JP5304542B2 - Oil mist separator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil mist separator capable of reducing a pressure loss in oil mist including gas of a gas flow passage. <P>SOLUTION: A gas inflow port 14 is formed on one side of a bottom wall 13a of a housing 13 for constituting the oil mist separator 11, and a gas outflow port 15 is formed on one side of an upper wall 13b of the housing 13. First-third separation plates 17, 19 and 21 are arranged inside the gas flow passage 16, and a movable filter unit 25 is installed on the downstream side of the third separation plate 21. A flow speed of blow-by gas flowing in the gas flow passage 16 quickens, and when pressure acting on a filter 28 of the movable filter unit 25 increases, the filter 28 is turned in the clockwise direction around a rotary shaft 26, and flow resistance of the blow-by gas is properly held. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an oil mist separator that separates an oil mist from an oil mist-containing gas such as an engine blow-by gas.

  Generally, an engine is provided with a PCV (positive crankcase ventilation) for collecting blowby gas flowing out from a combustion chamber into the crankcase without releasing it into the atmosphere. The blow-by gas is returned from the crankcase to the intake system by the PCV, and the blow-by gas is combusted. Normally, oil is present as fine particles (oil mist) in blow-by gas. Therefore, in order to separate the oil mist from the blow-by gas and return it to the crankcase without burning the blow-by gas as is, Mist separation means are used. For example, in the conventional configuration disclosed in Patent Document 1, as shown in FIG. 10, a case member 52 is attached to the inner wall of the rocker cover 51 of the engine, and a separation chamber 53 is defined therein, and the separation chamber 53 is formed. An inlet hole 54 is formed on one side of the bottom wall of the bottom wall, and a drain pipe body 55 is suspended from the other side. A gas outlet 56 is formed on the upper wall of the separation chamber 53. Filter members 57 are erected at two locations in the separation chamber 53. A plurality of variable openings 59 are rotatably supported on the upstream side of each filter member 57 via a plurality of shafts 58. The variable opening 59 is held at the shielding position of the gas flow path by the elastic body 60. When the oil mist-containing gas is supplied from the inlet hole 54 to the separation chamber 53, the flow pressure causes the variable opening 59 to be displaced from the shield position indicated by the solid line to the open position indicated by the two-dot chain line. It has become.

JP-A-7-243318

  However, the conventional oil mist separator has the following problems. That is, the variable opening 59 is opened around the shaft portion 58 by the flow pressure of the oil mist-containing gas flowing in the separation chamber 53. For this reason, the oil mist-containing gas sprayed on the filter member 57 is concentrated in a limited portion of the filter member 57, that is, a position corresponding to the lower portion of the shaft portion 58, and the filter member 57 is quickly clogged. There is a possibility that the flow resistance of the oil mist-containing gas increases and the pressure loss increases.

  The present invention has been made paying attention to such problems existing in the prior art. The object is to provide an oil mist separator capable of reducing the pressure loss of the oil mist-containing gas.

  In order to solve the above problems, the invention according to claim 1 is characterized in that an oil mist-containing gas inlet hole is formed in the bottom wall of the separation chamber, and a filter for separating the oil mist is disposed in the separation chamber. In the oil mist separator provided with an oil discharge hole separated in the bottom wall of the separation chamber, when the flow resistance of the oil mist-containing gas when passing through the slit through the filter increases, the separation The gist is that it is configured to be moved from a shielding position for shielding the indoor gas flow path to an open position for opening the gas flow path.

  According to a second aspect of the present invention, in the first aspect, the filter is supported so as to be reciprocally tiltable in the direction of the gas flow path with the upper end portion as a center, and is always held at a shielding position suspended by a spring or its own weight. When the flow resistance of the oil mist-containing gas passing through the slit of the filter increases, the filter is tilted from the shielding position to the open position, and the gas is between the lower end edge of the filter and the bottom wall of the separation chamber. The gist is that a gap serving as a flow path is formed.

  According to a third aspect of the present invention, in the first or second aspect, the separation chamber is provided with oil mist separation plates at a plurality of locations so as to be located upstream of the filter, and each separation plate contains oil mist. The gist is that the gas is configured to meander in the separation chamber.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, a separation plate is erected on the bottom wall of the separation chamber so as to be positioned downstream of the filter. Is the gist.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, an upper edge of a leaf spring is attached to the upper wall of the separation chamber, and a filter is attached to the leaf spring. The gist of the invention is that the plate spring is elastically deformed and the filter is moved from the shield position to the open position when the flow resistance of the oil mist-containing gas passing through the slit of the filter increases.

Invention according to claim 6, Oite to claim 1, wherein the filter is a fixed filter having an opening wherein is disposed on the inner peripheral wall of the separation chamber, are disposed on the downstream side of the fixed filter the It is composed of a movable filter that can open and close the opening, and the movable filter is always held by a biasing member at a shielding position that closes the opening of the fixed filter.

(Function)
According to the present invention, when the flow resistance of the oil mist-containing gas passing through the slit of the filter increases, the filter is moved from the shielding position that shields the gas flow path to the open position that opens the gas flow path. For this reason, the pressure loss of oil mist containing gas is reduced.

  As described above, according to the present invention, it is possible to reduce the pressure loss of the oil mist-containing gas in the gas flow path.

1 is a longitudinal sectional view showing a first embodiment in which the present invention is embodied as an oil mist separator for engine blow-by gas. Sectional drawing in the 1-1 line | wire of FIG. The perspective view of a movable filter unit. The longitudinal cross-sectional view which shows the state which the filter of the oil mist separator displaced. (A) And (b) is a longitudinal cross-sectional view which shows 2nd Embodiment of the oil mist separator of this invention. (A) And (b) is a longitudinal cross-sectional view which shows 3rd Embodiment of the oil mist separator of this invention. (A) And (b) is a longitudinal cross-sectional view which shows 4th Embodiment of the oil mist separator of this invention. (A) is a plane sectional view showing an oil mist separator according to a fifth embodiment of the present invention, and (b) is a longitudinal sectional view. The perspective view of the principal part of 5th Embodiment. The longitudinal cross-sectional view which shows the conventional oil mist separator.

Hereinafter, a first embodiment of an oil mist separator embodying the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the oil mist separator 11 of this embodiment is disposed on a cylinder head cover 12 made of a synthetic resin of an engine. The housing 13 of the oil mist separator 11 is formed integrally with the cylinder head cover 12 and has a substantially square box shape. A gas inlet 14 communicating with the crank chamber of the engine is formed in the bottom wall 13a on one side of the housing 13. A gas outlet 15 communicating with the intake passage of the engine is formed in the upper wall 13b on the other side of the housing 13. Between the gas inlet 14 and the gas outlet 15, a gas flow path 16 of blow-by gas that is an oil mist-containing gas is formed in the housing 13. The gas flow path 16 functions as a separation chamber R that separates oil mist from blow-by gas.

  As shown in FIG. 1, a first separation plate 17 is integrally provided on the bottom wall 13 a of the housing 13 so as to be positioned in the vicinity of the gas inlet 14, and an upper end edge of the first separation plate 17. A first gap 18 is formed between the housing 13 and the upper wall 13b of the housing 13 for securing a gas flow path. A second separation plate 19 is integrally suspended from the upper wall 13 b of the housing 13 so as to be located downstream of the first separation plate 17, and a lower end edge of the second separation plate 19 and a bottom wall of the housing 13 are disposed. A second gap 20 for securing a gas flow path is formed between 13a and 13a. A third separation plate 21 is integrally provided on the bottom wall 13 a of the housing 13 so as to be positioned downstream of the second separation plate 19, and an upper end edge of the third separation plate 21 and the housing 13. A third gap 22 for securing a gas flow path is formed between the upper wall 13b and the upper wall 13b. A gas flow path 16 meandering in the separation chamber R is formed by the first to third separation plates 17, 19, 21 and the first to third gaps 18, 20, 22. Each of the upstream side surfaces of the first to third separation plates 17, 19, and 21 with respect to the gas flow path 16 adheres to and separates oil mist having a large particle size contained in blow-by gas. Separation surfaces 17a, 19a and 21a are formed. Small holes 17b and 21b that guide oil that has been captured and flowed down by the first and third separation surfaces 17a and 21a to the lower ends of the first and third separation plates 17 and 21 to the downstream side of the gas flow path 16. Are formed respectively.

A movable filter unit 25 for separating and capturing oil mist from blow-by gas is disposed in the gas flow path 16 in the housing 13 so as to be positioned downstream of the third separation plate 21. Yes. As shown in FIG. 2, the movable filter unit 25 includes a rotary shaft 26 supported on the left and right (upper and lower) side walls 13c and 13d of the housing 13, a sleeve 27 fixed to the rotary shaft 26, and the sleeve. As shown in FIG. 1, a filter 28 having an upper end portion fitted on the outer peripheral surface of 27 is formed. The filter 28 is formed of a nonwoven fabric made of an aggregate of fibers. As the fibers of the filter 28, for example, fine fibers having a straight shape, a smooth surface and a small frictional resistance, and fibers having high water repellency and oil repellency such as a fluororesin, such as inorganic fibers such as ceramics, are used. . It is preferable to perform a process of imparting oil drop sliding properties to the fibers of the filter 28. The average fiber diameter of the fibers of the filter 28 is set to 5 to 10 μm, for example, and the basis weight is set to 10 to 1000 g / m ² . With this configuration, the oil mist capturing performance of the filter 28 is enhanced, and oil (oil droplets) that has been captured and agglomerated easily flows down.

  As shown in FIG. 3, one end of a coil spring 29 is locked in a locking hole 26a formed at one end of the rotating shaft 26, and the other end of the coil spring 29 is connected as shown in FIG. The housing 13 is locked in a locking hole 13e formed in one side wall 13c. When the housing 13 is stopped by the coil spring 29 and when the flow rate of blow-by gas in the gas flow path 16 is low, the filter 28 is placed in the suspended position shown in FIG. The shield is held at the shielding position. Accordingly, in this state, blow-by gas passes through the slits between the fibers of the filter 28. Further, when the flow velocity of the blow-by gas in the gas flow path 16 increases, the flow resistance of the gas that permeates through the slits of the filter 28 increases, and the filter 28 is made elastic by the coil spring 29 around the rotating shaft 26. On the other hand, as shown in FIG. 4, it is rotated and tilted clockwise. A gap 31 is formed between the lower end edge of the filter 28 and the bottom wall 13 a of the housing 13 so as to be continuous with the gas flow path 16.

  An oil discharge port 30 is formed in the bottom wall 13 a of the housing 13 so as to be located downstream of the filter 28. Then, the oil separated by the filter 28 and flowing down to the upper surface of the bottom wall 13a is collected from the oil discharge port 30 into the cylinder head cover 12. The recovered oil is used to lubricate movable parts such as a cam shaft (not shown).

Next, the operation of the oil mist separator 11 configured as described above will be described.
When the engine is operated at a low speed, a low-speed blow-by gas generated by the operation is introduced into the housing 13 from the gas inlet 14 shown in FIG. Flows to the side. The blow-by gas that has flowed into the gas flow path 16 from the gas inlet 14 flows in a meandering manner through the first to third gaps 18, 20, and 22 by the action of the first to third separation plates 17, 19, and 21. In this process, the oil mist having a large particle size remaining in the blow-by gas is formed on the inner surface of the upper wall 13b of the housing 13 and the first to third separation surfaces 17a, 19a, and the first to third separation plates 17, 19, and 21. 21a etc. are attached and separated.

  The oil separated by the separation surfaces 17a, 19a, 21a of the first to third separation plates 17, 19, 21 is from small holes 17b, 21b formed at the lower ends of the first and third separation plates 17, 21. It flows downstream of the gas flow path 16 and is guided to the oil discharge port 30.

  Since the blow-by gas exiting the third gap 22 has a low speed, the flow resistance received by the filter 28 is small, and the filter 28 remains held at the shielding position. The oil mist having a small particle size contained in the blow-by gas is captured by the filter 28 while the filter 28 is held at the shielding position. In this case, since the filter 28 is composed of an aggregate of fibers, most of the oil mist having a small particle size contained in the blow-by gas is efficiently captured and aggregated by the slits of the filter 28 to form oil droplets. And flows down along the slit. Thereafter, the oil that has flowed down the slits of the filter 28 flows to the upper surface of the bottom wall 13 a of the housing 13 and is then discharged from the oil discharge port 30. The blow-by gas from which the oil mist has been separated is returned from the gas outlet 15 to the intake system of the engine.

  When the engine is operated at a high speed and the flow velocity of the blow-by gas flowing through the gas flow path 16 is increased, the flow resistance of the gas flowing through the slits of the filter 28 increases. In FIG. 1, the filter 28 is rotated clockwise around the rotation shaft 26 against the elastic force of the coil spring 29. As shown in FIG. 4, the lower end edge of the filter 28 and the housing A gap 31 is formed between the bottom wall 13a and the bottom wall 13a. For this reason, the resistance with respect to the gas which flows through the gas flow path 16 is reduced, and the pressure in the crank chamber can be prevented from rising. In this case, since the flow rate of blow-by gas is high, the oil separation efficiency at the first to third separation surfaces 17a, 19a, and 21a of the first to third separation plates 17, 19, and 21 is improved. Therefore, even if the gap 31 is formed, a high oil separation capability can be maintained as a whole oil mist separation device.

  Further, when the oil mist separator 11 is used for a long time and foreign matter such as carbon enters and holds in the narrow gap of the filter 28, the oil mist capturing function as a filter deteriorates. In this case, even if the flow velocity of the blow-by gas flowing through the gas flow path 16 is low, the flow resistance of the blow-by gas passing through the slits of the filter 28 increases, and the pressure of the gas against the filter 28 increases. Therefore, the filter 28 is tilted as shown in FIG. 4, and as a result, the pressure loss of the blow-by gas flowing through the gas flow path 16 is reduced.

Therefore, the oil mist separator 11 of the first embodiment has the following effects.
(1) In the first embodiment, as shown in FIGS. 1 and 2, the first to third separation plates 17, 19, and 21 are disposed in the separation chamber R of the housing 13, and the meandering gas flow path 16. Was formed. For this reason, the oil mist having a large particle size contained in the blow-by gas can be efficiently captured by the first to third separation surfaces 17a, 19a, and 21a of the first to third separation plates 17, 19, and 21, Oil mist separation efficiency can be improved.

  (2) As shown in FIGS. 1 and 2, the rotation shaft 26 of the filter 28 is rotatably supported on the side walls 13 c and 13 d of the housing 13, and the gas flow path 16 is always blocked by the coil spring 29. Hold the shield position. When the flow resistance of the blow-by gas flowing through the slits of the filter 28 is increased, the filter 28 is rotated clockwise around the rotation shaft 26 as shown in FIG. 4, and the lower end edge of the filter 28 and the housing 13 are rotated. A gap 31 serving as a gas flow path is formed between the bottom wall 13a and the bottom wall 13a. At this time, if the gap 31 having a slight width is formed, the pressure of the blow bikes in the gas flow path 16 is lowered, so that the oil mist separation efficiency is not so lowered. Moreover, at this time, the filter 28 forms a meandering flow path together with the first to third separation plates 17, 19, and 21, and the filter 28 is an oil mist collision surface in the same manner as the first to third separation plates 17, 19, and 21. As a separation function. As a result, the oil mist separator maintains a high oil separation capability. And since the excessive pressure rise of blow-by gas in the gas flow path 16 can be prevented, the pressure rise in the crank chamber of the engine can be prevented, and packing damage of the crank chamber can be prevented beforehand.

(Second Embodiment)
Next, a second embodiment of the oil mist separator embodying the present invention will be described with a focus on differences from the first embodiment.

  In the second embodiment, as shown in FIG. 5A, a separation plate 32 made of a solid body is connected to a sleeve 27 fitted to the rotary shaft 26, and the gas flow path 16 of the separation plate 32 is related. A filter 28 made of non-woven fabric is bonded to the upstream surface. The coil spring 29 is not used, and the separation plate 32 and the filter 28 are suspended by their own weight. When blow-by gas is supplied into the gas flow path 16, as shown in FIG. 5B, the separation plate 32 is inclined by the gas flow pressure, and the lower end edge of the filter 28 and the bottom wall of the housing 13. A gap 33 is formed between the gap 13a and the resistance against blow-by gas.

Therefore, the effect in the second embodiment is substantially the same as the effect described in the first embodiment.
(Third embodiment)
In the third embodiment, as shown in FIG. 6A, a variable attachment plate 34 made of a leaf spring is attached to the lower surface of the upper wall 13b of the housing 13, and the gas flow path 16 of the variable attachment plate 34 is related. A filter 28 made of non-woven fabric is bonded to the upstream surface. A fourth separation plate 35 is erected on the bottom wall 13a of the housing 13 so as to be located on the downstream side of the filter 28, and a small hole 35b through which oil passes is formed at the lower end of the fourth separation plate 35.

  In the third embodiment, the variable mounting plate 34 and the filter 28 are elastically deformed in an arc shape as shown in FIG. 6B in accordance with the flow velocity of the blow-by gas flowing in the gas flow path 16, and the filter A gap 31 is formed between the lower end edge of 28 and the bottom wall 13 a of the housing 13. The blow-by gas flowing downstream from the gap 31 collides with the fourth separation surface 35a of the fourth separation plate 35, and oil mist adheres to the fourth separation surface 35a and is separated. The separated oil is discharged to the oil discharge port 30 through a small hole 35 b formed at the lower end of the fourth separation plate 35.

Therefore, in the third embodiment, the oil mist contained in the blow-by gas can be effectively separated by the fourth separation surface 35a of the fourth separation plate 35.
(Fourth embodiment)
In the fourth embodiment, as shown in FIG. 7A, an oil mist separation plate 36 is provided on each of the bottom wall 13a and the upper wall 13b of the housing 13, and a gas flow path and A passage 36a is formed. A small hole 36b for allowing the oil separated by the separation plate 36 to pass therethrough is formed at the lower end of the separation plate 36 located on the lower side. A fixed filter 37 made of a pair of upper and lower nonwoven fabrics having L-shaped side surfaces is bonded to the bottom wall 13a and the upper wall 13b of the housing 13 and the downstream surface of the separation plate 36 with respect to the gas flow path 16.

  On the other hand, a support member 38 is fixed between the side walls 13c and 13d of the housing 13 so as to be positioned downstream of the fixed filter 37, and a coil is formed on the upstream surface of the gas flow path 16 of the support member 38. A movable filter 40 made of a nonwoven fabric urged toward the fixed filter 37 by a spring 39 is supported.

  In the fourth embodiment, when the blow-by gas flow is slow or the fixed filter 37 and the movable filter 40 are not clogged, the spring force of the coil spring 39 is shown in FIG. Thus, the movable filter 40 is in contact with the fixed filter 37. Accordingly, blow-by gas flowing in the gas flow path 16 passes through the slits of the fixed filter 37 and the movable filter 40, and oil mist is captured by the fixed filter 37 and the movable filter 40 between them. On the contrary, when the blow-by gas flow is fast or the fixed filter 37 and the movable filter 40 are clogged, the movable filter 40 resists the elastic force of the coil spring 39 by the flow pressure of the blow-by gas. Then, as shown in FIG. 7B, the gap 41 is formed between the fixed filter 37 and the movable filter 40 by being moved downstream. At this time, if the gap 41 having a slight width is formed, the pressure of the blow-by-case in the gas flow path 16 is lowered, so that the oil mist separation efficiency is not so lowered. Further, the fixed filter 37 and the movable filter 40 perform a separation function as a collision surface in addition to a capturing function as a filter, so that effective oil mist separation is performed.

(Fifth embodiment)
In the fifth embodiment, as shown in FIGS. 8 (a) and 8 (b), a gas filter as shown in FIG. 9 is used for the stationary filter 37 attached to the separation plate 36 of the fourth embodiment. The flow paths 37a are formed so as to be directed in the vertical direction and parallel to each other. The movable filter 42 that opens and closes the flow path 37 a is composed of a flexible frame 43 as a pair of front and rear urging members made of a square ring-shaped rubber or a leaf spring, and a nonwoven fabric 44 sandwiched between the frames 43. Configure. The flexible frame 43 at the upper end of the movable filter 42 is bonded to the upper surface of the fixed filter 37 with an adhesive 45 as shown in FIG.

  In the fifth embodiment, when the blow-by gas flow is at a low speed or the fixed filter 37 and the movable filter 42 are not clogged, as shown by solid lines in FIGS. 8A and 8B, The movable filter 42 is in contact with the fixed filter 37 by the elastic force of the flexible frame 43. Accordingly, blow-by gas flowing in the gas flow path 16 passes through the slits of the fixed filter 37 and the movable filter 42 (nonwoven fabric 44), and oil mist is captured by the fixed filter 37 and the nonwoven fabric 44 therebetween. Conversely, when the blow-by gas flow is at a high speed or the fixed filter 37 and the movable filter 42 are clogged, the movable filter 42 is centered on its upper edge due to the flow pressure of the blow-by gas. As indicated by a two-dot chain line in (a) and (b), it is elastically deformed downstream of the gas flow path, and the flow path 37a of the fixed filter 37 is opened. At this time, if the flow passage 37a is slightly opened, the blow-by-case pressure in the gas flow passage 16 is lowered, so that the oil mist separation efficiency is not so lowered. Further, the fixed filter 37 and the movable filter 42 perform a separation function as a collision surface in addition to a capturing function as a filter, and effective oil mist separation is performed.

  When the blow-by-case flow in the gas flow path 16 becomes low speed, the movable filter 42 is moved from the open position to the shielding position of the flow path 37 a of the fixed filter 37 by the elastic restoring force of the flexible frame 43.

(Example of change)
In addition, this embodiment can also be changed and embodied as follows.
In the embodiment shown in FIGS. 1 to 4, at least one of the first to third separation plates 17, 19, and 21 may be omitted.

The filter 28 of the movable filter unit 25 shown in FIG. 3 may be a plate shape made of a solid body having a large thickness.
-As a material of the said filter 28, you may use materials, such as a porous ceramic and a punching metal, for example.

  In the above-described embodiment, the oil mist separator provided in the cylinder head cover 12 of the engine is embodied. However, for example, it may be embodied as an oil mist separator that separates oil mist contained in the discharge gas of the compressor. .

  R ... separation chamber, 11 ... oil mist separator, 13 ... housing, 13a ... bottom wall, 13b ... top wall, 16 ... gas flow path, 28 ... filter, 31, 33 ... gap, 32 ... separation plate, 37 ... fixed filter 40, 42 ... movable filter, 43 ... flexible frame, 44 ... non-woven fabric.

Claims (6)

An oil mist-containing gas inlet hole is formed in the bottom wall of the separation chamber, a filter for separating the oil mist is disposed in the separation chamber, and an oil discharge hole is formed in the bottom wall of the separation chamber. In the provided oil mist separator,
When the flow resistance of the oil mist-containing gas when passing through the slit increases, the filter is moved from a shielding position that shields the gas flow path in the separation chamber to an open position that opens the gas flow path. An oil mist separator characterized by comprising. 2. The filter according to claim 1, wherein the filter is supported so as to be reciprocally tiltable in the direction of the gas flow path with the upper end portion as a center, and is always held at a shielding position suspended by a spring or its own weight, and passes through the slit of the filter. When the flow resistance of the oil mist-containing gas increases, the filter is tilted from the shielding position to the open position, and a gap serving as a gas flow path is formed between the lower end edge of the filter and the bottom wall of the separation chamber. An oil mist separator characterized by that. 3. The separation chamber according to claim 1, wherein the separation chamber is provided with oil mist separation plates at a plurality of locations so as to be located upstream of the filter, and the oil mist-containing gas meanders in the separation chamber by the separation plates. An oil mist separator characterized by being configured. The oil mist separator according to any one of claims 1 to 3, wherein a separation plate is erected on the bottom wall of the separation chamber so as to be positioned downstream of the filter. 5. The oil mist according to claim 1, wherein an upper end edge of a leaf spring is attached to the upper wall of the separation chamber, a filter is attached to the leaf spring, and the oil mist passes through a slit of the filter. The oil mist separator is configured such that when the flow resistance of the contained gas increases, the leaf spring is elastically deformed and the filter is moved from the shielding position to the open position. From Oite to claim 1, wherein the filter, the fixed filter is disposed on the inner peripheral wall of the separation chamber having an opening, opening and closing a movable filtering the opening is disposed on the downstream side of the fixed filter The oil filter is characterized in that the movable filter is always held by a biasing member at a shielding position for closing the opening of the fixed filter.

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