JP2020176588A - Control device for engine - Google Patents

Abstract

To improve delay of response to an acceleration request during introduction of exhaust recirculation gas.SOLUTION: A control device for an engine includes: an intake passage 1; an exhaust passage 2; an exhaust gas recirculation device 13 introducing a part of exhaust gas to intake air through an exhaust gas recirculation passage 13a connecting the intake passage 1 and the exhaust passage 2 as exhaust recirculation gas; a rotating body 15 provided in a merged part 13b with the intake passage 1 of the exhaust gas recirculation passage 13a; and a drive source 17 applying driving force to the rotating body 15 to rotate the rotating body 15. The exhaust recirculation gas in a retention space L is introduced into the intake passage 1 due to negative pressure generated around the rotating body 15 through the rotation of the rotating body 15.SELECTED DRAWING: Figure 1

Description

The present invention relates to an engine control device.

In general, an exhaust gas recirculation device that introduces a part of the exhaust gas into the intake air as an exhaust return gas is often provided between the exhaust passage and the intake passage of the engine. For example, the exhaust gas recirculation device of the engine of Patent Document 1 includes an exhaust gas recirculation passage that communicates between the exhaust passage and the intake passage, an exhaust recirculation valve provided in the exhaust recirculation passage, and an exhaust recirculation passage of the intake passage. It is equipped with a throttle valve provided on the upstream side of the confluence of. The throttle valve is a butterfly valve type valve body, and the cross-sectional area of the flow path of the intake passage can be increased or decreased depending on the opening degree of the valve body. By reducing the opening degree of the throttle valve to create a negative pressure in the intake passage and opening the exhaust recirculation valve, an appropriate amount of exhaust recirculation gas is introduced into the intake air. By introducing this exhaust recirculation gas into the intake air, fuel efficiency can be improved and knocking can be suppressed (see, for example, Patent Document 1).

By the way, the required load on the engine is determined based on the accelerator opening degree by the driver. According to this required load, the target exhaust gas return gas ratio, which is the target of the ratio of the exhaust gas return gas to the entire intake air, is determined. Generally, in the medium load region and the high load region, the larger the required load, the lower the exhaust gas return gas ratio is set. The opening and closing of the throttle valve, the exhaust recirculation valve, etc. is controlled according to the determined value of the target exhaust recirculation gas rate, and the amount of the exhaust recirculation gas introduced into the intake air is adjusted.

During operation, for example, when there is a request for full-open acceleration, the exhaust gas rate is changed from the exhaust gas rate according to the operating state at that time to the target exhaust gas rate corresponding to full-open driving. Is required. Therefore, the throttle valve, the exhaust recirculation valve, and the like are controlled to adjust the exhaust recirculation gas ratio in order to meet the demand.

Japanese Unexamined Patent Publication No. 2012-052481

By the way, when the driver requests acceleration during operation, it is required to increase the amount of intake air introduced into the engine. However, in the operation state in the previous stage, when the opening degree of the throttle valve is small in order to introduce the exhaust recirculation gas into the intake air, the flow of fresh air from the upstream side is hindered. That is, at the time of the request for acceleration, the amount of intake air in the intake passage is decreasing. In such a situation, even if the throttle valve far from the combustion chamber is opened in response to the driver's acceleration request, it takes time to increase the amount of intake air introduced into the combustion chamber. Therefore, there is a problem that a response delay (time lag) is likely to occur in response to the driver's acceleration request, and a comfortable driving feeling is impaired.

Therefore, an object of the present invention is to improve the response delay to the acceleration request during the introduction of the exhaust gas.

In order to solve the above problems, the present invention presents an exhaust gas through an intake passage for introducing intake gas into a combustion chamber, an exhaust passage for sending exhaust gas from the combustion chamber, and an exhaust return passage connecting the intake passage and the exhaust passage. An exhaust gas recirculation device that partially introduces the exhaust gas into the intake gas, a rotating body provided at the confluence of the exhaust gas recirculation passage with the intake passage, and a rotating body driven by the rotating body to rotate the rotating body. A drive source for applying a force is provided, and an exhaust gas recirculated gas in the exhaust recirculation passage is introduced into the intake passage by a negative pressure generated around the rotating body due to the rotation of the rotating body.

Further, the rotating body is provided with a tubular portion having a retention space for exhaust / return gas inside the peripheral wall portion, the exhaust / return passage is connected to the retention space, and the retention space and the intake passage form the peripheral wall portion. It is possible to adopt a configuration in which the rotating body rotates around the tubular axis of the tubular portion by communicating with the guide hole through which the rotating body is formed.

Further, the rotating body adopts a configuration in which the tubular portion is arranged so that the axial direction of the tubular portion is along the flow direction of the intake passage, and the exhaust / reflux passage is connected to the upstream end portion of the tubular portion. can do.

Further, the guide hole is set at a position where a rotational force in the same direction as the rotation direction of the rotating body by the drive source is applied by the flow of the exhaust gas returning gas introduced from the retention space to the intake passage. Can be adopted.

Further, a means for determining the exhaust gas return gas rate, which is a target of the exhaust gas return gas rate, which is the ratio of the exhaust gas return gas to the intake air, according to the load of the engine, and an actual exhaust gas in the intake air. The exhaust gas recirculation device control means for controlling the actual exhaust gas recirculation gas rate, which is the recirculation gas rate, to approach the target exhaust gas recirculation gas rate according to the load of the engine at that time, and the drive source is a motor. The exhaust gas recirculation device control means can adopt a configuration in which the rotation speed of the motor is controlled based on the actual exhaust gas recirculation gas rate and the target exhaust gas recirculation gas rate.

In the present invention, a rotating body is provided at a confluence with an intake passage of an exhaust recirculation passage, and a negative pressure is generated around the rotating body by the rotation of the rotating body, so that the exhaust recirculation gas in the exhaust recirculation passage is smoothly taken in. Can be introduced to. As a result, the amount of throttle of the intake air in the intake passage during the introduction of the exhaust gas is suppressed, so that the response delay to the subsequent acceleration request can be improved.

It is a block diagram of the engine which shows one Embodiment of this invention. It is an enlarged view of the main part of FIG. The details of the rotating body are shown, (a) is a partial cross-sectional view, and (b) is a front view.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall view showing a control device for the engine E of the present invention.

The engine E includes an intake passage 1 for introducing intake air through the combustion chamber 10 of a cylinder accommodating a piston P, and an exhaust passage 2 for drawing out exhaust gas from the combustion chamber 10. The intake port 11 which is the connection part of the intake passage 1 to the combustion chamber 10 and the exhaust port 12 which is the connection part of the exhaust passage 2 to the combustion chamber 10 are opened and closed by the intake valve 1a and the exhaust valve 2a, respectively. It has become. Further, the combustion chamber 10 and the intake port 11 are provided with a fuel injection device 8 for injecting fuel into the intake air. In this embodiment, a direct injection valve type fuel injection device 8 facing the combustion chamber 10 is provided.

The intake passage 1 includes a throttle valve 9 that adjusts the flow path area of the intake passage 1 from the intake port 11 to the upstream side, an intake cooling device (intercooler) 6 that cools the intake air flowing through the intake passage 1, and a turbocharger. The compressor 23 of 21 and the air cleaner 18 and the like are provided. Further, the intake passage 1 is provided with an air flow sensor 31 that detects the amount of intake air.

The exhaust passage 2 is provided with a turbine 22 of a turbocharger 21, an exhaust purification unit 19 for removing harmful substances in exhaust gas, and a muffler 20 toward the downstream side from the exhaust port 12. Further, the exhaust passage 2 is provided with an exhaust temperature sensor, an air-fuel ratio sensor, and the like on the downstream side of the exhaust purification unit 19.

An exhaust gas recirculation device 13 is provided between the intake passage 1 and the exhaust passage 2 to connect the intake passage 1 and the exhaust passage 2 and introduce a part of the exhaust gas into the intake air as an exhaust return gas.

The exhaust gas recirculation device 13 includes an exhaust gas recirculation passage 13a connecting between the exhaust purification unit 19 of the exhaust passage 2 and the silencer 20 and the upstream portion of the compressor 23 of the intake passage 1 and the exhaust recirculation passage thereof. An exhaust gas return gas cooler provided in the middle of the exhaust gas return gas 13a for cooling the exhaust gas return gas, and an exhaust return valve 14 for opening and closing the flow path of the exhaust gas return passage 13a are provided.

As shown in FIGS. 1 and 2, the exhaust return passage 13a penetrates the pipe wall of the intake passage 1 and joins the intake passage 1. The merging portion 13b of the exhaust return passage 13a with the intake passage 1 is located on the downstream side of the air cleaner 18. The end of the exhaust / return passage 13a located at the confluence 13b is opened so as to face the downstream side in the flow direction of the intake passage 1.

A rotating body 15 is provided at the confluence portion 13b of the exhaust / return passage 13a with the intake passage 1. The rotating body 15 includes a circular bottom surface 15a located on the downstream side, and a cylindrical portion 16 having an exhaust gas return gas retention space L inside a peripheral wall portion 15b rising from the peripheral edge of the bottom surface 15a to the upstream side. It is a member that forms a cylindrical shape. As shown in FIG. 2, the outer peripheral portion of the bottom surface 15a has a tapered shape that reduces in diameter toward the downstream side in the intake flow direction. The tubular portion 16 has a retention space L for exhaust gas returning gas inside the cylindrical peripheral wall portion 15b. A guide hole 16a, which is a through hole that passes through the inside and outside, is formed in the peripheral wall portion 15b. The retention space L and the space in the intake passage 1 communicate with each other through the guide hole 16a.

The rotating body 15 is arranged so that the axial direction of the tubular portion 16 is along the flow direction of the intake air of the intake passage 1 and the opening of the tubular portion 16 faces the upstream side. The downstream end of the bent portion provided at the end of the exhaust / return passage 13a is connected to the opening of the tubular portion 16. After penetrating the pipe wall of the intake passage 1, the exhaust return passage 13a bends in the intake passage 1 toward the downstream side in the flow direction of the intake air, and its downstream end is connected to the retention space L. That is, the exhaust / return passage 13a communicates with the intake passage 1 through the retention space L and the guide hole 16a.

In this embodiment, the opening on the upstream side of the tubular portion 16 is in sliding contact with the end portion of the exhaust / return passage 13a, and the rotating body 15 is rotatable around the tubular axis thereof. The rotating body 15 is rotatably supported by a rolling bearing or the like provided between the tubular portion 16 and the exhaust / return passage 13a or between the tubular portion 16 and the inner wall of the intake passage 1. The configured configuration may be adopted.

On the downstream side of the rotating body 15, a driving source 17 for applying a driving force to the rotating body 15 for rotating the rotating body 15 is provided. The drive source 17 is supported in the intake passage 1 by a support column S provided inward from the peripheral surface of the intake passage 1. The drive source 17 is connected to the rotating body 15 by a driving force transmission path such as a gear or a shaft so that the driving force can be transmitted to the rotating body 15.

In this embodiment, the drive source 17 is an electric motor. The motor includes a motor main body 17a that generates a driving force, and a motor shaft portion 17b that protrudes upstream from the motor main body 17a so as to coincide with the tubular shaft of the tubular portion 16. The motor shaft portion 17b is inserted into a shaft hole 15c formed in the bottom surface 15a of the tubular portion 16. The motor shaft portion 17b and the tubular portion 16 are stopped by fitting (press fitting) between the motor shaft portion 17b and the shaft hole 15c, and the rotation of the motor is transmitted to the rotating body 15. The rotation speed of the drive source 17 can be controlled by the exhaust gas recirculation device control means 43, which will be described later. The drive source 17 may be arranged outside the intake passage 1 as long as the driving force can be transmitted to the rotating body 15.

As shown in FIGS. 3A and 3B, the guide hole 16a is in the same direction as the rotation direction of the rotating body 15 by the drive source 17 due to the flow of the exhaust gas recirculated gas introduced from the retention space L into the intake passage 1. It is set at a position where the rotational force (hereinafter referred to as "self-rotational force") is applied.

In this embodiment, the guide holes 16a include a pair of first guide holes 16b provided so as to sandwich the retention space L vertically, and a pair of second guide holes 16c provided so as to sandwich the retention space L left and right. To be equipped. The center lines of the first guide hole 16b and the second guide hole 16c are one of the radial center lines C1 and C2 of the tubular portion 16 in the direction around the cylinder axis (the same direction as the direction of the driving force applied by the motor). It is provided so as to be eccentric to. That is, the first guide hole 16b on the upper side of the stay space L is eccentric to the left side with respect to the vertical center line C1 in FIG. 3 (b), and the first guide hole 16b on the lower side of the stay space L is. It is eccentric to the right with respect to the center line C1. The second guide hole 16c on the right side of the retention space L is eccentric upward with respect to the center line C2 in the left-right direction, and the second guide hole 16c on the left side of the retention space L is eccentric downward with respect to the center line C2. To do. With such an arrangement of the guide holes 16a, the rotating body 15 is projected from the guide holes 16a by the momentum of the exhaust return gas introduced from the exhaust return passages 13a into the intake passage 1 through the guide holes 16a. A self-rotating force that rotates in the direction of the arrow is applied to the rotating body 15.

When the rotating body 15 rotates, a negative pressure is generated around the rotating body 15 according to the number of rotations of the rotating body 15 (the number of rotations per unit time). The exhaust gas recirculates according to the pressure state in the intake passage 1 adjusted by the opening degree of the exhaust recirculation valve 14 provided in the exhaust recirculation passage 13a and the negative pressure generated around the rotating body 15. It is introduced into the intake passage 1 from the passage 13a through the guide hole 16a. Here, for example, in the initial stage of starting the introduction of the exhaust gas to the intake air, the rotating body 15 is rotated by the driving force of the drive source 17, and after the introduction of the exhaust gas is increased by the rotation, the self-rotating force Therefore, the driving force from the driving source 17 may be reduced or controlled to be zero.

Further, in this embodiment, since the pressure adjusting throttle valve 5 for introducing the exhaust recirculation gas is arranged in the intake passage 1 upstream of the confluence portion 13b, the intake passage is opened and closed by opening and closing the pressure adjusting throttle valve 5. The pressure state in 1 can be adjusted. Therefore, the negative pressure generated in the intake passage 1 due to the rotation of the rotating body 15 and the negative pressure in the intake passage 1 generated by reducing the opening degree of the pressure adjusting throttle valve 5 are used in combination to generate the exhaust gas. The amount of introduction can be adjusted.

The electronic control unit (Electronic Control Unit) 40 included in the vehicle equipped with the engine E performs the supply of fuel and air to the engine E, the opening and closing of valves, and other controls (see FIG. 1). The electronic control unit 40 includes information on the rotation speed of the crankshaft C by the rotation sensor 32 included in the engine E, information on the intake air amount by the air flow sensor 31, and other information such as intake air temperature, intake pressure, exhaust temperature, and air-fuel ratio. Acquire various information and utilize the information for control.

The electronic control unit 40 includes an output control means 41 that operates the throttle valve 9 to adjust the amount of intake air introduced into the combustion chamber 10. The output control means 41, for example, when there is input information instructing acceleration based on the operation of the accelerator pedal performed by the driver, the intake air into the combustion chamber 10 according to the degree of the instructed acceleration. Control to increase the amount. In addition, if the acceleration instruction is canceled, control is performed to reduce the intake air amount. The output control means 41 performs control for adjusting the pressure of fuel injection by the fuel injection device 8, the timing of fuel injection, and other necessary controls according to the operating conditions.

Further, the electronic control unit 40 determines the exhaust gas return gas rate, which is a target for controlling the exhaust gas return gas rate, which is the ratio of the exhaust gas return gas to the intake air. The means 42 is provided. The exhaust gas return gas rate determining means 42 determines the target exhaust gas return gas rate according to a change in the actual load, which is the load of the engine E, which is actually occurring at that time.

The actual load information is acquired by the electronic control unit 40 based on the rotation speed of the engine E controlled by the output control means 41, the opening degree of the valve in the intake passage 1, and various other information from various sensors. It can be estimated, or the electronic control unit 40 can estimate it based on various information. Since the actual load changes from moment to moment with the passage of time, the target exhaust gas return gas rate to be determined also changes from moment to moment according to the change in the actual load. The magnitude of the negative pressure generated around the rotating body 15 is based on the rotation speed of the motor which is the drive source 17, the opening degree of the exhaust / return valve 14, the pressure of the intake passage 1, and various other information from various sensors. It can be acquired by the electronic control unit 40, or it can be estimated by the electronic control unit 40 based on various information.

Further, the electronic control unit 40 includes an exhaust gas recirculation device control means 43 that controls the exhaust gas recirculation device 13. The exhaust gas recirculation device control means 43 controls the rotation speed of the motor of the drive source 17 based on the actual exhaust gas return gas rate and the target exhaust gas return gas rate. The amount of the exhaust gas introduced into the intake air changes according to the pressure state in the intake passage 1 adjusted by the opening degree of the exhaust gas return valve 14 and the negative pressure generated around the rotating body 15. The exhaust gas recirculation device control means 43 makes the actual exhaust gas return gas rate, which is the actual exhaust gas return gas rate at that time, close to the target exhaust gas return gas rate determined by the exhaust gas return gas rate determining means 42. The exhaust gas recirculation valve 14 is opened and closed, and the rotation speed of the motor is controlled to adjust the amount of the exhaust gas introduced into the intake air.

The information on the actual exhaust gas return gas rate can be predicted and estimated by the exhaust gas recirculation device control means 43 based on the intake air amount, the opening degree of the valve in the intake passage 1, the intake pressure, the rotation speed of the motor, and the like. .. Alternatively, a means for directly measuring the actual exhaust gas return gas rate may be provided in the intake port 11.

As described above, the self-rotating force acts on the rotating body 15 by the flow of the exhaust gas returning gas introduced from the residence space L through the guide hole 16a into the intake passage 1. The exhaust gas recirculation device control means 43 controls the rotation speed of the drive source 17 in consideration of the self-rotational force. The self-rotating force is based on the magnitude of the negative pressure generated around the rotating body 15, the number of rotations of the drive source 17, the opening degree of the exhaust / recirculation valve 14, the pressure of the intake passage 1, and various other information from various sensors. Can be acquired by the electronic control unit 40, or can be estimated by the electronic control unit 40 based on various information. Here, a sensor capable of detecting the rotation speed of the rotating body 15 may be provided, and information on the actual rotation speed of the rotating body 15 based on the driving force and the self-rotating force may be utilized for the control thereof.

In the present invention, as described above, by adopting the configuration in which the rotating body 15 is provided at the confluence portion 13b of the exhaust / return passage 13a with the intake passage 1, a negative pressure is applied around the rotating body 15 by the rotation of the rotating body 15. It is possible to generate the exhaust gas and smoothly introduce the exhaust gas in the exhaust return passage 13a into the intake air through the guide hole 16a. Therefore, when introducing the exhaust gas, it is not necessary to reduce the opening degree of the pressure adjusting throttle valve 5 arranged in the intake passage 1 on the upstream side of the merging portion 13b. Therefore, the exhaust gas is smoothly introduced into the intake air without obstructing the flow of fresh air introduced from the upstream side. As a result, a response delay (time lag) is less likely to occur in response to the driver's acceleration request, and a comfortable driving feeling is maintained. If the exhaust gas is smoothly introduced into the intake air by the rotation of the rotating body 15, it is possible to omit the installation of the pressure adjusting throttle valve 5 arranged in the intake passage 1 on the upstream side of the merging portion 13b. Is.

Further, since the rotating body 15 is arranged so that the axial direction of the tubular portion 16 is along the flow direction of the intake air in the intake passage 1, it is difficult to obstruct the flow of the intake air in the intake passage 1. There is. Therefore, it is possible to prevent a decrease in the intake air amount.

Further, by setting the arrangement of the guide holes 16a, a self-rotating force is applied to the rotating body 15. Therefore, the rotating body 15 can rotate without relying only on the driving force of the driving source 17.

Further, the exhaust gas recirculation device control means 43 can adjust the rotation of the rotating body 15 by the driving force of the driving source 17 and the self-rotating force. Therefore, the drive source 17 can be efficiently operated by rotating the rotating body 15 with its own rotational force while reducing the rotation speed of the drive source 17.

1 Intake passage 2 Exhaust passage 13 Exhaust gas recirculation device 13a Exhaust recirculation passage 13b Confluence part 15 Rotating body 15b Peripheral wall part 16 Cylindrical part 16a Induction hole 17 Drive source 17a Motor body 17b Motor shaft part 40 Electronic control unit 41 Output control means 42 Exhaust gas return gas rate determining means 43 Exhaust gas recirculation device control means L Retention space

Claims (5)

An intake passage that introduces intake air into the combustion chamber,
The exhaust passage that sends out the exhaust from the combustion chamber and
An exhaust gas recirculation device that introduces a part of the exhaust gas into the intake gas as an exhaust gas return gas through the exhaust gas return passage connecting the intake passage and the exhaust passage.
A rotating body provided at the confluence of the exhaust / return passage with the intake passage,
A drive source that applies a driving force to the rotating body to rotate the rotating body,
With
An engine control device in which an exhaust return gas in the exhaust return passage is introduced into the intake passage by a negative pressure generated around the rotating body due to the rotation of the rotating body. The rotating body is provided with a tubular portion having an exhaust return gas retention space inside the peripheral wall portion.
The exhaust return passage is connected to the retention space,
The retention space and the intake passage are communicated with each other by an guide hole penetrating the peripheral wall portion.
The engine control device according to claim 1, wherein the rotating body rotates around a tubular axis of the tubular portion. The rotating body is arranged so that the axial direction of the tubular portion is along the flow direction of the intake passage.
The engine control device according to claim 2, wherein the exhaust / reflux passage is connected to an upstream end portion of the tubular portion. The guide hole is set at a position where a rotational force in the same direction as the rotation direction of the rotating body by the drive source is applied by the flow of the exhaust gas returning gas introduced from the retention space to the intake passage. The engine control device according to 3. Exhaust gas return gas rate determining means for determining a target exhaust gas return gas rate, which is a ratio of the exhaust gas return gas to the intake air, according to the load of the engine.
An exhaust gas recirculation device control means that controls the actual exhaust gas return gas rate, which is the actual exhaust gas return gas rate in the intake air, to approach the target exhaust gas return gas rate according to the load of the engine at that time.
With
The drive source is a motor
The engine according to any one of claims 1 to 4, wherein the exhaust gas recirculation device control means controls the rotation speed of the motor based on the actual exhaust gas recirculation gas rate and the target exhaust gas recirculation gas rate. Control device.

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