JP7092652B2 - Blow-by gas recirculation device - Google Patents

Description

The present invention relates to a blow-by gas recirculation device installed in an industrial engine, an engine for a traveling vehicle, or the like.

A mechanism that recirculates the blow-by gas that collects in the crankcase to the intake passages such as the intake manifold and air cleaner, mixes it with a new air-fuel mixture and burns it, and prevents it from being released to the atmosphere as it is, that is, a blow-by gas recirculation device is installed in the engine. It is provided. In an engine with a blow-by gas recirculation device, it is desirable to remove liquid components such as oil (oil mist) and water contained in the blow-by gas as much as possible before returning the engine to the intake passage.

Therefore, conventionally, a configuration is often adopted in which the liquid component is returned from the crankcase to the intake passage through the cylinder head and the head cover so that the liquid component can be easily captured inside the engine. As such an example, the one disclosed in Patent Document 1 is known.

Japanese Unexamined Patent Publication No. 2008-1633837

Generally, the blow-by gas passage that returns the blow-by gas to the intake passage is composed of pipes exposed to the outside of the engine, and therefore tends to be vulnerable to cold. In the extremely low temperature condition, the blow-by gas returning to the intake passage is cooled by the fresh air in the intake passage, and the moisture in the blow-by gas freezes at the outlet of the pipe, which may cause clogging.

An object of the present invention is to provide a blow-by gas recirculation device which is improved so that the above-mentioned inconvenience due to freezing at a low temperature is not caused as much as possible by making it difficult to freeze at the terminal portion connected to the intake passage in the blow-by gas passage by devising a structure. It is in the point of providing.

The present invention relates to a blow-by gas recirculation device configured to return blow-by gas in a crankcase to an intake passage using a blow-by gas passage.
A heating mechanism capable of heating the reflux passage portion in which the blow-by gas passage is communicated with the intake passage is provided.
The return passage portion is configured by connecting the blow-by gas passage and the intake passage in an oblique manner.
The heating mechanism is provided at a lower side portion of the connection portion between the blow-by gas passage and the intake passage, which is located on the downstream side in the air flow direction of the intake passage .
The heating mechanism is configured by attaching a pipeline through which cooling water, engine oil, or exhaust gas passes to the lower side.
The pipeline is set to have a diameter larger than the diameter of the inlet portion made of a pipe liquidtightly provided at one end of the pipeline and the diameter of the outlet portion made of a pipe liquidtightly provided at the other end of the pipeline. It is characterized by being.

For example, the sandwiching angle between the blow-by gas passage and the intake passage at the lower side portion is set to an obtuse angle, and the heating mechanism is configured by attaching a pipeline through which cooling water passes to the lower side portion. ing.
The pipeline is attached by welding in a state of straddling both the blow-by gas passage and the intake passage at the lower side portion.
A cooling water inlet portion is provided on the lower side of the pipeline, and a cooling water outlet portion is provided on the upper side. Further, the intake passage is a primary side air passage that sends air to the turbocharger.

According to the present invention, since the blow-by gas passage and the intake passage are connected in an oblique manner, the blow-by gas flowing from the blow-by gas passage to the return passage portion is affected by the air flow in the intake passage. , It becomes easier to concentrate on the lower side of the downstream side in the air flow direction of the connection points. Since the heating mechanism warms and heats the lower portion where the flow tends to concentrate, the heat generated by the heating mechanism can be efficiently conducted to the blow-by gas joining the reflux passage and the intake passage.

Therefore, by simply heating the lower part of the reflux passage, the water in the blow-by gas that has been refluxed to the intake passage is cooled by the low-temperature fresh air and frozen in extremely cold weather, and due to the freezing. The internal passage in the return passage portion is prevented from being narrowed or clogged.

As a result, by devising a method such as connecting the blow-by gas passage and the intake passage in an oblique manner, the end portion of the blow-by gas passage connected to the intake passage is made difficult to freeze, and the above-mentioned inconvenience due to freezing at low temperature is caused. It is possible to provide an improved blow-by gas recirculation device so as not to occur as much as possible.

Front view of industrial diesel engine Floor plan of industrial diesel engine Left side view of industrial diesel engine A perspective view of the upper part of an industrial diesel engine from the upper left front Perspective view of the main part showing the heating mechanism The heating mechanism is shown, (A) is a plan view of a main part, and (B) is a sectional view taken along line ZZ of (A). The return passage portion is shown, (A) is a right side view of a partial notch, and (B) is a cross-sectional view of a horizontal cut.

Hereinafter, embodiments of the blow-by gas recirculation device according to the present invention will be described with reference to the drawings when applied to an industrial diesel engine.

As shown in FIGS. 1 to 4, in an industrial diesel engine (hereinafter, simply abbreviated as an engine) E, a cylinder head 2 is assembled on the upper part of a cylinder block 1, and a head cover 3 is attached on the upper part of the cylinder head 2. It is assembled, and the oil pan 4 is assembled at the lower part of the cylinder block 1.
A transmission case 5 is assembled at the front end of the cylinder block 1, an engine cooling fan 6 is arranged at the front of the transmission case 5, and a flywheel housing 7 is arranged at the rear of the cylinder block 1. The upper half of the cylinder block 1 is formed in the cylinder 1A, and the lower half is formed in the crankcase 1B.

At the front of the engine E, a drive pulley 8 attached to the shaft end of a crank shaft (not shown), a drive fan pulley 6A for the engine cooling fan 6, and a transmission belt 10 straddling the passive pulley 9A of the dynamo (alternator) 9. It is equipped with a water flange 30 and the like. The left side of the engine E is equipped with an exhaust manifold 11, a supercharger 12, a starter 13, an EGR cooler 14, and the like. The right side of the engine E is equipped with an intake manifold 15, an oil filter 17, and the like. Above the engine E, a suction passage (secondary air passage) 18 (see FIG. 2) on the downstream side of the compressor is arranged.

An exhaust gas treatment device 19 is provided at the upper portion and the rear portion of the engine E. The exhaust gas treatment device 19 includes a primary exhaust gas treatment device (DPF or the like) 19A arranged at the rear of the engine E on the upper part of the flywheel housing 7, and a secondary exhaust gas treatment device 19 arranged on the upper part of the engine E near the rear of the head cover 3. It has an apparatus (SCR, DOC, etc.) 19B. These exhaust gas treatment devices 19 are supported by a mounting frame 16 bolted to the cylinder block 1.

The intake passage a is a general term having a compressor upstream side suction passage 20, the above-mentioned compressor downstream side suction passage 18, and an intake manifold 15. The intake passage 20 on the upstream side of the compressor is an intake passage a formed by a pipe connecting the air cleaner (not shown) and the compressor housing 12A of the supercharger (turbocharger) 12. The intake passage 18 on the downstream side of the compressor is an intake passage a formed by a pipe connecting the compressor housing 12A and the intake manifold 15.

As shown in FIGS. It is provided with a pipe 23 and an air passage pipe (not shown) connecting the straight pipe 23 and an air cleaner (not shown). As will be described in detail later, the straight pipe 23 is integrally provided with a plunge pipe (terminal portion of the blow-by gas passage w) 28 and a heating mechanism 22.

The engine E is equipped with a blow-by gas recirculation device A (see FIGS. 2, 3 and 4) that returns the blow-by gas in the crankcase 1B to the intake passage a using the blow-by gas passage w including the inside of the head cover 3. There is. The blow-by gas recirculation device A has a gas duct 21 (an example of the blow-by gas passage w) connecting the upper left side of the head cover 3 and the suction passage 20 on the upstream side of the compressor. As shown in FIGS. 2 to 4, the gas duct 21 includes a duct main pipe 21A connected to the head cover 3 and a curved pipe 21B connecting the duct main pipe 21A and the inrush pipe 28. ing.

As shown in FIGS. 2, 4, and 5, a heating mechanism 22 capable of heating the reflux passage portion k in which the blow-by gas passage w is communicated with the intake passage a is provided. The return passage portion k is configured by connecting the terminal portion of the blow-by gas passage w, that is, the inrush pipe 28 and the straight pipe 23 (intake passage a) in an oblique manner. The heating mechanism 22 is provided at a lower side portion s located on the downstream side in the air flow direction (white arrow e) of the straight pipe 23 of the connection portions 27 between the blow-by gas passage w and the intake passage a. ..

The heating mechanism 22 and the reflux passage portion k will be described. As shown in FIGS. 5 to 7, a straight pipe 23 made of a metal round pipe having an axis P and an intrusion pipe 28 made of a metal round pipe having an axis Q are sandwiched between the axis P and Q. The plunge pipe 28 is attached at an angle to the straight pipe 23 so that the angle θ is an obtuse angle (eg, 125 degrees).
In the present embodiment, the return passage portion k is substantially composed of a straight pipe 23 and a plunge pipe 28, and in a narrow sense, is a portion where the straight pipe 23 and the plunge pipe 28 intersect.

The connection point 27 between the blow-by gas passage w and the intake passage a is a portion where the straight pipe 23 and the inrush pipe 28 intersect in a broad sense, and in a narrow sense, the outer peripheral surfaces of the straight pipe 23 and the inrush pipe 28. Refers to the elliptical peripheral part where
As shown in FIGS. 1 and 5, the straight pipe 23 is arranged in a twisted posture around the axis P so that the plunge pipe 28 faces diagonally upward to the right. The twist angle β is set to, for example, around 40 degrees, but other angles may be used. Therefore, the pipeline 24 is also arranged in an oblique vertical posture so as to face the lower right and upper left, not in the vertical vertical direction.

The heating mechanism 22 is configured by attaching a pipeline 24 through which the cooling water r passes to a lower side portion s, and a cooling water inlet portion 25 made of a metal pipe is provided below the pipeline 24 made of a metal pipe. Moreover, the cooling water outlet portion 26 made of a metal pipe is provided on the upper side in a liquid-tight manner. The pipeline 24 is a straight pipe by welding (welding, etc.) in a posture in which the axis (not shown) faces in a direction orthogonal to both the axis P of the straight pipe 23 and the axis Q of the inrush pipe 28. It is attached so as to be in contact with both the 23 and the plunge pipe 28. The inlet side end of the cooling water inlet portion 25 is bent in a direction orthogonal to the axial center P of the straight pipe 23, and the cooling water outlet portion 26 has the outlet side end portion of the straight pipe 23 axial center P. It is bent in the direction along.

As shown in FIGS. 6 and 7, the straight pipe 23 and the inrush pipe 28 constituting the heating mechanism 22 are formed as one metal component, and the pipe line 24 is exposed to the intake passage a and the blow-by gas passage w. The pipeline 24 may be liquid-tightly fixed by shaving and welding so that it comes into direct contact with air or blow-by gas. It is possible to further improve the thermal conductivity as compared with the means of welding the plunge pipe 28 to the straight pipe 23 and welding and integrating the pipe line 24 in a state where the pipe line 24 is in contact with the outer peripheral surface of each. Further, it is possible to have a structure in which the straight pipe 23, the plunge pipe 28, and the pipe line 24 are made of one part by casting or forging.

As shown in FIGS. 3 and 4, the first connecting tube 34 connecting the branch pipe (not marked) from the EGR cooler cooling water pipe 32 and the cooling water inlet portion 25, the water pump 31 and the cooling water outlet portion. A second connecting tube 33 that connects the 26 to the 26 is provided. Therefore, the cooling water r enters the pipeline 24 from the lower cooling water inlet portion 25, is thermally conducted to the reflux passage portion k when passing through the pipeline 24, and then exits from the upper cooling water outlet portion 26. Go.

The air in the straight pipe 23 flows in the direction along the axis P (white arrow in FIG. 5), and the blow-by gas in the inrush pipe 28 flows in the direction along the axis Q (solid arrow in FIG. 5). Since the straight pipe 23 and the plunge pipe 28 intersect at an angle, the blow-by gas tends to be affected by the air flow near the end of the plunge pipe 28 and concentrate on the portion s on the lower side. Therefore, since the pipeline 24 is provided on the lower side where the flow tends to concentrate, the heat of the cooling water r is efficiently conducted to the blow-by gas (blow-by gas passage w) that joins the reflux passage portion k and the intake passage a. Can be made to.

In extremely cold weather, the water in the blow-by gas that has been returned to the inrush pipe 28 and the straight pipe 23 is cooled by low-temperature fresh air and freezes, and the freezing causes the internal passage of the inrush pipe 28 to narrow or become clogged. There is an advantage that the inconvenience does not occur. Since the straight pipe 23, the plunge pipe 28, and the pipe line 24 are made of a metal pipe such as a structural steel plate, an aluminum alloy, or stainless steel, the return passage portion k has excellent thermal conductivity, and the cooling water r Blow-by-gas g and cold fresh air (eg, air at -20 to -30 degrees) can be heated efficiently or quickly by the heat of.

Since the inrush pipe 28 is joined to the straight pipe 23 in an obtuse angle with an obtuse angle θ, the warming place by the pipe line 24 is made as small (narrow) as possible (lower side place s), but is refluxed. A heating mechanism 22 that can efficiently heat the passage portion k and effectively prevent freezing by reducing the ice generation area is configured. Since the cooling water r is put into the pipeline 24 from below and discharged from above, the reflux passage portion k can be effectively warmed as compared with the opposite configuration.

[Another Embodiment]
(1) The pipeline 24 may be formed of a pipe bent in an arc shape or an elliptical arc shape along the connection point 27. There is an advantage that the passage length of the cooling water r in the return passage portion k can be lengthened and the heating efficiency can be improved.
(2) The reflux passage portion k having a structure in which the sandwiching angle θ formed by the straight pipe 23 and the plunge pipe 28 at the lower side portion s is an acute angle may be used.

(3) The pipeline 24 may be added to the opposite side of the lower side portion s of the connection portion 27, or the pipeline 24 may be added to a location other than the location on the opposite side.
(4) As the heat source of the heating mechanism 22, in addition to the cooling water r, a fluid such as engine oil or exhaust gas can be used.

(5) The oblique angle of the inrush pipe 28 to the straight pipe 23 varies from 125 degrees depending on the engine model, the difference in the weather environment of the place of use, and other factors such as 140 degrees and 115 degrees. Can be changed and set.
(6) It is also possible to form the pipeline 24 as an arc-shaped pipe along the outer peripheral surface of the straight pipe 23 or an arc-shaped pipe along the outer peripheral surface of the inrush pipe 28.
(7) The twist angle (tilt angle) β around the axis P of the straight pipe 23 may be an angle other than around 40 degrees.

1B Crank case 12 Supercharger 20 Primary side air passage 22 Heating mechanism 24 Pipeline 25 Cooling water inlet part 26 Cooling water outlet part 27 Connection point a Intake passage k Reflux passage part r Cooling water s Lower side part w Blow-by gas passage θ angle

Claims (7)

A blow-by gas recirculation device configured to return the blow-by gas in the crankcase to the intake passage using the blow-by gas passage.
A heating mechanism capable of heating the reflux passage portion in which the blow-by gas passage is communicated with the intake passage is provided.
The return passage portion is configured by connecting the blow-by gas passage and the intake passage in an oblique manner.
The heating mechanism is provided at a lower side portion of the connection portion between the blow-by gas passage and the intake passage, which is located on the downstream side in the air flow direction of the intake passage .
The heating mechanism is configured by attaching a pipeline through which cooling water, engine oil, or exhaust gas passes to the lower side.
The pipeline is set to have a diameter larger than the diameter of the inlet portion made of a pipe liquidtightly provided at one end of the pipeline and the diameter of the outlet portion made of a pipe liquidtightly provided at the other end of the pipeline. Blow- by gas recirculation device.

The blow-by gas recirculation device according to claim 1, wherein the sandwiching angle between the blow-by gas passage and the intake passage at the lower portion is set to an obtuse angle. The blow-by gas recirculation device according to claim 1 or 2, wherein the heating mechanism is configured by attaching a pipeline through which cooling water passes to the lower side portion. The blow-by gas recirculation device according to claim 3, wherein the pipeline is installed so as to straddle both the blow-by gas passage and the intake passage at the lower side portion. The blow-by gas recirculation device according to claim 3 or 4, wherein the pipeline is attached to the lower side portion by welding. The blow-by gas recirculation device according to any one of claims 3 to 5, wherein a cooling water inlet portion is provided on the lower side of the pipeline and a cooling water outlet portion is provided on the upper side. The blow-by gas recirculation device according to any one of claims 1 to 6, wherein the intake passage is a primary side air passage for sending air to the turbocharger.

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