JP2020112101A - Engine with blow-by gas recirculation device - Google Patents

Abstract

To provide an engine with a blow-by gas recirculation device which is improved not to cause inconveniences to the utmost due to freezing at a low temperature by devising its construction into the state of being hardly frozen in a blow-by gas passage at its terminal end connected to an intake system.SOLUTION: The engine with the blow-by gas recirculation device is constructed to return blow-by gas from a crankcase 1B through the internal of a head cover 3 to an intake passage k. The intake passage k has a cover intake passage 19A provided in the head cover 3, and a blow-by gas passage 26 of the head cover 3 is communicated with the cover intake passage 19A. The blow-by gas passage 26 and the cover intake passage 19A are communicated via a labyrinth-shaped communication passage 40.SELECTED DRAWING: Figure 6

Description

The present invention relates to an engine with a blow-by gas recirculation device, such as an industrial engine or a traveling vehicle engine.

The engine is equipped with a blow-by gas recirculation device that recirculates the blow-by gas that collects in the crankcase to the intake passage such as the intake manifold, mixes it with a new mixture, and burns it so that it does not release to the atmosphere. Has been. 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

In general, the pipe that returns blow-by gas to the intake system is 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 connect a blow-by gas in a crankcase to an intake passage through the inside of a head cover, and then connect the blow-by gas to an intake passage in the blow-by gas passage by a structural modification. It is an object to provide an engine with a blow-by gas recirculation device which is improved to prevent the above-mentioned inconvenience due to freezing at a low temperature from occurring as much as possible in a state where it is difficult to be frozen at the end portion.

The present invention, in an engine with a blow-by gas recirculation device,
Blow-by gas in the crankcase is configured to return to the intake passage after passing through the inside of the head cover,
The intake passage has a cover intake passage provided in the head cover, and the blow-by gas passage of the head cover and the cover intake passage are communicated with each other.
The blow-by gas passage and the cover intake passage are connected by a labyrinth-like communication passage.

For example, the cover intake passage may be formed in a gas outlet cover detachably attached to the head cover. It is more preferable that the communication passage is composed of a gasket provided between the gas outlet cover and the head cover and the gas outlet cover.

It is convenient that a heat insulating portion is provided between a portion of the communication passage other than an end portion on the intake passage side and the cover intake passage, and the heat insulating portion opens to a gasket side surface of the gas outlet cover. It is more expedient when in this case it is constituted by a recess or a hole formed in the gas outlet cover. Moreover, it is more preferable that the opening of the recess or hole is covered with the gasket.

The head cover is a place where heat is conducted from the cylinder head and becomes warm, and the blow-by gas is returned to the cover intake passage that is a part of the warm head cover. Therefore, even if the intake air is cold due to extremely cold weather, the temperature of the air flowing through the cover intake passage rises, so that the water in the blow-by gas recirculated to the intake passage such as the compressor upstream intake passage is not frozen. Or it will be suppressed.

Further, since the communication path between the blow-by gas passage and the cover intake passage is labyrinth-shaped, the oil component in the blow-by gas is difficult to be drawn into the labyrinth-like communication path, and even if it is drawn in, it is shaken off during the passage due to the labyrinth shape. Like Therefore, the effect of removing the oil from the blow-by gas is exerted in the communication passage.

As a result, while strengthening the action of removing the oil component from the blow-by gas, the end portion of the blow-by gas passage on the side of the intake passage is made difficult to freeze, and the above inconvenience due to freezing at low temperatures has been improved as much as possible. An engine with a blow-by gas recirculation device can be provided.

Left side view of an industrial diesel engine Front view of the engine shown in FIG. Right side view of the engine shown in FIG. Plan view of the engine shown in FIG. Rear view of the engine shown in FIG. Plan view around the front of the head cover Left side view of partially cutout showing the head cover and cover intake passage Top view of head cover Bottom view of head cover The front view which shows the head cover and gas outlet cover of the XX sectional view of FIG. A gas outlet cover is shown, (A) is a plan view, (B) is a bottom view A blow-by gas outlet part and a valve operating device are shown, (A) is a cross-sectional view and (B) is a longitudinal cross-sectional view of the main part. (A) Side view of the discharge reed valve, (B) Side view of the return reed valve (A) Plan view of the gasket, (B) Cross-sectional view of the gasket and its upper and lower parts

Hereinafter, an embodiment of an engine with a blowby 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 5, 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. The cylinder block 1 is assembled, and the oil pan 4 is assembled under the cylinder block 1. A transmission case 5 is attached 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 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 part of the engine E, a drive belt 8 which is attached to a drive pulley 8 attached to a shaft end of a crank shaft (not shown), a drive fan pulley 6A of an engine cooling fan 6, and a passive pulley 9A of a dynamo (alternator) 9, A water flange 21 and the like are provided. An exhaust manifold 11, a supercharger 12, a starter 13, an oil filter 14 and the like are provided on the left side of the engine E. An intake manifold 15, a fuel injection pump housing 16, a stop solenoid 17, etc. are provided on the right side of the engine E, and three injectors 18, a compressor upstream suction passage 19, a compressor downstream suction passage 20, etc. are arranged above the engine E. There is.

The compressor downstream suction passage 20 includes a starting end pipe 20A which is connected to the compressor housing 12A and is arranged directly above the head cover 3 and an ending end pipe 20B which connects the starting end pipe 20A and the intake manifold 15. Is configured. As shown in FIG. 4, the start end side tube 20A is arranged in a state along the rear side position of the cover intake passage 19A in a plan view. The bent pipe 19B, the start end side pipe 20A, and the end side pipe 20B may be made of pipes made of a flexible material such as rubber, or metal pipes.

As shown in FIGS. 4, 6, 7 and 10, the engine E has a blow-by gas recirculation configured to guide the blow-by gas in the crankcase 1B from the inside of the head cover 3 to the intake passage k. Equipment A is equipped. The head cover 3 is a bottomless box-shaped (upper lid-shaped) component that is mounted on the cylinder head 2 across the valve operating device B, and has a plurality of ribs 3a extending left and right formed inside the cover. An engine oil supply hole 22 is provided in the rear portion of the head cover 3.

The intake passage k has a cover intake passage 19A provided in the blow-by gas outlet portion 3A of the head cover 3, and the blow-by gas passage 26 of the blow-by gas outlet portion 3A and the cover intake passage 19A are communicated with each other. The cover intake passage 19A is configured as a part of the compressor upstream intake passage 19 that connects the air cleaner 23 (see FIGS. 4 and 6) and the supercharger 12. That is, the compressor upstream-side intake passage 19 is configured to include the cover intake passage 19A and the bent pipe 19B connecting the cover intake passage 19A and the compressor housing 12A of the supercharger 12. It should be noted that the intake passage k is a concept of all passages for sending the air a to the combustion chamber (not shown) such as the air cleaner 23 and the intake manifold 15.

Here, the main function of the blow-by gas recirculation device A (recirculation part to the intake passage k) will be briefly described. As shown in FIGS. 6 and 7, the blow-by gas g flowing from the cylinder block 1 into the internal space of the head cover 3 passes through the discharge reed valve 31 and is the space portion 26 which is the blow-by gas passage of the blow-by gas outlet portion 3A. to go into. The blow-by gas g that has entered the space 26 also called a CCV (crankcase ventilation) chamber is returned to the cover intake passage 19A, that is, the intake passage k, through the communication hole 38 of the gasket 35 and the communication passage 40 (described later). To be done.

Next, the head cover 3 and the cover intake passage 19A will be described in detail.
As shown in FIGS. 6 to 10, the head cover 3 having a rounded quadrangle (oval shape) in a plan view has a blow-by gas outlet portion 3A that is open upward and is formed at the front end portion of the top wall 3C. .. The blow-by gas outlet portion 3A is formed in the head cover 3 as a lidless box-shaped portion having a space portion 26 surrounded by the vertically facing partition side wall 24 and the bottom wall 25, and a joint surface 27 which is an upper surface.

The space 26, which is the blow-by gas passage, is a trapezoidal part having a short side on the right side in plan view, and the bottom wall 25 is different from the main bottom surface 25A having a shallow depth in the front-back direction. It has sink bottom surfaces 25B and 25B formed in front of and behind the bottom surface 25A. A discharge reed valve 31 for sending out the blow-by gas g from the inside of the head cover 3 is provided in a lateral (leftward) posture at a front-rear central portion of the main bottom surface 25A having a lateral T-shape in a plan view.

As shown in FIGS. 7 to 10, 12, and 13, the discharge reed valve 31 includes a thin discharge valve element 31A arranged on the main bottom surface 25A and a thick discharge valve guide 31B, respectively. It is configured by bolting to the bottom wall 25 at the root side of the. The rounded tip portion 31a of the discharge valve body 31A is arranged above the discharge valve hole 31C formed in the bottom wall 25 by opening to the main bottom surface 25A, and usually serves as a lid of the discharge valve hole 31C (valve closed). Status). The portion of the discharge valve hole 31C in the bottom wall 25 is formed in a protruding hole wall 25a that has a circular shape that is concentric with the discharge valve hole 31C when viewed in the vertical direction and projects downward.

The sink bottom surface 25B includes an inclined surface 32 that becomes lower as it goes from the front to the rear of the discharge reed valve 31 to the front or rear, and the lowest surface 33 continuing to the lower side of the inclined surface 32 (see FIG. 8). The lowest surface 33 is configured to be located on the left side of the inclined surface 32. A return valve hole 33a that penetrates vertically is formed in each of the lowest surfaces 33, 33 of the bottom wall 25, and a return reed valve 34 for the return valve hole 33a is provided.

As shown in FIGS. 7 to 10, 12, and 13, the return reed valve 34 includes a return valve body 34A that is in contact with a side surface of the bottom wall 25 opposite to the lowest surface 33, that is, the lowest back surface 33A, and a thick return valve 34A. The valve guide 34B and the valve guide 34B are bolted to the bottom wall 25 at the respective root sides. The return reed valve 34 is provided upside down with respect to the discharge reed valve 31, and normally, the return valve hole 33a is lightly closed by the tip portion 34a of the return valve body 34A, or the return valve body 34A is It is in a slightly opened state due to a slight sagging displacement.

Each of the return reed valves 34, 34 is arranged in a sideways posture in which the tip portion 34a is on the left side, and is a place where the oil mist captured from the blow-by gas g in the space portion 26 is returned to the internal space of the head cover 3. The diameter of each return valve hole 33a is smaller than the diameter of the discharge valve hole 31C. It is convenient that the discharge valve body 31A and the return valve body 34A, and the discharge valve guide 31B and the return valve guide 34B are the same parts.

As shown in FIGS. 6 to 8 and 11, a gas outlet cover 3B is bolted onto the blow-by gas outlet portion 3A, and the gas outlet cover 3B includes a lid cover portion 36 and a cover intake passage 19A. Is configured. The lid cover portion 36 has an outer shape similar to that of the blow-by gas outlet portion 3A in a plan view, and is a portion fixed to the head cover 3 by bolting at three locations with the gasket 35 interposed therebetween.

As shown in FIGS. 11A and 11B, in the cover intake passage 19A, the passage end portion 19b of the cover intake passage 19A is outside in the longitudinal direction of the head cover 3 with respect to the passage start end portion 19a of the cover intake passage 19A. It is formed in a meandering passage that is bent in a state of approaching. Specifically, the cover intake passage 19A extends in a direction orthogonal to the head cover longitudinal direction (front-back direction) (an example of intersection) and is parallel to each other, and includes a passage start end portion 19a and a passage end portion 19b, and an end of the passage start end portion 19a and a passage. It is formed in a meandering passage having a crank-like (substantially Z-shaped) plan view, having a passage intermediate portion 19c diagonally extending in the front, rear, left, and right directions that connects the starting end of the end portion 19b.

The passage intermediate portion 19c is formed in a groove-like passage portion having a downward U-shaped cross section, and the opening 37 at the lower end thereof has a shape similar to that of the passage intermediate portion 19c in plan view and opens downward. Has been formed. Further, the lid cover portion 36 is formed with a gas passage recess 36a located below the opening 37 and opening downward, and bolt holes 3b are formed at three locations.

As shown in FIG. 14(A), the gasket 35 is a thin plate (sheet-like) having one communication hole 38 and three bolt insertion holes 39. As shown in FIG. 14B, the gasket 35 is sandwiched between the joint surface 27 which is the upper surface of the blow-by gas outlet portion 3A and the joint lower surface 36b (of the gas outlet cover 3B) of the lid cover portion 36. It is provided in the state. The outer contour shape of the joint surface 27 of the blow-by gas outlet portion 3A, the outer contour shape of the gasket 35, and the outer contour shape of the lid cover portion 36 are the same, but not limited thereto.

As shown in FIG. 6, the space portion 26 of the blow-by gas outlet portion 3A has an upper surface opening that covers almost the entire surface of the opening 37 of the lid cover portion 36, and the communication hole 38 of the gasket 35 has a space portion. It is the only place where 26 and the opening 37 communicate with each other. That is, the communication hole 38 is a hole that determines a communication area between the passage intermediate portion 19c (opening 37) and the space portion 26 and a communication position with respect to the passage intermediate portion 19c.

The valve train B will be briefly described. As shown in FIGS. 8, 10, and 12, the valve gear B includes a rocker arm shaft 28 that extends in the front-rear direction and is supported by a plurality of shaft support portions 2 a that are erected on the cylinder head 2, and a rocker. It comprises a plurality of rocker arms 29 and 30 (six in total) for supply and exhaust, which are pivotally supported by an arm shaft 28.

The rocker arms 29 and 30 include drive-side end portions 29a and 30a for operating a supply/discharge valve (not shown) and passive-side end portions 29b and 30b driven by a push rod (not shown). A push rod hole (not shown) is formed in the cylinder head 2 so as to pass the push rod. As shown in FIG. 8, the blow-by gas g passes through the push rod hole and the blow-by gas g inside the head cover 3. Will be sent to.

In the blow-by gas recirculation device A, the interior of the head cover 3 and the space 26 are partitioned by a bottom wall 25 having a discharge reed valve 31 and two return reed valves 34, 34, and the space 26 is a gasket. A communication hole 38 of 35 communicates with the cover intake passage 19A. Therefore, when the internal pressure of the head cover 3 is higher than the pressure of the cover intake passage 19A, the discharge reed valve 31 opens and the blow-by gas g in the head cover 3 passes through the discharge reed valve 31, the space 26, and the communication hole 38. It enters the passage intermediate portion 19c and is returned to the intake passage k.

Then, when the internal pressure of the head cover 3 and the pressure of the cover intake passage 19A are the same or the internal pressure of the head cover 3 is lower than the pressure of the cover intake passage 19A, the pair of return reed valves 34, 34 are opened, and the space portion is opened. The oil captured from the blow-by gas g at 26 is dropped into the head cover 3 through the return valve holes 33a and 33a. The dripping oil from the return valve hole 33a is not only returned to the inside of the engine, but also has a good lubricating function such as a sliding portion (not shown) between the rocker arm shaft 28 and the rocker arm 29, which is supplied to the valve gear B. Can also be obtained.

In the engine with a blow-by gas recirculation device according to the present embodiment, the cover intake passage 19A that is a part of the compressor upstream intake passage 19 is attached to the head cover 3, and the blow-by gas passage 26 of the blow-by gas outlet 3A and the cover intake passage 19A are attached. The passage intermediate portion 19c of the above is communicated through the communication hole 38 of the gasket 35. The head cover 3 is a portion where heat is conducted from the cylinder head 2 and becomes warm, and the blow-by gas g is returned to the cover intake passage 19A that is a part of the head cover 3 that becomes warm.

Therefore, even if the intake air a becomes cold due to extremely cold weather, the temperature of the air a flowing through the cover intake passage 19A is raised [see FIG. 11(A)]. The freezing of water in the water is eliminated or suppressed. As a result, it becomes possible to provide an engine with a blow-by gas recirculation device in which the end portion of the blow-by gas passage 26, which is connected to the intake system, is unlikely to be frozen, and the inconvenience caused by freezing at low temperatures is minimized. ..

The cover intake passage 19A is formed such that the passage end portion 19b is closer to the outer side (front side) in the head cover longitudinal direction with respect to the passage start end portion 19a. Specifically, the cover intake passage 19A extends in a direction (horizontal direction) intersecting the longitudinal direction (front-back direction) of the head cover 3 and is parallel to each other, and includes a passage start end portion 19a and a passage end portion 19b, and a passage start end portion 19a. It is formed to have a passage intermediate portion 19c which connects the start end of the passage end portion 19b.

Then, as shown in FIG. 6 and FIG. 11, the cover intake passage 19A is set to a meandering passage having a substantially Z shape (a crank shape or a bent shape) in a plan view. Due to the meandering of the cover intake passage 19A, as shown in FIG. 11(A), the blow-by gas g is recirculated to a position where the flow of the air a is changed and activated as compared with a straight line, so that the blow-by gas g is recirculated. There is an advantage that the antifreezing action is enhanced.

Since the passage end portion 19b is closer to the front side (outer side in the longitudinal direction of the head cover) than the passage start end portion 19a, if the cover intake passage 19A formed by the gas outlet cover 3B of the molded part is made a meandering passage, the structure is simply upstream of the compressor. There is an advantage that the shape of the suction passage 19 can be a non-linear passage. In addition, since the downstream side (passage end portion 19b) of the blow-by gas g in the compressor upstream suction passage 19 (passage intermediate portion 19c) is located closer to the front, the cooling action of the cooling air of the engine cooling fan 6 causes the passage. There is also an advantage that the temperature of the air supplied to the intake manifold 15 can be lowered by strengthening it from the starting end portion 19a.

The gas outlet cover 3B and its vicinity will be additionally described. As shown in FIGS. 10 and 11, the blow-by gas passage 26 and the cover intake passage 19A are communicated with each other by a communication hole 38 and a labyrinth-shaped communication passage 40. The communication passage 40 is configured by a gas passage recess 36a of the gas outlet cover 3B and a gasket 35 that serves as a lid that closes the opening. The gas passage recess 36a of the gas outlet cover 3B communicates with the downstream end of the passage intermediate portion 19c in the gas flow direction.

As shown in FIGS. 11(A) and 11(B), the gas passage recess 36a has a right end portion located above the communication hole 38 of the gasket 35 and a narrow front and rear connecting to the passage intermediate portion 19c. It has an end recess 42 oriented. Then, in the gas outlet cover 3B, a left protrusion wall 43 that projects rearward toward the gas passage recess 36a along the terminal recess 42, and a forward protrusion on the right side of the left protrusion wall 43 toward the gas passage recess 36a. The right protrusion wall 44 is formed. Therefore, the blow-by gas g flowing from the communication hole 38 passes through the communication passage 40, which is a path bent in a labyrinth-like (crank-like) shape by the right protruding wall 44 and the left protruding wall 43, and then proceeds to the passage intermediate portion 19c. Is configured.

As shown in FIGS. 11A and 11B, between the portion of the communication passage 40 excluding the end portion on the intake passage side (termination recess 42) and the cover intake passage 19A, more specifically, the passage intermediate portion 19c. A heat insulating part D is provided. The heat insulating portion D is configured by a curved elongated hole (an example of a recess or a hole) 41 formed in the gas outlet cover 3B in a state of opening on the gasket side surface of the gas outlet cover 3B, and the opening 41a of the curved elongated hole 41 is , And is covered with the gasket 35.

The curved elongated hole 41 is formed between the passage intermediate portion 19c and the gas passage recess 36a so as to be partitioned by the front and rear rib-shaped walls 45, 45 having a small thickness. Due to the existence of the gasket 35, the curved elongated hole 41 becomes a closed space portion, so that the space portion serves as an air layer and the heat insulating portion D is formed. Although the depth of the curved elongated hole 41 is formed deeper than the depth of the gas passage recess 36a, the depth is not limited to this.

Since the communication passage 40 that connects the space portion 26, which is a blow-by gas passage, and the passage intermediate portion 19c is not a straight passage but a labyrinth-like passage bent in zigzag, the intake passage k side (such as the air cleaner 23) ( Droplets (moisture and the like) from the passage intermediate portion 19c) have an effect that they are unlikely to enter the inside of the head cover 3. Then, the oil component in the blow-by gas becomes difficult to be drawn into the communication passage 40, and even if it is drawn in, it is shaken off by the labyrinth-like passage, and the oil removing action can be exerted.

Further, the communication passage 40 and the passage intermediate portion 19c are formed along the mutual shape, but since the heat insulating portion D is formed between these both 40 and 19c, the blow-by gas outlet portion 3A is In particular, the temperature in the vicinity of the communication passage 40 is less likely to drop due to intake air, and the effect of further reducing the risk of freezing can be obtained.

[Another embodiment]
The labyrinth-shaped communication passage 40 may be formed by the blow-by gas outlet portion 3A and the gasket 35. The heat insulating portion D may be provided on the rear side or the upper side of the communication passage 40.

1B Crankcase 3 Head cover 3B Gas outlet cover 19A Cover intake passage 26 Blow-by gas passage 35 Gasket 40 Communication passage 41 Recess or hole 41a Opening D Thermal insulation part k Intake passage

Claims (6)

Blow-by gas in the crankcase is configured to return to the intake passage after passing through the inside of the head cover,
The intake passage has a cover intake passage provided in the head cover, and the blow-by gas passage of the head cover and the cover intake passage are communicated with each other.
An engine with a blow-by gas recirculation device, wherein the blow-by gas passage and the cover intake passage are connected by a labyrinth-like communication passage. The engine with a blow-by gas recirculation device according to claim 1, wherein the cover intake passage is formed in a gas outlet cover detachably attached to the head cover. The blow-by gas recirculation device-equipped engine according to claim 2, wherein the communication passage is constituted by a gasket provided between the gas outlet cover and the head cover, and the gas outlet cover. The engine with a blow-by gas recirculation device according to any one of claims 1 to 3, wherein a heat insulating portion is provided between a portion of the communication passage other than an end portion on the intake passage side and the cover intake passage. The blow-by gas recirculation device engine according to claim 4, wherein the heat insulating portion is formed by a recess or a hole formed in the gas outlet cover in a state of opening on a side surface of the gasket of the gas outlet cover. The blow-by gas recirculation device equipped engine according to claim 5, wherein the opening of the recess or the hole is configured to be covered by the gasket.

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