JPS6344258Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for reducing noise emitted from an automobile engine, particularly intake noise.

As external noise from automobiles has become a social issue in recent years, it is necessary to sufficiently reduce the noise emitted from the engine. For this reason, in recent years engine rooms have been made into sound insulating structures and exhaust noise has also been reduced, resulting in an increase in the relative level of intake noise. As a means for reducing such intake noise, it has been known to attach an intake silencer called a resonator to the intake system.

However, in the past, as shown in Figure 1, for example, the resonator A as a separate component was installed in the intake passage upstream of the air cleaner B, which resulted in an enlarged engine room and the need to make the engine room more compact. The drawback was that it could not meet the demands of recent years. In addition, in Figure 1, C
is the engine, and D is the hood that opens and closes the engine room.

The present invention was made to eliminate these conventional drawbacks. A hood that covers the engine room and silk cloth that reinforces this hood form a sealed space, and this space is transformed into a resonance chamber ( The aim is to reduce the number of parts and make the engine room more compact by effectively using it as a resonance chamber.

The present invention will be explained in detail below based on an illustrated embodiment.

FIG. 2 is a perspective view of a part of a small bonnet-type truck equipped with an embodiment of the present invention. On the lower surface of the hood 2, which opens and closes the upper surface of the engine room housing the engine 1 and auxiliary equipment (not shown), By attaching a silk cloth 3 reinforcing the hood 2, the silk cloth 3 and the hood 2 form a substantially sealed space 4 having a considerable volume.

Further, an air cleaner 5 attached to the engine 1
An intake duct 6 extending from the air intake port to an air intake port (not shown) is provided with a connecting duct 7 that extends toward the silk cloth 3, and a small hole 8 is formed in the silk cloth 3 opposite to the tip of the duct 7. When the hood 2 is closed, the intake duct 6 and the space 4 are communicated through the inside of the connecting duct 7 and the small hole 8.

In the above configuration, since the hood 2 is normally closed, the intake duct 6 and the space 4 are maintained in communication. Therefore, when air vibrations occur in the intake duct 6 as the engine 1 operates, the pressure in the space 4 changes with the same period as the vibration. Therefore, if the volume of the space 4 is appropriately selected, the space 4 acts as a resonance chamber in the same way as a conventional resonance chamber, so there is no risk that noise due to intake pulsation will reach an air intake port (not shown).

That is, in the present invention as well, the space formed by the hood and the silk cloth reinforcing the hood becomes a resonance chamber and reduces the intake noise of the engine, as in the case of the conventional resonance type muffler. Therefore, it is not necessary to house a large-volume resonance container in the engine room as in the conventional case, and the number of parts can be reduced and the engine room can be made more compact.

It goes without saying that the resonance frequency (frequency) of the space changes depending on the volume of the space and the cross-sectional area and length of the connection passage formed by the connection duct.

In addition, in the embodiment, the connecting duct is constructed of a bellows tube, and when the hood is closed, the tip of the connecting duct is pressed against the lower surface of the silk cloth to establish airtight communication between the space and the intake passage. By making the amount of expansion and contraction of the duct sufficiently large, the intake passage and the space may be maintained in communication at all times, and the duct may be manually separated only when necessary, such as for maintenance.

As explained above, according to the present invention, the space formed by the hood and silk cloth, which was previously a waste of space, is effectively used as a resonance space, so it can be separated as a separate component as in the past. There is no need to house the resonant container in the engine room. Therefore, the engine room can be made more compact, the maintenance and inspection workability of the engine can be improved, and the number of parts can be reduced to reduce weight and cost.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of a conventional example, FIG. 2 is a schematic perspective view of an embodiment of the present invention, and FIG. 3 is a sectional view of the main parts. 1... Engine, 2... Hood, 3... Silk cloth, 4... Space, 5... Air cleaner, 6...
Intake duct, 7...Connection duct, 8...Small hole.

Claims (1)

[Scope of utility model registration request] A silk cloth is attached to the inner surface of a hood that covers the engine room, and the hood and silk cloth form a sealed space, and a connection is made in which the intake passage of the engine and the space are communicated through a small hole at least when the hood is closed. A noise reduction device for an automobile engine, which is equipped with a device.