JP2020097910A - Blow-by gas recirculation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blow-by gas recirculation device improved to prevent the above-mentioned inconvenience caused by freezing at a low temperature from occurring as much as possible in a state in which a terminal end portion of a blow-by gas passage connected to an intake passage is in a state of being hardly frozen. In a blow-by gas recirculation device that returns blow-by gas in a crankcase to an intake passage a using a blow-by gas passage w, a blow-by gas passage w heats a recirculation passage portion k connected to the intake passage a. A possible heating mechanism 22 is provided, and the recirculation passage portion k is configured by connecting the blow-by gas passage w and the intake passage a in an oblique communication, and the heating mechanism 22 is connected to the blow-by gas passage w. It is provided at a lower side portion s of the connection portion 27 connected to the intake passage a, which is located on the downstream side in the air flow direction of the intake passage a. [Selection diagram] Fig. 5

Description

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

The blow-by gas recirculation system is a mechanism that allows blow-by gas that collects in the crankcase to flow back to the intake passages of the intake manifold and air cleaner, mix with a new air-fuel mixture, burn, and not release to the atmosphere as it is, that is, a blow-by gas recirculation device to 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 blow-by gas as much as possible before returning to the intake passage.

Therefore, conventionally, a structure 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 is easily captured inside the engine. As such an example, the one disclosed in Patent Document 1 is known.

JP, 2008-163837, A

Generally, the blow-by gas passage that returns the blow-by gas to the intake passage is formed of piping exposed to the outside of the engine, and therefore tends to be vulnerable to cold weather. In an extremely low temperature condition, the blow-by gas flowing back to the intake passage is cooled by the fresh air in the intake passage, and the water in the blow-by gas is frozen at the outlet of the pipe, which may cause clogging.

An object of the present invention is to provide a blow-by gas recirculation apparatus which is improved by a structure so that the end portion connected to the intake passage in the blow-by gas passage is hardly frozen and the above-mentioned inconvenience caused by freezing at low temperature is not caused as much as possible. It is in the point of providing.

The present invention provides 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,
The blow-by gas passage is equipped with a heating mechanism capable of heating a reflux passage portion connected to the intake passage,
The recirculation passage section is configured by connecting the blow-by gas passage and the intake passage in an obliquely communicated manner,
The heating mechanism is provided at a lower side portion located downstream of the connection of the blow-by gas passage and the intake passage in the air flow direction of the intake passage.

For example, the included 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 pipe passage for passing cooling water to the lower side portion. ing.
The pipe line 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 is provided on the lower side of the pipe and a cooling water outlet is provided on the upper side. The intake passage is a primary side air passage that sends air to the supercharger.

According to the present invention, since the blow-by gas passage and the intake passage are obliquely connected to each other, 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 easy to concentrate on the lower-side portion on the downstream side in the air flow direction of the connection points. Since the heating mechanism warms and heats the lower side portion where the flow is likely to be concentrated, the heat by the heating mechanism can be efficiently conducted to the blow-by gas that joins the reflux passage portion and the intake passage.

Therefore, just by heating the lower side part of the return passage part, the water in the blow-by gas that has been recirculated to the intake passage during freezing is cooled by the low temperature fresh air and freezes, or due to the freezing. It is possible to prevent the inner passage in the return passage portion from being narrowed or blocked.

As a result, by devising 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 be frozen, 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 that does not occur as much as possible.

Front view of industrial diesel engine Top view of industrial diesel engine Left side view of an industrial diesel engine Perspective view of the upper part of the industrial diesel engine seen from the upper left front Perspective view of essential parts showing heating mechanism A heating mechanism is shown, (A) is a plan view of a main part, (B) is a sectional view taken along line ZZ of (A). The reflux passage part is shown, (A) is a partially cutaway right side view, (B) is a horizontal sectional view

Hereinafter, an embodiment of a blow-by gas recirculation system 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 referred to as an engine) E, a cylinder head 2 is attached to an upper portion of a cylinder block 1, and a head cover 3 is attached to an upper portion of the cylinder head 2. Assembled, the oil pan 4 is attached to the lower portion of the cylinder block 1.
A transmission case 5 is assembled to 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 belt 8 mounted on a shaft end of a crankshaft (not shown), a drive fan pulley 6A of the engine cooling fan 6, and a passive pulley 9A of a dynamo (alternator) 9, It is equipped with a water flange 30 and the like. An exhaust manifold 11, a supercharger 12, a starter 13, an EGR cooler 14 and the like are provided on the left side of the engine E. An intake manifold 15, an oil filter 17, etc. are provided on the right side of the engine E. A compressor downstream suction passage (secondary air passage) 18 (see FIG. 2) is arranged above the engine E.

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

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

As shown in FIGS. 2, 3 and 5, the compressor upstream suction passage 20 has a connecting pipe 29 externally fitted to the inlet pipe 12a of the compressor housing 12A and a direct connecting pipe 29 internally fitted to the connecting pipe 29. The pipe 23 is provided with an air passage pipe (not shown) that connects the straight pipe 23 and an air cleaner (not shown). As will be described later in detail, the straight pipe 23 is integrally provided with a rush pipe (end 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 a blow-by gas passage w) that connects the upper left side of the head cover 3 and the compressor upstream suction passage 20. 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 recirculation passage portion k in which the blow-by gas passage w is connected to the intake passage a is provided. The recirculation passage portion k is configured by connecting the end portion of the blow-by gas passage w, that is, the rush pipe 28 and the straight pipe 23 (intake passage a) in an oblique communication. The heating mechanism 22 is provided in a lower side portion s of the connection portion 27 between the blow-by gas passage w and the intake passage a, which is located downstream in the air flow direction (white arrow e) of the straight pipe 23. ..

The heating mechanism 22 and the reflux passage portion k will be described. As shown in FIGS. 5 to 7, the straight pipe 23 made of a metal round pipe having the axis P and the rush pipe 28 made of the metal round pipe having the axis Q are sandwiched between the axes P and Q. The plunge pipe 28 is attached to the straight pipe 23 obliquely so that the angle θ becomes an obtuse angle (for example, 125 degrees).
In the present embodiment, the return passage portion k is substantially composed of the straight pipe 23 and the rush pipe 28, and in a narrow sense, is the portion where the straight pipe 23 and the rush 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 plunge pipe 28 intersect in a broad sense, and in a narrow sense, the outer peripheral surfaces of the straight pipe 23 and the plunge pipe 28 are mutually. Refers to the elliptical surrounding area where
As shown in FIGS. 1 and 5, the straight pipe 23 is arranged in a posture in which it is twisted around the axis P so that the rush pipe 28 faces obliquely upward to the right. The twist angle β is set to, for example, about 40 degrees, but other angles may be set. Therefore, the pipe line 24 is also not vertically oriented vertically, but is arranged in an obliquely vertical posture so as to face to the lower right and upper left.

The heating mechanism 22 is configured by attaching a pipe line 24 through which the cooling water r passes to the lower side portion s, and a cooling water inlet part 25 made of a metal pipe is provided below the pipe line 24 made of a metal pipe. Moreover, cooling water outlets 26 made of metal pipes are provided on the upper side in a liquid-tight manner. The pipe line 24 is welded (welded) in a posture in which its axis (not shown) is oriented in a direction orthogonal to both the axis P of the straight tube 23 and the axis Q of the thrust tube 28. It is mounted in a state of being in contact with both 23 and the rush pipe 28. The cooling water inlet portion 25 has its inlet side end portion bent in a direction perpendicular to the axis P of the straight pipe 23, and the cooling water outlet portion 26 has its outlet side end portion of the straight pipe 23. It is bent in the direction along.

As shown in FIGS. 6 and 7, the straight pipe 23 and the rush pipe 28 forming the heating mechanism 22 are formed in one metal part, and the pipe line 24 is exposed in the intake passage a and the blow-by gas passage w. The pipe line 24 may be fixed in a liquid-tight manner by shaving and welding so that the pipe and the blow-by gas come into direct contact with each other. The thermal conductivity can be further improved as compared with a means in which the rush pipe 28 is welded to the straight pipe 23, and the pipe lines 24 are welded to and integrated with the outer peripheral surfaces of the pipes 24 in contact with each other. Further, a structure in which the straight pipe 23, the rush pipe 28, and the conduit 24 are made into one component is also possible by casting or forging.

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

Although the air in the straight pipe 23 flows in the direction along the axis P (white arrow in FIG. 5), the blow-by gas in the rush pipe 28 flows in the direction along the axis Q (solid arrow in FIG. 5). Since the straight pipe 23 and the rush pipe 28 intersect obliquely, the blow-by gas tends to be concentrated in the lower side portion s due to the influence of the air flow near the end of the rush pipe 28. Therefore, since the pipe 24 is provided at the lower side where the flow is easily concentrated, 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 k and the intake passage a. Can be made

In extremely cold weather, the water in the blow-by gas that has been recirculated to the rush pipe 28 or the straight pipe 23 is cooled by the low-temperature fresh air and freezes, and the freezing narrows or blocks the internal passage of the rush pipe 28. The advantage that the inconvenience that occurs does not occur is obtained. Since the straight pipe 23, the rush pipe 28, and the pipe line 24 are made of metal pipes such as structural steel plates, aluminum alloys, and stainless steel, the reflux passage portion k has excellent thermal conductivity, and the cooling water r It is possible to efficiently or quickly heat the blow-by gas g and cold fresh air (for example, air at -20 to -30 degrees) by the heat of.

Since the rush pipe 28 is joined to the straight pipe 23 in an obliquely intersecting state in which the included angle θ is an obtuse angle, the warming point by the pipe line 24 is made as small as possible (narrow) point (lower side point s), but reflux is also performed. The heating mechanism 22 is configured to efficiently heat the passage portion k and effectively prevent freezing by reducing the ice generation area. Since the cooling water r is put into the pipe line 24 from the bottom and discharged from the top, the reflux passage part k can be effectively warmed as compared with the opposite configuration.

[Another embodiment]
(1) The conduit 24 may be a pipe bent in an arc shape or an elliptic 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 increased and the heating efficiency can be improved.
(2) The reflux passage portion k may be configured such that the included angle θ formed by the straight pipe 23 and the rush pipe 28 at the lower side portion s is an acute angle.

(3) The pipeline 24 may be added to the connection point 27 on the side opposite to the lower side location s, or may be added to a location other than 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 rush pipe 28 to the straight pipe 23 is different from 125 degrees, such as 140 degrees or 115 degrees, depending on the engine model, the difference in the weather environment of the place of use, and other factors. Can be changed and set.
(6) It is also possible to configure the pipe line 24 to be an arcuate pipe along the outer peripheral surface of the straight pipe 23 or an arcuate pipe along the outer peripheral surface of the plunge pipe 28.
(7) The twist angle (tilt angle) β around the axis P of the straight pipe 23 may be an angle other than about 40 degrees.

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

Claims (7)

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,
The blow-by gas passage is equipped with a heating mechanism capable of heating a reflux passage portion connected to the intake passage,
The recirculation passage section is configured by connecting the blow-by gas passage and the intake passage in an obliquely communicated manner,
A blow-by gas recirculation device, wherein 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 blow-by gas recirculation device according to claim 1, wherein an angle formed by the blow-by gas passage and the intake passage at the lower side 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 pipe passage for passing cooling water to the lower side portion. The blow-by gas recirculation device according to claim 3, wherein the pipe line is attached in a state of straddling both the blow-by gas passage and the intake passage at the lower side portion. The blow-by gas recirculation apparatus according to claim 3, wherein the conduit 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 a lower side of the pipe and a cooling water outlet portion is provided on an upper side thereof. 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 that sends air to the supercharger.

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