JP2020109278A - Blow-by gas recirculation device - Google Patents

Abstract

To provide a blow-by gas recirculation device that has a gas inlet on an upper side of a valve movement mechanism but controls the gas inlet from sucking oil with a further structural innovation, thereby improving a gas passage inside a head cover so as to preferably function.SOLUTION: A blow-by gas recirculation device includes: a blow-by gas passage W which is formed inside a head cover 5 to lead a blow-by gas from a crankcase to an intake passage A through an inside of the head cover 5; a gas inlet i which is provided in the blow-by gas passage so as to be opened downward in the bottom part to lead the blow-by gas to the blow-by gas passage W; and a suctioning position lifting body 41 having one end communicated to the gas inlet i and the other end opened at an intermediate height position between a height position of the gas inlet i and a height position of an upper end inside the head cover 5.SELECTED DRAWING: Figure 5

Description

The present invention relates to a blow-by gas recirculation device applied to various engines, and relates to a blow-by gas recirculation device including a separator.

An industrial diesel engine or the like is generally provided with a blow-by gas recirculation device having a structure for returning blow-by gas to the intake passage from the inside of a cylinder head cover (hereinafter abbreviated as head cover).

In a structure in which blow-by gas flows through the inside of the head cover to the outside of the engine (to the intake passage), a gas passage is provided in the head cover above the valve operating mechanism. The gas passage in the head cover is equipped with a filter or a separator that captures an oil component from blow-by gas.

During engine startup, oil components such as filters, separators, and oil separated from blow-by gas passing through the gas passages are constantly accumulated, so the oil components trapped at the bottom of the gas passages are returned to the bottom. Parts are provided. As such examples, those disclosed in Patent Document 1 and Patent Document 2 are known.

JP 2012-57575 A JP, 2011-231686, A

In the head cover gas passage, a blow-by gas inlet is usually provided at the bottom of the gas passage, but since there is a valve operating mechanism below it, the scattered oil is easily sucked together from the gas inlet. There's a problem. If the amount of oil taken in and taken out increases, the amount of engine oil will decrease at an early stage, which is not good.

The object of the present invention is to improve the structure of the gas passage in the head cover so as to suppress the oil suction from the gas inlet even though it has the gas inlet on the upper side of the valve mechanism by further structural improvement. Thus, an improved blow-by gas recirculation device is provided.

The present invention is 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,
The blow-by gas passage formed in the head cover is provided with a gas inlet opening downward at the bottom thereof to guide the blow-by gas to the blow-by gas passage,
A suction position lifting body is provided, one end of which is communicated with the gas inlet, and the other end of which is opened at a height position intermediate between the height position of the gas inlet and the height position of the upper end inside the head cover. It is characterized by

For example, it is convenient that the suction position lifting body includes a lifting passage having a J-shaped or L-shaped cross-sectional shape by covering the lower side and the lateral side of the gas inlet. The suction position lifting body may use a wall of the head cover and/or a partition wall for forming the blow-by gas passage as a component forming the lifting passage. The blow-by gas recirculation device according to any one of claims 1 to 3, wherein the opening position of the other end of the suction position lifting body is set near the upper end inside the head cover.

Further, inside the head cover, a separator having a separator inlet for introducing blow-by gas, a filter, an oil drop portion, and a separator outlet for discharging blow-by gas is incorporated, and the gas inlet is defined by the separator inlet. It may be configured.

According to the present invention, by providing the suction position lifting body, it is possible to substantially set the position of the gas inlet to a position higher than in the conventional case. Therefore, even if the oil is scattered by the valve mechanism, it is pulled up. It becomes difficult to reach the gas inlet, and the oil is clearly reduced from being sucked in from the gas inlet.

As a result, although the valve operating mechanism has a gas inlet, the oil suction from the gas inlet is suppressed, and the blow-by gas recirculation device improved so that the gas passage in the head cover functions well. Can be provided.

For example, if the suction position lifting body is provided with a lifting passage having a J-shaped or L-shaped cross section by covering the lower side and the lateral side of the gas inlet, blow-by gas easily enters the gas inlet, and scattered oil is scattered. Has a merit that it is more difficult to enter the gas inlet, and the aforementioned effects can be enhanced.

(A) A sectional view of the front portion of the head cover cut vertically at the site of the gas inlet opening, and (B) A sectional view of the gas outlet portion cut vertically at the slightly left side of the gas inlet opening. Top view of head cover separately Top view of industrial diesel engine Top view of separator Left side view of separator

Hereinafter, a case where the embodiment of the blow-by gas recirculation device according to the present invention is applied to a small industrial diesel engine will be described 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 (not shown). An assembled head cover, 6 is a plurality of injectors, and 7 is a fuel injection supply pump.

The engine E is equipped with a blow-by gas recirculation device (not shown), and blow-by gas from a crankcase (not shown) is formed inside the head cover 5 to form a blow-by gas passage W (see FIG. 1). Through which the oil component is removed as much as possible and is returned to the intake passage A. An example of the intake passage A is the intake side duct 3A of the supercharger 3 (see FIG. 4).

As shown in FIGS. 3 and 4, the head cover 5 includes an upper and lower intermediate wall 5C having four circular holes 5a for mounting injectors, a front upper wall (hereinafter referred to as a head cover upper wall) 5A, and a rear wall. It is a bottomless box-shaped member having a side upper wall 5B. A gas outlet portion 8 is formed in the rear portion of the head cover upper wall 5A so as to project upward from the head cover upper wall 5A. A gas pipeline 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 passage.

A separator (oil separator) S shown in FIG. 4 is housed under the head cover upper wall 5A. The plan view shape of the separator S is formed in a substantially lateral T shape so as to fit inside the head cover upper wall 5</b>A so as to fit perfectly inside. Insertion holes 24 for bolting and mounting the head cover 5 are formed on the front and rear sides and on the right side of the separator S, respectively.

In the separator S, a blow-by gas inlet, that is, a separator inlet 10 is formed at a front end portion of a lower surface, and a blow-by gas outlet, that is, a separator outlet 11 is formed at a rear end portion of an upper surface. An oil drop portion 12 that largely protrudes downward is formed at a position on the right side of the separator S in the front-rear direction, and a filter (not shown) is provided between the separator inlet 10 and the oil drop portion 12 in the front-rear direction. Has been.

Therefore, the blow-by gas g from the crankcase enters the inside of the separator S from the front end portion inside the head cover 5 through the separator inlet 10 at the front end portion of the lower surface of the separator S, and is subjected to a filter action and an oil dropping action there, It flows out from the separator outlet 11 at the rear end of the upper surface of the separator S.

As shown in FIG. 1A, the separator outlet 11 is airtightly arranged to face the gas inlet opening 14 of the gas outlet portion 8 of the head cover 5. Therefore, the blow-by gas g emitted from the separator outlet 11 passes through the gas outlet portion 8 and then flows into the gas pipeline 9. That is, the blow-by gas passage W inside the head cover 5 is also formed inside the separator S accommodated therein.

As shown in FIG. 1(A), FIG. 2 and FIG. 3, the gas outlet portion 8 has a protruding case portion 15 that bulges 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 protruding case portion 15. In FIG. 1A, 5D is a front wall of the head cover.

The protruding 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. The upright wall 17, the rear wall 19, and the take-out wall 20 are formed as inclined walls with an inclined angle, and the protruding case portion 15 has a hem-spread appearance. An eave wall 20A having an outlet opening 22 of the outlet passage 8A is formed on the take-out wall 20 having an outer surface (not shown) facing slightly left rear.

The protruding case portion 15 includes a passage wall 15B that protrudes downward inside the head cover 5, and the passage wall 15B is formed with an outlet passage 8A having an L-shape whose side view is upside down. There is. The outlet passage 8A is formed as a bent passage having a vertical passage portion 8a having a gas inlet opening 14 at a lower end and a lateral passage portion 8b having an outlet opening 22 at a left end (tip). As shown in FIG. 1, a rib wall 23 is formed on the back side of the lower end of the standing wall 17 so as to project downward in a range that does not interfere with the separator S.

Therefore, as shown in FIGS. 1(A) and 1(B), the air is stretched between the standing wall 17 and the passage wall 18 rising from the upper wall 5A of the head cover at the inclination angle θ and the rib wall 23. The layer 16 is formed. An air layer 16 is also formed between the rear wall 19 and the passage wall 18. Further, as shown in FIG. 4, the standing wall 17 is configured with the protruding case portion 15 so as to face the upstream side in the flow direction of the engine cooling air R (direction of arrow Y).

With the head cover configured as described above, the following operational effects can be obtained. An air layer 16 is formed around the passage wall 15B projecting downward of the gas outlet portion 8 projecting from the head cover upper wall 5A as a blazer path of the head cover 5 and between the standing wall 17 which is an outer wall. The standing wall 17 is an inclined wall that is angled from the horizontal.

In other words, the conventional product has a single wall, but the present embodiment has a double-wall structure (passage wall 15B, standing wall 17) with the air layer 16 provided therebetween, so that the heat insulating effect is significantly improved. Come to do. Therefore, the temperature of the outlet passage 8A is prevented from lowering even in cold weather such as extremely cold, and the moisture in the blow-by gas is cooled to cause dew condensation, and in some cases, it is not frozen.

Further, the protruding case portion 15 is located on the lee side of the engine cooling air R generated by the engine cooling fan 1, so that the standing wall 17 is directly exposed to the engine cooling air R. However, since the standing wall 17 is a slanted wall having the tilt angle θ, the engine cooling air R smoothly blows off the standing wall 17 as shown by the arrow in FIG. 1(A). Therefore, the cooling effect of the engine cooling air R can be minimized or greatly suppressed.

As a result, due to the structural improvement, the blow-by gas g in the gas outlet portion 8 formed in the protruding case portion 15 becomes difficult to cool, and an improved cylinder is provided so as to prevent freezing or clogging at the gas outlet during cold weather. A head cover 5 can be provided.

[Embodiment 1]
As shown in FIGS. 1A, 4 and 5, the blow-by gas passage W formed in the head cover 5 has a gas inlet that opens downward at the bottom of the blow-by gas passage and guides the blow-by gas to the blow-by gas passage W. i is provided, one end of which is communicated with the gas inlet i, and the other end of which is opened at a height intermediate between the height of the gas inlet i and the height of the upper end inside the head cover 5. A lifting body 41 is provided.

As an example, as shown in FIGS. 4 and 5, the suction position lifting body 41 includes a left side wall 41a, a right side wall 41b, a front wall 41c, a bifurcated rear wall 41d, and a bottom wall 14e connected to all of them. Is formed into a substantially lidless box-shaped member. The left and right side walls 41a and 41b are slightly lower than the upper surface of the separator S, but extend to a higher position near the upper wall 5A of the head cover 5. The front wall 41c has a height in contact with the bottom surface 5e of the thick cover portion 5E for bolting the separator S, and the front wall 41c and the thick wall portion 5E of the separator S are separated from the side wall b of the separator S. A front lifting passage 42(t) is formed narrow in the front-rear direction, wide in the left-right direction, and elongated in the upper-lower direction.

Between the left and right side walls 41a, 41b and the side wall b of the separator S, left and right lifting passages 43(t), 44(t) that are long in the up and down direction and long in the front and back direction and narrow in the left and right direction are formed. Further, between the bottom wall 14e and the bottom wall b of the separator S (separator inlet 10), there is formed a flat passage 45(t) that is wide in the front and rear, left and right, and narrow in the top and bottom. The rear wall 41d is a wall for closing the rear ends of the left and right lifting passages 43, 44 and the flat passage 45.

Since the suction position lifting body 41 that surrounds the front end portion of the separator S is provided inside the head cover 5, the blow-by gas g must ride over the upper ends of the left and right side walls 41a and 41b, and three places after that. It is possible to reach the separator inlet 10 (gas inlet i) only after moving downward and laterally through the lifting passage t, which is a narrow space portion of. When viewed from the separator inlet 10, a lifting passage t having a J shape or an L shape like a snorkel is formed.

That is, the suction position lifting body 41 uses the wall 5D of the head cover 5 and/or the partition wall (side wall of the separator S, bottom wall) b for forming the blow-by gas passage W as a component forming the lifting passage t. ing. The upper ends of the left and right side walls 41a41b at the opening position at the other end of the suction position lifting body 41 are set near the upper ends inside the head cover 5 (see FIG. 5).

As described above, by using the suction position lifting body 41, the inlet of the blow-by gas g can be substantially pulled up at the height h (see FIG. 5) while keeping the position of the separator inlet 10. Therefore, even if the oil is scattered by the valve operating mechanism, the gas inlet i is substantially lifted up to the vicinity of the upper end inside the head cover 5, so that the oil component is drastically reduced together with the blow-by gas g.

The blow-by gas g, which is lighter than the oil component, passes over the suction position lifting body 41 and easily approaches the gas inlet i, so that the blow-by gas passage W can be smoothly advanced. As a result, the blow-by gas passage W in the head cover 5 is improved so that the oil suction from the gas inlet i is suppressed even though the gas inlet i is provided on the upper side of the valve mechanism. The blow-by gas recirculation device B can be provided.

[Another embodiment]
The suction position lifting body 41 shown in FIGS. 4 and 5 covers the entire separator inlet 10 to form the lifting passage t. However, the suction position lifting member having a structure that functions for a half of the separator inlet 10 or an area of ⅔ The body 41 may be used.

5 Head Cover 5D Wall 10 Separator Inlet 11 Separator Outlet 12 Oil Dropper 41 Suction Position Lifting Body A Intake Passage S Separator W Blow-by Gas Passage b Partition Wall i Gas Inlet t Lifting Passage

Claims (5)

It is configured to guide blow-by gas from the crankcase to the intake passage through the inside of the head cover,
The blow-by gas passage formed in the head cover is provided with a gas inlet opening downward at the bottom thereof to guide the blow-by gas to the blow-by gas passage,
A suction position lifting body is provided, one end of which is communicated with the gas inlet, and the other end of which is opened at a height position intermediate between the height position of the gas inlet and the height position of the upper end inside the head cover. Blow-by gas recirculation equipment. The blow-by gas recirculation device according to claim 1, wherein the suction position lifting body is provided with a lifting passage having a J-shaped or L-shaped cross section by covering the lower side and the lateral side of the gas inlet. The blow-by gas recirculation device according to claim 2, wherein the suction position lifting body uses a wall of the head cover and/or a partition wall for forming the blow-by gas passage as a component forming the lifting passage. .. The blow-by gas recirculation device according to any one of claims 1 to 3, wherein an opening position of the other end of the suction position lifting body is set near an upper end inside the head cover. Inside the head cover, a separator having a separator inlet for introducing blow-by gas, a filter, an oil dropping part, and a separator outlet for discharging blow-by gas is incorporated, and the gas inlet is constituted by a separator inlet. The blow-by gas recirculation device according to any one of claims 1 to 4,

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