JP2015129478A - Intake controller and intake control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake controller and an intake control method capable of operating an internal combustion engine in a miller cycle without regulating the actuation timing of an intake valve.SOLUTION: An intake controller in one aspect of the present invention is an intake controller for controlling the air intake of an internal combustion engine, comprises a control unit (11) controlling the opening of a throttle valve disposed in an intake system of the internal combustion engine to either an open direction or a closed direction in an intake stroke of the internal combustion engine, and initializes the opening of the throttle valve after the intake stroke.

Description

  The present invention relates to an intake control device for an internal combustion engine, and more particularly to an intake control device and an intake control method that enable operation in a mirror cycle.

  Conventionally, an internal combustion engine that operates in an Otto cycle is generally known (see, for example, Patent Document 1). In an internal combustion engine operating in the Otto cycle, the compression ratio and the expansion ratio are equal. On the other hand, there is known an internal combustion engine (hereinafter referred to as “Miller cycle engine”) that operates in a Miller cycle that substantially increases the expansion ratio rather than the compression ratio to improve the thermal efficiency. In the Miller cycle engine, the expansion ratio is substantially made larger than the compression ratio by reducing the intake amount by late closing or early closing of the intake valve. In the Miller cycle engine that is widely used in four-wheeled vehicles, the slow closing method that delays the closing timing of the intake valve is the mainstream. In a late-closed Miller cycle engine, after the piston reaches bottom dead center in the intake process, the intake valve is kept open for a certain period of time, so that a part of the air-fuel mixture in the cylinder is moved to the intake port side. The intake volume is reduced by backflow.

JP-A-5-187237

  According to the late-closed or early-closed Miller cycle engine, it is necessary to adjust the operation timing of the intake valve, which complicates the intake valve control system. In particular, in the case of a two-wheeled vehicle with a small displacement, the space for mounting a control device is limited, and adopting the slow closing method or the early closing method similar to that of the four wheels complicates the device configuration, Cost increases.

  An object of the present invention is to provide an intake control device and an intake control method that enable an internal combustion engine to operate in a mirror cycle without adjusting the operation timing of the intake valve.

An intake air control apparatus according to an aspect of the present invention is an intake air control apparatus that controls intake air of an internal combustion engine. In an intake process of the internal combustion engine, an opening degree of a throttle valve provided in an intake system of the internal combustion engine is set in an opening direction or It has a configuration of an intake control device characterized by including a control unit that changes to any one of the closing directions and initializes the opening of the throttle valve after the intake step.
According to this configuration, since the opening degree of the throttle valve is changed in the middle of the intake process, even if the intake valve is open, intake is limitedly performed in a part of the entire process of the intake process. . For this reason, a substantial compression ratio can be lowered compared with the case where intake is performed over the entire stroke of the intake process. Therefore, the expansion ratio can be made substantially larger than the compression ratio regardless of the operation timing of the intake valve, and the internal combustion engine can be operated in a mirror cycle.

  In the intake control device, for example, the control unit changes an opening of the throttle valve in a closing direction in the intake process, and after the intake process, before the start of the next intake process, The opening is returned to the original state. According to this configuration, intake is limitedly performed in a part of the entire process of the intake process until the throttle valve is closed. For this reason, a substantial compression ratio can be lowered compared with the case where intake is performed over the entire stroke of the intake process.

  In the intake control device, for example, the control unit changes the opening degree of the throttle valve in the closing direction with the intake valve being opened, and the intake valve is closed with the intake valve being closed. Before starting, the opening degree of the throttle valve is returned to the original state. According to this configuration, intake is limitedly performed in a part of the steps of the intake process in which the intake valve is opened until the throttle valve is closed. For this reason, a substantial compression ratio can be lowered compared with the case where intake is performed over the entire stroke of the intake process.

  In the intake control device, for example, the control unit may change the opening degree of the throttle valve in a closing direction by a return spring in the intake process. According to this configuration, in the intake process, the opening of the throttle valve can be instantaneously switched to the closed state by the return spring.

  In the intake control device, for example, the control unit returns the opening of the throttle valve to the original state by an actuator in a period after the intake process and before the start of the next intake process. . According to this configuration, the throttle valve opening can be gradually returned to the original state by the actuator after the intake step.

  In the intake control device, for example, the control unit changes the opening degree of the throttle valve in the opening direction in the intake process, and after the intake process, before the start of the next intake process, The opening is returned to the original state. According to this configuration, intake is limitedly performed in a part of the steps of the intake process after the throttle valve is opened. For this reason, a substantial compression ratio can be lowered compared with the case where intake is performed over the entire stroke of the intake process.

  In the intake control device, for example, the control unit changes the opening degree of the throttle valve in the opening direction with the intake valve being opened, and the intake section is closed with the intake valve being closed. Before starting, the opening degree of the throttle valve is returned to the original state. According to this configuration, intake is limitedly performed in a part of the steps of the intake process in which the intake valve is opened after the throttle valve is opened. For this reason, a substantial compression ratio can be lowered compared with the case where intake is performed over the entire stroke of the intake process.

An intake control method according to an aspect of the present invention is an intake control method for controlling intake air of an internal combustion engine. In an intake process of the internal combustion engine, an opening degree of a throttle valve provided in an intake system of the internal combustion engine is set in an opening direction or It has a configuration of an intake control method characterized by changing to any one of the closing directions and initializing the opening degree of the throttle valve after the intake step.
According to this configuration, since the opening degree of the throttle valve changes during the intake process, intake is limitedly performed in a part of the entire process of the intake process even when the intake valve is open. . For this reason, a substantial compression ratio can be lowered compared with the case where intake is performed over the entire stroke of the intake process. Therefore, the expansion ratio can be made substantially larger than the compression ratio regardless of the operation timing of the intake valve, and the internal combustion engine can be operated in a mirror cycle.

  According to one aspect of the present invention, the internal combustion engine can be operated in a mirror cycle without adjusting the operation timing of the intake valve.

It is a figure for demonstrating the example of application of the intake control device by 1st Embodiment of this invention. It is a figure for demonstrating the control action of the intake control device by 1st Embodiment of this invention, and is a figure for demonstrating an example of the relationship between the stroke of an internal combustion engine, and a throttle valve opening degree. It is a figure for demonstrating the control action of the intake control device by 1st Embodiment of this invention, and is a figure for demonstrating an example of the relationship between the opening degree of a throttle valve, and the intake passage area of a throttle valve, (A) is a characteristic diagram showing an example of the characteristic of the intake passage area with respect to the throttle valve opening, and (B) is an example of a correspondence relationship between the throttle valve opening and intake passage area S and the valve body of the throttle valve. It is a figure for demonstrating. It is a figure for demonstrating the control action of the intake control device by 1st Embodiment of this invention, and is a figure for demonstrating an example of the relationship between a throttle valve opening degree and intake air quantity. It is a figure for demonstrating the control action of the intake control device by 2nd Embodiment of this invention, and is a figure for demonstrating an example of the relationship between the stroke of an internal combustion engine, and a throttle valve opening degree.

[First embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
(Description of configuration)
FIG. 1 is a diagram for explaining an application example of an intake air control device 1 according to the first embodiment of the present invention. The intake air control device 1 controls intake air of the internal combustion engine 100 and includes a control unit 11 for controlling the opening degree of the throttle valve 108 of the internal combustion engine 100. The control unit 11 changes the opening degree of the throttle valve 108 in either the opening direction or the closing direction in the intake process of the internal combustion engine 100, and initializes the opening degree of the throttle valve 108 after the intake process. Here, “open direction” refers to the direction in which the opening degree of the throttle valve 108 increases, and “closed direction” refers to the direction in which the opening degree of the throttle valve 108 decreases. Specifically, in FIG. 3B described later, as indicated by an arrow P, the valve body 109 of the throttle valve 108 is in parallel with the intake flow passage (that is, the valve body 109 is opened). ) Corresponds to the opening direction of the throttle valve 108. In addition, as indicated by an arrow Q in FIG. 3B, the rotation direction of the valve body 109 when the valve body 109 goes to a state orthogonal to the intake flow path (that is, the valve body 109 is closed). Corresponds to the closing direction of the throttle valve 108. In the first embodiment, the control unit 11 changes the opening degree of the throttle valve 108 in the closing direction in the intake process, and initially sets the opening degree of the throttle valve 108 after the intake process and before the start of the next intake process. And return to the original opening in the normal state. Here, the opening degree in the normal state refers to the opening degree of the throttle valve 108 when performing normal operation in the Otto cycle, not in the mirror cycle.

  An accelerator opening signal SA from an accelerator opening sensor 3 provided so as to be interlocked with the accelerator pedal 2 is input to the intake control device 1. Further, the rotary shaft of the motor 4 is coupled to the valve body 109 of the throttle valve 108 of the internal combustion engine 100 via the transmission 5. However, the transmission 5 may be omitted, and the rotating shaft of the motor 4 may be coupled to the valve body 109. The intake control device 1 controls the opening of the throttle valve 108 by performing drive control of the motor 4 based on the accelerator opening signal SA from the accelerator opening sensor 3. Further, a throttle opening signal SS from a throttle opening sensor 6 provided so as to be interlocked with the valve body 109 of the throttle valve 108 is input to the intake control device 1 as a feedback signal.

  A valve element 109 of a throttle valve 108 provided in the internal combustion engine 100 is biased in a direction to be returned to a fully closed position by a return spring 111. When the operation amount (depression amount) of the accelerator pedal 2 is increased, the motor 4 drives the valve body 109 via the transmission 5, thereby opening the valve body 109 and increasing the opening of the throttle valve 108. Conversely, when the amount of operation of the accelerator pedal 2 is reduced, the opening degree of the throttle valve 108 is reduced.

  The internal combustion engine 100 is a four-cycle engine in which an intake process, a compression process, a combustion process, and an exhaust process are completed while the piston 101 reciprocates twice inside the cylinder 102. An intake valve 104 that opens and closes the outlet of the intake port 103 and an exhaust valve 113 that opens and closes the inlet of the exhaust port 112 are provided in a cylinder head (not indicated) positioned above the cylinder 102. The intake valve 104 is swung by the cam 105 and opened in the intake process, and the exhaust valve 113 is swung by the cam 114 and opened in the exhaust process.

  The intake port 103 is provided with an injector 106 for injecting fuel. The amount of fuel injected by the injector 106 is controlled by an engine controller (not shown). An intake manifold 107 is provided upstream of the injector 106 (upstream of intake air), and a throttle valve 108 is further provided upstream thereof. A valve shaft 110 to which a valve body 109 for adjusting the amount of intake air is attached is pivotally supported in a throttle chamber (not shown) that forms a housing portion of the throttle valve 108. The output shaft of the transmission 5 is coupled to one extension end of the valve shaft 110, and the throttle opening sensor 6 is coupled to the other extension end of the valve shaft 110.

  The valve shaft 110 is provided with a return spring 111 for elastically returning the valve body 109 to the fully closed position. An example of attaching the return spring 111 is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-189542 by the same applicant as the present application. When the control unit 11 energizes the motor 4, the motor 4 rotates, the rotation of the motor 4 is decelerated by the transmission 5 and transmitted to the valve shaft 110, the valve body 109 is driven to open, and the motor 4 is energized. Is turned off, the valve body 109 is forcibly returned to the fully closed position by the elastic force of the return spring 111.

(Description of operation)
Next, the operation of the intake control device 1 according to the first embodiment of the present invention will be described with reference to FIGS.
FIG. 2 is a diagram for explaining the control operation of the intake control device 1, and is a diagram for explaining an example of the relationship between each stroke of the internal combustion engine 100 and the throttle valve opening φ. In FIG. 2, the horizontal axis represents the rotation angle θ of a crankshaft (not shown) corresponding to the reciprocating motion of the piston 101, and the vertical axis represents the position of the piston 101. FIG. 3 is also a diagram for explaining the control operation of the intake control device 1, and is a diagram for explaining an example of the relationship between the throttle valve opening φ and the intake passage area S. Here, FIG. 3A is a characteristic diagram showing an example of the characteristic of the intake passage area S with respect to the throttle valve opening φ. 3A, the horizontal axis represents the opening φ of the throttle valve 108 (that is, the throttle valve opening φ), and the vertical axis represents the intake passage area S of the throttle valve 108. FIG. 3B is an enlarged view of the throttle valve 108 shown in FIG. 1, and the throttle valve opening φ and intake passage area S shown in FIG. 3A and the valve of the throttle valve 108 shown in FIG. It is a figure for demonstrating the correspondence between the rotation angles of the body 109. FIG. The throttle valve opening φ shown in the example of FIG. 3A is represented by the rotation angle (0 to 90 degrees) of the valve element 109 of the throttle valve 108, as shown in FIG. 3B. In the present embodiment, the rotation angle of the valve body 109 when the valve body 109 is orthogonal to the intake flow path (fully closed state) is 0 degree, and the valve body 109 is the intake flow path. The rotation angle of the valve body 109 in a state parallel to (a fully open state) is 90 degrees. However, in reality, if the rotation angle of the valve body 109 is near 0 degrees, the throttle valve 108 is fully closed, and if the rotation angle of the valve body 109 is about 90 degrees, the throttle valve 108 is fully opened. FIG. 4 is a diagram for explaining the control operation of the intake control device 1 and is a diagram for explaining an example of the relationship between the throttle valve opening φ and the intake air amount A. FIG.

  Schematically, the control unit 11 of the intake control device 1 controls the opening φ of the throttle valve 108 so that the throttle valve 108 is normally opened at the start of the intake process. By changing the valve 108 in the closing direction, the opening φ of the throttle valve 108 is decreased, and the intake amount A in the intake process is suppressed.

  The operation will be described in detail with reference to FIG. In FIG. 2, the horizontal axis represents the rotation angle θ of a crankshaft (not shown) corresponding to the reciprocating motion of the piston 101 of the internal combustion engine 100. In the example of FIG. 2, a rotation angle of 0 to 720 ° corresponding to two rotations of the crankshaft is repeatedly expressed as the rotation angle θ corresponding to the period from the intake process to the discharge process. In the example of FIG. 2, the intake process and the combustion stroke correspond to a period during which the piston 101 moves from the top dead center to the bottom dead center, and the compression process and the discharge process perform the piston 101 from the bottom dead center to the top dead center. It corresponds to the period of moving to. However, the relationship between each process and the rotation angle θ is not limited to the example of FIG. 2 and can be arbitrarily set within a range in which the internal combustion engine 100 can be operated in a mirror cycle.

  In FIG. 2, during the intake process, the intake valve 104 (FIG. 1) is opened, the exhaust valve 113 (FIG. 1) is closed, and the piston moves from top dead center to bottom dead center. Further, during the compression process, the piston 101 moves from the bottom dead center toward the top dead center with both the intake valve 104 and the exhaust valve 113 being closed. During the combustion stroke, the piston moves from the top dead center to the bottom dead center with both the intake valve 104 and the exhaust valve 113 closed. During the exhaust process, the piston moves from the bottom dead center to the top dead center with the intake valve 104 closed and the exhaust valve 113 open.

  When the rotation angle θ is close to 0 °, that is, when the intake process starts, the opening φ of the throttle valve 108 is set to a normal opening φopen indicating an open state by the control unit 11, and the rotation angle The opening degree φopen is maintained until θ reaches a predetermined rotation angle θclose. In this embodiment, the opening φclose is assumed to be the opening when the throttle valve 108 is fully closed (that is, 0 degrees), but is not limited to this example, and operation in a mirror cycle is possible. In such a limit, the opening φclose may be an opening at which an intake air flow can be generated. The opening degree φopen is determined by the control unit 11 based on an accelerator opening signal SA indicating an operation amount of the accelerator pedal 2, for example. The control unit 11 controls the rotation angle of the valve element 109 in accordance with the opening φ of the throttle valve 108, whereby the intake passage area S inside the throttle chamber forming the housing portion of the throttle valve 108 (that is, the progress of the intake flow). The projected area of the valve element 109 when viewed from the direction is adjusted. As illustrated in FIG. 3A, the intake passage area S increases as the opening φ of the throttle valve 108 increases. As the intake passage area S increases, the intake air amount A increases. In this case, as illustrated in FIG. 3B, when the valve body 109 of the throttle valve 108 rotates in the opening direction P, the opening φ of the throttle valve 108 increases and the intake passage cross-sectional area S increases. As a result, the intake air amount A increases. Conversely, when the opening φ of the throttle valve 108 decreases and the intake passage area S decreases, the intake air amount A decreases. In this case, as illustrated in FIG. 3B, when the valve body 109 of the throttle valve 108 rotates in the closing direction Q, the opening φ of the throttle valve 108 decreases and the intake passage cross-sectional area S decreases. As a result, the intake air amount A decreases. Note that the relationship between the opening φ of the throttle valve 108 and the intake passage area S is not limited to the example of FIG. 3 and can be set arbitrarily.

  As described above, from the state where the opening φ of the throttle valve 108 is set to the opening φopen at the start of the intake process, the intake valve 104 is opened as the intake process proceeds, and the piston 101 is moved down from the top dead center. When moving toward the dead point, the intake flow that has passed through the throttle valve 108 due to the negative pressure generated in the cylinder 102 is introduced into the cylinder 102 through the intake port 103. At this time, the fuel injection amount corresponding to the intake air amount is calculated by an engine controller (not shown). Then, fuel is injected by the injector 106 into the intake air flow passing through the intake port 103, and an air-fuel mixture is sent into the cylinder 102. Here, as shown by the broken line in the upper part of FIG. 4, in the intake process, the opening φ of the throttle valve 108 is set to the normal (steady operation) opening φopen during the period from the rotation angle θ to 0 to θclose. In this case, as indicated by a broken line in the lower part of FIG. 4, the intake air amount A tends to gradually decrease from the midpoint of the intake process after gradually increasing with the progress of the rotation angle θ in the intake process. Note that the intake loss can be reduced by setting the opening φ of the throttle valve 108 to be higher than the normal value until the intake step with a large intake amount A is in progress.

  When the rotation angle θ reaches the predetermined rotation angle θclose in the intake process, the control unit 11 causes the valve body 109 of the throttle valve 108 to be moved to the throttle valve by the elastic force of the return spring 111 in a state where the intake valve 104 is opened. As shown by the broken line in the upper part of FIG. 4, the opening φ of the throttle valve 108 is changed from the opening φopen indicating the open state to the opening φclose indicating the closed state. . That is, when the control unit 11 determines that the position of the piston 101 is at a predetermined position in the intake process, the control unit 11 operates an actuator (not shown) to rotate in the forward direction to suppress the rotational driving force and use the elastic force of the return spring 111. Then, control for closing the throttle valve 108 is started until the opening φ of the throttle valve 108 reaches a predetermined opening φclose.

  Further, when the controller 11 determines that the opening φ of the throttle valve 108 has substantially reached a predetermined opening φclose in the intake process, the controller 11 stops the forward rotation operation of the actuator and suppresses the rotational driving force, thereby returning the return spring. The operation of closing the throttle valve 108 is stopped via 111. In the example of FIG. 2, the opening φ of the throttle valve 108 starts to decrease from the opening φopen when the rotation angle θ becomes the rotation angle θclose, and the time when the intake process ends (that is, the rotation angle θ is 180 °). The opening degree φclose is reached at a point in time.

  Here, when the rotation angle θ reaches the predetermined rotation angle θclose, the throttle valve 108 is controlled to be closed as described above, and as a result, the intake air amount A decreases rapidly as shown by the broken line in the lower part of FIG. To do. In FIG. 4, the intake air amount A when the opening degree φ is maintained at the opening degree φopen is indicated by a one-dot chain line. As can be understood from FIG. 4, when the opening degree φ is changed from the opening degree φopen to the opening degree φclose compared to the intake air amount A (one-dot chain line) when the opening degree φ is maintained at the opening degree φopen. The intake amount A (broken line) decreases, and the total amount (integrated value) of the intake amount A in the intake process decreases.

  As described above, when the opening φ of the throttle valve 108 is changed from the opening φopen to the opening φclose, the amount of the air-fuel mixture is reduced as compared with the case where the opening φφ is maintained. The rotation speed decreases. For this reason, when it is necessary to maintain the rotational speed of the internal combustion engine 100 at the same rotational speed as when the opening degree φopen is maintained, as shown by the solid line in the upper stage of FIG. During the period from 0 to θclose, the opening φ indicating the open state is increased to the opening φopen2 which is larger than the opening φopen during the above-described steady operation, and as shown by the solid line in the lower part of FIG. Just increase A.

  Subsequently, when the rotation angle θ reaches around 180 °, the intake valve 104 is closed, the compression process is started, and the piston 101 starts to rise. The controller 11 gradually returns the opening φ of the throttle valve 108 in the opening direction by an actuator (not shown) during the period from the compression process to the exhaust process after the intake process. That is, the control unit 11 rotates the valve body 109 of the throttle valve 108 in the opening direction in which the throttle valve is opened, opposite to the closing direction, by the actuator while the intake valve 104 is closed. The degree φ is gradually switched from the opening φclose indicating the closed state to the normal opening φopen indicating the open state, and the operation of closing the throttle valve 108 is stopped.

  When the control unit 11 stops the operation of closing the throttle valve 108 and then determines that the intake valve 104 is closed and the intake process is completed, the control unit 11 reversely rotates an actuator (not shown), and returns the throttle via the return spring 111. An operation of gradually opening the opening φ of the valve 108 to return to the original normal opening φopen is started. The operation of gradually opening the opening φ of the throttle valve 108 is continued from the compression process to the discharge process. Here, in the compression process, the piston 101 rises from the bottom dead center to the top dead center. In this case, from the viewpoint of the amount of change in the internal volume of the cylinder 102, the compression ratio (= exhaust volume / compression volume) is the same as that of the conventional Otto cycle, but the mixing introduced into the cylinder 102 in the above-described intake process. If attention is paid to the amount of qi, the substantial compression ratio decreases.

  Subsequently, when the rotation angle θ reaches near 360 ° and the piston 101 reaches near the top dead center, the compressed air-fuel mixture is ignited by a spark plug (not shown), and the process of the internal combustion engine 100 is performed as a combustion process. Proceed to In the combustion stroke, the piston 101 descends from the top dead center toward the bottom dead center. Subsequently, when the rotation angle θ reaches around 540 °, the exhaust valve 113 is opened, the piston 101 starts to descend, and the process of the internal combustion engine 100 proceeds to the exhaust process.

  In the exhaust process, the piston 101 rises from the bottom dead center toward the top dead center, and exhausts the combustion gas inside the cylinder 102. When the rotation angle θ returns to around 0 °, the opening φ of the throttle valve 108 is initialized to a predetermined opening φopen. However, as described above, the value of the opening degree φopen changes sequentially according to the operation amount of the accelerator pedal 2, for example. When the control unit 11 determines that the position of the piston 101 has reached the top dead center of the exhaust process, the control unit 11 stops the reverse rotation operation of an actuator (not shown) and stops the operation of opening the throttle valve 108 via the return spring 111. .

  As described above, the control unit 11 changes the opening φ of the throttle valve 108 in the closing direction in a state in which the intake valve 104 is opened in the intake process described above, and the intake valve 104 is closed in the compression process and the combustion stroke. In this state, the opening φ of the throttle valve 108 is returned to the original state before the start of the next intake process. The opening φ of the throttle valve 108 is set to reach a predetermined opening φopen until the position of the piston 101 reaches the bottom dead center of the intake process. When the rotation angle θ returns to around 0 ° (ie, around 720 °), the control unit 11 determines that the position of the piston 101 has reached a predetermined position in the intake process, and again from the intake process to the exhaust process described above. Repeat a series of controls.

  If attention is paid to the intake process among the processes described above, the amount of the air-fuel mixture introduced into the cylinder 102 is the same as when the compression ratio is reduced. If attention is paid to the internal volume of the cylinder 102, the compression ratio (= exhaust volume / compression volume) and the expansion ratio (= expansion volume / intake volume) are equal. Accordingly, with respect to the amount of air-fuel mixture introduced into the cylinder 102 in the intake process, the same result as that obtained when the expansion ratio is made larger than the compression ratio can be obtained, and the operation can be performed in the mirror cycle. Therefore, the thermal efficiency of the internal combustion engine 100 can be improved. In addition, even when the value of the opening degree φopen indicating the open state changes according to the operation amount of the accelerator pedal 2, the same effect as that obtained when the expansion ratio is made larger than the compression ratio can be obtained. Operation in the mirror cycle can be maintained.

  In other words, the control to close the opening φ of the throttle valve 108 is started from the middle of the intake process to the end of the intake process, and the intake amount introduced into the cylinder 102 decreases. Further, the throttle valve 108 gradually opens from the start of the compression process to the end of the exhaust process. That is, with the intake valve 104 closed, the opening φ of the throttle valve is returned to a predetermined opening. Therefore, the opening φ of the throttle valve 108 does not affect the expansion ratio or the compression ratio in the processes after the intake process (compression, combustion, exhaust). Further, in the intake process, the opening φ of the throttle valve 108 is closed from the normal opening φopen to the predetermined opening φclose, so that the expansion ratio is relatively increased by reducing the intake air amount A. . Therefore, the expansion ratio can be substantially increased without reducing the compression ratio of the main body of the internal combustion engine 100, so that the combustion efficiency is improved.

The main features of the first embodiment described above will be summarized.
-The opening degree φ of the throttle valve 108 is changed during the intake process, and the throttle valve 108 is rapidly closed. In this case, by closing the throttle valve 108 using the elastic force of the return spring 111, the burden on the motor is reduced without impairing the responsiveness when controlling the opening φ of the throttle valve 108. Intake loss can be reduced by making the opening φ larger than the normal value in a region where the intake speed is high.
After the intake process is completed and before the next intake process, the opening φ of the throttle valve 108 is gradually returned to the original value using the actuator. By gradually returning the opening φ of the throttle valve 108 from the compression process after the intake process to the exhaust process, a sufficient time for driving the actuator with the motor can be secured. This makes it possible to reduce the size of the motor.

  As described above, according to the first embodiment, intake is limited in a part of the entire process of the intake process, and intake is limited in the remaining period of the intake process, so that the entire process of the intake process is performed. The intake amount can be reduced and the substantial compression ratio can be reduced as compared with the case where intake is performed. Therefore, by controlling the rotation angle θclose that determines the opening / closing timing of the throttle valve 108 and the opening φ of the throttle valve, the expansion ratio is substantially larger than the compression ratio without adjusting the operation timing of the intake valve. can do. For this reason, it becomes possible to drive the internal combustion engine 100 in a mirror cycle, and to improve fuel efficiency.

Further, according to the first embodiment, the opening φ of the throttle valve 108 is rapidly closed by the return spring 111 in the intake process, so that the burden on the motor can be reduced. In addition, compared with the case where the throttle valve 108 is directly closed by the motor without using the return spring 111, the responsiveness when switching the opening φ of the throttle valve 108 can be improved.
In addition, according to the first embodiment, since the opening φ of the throttle valve 108 is gradually opened by the actuator, the time required for the operation of the actuator can be secured, and the motor for driving the actuator can be downsized. Can be achieved.

Further, according to the first embodiment, a mirror cycle can be realized without using a camshaft phase control device for driving the cams 105 and 114. That is, the mirror cycle can be realized without adjusting the operation timing of the intake valve 104.
Further, by controlling the opening / closing timing of the throttle valve 108 and the opening φ of the throttle valve 108, the relative expansion ratio with respect to the compression ratio can be properly controlled. Further, if the opening φ of the throttle valve 108 in the intake process is increased, intake loss can be reduced. In addition, flexible intake control is possible by adjusting the opening / closing timing and opening of the throttle valve 108.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a diagram for explaining the control operation of the intake control device according to the second embodiment of the present invention, and is a diagram for explaining an example of the relationship between the stroke of the internal combustion engine and the throttle valve opening.
In the first embodiment described above, the opening φ of the throttle valve 108 is changed in the closing direction during the intake process. However, in the second embodiment, the opening φ of the throttle valve 108 is changed in the opening direction during the intake process. To change. About others, it is the same as that of 1st Embodiment mentioned above.

  In the second embodiment, when the rotation angle θ reaches a predetermined rotation angle θopen in the intake process, the control unit 11 causes the valve body 109 of the throttle valve 108 to be throttled by an actuator (not shown) while the intake valve is opened. The valve is rotated in the opening direction (opening direction), and the opening φ of the throttle valve 108 is switched from the opening φclose indicating the closed state to the opening φopen indicating the open state.

  Then, after the intake process and before the start of the next intake process, the opening φ of the throttle valve 108 is returned to the original state. That is, the control unit 11 uses the elastic force of the return spring 111 to close the valve body 109 of the throttle valve 108 in the direction in which the throttle valve is closed (opposite to the opening direction) while the intake valve 104 is closed. The opening degree φ of the throttle valve 108 is gradually switched from the opening degree φopen indicating the open state to the opening degree φclose indicating the closed state. As a result, the amount of the air-fuel mixture introduced into the cylinder 102 is the same as when the expansion ratio is made larger than the compression ratio, as in the first embodiment.

  Further explanation will be made with reference to FIG. 5. In the second embodiment, the opening φ of the throttle valve 108 is substantially closed by the control unit 11 at the time when the rotation angle θ is close to 0 ° and the intake process is started. It is a value in the vicinity of the opening φclose indicating the state. When the rotation angle θ reaches a predetermined rotation angle θopen after the intake process starts, the opening θ of the throttle valve 108 reaches a predetermined opening φclose. Therefore, in the second embodiment, in the intake process, the opening φ of the throttle valve 108 is in the vicinity of the opening φclose indicating a substantially closed state until the rotation angle θ reaches the predetermined rotation angle θopen from around 0 °. The throttle valve 108 is generally closed.

  When the rotation angle θ reaches a predetermined rotation angle θopen in the intake process, the control unit 11 rapidly rotates the valve body 109 in the opening direction (direction in which the valve body 109 opens) by an actuator (not shown). The opening φ is rapidly changed from the opening φclose indicating the closed state to φopen indicating the open state. When the opening φ of the throttle valve 108 changes to the opening φopen, an intake air flow is generated in the throttle valve 108 and the air-fuel mixture is introduced into the cylinder 102. When the rotation angle θ reaches around 180 °, the intake valve 104 is closed and the intake process is completed. The control unit 11 gradually closes the valve body 109 in the closing direction (the direction in which the valve body 109 is closed) by using the elastic force of the return spring 111 after the intake process and before the start of the next intake process. Rotate to gradually return the opening φ of the throttle valve 108 in the closing direction. In this case, for example, a damper is provided for suppressing the speed of rotation of the valve element 109 by the return spring 111 as necessary.

  Thus, in the second embodiment, the intake amount A in the intake process is suppressed by controlling the opening φ of the throttle valve 108 in the opening direction during the intake process. Therefore, as in the first embodiment, the expansion ratio can be made substantially larger than the compression ratio without adjusting the operation timing of the intake valve 104, and the internal combustion engine 100 is operated in a mirror cycle to improve fuel efficiency. It becomes possible to improve.

  In the first and second embodiments described above, the present invention is expressed as an intake control device, but the present invention can also be expressed as an intake control method. In this case, the intake control method according to the present invention is an intake control method for controlling intake of the internal combustion engine 100. In the intake process of the internal combustion engine 100, the opening φ of the throttle valve 108 provided in the intake system of the internal combustion engine 100 is set. It can be expressed as an intake control method characterized by changing to either the opening direction or the closing direction and initializing the opening φ of the throttle valve 108 after the intake step. According to this intake control method, the expansion ratio is substantially larger than the compression ratio without adjusting the operation timing of the intake valve 104, as in the intake control devices according to the first and second embodiments described above. The internal combustion engine can be operated in a mirror cycle.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be arbitrarily modified or modified without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Intake control device 2 ... Accelerator pedal 3 ... Accelerator opening sensor 4 ... Motor 5 ... Transmission 6 ... Throttle opening sensor 11 ... Control part 100 ... Internal combustion engine 101 ... Piston 102 ... Cylinder 103 ... Intake port 104 ... Intake valve 105 ... Cam (intake)
DESCRIPTION OF SYMBOLS 106 ... Injector 107 ... Intake manifold 108 ... Throttle valve 109 ... Valve body 110 ... Valve shaft 111 ... Return spring 112 ... Exhaust port 113 ... Exhaust valve 114 ... Cam (exhaust)

Claims (8)

In an intake control device for controlling intake air of an internal combustion engine,
In the intake process of the internal combustion engine, the opening degree of the throttle valve provided in the intake system of the internal combustion engine is changed to either the opening direction or the closing direction, and the opening degree of the throttle valve is initialized after the intake process. An air intake control device comprising a control unit that performs the operation. The controller is
In the intake step, the opening degree of the throttle valve is changed in a closing direction, and the opening degree of the throttle valve is returned to the original state after the intake step and before the start of the next intake step. The intake control device according to claim 1. The controller is
With the intake valve open, the opening of the throttle valve is changed in the closing direction, and with the intake valve closed, before the start of the next intake process, the opening of the throttle valve is changed to the original value. The intake control device according to claim 2, wherein the intake control device is returned to a state. The controller is
The intake control device according to claim 2 or 3, wherein, in the intake step, the opening of the throttle valve is changed in a closing direction by a return spring. The controller is
The opening degree of the throttle valve is returned to the original state by the actuator in a period after the intake process and before the start of the next intake process, according to any one of claims 2 to 4. Intake control device. The controller is
In the intake step, the opening degree of the throttle valve is changed in the opening direction, and the opening degree of the throttle valve is returned to the original state after the intake step and before the start of the next intake step. The intake control device according to claim 1. The controller is
While the intake valve is open, the opening of the throttle valve is changed in the opening direction, and when the intake valve is closed, the opening of the throttle valve is changed to the original value before the start of the next intake process. The intake control device according to claim 6, wherein the intake control device is returned to a state. In an intake control method for controlling intake air of an internal combustion engine,
In the intake process of the internal combustion engine, the opening degree of the throttle valve provided in the intake system of the internal combustion engine is changed to either the opening direction or the closing direction, and the opening degree of the throttle valve is initialized after the intake process. An intake control method characterized by:

Images