JP2001073895A - Intake structure of internal combustion engine - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide an intake structure of an internal combustion engine capable of reducing discharge noise from an intake path over the entire frequency range. An intake structure of an internal combustion engine according to the present invention has an intake path 9 of an engine 1 in which an upstream end has substantially the same diameter as the inside diameter of the intake path 9, a downstream end has a smaller diameter than the inside diameter of the intake path 9, and a downstream side. The air pulsation of the engine 1 is canceled by the intake pulsation of a phase shifted and reflected by the outer peripheral surface of the air funnel 10 by providing an air funnel 10 of a shape that gradually reduces in diameter as the air pulsation progresses. Reduced noise.
In this case, the intake pulsation in any frequency range can be attenuated, so that only one component of the air funnel 10 can reduce the discharge sound from the intake path 9 over the entire frequency range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an intake structure for an internal combustion engine.

[0002]

2. Description of the Related Art In an automobile engine (internal combustion engine), the sound of intake air pulsation accompanying engine operation is discharged from an intake port of an air cleaner.

[0003] As a countermeasure against noise, measures are usually taken to reduce discharge noise (intake sound) from the intake port in the intake path of the engine.

As a countermeasure, conventionally, an intake resonator (intake damper) is attached between an air cleaner and an engine to suppress resonance noise.

[0005]

By the way, the intake resonator exerts its effect only at a specific resonance frequency.

For this reason, in order to reduce the entire frequency range of the discharge sound in the intake resonator, measures must be taken for many resonance frequencies. That is, there is a problem that sufficient noise reduction cannot be performed unless many intake resonators are used.

Particularly, in a supercharged engine (such as an engine supercharged by a supercharger or an engine supercharged by a turbocharger), supercharging pulsation due to rotation of the supercharger causes primary supercharge,
Since the supercharged secondary, the supercharged tertiary,..., And the nth order are generated up to the high-frequency component region, countless intake resonators corresponding to each frequency component are required to sufficiently reduce the discharge noise. .

The present invention has been made in view of the above circumstances. It is an object of the present invention to provide an internal combustion engine capable of reducing discharge noise from an intake passage over a whole frequency range with a relatively simple configuration. It is to provide an intake structure of an engine.

[0009]

According to a first aspect of the present invention, there is provided an intake structure for an internal combustion engine in which an air funnel is merely provided in an intake path of the internal combustion engine, and the discharge sound caused by intake pulsation is completely reduced. Reduced in the frequency range.

That is, if an obstacle is placed in the intake path,
The intake pulsation from the internal combustion engine toward the intake port of the intake path is reflected by an obstacle, and a pulsation having a shifted phase, that is, an intake pulsation having an opposite phase is generated.

Therefore, the present invention has been developed in such a manner that this phenomenon is exerted in the intake passage without causing unnecessary intake pressure loss.
The intake path was provided with an air funnel whose upstream end had substantially the same diameter as the inside diameter of the intake path, whose downstream end had a smaller diameter than the inside diameter of the intake path, and whose diameter gradually decreased toward the downstream side.

In this air funnel, a small-diameter end is opened at the center of the intake passage, and a path portion around the opening is blocked by an inclined outer peripheral surface following the small-diameter end. Among them, the intake pulsation heading around the small-diameter end is reflected on the outer peripheral surface of the air funnel, becomes a pulsation of a shifted phase, that is, an intake pulsation of the opposite phase, and returns to the internal combustion engine side. This reflected intake pulsation cancels out intake pulsation from the internal combustion engine side. That is, it is attenuated. Then, only the intake pulsation rectified by the attenuation is directed toward the upstream side of the intake path through the opening at the small diameter end of the air funnel, so that the discharge sound discharged from the intake port of the intake path is reduced.

If the intake pulsation in the opposite phase is generated to attenuate the intake pulsation of the internal combustion engine, the intake pulsation in any frequency range is attenuated.

Therefore, the discharge sound from the intake passage due to the intake pulsation is reduced over the entire frequency range. In particular, in a supercharged engine, supercharging primary (supercharging), supercharging secondary (secondary),.
Since the attenuation is performed for all the order components such as the nth order, the noise level is largely reduced as a whole without taking noise reduction means for each order component.

According to a second aspect of the present invention, there is provided an intake structure for an internal combustion engine.
The air funnel is formed integrally with the outlet of the air cleaner so that the small-diameter end projects first to the outside, and has a fitting portion on the base side with which the intake hose end is fitted. By attaching the end of the intake hose to the insertion portion, the air funnel can be assembled between the air cleaner and the intake hose.

With the structure in which the outlet of the air cleaner also serves as the air funnel, the air funnel can be easily assembled to the intake passage by simply connecting the end of the intake hose to the air cleaner in any intake structure of an internal combustion engine. Moreover, since the air funnel is integrated with the air cleaner, there is no increase in the number of parts.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on a first embodiment shown in FIGS.

FIG. 1A shows an intake system of an internal combustion engine mounted on an automobile. In FIG. 1, reference numeral 1 denotes an internal combustion engine, for example, a reciprocating supercharged engine (hereinafter simply referred to as an engine). In the engine 1, for example, an intake pipe 2, a throttle valve 3, an intercooler 4, and a supercharger 5 (for example, a supercharger driven by the shaft output of the engine 1) are sequentially connected to an intake inlet (not shown) of the engine body. Have been. At the inlet of the supercharger 5, an intake hose 6 and an air cleaner 7 are connected in order, and each component is used to intake air into a section from the intake port 8 at the tip side of the air cleaner 7 to the intake inlet of the engine body. A path 9 is formed. The intake path 9 guides intake air required for combustion from the intake port 8 of the air cleaner 7 to the engine body.

An air funnel 10 which is a main part of the present invention is built in a part of the intake passage 9, for example, between the air cleaner 7 and the intake hose 6. FIG. 1B shows an enlarged portion around the air funnel 10.

The air funnel 10 has, for example, a structure integrated with the air cleaner 7, that is, a structure in which the air funnel 10 itself is used as an outlet port of the air cleaner 7 in consideration of ease of assembly in the intake passage 9. It is.

Specifically, the air funnel 10 is formed by a trumpet-shaped mouth body 11 whose diameter decreases from the upstream side to the downstream side. The mouth 11 has an outer diameter at one end substantially equal to the inner diameter of the intake hose 6 (inner diameter of the intake passage), an outer diameter at the other end smaller than the inner diameter of the intake hose 6, and a length from one end to the other end. It has a trumpet-shaped portion 11b formed in a trumpet shape with an arcuate or straight outer peripheral surface 11a so as to gradually reduce the diameter toward the other end. From the other end of the trumpet-shaped portion 11b, a portion having the same outer diameter and extending linearly is formed, and a receiving portion 11c (corresponding to a fitting portion) into which the intake hose end is fitted is formed. Has formed.

The end of the receiving portion 11c of the air funnel 10 is integrally connected to an outlet 7b formed in the case 7a of the air cleaner 7, and the air funnel 10 is connected to the case 7a.
It is formed integrally with a. That is, air funnel 1
No. 0 is assembled so that the small-diameter end side comes first and projects outside the air cleaner 7. Thereby, the large diameter side of the flared portion 11b of the air funnel 10
The small-diameter end of the flared portion 11b is located downstream of the intake path 9. The receiving part 11c is
Since the air funnel 10 continues to the outer peripheral portion on the base side, the air funnel 10 itself has a structure also serving as an outlet port of the air cleaner 7.

The internal passage 10a of the air funnel 10
As shown in FIG. 1B, for example, an air cleaner 7
Between the outlet 7b and the small-diameter end (including the receiving portion 11c) is formed by a gradually arcuate gentle arc-shaped passage wall. Internal passage 1 having a curvature different from that of outer peripheral surface 11a
With the passage shape of 0a, the intake air taken in from the intake port 8 can be led out of the air cleaner 7 through the air funnel 10 while securing the longest passage distance so as to suppress the pressure loss as much as possible.

As shown in FIG. 2, the end of the intake hose 6 is inserted into the outer peripheral portion of the air funnel 10 protruding from the air cleaner 7, and the intake hose 6 is fastened with a fastener, for example, a hose band (not shown). The hose end is fixed to the receiving portion 11c. By this fixing, FIG.
As shown in FIG. 1, the entire air funnel 10 is assembled in an intake path between the air cleaner 7 and the intake hose 6.

By attaching the air funnel 10 to the intake passage 9 of the engine 1 in this manner, the discharge noise caused by the intake pulsation of the engine 1 and the supercharger 5 can be reduced over the entire frequency range.

That is, if an obstacle is placed in the intake path,
The intake pulsation from the engine toward the intake port of the intake path is reflected by an obstacle, and a pulsation having a shifted phase, that is, an intake pulsation having an opposite phase is generated.

The air funnel 10 has an upstream end of the intake hose 6 as shown in FIG. 1 so that this phenomenon is maximized in the intake passage 9 without causing unnecessary pressure loss. The diameter is substantially the same as the inner diameter, the downstream end is smaller in diameter than the inner diameter of the intake hose 6, and the diameter is gradually reduced toward the downstream side.

That is, when the engine 1 is operated with the air funnel 10 assembled, the intake air taken in from the intake port 8 of the air cleaner 7 is
Air funnel 10, intake hose 6, turbocharger 5,
It is introduced into the engine body through the intercooler 4 and the throttle valve 3, and burns fuel in a predetermined cycle.
Reciprocate the piston.

At this time, since the diameter of the internal passage 10a of the air funnel 10 is gradually reduced by using the full length, the pressure loss is small and the intake air is effectively guided to the engine body.

On the other hand, due to the operation of the engine 1 and the operation of the supercharger 5, intake pulsation accompanying the operation of the engine 1 and intake pulsation (supercharging pulsation) accompanying the operation of the supercharger 5 occur in the intake passage 9.

That is, for example, in FIG.
An intake pulsation A having a waveform as shown in (a) is generated, and travels from the engine 1 toward the intake port 8 of the air cleaner 7.

Here, the air funnel 10 has a small-diameter end opening 12 a at the center of the intake passage 9.
1A is blocked by the outer peripheral surface 11a whose diameter is gradually reduced, of the intake pulsation A reaching the air funnel 10, the intake pulsation A reaching the outer peripheral surface 11a is shown in FIG.
(B) As shown in FIG.
3a, the intake pulsation reflected at a and shifted in phase, that is, FIG.
The pulsation B has the opposite phase as shown in (b) and returns to the engine 1 side. The reflected intake pulsation B cancels the intake pulsation A from the engine 1 side. That is, the intake pulsation A is attenuated and rectified into a small intake pulsation C as shown in FIG. Only the rectified small intake pulsation C is caused by the opening 12a at the small diameter end of the air funnel 10,
Through the internal passage 10a and the opening 12b at the large-diameter end, it reaches the intake port 8 of the air cleaner 7. Thereby, the discharge sound of the intake port 8 is reduced.

With a mechanism for generating the intake pulsation B having the opposite phase to attenuate the intake pulsation A from the engine 1 and the supercharger 5, the attenuation can be performed in any frequency range.

Therefore, the air funnel 10 can reduce the discharge sound of the intake pulsation A in the entire frequency range.

In addition, the damping is caused by the supercharging 1 in the supercharging pulsation (intake pulsation) caused by the supercharging by the supercharger 5.
Since the operation is performed for all order components such as next, supercharged second, supercharged third,..., Nth, etc., the noise level can be largely increased without taking noise reduction means such as an intake resonator for each order component. Can be reduced to

In particular, as the size of the length L (shown in FIG. 1B) of the air funnel 10 becomes longer as shown in the diagram of FIG. Is small,
As shown in the diagram in FIG. 4B, the opening diameter at the small diameter end (the opening 1
0a) is characterized in that the smaller the throttle ratio, the smaller the discharge sound (intake sound). In order to exhibit the maximum noise reduction performance in consideration of the pressure loss, the dimensional relationship of each part is d = 0.6 to 0.5D, and the range of L = 50 to 100 mm was suitable.

FIG. 5 shows a comparison between the discharge sound level of the supercharged engine without the air funnel 10 and the discharge sound level of the supercharged engine with the air funnel 10 at a point close to the intake port 8. It has been confirmed that when the air funnel 10 is mounted in such a manner, the noise can be significantly reduced.

That is, a diagram a shown by a broken line in FIG.
5 shows the discharge sound level from the intake port 8 in the full load state without the air funnel, and is shown by the dashed lines b to k in FIG.
Indicates the ejection sound level of each order component accompanying the supercharging. A solid line diagram A in FIG. 5 shows a discharge sound level from the intake port 8 in a full load state with an air funnel, and solid line diagrams B to K in FIG. The accompanying figure shows the ejection sound level of each order component. As can be seen from a comparison between the broken line diagram and the solid line diagram, the noise level is greatly reduced in the entire discharge sound, and the noise level is also significantly reduced in the discharge sound in each order component region. It is understood that a remarkable noise reduction effect can be obtained only by using the above.

Since the air funnel 10 also serves as the outlet 7b of the air cleaner 7, the air funnel 10 can be easily connected to the intake path of any engine by simply connecting the end of the intake hose to the air cleaner 7. 9 can be assembled. Moreover, since the air funnel 10 is formed integrally with the air cleaner 7, there is no increase in the number of parts and the cost is low.

FIG. 6 shows a second embodiment of the present invention.

FIG. 6 shows a structure in which the air funnel 10 is not integrally formed with the air cleaner 7 but a separate air funnel 10 is integrally assembled with the air cleaner 7.

More specifically, the air funnel 10 is formed as a single unit from the portion having the receiving portion to the small diameter end. More specifically, the air funnel 10 forms the insertion portion 15 at the outer peripheral portion where the receiving portion exists, and the insertion portion 1
A flange-shaped stopper 16 is formed at the boundary between the outer peripheral surface 11a and the outer peripheral surface 11a whose diameter gradually decreases. The outlet 7b of the air cleaner 7 is formed with a fitting opening 17 (fitting portion) projecting to the outside. The air funnel 10 is provided with the fitting 1
7, the insertion portion 15 is inserted until it is positioned by the stopper 16, so that the small-diameter end side is firstly protruded from the outlet 7 b of the air cleaner 7. At this time, the fitting opening 17 is arranged so as to be continuous with the large-diameter end of the outer peripheral surface 11 a, and forms a portion where the end of the intake hose fits in the outer peripheral portion on the root side of the air funnel 10.

In this air funnel 10, the fitting 1
By inserting the end of the intake hose into the outer peripheral surface of the hose 7 and fixing the end of the hose to the fitting 17 with a hose band, the hose can be assembled in the intake path between the air cleaner 7 and the intake hose. An effect similar to that of the first embodiment is obtained.

However, in FIG. 6, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In each of the above-described embodiments, an example is described in which an air funnel is provided in an intake path between an air cleaner and an intake hose. However, the air funnel is not limited to this. However, even in the middle of the intake hose, it may be attached to the part from the end of the intake hose to the engine, as long as it is installed in the intake path from the engine to the intake port of the air cleaner, the same effect as the embodiment described above To play.

In the above-described embodiment, an example in which the air funnel is provided in the intake path of the supercharged engine has been described. However, even if the air funnel is provided in the intake path of the engine without the supercharger, that is, the naturally aspirated engine, Similarly, the noise from the air cleaner can be significantly reduced.

[0047]

As described above, according to the first aspect of the present invention, the intake pulsation of the internal combustion engine is canceled by generating the intake pulsation of the opposite phase by using the air funnel. It can also attenuate intake pulsation in a wide frequency range.

Accordingly, with a relatively simple configuration, it is possible to reduce the discharge sound (noise) from the intake passage due to the intake pulsation over the entire frequency range.

According to the second aspect of the present invention, since the outlet of the air cleaner also serves as an air funnel, any intake structure of an internal combustion engine can be simply constructed by connecting the end of the intake hose to the air cleaner. The air funnel can be assembled to the intake path. Moreover, since the air funnel is formed integrally with the air cleaner,
There is no increase in the number of parts and the cost is low.

[Brief description of the drawings]

FIG. 1A is a schematic diagram illustrating an intake structure of an internal combustion engine according to a first embodiment of the present invention. (B) is a figure which expands and shows the structure around the air funnel of the said intake structure.

FIG. 2 is a view for explaining a structure in which an air funnel integrated with an air cleaner is assembled with an intake hose.

FIG. 3 is a diagram for explaining that intake pulsation from an internal combustion engine and pulsation reflected from an air funnel cancel each other out and are attenuated to small pulsation.

FIG. 4 is a diagram for explaining the size of each part where the noise reduction effect of the air funnel is effectively exhibited.

FIG. 5 is a diagram showing a comparison of discharge noise from an air cleaner with and without an air funnel when the engine is operated under a full load condition.

FIG. 6 is a view for explaining main parts according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine) 5 ... Supercharger 6 ... Intake hose 7 ... Air cleaner 7b ... Outlet 8 ... Intake port 9 ... Intake path 10 ... Air funnel 11a ... Outer peripheral surface gradually reduced in diameter 11b ... Trump-shaped part 11c ... Receiving part (insertion part).

Claims (2)

[Claims] 1. An air intake passage of an internal combustion engine, wherein an upstream end has substantially the same diameter as the inside diameter of the intake passage, and a downstream end has a shape smaller in diameter than the inside diameter of the intake passage and gradually reduced in diameter toward the downstream side. An intake structure for an internal combustion engine, comprising a funnel. 2. The air intake path is formed having an air cleaner and an intake hose connected to the air cleaner. The air funnel is provided at an outlet of the air cleaner.
A small diameter end side is integrally formed so as to protrude to the outside first, and is formed with a fitting portion on the base side where the intake hose end fits, by attaching the intake hose end to the fitting portion. 2. The intake structure for an internal combustion engine according to claim 1, wherein the air funnel is assembled between the air cleaner and the intake hose.