JP2007211630A - Control device for internal combustion engine with electric supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of an internal combustion engine with an electric supercharger in which the response of the supercharger is secured while suppressing the consumption of electric power. <P>SOLUTION: When the operating condition of the engine 1 is determined to be stationary by a control map M1, a bypass valve 32 is controlled to the opening based on the control map M2. Since the intake air amount of a predetermined amount or more is fed into a compressor, the rotational speed of the compressor is increased to a predetermined rotational speed or higher, and the supply of the electric power to the motor 20 is stopped. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine including a supercharger driven by an electric motor.

For the purpose of improving the output of an internal combustion engine (hereinafter also referred to as the engine), a turbocharger that drives a turbine by the exhaust flow of the engine and rotates the turbocharger to supercharge intake air, or a turbocharger that utilizes engine rotation A supercharger and the like that rotate the engine to supercharge intake air has been put into practical use.
In recent years, an electric supercharger that drives a supercharger with an electric motor has been proposed.

For example, a supercharger that is driven by an electric motor is provided, and a bypass passage that bypasses the supercharger and a bypass valve that adjusts the opening of the bypass passage are provided. A configuration is known in which the turbocharger rotation speed is controlled by an electric motor so that the target boost pressure is obtained at the bypass valve opening at this time (see Patent Document 1).
JP 2001-280145 A

However, in general, an electric motor used to drive a supercharger consumes a relatively large amount of electric power, and the technique disclosed in Patent Document 1 always consumes electric power even during steady operation. There is a problem that increases.
Therefore, it is possible to stop the power supply to the motor during steady operation, but if the motor is stopped and the turbocharger stops completely, the responsiveness when rotating the turbocharger again decreases. There is a problem of end up.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide an internal combustion engine with an electric supercharger capable of ensuring responsiveness of the supercharger while suppressing power consumption. It is to provide an engine control device.

  In order to achieve the above object, in the control device for an internal combustion engine with an electric supercharger according to claim 1, a supercharger that is provided in an intake passage of the internal combustion engine and supercharges intake air, and is connected to the supercharger. An electric motor driven by electric power to rotate the supercharger, a supercharger control means for controlling the operation of the supercharger by controlling power supply to the electric motor, and the supercharger in the intake passage. A bypass passage formed around the feeder, a bypass valve provided in the bypass passage and capable of adjusting a bypass flow rate in the bypass passage, and a bypass valve control means for controlling an opening degree of the bypass valve; Operating state detecting means for detecting the operating state of the internal combustion engine, and when the predetermined low load operating state of the internal combustion engine is detected by the operating state detecting means, the supercharging by the bypass valve control means. The opening of the bypass valve is controlled to be throttled so that an intake air flow rate of a predetermined amount or more such that the rotational speed of the motor is equal to or higher than a predetermined rotational speed, and the electric motor is controlled by the supercharger control means. The power supply to is stopped.

That is, in an internal combustion engine equipped with a supercharger driven by an electric motor, when the internal combustion engine is in a predetermined low load operation state, the opening degree of the bypass valve is controlled to be throttled, and an intake air flow rate greater than a predetermined amount is sent to the supercharger. Thus, the rotational speed of the supercharger is set to a predetermined rotational speed or more, and the power supply to the electric motor is stopped.
According to a control device for an internal combustion engine with an electric supercharger according to a second aspect of the present invention, in the first aspect, the operating state detection means includes an intake pressure detection means for detecting an intake pressure of the internal combustion engine, and the intake pressure detection means When the detected intake pressure is less than a first predetermined value, the internal combustion engine is determined to be in a predetermined low load operation state.

That is, the operation state detection means includes intake pressure detection means, and when the intake pressure detected by the intake pressure detection means is less than the first predetermined value, it is determined that the predetermined low load operation state.
According to a third aspect of the present invention, there is provided a control device for an internal combustion engine with an electric supercharger according to the second aspect, wherein the operating state detecting means is configured such that the intake pressure detected by the intake pressure detecting means is greater than or equal to the first predetermined value. When the operating state of the internal combustion engine is in a natural intake operation state that does not require a supercharging operation, and when the natural intake operation state is detected by the operation state detection means, the bypass valve control Means for controlling the opening degree of the bypass valve to be fully open, and the supercharger control means for controlling power supply to the electric motor so as to maintain the rotation speed of the supercharger at or above the predetermined rotation speed. It is characterized by.

In other words, when the intake pressure is equal to or higher than the first predetermined value and lower than the second predetermined value, it is determined as a normal natural intake operation state, the opening degree of the bypass valve is fully opened, and the rotation speed of the supercharger is controlled by the electric motor. Maintain above the specified rotational speed.
According to a fourth aspect of the present invention, there is provided a control device for an internal combustion engine with an electric supercharger, wherein the operating state detecting means is configured such that the intake pressure detected by the intake pressure detecting means is greater than or equal to the second predetermined value. When the operation state of the internal combustion engine is in a supercharging operation state that requires a supercharging operation, and when the supercharging operation state is detected by the operation state detecting means, the bypass valve control Means for controlling the opening degree of the bypass valve to be fully closed, and the supercharger control means controls the power supply to the electric motor so as to perform supercharging by the supercharger.

That is, when the intake pressure is greater than or equal to the second predetermined value and less than the third predetermined value, it is determined that the engine is in a supercharging operation state, the bypass valve opening is fully closed, and supercharging is performed by the supercharger.
In the control device for an internal combustion engine with an electric supercharger according to claim 5, in claim 4, when the intake pressure detected by the intake pressure detection means is not less than the third predetermined value, the operating state detection means is When it is determined that the operating state of the internal combustion engine has reached a supercharging limit state, and the supercharging limit state is detected by the operating state detection means, the bypass valve control means increases the opening of the bypass valve. And the power supply to the electric motor is controlled by the supercharger control means so as to reduce the rotation speed of the supercharger.

  That is, when the intake pressure is equal to or higher than the third predetermined value, it is determined that the turbocharge limit state is set, the bypass valve is opened, and the rotational speed of the supercharger is decreased.

  According to the control device for an internal combustion engine with an electric supercharger according to claim 1 of the present invention using the above means, the power consumption is reduced by stopping the power supply to the electric motor when the internal combustion engine is in a predetermined low load operation state. In addition to being able to suppress, the opening degree of the bypass valve is controlled and the intake air flow rate of a predetermined amount or more is sent to the supercharger so that the rotation speed of the supercharger is equal to or higher than the predetermined rotation speed. Responsiveness can be ensured.

According to the control device for an internal combustion engine with an electric supercharger according to claim 2, the operating pressure detecting means includes an intake pressure detecting means for detecting the intake pressure of the internal combustion engine, and the intake pressure detected by the intake pressure detecting means is By determining the predetermined low-load operation state when it is less than the first predetermined value, the supercharger control and the bypass valve control can be easily performed.
According to the control device for an internal combustion engine with an electric supercharger according to claim 3, when it is determined that the intake air pressure is in the natural intake operation state of the first predetermined value or more and less than the second predetermined value, the bypass valve is fully opened. Pumping loss can be reduced and fuel efficiency can be improved, and the responsiveness of the supercharger can be ensured by maintaining the rotational speed of the supercharger at a predetermined rotational speed or higher by the electric motor.

According to the control apparatus for an internal combustion engine with an electric supercharger according to claim 4, when it is determined that the intake pressure is in the supercharging operation state of the second predetermined value or more and less than the third predetermined value, the bypass valve is fully closed, By sending this intake air to the supercharger, it is possible to perform supercharging with excellent responsiveness.
According to the control device for an internal combustion engine with an electric supercharger according to claim 5, when the intake pressure is determined to be in a supercharging limit state of a third predetermined value or more, the rotational speed of the supercharger is reduced by the electric motor. In addition, by increasing the opening degree of the bypass valve, a double safety mechanism is achieved by reducing the supercharging pressure, and the supercharging pressure can be reliably returned to less than the supercharging limit value at an early stage.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Referring to FIG. 1, there is shown a schematic configuration diagram of a control device for an internal combustion engine with an electric supercharger according to the present invention.
As shown in FIG. 1, the intake passage 2 of the engine 1 is provided with an air cleaner 4 at the intake upstream end, and a compressor 10 (supercharger) is provided downstream of the air cleaner 4 with respect to the intake.

The compressor 10 is configured such that a compressor impeller 14 is rotatably supported in a compressor housing 12 formed in communication with the intake passage 2.
The rotation shaft of the compressor impeller 14 is connected to an electric motor 20 (electric motor).
The motor 20 is electrically connected to a battery (not shown) mounted on the vehicle, and has a function of driving and rotating the compressor impeller 14 when electric power is supplied from the battery.

The compressor 10 has a function of supercharging intake air as the compressor impeller 14 rotates.
Also, a butterfly throttle valve 22 is provided on the intake passage 2 downstream of the compressor 10 with respect to the intake air. The throttle valve 22 is opened and closed by an actuator 24 and has a function of adjusting the intake air amount by changing the passage area of the intake passage 2.

Further, an intake pressure sensor 26 for detecting the intake pressure is provided downstream of the throttle valve 22.
The intake passage 2 is formed with a bypass passage 30 that connects a portion between the air cleaner 4 and the compressor 10 and a portion between the compressor 10 and the throttle valve 22 so as to bypass the compressor 10.

The bypass passage 30 is provided with a butterfly-type bypass valve 32. The bypass valve 32 has a function of adjusting the bypass flow rate through the bypass passage 30 by opening and closing by the actuator 34 and changing the passage area of the bypass passage 30.
The engine 1 is provided with a rotation speed sensor 40 that detects the engine rotation speed.

Further, an accelerator sensor 42 that detects the amount of operation of the accelerator is provided in a vehicle on which the engine 1 is mounted.
Various devices and various sensors such as the actuators 24 and 34 of the motor 20, the throttle valve 22 and the bypass valve 32, the intake pressure sensor 26, the rotation speed sensor 40, and the accelerator sensor 42 are mounted on an ECU (electronic device). The ECU 50 is electrically connected to a control unit 50, and the ECU 50 controls the operation of various devices based on information from various sensors.

For example, the ECU 50 supplies power to the motor 20 in accordance with the accelerator operation amount detected by the accelerator sensor 42, the intake pressure detected by the intake pressure sensor 26, the engine speed detected by the rotational speed sensor 40, and the like. It has a function to control and control the operation of the compressor 10 (supercharger control means).
The ECU 50 also has a function of controlling the opening degree of the bypass valve 32 based on a preset control map (bypass valve control means).

The operation of the control apparatus for an internal combustion engine with an electric supercharger according to the present invention configured as described above will be described below.
Referring to FIG. 2, there is shown a control map M1 used for bypass valve control of the control device for an internal combustion engine with an electric supercharger according to the present invention. With reference to FIG. 3, the internal combustion engine with an electric supercharger according to the present invention. A control routine of the bypass valve 32 of the engine control device is shown in a flowchart.

The control map M1 in FIG. 2 shows the operation region of the bypass valve 32 set based on the intake pressure and the engine speed, and will be described below with reference to the control map M1 along the flowchart in FIG. .
First, in step S1, the ECU 50 reads the intake pressure detected by the intake pressure sensor 26 and the engine rotational speed detected by the rotational speed sensor 40.

  In subsequent step S2, it is determined whether or not the engine 1 is in a steady operation state (a predetermined low load operation state). This determination is performed by determining whether or not the intake pressure is less than the first predetermined value from the control map M1 of FIG. The first predetermined value is set to a boundary value between the natural intake operation and the steady operation, and a region less than the first predetermined value in FIG. 2 indicates a steady operation state.

If the determination result is true (Yes), the process proceeds to step S3.
In step S3, the degree of opening of the bypass valve 32 is controlled through the actuator 34 based on a control map M2 (not shown) set separately from the control map M1 in FIG. The control map M2 is an opening degree at which an intake air flow rate of a predetermined amount or more at which the rotation speed of the compressor 10 is equal to or higher than a predetermined rotation speed (for example, 5000 rpm) that is an idle rotation speed is sent to the compressor 10 according to the operating state of the engine 1. Is set to That is, by restricting the bypass valve 32 to the opening based on the control map M2, the bypass flow rate through the bypass passage 30 is limited, and the intake flow rate through the intake passage 2 is increased by that amount, so that the intake flow rate equal to or greater than a predetermined amount is compressed. Send to 10. Thus, when the intake air flow rate of a predetermined amount or more is sent to the compressor 10, the compressor 10 rotates at a predetermined rotation speed or more.

In the subsequent step S4, the power supply to the motor 20 is stopped and the routine is exited.
As described above, when it is determined that the steady operation is performed in the control map M1, the bypass valve 32 is throttled to the opening based on the control map M2, the bypass flow rate is limited, and the intake air amount greater than a predetermined amount is reduced to the compressor 10. , The rotation speed of the compressor 32 can be maintained at a predetermined rotation speed or higher by the intake air flow while the power supply to the motor 20 is stopped. During steady operation where the intake pressure is less than the first predetermined value, the pumping loss does not increase significantly even if the bypass valve 32 is throttled because the load is small.

Thereby, the responsiveness of supercharging by the compressor 10 can be ensured while suppressing power consumption.
On the other hand, if the determination result is false (No) in step S2, the process proceeds to step S5.
In step S5, it is determined whether or not the operating state of the engine 1 is a natural intake operation, that is, whether or not supercharging is performed. This determination is performed by determining whether or not the intake pressure is less than the second predetermined value from the control map M1 of FIG. The second predetermined value is set to a boundary value between the natural intake operation and the supercharging operation. In FIG. 2, a region less than the second predetermined value is a natural intake operation state, and a region greater than the second predetermined value is an excessive value. The feed operation state is shown.

If the determination result is true (Yes), that is, if the intake air pressure is a natural intake operation that is greater than or equal to the first predetermined value and less than the second predetermined value, the process proceeds to step S6.
In step S6, the actuator 34 is controlled so that the opening degree of the bypass valve 32 is fully opened.
In step S7, the motor 20 is supplied with a predetermined power (for example, 1A), and the idling operation is performed in which the rotation speed of the compressor 10 is maintained at the predetermined rotation speed (5000 rpm), and the routine is exited.

In this manner, when the natural intake operation state is not a steady operation but is in a middle load, the bypass valve 32 is fully opened, thereby reducing the pumping loss of intake air and reducing the fuel consumption. And the responsiveness at the time of supercharging can be ensured by supplying a predetermined amount of electric power to the motor 20 and maintaining the rotational speed of the compressor 10 at the predetermined rotational speed.
Furthermore, if the determination result is false (No) in step S5, that is, if it is in the supercharging operation state, the process proceeds to step S8.

  In step S8, it is determined whether or not the intake pressure is within a supercharging limit pressure, that is, whether or not the intake pressure is in a supercharging state where the intake pressure is higher than necessary. This determination is performed by determining whether or not the intake pressure is less than the third predetermined value from the control map M1 of FIG. The third predetermined value is set to the supercharging limit pressure, and the region that is equal to or greater than the third predetermined value in FIG. 2 indicates the supercharging region.

When the determination result is true (Yes), that is, when the normal supercharging operation is within the supercharging limit pressure, the process proceeds to step S10.
In step S10, the actuator 34 is controlled so that the opening degree of the bypass valve 32 is fully closed.
And in step S11, normal supercharging control according to an accelerator opening degree, an engine speed, etc. is performed.

As described above, during normal supercharging operation in which the intake pressure is within the supercharging limit pressure, the bypass valve 32 is fully closed, so that all the intake air is sent to the compressor 10 and the response when the compressor 10 is supercharged. Sex can be secured.
On the other hand, if the determination result in step S8 is false (No), that is, if the engine is in the supercharging operation state, the process proceeds to step S12.

In step S12, the opening degree of the bypass valve 32 is increased by a certain amount.
In step S13, the motor 20 is controlled to decrease the rotational speed of the compressor 10, and the routine is exited.
When the intake pressure is in a supercharging state that is equal to or higher than the supercharging limit pressure, the motor 20 reduces the rotational speed of the compressor 10 and increases the opening of the bypass valve 32 to increase the supercharging. By reducing the pressure, a double safety mechanism is formed by the motor 20 and the bypass valve 32, and the normal intake pressure can be reliably restored at an early stage.

Although the description of the embodiment of the control device for the internal combustion engine with the electric supercharger according to the present invention has been completed, the embodiment is not limited to the above embodiment.
For example, in the above embodiment, the bypass valve 32 is a butterfly valve, but may be a valve having another configuration as long as the passage area in the bypass passage 30 can be varied.

Moreover, in the said embodiment, although it is the structure which rotates the compressor 10 only with the motor 20, this may be the structure which used the exhaust turbo and the motor together, for example.
Moreover, in the said embodiment, although the control map M1 shown in FIG. 2 is set based on the intake pressure, you may set this based on other factors, such as volume efficiency and an accelerator opening.
In the above embodiment, the opening degree of the bypass valve 32 is controlled based on the control map M2 during steady operation, but the control map M2 is not necessarily set. For example, a predetermined opening degree is set in advance. During the steady operation, the opening degree of the bypass valve 32 may be controlled to the predetermined opening degree.

It is a schematic block diagram of the control apparatus of the internal combustion engine with an electric supercharger according to the present invention. It is the control map M1 used for control apparatus bypass valve control of the internal combustion engine with an electric supercharger concerning the present invention. The bypass valve control routine of the control apparatus for the internal combustion engine with the electric supercharger according to the present invention is a flowchart.

Explanation of symbols

1 engine (internal combustion engine)
2 Intake passage 10 Compressor (supercharger)
20 Motor (electric motor)
DESCRIPTION OF SYMBOLS 22 Throttle valve 24, 34 Actuator 26 Intake pressure sensor 30 Bypass passage 32 Bypass valve 40 Rotational speed sensor 42 Acceleration sensor 50 ECU (supercharger control means, bypass valve control means)

Claims (5)

A supercharger that is provided in an intake passage of the internal combustion engine and supercharges intake air;
An electric motor connected to the supercharger and driven by electric power to rotate the supercharger;
Supercharger control means for controlling the operation of the supercharger by controlling power supply to the motor;
A bypass passage formed around the supercharger in the intake passage;
A bypass valve provided in the bypass passage and capable of adjusting a bypass flow rate in the bypass passage;
Bypass valve control means for controlling the opening of the bypass valve;
Operating state detecting means for detecting the operating state of the internal combustion engine,
When the predetermined low load operating state of the internal combustion engine is detected by the operating state detecting means,
The bypass valve control means throttles and controls the degree of opening of the bypass valve so that an intake air flow rate of a predetermined amount or more such that the rotational speed of the supercharger is equal to or higher than a predetermined rotational speed is sent to the supercharger. ,
A control device for an internal combustion engine with an electric supercharger, wherein the supercharger control means stops power supply to the electric motor. The operating state detecting means includes an intake pressure detecting means for detecting an intake pressure of the internal combustion engine,
2. The internal combustion engine with an electric supercharger according to claim 1, wherein when the intake pressure detected by the intake pressure detection means is less than a first predetermined value, the internal combustion engine is determined to be in a predetermined low load operation state. Engine control device. When the intake pressure detected by the intake pressure detection means is greater than or equal to the first predetermined value and less than a second predetermined value, the operation state detection means is a natural intake that does not require a supercharging operation. Determine that you are in the driving state,
When the natural intake operation state is detected by the operation state detection means,
The bypass valve control means controls the opening degree of the bypass valve to be fully open,
3. The internal combustion engine with an electric supercharger according to claim 2, wherein the supercharger control means controls the power supply to the electric motor so as to maintain the rotational speed of the supercharger at or above the predetermined rotational speed. Engine control device. When the intake pressure detected by the intake pressure detection means is greater than or equal to the second predetermined value and less than a third predetermined value, the operating state detecting means is a turbocharger that requires a supercharging operation. Determine that you are in the driving state,
When the supercharging operation state is detected by the operation state detection means,
The bypass valve control means controls the opening degree of the bypass valve to be fully closed,
4. The control device for an internal combustion engine with an electric supercharger according to claim 3, wherein the supercharger control means controls power supply to the electric motor so as to perform supercharging by the supercharger. The operating state detecting means determines that the operating state of the internal combustion engine has reached a supercharging limit state when the intake pressure detected by the intake pressure detecting means is not less than the third predetermined value;
When the supercharging limit state is detected by the operating state detection means,
Control by the bypass valve control means to increase the opening of the bypass valve,
5. The control device for an internal combustion engine with an electric supercharger according to claim 4, wherein the supercharger control means controls power supply to the electric motor so as to reduce a rotation speed of the supercharger.

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