JP2007138899A - Intake passage structure of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an intake passage structure of an internal combustion engine capable of further suitably varying the flow, flow rate and the flowing direction of intake air. <P>SOLUTION: An intake passage is formed as a double structure of an outside intake passage A and an inside intake passage B in the intake passage, and has a movable pipe 1 having an abutting part abutting on an upstream side end part of an intake manifold 11 in the upstream side end part and opening and closing the intake passage A by the abutting part. The movable pipe 1 extends up to the vicinity of an intake valve 56 possessed by the internal combustion engine 50, and does not contact with the intake manifold 11 except for the abutting part. The upstream side end part of the intake manifold 11 projects in a surge tank 12. The abutting part of the movable pipe 1 and the upstream side end part of the intake manifold 11 mutually abut in the surge tank 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an intake passage structure for an internal combustion engine, and more particularly to an intake passage structure for an internal combustion engine that can change the flow rate, flow velocity, and flow direction of intake air.

  In an internal combustion engine, in order to obtain a more preferable combustion state, a technique for changing the flow rate, flow velocity, flow direction, and the like of intake air has been proposed. In such a technique, an example in which the intake passage is made into a double structure and an example in which a movable portion in which another intake passage is formed in the intake passage are provided are disclosed. For example, Patent Document 1 proposes the following engine control device.

  The engine control device proposed by Patent Document 1 (hereinafter simply referred to as the control device of Patent Document 1) is formed of a fixed portion of an intake pipe and a movable portion slidably accommodated in the fixed portion. The length of the intake pipe is changed by a slide variable mechanism to change the intake charge amount of the engine to obtain a desired engine operating state.

  Patent Document 2 proposes a diesel engine (hereinafter simply referred to as the diesel engine of Patent Document 2) provided with an intake port injector as described below. The diesel engine of Patent Document 2 has an inner port pipe in which the intake port of each cylinder has an inner / outer dual structure in the intake port, and the inner port pipe has a through hole communicating with the inside and outside of the intake port injector. It is formed in at least a part of the part where the fuel injected from the fuel collides.

  In the diesel engine of Patent Document 2 having the above-described inner port pipe, when the intake port injector injects fuel into the inner port pipe, the intake flow control valve provided in the inner port pipe upstream of the intake port injector is closed. Control to the side. As a result, the pressure inside the inner port pipe becomes lower than the pressure outside the inner port pipe, so that the intake air flowing outside the inner port pipe flows into the inner port pipe through the through hole. According to the diesel engine of Patent Document 2, the intake air flowing in through the through hole is used to suppress the injected fuel from adhering to the inner wall surface of the inner port pipe, and further, the liquid fuel is transferred to the inner wall surface. It is possible to prevent the air from flowing into the cylinder and adhering to the bore wall surface.

  Patent Document 3 proposes an intake device for an internal combustion engine shown below (hereinafter simply referred to as the intake device of Patent Document 3). The intake device disclosed in Patent Document 3 has a double intake passage structure composed of a main intake passage and a sub intake passage arranged in close contact with a low wall in the main intake passage, and intake air is introduced into the cylinder through the intake passage. is doing. The downstream end of the auxiliary intake passage is located in a portion of the vicinity of the intake valve opening on the side opposite to the exhaust valve, and an open / close valve is disposed in the auxiliary intake passage. When this on-off valve is closed, the intake air flows only through the main intake passage, and the intake air displaced toward the center of the cylinder in the main intake passage flows in the cylinder axis direction.

  According to the intake device of Patent Document 3 that introduces intake air into the cylinder through the intake passage described above, the combustion state can be improved by reliably generating a tumble flow by closing the on-off valve in the low intake amount operation region of the internal combustion engine. At the same time, the so-called tuning point at which the intake air amount increases due to inertial supercharging can be switched in two stages by opening and closing the on-off valve, while increasing the installation space can be suppressed.

JP-A-6-241051 JP 2005-120978 A Japanese Patent Laid-Open No. 10-274045

  Here, the intake device of Patent Document 1 includes the movable portion as described above. However, the intake device according to the present invention, which will be described later, is provided with a movable portion in order to change the intake pipe length by changing the intake pipe length. Different philosophy. Moreover, although the diesel engine of patent document 2 is equipped with the above inner port pipes, in order to suppress adhesion of the injected fuel, it has a technical idea with the present invention to be described later. Different.

  On the other hand, the intake device of Patent Document 3 uses a double-structured intake passage composed of a main intake passage and a sub-intake passage in order to make the flow rate, flow velocity and flow direction of intake air variable. The technical idea of the present invention is the same. However, in the intake device of Patent Document 3, since the on / off valve is disposed in the auxiliary intake passage, the intake valve fills the intake air by the amount that the on / off valve hinders intake air flowing through the auxiliary intake passage and increases the flow resistance. There is a risk that the efficiency may decrease. Further, in the intake device of Patent Document 3, since the wall surface of the intake passage other than the wall surface defining the main intake passage and the sub intake passage is formed by the cylinder head of the internal combustion engine, the intake air is sucked from the cylinder head by radiation and heat transfer. There is a risk that heat is directly transferred to the air and that the intake charge efficiency is reduced accordingly.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide an intake passage structure for an internal combustion engine that can change the flow rate, flow velocity, and flow direction of intake air more preferably.

  In order to solve the above-mentioned problems, the present invention has a structure in which the intake passage is double-structured inside and outside, and has a contact portion that contacts the wall portion of the intake passage, and is double-structured at the corresponding contact portion. A movable pipe for opening and closing an outer intake passage among the intake passages is provided. According to the present invention, the state in which the intake air is circulated only in the inner intake passage while the outer intake passage is blocked, and the intake air is circulated in both the inner and outer intake passages in the state in which the outer intake passage is opened. Thus, the flow rate, flow velocity and flow direction of intake air can be made variable. Furthermore, according to the present invention, which switches between these two states by the operation of the movable pipe, no intake control valve is provided in the intake passage, so that a reduction in intake charging efficiency is suppressed compared to the case where a valve is provided. Is possible.

  In the present invention, the movable tube may extend to the vicinity of an intake valve included in the internal combustion engine. Here, the intake air flows only through the inner intake passage in a state where the outer intake passage is blocked. In this state, since the intake passage is narrowed, the intake flow velocity is increased. According to the present invention, it is possible to guide the intake air to the combustion chamber while the intake air flow velocity is high. Thereby, by turning the movable tube in an appropriate direction, it is possible to generate a swirling airflow such as a tumble flow or a swirl flow with high strength in a state where the outer intake passage is blocked.

  In the present invention, the movable tube may not contact the wall portion of the intake passage except for the contact portion. According to the present invention, it is possible to suppress the direct transfer of heat from the cylinder head to the intake air flowing through the inner intake passage other than the abutting portion, thereby significantly reducing the intake air temperature. As a result, the occurrence of knocking in the internal combustion engine can be suppressed, and the intake air charging efficiency can be improved by reducing the intake air temperature.

  In the present invention, the contact portion may be formed at an upstream end portion of the movable pipe, and may contact an upstream end portion of the wall portion of the intake passage. For example, as in the present invention, it is possible to form a contact portion and contact the wall portion of the intake passage.

  Further, according to the present invention, the intake passage may communicate with the intake storage means on the upstream side, and the contact portion and the wall portion of the intake passage may contact with each other within the intake storage means. For example, as in the present invention, the contact portion and the wall portion of the intake passage can be contacted.

  ADVANTAGE OF THE INVENTION According to this invention, the intake passage structure of the internal combustion engine which can make the flow volume, flow velocity, and distribution direction of intake air more variable can be provided more suitably.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an intake manifold that is a main configuration of an internal combustion engine 50 and an intake system of the internal combustion engine 50 to which the configuration of an intake passage structure (hereinafter simply referred to as an intake passage structure) 100 of an internal combustion engine according to the present embodiment is applied. 11 is a view showing together with a surge tank (intake storage means) 12. FIG. 1A shows the above-described configuration with the outer intake passage A opened, and FIG. 1B shows the above-described configuration with the intake passage A blocked. Yes.

  Although the internal combustion engine 50 shown in this embodiment is a direct injection gasoline engine, the intake control device 100 according to this embodiment can be applied to a so-called lean burn engine, for example. Other internal combustion engines and other gasoline engines or diesel engines can be used as long as the intake flow rate, flow rate, and flow direction can be changed to improve the mixing and flame propagation characteristics of the air-fuel mixture and improve the output. The intake control device 100 according to the present embodiment can also be applied to the above. Further, the number of cylinders and the arrangement of the cylinders of the internal combustion engine 50 are not particularly limited, and may be, for example, an in-line four cylinder or a V-type six cylinder.

  As shown in FIG. 1, the combustion chamber 51 is formed as a space surrounded by a cylinder head 52, a cylinder block 53, and a piston 54. An intake port 55 communicates with the combustion chamber 51. The intake port 55 is configured to guide intake air to the combustion chamber 51, and the intake port 55 is formed in the cylinder head 52. The cylinder head 52 is provided with an intake valve 56. The intake valve 56 is configured to open and close the flow path of the intake port 55 to allow intake air to flow into the combustion chamber 51 and to block supply of intake air to the combustion chamber 51. The cylinder head 52 is formed with an exhaust port 57 that is configured to exhaust the exhaust gas from the combustion chamber 51, and an exhaust valve 58 that is configured to open and close the flow path of the exhaust port 57. It is arranged.

  An intake manifold 11 is connected to an inlet portion of the intake port 55 of the cylinder head 52. The intake manifold 11 has independent flow paths corresponding to the intake ports 55 and other intake ports (not shown), and communicates each intake port including the intake ports 55 with the surge tank 12. It is a configuration. In this embodiment, the intake manifold 11 and each intake port including the intake port 55 form an intake passage, and the intake manifold 11 and each intake port including the intake port 55 form a wall portion of each intake passage. Have. In the present embodiment, the intake passage structure 100 is typically shown as an intake passage formed by the intake port 55 and the intake manifold 11, but each intake passage formed by the other intake ports and the intake manifold 11 is shown. Also, a structure similar to the intake passage structure 100 can be applied.

  The surge tank 12 has a configuration for collecting intake air therein and preventing pulsation and interference of the intake air. In this embodiment, the upstream end portion of the intake manifold 11 is projected into the surge tank 12, and the upper surface of the upstream end portion is formed in a funnel shape.

  The movable pipe 1 is a substantially cylindrical member made of resin, and the intake passage formed by the intake manifold 11 and the intake port 55 has an internal / external double structure of the intake passage A and the intake passage B, and the intake passage B It is the structure for opening and closing. The movable tube 1 extends to the vicinity of the intake valve 56, and a contact portion that contacts the upstream end portion of the intake manifold 11 is formed at the upstream end portion of the movable tube 1. Further, the movable tube 1 is disposed in the approximate center of the intake passage so as not to contact the intake manifold 11 except at the contact portion. The material of the movable tube 1 is not limited to resin, and may be aluminum, for example. However, an actuator provided for driving the movable tube 1 so as to ensure sufficient responsiveness when the movable tube 1 is driven. It is preferable to apply a lightweight material to the movable tube 1 so as to suppress an increase in the size of the drive mechanism such as 2. In view of the shape of the intake passage, ease of manufacture, etc., the movable tube 1 is preferably substantially cylindrical. However, the present invention is not limited to this, and other appropriate structures can be used as long as the intake passage can be formed into a double structure. The shape may also be

  Further, the upstream end of the movable tube 1 is formed as follows so as not to increase the flow path resistance against the intake air flowing into the intake flow path B. FIG. 2 is a flow diagram showing the flow of intake air generated in the surge tank 12 when the upstream end of the intake manifold 11 does not protrude into the surge tank 12 and the movable pipe 1 is not provided. It is. In FIG. 2, an intake manifold that does not project the upstream end to the surge tank 12 is shown as an intake manifold 11X. By forming the upstream end of the movable tube 1 into a funnel shape along the flow line shown in FIG. 2, it is possible to reduce the flow path resistance against the intake air flowing into the intake flow path B. The upper surface of the upstream end of the intake manifold 11 is also formed in a funnel shape so as not to increase the flow resistance of the intake air flowing into the intake flow path A. In this embodiment, the intake passage structure 100 is realized by the intake port 55 and the intake manifold 11 forming the intake passage and the movable pipe 1.

  The actuator 2 is configured to drive the movable tube 1 based on the control of an electronic control unit (ECU) 3. For example, an electric motor can be applied to the actuator 2. The actuator 2 drives the movable tube 1 to the position shown in FIG. This position is a position where the maximum intake flow rate required by the internal combustion engine 50 can be secured, and a position where the contact portion of the movable pipe 1 can be prevented from being a flow path resistance against the intake air flowing into the intake passage A. It is. In this state, the intake passage A is opened. Further, the actuator 2 drives the movable tube 1 to the position shown in FIG. This position is a position where the contact portion of the movable tube 1 contacts the upstream end portion of the intake manifold 11. In this state, the intake passage A is blocked. A driving mechanism for driving the movable tube 1 by the actuator 2 will be described later with a specific example.

  Next, the intake air behavior in the state shown in FIG. 1 (a) and the state shown in FIG. 1 (b) and an example of switching between these states will be described in detail. In the state shown in FIG. 1A, since the intake passage A is opened, the intake air flows through the intake passages A and B and is supplied from the surge tank 12 to the combustion chamber 51. Thereby, it is possible to increase the flow rate of the intake air supplied to the internal combustion engine 50 as compared with the state shown in FIG. Therefore, for example, when the internal combustion engine 50 has a high rotation speed or a high load, it is possible to secure the intake air flow rate required by the internal combustion engine 50 by switching to the state shown in FIG.

  On the other hand, since the intake passage A is blocked in the state shown in FIG. 1B, the intake air flows only through the intake passage B and is supplied from the surge tank 12 to the combustion chamber 51. In this state, since the intake passage is narrow, it is possible to increase the flow velocity of the intake air instead of decreasing the intake air flow rate as compared with the state shown in FIG. In this state, since the movable pipe 1 extends to the vicinity of the intake valve 56, it is possible to supply intake air to the combustion chamber 51 while maintaining the magnitude of the flow velocity. Therefore, for example, when the internal combustion engine 50 has a low rotation and a low load, a swirling air flow such as a tumble flow or a swirl flow is generated in the combustion chamber 51 with high strength by switching to the state shown in FIG. It is possible. In the present embodiment, since the movable pipe 1 extends toward the wall surface on the exhaust valve 58 side of the wall surface of the combustion chamber 51, the intake air that has flowed through the intake passage B in the state shown in FIG. In the combustion chamber 51, the direction is changed by the wall surface of the combustion chamber 51 on the exhaust valve 58 side, the crown surface of the piston 54, and the wall surface of the combustion chamber 51 on the intake valve 56 side, and is generated in a strong tumble flow.

  In the state shown in FIG. 1B, an air layer is formed between the wall surface of the intake port 55 formed in the cylinder head 52 and the movable pipe 1 (closed intake passage A). Because this air layer can significantly reduce the heat transmitted from the cylinder head 52 to the intake air flowing through the intake passage B, that is, the intake air temperature can be significantly reduced, as shown in FIG. In this state, the occurrence of knocking in the internal combustion engine 50 can be suppressed, and the intake air charging efficiency can be improved by reducing the intake air temperature.

  Next, a specific example of a driving mechanism for driving the movable tube 1 with the actuator 2 will be described in detail with reference to FIGS. 3, 4, and 5. FIG. 3 is a view showing a first specific example of a drive mechanism for driving the movable tube 1. FIG. 3A shows the first specific example with the intake passage A opened, and FIG. 3B shows the first specific example with the intake passage A blocked. Show. A drive mechanism for driving the movable tube 1 by the actuator 2 can be realized by a link mechanism as shown in FIG. 3, for example. This link mechanism includes a link 5 and a fixed pin 6. When this link mechanism is adopted, a guide 7 for supporting the movable tube 1 on the outer peripheral surface is press-fitted into the intake passage. For example, an actuator such as a stepping motor can be applied to the actuator 2, and this is the same for the second specific example and the third specific example described later.

  The link 5 is fixed to the rotating shaft 2a of the actuator 2 at one end. However, the rotary shaft 2a may not be the output shaft itself of the actuator 2. A long hole 5a as shown by an arrow C is formed in the link 5, and a fixing pin 6 is slidably disposed in the long hole 5a. The fixed pin 6 is further fixed to the upstream end of the movable tube 1. If the above-described link mechanism is employed as the drive mechanism, the movable tube 1 can be slid along the guide 7 by rotating the link 5 by the actuator 2, and as a result, FIG. And it is possible to open and close the intake passage A as shown in (b).

  Next, a second specific example of the drive mechanism will be described in detail with reference to FIG. The drive mechanism can also be realized by a rack and pinion system as shown in FIG. In this case, the rack gear 8 is fixed to the upstream end of the movable tube 1 with the extending direction of the rack gear 8 oriented in a direction parallel to the direction in which the movable tube 1 is to be driven. Further, the pinion gear 9 is disposed so as to correspond to the rack gear 8. Further, the rotation shaft 2 a of the actuator 2 is coupled to the rotation center of the pinion gear 9. If the drive mechanism is of the rack and pinion system described above, the movable pipe 1 can be driven to open and close the intake passage A by rotating the pinion gear 9 by the actuator 2.

  Next, a third specific example of the drive mechanism will be described in detail with reference to FIG. Here, FIG. 5A shows the third specific example with the intake passage A opened, and FIG. 5B shows the third specific example with the intake passage A blocked. It is shown in the state. The drive mechanism can be realized by a rigid support member 10 as shown in FIG. 5, for example. In this case, the end of the upstream side of the movable tube 1 and the rotary shaft 2a of the actuator 2 are coupled by the rigid support member 10 so that the movable tube 1 opens the intake passage A at the position shown in FIG. .

  The actuator 2 drives the movable tube 1 via the rigid support member 10 and blocks the intake passage A in a state where the movable tube 1 is inclined as shown in FIG. The drive mechanism shown as the third specific example can be employed as a simple drive mechanism when the inclination of the movable tube 1 can be tolerated to some extent, as well as the state shown in FIG. 5 (a) and the state shown in FIG. 5 (b). Thus, it is possible to adopt it when it is desired to change the flow direction of the intake air flowing through the intake passage B intentionally. As described above, the intake passage structure 100 that can change the flow rate, flow rate, and flow direction of intake air more preferably can be realized.

  The embodiment described above is a preferred embodiment of the present invention. However, the present invention is not limited to this, and various modifications can be made without departing from the scope of the present invention.

1 is a view showing a configuration of an intake passage structure 100 according to the present embodiment together with an internal combustion engine 50 to be applied and an intake manifold 11 and a surge tank 12 which are main components of an intake system of the internal combustion engine 50. FIG. FIG. 4 is a diagram showing the flow of intake air generated in the surge tank 12 with flow lines when the upstream end of the intake manifold 11 is not protruded into the surge tank 12 and the movable pipe 1 is not disposed. It is a figure which shows the 1st specific example of the drive mechanism for driving the movable tube. It is a figure which shows the 2nd specific example of the drive mechanism for driving the movable tube. It is a figure which shows the 3rd specific example of the drive mechanism for driving the movable tube.

Explanation of symbols

1 Movable tube 2 Actuator 3 ECU
5 link 6 fixed pin 7 guide 8 rack gear 9 pinion gear 11 intake manifold 12 surge tank 50 internal combustion engine 51 combustion chamber 52 cylinder head 53 cylinder block 54 piston 55 intake port 56 intake valve 57 exhaust port 58 exhaust valve 100 intake passage structure of the internal combustion engine

Claims (5)

In the intake passage, the intake passage has an inner and outer double structure, and has a contact portion that contacts the wall of the intake passage, and the outer side of the intake passage that is double-structured at the corresponding contact portion. An intake passage structure for an internal combustion engine, comprising a movable pipe for opening and closing the intake passage. The intake passage structure for an internal combustion engine according to claim 1, wherein the movable pipe extends to the vicinity of an intake valve provided in the internal combustion engine. The intake passage structure of an internal combustion engine according to claim 1 or 2, wherein the movable pipe does not contact the wall portion of the intake passage except at the contact portion. The said contact part is formed in the edge part of the upstream of the said movable pipe | tube, and contact | abuts the edge part of the upstream of this wall part among the wall parts of the said intake passage. An intake passage structure for an internal combustion engine according to claim 1. The intake passage communicates with intake storage means upstream,
The intake passage structure for an internal combustion engine according to any one of claims 1 to 4, wherein the contact portion and a wall portion of the intake passage are in contact with each other in the intake storage means.

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