JPS63219866A - Intake device for internal combustion engine - Google Patents

Abstract

PURPOSE:To promote the reduction of intake noise by using only the first air duct, when an engine is in a low load operation region, and the improvement of an output by using both ducts when the engine is in a high load operation region, by dividing the air duct into the first duct and the second duct. CONSTITUTION:When an engine is in a low load operation region, a secondary throttle valve 13 is closed, and air from an air cleaner 7 is supplied to an intake port 1 via the first air duct 5, primary passage 10, intake package 3 and each intake pipe 2. When the engine is in a high load operation region, both the throttle valves 12, 13 are opened, and air from the air cleaner is supplied to the intake port 1 of an engine main unit E via the first and second air ducts 5, 6, primary and secondary passages 10, 11, intake package 3 and each intake pipe 2.

Description

Detailed Description of the Invention A0 Object of the Invention (11 Industrial Application Fields) The present invention provides a throttle body connected to an outlet of an air cleaner via an air duct, the throttle body having the following features:
The primary passageway has a primary throttle valve that opens and closes in the engine's low-load operating range, and the secondary passageway has a secondary throttle valve that opens and closes in the engine's high-load operating range. The present invention relates to an independently provided intake system for an internal combustion engine.

(2) Prior Art Conventionally, such an intake device has been used, for example, in U.S. Pat.
It is publicly known from Publication No. 34 and the like.

(3) Problems to be Solved by the Invention Incidentally, in order to improve the output of an engine, it is common practice to increase the inner diameter of the air duct as much as possible to reduce suction resistance. However, in the conventional system described above, since the throttle body and the air cleaner are connected by a single air duct, intake noise inevitably increases as the inner diameter increases. In other words, when the air flows from the air cleaner to the air duct, intake noise is reduced due to the throttling effect caused by the small cross-sectional area of the flow, but in the case of a single air duct, the inner diameter must be made relatively large to cope with the increase in output as described above. Since this is unavoidable, a sufficient aperture effect cannot be achieved.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an intake system for an internal combustion engine that satisfies both the improvement of engine output and the reduction of intake noise.

B1 Structure of the Invention (1) Means for Solving Problems According to the present invention, the air duct includes a first air duct that connects the passenger passage and the air cleaner, and a secondary passage and the air cleaner independently of the first air duct. and a second air duct connecting the air duct.

(2) Effect According to the above configuration, in the low-load operating range of the 10 engines, air flows only through the -passageway and the first air tally to reduce intake noise, and in the high-load operating range of the engine, - Output can be improved by allowing air to flow through both the passageway and the first air duct, as well as the secondary passageway and the second air duct.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. An intake pipe 2 is connected to each intake boat 1 in the engine body E of a multi-cylinder, for example, four-cylinder internal combustion engine, and each intake The upstream end of the pipe 2 is connected to an intake surface 3 common to each cylinder. Further, at the inlet of the intake surface 3, there is a common throttle body 4 and a first throttle body. The lower outlet a and 7a of the air cleaner 7 are connected through the second air duct 5.6, and the lower inlet b of the air cleaner 7 is opened to the atmosphere through the intake tube 8 and the suction pipe 9.

The throttle body 4 is provided with a primary passage 10 and a secondary passage 11 that are connected to each other in the intake surface 3 and are provided independently from each other.
A primary throttle valve 12 is provided in the passenger passageway 1o, and a secondary throttle valve 13 is provided in the secondary passageway 11. Both throttle valves 12 and 13 are driven to open and close in response to throttle operation, and after the secondary throttle valve 12 opens to the desired opening degree, the secondary throttle valve 13 begins to open.

Therefore, in the engine's low-load operating range, air flows only through the primary passage 1°, and in the engine's high-load operating range, air flows through both roads at 10.1°.
Air flows through both.

The first and second air ducts 5 and 6 are bent and formed of, for example, synthetic resin, and one ends thereof are connected to the throttle body 4 so as to communicate with the primary passage 10 and the secondary passage 11 individually. Moreover, the inner diameter d1 of the first air duct 5 is set smaller than the inner diameter of a single work duct that has been used conventionally.

The other ends of the first and second air ducts 5.6 are connected to the bellows pipe 14.
．． 15, respectively, to the air cleaner 7 outlet lower a, 7.
a, respectively. The intake tube 8 is made of, for example, synthetic resin, and the sum of the inner diameters di and d2 of the air ducts 5 and 6 is set to be greater than the inner diameter of the intake tube 8 (dl+d2≧D).

Next, to explain the operation of this embodiment, in the low load operating range of the engine, the secondary throttle valve 13 is closed, and the air from the air cleaner 7 is passed through the first air ducts 5, -
It is supplied to the intake boat 1 of the engine body E through the man passage 10, the intake surface 3, and each intake pipe 2. At this time, since the inner diameter d1 of the first air duct 5 is set smaller than that of the conventional one, the first air duct 5 between the air intake surface 3 and the air cleaner 7, which functions as a noise reduction chamber, can sufficiently exert a throttling effect. The silencing effect can be enhanced, and as the duct surface area is reduced, transmitted sound can be suppressed, and in conjunction with this, intake noise can be reduced.

In addition, when the engine is in a high-load operating range, both throttle valves 12 and 13 are open, and air from the air cleaner 7 is pumped through the first and second air ducts 5, 6, secondary and secondary passages 10 and 11, and the intake air. It is supplied to the intake port of the engine body E via the surface 3 and each intake pipe 2. At this time, ct1+
Since d2≧D, both air ducts 5.6 can be arranged more freely than when a single air duct is provided.
Furthermore, the suction resistance in both air ducts 5 and 6 can be kept relatively low, contributing to an increase in output.

C9 Effects of the Invention As described above, according to the present invention, the air duct includes a first air duct that connects the primary passage and the air cleaner, and a second air duct that connects the secondary passage and the air cleaner independently of the first air duct. Since it is divided, only the first air duct can be used to reduce intake noise in a low engine load operating range, and both air ducts can be used to improve output in a high engine load operating range.

[Brief explanation of the drawing]

The drawing is a partially cutaway plan view of an embodiment of the present invention. 4... Throttle body, 5... First air duct,
6...Second air duct, 7...Air cleaner, 7a
...Outlet, 10...Primary passage, 11...Secondary passage, 12゜13...Throttle valve

Claims (1)

[Claims] A throttle body is connected to the outlet of the air cleaner via an air duct, and the throttle body has a primary passage in which a primary throttle valve that opens and closes in the engine's low-load operating range and a primary passage that opens and closes in the engine's high-load operating range. In an intake system for an internal combustion engine in which a secondary passage in which a secondary throttle valve that is opened and closed is disposed in the middle is provided independently from each other, the air duct includes a first duct that connects the primary passage and the air cleaner, and a first duct that connects the primary passage and the air cleaner. An intake system for an internal combustion engine, characterized in that the air intake system is divided into a secondary passage and a second duct that connects an air cleaner.