JPS6161910A - Air cleaner for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve volume efficiency of an internal-combustion engine by providing air passages having different length each other and a switch valve changing over respective air passages in correspondence with the rotating number of the internal-combustion engine without providing plural suction pipes of different length. CONSTITUTION:A valve 10 is forwarded by a spring 12 till an internal-combustion engine 11 attains a predetermined rotating number. And the air flowed from a suction port 3 is passing through a filter element 2 and fed to the internal-combustion engine 11 from an opening 7 through an air passage B and an exhaust port 9. While when the internal-combustion engine attains the predetermined rotating number, a valve 13 is opened by a control unit 14 and the valve 10 is retired by negative pressure of an intake manifold. Then, the air passage B is closed to open an air passage A. The air flowed from A is fed to the internal-combustion engine from the opening 8 through the exhaust port 9. This time, an opening 7 is always opened, so the volume held by the air passage B is utilized for sound arresting, attached function of an air cleaner.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air cleaner for an internal combustion engine, and more particularly to an air cleaner for an internal combustion engine for an automobile.

[Prior art]

It is obvious that by continuously changing the length of the intake pipe of an internal combustion engine, the natural frequency of the intake pipe is made proportional to the rotational speed of the internal combustion engine, thereby increasing the volumetric efficiency of the engine over a wide rotational range.

Various techniques for switching the length of the intake pipe in two stages instead of continuously changing the length of the intake pipe have also been disclosed. For example, in Japanese Utility Model Application Publication No. 56-2021, the lengths of the plurality of intake pipes are formed to be approximately equal, a short branch pipe is provided in the middle of the intake pipe, and the intake pipes are connected to the intake pipes and the branch pipes. A technique is disclosed in which a branch pipe section is provided with a switching valve that opens and closes each passage in accordance with the rotational speed of the internal combustion engine, and an intake silencer box is further provided in which the branch pipe and switching valve are housed.

Further, in Japanese Utility Model Application Publication No. 56-67326, a plurality of intake pipes of different lengths are provided for each intake boat of an internal combustion engine, and the intake pipe of any one of the intake pipes is provided with a plurality of intake pipes of different lengths depending on the rotational speed of the internal combustion engine. Techniques have been disclosed that have switching valves to switch the use of pipes.

These systems require a large installation space, such as installing a noise reduction box and providing intake pipes of different lengths for each intake port of the engine, and have drawbacks such as requiring a large number of parts. In particular, the use of internal combustion engines for automobiles, which are subject to severe space restrictions, is accompanied by many problems and costs are relatively high.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide an air cleaner for an internal combustion engine that can obtain the same effect without changing the length of the intake pipe of the internal combustion engine.

[Structure of the invention]

The present invention forms air passages of different lengths and a switching valve for switching the air passages in an air purifier, and switches the switching valve according to the rotational speed of the internal combustion engine to improve the volumetric efficiency of intake of the internal combustion engine. −
This makes it possible.

〔Example〕

Reference numeral 1 designates a cup-shaped case in which a filter element 2 is housed. The case 1 has an intake port 3 formed on its side for sucking in outside air, and a cap 4 that removably engages with the case 1 is locked therein. A partition plate 5 is attached to the cap 4 so as to partition the space inside the case 1 and the space inside the cap 4, and the partition plate 5 has a partition wall 6 that cooperates with the cap 4 to form an air passage B. An opening 7 opening into the air passage B and an opening 8 forming the air passage A are provided. The cap 4 is connected to the internal combustion engine 11 through a duct (not shown), and has an exhaust port 9 and a valve 10 for opening and closing the air passages A and B.
The valve 10 is normally biased by a compression spring 12 to the position shown in solid lines in FIG. 1, closing the opening 8.

Valve 10 is connected to the intake manifold via valve 13. 14 is a control unit that controls the square 13. Air passing through the air passage A passes from the filter element 2 through the opening 8 and reaches the internal combustion engine 11 via the exhaust port 9; air passing through the air passage B passes from the filter element 2 through the opening 7; It passes through a passage defined by the partition wall 6 and reaches the internal combustion engine 11 from the same exhaust port 9. That is, the air passage A has a shorter length than the air passage B.

Next, the operation will be explained.

From the start of the internal combustion engine 11 until it reaches a predetermined rotational speed n, the square 10 is biased to the solid line position in FIG. The air flows from the opening I through the air passage B and from the exhaust port 9 to the internal combustion engine 11.

When the rotation speed of the internal combustion engine reaches the predetermined rotation speed n, the control unit 1
A signal from 4 opens valve 13, directs the negative pressure in the intake manifold to valve 10, and moves valve 10 to the position shown in broken line in FIG. As a result, air passage B is closed,
Air passage A is opened. As a result, air flowing in through the intake port 3 passes through the filter element 2, reaches the exhaust port 9 through the opening 8, and flows into the internal combustion engine 11. Since the air passage B is closed but the opening 7 is always open, the volume held by the air passage B can be used for noise reduction, which is an additional function of the air purifier.

When the rotational speed of the internal combustion engine 110 falls below the predetermined value n, the valve 13 is closed in response to a signal from the control section 14 to cut off the negative pressure in the intake manifold, and the valve 10 is returned to the position shown in the solid line in FIG. As a result, air passage A is closed and air passage B is opened.

The effect obtained from the above operation is as shown in Figure 3, where curves A and 2 are obtained, where the volumetric efficiency peaks in the low and high rotation ranges, and curves A and 2 are connected at the position of a predetermined rotation speed n. Obtain the curve for the volumetric efficiency of the internal combustion engine. As a result, the output of the internal combustion engine is leveled out at a high level. The broken line C in FIG. 3 shows the volumetric efficiency when there is no switching function between the air passages A and B, but as is clear from FIG. 6, the volumetric efficiency of the present invention does not have the switching function between the air passages. It shows higher efficiency.

In the embodiment, the air passages A and B are formed between the exhaust port 9 and the filter elements 2 and 8, but they may also be formed between the intake port 3 and the filter element 2.

Moreover, although the negative pressure of the intake manifold is used to operate the valve 10, it goes without saying that a normal lenoid may be used.

〔Effect of the invention〕

According to the present invention, there is provided an air purifier that allows an internal combustion engine to exhibit volumetric efficiency equivalent to that of an internal combustion engine having an intake pipe switching function without providing a plurality of intake pipes of different lengths for each intake port of the internal combustion engine. provided. Further, since it is not necessary to provide a plurality of intake pipes, a silencer box, etc. to the internal combustion engine, the number of parts can be reduced, and the installation space can also be reduced.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of the air purifier according to the present invention, Fig. 2 is a cross-sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is an internal combustion engine using the air purifier according to the present invention. FIG. 2 is a characteristic diagram showing the volumetric efficiency of A...Air passage, B...Air passage, 10...Switching valve.

Claims (1)

[Scope of Claim] An air cleaner for an internal combustion engine, comprising: air passages having different lengths; and a switching valve that switches the air passages in accordance with the rotational speed of the internal combustion engine.