JP7148417B2 - Blow-by gas reflux device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blow-by gas recirculation device applied to various engines, and more particularly to a blow-by gas recirculation device provided with an oil separator.

2. Description of the Related Art Many industrial diesel engines and the like are provided with a blow-by gas recirculation device that returns blow-by gas to an intake path after passing through the inside of a cylinder head cover (hereinafter abbreviated as head cover).

When the blow-by gas is caused to flow outside the engine (to the intake passage) through the inside of the head cover, a gas passage is provided above the valve mechanism inside the head cover. Since the gas passage inside the head cover tends to be a narrow flat passage in the vertical direction, an oil separator that captures the oil component from the blow-by gas is generally provided outside the head cover as a dedicated component (for example, Patent Document 1: ).

The structure in which the oil separator is arranged on the side of the cylinder block has the advantage of being able to have a sufficient capacity because there is almost no space limitation as in the inside of the head cover. However, since the oil separator, which is a dedicated part, is added as an engine accessory, there are the following disadvantages.

(1) The size (bulkness) of the engine as a whole increases due to the addition of the oil separator. (2) Since the gas passage from the head cover to the intake passage becomes long and the length of the external piping also becomes long, the possibility of freezing of the moisture contained in the blow-by gas in cold weather increases.

JP 2018-35787 A

An object of the present invention is to provide a passage for blow-by gas in the head cover and to provide an oil separator by means of structural improvements, while suppressing an increase in the size of the engine and shortening the length of the external pipe for blow-by gas. It is therefore an object of the present invention to provide a blow-by gas recirculation system which is improved so as to avoid the aforementioned possibility of freezing as much as possible.

The present invention provides a blow-by gas recirculation device,
It is configured to guide blow-by gas from the crankcase to the intake passage through the inside of the head cover,
an oil separator mounted inside the head cover for capturing and removing oil from blow-by gas;
An oil dropping portion for discharging captured oil projects downward from the oil separator, and a check valve is provided at the lower end of the oil dropping portion to allow the oil to move downward and prevent the oil from moving upward. provided ,
The check valve is an umbrella valve having a flow path and a valve mounting hole formed in the bottom wall of the oil dropping portion and having a lower surface of the bottom wall as a seat surface,
The umbrella valve includes an umbrella portion that abuts against the lower surface, and a support shaft portion that extends upward from the umbrella portion and is inserted into the valve mounting hole, and extends downward from the umbrella portion to receive the oil. It is characterized by having a guide projection reaching an oil reservoir formed below the dropper .

Preferably, the oil dropping portion protrudes toward a clearance portion of a valve mechanism provided inside the head cover.

The oil separator preferably includes a separator inlet for introducing blow-by gas, a filter, the oil dropping section, and a separator outlet for discharging blow-by gas.

Further, it is convenient that the head cover is formed with a gas outlet portion, which is the outlet of the blow-by gas, and the separator outlet of the oil separator is overlapped with the opening of the gas outlet portion on the inner side of the head cover, and the oil separator is: It is more convenient if it is detachably bolted to the head cover.

According to the present invention, since the oil separator is built in (accommodated) in the head cover, the volume of the engine as a whole can be reduced compared to the structure (conventional structure) in which the oil separator is arranged as a dedicated part outside the head cover. becomes possible. In addition, since the external piping for the blow-by gas from the head cover to the oil separator can be omitted, there is an advantage that the possibility of the water content in the blow-by gas freezing in the external piping during cold weather can be avoided.

In addition, since a check valve is provided at the lower end of the oil drop portion projecting downward from the oil separator, the risk of oil being sucked up again after gas-liquid (gas component and oil component) separation of the blow-by gas is eliminated. There is an advantage that the oil discharge property becomes good.

As a result, an oil separator with a check valve is provided at the blow-by gas passage and the oil return port in the head cover. It is possible to provide an improved blow-by gas recirculation device in which the length is shortened to minimize the possibility of freezing as described above.

(A) Cross-sectional view of the front part of the head cover cut vertically at the gas inlet opening, (B) Cross-sectional view of the gas outlet cut vertically slightly to the left of the gas inlet opening. Top view of single head cover Top view of an industrial diesel engine Top view of oil separator Bottom view of oil separator Left side view of oil separator The lower end of the oil dropping part is shown, (A) is a bottom view, (B) is a cross-sectional view of the umbrella valve,

DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where an embodiment of a blow-by gas recirculation device according to the present invention is applied to a small industrial diesel engine will be described below with reference to the drawings.

A plan view of an industrial diesel engine E is shown in FIG. 3, where 1 is an engine cooling fan, 2 is an alternator, 3 is a supercharger, 4 is an exhaust treatment device, and 5 is a cylinder head 41 (see FIG. 6). A head cover is assembled thereon, 6 is a plurality of injectors, and 7 is a fuel injection supply pump.

As shown in FIG. 1, the engine E is equipped with a blow-by gas recirculation device B, which allows blow-by gas g from a crankcase (not shown) to flow through a blow-by gas passage W formed inside the head cover 5. , and returns to the intake passage A in a state in which oil components and the like are removed as much as possible. An example of the intake passage A is an intake side duct 3A of the supercharger 3 (see FIG. 3).

As shown in FIGS. 2 to 4, the head cover 5 includes an upper and lower intermediate wall 5C having four circular holes 5a for mounting injectors, a head cover upper wall 5A as a front upper wall, and a rear upper wall. 5B is a bottomless box-shaped member. A gas outlet portion 8 is formed in a rear portion of the head cover upper wall 5A so as to protrude upward from the head cover upper wall 5A. A gas pipe line 9 for returning the blow-by gas g to the intake passage A is connected to the gas outlet portion 8 which is also a blazer line.

[Embodiment 1]
A blow-by gas recirculation device B, which is also a CCV (crankcase ventilation), has an oil separator S housed under the head cover upper wall 5A, as shown in FIG. 1(A). As shown in FIG. 4, the oil separator S is formed in a substantially horizontal T-shape so that it can fit snugly inside the head cover upper wall 5A in accordance with the upward protruding shape of the head cover upper wall 5A. Insertion holes 24 for bolting to the inside of the head cover 5 are formed in the front, rear, and right sides of the oil separator S, respectively.

As shown in FIG. 1(A) and FIGS. 4 to 6, the oil separator S has an inlet for blow-by gas, that is, a separator inlet 10, at the front end of its lower surface, and an inlet for blow-by gas at the rear end of its upper surface. An outlet or separator outlet 11 is formed. An oil dropping portion 12 that protrudes greatly downward is formed on the right side of the oil separator S in the middle of the front and rear. there is

Therefore, the blow-by gas g from the crankcase advances to the front end inside the head cover 5 and enters the inside of the oil separator S through the separator inlet 10 at the front end of the lower surface of the oil separator S. After receiving the dripping action, the oil flows out from the separator outlet 11 at the rear end of the upper surface of the oil separator S. That is, the upper part of the inside of the head cover 5 and the inside of the oil separator S form the blow-by gas passage W. As shown in FIG.

As shown in FIG. 1A, the separator outlet 11 is arranged opposite to the gas inlet opening 14, which is the opening on the inside of the head cover 5, of the gas outlet portion 8 of the head cover 5, and is hermetically sealed by interposing an annular seal member 37. are superimposed. Therefore, the blow-by gas g coming out of the separator outlet 11 flows through the gas outlet 8 and then into the gas pipeline 9 .

As shown in FIGS. 1A, 2, and 3, the gas outlet portion 8 has a protruding case portion 15 protruding upward from the head cover upper wall 5A to form an outlet passage 8A through which the blow-by gas g passes. An air layer 16 is formed outside the outlet passage 8A in the projecting case portion 15. As shown in FIG. In addition, in FIG. 1(A), 5D is a front wall of the head cover.

The projecting case portion 15 has a top wall 15A, a front standing wall 17, a rear wall 19, a left extraction wall 20, and a right side wall 21. As shown in FIG. The upright wall 17, the rear wall 19, and the take-out wall 20 are formed as inclined walls with an inclination angle, and the projecting case portion 15 has an appearance that spreads toward the bottom. An eaves wall 20a having an outlet opening 22 of the outlet passage 8A is formed on the take-out wall 20 having an outer surface (notation omitted) facing slightly to the left rear.

The protruding case portion 15 is provided with a passage wall 18 that protrudes downward inside the head cover 5. The passage wall 18 is formed with an outlet passage 8A having an upside-down L-shape when viewed from the side. there is The outlet passage 8A is formed in a bent passage having a vertical passage portion 8a having a gas inlet opening 14 at its lower end and a lateral passage portion 8b having an outlet opening 22 at its left end (tip). A rib wall 23 is formed on the rear side of the lower end portion of the standing wall 17 and protrudes downward within a range that does not interfere with the oil separator S, as shown in FIG.

As shown in FIGS. 1A and 1B, the air layer 16 extends between the standing wall 17 rising from the head cover upper wall 5A at an inclination angle θ, the passage wall 18, and the rib wall 23. is formed. An air layer 16 is also formed between the rear wall 19 and the passage wall 18 . Further, as shown in FIG. 3, the protruding case portion 15 is configured such that the standing wall 17 faces the upstream side in the flow direction of the engine cooling air R (the arrow Y direction).

The head cover configured as described above provides the following effects. An air layer 16 is formed around a passage wall 18 protruding downward from the gas outlet portion 8 protruding from the head cover upper wall 5A as a blazer passage of the head cover 5 and an upright wall 17 which is an outer wall. The standing wall 17 is an inclined wall with an angle from the horizontal.

In other words, where the conventional product had a single wall, the present embodiment has a double-wall structure (passage wall 18, standing wall 17) with an air layer 16 between them, so that the heat insulating effect is greatly improved. will come to Therefore, the temperature drop in the outlet passage 8A is suppressed even in cold weather such as extreme cold, and moisture in the blow-by gas is cooled to cause dew condensation, and in some cases, freezing does not occur.

The projecting case portion 15 is located on the lee side of the engine cooling airflow R from the engine cooling fan 1 , and the standing wall 17 is directly exposed to the engine cooling airflow R. As shown in FIG. However, since the standing wall 17 is inclined at the inclination angle θ, the engine cooling air R smoothly blows away the standing wall 17 as indicated by the arrow in FIG. 1(A). , the cooling effect of the engine cooling air R can be minimized or greatly suppressed.

As a result, by structurally devising, the blow-by gas g at the gas outlet portion 8 formed in the protruding case portion 15 is hardly cooled, and the head cover is improved so that the gas outlet is not frozen or clogged in cold weather. 5 can be provided.

As shown in FIGS. 1A, 4, and 5, the blow-by gas passage W formed in the head cover 5 has a gas inlet opening downward at the bottom thereof for guiding the blow-by gas to the blow-by gas passage W. An oil intake restriction mechanism C is provided at or below the gas inlet i to restrict or restrict oil intake from the gas inlet i. The oil intake restriction mechanism C is configured with a louver 32 covering the gas inlet i.

The louver 32 is configured by supporting a plurality of louver plates 33 aligned in the same longitudinal direction so as to enter the separator inlet 10 (gas inlet i). The plurality of blades 33 are inclined in the left-right direction, for example, with the left side being the bottom. It is defined as a crossing direction (horizontal direction).

For example, the housing 35 of the oil separator S is formed by molding a synthetic resin material (injection molding or blow molding is also possible), and the plurality of blades 33 can also be formed during the molding. Also, although not shown, the separator inlet 10 having a rectangular opening may be equipped with a separate louver embedded therein. A separator inlet 10 is a gas inlet i as an internal space portion of the oil separator S in the blow-by gas passage W inside the head cover 5 . An opening (not shown) for installing a relief valve (not shown) using a coil spring may be provided below the separator outlet 11 of the oil separator S [see FIG. 1(A)].

Since the separator inlet 10 (gas inlet i) that opens downward has the valve mechanism 38 below it, the positional relationship is such that splashed oil is easily sucked from the separator inlet 10 . However, in the present invention, since the oil intake regulation mechanism C comprising the louver 32 is provided at the separator inlet 10, even if the oil is splashed by the valve mechanism 38, it is repelled by the plurality of blades 33 and the oil is retained. Leaving will be greatly reduced.

Since the blow-by gas g enters the oil separator S from the plurality of inclined openings 34, it can proceed through the blow-by gas passage W smoothly. As a result, even though the valve mechanism 38 has the gas inlet i on the upper side, oil intake from the gas inlet i is suppressed. Therefore, the blow-by gas passage W in the oil separator S built in the head cover 5 constitutes a blow-by gas recirculation device B that functions well in separating the oil.

As shown in FIGS. 4 to 6, below the gas inlet i (separator inlet 10), there is provided a labyrinth tool 51 that makes the flow of the blow-by gas g toward the gas inlet i a labyrinthine state. The labyrinth tool 51 has a cover plate 52 arranged in a recumbent position below the gas inlet i. The cover plate 52 is set to have a size larger than the gas inlet i when viewed in the front-rear direction. ing.

The cover plate 52 is supported on the oil separator S by a plurality of stays 53 at a height slightly below the gas inlet i. The stay 53 is rod-shaped, and the vertical space between the separator bottom surface 54 having the gas inlet i and the cover plate 52 is sufficiently open in the front, rear, left, and right directions.

Without the cover plate 52, the blow-by gas g can easily enter the oil separator S through the wide opening of the gas inlet i. , the blow-by gas g advances to the gas inlet i while largely detouring from the front, back, left, and right.

Therefore, even if the oil component, which has a large inertial mass, advances from the lateral direction, it cannot bend completely, and instead of entering the gas inlet i, it advances straight. However, even with the cover plate 52, the blow-by gas (gas component) g, which has a small inertial mass, can smoothly bend and enter the oil separator S through the gas inlet i (separator inlet 10). Note that the oil separator S without the cover plate 52 may be used.

As shown in FIGS. 1(A), 5, and 6, the downwardly protruding oil dropping portion 12 of the oil separator S includes a lower protruding portion 12A that protrudes most downward, and a lateral (left ) and an intermediate protrusion 12B between the two 12A and 12C, and the lower protrusion 12A is formed with a lower end opening 12a. The oil dropping portion 12 protrudes toward a gap 39 between the valve trains 38 provided inside the head cover 5, and has upper, middle, and lower protrusions corresponding to the shape of the valve train 38. Parts 12A, 12B and 12C are formed.

As shown in FIGS. 5 to 7, a check valve V is provided at the lower end of the oil dropping portion 12 for discharging the captured oil, allowing the oil to move downward and prevent the oil from moving upward. . The check valve V is formed with a flow path 26 and a valve mounting hole 12a in the bottom wall 25 of the oil dropping portion 12, and is composed of an umbrella valve 13 having a lower surface 25a of the bottom wall 25 as a seat surface.

The umbrella valve 13 has an umbrella portion 13A, a spindle portion 13B, and a guide protrusion 13C. The head portion 13A is a portion that abuts against the lower surface 25a, and the support shaft portion 13B is a portion that extends upward from the head portion 13A and is inserted into the valve mounting hole 12a. The guide projection 13C is a portion extending downward from the umbrella portion 13A so as to reach an oil reservoir 27 formed below the oil dropping portion 12. As shown in FIG. The oil reservoir portion 27 is oil that is accumulated in the head cover 5 with the upper surface 2a of the cylinder head 2 as the bottom, and is configured such that the lower end of the guide projection 13C is positioned below the oil oil surface 27a.

As shown in FIGS. 7A and 7B, a hook portion 13b is formed on the support shaft portion 13B. The hook portion 13b and the umbrella portion 13A serve as upper and lower hooks for the fitting portion between the shaft portion 13B and the valve mounting hole 12a, and the umbrella valve 13 is mounted on the bottom wall 25 in a stable state.

The flow path 26 of the bottom wall 25 is an arc-shaped hole formed at four locations around the valve mounting hole 12a, and is set to a size that is covered by the umbrella portion 13A when viewed from the top and bottom direction. When the umbrella valve 13 is attached to the bottom wall 25 using the valve attachment hole 12a, the four flow paths 26 are sealed by the umbrella portion 13A, and the internal space 28 of the oil dropping portion 12 has a certain amount of oil. When oil accumulates, the umbrella portion 13A moves downward due to the weight of the oil acting from the flow path 26, and seeps out from between the lower surface 25a.

Since the umbrella valve 13 is provided with the guide projection 13C whose lower end is located below the oil level 27a, surface tension can move the oil, which is a viscous fluid. Therefore, even if almost no oil remains in the internal space 28, the oil can move between the head portion 13A and the lower surface 25a by capillary action, and the oil captured by the oil separator S can be removed even when the valve is closed. The oil can be discharged downward from the oil dropping portion 12. - 特許庁That is, the guiding projection 13C breaks the surface tension of the flow path 26, which is the discharge hole, so that the oil can be discharged more smoothly than in a general umbrella valve.

The excess space in the head cover 5 is well utilized to compactly incorporate the oil separator S, so that the oil captured by the oil separator S can be returned to the engine from the lowest possible position (umbrella valve 13). It is Therefore, there is an advantage that the oil emitted from the umbrella valve 13 is prevented from scattering and the oil splashed by the valve mechanism 38 is prevented from flowing back from the flow path 26 to the internal space 28 of the oil dropping portion 12 .

The oil separator S, which is detachably incorporated in the head cover 5 by means of bolts 40, is incorporated in the head cover 5 on the side (front side) where the engine cooling fan 1 is arranged. 1 is formed at the end on the arrangement side (front side).

As described above, in the blow-by gas recirculation device B, an oil separator S for capturing and removing oil from the blow-by gas g is attached to the blow-by gas passage W formed in the head cover 5. The separator outlet 11 is superimposed on the gas inlet opening 14 of the part 8 . By doing so, it is only necessary to assemble the oil separator S inside the head cover 5 with the three bolts 40, and the assembling and mounting properties are excellent.

In other words, since the oil separator S is built in (accommodated) in the head cover 5, it is possible to reduce the bulk of the engine as a whole compared to the structure (conventional structure) in which the oil separator is arranged as a dedicated part outside the head cover. is. In addition, since the external piping for the blow-by gas from the head cover to the oil separator can be omitted, there is the advantage of avoiding the possibility that the moisture in the blow-by gas will freeze in the external piping in cold weather.

The blow-by gas recirculation device B according to the present invention also provides the following effects (1) to (4).
(1) Since the oil separator S is box-shaped and accommodated inside the head cover 5 with a gap, the outside air temperature does not directly reach the oil separator S, and it is difficult to cool even in cold weather.
(2) Conventionally, external piping was required from the head cover to the exterior oil separator, but in the present invention, such external piping can be omitted.
(3) Since the oil separator S is built in the head cover 5, there is no need to assemble any parts in the external appearance of the engine, which facilitates assembly.
(4) Since the check valve V (umbrella valve 13) is provided at the lower end of the oil dropping portion 12, the oil discharged from the oil separator S or the oil scattered by the valve mechanism 38 is discharged from the oil dropping portion. There is no reverse flow into 12, and the oil can be drained more smoothly.

[Another embodiment]
The check valve V installed in the oil dropping portion 12 may be of another structure such as a ball type or a poppet type other than the umbrella valve 13 .

5 Head cover 8 Gas outlet 10 Separator inlet 11 Separator outlet 12 Oil dropping part 12a Valve mounting hole 13 Umbrella valve 13A Umbrella part 13B Support shaft part 13C Guide projection 14 Head cover inner side opening 25 Bottom wall 25a Lower surface (seat surface)
26 Flow path 27 Oil reservoir 36 Filter 38 Valve mechanism 39 Gap part A Intake passage S Oil separator V Check valve

Claims (5)

It is configured to guide blow-by gas from the crankcase to the intake passage through the inside of the head cover,
an oil separator mounted inside the head cover for capturing and removing oil from blow-by gas;
An oil dropping portion for discharging captured oil projects downward from the oil separator, and a check valve is provided at the lower end of the oil dropping portion to allow the oil to move downward and prevent the oil from moving upward. provided ,
The check valve is an umbrella valve having a flow path and a valve mounting hole formed in the bottom wall of the oil dropping portion and having a lower surface of the bottom wall as a seat surface,
The umbrella valve includes an umbrella portion that abuts against the lower surface, and a support shaft portion that extends upward from the umbrella portion and is inserted into the valve mounting hole, and extends downward from the umbrella portion to receive the oil. A blow-by gas recirculation device provided with a guide projection reaching an oil reservoir formed below the dropper . 2. The blow-by gas recirculation device according to claim 1 , wherein said oil dropping portion protrudes toward a clearance portion of a valve mechanism provided inside said head cover . 3. The blow-by gas recirculation device according to claim 1, wherein said oil separator comprises a separator inlet for introducing blow-by gas, a filter, said oil dropping section, and a separator outlet for discharging said blow -by gas. 4. The head cover according to any one of claims 1 to 3, wherein a gas outlet portion that is an outlet for the blow-by gas is formed in the head cover, and a separator outlet of the oil separator overlaps an opening of the gas outlet portion on the inside of the head cover. blow-by gas recirculation device. The blow-by gas recirculation device according to any one of claims 1 to 4 , wherein the oil separator is detachably bolted to the head cover .

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