JPS6345535Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a device for supplying secondary air for exhaust gas purification to the exhaust system of an internal combustion engine by using the pulsation of exhaust gas. be.

[Conventional technology and its problems]

It is well known that secondary air for purifying exhaust gas is sucked and supplied using exhaust gas pulsation, but this type of secondary air supply device uses exhaust gas pulsation to It generates a considerable amount of noise.

Therefore, as a prior art document,
Publication No. 179313 discloses that one end of a secondary air supply passage with a check valve is connected to an exhaust system, and the other end thereof is connected to a dust side chamber in an air cleaner, and the opening of this secondary air supply passage into the dust side chamber is Nearby,
It is proposed to connect the blow-by gas extraction passage from the cylinder head cover inner chamber.

In this type, the inner chamber of the cylinder head cover communicates with the secondary air supply passage via the blow-by gas extraction passage.In other words, the inner chamber of the cylinder head cover becomes a closed resonance chamber. On the other hand, the blow-by gas extraction passage becomes a throttle passage that connects the secondary air supply passage as a noise source passage and the resonance chamber, and these constitute a Helmholtz type muffler, so the secondary air supply passage It has the advantage of being able to reliably muffle noise.

However, on the other hand, in this prior art, the other end of the secondary air supply passage is opened into the dust side chamber of the air cleaner, and atmospheric air is directly sucked into the secondary air supply passage. Therefore, a filter element is required in this secondary air supply passage to remove dust and the like from the atmosphere.

On the other hand, due to the pulsation of exhaust gas, the supply of secondary air decreases in inverse proportion to the rotational speed of the internal combustion engine.
Since the amount of blowby gas generated increases in proportion to the rotational speed of the internal combustion engine, in the prior art, in the low rotational speed range such as idling of the internal combustion engine, the entire amount of blowby gas is supplied to the secondary air supply. When inhaled into the passage, the oil content in the blow-by gas adheres to the filter element in the secondary air supply passage, causing problems such as clogging the filter element and reducing its durability. In addition, in the high rotation range, part of the blow-by gas passes through the filter element in the air cleaner and flows into the intake system, so the oil in the blow-by gas adheres to the filter element in the air cleaner and becomes clogged. Problems such as decreased durability occurred.

The present invention aims to solve the problems of the prior art and to reduce the amount of lubricating oil that is lost to the exhaust system through the secondary air supply passage along with the blow-by gas.

[Means for solving problems]

To achieve this objective, the present invention connects an air cleaner installed at a higher level than the cylinder head cover to the intake manifold in the intake system to the internal combustion engine, while also connecting the air cleaner to the exhaust system from the internal combustion engine. In an internal combustion engine, the blow-by gas extraction passage from the cylinder head cover inner chamber is connected to one end of the secondary air supply passage equipped with a check valve that opens only in the direction of the air cleaner. After once rising and extending, it communicates with the clean side chamber of the air cleaner, while the other end of the secondary air supply passage is connected to the blowby gas extraction passage at a higher portion of the rising part of the blowby gas extraction passage. I configured it to do this.

[Effect]

With this configuration, the cylinder head cover interior and the blow-by gas extraction passage form a Helmholtz-type muffling device for the secondary air supply passage, similar to the prior art, so noise in the secondary air supply passage can be reliably suppressed. The sound can be muted.

As described above, the blow-by gas extraction passage from the inner chamber of the cylinder head cover is connected to the clean side chamber of the air cleaner, and the secondary air supply passage is connected in the middle of this blow-by gas extraction passage. In low rotation ranges such as idling, where the intake amount of secondary air due to exhaust gas pulsation is large and the amount of blow-by gas generated is small, the secondary air supply passage is filled with blow-by gas from the blow-by gas extraction passage and clean air from the air cleaner. Both clean air and clean air in the side chamber are inhaled. In high rotation ranges where the amount of secondary air intake is small and the amount of blowby gas generated is large, some of the blowby gas from the blowby gas extraction passage is sucked into the secondary air supply passage, and the remaining blowby gas is , introduced into the clean side chamber of the air cleaner.

In other words, the secondary air supply passage contains clean air in the clean side chamber of the air cleaner,
Since the blow-by gas is inhaled and the atmospheric air is not inhaled as it is as in the prior art, a filter element is not required in the secondary air supply passage. Since the gas is introduced into the clean side chamber of the air cleaner, the blow-by gas communicates with the filter element in the air cleaner, and as a result, the oil content in the blow-by gas
This makes it possible to avoid adhesion to the filter element.

Further, the blow-by gas extraction passage from the cylinder head cover inner chamber is once raised up to a portion higher than the air cleaner and then communicated with the inside of the air cleaner, while the other end of the secondary air supply passage is connected to the blow-by gas extraction passage. On the other hand, by connecting at a higher part of the rising part of the blowby gas extraction passage, when the blowby gas flows inside the rising part of the blowby gas extraction passage, the oil in the blowby gas is separated from the blowby gas in the rising part. Since the oil flows down along the wall surface, it is possible to reduce the amount of oil that is sucked into the secondary air supply passage together with the blow-by gas.

[Effect of idea]

Therefore, according to the present invention, the filter element in the secondary air supply passage to the exhaust system can be omitted, and the noise in the secondary air supply passage can be reduced by using the Helmholtz-type cylinder head cover chamber and the blow-by gas extraction passage. In the case of muffling the noise with a muffling device, it is possible to prevent the filter element in the air cleaner from being contaminated by oil and to reduce its durability, and it is also possible to reliably reduce the amount of lubricating oil consumed.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In the drawings, reference numeral 1 indicates a cylinder block, reference numeral 2 indicates a cylinder head, and reference numeral 3 indicates a cylinder head cover that covers the upper surface of the cylinder head 2 to form a cylinder head cover inner chamber 4. An intake manifold 7 is attached to one side of the cylinder head 2, and an air cleaner 5 located at a higher level than the cylinder head cover 3 is installed upstream of the carburetor 6 attached to the intake manifold 7.
is connected. Further, the cylinder head 2
Exhaust manifolds 9 each equipped with a catalytic exhaust gas purification device 8 are attached to the other side, and camshafts 10 and rockers for intake valves and exhaust valves (not shown) are installed in the cylinder head cover chamber 4. A valve mechanism consisting of movable arms 11, 12, etc. is provided, and the cylinder head cover inner chamber 4 is connected to the cylinder block 1 through oil drop holes 13, 14 formed in the cylinder block 1 and the cylinder head 2. Crankcase at the bottom (not shown)
is connected to.

The cylinder head cover 3 forming the cylinder head cover inner chamber 4 is provided with an oil separator 15 in the cylinder head cover chamber 4, and a zigzag passage is formed inside the oil separator 15, and one of the blow-by gases is connected to the oil separator 15. The inlet chamber 16 is communicated with the cylinder head cover inner chamber 4, and the other blow-by gas outlet chamber 17 is communicated with the clean side chamber 20 inside the filter element 19 of the air cleaner 5 via the blow-by gas extraction passage 18. In this case, the blow-by gas extraction passage 18 is configured to once rise and extend to a portion higher than the air cleaner 5 and then communicate with the clean side chamber 20 of the air cleaner 5.

In the secondary air supply passage 21 whose one end is connected to the exhaust manifold 9, a check valve 22 is provided which opens only in the direction toward the exhaust manifold 9.
The other end of the secondary air supply passage 21 is connected to the blow-by gas extraction passage 18 at a higher portion of the rising portion of the blow-by gas extraction passage 18.

In this configuration, in a low rotation range such as when idling, the amount of secondary air sucked due to the pulsation of exhaust gas is large and the amount of blow-by gas generated is small. Both the blow-by gas from the air cleaner 5 and the clean air in the clean side chamber 20 of the air cleaner 5 are taken in. In addition, in the high rotation range, the amount of secondary air intake is small and the amount of blowby gas generated is large, so some of the blowby gas from the blowby gas extraction passage 18 is transferred to the secondary air supply passage 21. The remaining blowby gas is introduced into the clean side chamber 20 of the air cleaner 5.

When the blow-by gas flows within the rising portion of the blow-by gas extraction passage 18,
Since the oil content in the blow-by gas is separated from the blow-by gas in the rising portion and flows down along the wall surface, it is possible to reduce the oil content that is sucked into the secondary air supply passage 21 together with the blow-by gas. It is.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of the main parts of the engine, and FIG. 2 is a partially cutaway plan view of FIG. 1. 1... Cylinder block, 2... Cylinder head, 3... Cylinder head cover, 4... Cylinder head cover interior, 5... Air cleaner, 9...
...Exhaust manifold, 15...Oil separator, 18...Blow-by gas extraction passage, 20...
Air cleaner clean side chamber, 21...Secondary air supply passage, 22...Check valve.

Claims (1)

[Scope of utility model registration request] An air cleaner placed higher than the cylinder head cover is connected to the intake manifold in the intake system to the internal combustion engine, while a check is installed in the exhaust system from the internal combustion engine so that it opens only in the direction toward the exhaust system. In an internal combustion engine in which one end of a secondary air supply passage provided with a valve is connected, the blow-by gas extraction passage from the inner chamber of the cylinder head cover is once raised and extended to a portion higher than the air cleaner, and then the blow-by gas extraction passage is connected to the clean side of the air cleaner. A secondary air supply passage for an internal combustion engine, characterized in that the other end of the secondary air supply passage is connected to the blowby gas extraction passage at a higher portion of a rising part of the blowby gas extraction passage. Next air supply device.