JPS6146204Y2 - - Google Patents

Description

[Detailed description of the invention] A. Purpose of the invention (1) Industrial application field The invention is an air cleaner for an internal combustion engine that supplies clean air to the carburetor of the internal combustion engine and extracts secondary air for exhaust purification. Regarding.

(2) Prior Art Conventionally, in the air cleaner, in addition to opening the intake passage of the carburetor into the clean air chamber inside the air cleaner,
The discharge end of the blow-by gas recirculation passage communicating with the crank chamber of the internal combustion engine is connected to the suction end of the secondary air take-off passage communicating with the exhaust system of the engine, so that the blow-by gas in the crank chamber is removed during operation of the internal combustion engine. The blow-by gas is sucked into the clean air chamber through the recirculation passage, the clean air is introduced into the carburetor together with the blow-by gas, and a part of the clean air in the clean air chamber is then exhausted from the internal combustion engine through the secondary air take-out passage. There are known devices that allow it to be introduced into a system. However, since blow-by gas contains a large amount of fuel vapor, oil mist, moisture, etc., it is not only unsuitable as secondary air for exhaust purification, but also when this blow-by gas flows into the secondary air passage for exhaust purification, These particles adhere to and accumulate on the pipe wall of the passageway, gradually narrowing the passageway and reducing the amount of intake air, resulting in a problem that prevents securing the necessary amount of secondary air over a long period of time.

Therefore, in order to avoid the mixing of the blow-by gas and the secondary air for exhaust gas purification in the clean air chamber of the air cleaner and eliminate the above-mentioned problem, a blow-by gas recirculation passage is The discharge end and the suction end of the secondary air take-out passage may be separated from each other to open into the clean air chamber, or the blow-by gas may be caused to flow within the clean air chamber by a partition wall as shown in Japanese Utility Model Publication No. 13445/1983. Conventionally, it has been proposed to divide the exhaust gas into a chamber and a chamber through which secondary air for exhaust gas purification flows.

(3) Problems to be solved by the invention Even if the discharge end of the blow-by gas return passage and the suction end of the secondary air take-out passage are simply separated, if there is no shield between them, the blow-by gas in the clean air chamber will be removed. It is not possible to effectively prevent the mixture of the secondary air and the secondary air for exhaust gas purification.

Furthermore, if the partition wall is specially provided in the clean air chamber,
Not only does the structure of the air cleaner become complicated,
Another drawback is that the effective passage area for clean air in the clean air chamber is reduced, increasing the flow resistance of clean air to the vaporizer.

SUMMARY OF THE INVENTION An object of the present invention is to provide an air cleaner for an internal combustion engine that can eliminate all of the above-mentioned problems of the prior art.

B. Structure of the invention (1) Means for solving the problem The invention consists of an unpurified air chamber that communicates with the atmosphere through a cleaner element inside the air cleaner case, and a clean air chamber that communicates with the intake path of the carburetor. and a discharge end of a blow-by gas recirculation passage communicating with the crankcase of the internal combustion engine and a suction end of a secondary air take-off passage communicating with the exhaust system of the internal combustion engine are respectively opened in the clean air chamber. In the air cleaner for an internal combustion engine, the cleaner element is formed into a hollow cylindrical shape, the unpurified air chamber is formed in the hollow part, and the air cleaner case surrounding the cleaner element and the outer periphery thereof is provided. defining the annular clean air chamber;
A discharge end of the blow-by gas recirculation passage and an intake passage communicating with the intake passage of the carburetor are opened at one side of the clean air chamber, and
A suction end of the secondary air take-off passage is opened on the other side with the cleaner element in between.

(2) Effect Since the cleaner element can be used as a shielding member to block a large area between the discharge end of the blow-by gas recirculation passage and the suction end of the secondary air take-off passage within the cleaner case, the shielding effect of the cleaner element can be improved. , and the passage extension effect between the discharge end and the suction end, it is possible to very effectively prevent the blow-by gas that has flowed into the clean air chamber from the discharge end from flowing toward the suction end.

Moreover, since the discharge end of the blow-by gas recirculation passage and the intake passage opening leading to the carburetor intake passage can be arranged close to each other, after passing through the cleaner element, the intake passage opening can be opened by bypassing the outer circumference of the cleaner element. The suction end of the secondary air take-out passage can be located at the upstream side of the flow path for clean air flowing toward the flow, and the discharge end of the blow-by gas recirculation passage can be positioned at the downstream side thereof, so that the blow-by gas is directed to the suction end side. can more effectively prevent the flow of

(3) Embodiment Next, a first embodiment of the air cleaner of the present invention will be described with reference to FIG. _1. A hollow cylindrical cleaner element ₂₁ is accommodated in a cleaner case ₁₁ of the air cleaner. The interior of the cleaner case ₁₁ is an unpurified air chamber corresponding to the hollow part of the cleaner element ₂₁ .
A ₁ and an annular clean air chamber B ₁ that surrounds the outer periphery of the cleaner element 2 ₁ , and the upper part of the unpurified air chamber A ₁ communicates with an atmosphere introduction passage 3 ₁ that opens to the atmosphere. .

In addition, on one side of clean air chamber _B1 , there is a
Intake path 4 ₁ leading to the intake path of a carburetor (not shown)
However, discharge ends 5a ₁ of blow-by gas recirculation passages 5 ₁ communicating with an engine crankcase (not shown) are opened at the bottom thereof. The discharge end 5a ₁ of the blow-by gas recirculation passage 5 ₁ is provided on the outer circumferential wall of the expansion chamber 7 ₁ formed directly below the cleaner element 2 ₁ in the cleaner case 1 ₁ , and is located at the entrance of the expansion chamber 7 ₁ . 8 ₁ is connected to a rubber tube portion of a blow-by gas recirculation passage 5 ₁ that penetrates the outer circumferential wall of the cleaner case 1 ₁ and crosses the clean air chamber B ₁ .

On the other hand, a suction end 6a _{1 of a secondary air take-off passage 6 1 connected} to an engine exhaust system (not shown) is opened at the other end _of the clean air chamber B ₁ across the cleaner element 2 1 .

Next, to explain the operation of the first embodiment, when the internal combustion engine is operated, the atmospheric air is introduced by the negative intake pressure generated in the intake passage ₄₁ as shown by the double line arrow in FIG. Passage 3 Unpurified air chamber from ₁
After flowing into A ₁ , it passes through the cleaner element 2 ₁ and flows into the intake passage 4 ₁ through the clean air chamber B ₁ . Further, the blow-by gas passes through the expansion chamber ₇₁ , flows into the clean air chamber _B1 from the recirculation passage discharge end _5a1 as shown by the solid arrow, merges with the clean air, and flows into the intake passage ₄₁ . On the other hand, a part _of the clean air is transferred to the suction end 6a 1 of the secondary air take-out passage 6 ₁ as shown by the chain arrow in FIG.
The gas is then sucked into the passage ₆₁ , from where it is guided to the exhaust system and used for exhaust gas purification.

Therefore, the discharge end 5 of the blow-by gas recirculation passage ₅₁
Since the cleaner element ₂₁ is largely obstructed between the suction end _6a1 of the secondary air take-off passage ₆₁ , _the blow-by gas discharged from the discharge end _5a1 to the clean air chamber _B1 is blocked. The flow toward the suction end _6a1 side can be effectively prevented. Further, after passing through the cleaner element 2 ₁ , the clean air flow bypasses the outer circumference of the element 2 ₁ and heads toward the opening of the air intake passage 4 _1. The suction end 6a of the secondary air extraction passage 6 ₁ is placed at the upstream side of the flow passage. ₁ , the discharge ends 5a ₁ of the blow-by gas recirculation passages 5 ₁ are located downstream thereof, so that the blow-by gas flows toward the suction end 6 a ₁ by utilizing the flow pressure of the clean air flow. can be effectively prevented.

FIG. 2 shows a second embodiment of the present invention, in which blow-by gas recirculation passage 5
The structure of _{No. 2} is different from the first embodiment. That is, the blow-by gas recirculation passage ₅₂ is connected to the cleaner case _12.
The expansion chamber ₇₂ is inserted into the clean air chamber _B2 from the upper wall and extends downward, directly below the cleaner element ₂₂ .
The expansion chamber ₇₂ is connected to the inlet ₈₂ of the expansion chamber 72.

Therefore, the unpurified air chamber A ₂ is introduced from the atmosphere introduction passage 3 ₂ .
The air flowing into the interior passes through _the cleaner element ₂₂ , as shown by the _double line arrow in FIG. Then, the air flows into the clean air chamber _B2 from the expansion chamber ₇₂ , merges with the clean air, and flows into the intake path ₄₂ .

C. Effects of the invention As described above, according to the invention, the inside of the air cleaner case is divided by the cleaner element into an unpurified air chamber communicating with the atmosphere and a clean air chamber communicating with the intake path of the carburetor. In the clean air room,
In an air cleaner for an internal combustion engine, the discharge end of a blow-by gas recirculation passage communicating with the crankcase of the internal combustion engine and the suction end of a secondary air take-off passage communicating with the exhaust system of the internal combustion engine are each opened,
The cleaner element is formed into a hollow cylindrical shape,
The unpurified air chamber is formed in the hollow part, and the annular clean air chamber is defined between the cleaner element and the air cleaner case surrounding the outer periphery thereof, and one side of the clean air chamber is defined. The discharge end of the blow-by gas recirculation passage is opened in the cleaner case, and the suction end of the secondary air take-out passage is opened in the other side of the clean air chamber across the cleaner element. A cleaner element can be largely blocked as a shielding member between the discharge end of the blow-by gas recirculation passage and the suction end of the secondary air take-off passage;
Due to its shielding effect and the effect of extending the passage between the discharge end and the suction end, it is possible to extremely effectively prevent the blow-by gas that has flowed into the clean air chamber from the discharge end from flowing toward the suction end. Moreover, by using the cleaner element as the above-mentioned shielding member, the structure of the device can be simplified, contributing to cost reduction, and since the cleaner element itself is a component of the air cleaner, Even if this is made to function as the above-mentioned shielding member, it does not impede the smooth flow of intake air inside the air cleaner.

Furthermore, the intake passage leading to the carburetor intake passage is also opened in the one side of the clean air chamber where the discharge end of the blow-by gas recirculation passage opens, so that after passing through the cleaner element, the air intake passage is bypassed around the outer circumference of the cleaner element. In this way, the suction end of the secondary air take-off passage can be positioned at the upstream end of the flow passage for clean air flowing toward the intake passage opening, and the discharge end of the blow-by gas recirculation passage can be positioned at the downstream end thereof. Therefore, by using the flow pressure of the clean air flow, it is possible to more effectively prevent the blow-by gas from flowing from the discharge end to the suction end. Even without special partition walls like
It is possible to reliably prevent blow-by gas from flowing into the secondary air extraction passage, and a sufficient amount of clean air can always be introduced into the secondary air extraction passage.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view of a first embodiment of the air cleaner of the present invention, and FIG. 2 is a longitudinal sectional side view of the second embodiment. A ₁ , A ₂ ... Unpurified air chamber, B ₁ , B ₂ ... Clean air chamber, 1 ₁ , 1 ₂ ... Cleaner case, 2 ₁ , 2
₂ ... Cleaner element, 4 ₁ , 4 ₂ ... Intake passage, 5 ₁ , 5 ₂ ... Blow-by gas recirculation passage, 5
a ₁ , 5a ₂ ...discharge end, 6 ₁ , 6 ₂ ... secondary air take-off passage, 6a ₁ , 6a ₂ ... suction end.

Claims (1)

[Scope of utility model registration request] The inside of the air cleaner case is divided by a cleaner element into an unpurified air chamber that communicates with the atmosphere and a clean air chamber that communicates with the intake path of the carburetor, and the clean air chamber communicates with the crankcase of the internal combustion engine. In an air cleaner for an internal combustion engine, the discharge end of a blow-by gas recirculation passage and the suction end of a secondary air take-off passage communicating with an exhaust system of the internal combustion engine are respectively opened, and the cleaner element is formed into a hollow cylindrical shape. The unpurified air chamber is formed in a hollow portion, and the annular clean air chamber is defined between the cleaner element and the air cleaner case surrounding the outer periphery thereof, and one side of the clean air chamber is formed. The discharge end of the blow-by gas recirculation passage and the intake passage leading to the intake passage of the carburetor are opened, and the secondary air passage is opened on the other side of the clean air chamber across the cleaner element. An air cleaner for an internal combustion engine, characterized in that an air intake passage has an open suction end.