JP4563861B2 - Air intake duct - Google Patents

Description

  The present invention relates to an intake duct, and more particularly, an air flow area of an air flow passage connected to an air intake portion of an engine and defined inside the duct body is increased or decreased according to the rotational speed of the engine. The present invention relates to an intake duct that is changed.

  In recent years, automobiles produced in recent years are equipped with various safety devices such as airbag devices and brake devices, while improving the safety performance by taking measures to increase the rigidity of the body and chassis. Therefore, since the vehicle weight tends to increase inevitably, it is required to increase the output of the engine in order to ensure traveling performance. However, in today, when environmental problems are highlighted, improvement of environmental performance such as improvement of fuel consumption, exhaust gas cleanup, noise reduction, etc. is a major issue, and improvement of output without increasing the displacement is aimed at. Countermeasures are sought after.

  For example, FIG. 7 is an explanatory sectional view showing an air supply part of an engine EG mounted in an engine room 12 of an automobile, and the air required for rotational driving of the engine EG is the front part of the vehicle body 10. The air is taken in from the intake duct D1 assembled to the air cleaner AC and cleaned by the air cleaner AC, and then supplied to the engine EG. In order to improve the output of the engine EG in such a configuration, the air flow resistance of the intake duct D1 that takes in the external air is reduced as much as possible so that the taken-in external air is smoothly supplied to the engine EG. The method is considered effective. Specifically, with the intake duct D1 enlarged, the opening area of the air intake port 22 is increased, and the cross-sectional area (air flow area) of the air flow path defined inside is set to be large. This makes it easier to increase the engine output. However, when the intake duct D1 is increased in size, a new problem that engine noise (particularly combustion noise) radiated from the air intake port 22 to the outside of the vehicle increases.

Therefore, for example, as shown in FIG. 8, a rotary shutter type valve 26 is disposed inside the large duct body 20, and the posture of the valve 26 is displaced to displace the air flow area in the air flow passage 24. An intake duct D1 is proposed in which the air pressure is changed. In the intake duct D1 of this type, when the rotational speed of the engine EG is low during normal driving or the like, the valve 26 is displaced to the first posture indicated by the solid line in FIG. Engine noise radiated from the intake port 22 is suppressed. Further, when the rotational speed of the engine EG increases during acceleration traveling, the valve 26 is rotated and displaced toward the second posture indicated by the two-dot chain line in FIG. The intake of external air is allowed to cope with the high output of the engine EG. An intake duct having such a variable intake structure is disclosed in Patent Document 1, for example.
Japanese Patent Laid-Open No. 11-82202

  By the way, the above-described conventional intake duct D1 is substantially perpendicular to the air flow direction in the air flow passage 24 when the valve 26 is displaced in the above-described first posture, so that the air flow resistance is low. There was a problem that it was extremely deteriorated and sufficient external air could not be taken in. This is because, as shown by a broken line in FIG. 9, air separation largely occurs at the end edge portion of the valve 26, so that a substantial effective air circulation area is reduced. In order to eliminate such an inconvenience, the distance between the end edge of the valve 26 in the first posture and the inner wall surface of the duct may be increased. However, this increases the air circulation area. This makes it impossible to suppress engine noise.

  Therefore, as illustrated in FIG. 10, by adding a bypass path 28 to the duct body 20, the valve 26 is set to the first posture during low rotation so that external air is taken in via the bypass path 28. An intake duct D1 is also proposed in which the valve 26 is set to the second posture during high rotation so that external air is taken in from both the duct body 20 and the bypass passage 28. However, in the case of the intake duct D1 having such a configuration, there is a problem that the manufacturing cost increases due to an increase in the number of parts, and there is a disadvantage that the external size becomes large and a large installation space has to be secured, such as a small car. In some cases, it could not be adopted.

  Further, in the case of the rotary shutter type valve 26 described above, since the rotational displacement amount of the valve 26 and the increase / decrease amount of the air flow area are not proportional, the intake amount of external air cannot be controlled appropriately, The engine output characteristics were also affected. For example, as illustrated in FIG. 11, in the case of a 30 degree posture (denoted by a broken line) rotated by 30 degrees with respect to the valve 26 (shown by a solid line) in the first posture, an increase in the air circulation area with respect to the amount of rotation The amount is slight. However, when the posture is rotated from the 30 degree posture (displayed with a broken line) to the 60 degree posture (displayed with a one-dot chain line), the amount of increase in the air circulation area becomes considerably large. In the case of rotation to (two-dot chain line display), the amount of increase in the air circulation area is doubled at once. Further, when the valve 26 is in the first posture and a posture close thereto, not only the air flow resistance increases as described above, but also the drawback that the air flow is greatly disturbed on the rear side (downstream side) of the valve 26 is pointed out. Is done.

  Accordingly, an object of the present invention is to provide an intake duct that can appropriately control the amount of external air taken in according to the engine speed and can reduce the manufacturing cost.

In order to solve the above-mentioned problems and achieve the intended purpose, the invention according to claim 1 of the present application,
In the intake duct connected to the air intake portion of the engine, the air flow area of the air flow passage defined inside the duct body is increased or decreased according to the rotational speed of the engine.
An air circulation port formed in a required portion of the air flow passage;
A valve installation portion provided in the air flow passage on the downstream side of the air circulation port ;
The valve installation portion slides along the air flow direction can be disposed, a valve body side has been directed to the air flow port is bulged substantially cone shape,
The valve installation portion is disposed on the downstream side of the valve body, and is always composed of a biasing member that elastically biases the valve body toward the air circulation port side,
The valve installation portion includes a first sliding guide portion in which a rod extending downstream from the valve body is slidably aligned, and a downstream side of the first sliding guide portion along the air flow direction. And a second sliding guide portion slidably aligned with a stopper formed in a diameter larger than the rod at a downstream end of the rod,
The valve body which is supported on the valve installation body by said rod and stopper, during low rotation of the engine, the air flow port proximate to by Ri before Symbol vent port to the biasing force of the biasing member the air flow area to minimize, during rotation rise of the engine, from said duct SL before Ri by the pressure of the air taken into the body vent port spaced downstream, the air flow of the air flow port It is configured to increase the area.

Therefore, according to the first aspect of the present invention, the valve body disposed in the valve installation portion slides in the air circulation direction according to the engine speed, so that the air circulation area is reduced at the time of low rotation. Engine noise can be prevented from being radiated to the outside, and sufficient air can be supplied to the engine by increasing the air flow area at high revolutions. In the valve body, since the rod is supported by the first sliding guide portion and the stopper is supported by the second sliding guide portion, the posture of the valve body that slides does not change, and the air flow It is possible to prevent inconveniences such as disturbance of the air flow flowing through the road. In addition , since the valve body has a substantially cone shape that bulges toward the air flow port side, the air flow resistance is greatly improved, and there is no need to provide a bypass path like a conventional intake duct, reducing manufacturing costs and assembly. The installation space can be reduced by facilitating work and downsizing.

According to a second aspect of the present invention, in the first aspect of the invention, the stopper is in contact with the upstream end of the second sliding guide portion to minimize the air flow area of the air flow port. The gist is to regulate the displacement of the valve body to the upstream side in the air flow direction . Therefore, according to the second aspect of the present invention, the stopper is in contact with the upstream end of the second sliding guide portion, so that the valve body is properly maintained in a state where the air flow area of the air flow port is minimized. Is done.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the urging force of the urging member stops and holds the valve body at a position closest to the air circulation port when the engine is running at a low speed. The gist of the invention is that the valve body is set to a size that allows the valve body to move away from the air circulation port to the downstream side as the rotation of the engine increases. Therefore, according to the third aspect of the present invention, the sliding movement of the valve body is performed based on the balance between the taken-in external air pressure and the urging force of the urging member. It is not particularly necessary, and the whole can be made compact and the product cost can be prevented from increasing.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the sliding movement amount of the valve body and the accompanying increase / decrease amount of the air circulation area of the air circulation port are substantially proportional. The gist is that the relationship is set. Therefore, according to the fourth aspect of the invention, the engine speed and output directly increase, and ideal engine output characteristics can be obtained.

  According to the intake duct according to the present invention, it is possible to appropriately control the amount of external air taken in according to the engine speed, and to achieve a beneficial effect such as reduction in manufacturing cost.

  Next, an intake duct according to the present invention will be described below with reference to the accompanying drawings by way of preferred embodiments.

  1 is a cross-sectional view showing an intake duct according to a preferred embodiment in a state where an air flow area is minimized by a valve body, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, and FIG. It is sectional drawing of the intake duct shown in the state which made the air | flow distribution area the maximum by. As in the case of FIG. 7, the intake duct D of the present embodiment is assembled to the front side of the engine room 12 in the front portion of the vehicle body 10, and directs the air intake port 33 in the forward direction of the vehicle body 10, while The rear end portion is connected to an air cleaner AC disposed in the air intake portion of the EG, and then provided for implementation. For convenience of explanation, the left side of FIG. 1 is the front side of the intake duct, and the right side of the drawing is the rear side of the intake duct.

  The intake duct D of the present embodiment is located on the downstream side of the air circulation port 50 in the duct body 30 and is slidably movable along the air circulation direction. The valve body 60 is provided, and a compression spring 70 that constantly urges the valve body 60 toward the air circulation port 50 side. Then, the valve body 60 slides along the air flow direction due to the balance between the pressure of the air taken in as the engine EG rotates and the urging force of the compression spring 70, and the air in the air flow port 50 The distribution area S is changed. According to such a configuration, it is possible to prevent the air circulation area S from decreasing when the engine EG is rotating at a low speed and radiating the engine noise to the outside, and to increase the air circulation area S when the engine EG is rotating at a high speed. Sufficient air can be supplied to the engine EG.

  The duct main body 30 that forms the main body of the intake duct D of this embodiment includes a duct member 32 that is connected and fixed to the air cleaner AC, and an air intake member 34 that is attached to the front side of the duct member 32. The duct member 32 is a synthetic resin molding material made of high-density polyethylene or the like. As illustrated in FIGS. 1 and 2, the duct member 32 has a cylindrical shape by opposingly joining the two half-shaped halves 32A and 32A. None, the front part from the front end part to the required length has a larger diameter than the rear part behind it. As will be described later, the large-diameter portion accommodates the valve installation portion 40 of the air intake member 34. An installation opening 36 for the air intake member 34 is formed in a sleeve shape on the front end face, and an air outlet 35 connected to the air cleaner AC is opened on the rear end face.

  The air intake member 34 is a synthetic resin molding material made of high-density polyethylene or the like, and has a so-called funnel shape in which the front air intake port 33 expands toward the tip as illustrated in FIG. The air intake tube portion 38 and a valve installation portion 40 integrally connected to the rear side of the air intake tube portion 38 are configured. The valve installation part 40 is set to an outer diameter dimension that allows the insertion into the duct member 32 through the installation opening 36 described above. Thus, the air intake member 34 is attached and fixed to the front side of the duct member 32 in a state where the valve installation portion 40 is inserted into the duct member 32 and the air intake tube portion 38 extends forward. In addition, a rib 42 extending in the circumferential direction is provided on the outer surface of the air intake member 34, and the rib 42 abuts against the opening end surface of the installation opening 36, thereby preventing the duct member 32. The air intake member 34 is positioned. The air intake member 34 is fixed to the duct member 32 by appropriate fixing means such as a screw (not shown).

  As illustrated in FIGS. 4 and 5, the valve installation portion 40 has a front portion serving as a valve storage space 44 communicating with the air intake tube portion 38 described above, and stores a valve body 60 described later. On the rear side of the storage space 44, there are slide guide portions 46 and 48 for supporting the valve body 60 so as to be slidable. A boundary portion between the air intake tube portion 38 and the valve installation portion 40, that is, a front end portion of the valve storage space 44 is an air circulation port 50, and a total of four outer wall portions corresponding to the valve storage space 44 are provided. The opening 52 is opened in the circumferential direction. Thus, an air flow passage 54 is defined from the inside of the air intake cylinder portion 38 to the inside of the duct member 32 via the air circulation port 50 and the respective openings 52 described above.

  The valve body 60 has an outer diameter size that can be installed in the valve storage space 44 described above, and has a substantially cone shape in which the front side facing the air circulation port 50 is expanded, and the outer diameter dimension of the maximum outer shape portion thereof. Is set to be substantially the same as or slightly smaller than the inner diameter of the air circulation port 50. A rod 62 inserted into the small-diameter sliding guide 46 is disposed at the rear end of the valve body 60, and is slid onto the large-diameter sliding guide 48 at the tip of the rod 62. The stopper 64 which contacts is fixed. Therefore, the valve body 60 is allowed to slide along the air flow direction in the valve storage space 44 because the rod 62 and the stopper 64 are in sliding contact with the respective sliding guide portions 46 and 48. In addition, the above-mentioned “cone shape” defined by the present application is a shape in which the outer diameter dimension gradually decreases toward the tip side, such as a conical shape, a truncated cone shape, an umbrella shape, etc. in addition to the bullet shape illustrated in each figure. It is assumed that the shape is such that all can be contained and an increase in air flow resistance against the external air taken in can be suppressed as low as possible.

  Here, in the most advanced state of the valve body 60 in which the stopper 64 is in contact with the front end surface of the sliding guide portion 48, the front bulge portion of the valve body 60 is connected to the air circulation port 50 as illustrated in FIG. 1. The air flow area S defined between the valve body 60 and the air flow port 50 is set to be minimum (S1) by appropriately entering. That is, when the valve body 60 is moved forward most, the outer surface of the valve body 60 is positioned at the edge of the air circulation port 50 with a slight gap, as schematically shown in FIG. A minimum necessary air flow area S (S1) that allows the intake of air required when the engine EG is running at a low speed is ensured.

  In addition, since the front side of the valve body 60 bulges into a bullet shape, the external air taken into the air intake member 34 via the air intake port 33 is applied to the front side bulge surface of the valve body 60. Simultaneously with the collision, it spreads smoothly and radially along the bulging surface, and flows into the duct member 32 through the air circulation port 50 and each opening 52. Therefore, even if the minimum air flow area S1 is considerably smaller than that of the conventional intake duct D1 illustrated in FIG. 8 and the like, the air required for the engine EG can be taken in. For this reason, since the air circulation area S is minimized, the shielding performance against engine noise is improved, and engine noise radiated to the outside through the air intake port 33 is reduced.

  On the other hand, in the last retracted state of the valve body 60 in which the valve body 60 is in contact with the rear end surface of the valve storage space 44, the valve body 60 is almost completely removed from the air circulation port 50 as illustrated in FIG. Thus, the air flow area S defined between the valve body 60 and the air flow port 50 is set to be the maximum (S2). When the valve body 60 is finally retracted, the stopper 64 is prevented from being removed from the sliding guide portion 48, and is necessary when the engine EG is rotating at high speed, as schematically shown in FIG. 6 (b). The air circulation area S (S2) that allows the intake of air is secured.

  In addition, since the valve body 60 bulges forward in the shape of a bullet, external air taken into the air intake member 34 via the air intake port 33 enters the front bulge surface of the valve body 60. Simultaneously with the collision, it spreads smoothly and radially along the bulging surface, and flows into the duct member 32 through the air circulation port 50 and each opening 52. Then, since the posture of the duct body 60 does not change when sliding backward, the taken-in external air stably flows into the large-diameter portion of the duct member 32, and in the duct member 32 Air turbulence is prevented from occurring.

Further, the rod 62 described above is engaged with the valve body 60 and the valve installation portion 40 (duct body 30), and is always a compression spring (attached) that elastically biases the valve body 60 toward the air circulation port 50 side. Force member) 70 is attached. The urging force of the compression spring 70 is such that (1) the valve body 60 can be stopped and held at a position closest to the air circulation port 50 ( most advanced state) when the engine EG is rotating at a low speed. The valve body 60 is set to a size that allows the valve body 60 to move away from the air circulation port 50 as the engine EG rotates. That is, the valve body 60 is slid back and forth so as to follow the rotational speed of the engine EG according to the balance relationship between the pressure of the air taken in by the rotational drive of the engine EG and the urging force of the compression spring 70. The air flow area S at the air flow port 50 can be changed.

  As a result, when the engine EG is in a low rotation including an idling state, the urging force of the compression spring 70 is greater than the pressure of the taken-in external air. The air flow area S of the air flow port 50 becomes the minimum S1. Thereby, the engine noise (combustion sound etc.) radiated | emitted outside via the air intake 33 is reduced suitably.

  On the other hand, when the rotation of the engine EG is increased, the pressure of the external air taken in becomes greater than the urging force of the compression spring 70, so that the valve body 60 moves from the air circulation port 50 against the urging force of the compression spring 70. It moves away to the rear side and increases the air flow area S of the air flow port 50. Moreover, since the pressure of the external air taken in increases as the engine speed increases, the amount of sliding movement of the valve body 60 increases and the air circulation area S increases. In the structure illustrated in the embodiment, the sliding movement amount of the valve body 60 and the accompanying increase / decrease amount of the air circulation area S of the air circulation port 50 are set to have a substantially proportional relationship.

  In the intake duct D of the embodiment, in the air flow passage 54, the cross-sectional area (air flow area) Sa at the point P 1 in the air intake cylinder portion 38 and the break at the point P 2 in the large diameter portion of the duct member 32. The area (air flow area) Sb is set to be substantially the same or larger. The air flow area S (S2) at the air flow port 50 when the valve body 60 is finally retracted is set to be substantially the same as the above-described cross-sectional areas Sa and Sb. As a result, when the valve body 60 is finally retracted, the cross-sectional area of the air flow passage 54 is substantially constant at any point, and smooth circulation of the taken-in external air is realized.

  According to the intake duct D of the present embodiment described above, the following effects can be obtained. First, since the valve body 60 slides in accordance with the rotational speed of the engine EG, the air flow area S is reduced during low rotation to prevent the engine noise from being radiated to the outside, and the air flow area S during high rotation. Sufficient air can be supplied to the engine EG. And since the valve body 60 is exhibiting the substantially cone shape which bulged to the air circulation port 50 side, air circulation resistance is improved greatly, and it is necessary to provide the bypass path 28 like the conventional intake duct D1 illustrated in FIG. Therefore, the manufacturing cost can be reduced, the assembly work can be facilitated, and the installation space can be reduced by downsizing. Therefore, since the air circulation area S at the time of low rotation can be reduced, radiation of the engine sound from the air intake port 33 at the time of low rotation can be suppressed low, and a resonator having a large volume becomes unnecessary.

  Further, when the valve body 60 slides along the air flow direction of the air flow passage 54, the posture does not change with respect to the flow of the taken-in external air. Disturbances can be suitably prevented. Further, the sliding movement of the valve body 60 is performed based on the balance relationship between the pressure of the taken-in external air and the urging force of the compression spring 70, so that no separate drive mechanism or the like is required, and the whole is compact. In addition, the product cost is prevented from increasing. Furthermore, the amount of slide movement of the valve body 60 and the accompanying increase / decrease amount of the air flow area S of the air flow port 50 are set to have a substantially proportional relationship. Thus, an ideal engine output characteristic can be obtained.

  In addition, when installing in the vehicle type from which a body shape and size differ, it is sufficient to change only the duct member 32 into another duct member from which a size and a shape differ, and the air intake member 34 and the valve body 60 attached to this. Can be used in common, and the cost reduction effect due to the common use of parts is further enhanced.

  Since the intake duct according to the present invention is mounted on an air intake portion of an engine and used for implementation, it can be widely implemented in various automobiles and other industrial machines equipped with the engine.

Sectional drawing which showed the air intake duct which concerns on a suitable Example in the state which made the air | flow distribution area the minimum with the valve body. II-II sectional view taken on the line of FIG. Sectional drawing which showed the air intake duct illustrated in FIG. 1 in the state which maximized the air circulation area with the valve body. The partial perspective view which showed the main part of the air intake duct partly broken. The exploded perspective view of an air intake member, a valve body, and a compression spring. Explanatory drawing which showed schematically the minimum state and the maximum state of an air circulation area. 1 is a side sectional view of a vehicle showing a front side portion of a vehicle body with an intake duct assembled thereto. Explanatory drawing which illustrated schematically the variable structure of the air circulation area in the conventional intake duct. Explanatory drawing which showed the problem of the air intake duct illustrated in FIG. Explanatory sectional drawing which showed the structure of the intake duct currently implemented. FIG. 9 is an explanatory diagram showing still another problem of the intake duct exemplified in FIG. 8.

Explanation of symbols

30 Duct body, 40 Valve installation section, 44 Valve storage space
46 Sliding guide part with a small diameter (first sliding guide part), 48 Sliding guide part with a large diameter (second sliding guide part)
50 air flow port, 54 air flow passage, 60 valve body, 62 rod, 64 stopper 70 compression spring (biasing member), EG engine, S air flow area

Claims (4)

The air flow area (S) of the air flow passage (54) connected to the air intake portion of the engine (EG) and defined in the duct body (30) is determined according to the rotational speed of the engine (EG). In the intake duct that is changed by
An air circulation port (50) formed in a required portion of the air flow passageway (54), and
A valve installation part (40) provided in the air flow passage (54) on the downstream side of the air circulation port (50) ;
A valve body (60) in which the valve installation part (40) is arranged so as to be slidable along the air flow direction, and the side facing the air flow port (50) is bulged into a substantially cone shape,
An urging member (70) disposed downstream of the valve body (60) in the valve installation portion (40) and constantly urging the valve body (60) toward the air circulation port (50). And consist of
The valve installation part (40) includes a first sliding guide part (46) in which a rod (62) extending downstream from the valve body (60) is slidably aligned, and the first sliding part. A stopper (linearly extending along the air flow direction on the downstream side of the guide portion (46), and formed on the downstream end of the rod (62) with a larger diameter than the rod (62) ( 64) comprises a second sliding guide (48) slidably aligned,
The valve body (60) supported by the valve installation body (40) by the rod (62) and the stopper (64) is attached to the biasing member (70) when the engine (EG) is rotated at a low speed. air flow port air flow area of the (50) (S) and the minimum is close to I Ri before Symbol vent port to force (50), during rotation rise of the engine (EG), the duct body (30 ) by the pressure of the incorporated air to intake into the Ri before Symbol vent port from (50) spaced downstream, by being configured so as to increase the air flow area (S) of the air flow port (50) Intake duct characterized by. The stopper (64) is in contact with the upstream end of the second sliding guide portion (48), so that the valve body in a state where the air flow area (S) of the air flow port (50) is minimized. The intake duct according to claim 1 , wherein displacement of (60) upstream in the air flow direction is restricted . The urging force of the urging member (70) is large enough to stop and hold the valve body (60) at a position closest to the air circulation port (50) when the engine (EG) is rotated at a low speed. The size is set to allow the valve body (60) to move away from the air circulation port (50) to the downstream side as the rotation of the engine (EG) increases. Intake duct. The sliding movement amount of the valve body (60) and the accompanying increase / decrease amount of the air circulation area (S) of the air circulation port (50) are set to have a substantially proportional relationship. The intake duct according to any one of the above.

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