control means for opening the throttle valve in accordance with a predetermined throttle opening speed set in advance corresponding to the operation mode selected by the operation mode selection means;
Wastegate control means for controlling the valve closing amount of the wastegate valve in accordance with the predetermined throttle valve opening speed ,
An accelerator operation amount detection means for detecting the driver's accelerator operation amount;
An accelerator operation amount determination means for determining whether or not the accelerator operation amount detected by the accelerator operation amount detection means is equal to or greater than a predetermined value;
When the operation mode selected by the operation mode selection means is a fuel-saving operation mode and the accelerator operation amount determination means determines that the accelerator operation amount is greater than or equal to a predetermined value, the throttle control means A supercharger control for an internal combustion engine , wherein the wastegate control means controls the wastegate valve in a valve closing direction in accordance with the throttle valve opening speed while opening a valve according to the throttle valve opening speed. apparatus. When the driving mode selected by the driving mode selection means is a sports driving mode or a normal driving mode, the waste gate control means closes the waste gate valve, and the driver opens the throttle valve by an accelerator operation. 2. The internal combustion engine according to claim 1 , wherein the closed state of the waste gate valve is maintained until a predetermined rotational speed of the internal combustion engine or a predetermined load amount of the internal combustion engine set in a map is reached. Engine supercharger control device.

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