JP5751533B2 - Intake device - Google Patents

Description

  The present invention relates to an intake device that includes an air cleaner that purifies intake air (hereinafter referred to as intake air) sucked into an internal combustion engine, and an intake air amount measurement device that measures an intake air amount discharged from the air cleaner.

  2. Description of the Related Art Conventionally, an intake device in which an intake air amount measuring device is attached to a duct connected to an intake outlet of a cleaner case of an air cleaner is well known (see, for example, Patent Documents 1 and 2). In addition, as an intake air amount measurement device, a device including a bypass flow path for taking in a part of intake air and a flow rate sensor arranged in the bypass flow path is well known.

  In the intake devices shown in Patent Document 1 and Patent Document 2, a bent portion that changes the direction of intake air is formed between the cleaner case and the duct. That is, the flow direction in the cleaner case and the flow direction in the duct intersect, and the intake air from the cleaner case flows into the duct while bending near the intake outlet. For this reason, a biased velocity distribution is generated in the duct such that the flow velocity is small inside the bend and the flow velocity is large outside the bend.

JP-A-9-88658 JP-A-11-212528

By the way, when the flow rate is measured by the intake air amount measurement device, if the flow velocity near the inlet and outlet of the bypass flow path is small, the flow is difficult to stabilize and it is difficult to measure the flow rate with high accuracy.
Therefore, it is required to arrange at least one of the inlet and the outlet of the bypass channel at a position where the flow velocity is large.

Therefore, in Patent Document 1, the intake air amount measurement device is attached so that the inlet of the bypass channel is located at a position where the flow velocity outside the bend is large.
However, the position of the intake air measuring device may not be set freely depending on the interference with the position of other parts, the cross-sectional shape of the pipe, and the like. That is, in some cases, it is necessary to dispose at least one of the inlet and the outlet of the bypass flow channel inward of the bend.

  In Patent Document 2, a rectifying plate is provided upstream of the intake air amount measuring device to reduce the flow disturbance upstream of the intake air amount measuring device. However, this rectifying plate cannot improve the uneven flow velocity distribution.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide at least one of the bypass flow path inlet and the outlet of the intake air amount measuring device inside the bend in the intake device. In the case of being arranged unevenly, it is possible to measure the flow rate with high accuracy.

An intake device of the present invention includes an air cleaner that purifies intake air taken into an internal combustion engine, a duct that sends intake air purified by the air cleaner downstream, and an intake air that is attached to the duct and measures the amount of intake air flowing through the duct A quantity measuring device.
The air cleaner has an element for filtering the intake air and a cleaner case containing the element, and an intake outlet is opened in the cleaner case in a direction different from the flow direction of the intake air passing through the element.

The duct is connected to an intake outlet of the cleaner case, and a bent portion is formed by the cleaner case and the duct so that the intake air that has passed through the element is bent and reaches the intake air amount measuring device.
The intake air amount measuring device has a bypass passage that takes in a part of the intake air flowing out from the cleaner case, and a flow rate sensor that detects an intake air flow rate in the bypass passage.

  In the flow path from the element to the intake air amount measuring device, if the direction inside the bend of the bent portion is defined as the inner peripheral side and the direction outside the bend is defined as the outer peripheral side, the intake air amount measuring device At least one of the inlet and the outlet is biased to the inner peripheral side of the duct.

Inside the cleaner case, there is provided a rectifying plate that rectifies the flow of intake air upstream of the intake air amount measuring device and guides the intake air into the bypass flow path.
The flow direction of the intake air passing through the element is the primary direction, the wall surface of the cleaner case located on the inner peripheral side of the bent portion is called the case inner peripheral wall surface, and the wall surface of the cleaner case located on the outer peripheral side of the bent portion is When calling the case outer peripheral wall surface, the distance between the case inner peripheral wall surface and the case outer peripheral wall surface in the direction orthogonal to the primary direction is B1, and the distance between the case inner peripheral wall surface and the upstream end of the rectifying plate is B2. The flow direction in the duct between the outlet and the intake air measuring device is the secondary direction, the wall surface of the duct located on the inner peripheral side of the bent portion is called the duct inner peripheral wall surface, and the duct located on the outer peripheral side of the bent portion When the wall surface is called the duct outer peripheral wall surface, the distance between the duct inner peripheral wall surface and the duct outer peripheral wall surface in the direction orthogonal to the secondary direction is A1, and the distance between the duct inner peripheral wall surface and the downstream end of the rectifying plate is A2. , A1 / Satisfy the relationship of 2> B1 / B2.

According to this, the flow rate on the inner peripheral side increases in the flow path from the element to the intake air amount measurement device by the action of the rectifying plate.
For this reason, it is possible to measure the intake air with high accuracy even when at least one of the inlet and the outlet of the bypass flow channel of the intake air measuring device is biased to the inner peripheral side of the duct.

It is a typical sectional view of an intake device ( reference example ). (A)-(c) is II-II sectional drawing of FIG. 1 ( reference example ). It is sectional drawing of an inhalation | air-intake amount measuring apparatus ( reference example ). 1 is a schematic cross-sectional view of an intake device (Example 1 ). (Example 1 ) which is a figure which shows the flow velocity of the bypass flow path inlet with respect to intake flow rate. (Example 1 ) which is a figure which shows the output fluctuation | variation of the intake air amount measuring device with respect to an intake air flow rate. (Example 1 ) which shows the output change of the inhalation | air-intake amount measuring apparatus at the time of element clogging. (Example 2 ) which is typical sectional drawing of an intake device. (Example 3 ) which is typical sectional drawing of an intake device. (Example 4 ) which is typical sectional drawing of an intake device.

  The mode for carrying out the present invention will be described in detail with reference to the following examples.

[Configuration of Reference Example ]
The configuration of the intake device 1 of the reference example will be described with reference to FIGS.
As shown in FIG. 1, an intake device 1 includes an air cleaner 2 for purifying intake air sucked into an internal combustion engine (not shown), a duct 3 for sending intake air purified by the air cleaner 2 to the downstream side, and a duct 3. An intake air amount measuring device (hereinafter referred to as AFM 4) that is attached and measures the intake air amount flowing through the duct 3 is provided.

The air cleaner 2 has an element 7 for filtering the intake air and a cleaner case 8 in which the element 7 is built.
The cleaner case 8 is formed in a substantially rectangular parallelepiped shape with resin, and an intake inlet 9 serving as an inlet for intake air into the cleaner case 8 and an intake outlet 10 serving as an intake outlet are opened on the wall surface of the cleaner case 8. Yes.

The element 7 is made of, for example, a filter medium such as a synthetic fiber nonwoven fabric or filter paper, and is disposed between the intake inlet 9 and the intake outlet 10 in the cleaner case 8. As a result, the intake air that has entered from the intake inlet 9 passes through the element 7 and travels toward the intake outlet 10.
In the cleaner case 8 of the present embodiment, the intake outlet 10 opens in a direction different from the flow direction of the intake air passing through the element 7.

That is, the intake port 9 is opened on one surface 8a of the cleaner case 8, and the intake port 10 is opened on one surface 8b opposite to the one surface 8a. However, the positions of the intake inlet 9 and the intake outlet 10 are different in one direction (vertical direction in the figure) perpendicular to the direction in which the one surface 8a and the one surface 8b face each other (referred to as the facing direction).
The element 7 is provided between the intake inlet 9 and the intake outlet 10 in one direction orthogonal to the facing direction.
For this reason, the flow direction of the intake air passing through the element 7 and the direction in which the opening surface of the intake outlet 10 faces (the normal direction of the opening surface) are different.
Note that the intake inlet 9 and the intake outlet 10 may be different from each other in the other direction (the depth direction in the drawing) perpendicular to the facing direction.

The duct 3 is provided so as to extend linearly in the direction in which the opening surface faces from the intake outlet 10 to the downstream side. An AFM 4 is assembled downstream of the intake 3 of the duct 3.
As a result, the bent portion 15 is formed by the cleaner case 8 and the duct 3 so that the intake air that has passed through the element 7 is bent and reaches the AFM 4.
That is, the intake air flowing in from the intake inlet 9 flows through the element 7 in one direction (vertical direction in the figure) orthogonal to the opposing direction, and then changes the flow direction to the intake outlet 10 to be described later. And go to AFM4.

The duct 3 may have a circular cross section as shown in FIG. 2 (a), or may have an elliptical cross section as shown in FIGS. 2 (b) and 2 (c). Moreover, a flat circular shape may be sufficient.
A duct 16 is also connected to the intake inlet 9, and the duct 16 extends linearly from the intake inlet 9 in the direction in which the opening surface faces upstream.
The duct 3 and the duct 16 may be formed of resin integrally with the cleaner case 8, or may be formed separately from the cleaner case 8. Further, for example, only a part of the upstream side of the duct 3 may be integrated with the cleaner case 8 and the downstream side may be separated.

  As shown in FIGS. 1 and 3, the AFM 4 includes a housing 19 that forms a bypass passage 18 that takes in a part of intake air flowing out from the cleaner case 8 (that is, intake air flowing through the duct 3), and a bypass passage 18. It has a known structure having a flow rate sensor 20 for detecting the intake flow rate.

That is, a bypass channel 18 is formed inside the housing 19, and an inlet (hereinafter referred to as an AFM inlet 22) of the bypass channel 18 opens toward the upstream side in the flow direction of the intake air in the duct 3. The outlet of the bypass channel 18 (hereinafter referred to as AFM outlet 23) is opened toward the downstream side in the flow direction of the intake air in the duct 3.
The flow sensor 20 is arranged in the bypass flow path 18 and outputs an electrical signal (for example, a voltage signal) according to the flow rate of air flowing through the bypass flow path 18.

[Features of Reference Example ]
Here, in the flow path from the element 7 to the intake air amount measurement device, a direction that is inside the curve of the bent portion 15 is defined as an inner peripheral side, and a direction that is outside the curve is defined as an outer peripheral side.
That is, in FIG. 1, the lower side of the duct 3 is the inner peripheral side, and the left side of the cleaner case 8 is the inner peripheral side.

  In the AFM 4, the AFM inlet 22 is located biased toward the inner peripheral side of the duct 3. For example, in this embodiment, the AFM 4 is assembled by being inserted from a mounting hole provided on the inner peripheral side of the duct 3, and a range larger than half of the opening area of the AFM inlet 22 is inside the center of the duct 3. Arranged to exist on the circumferential side.

Inside the cleaner case 8, there is provided a rectifying plate 30 that rectifies the flow of intake air upstream of the AFM 4 and guides the intake air into the bypass flow path 18.
The current plate 30 is provided downstream of the element 7 in the cleaner case 8 and extends in a plate shape along the flow direction of the intake air.

The upstream end X of the rectifying plate 30 is located on the outer peripheral side with respect to the downstream end Y of the rectifying plate 30, and the position in the flow direction of the downstream end Y of the rectifying plate 30 is the upstream end position (intake outlet position) of the duct 3. ).
Further, the position of the upstream end X of the current plate 30 is located on the outer peripheral side of the inner peripheral side end of the AFM inlet 22 and on the inner peripheral side of the outer peripheral side end of the AFM inlet 22. That is, the upstream end X is located within the range of the AFM inlet 22 in the inner and outer peripheral directions. As a result, the intake air is guided into the bypass flow path 18 of the AFM 4 by the rectifying plate 30.

  And between the upstream end X and the downstream end Y of the baffle plate 30, it has the curved shape which curves in the direction where the flow direction of intake air changes. That is, the current plate 30 is curved so as to be concave toward the inner peripheral side. The curvature decreases from the upstream side to the downstream side of the intake air.

[Effects of Reference Example ]
According to this reference example , the AFM inlet 22 is biased toward the inner peripheral side of the duct 3, and the rectifying plate 30 that rectifies the flow of the intake air and guides the intake air into the bypass flow path 18 is provided in the flow direction of the intake air. Has a curved shape that curves in the direction of change, and the curvature decreases from the upstream side to the downstream side of the intake air.

According to this, when the intake air flows along the rectifying plate 30, the flow velocity on the inner peripheral side increases in the flow path from the element 7 to the AFM 4. Further, the disturbance of the intake air flow can be reduced by the rectifying effect of the rectifying plate 30.
For this reason, even when the AFM inlet 22 is biased to the inner peripheral side of the duct 3, the flow velocity at the AFM inlet 22 can be increased, and thus the flow rate can be measured with high accuracy.

[Example 1 ]
Example 1 will be described with reference to FIG. 4 with a focus on differences from the reference example .
The same reference numerals as those in the reference example indicate the same configuration, and the preceding description is referred to.
In this embodiment, the flow direction of the intake air passing through the element 7 is the primary direction, and the wall surface of the cleaner case 8 located on the inner peripheral side of the bent portion 15 is called the case inner peripheral wall surface 31, and the outer peripheral side of the bent portion 15 The wall surface of the cleaner case 8 located at the position is called the case outer peripheral wall surface 32. The flow direction in the duct 3 between the intake outlet 10 and the AFM 4 is a secondary direction, and the wall surface of the duct 3 located on the inner peripheral side of the bent portion 15 is called a duct inner peripheral wall surface 33. The wall surface of the duct 3 located on the outer peripheral side is called a duct outer peripheral wall surface 34.

That is, a part of the one surface 8 a in the reference example is the case outer peripheral wall surface 32, and a part of the one surface 8 b is the case inner peripheral wall surface 31.
One direction (vertical direction in the figure) perpendicular to the facing direction is the primary direction, and the direction in which the duct 3 extends is the secondary direction.

The distance between the case inner peripheral wall surface 31 and the case outer peripheral wall surface 32 in the direction orthogonal to the primary direction is defined as B1, the case inner peripheral wall surface 31 in the direction orthogonal to the primary direction, and the upstream end X of the rectifying plate 30. The distance between the duct inner peripheral wall surface 33 and the duct outer peripheral wall surface 34 in the direction orthogonal to the secondary direction is B2, and the downstream end Y of the duct inner peripheral wall surface 33 and the rectifying plate 30 in the direction orthogonal to the secondary direction. The rectifying plate 30 is provided so that the relationship of the following formula (1) is established, where A2 is the distance to
A1 / A2> B1 / B2 (1)

Between the upstream end X and the downstream end Y of the rectifying plate 30, a curved shape whose curvature decreases from the upstream side to the downstream side of the intake air is exhibited as in the reference example . In addition, if the relationship of Formula (1) is materialized, between the upstream end X and the downstream end Y of the baffle plate 30 may extend linearly, and it differs from the conditions of curvature of a reference example. It may be curved under certain conditions.

[Effects of Example 2]
The effect of a present Example is demonstrated using FIGS.
An example in which the rectifying plate 30 is not provided is referred to as Comparative Example 1, an example in which the rectifying plate 30 satisfies the condition of A1 / A2 = B1 / B2 is set as Comparative Example 2, and Example 2, Comparative Example 1, and Comparative Example 2 are compared.

First, the flow velocity at the AFM inlet 22 is compared.
As shown in FIG. 5, in Example 2, the flow velocity at the AFM inlet 22 is larger than those in Comparative Example 1 and Comparative Example 2. In Comparative Example 2, although a larger flow rate can be obtained than in Comparative Example 1, it can be seen that Example 2 can obtain a larger flow rate.

Next, the output fluctuation of the AFM 4 is compared.
The vertical axis in FIG. 6 is an index indicating the output fluctuation of the AFM 4 and is the fluctuation width σ of the detection signal / the average value Q × 100 (%) of the detection signal.
As shown in FIG. 6, the output fluctuation can be made smaller in Comparative Example 2 than in Comparative Example 1, but the output fluctuation is smaller in Comparative Example 2 than in Comparative Example 1 and Comparative Example 2. In particular, in the range where the duct flow rate is small, the output fluctuation is large in Comparative Example 1 and Comparative Example 2, but in Example 2, it is small and the output fluctuation can be reduced regardless of the duct flow rate. That is, it can be seen that the disturbance of the intake air can be further reduced in the second embodiment.

Next, the output characteristic change of the AFM 4 when the element is clogged is compared.
The vertical axis in FIG. 7 shows the change in the output characteristics of the AFM 4 when the element is clogged, assuming that the output characteristic when the element is not clogged (initial state) is zero.
As shown in FIG. 7, in Example 2, output characteristics similar to those in the initial state can be obtained even when clogging occurs. In Comparative Example 1, when the element is clogged, the output tends to be smaller than that in the initial state. In Comparative Example 2, the output is smaller than that in the initial state although it is better than Comparative Example 1.

  In the element 7, foreign matter accumulates on the inner peripheral side, so that a drift occurs, and the difference between the outer peripheral side and the inner peripheral side in the flow velocity distribution increases. For this reason, in Comparative Example 1 and Comparative Example 2, the output is low, but in Example 2, the flow velocity on the inner peripheral side can be increased, so that the output characteristics do not change even when the element is clogged.

[Example 2 ]
A second embodiment will be described with reference to FIG. 8 with a focus on differences from the first embodiment.
In addition, the same code | symbol as Example 1 shows the same structure, Comprising: The previous description is referred.

In the present embodiment, the downstream end Y of the rectifying plate 30 is located downstream of the upstream end of the duct 3 in the intake air flow direction.
That is, the rectifying plate 30 is provided so as to protrude from the intake outlet 10 toward the duct 3.
According to this, it becomes possible to provide the baffle plate 30 just before AFM4, and the effect of Example 1 can further be improved.

[Example 3 ]
A third embodiment will be described with reference to FIG. 9 with a focus on differences from the first embodiment.
In addition, the same code | symbol as Example 1 shows the same structure, Comprising: The previous description is referred.
In the present embodiment, an auxiliary rectifying plate 37 that rectifies the flow of intake air on the inner peripheral side of the rectifying plate 30 is provided.
Similar to the rectifying plate 30, the auxiliary rectifying plate 37 has a curved shape in which the curvature decreases from the upstream side to the downstream side of the intake air.
The auxiliary rectifying plate 37 may extend linearly or may be curved under a condition different from the curvature condition of the rectifying plate 30.
Further, the number of auxiliary rectifying plates 37 is not limited to one, and a plurality of auxiliary rectifying plates 37 may be provided. Alternatively, one plate may be provided on each of the outer peripheral side and the inner peripheral side of the current plate 30.

  According to this, the disturbance of the intake air on the inner peripheral side can be further reduced, and the effect of the first embodiment can be further improved.

[Example 4 ]
A fourth embodiment will be described with reference to FIG. 10 with a focus on differences from the first embodiment.
In addition, the same code | symbol as Example 1 shows the same structure, Comprising: The previous description is referred.
In the present embodiment, the intersecting portion 38 between the case inner peripheral wall surface 31 and the duct inner peripheral wall surface 33 is formed in an R shape or a chamfered shape.
That is, the inner peripheral corner of the bent portion 15 has an R shape or a chamfered shape.
According to this, the disturbance of the intake air can be further reduced without causing the intake air flow to separate at the inner peripheral side corners, and the effect of the first embodiment can be further improved.

[Modification]
In the present embodiment, the AFM inlet 22 is biased to the inner peripheral side of the duct 3,
It suffices that at least one of the AFM inlet 22 or the AFM outlet 23 is biased toward the inner peripheral side of the duct 3.
For example, even when only the AFM outlet 23 is located on the inner peripheral side of the duct 3, the flow velocity on the inner peripheral side of the duct 3 is increased by the rectifying plate 30, so that intake air is easily guided to the bypass flow path 18. Thus, the flow rate can be measured with high accuracy.

  Further, in this embodiment, the AFM 4 is inserted and assembled from the mounting hole provided on the inner peripheral side wall of the duct 3, but is inserted and assembled from the mounting hole provided on the outer peripheral side wall of the duct 3. It may be.

  Further, in this embodiment, the rectifying plate 30 is provided so that the upstream end X is positioned within the range of the AFM inlet 22 in the inner and outer peripheral directions in order to give the rectifying plate 30 the function of guiding the intake air to the bypass flow path 18. However, it is sufficient that at least the position of the upstream end X is located on the outer peripheral side of the inner peripheral side end of the AFM inlet 22. Further, the rectifying plate 30 may be provided so that the upstream end X is positioned within the range of the AFM outlet 23 in the inner and outer peripheral directions.

DESCRIPTION OF SYMBOLS 1 Intake device, 2 Air cleaner, 3 Duct, 4 AFM, 7 element, 8 Cleaner case, 10 Inlet outlet, 15 Bending part, 18 Bypass flow path, 20 Flow sensor, 22 AFM inlet, 23 AFM outlet, 30 Current plate, 31 Case inner peripheral wall, 32 Case outer peripheral wall, 33 Duct inner peripheral wall, 34 Duct outer peripheral wall, 37 Auxiliary flow straightening plate, 38 Intersection

Claims (6)

An air cleaner (2) for purifying intake air taken into the internal combustion engine;
A duct (3) for sending the air purified by the air cleaner (2) to the downstream side;
An intake air amount measuring device (4) attached to the duct (3) and measuring the intake air amount flowing through the duct (3);
The air cleaner (2) has an element (7) for filtering the intake air, and a cleaner case (8) containing the element (7).
The cleaner case (8) has an intake outlet (10) opened in a direction different from the flow direction of the intake air passing through the element (7).
The duct (3) is connected to the intake outlet (10) of the cleaner case (8), and the intake air that has passed through the element (7) is passed through the cleaner case (8) and the duct (3). A bent portion (15) is formed so as to be bent and reach the intake air amount measuring device (4),
The intake air amount measuring device (4) includes a bypass passage (18) for taking in part of the intake air flowing out from the cleaner case (8), and a flow rate sensor (for detecting an intake air flow in the bypass passage (18)). 20) having an intake device,
In the flow path from the element (7) to the intake air amount measuring device (4), the direction inside the bend of the bent portion (15) is defined as the inner peripheral side, and the direction outside the bend is defined as the outer peripheral side. Then
In the intake air amount measuring device (4), at least one of the inlet (22) and the outlet (23) of the bypass flow path (18) is located biased toward the inner peripheral side of the duct (3),
In the cleaner case (8), there is a rectifying plate (for rectifying the flow of intake air upstream of the intake air amount measuring device (4) and guiding the intake air into the bypass flow path (18)). 30)
The flow direction of the intake air passing through the element (7) is a primary direction, and the wall surface of the cleaner case (8) located on the inner peripheral side of the bent portion (15) is referred to as a case inner peripheral wall surface (31), When the wall surface of the cleaner case (8) located on the outer peripheral side of the bent portion (15) is referred to as a case outer peripheral wall surface (32),
The distance between the case inner peripheral wall surface (31) and the case outer peripheral wall surface (32) in the direction orthogonal to the primary direction is B1, and the case inner peripheral wall surface (31) and the upstream end of the rectifying plate (30). The distance to (X) is B2,
The flow direction in the duct (3) between the intake outlet (10) and the intake air amount measuring device (4) is a secondary direction, and the duct ( When the wall surface of 3) is called the duct inner peripheral wall surface (33) and the wall surface of the duct (3) located on the outer peripheral side of the bent portion (15) is called the duct outer peripheral wall surface (34),
The distance between the duct inner peripheral wall surface (33) and the duct outer peripheral wall surface (34) in the direction orthogonal to the secondary direction is A1, and the duct inner peripheral wall surface (33) and the downstream end of the rectifying plate (30) (Y )) Is A2,
A1 / A2> B1 / B2
An air intake device that satisfies the above relationship . The intake device according to claim 1,
The rectifying plate (30) has a curved shape that curves in a direction in which the flow direction of the intake air changes, and the curvature of the rectifying plate (30) decreases from the upstream side to the downstream side of the intake air. Intake device characterized by. The intake device according to claim 1 or 2 ,
An air intake apparatus , wherein a downstream end (Y) of the rectifying plate (30) is located downstream of an upstream end of the duct (3) in a flow direction of intake air. In the intake device according to any one of claims 1 to 3,
An air intake apparatus comprising an auxiliary rectifying plate (37) for rectifying the flow of intake air on the inner peripheral side or the outer peripheral side of the rectifying plate (30) . In the inhalation device according to any one of claims 1 to 4,
An air intake apparatus , wherein an intersection (38) between the case inner peripheral wall surface (31) and the duct inner peripheral wall surface (33) is formed in an R shape or a chamfered shape . In the intake device according to any one of claims 1 to 5,
In the intake air amount measuring device (4), at least one of the inlet (22) and the outlet (23) of the bypass channel (18) passes through the downstream end (Y) of the rectifying plate (30) and An air intake apparatus provided so as to be located on an inner peripheral side with respect to a virtual straight line parallel to the central axis of the duct (3) .

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