JPS6093123A - Intake device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To previously avoid generation of noise due to a back flow of pressurized air at the time a throttle valve is completely closed during supercharging operation by arranging a muffler in an intake path on upper stream side from an impeller. CONSTITUTION:At the time of supercharging operation of an engine 1, the impeller 14 of a turbo charger 4 rotates with high speed (for example, 100,000rpm), compresses intake air, and supercharges it to a cylinder 12. And when a throttle valve 13 is rapidly closed, air of high pressure in an intake path 11 which is on the upper stream from the throttle valve 13 and on the lower stream from the impeller 14 flows backward as it expands to the inside of the intake path 11 which is on the upper stream side from the impeller 14 of low pressure (approximately the atmospheric pressure), and it generates noise of 200Hz-2kHz. This noise can be silenced by a muffler 20 which is arranged in the intake part 11.

Description

Detailed Description of the Invention (Technical Field) This invention relates to an internal combustion engine, particularly an internal combustion engine with a supercharger, in which an impeller (τJ impresor sapoir) is interposed in the intake passage on the upstream side of the throttle valve 1. Concerning improvements to equipment.

(Prior Art) As a conventional intake system for an internal combustion engine with a supercharger, for example, the one disclosed in Japanese Patent Application Laid-open No. 1983 G] 4! The one described in Publication No. 315 is known. This intake system has a turbocharger impeller installed upstream of the throttle valve in the five intake circuits.The intake air taken in through the air cleaner is measured with a hot-wire airflow meter, and the impeller After being compressed, each cylinder is supercharged from the intake manifold 1-' via a throttle valve.

However, in such conventional intake devices,
Intake passage between air cleaner and impeller 14J
It is formed by an intake pipe with an area of approximately -. Therefore, when the throttle valve is suddenly closed during supercharging, the compressed air between the throttle valve and the impeller flows back into the intake passage upstream of the impeller. This causes a problem in that the noise is radiated outside from the air intake port of the air cleaner, resulting in unpleasant noise.

(Objective of the Invention) Therefore, it is an object of the present invention to solve the above problems by disposing a muffler in the intake passage on the upstream side of the impeller.

(Structure of the Invention) The present invention provides an intake system for an internal combustion engine in which an impeller of a supercharger is interposed in an intake passage upstream of a throttle valve. It has an arranged configuration.

(Example) Embodiments of the present invention will be described below based on the drawings.

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a schematic diagram showing the entire intake system, FIG. 2 is a sectional view of a silencer, and FIG. ITI-FIT arrow view, 4th
The figure shows the air intake system mounted on the vehicle -4-) (' ii
In the figure, the 51st part 1 is a view of the 41st part 1 in the direction of the ■ arrow.

In Fig. 1, ]+;・On the 5th side, connect the intake manifold I・'6, su1kottorusen, tonpuff, impeller housing 8, posotowa □i -1□ jC AB 11 meter body 9 and air cleaner, J-IQ -ζ intake air is supplied into each cylinder 12 through an intake passage 11 formed inside these cylinders.
1. The throttle valve installed in the sole chamber 7 is installed in the 14 cylinder housing sink.
Reference numeral 5 indicates a hot wire type air flow meter installed in the body 1], and 7 indicates a hot wire type air flow meter. In addition, the intake passage 11
The cross-sectional area of the passage excluding the air cleaner 10 and the impeller housing 8 is approximately uniform and circular. Here, a muffler 20 is interposed on the flow side of the impeller 14 of the intake passage 11 and on the downstream side of the air flow meter 15. This muffler 20, as shown in detail in FIGS. 2 and 3,
A large-capacity expansion chamber 22 (having a cross-sectional area larger than the cross-sectional area of the intake passage I) is formed by a cylindrical housing 21 made of resin.
A tapered cylindrical upstream pipe 23 is provided in the expansion chamber 22.
and a cylindrical downstream pipe 24 protrude and face each other. The upstream end of this upstream pipe 23 is connected to the body 9 of the air flow meter via an elastically deformable tube 25, and the downstream end of the downstream pipe 24 is similarly connected to the impeller housing 8 via a flexible tube 26, etc. has been done. That is, the upstream pipe (inlet pipe) 23 is connected to the silencer 2
A downstream pipe (outlet pipe) 24 is installed in the intake passage 11 on the upstream side of 0.
are connected to the intake passage 11 on the downstream side of the muffler 20, respectively. Further, the upstream pipe 23 and the downstream pipe 24 are arranged coaxially and face each other at a predetermined distance within the expansion chamber 22. That is, the upstream pipe 23
and each opening 23A of the downstream pipe 24 into the expansion chamber 22,
24A (the downstream end opening 23A of the upstream pipe 23 and the upstream end opening 24A of the downstream pipe 24) are opposed to each other with a predetermined interval apart, and this interval I7 is the distance between these circular openings 23A, 24.
Diameter of A (these lines i\DO1D are approximately equal l, ))
It is set almost the same as DD, D (Do#Dt#17
). The end of the flow tube 23 that protrudes into the expansion chamber 22 has a slope of a predetermined angle θ and has a continuous diameter of 111 (with a tapered shape toward the downstream side). ). Further, the axes of the upstream pipe 23 and the downstream pipe 24 are also made to coincide with the axis of the nozzing 21. Furthermore, on the outside of this silencer 20 (a resin housing 2
A heat shield plate 30 made of metal, for example, is attached by a support boss 21A so as to cover the front surface of the housing 21, as shown in FIG. Cover approximately 1/4 of the area with Oshi A in the circumferential direction of '+4. m
It is fixed to the housing 21 with a predetermined gap from the A side.

Figures 4 and 5 show the air intake system mounted on the vehicle (with the engine 1 placed horizontally). A heat shield plate 30 for blocking radiant heat covers the lower rear side of the silencer 20 facing outward. Further, an electric fan 31 is disposed in front of the radiator 20 to guide cold air from the radiator 32 into the gap between the heat shield plate 30 and the outer surface of the housing 21.

In FIG. 1, numeral 35 indicates a turbine wheel, and numeral 36 indicates a swing valve (exhaust bypass valve).

Next, the effect will be explained.

During supercharging operation of the engine 1, the impeller 14 of the turbocharger 4 rotates at high speed (for example, 100.00 Or, p
, m) to compress the intake air and supercharge the cylinder 12.

At this time, when the throttle valve 13 is suddenly closed (such as during sudden braking), the high pressure air in the intake passage 11 upstream of the throttle valve 13 and downstream of the impeller 14 is transferred to the impeller 14 at a low pressure (approximately atmospheric pressure).
The air flows backward while expanding into the intake passage 11 on the more upstream side, and 2
Generates noise between 00 Hz and 2 KHz. This noise cannot be muffled in the conventional air intake system using only an air cleaner and is dissipated to the outside, but in the present invention, it can be muffled by the muffler 20.

That is, the high-pressure air that flows backward flows into the expansion chamber 22.
C expands, the pressure decreases, and in a predetermined frequency range, each time it resonates, the sound is muffled. In particular, since the silencer 20 has the above-mentioned structure in which the upstream pipe 23 and the downstream pipe 24 are inserted into the expansion chamber 22 and penetrated in one direction, noise can be generated over a wide range from 20011z to 2Kllz. . In addition, in the case of the 1-note booklet 20, the downstream end of the upstream pipe 23 is formed into a tapered shape 7, so that the flow velocity of the intake air increases and the intake air smoothly flows into the opposing downstream pipe 24 without being diffused. The increase in inhalation resistance is extremely small. In addition, a heat shield plate 30 is provided on one side of the silencer 20, and a gap is formed between the outer surface of the silencer 20 and the heat shield plate 30 that opens toward the front of the vehicle. The cooling effect is increased, and radiant heat from each part of the engine or the exhaust system 3 can be completely blocked.

As for the structure of the silencer, in the present invention, it is also possible to use a resonance type or a sound absorbing type, as well as a combination of these, instead of the expansion type described above. (,1 Needless to say.

(Effects) As described above, according to the present invention, it is possible to prevent noise generation due to backflow of pressurized air when the throttle valve is fully closed during supercharging operation.

Further, in the above embodiment, it is possible to prevent malfunction of the true wire type air flow meter due to backflow of intake air, and to obtain a noise reduction effect over a wide range. In addition, the silencer's housing is made of resin, making it lightweight, and the addition of a heat shield and cooling fan completely prevents heat effects when installed in a vehicle.

[Brief explanation of drawings]

1 to 5 show an embodiment of an intake system for an internal combustion engine according to the present invention, FIG. 1 is a schematic overall configuration diagram thereof, FIG. Figure 3 shows r in Figure 2.
Fig. 4 is a plan view of the same device when mounted on a vehicle;
The figure is a view taken in the direction of the V arrow in FIG. 4. 4------1 supercharger, 11-----1 intake passage, 13-----throttle valve, 14 impeller, 20-silencer. Patent applicant: Nissan Motor Co., Ltd. Representative patent attorney: Arigagun Part 0

Claims (2)

[Claims] (1) An intake system for an internal combustion engine in which an impeller of a supercharger is interposed in an intake passage upstream of a throttle valve, characterized in that a muffler is disposed in the intake passage upstream of the impeller. Intake device. (2) The silencer includes an expansion chamber having a larger cross-sectional area than the intake passage, a tapered cylindrical upstream pipe that communicates with the intake passage on the upstream side of the silencer and projects into the expansion chamber, and an upstream pipe on the downstream side of the silencer. a cylindrical downstream pipe that communicates with the intake passage and projects into the expansion chamber and has an upstream end opening that has approximately the same diameter as the downstream end opening of the upstream pipe, and the upstream pipe and the downstream pipe are connected to the downstream end. An intake device for an internal combustion engine according to claim 1, which is arranged coaxially with a distance of approximately the same length as the diameter of the opening.