JPH1018925A - Air intake device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce turbulence generated in the communication port part of a silencing chamber provided on the curved part of the air intake passage of an internal combustion engine, to stabilize the flow of intake air. SOLUTION: A dust part 27 passing a filter element 24 and adopted as a passage for intake air, is provided in an air cleaner cap 25 to partitionedly form a silencing chamber 28. A gap adopted as a communication port 30 is opened on the downstream side of a duct part 27 to arrange an air cleaner outlet duct part 29. The opening width of the communication port part 30 is narrow on the outer side of a curved part 31, by forming a ventilation guide piece 32 on the outer side of the opening end of the duct part 27 to make the tip part of the piece 32 close to the air cleaner outlet duct part 29. Turbulance generated in the communication port part 30 can be effectively restrained by setting so as to be W/D>=0.2, and H/L>=0.5 (wherein, W is the width of the ventilation guide piece 32; H is the length of the ventilation guide piece 32; D is the inner diameter of the duct part 27; and L is the opening width of the communication port part 30).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for an internal combustion engine having a silencing chamber in an intake passage for reducing intake noise.

[0002]

2. Description of the Related Art In order to reduce intake noise generated from an intake system of an internal combustion engine, as shown in FIG.
A sound-absorbing chamber 13 is provided at a curved portion of the intake passage 12 at a connection portion between the air-conditioning chamber and the intake duct 11 so as to surround the outer periphery of the curved portion. There is a configuration in which the sound of the intake sound propagating upstream in the intake duct 11 is guided from the communication port portion 14 into the muffling chamber 13 to be attenuated by communicating the intake air with the inside of the intake passage 12.

[0003]

By the way, when the flow of the intake air changes direction along the curved portion of the intake passage 12 in the air cleaner 10, the intake air tends to flow toward the outer periphery of the curved portion of the intake passage 12 due to inertia. There is. For this reason, if the communication port portion 14 having a uniform width is formed on the entire periphery of the bent portion of the intake passage 12 as in the above-described conventional configuration, as shown by the arrow A in FIG. The intake air flowing while changing the direction along the outer peripheral wall surface flows straight through the communication port portion 14 due to inertia and collides with the edge of the intake duct 11 on the downstream side of the communication port portion 14, thereby generating turbulent flow. Thus, there is a disadvantage that the intake resistance increases and the output of the internal combustion engine decreases.

The present invention has been made in view of such circumstances, and an object of the present invention is to reduce turbulent flow generated in a communication opening of a sound deadening chamber provided at a bent portion of an intake passage. It is an object of the present invention to provide an intake device for an internal combustion engine that can be used.

[0005]

According to a first aspect of the present invention, there is provided an intake system for an internal combustion engine, wherein a communication port for communicating a muffling chamber and the intake passage is provided with "mainly" intake air. It is opened inside the bent portion of the passage. Here, the term “mainly” is not limited to the configuration in which the communication port is provided only inside the curved portion of the intake passage. The opening width of the communication port is large inside the curved portion and outside the curved portion. The purpose is to include a reduced configuration. In other words, it means that there is no communication port outside the bent portion where the intake air flows in one direction, or that the communication port is small even if there is. By doing so, turbulence generated at the communication port portion is reduced as compared with the related art.

By forming the silencing chamber so as to surround the bent portion of the intake passage, the silencing chamber and the intake passage can be integrated.

In this case, the communication port is formed on the entire periphery of the bent portion of the intake passage, and a ventilation guide piece is formed outside the bent portion outside the communication port. May be narrowed. In this configuration, the intake passage 1
The flow of the intake air flowing along the outer peripheral wall surface in 2 is smoothly guided to the downstream side of the communication port by the ventilation guide piece, and the turbulent flow generated in the communication port is effectively suppressed.

According to a fourth aspect of the present invention, by providing the muffler chamber integrally with an air cleaner provided on the upstream side of the intake passage, it is possible to make the muffler more compact as compared with a configuration in which these are separately provided. I do. Then, a duct portion forming a ventilation passage on the downstream side of the filter element in the air cleaner and a cylindrical air cleaner outlet duct portion formed on the downstream side thereof are opposed to each other with a gap therebetween.
The gap is used as a communication port of the sound deadening chamber.

According to a fifth aspect of the present invention, if the width of the ventilation guide piece is W, the length of the ventilation guide piece is H, the inner diameter of the duct is D, and the opening width of the communication port is L, W /D≧0.2 and H / L ≧ 0.5. By setting such a dimensional relationship, the function of the ventilation guide piece (the function of guiding the flow of the intake air and the function of suppressing the turbulent flow) can be effectively exerted as described later, and the flow of the intake air can be reliably and smoothly performed. can do.

As described above, in the conventional configuration shown in FIG. 7, a turbulent flow is generated in the communication port 14 of the sound deadening chamber 13 and the flow of the intake air is disturbed. When the air flow meter 15 is installed, the air flow meter 15 is installed in the unstable flow of the intake air disturbed at the communication port portion 14, and the measured intake air amount of the air flow meter 15 is affected by the disturbance of the intake flow. As a result, there is a disadvantage that the measurement error increases.

On the other hand, in claim 6, an air flow meter is installed in the intake passage downstream of the communication port. However, as described above, in the present invention, the air flow meter is generated at the communication port as compared with the related art. Since the turbulent flow is suppressed, it is possible to install the air flow meter in the stable intake flow,
The measurement error of the air flow meter due to the disturbance of the flow of the intake air can be reduced.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIGS. An air cleaner 2 is provided upstream of an intake duct 21 connected to the intake side of the internal combustion engine 20.
2 are provided. The air cleaner 22 includes a filter element 24 housed in an air cleaner case 23 and an air cleaner cap 25 mounted downstream of the air cleaner case 23. The inside of the air cleaner case 23 serves as an intake passage, and dust in the air is removed while the air sucked from the air cleaner inlet 26 formed in the air cleaner case 23 passes through the filter element 24.

The air cleaner 22 is integrally provided with a muffling chamber 28 as follows. That is, inside the air cleaner cap 25, the duct portion 2 that guides the flow of the intake air that has passed through the filter element 24 to the air cleaner outlet duct portion 29 while gradually changing its direction.
The duct 27 and the air cleaner cap 25 define a muffling chamber 28 that surrounds the outer periphery of the duct 27.

The air cleaner outlet duct 29 is
Integrally formed on the downstream side of the air cleaner cap 25,
On the downstream side of the duct portion 27 in the air cleaner cap 25, an air cleaner outlet duct portion 29 is arranged to face the air cleaner outlet duct 30 with a gap provided therebetween. These duct parts 2
A curved portion 31 of an intake passage is constituted by the air cleaner outlet duct portion 29 and the air cleaner outlet duct portion 29, and a muffling chamber 28 is formed so as to surround the outer periphery of the curved portion 31. It is communicated at 30.

In this case, a ventilation guide piece 32 for guiding the flow of intake air is integrally formed outside the open end of the duct section 27, and the tip of the ventilation guide piece 32 approaches or abuts on the air cleaner outlet duct section 29. By doing so, the opening width of the communication port 30 outside the bent portion 31 is reduced or made zero, thereby realizing a configuration in which the communication port 30 is mainly opened inside the bent portion 30 as described in the claims. doing.

As described above, in the present embodiment, the filter element housing chamber and the sound deadening unit are formed in a single box-shaped housing as a whole by the members 23, 25, 27, and 29 serving as air cleaner housings for housing the filter element 24. A chamber 28 is formed. Moreover, the communication port 30
Is provided in the air cleaner cap 25 as an air cleaner housing, so that airtightness can be achieved at the joint between the air cleaner case 23 and the air cleaner cap 25 as the air cleaner housing and the joint between the duct 27 and the air cleaner cap 25. good.

Here, as shown in FIG. 2, the width of the ventilation guide piece 32 is H, the length of the ventilation guide piece 32 is H, the inner diameter of the duct portion 27 (air cleaner outlet duct portion 29) is D, and the communication port portion is formed. Assuming that the opening width of the opening 30 is L, W / D ≧ 0.2 and H / L ≧ 0.5 (the reason will be described later).

On the other hand, as shown in FIG. 1, the intake duct 21 is connected to the downstream side of the air cleaner outlet duct section 29 located downstream of the communication port section 30 via the tubular body 34 of the air flow meter 33. I have. The air flow meter 33 used here is a thermal air flow meter in which an intake air amount sensor 35 (a heating element and a temperature sensing element) is installed in a tubular body 34 forming an intake passage.

In the above configuration, the air sucked into the air cleaner case 23 from the air cleaner inlet 26 passes through the filter element 24 and passes through the duct 27
It flows while gradually changing its direction along the curved shape of. This flow of intake air is smoothly guided to the downstream side of the communication port 30 by the ventilation guide piece 32 in the process of passing through the communication port 30, and the generation of turbulence in the communication port 30 is effectively suppressed. Thus, the flow of intake air downstream of the communication port 30 is stabilized. In this stable flow of intake air, the air flow meter 33
Is installed, and the air flow meter 3
3, the measurement error is reduced, and the measurement accuracy of the intake air amount is improved. In addition, the sound wave of the intake sound propagating upstream in the intake duct 21 is guided from the communication port 30 into the muffling chamber 28 and attenuated, so that the intake sound leaking to the outside is reduced.

Next, the influence of the position, width W, and length H of the ventilation guide piece 32 on the flow of intake air will be considered. When the flow of the intake air passing through the air flow meter 33 is disturbed, the output of the air flow meter 33 (measured intake air amount) fluctuates, and the output fluctuation width increases as the disturbance of the intake flow increases. Therefore, the optimum shape of the ventilation guide piece 32 can be evaluated based on the output fluctuation width of the air flow meter 33, and data of the evaluation test are shown in FIGS.

FIG. 3 is a graph showing the relationship between the position of the ventilation guide piece 32 (the angle at which the outermost position of the duct 27 is 0 °) and the output fluctuation of the air flow meter 33. As is clear from this graph, as the position of the ventilation guide piece 32 approaches 0 ° (the outermost position of the duct portion 27), the output fluctuation width of the air flow meter 33 decreases, and the position of the ventilation guide piece 32 becomes 0 °. When the air flow meter 3
3, the output fluctuation width is minimized, and the turbulence of the intake air flow is minimized. In other words, the intake air flowing while gradually changing the direction along the bend of the duct portion 27 flows toward the outer periphery of the duct portion 27 by inertia, so that the ventilation guide piece 32 is
7, the turbulence of the intake air flow can be minimized.

FIG. 4 is a graph showing the relationship between the width W of the ventilation guide piece 32 and the output fluctuation of the air flow meter 33. As is apparent from this graph, the ventilation guide piece 32
Of the width W and the inner diameter D of the duct portion 27 is 0 to 0.
In the range of 2, the output fluctuation width of the air flow meter 33 decreases as the W / D increases, and in the range of W / D ≧ 0.2, the output fluctuation of the air flow meter 33 becomes almost constant near the minimum value. Therefore, if W / D ≧ 0.2, the turbulence of the flow of intake air is substantially minimized.

FIG. 5 is a graph showing the relationship between the length H of the ventilation guide piece 32 and the output fluctuation of the air flow meter 33. As is clear from this graph, the ventilation guide piece 3
The ratio H / L of the length H to the opening width L of the communication port 30 is 0.
In the range of 0.5 to 0.5, the output fluctuation width of the air flow meter 33 decreases as H / L increases, and H / L ≧
In the region of 0.5, the output fluctuation of the air flow meter 33 becomes almost constant near the minimum value. Therefore, if H / L ≧ 0.5, the turbulence of the flow of intake air is substantially minimized.

From the above test results, in this embodiment, the ventilation guide piece 32 is formed at the outermost position (0 °) of the duct portion 27, and W / D ≧ 0.2 and H / L ≧ 0. By setting to 5, the functions of the ventilation guide piece 32 (the function of guiding the flow of the intake air and the function of suppressing the turbulent flow) are effectively exhibited. Accordingly, as shown in FIG. 6, in the present embodiment, the output fluctuation of the air flow meter 33 is significantly reduced as compared with the conventional case (the configuration of FIG. 7), and the measurement error of the air flow meter 33 is reduced. The measurement accuracy of the intake air volume is improved. In particular, an area where the intake air flow rate is 70 g / s or less (that is, an internal combustion engine low rotation area).
The effect of reducing the output fluctuation of the air flow meter 33 is large,
The measurement accuracy of the intake air amount has been greatly improved compared to the past, and it is greatly useful for improving the controllability of the engine in the low rotation speed region.

In this embodiment, the ventilation guide piece 32 is formed in the duct 27, but this ventilation guide piece 32 may be formed in the air cleaner outlet duct 29. Also,
The duct 27, the ventilation guide piece 32, and the air cleaner outlet duct 29 may be integrally formed.

Further, in the present embodiment, since the noise reduction chamber 28 is provided integrally with the air cleaner 22, there is an advantage that the size can be reduced as compared with a configuration in which these are separately provided. However, in the present invention, the muffling chamber 28 may be provided at a position different from the air cleaner 22. In short, a sound deadening chamber is provided at the bent portion of the intake passage so as to surround the outer periphery of the bent portion,
What is necessary is just to open the communication port for communicating the silencing chamber with the intake passage “mainly” inside the bent portion of the intake passage. Here, the term “mainly” is not limited to the configuration in which the communication port is provided only inside the curved portion of the intake passage. The opening width of the communication port is large inside the curved portion and outside the curved portion. The purpose is to include a reduced configuration.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an air cleaner and a downstream peripheral portion thereof according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a portion around a communication port taken along line II-II of FIG.

FIG. 3 is a graph showing the relationship between the position of a ventilation guide piece and output fluctuation of an air flow meter.

FIG. 4 is a graph showing the relationship between the width W of the ventilation guide piece and the output fluctuation of the air flow meter.

FIG. 5 is a graph showing the relationship between the length H of the ventilation guide piece and the output fluctuation of the air flow meter.

FIG. 6 is a graph showing a relationship between an intake air flow rate and an output fluctuation of an air flow meter.

FIG. 7 is a longitudinal sectional view of an air cleaner of a conventional structure and a peripheral portion thereof on the downstream side thereof.

[Explanation of symbols]

20 internal combustion engine, 21 intake duct (intake passage), 22
... air cleaner, 23 ... air cleaner case, 24 ... filter element, 25 ... air cleaner cap, 26
... air cleaner inlet, 27 ... duct, 28 ... sound deadening chamber, 29 ... air cleaner outlet duct, 30 ... communication port, 31 ... bend, 32 ... ventilation guide piece, 33 ... air flow meter, 35 ... intake air amount sensor.

Claims (6)

[Claims] 1. An intake device for an internal combustion engine having a muffler chamber communicating with an intake passage for introducing air into the internal combustion engine through a communication opening, wherein the communication opening is mainly opened inside a bent portion of the intake passage. An intake device for an internal combustion engine. 2. The muffler chamber is formed so as to surround the outer periphery of the bent portion.
An intake device for an internal combustion engine according to claim 1. 3. The communication port is formed on the entire circumference of a curved portion of the intake passage, and a ventilation guide piece for guiding the flow of intake air is provided outside the curved portion outside the curved portion. 3. The intake device for an internal combustion engine according to claim 1, wherein the intake device is formed so as to narrow the intake air pressure. 4. A duct section which is provided integrally with an air cleaner provided on the upstream side of the intake passage, forms a suction passage on a downstream side of a filter element in the air cleaner, and a duct section on the downstream side thereof. The formed air cleaner outlet duct is opposed to the air cleaner outlet duct with a gap serving as the communication port formed therebetween to form the bent portion, and the ventilation guide piece is formed in one of the duct portion and the air cleaner outlet duct portion. The intake device for an internal combustion engine according to any one of claims 1 to 3, wherein: 5. When the width of the ventilation guide piece is W, the length of the ventilation guide piece is H, the inner diameter of the duct is D, and the opening width of the communication port is L, W / D ≧ 0. 5. The intake device for an internal combustion engine according to claim 4, wherein H / L ≧ 0.5. 6. The intake device for an internal combustion engine according to claim 1, wherein an air flow meter for measuring an intake air amount is provided in an intake passage downstream of the communication port.