JPH0285011A - Car airconditioner - Google Patents

Abstract

PURPOSE:To reduce the air noise generated in a duct by furnishing an air baffle netting for led-in air on at least one of such elements as a blow case, heater case, ventilation duct, defroster duct, and heat duct. CONSTITUTION:A heater case 5 to form a duct is connected understream a blow case 3, and accommodates an evaporator 6, heater core 7, and air mix damper 7a. Downstream this heater case 5, a defroster duct 8 with the other end opening toward the front window, a ventilation duct 9, and a heat duct 10 are connected. Therein a wire meshing 14 as an air baffle is furnished in the neighborhood of the defroster duct inlet 8a of this defroster duct 8. The mesh size shall range 0.1-0.9cm<2> if the total area of the wire meshing 14 is assumed to be 1cm<2>, provided that the number of meshes, wire dia., and shape depend upon the specifications.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an air conditioner for an automobile, particularly to reducing air noise generated in a ventilation passage.

[Prior Art] Traditionally, air conditioners for automobiles have attempted to improve the cooling and heating performance by increasing the air volume.
There was a problem in that this increase in air volume also increased noise.

Some attempts have been made to reduce noise by creating a run-up section with sufficient air to make the wind speed distribution uniform, or by rectifying the air using air guides, but these have the problem of limited vehicle space or a reduction in air volume. It's difficult.

Therefore, as disclosed in Japanese Patent Publication No. 57-27994, an attempt has been made to improve the blower to rectify the air and reduce the noise.

[Problem to be solved by the invention]

Research on noise reduction has so far focused on blowers, but fluid noise generated in the ventilation ducts accounts for a large proportion of the noise inside a vehicle.

The sources of fluid noise generated within the ventilation path are mainly near the vent outlet grille and defroster duct, or downstream of the air guide for temperature control performance. Fluid noise is generated from these locations due to limitations in installation space, layout, curvature of the ventilation ducts, sudden expansion or contraction of the ventilation duct area, etc. in automotive air conditioners. This is because the wind speed distribution is disturbed. (Figure 13 shows the wind speed distribution near the defroster duct inlet 8a.) This disturbance in the wind speed distribution causes air to collide with each other, and the energy is transmitted as sound waves, causing noise. Ta.

In addition, this disturbance in the wind speed distribution creates a high wind speed region and generates a high wind speed flow. Then, the dynamic pressure component of this high wind speed flow collides with the instrument panel 8C, for example, as shown in FIG. 14. Noise is generated when the dynamic pressure component of the high wind speed flow collides with this instrumental panel 8C, and the turbulent air that collides with the instrument panel and bounces off, and the dynamic pressure component of the high wind speed flow that blows up. There was a problem in that the collision caused noise.

The present invention aims to suppress the decrease in air volume and reduce noise.

[Means to solve the problem]

Air blower case, heater case, ventilation duct,
At least one of the defroster duct and the heat duct
The system adopts a configuration in which an air rectifying network is installed to straighten the air introduced into the system and make the wind speed distribution uniform.

[Effect]

The introduced air is rectified by passing through the air straightening network, and the wind speed distribution is made uniform, thereby reducing vibrations of the air and collisions between the air.

In addition, when the high wind speed flow generated in the high wind speed region due to the disturbance of the wind speed distribution passes through the air straightening network, it collides with the line part of the air straightening network, the dynamic pressure component of the high wind speed flow is reduced, and the wind speed distribution becomes uniform.

〔Effect of the invention〕

As described above, since there is no need to provide a rectifying plate such as an air guide to rectify the air, it is possible to suppress the decrease in air volume to a low level.

In addition, it is possible to reduce noise by reducing air vibrations and collisions between air caused by disturbances in wind speed distribution, and further suppresses the dynamic pressure component of high wind speed flows that occur in high wind speed regions due to disturbances in wind speed distribution. By doing so, it is possible to prevent the air from strongly colliding with the inner wall of the duct, etc., and also to reduce noise because the high wind velocity flow that has collided with the inner wall of the duct does not collide with the high wind velocity flow that is further introduced. Can be done.

(Example〕 Hereinafter, one embodiment of the present invention will be described based on the drawings.

As shown in Figure 1, the outside air inlet 1a is located in the outside air switching box l.
The inside air circulation port 1b is open.

Further, the inside/outside air switching box 1 is provided with an inside/outside air switching damper 2, and the inside/outside air switching damper 2 switches between inside air circulation and outside air introduction.

A blower case 3 is connected to the downstream side of the inside/outside air switching box 1,
A blower 4 is provided within the blower case 3.

A heater case 5 (including a tala duct, a connecting duct, etc.) forming a ventilation path is connected to the downstream side of the ventilation case 3. Inside the heater case 5 are an evaporator 6 that removes heat from the air, a heater core 7 that heats the air, and an air mix damper that adjusts the amount of air passing through the heater core 7 to adjust the temperature of the air blown into the vehicle interior. 7a is provided.

Further, on the downstream side of the duct 5, there is a defroster duct 8 with one end opening into the duct 5 and the other end opening toward the front land door side. A ventilation duct 9 opens into the duct 5, and a heat duct 10 opens into the duct 5 at one end and near the bottom of the vehicle interior at the other end.

Each duct is provided with a defroster damper 11, a ventilation damper 12, and a heat tamper 13 for switching between communicating and blocking the ventilation path.

And defroster duct population 8 of defroster duct 8
Gold that is an air rectification network near a! 1114 is provided.

As shown in FIG. 2, a wire mesh 14 made of a material such as iron or stainless steel is connected and fixed to the defroster duct 8 near the defroster duct inlet 8a with screws or the like.

The area of the hole in wire mesh 14 is gold! The total area of 1i14 is 1c
4, the range is about 0.1 to 0.9 cta, the number of holes is about 10 x 10 to 60 x 60 holes in this square, and the wire diameter of the wire mesh 14 is about 25 m square. 0
．． Approximately 15 to 0.5 tm is desirable.

The number of holes, wire diameter, shape, etc. of the wire mesh 14 are arbitrarily selected depending on the specifications.

Air sucked in by the blower 4 passes through the evaporator 6 and the like, and is led to each duct.

Air is guided to the defroster duct 8 by opening the defroster damper 11. Compared to the ventilation passage area of the heater case 5, the ventilation passage area of the opening 8b of the defroster duct 8 on the side of the heater case 5 is small, and the defroster duct 8 is curved with respect to the ventilation direction inside the heater case 5. Therefore, the wind speed is disturbed, and the air guided to the defroster duct 8 has an uneven wind speed distribution. At this time, wire mesh 14
When air passes through, the dynamic pressure component of the high wind speed generated in the high wind speed region collides with the line portion of the wire mesh 14, thereby being reduced. By reducing this dynamic pressure component, gold! 1
The air passing through 114 is rectified and has a uniform wind speed distribution.

Therefore, vibrations of air particles and collisions between air particles are reduced.

Then, the high wind speed flow does not strongly collide with the instrument panel 8c, and noise is reduced.

In addition, the air that collided with the instrument 8c and the air that blows up no longer collide strongly, and noise is reduced.

FIG. 3 shows the wind speed distribution when a wire mesh 14 is provided near the defroster duct inlet 8a.

The maximum wind speed when there is no wire mesh 14 is approximately 12 W/S (13th
), but by providing the wire mesh 14, the maximum wind speed is about 6 m/s, which is about half the wind speed when there is no wire mesh 14.

In addition, when there is no wire mesh 14, the width of the wind speed distribution is approximately 1 to 12
m/S (FIG. 13) is reduced to about 2 to 6 m/S by providing the wire mesh 14, and the wind speed distribution is made uniform.

The effect on the air volume by attaching the wire mesh 14 is basically related to the area of the holes in the wire mesh 14, and the effect on the air volume can be reduced by increasing the area of the entire wire mesh.

In other words, the part that most affects the air volume is the cross-sectional area of the opening 8b, and by making this cross-sectional area equivalent to the total area of the holes in the gold w414, reduction in the air volume can be suppressed.

According to experiments conducted by the present inventors, the shape of the wire mesh is changed to the sixth shape so that the total area of the holes in the wire mesh 14 is equal to the cross section of the opening 8b.
As shown in the figure, when using gold m14 which has a convex shape on the downstream side, or gold 5I114 which has a convex shape on the downstream side and a curved surface as a whole as shown in FIG. The reduction in air volume was about 2-j% compared to the case without No. 14.

Figure 4 shows the relationship between frequency and noise level.

(Noise level measurement position: Driver's seat window side) Without wire mesh a
The peak value of the noise level in the case of b was about 62 dB-A, but the peak value of the noise level in the case of wire mesh b was about 58 dB-A, and the peak value of the noise level was about 4 dB-A.
It was reduced by B-A.

In addition, the overall value of the noise level in the case of a without wire mesh in the entire 1/3 octave band frequency is approximately 68.5.
dB-A, and the overall value of the IF sound level in case b with wire mesh is about 65.5 dB-A.

In other words, the overall noise level was reduced by about 3 dB·A, an effect so great that it was clearly noticeable even to the auditory senses.

FIG. 5 shows the relationship between the area ratio (total area of holes in wire mesh/cross-sectional area of ventilation road surface) and bench air volume, and the relationship between area ratio and actual vehicle noise level. (Noise level measurement position: i1 transfer window side) The smaller the area ratio, the lower the air volume, but the air volume without wire mesh is approximately 43 On (/hT: MEC s#40 (25 mm x 25 + nm), which has the lowest air volume. There are 40 x 40 holes in the area.) Wire diameter of wire mesh 0.25
yra is about 418 rrr/h, and the reduction in air volume is only about 12%/h.

The overall value of the noise level without wire mesh is approximately 69
．． 2 dB-A, and the overall value of the noise level when the lowest noise level is mesh 20 and the wire diameter of the wire mesh is 0.42mm+ is about 66.7 dB-A, the overall noise level is 4M. Mo2.5 d B・A
was also reduced.

1/3 octave band frequency is 315-500 Hz
The value of the noise level without wire mesh is approximately 66.
7 dB-A, mesh # with the lowest noise level
20. When the wire diameter of the wire mesh is 0.42 iua, the noise level value is approximately 63 dB-A, and the noise level value is 3.4
dB-A was also reduced.

Next, a case where gold M414 is provided in the ventilation duct will be described.

As shown in FIG. 8, there is gold in the ventilation duct 9 between the duct 5 and the bench air outlet 15 as in one embodiment. 2i14 is provided.

The action and effect are the same as in the first embodiment.

Figure 9 shows the relationship between frequency and noise level.

(Noise level measurement position: 15 from the center vent outlet
0)) The peak value of the noise level in the case of C without wire mesh is approximately 61.5
d B -A, but in the case of d with the wire mesh, the peak value of the noise level was about 60 dB -A, and the peak value of the noise level was reduced by about 1.5 d B -A.

In addition, the overall value of the noise level without wire mesh in the entire 1/3 octave band frequency is approximately 69.5 d
B - A, and the overall value in the case of d with wire mesh is about 68 dBA.

In other words, the overall noise level was reduced by about 5 dB for a month, an effect so great that it was noticeable to the ears.

FIG. 10 shows the relationship between the area ratio and the bench air volume, and the relationship between the area ratio and the actual vehicle noise level. (Noise level measurement position: around 150 nu from the center vent outlet) The smaller the area ratio, the lower the air volume, but the air volume without wire mesh is approximately 695 m / h, which is the mesh with the lowest air volume. #40, wire mesh wire diameter 0.25ffIIm
The air flow rate is 680 rrr/h, and the reduction in air volume is only about 10 r.
It is about rr/h.

The overall value of the noise level without wire mesh is approximately 6.
9.6 dB-A, and the overall value in the case of mesh #30, which has the lowest noise level, and the wire diameter of the wire mesh is 0.23 mm, is approximately 67.3 dB-A, which is the overall value of the noise level. The value was reduced by about 1.7 dB-A.

1/3 octave band frequency is 3.15K~5KH
, the value of the noise level without wire mesh is approximately 61
．． 5 d B-A mesh # with the lowest noise level
20. When the wire diameter of the wire mesh was 0.23 mm, the noise level was approximately 57.3 dB-A, and the noise level was reduced by 4.2 dB-A.

Furthermore, it is also effective to provide a wire mesh at the noise-generating location of the heater unit or the blower case.

Considering the installation position of the wire mesh, the air volume, etc., it may be possible to cover a part of the ventilation path, and the specifications of the wire mesh, such as the mesoche wire diameter, can be selected arbitrarily.

Further, by providing the wire mesh, it is possible to prevent vibrations of the duct etc. caused by pressure fluctuations due to air turbulence.

As shown in FIG. 11, the vibration of the duct without the wire mesh occurred within ±0.2G.

When a wire mesh is provided, the vibration of the duct occurs within ±0.1G, as shown in FIG. 12, and the vibration is reduced to about half compared to the case without the wire mesh.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an embodiment of the present invention, Fig. 2 is a cross-sectional view of main parts of an embodiment of the invention, and Fig. 3 shows a wind speed distribution of an embodiment of the invention. FIG. 4 is a characteristic diagram showing the relationship between frequency and noise level in an embodiment of the present invention, and FIG. 5 is a relationship between area ratio and bench air volume and area ratio in an embodiment of the present invention. 6 is a perspective view showing one shape of the wire mesh, FIG. 7 is a perspective view showing another shape of the wire mesh, and FIG. 8 is another embodiment of the present invention. FIG. 9 is a characteristic diagram showing the relationship between frequency and noise level in another embodiment of the present invention, and FIG. 10 is a diagram showing the relationship between area ratio and bench air volume in another embodiment of the present invention. Characteristic diagram showing the relationship and relationship between area ratio and actual vehicle noise level, No. 11
FIG. 12 is a characteristic diagram showing the relationship between time and vibration in the conventional technology, FIG. 12 is a characteristic diagram showing the relationship between time and vibration in the present invention, and FIG. 13 is a wind speed distribution diagram showing the wind speed distribution in a conventional defroster duct. FIG. 14 is a schematic diagram showing the air flow in a conventional defroster duct. 3...Blower case 24...Blower, 5...Heater case, 7...Heater core, 7a...Air mix damper. 8... Defroster duct, 9... Ventilation duct, 10... Heat duct 14... Air rectification network.

Claims (1)

[Claims] A ventilation case having a ventilation means for introducing external air into the interior, a heater case having an opening connected to the ventilation case and through which external air is introduced, and the heater case. a heater core that is arranged in a case and heats the introduced air; an airmic damper that divides the external air introduced through the opening into air that flows toward the heater core and air that flows bypassing the heater core; and the heater An air conditioner for an automobile, which is formed in a case and has a ventilation duct connected to a vent outlet, a defroster duct connected to a defroster outlet, and a heat duct connected to a heat outlet, the blower case, the heater case, and the ventilation An air conditioner for an automobile, characterized in that at least one of the duct, the defroster duct, and the heat duct is provided with an air rectification network that rectifies introduced air and makes the wind speed distribution uniform.