JP2009121281A - Oil separator for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent repeated inclusion of once-separated oil into blow-by gas and improve separation-recovery efficiency of the oil. <P>SOLUTION: A partition wall 16 is provided within a separator chamber 13 having a blow-by gas inflow port 14 and outflow port 15. Pores 19 are formed on the partition wall 16, and an oil separating mechanism 20 for secondary oil separation-capture treatment is formed by the pores 19 and a secondary collision plate 17. Oil drain pipes 22, 23 are arranged on bottom faces on upstream and downstream sides of the oil separating mechanism 20. A primary collision plate 25 having an irregular surface 25a for primary oil separation-capture treatment is provided in the position immediately near the downstream side of the blow-by gas inflow port 14, and gas passages 26 are set on both sides of the primary collision plate 25. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an oil separator for a blow bar gas passage provided in an internal combustion engine, particularly a cylinder head cover, and more particularly to an oil separator for positively separating and recovering oil mist contained in blow-by gas flowing through the blow bar gas passage. .

  In conventional internal combustion engines mounted on automobiles, blow-by gas that leaks into the crankcase from the clearance between the piston ring and the cylinder wall is returned to the intake system through the cylinder head and cylinder head cover, and sent to the combustion chamber along with the air-fuel mixture. Instead, it is configured to introduce fresh air. Such a system is called positive crankcase ventilation.

  In such a system, the oil mist contained in the blow-by gas is actively separated as oil so that the blow-by gas does not return to the intake system while containing the oil mist. -An oil separator is provided for recovery.

  As such an oil separator, for example, as described in Patent Document 1, after increasing the flow velocity of blow-by gas, this blow-by gas is collided with a wall body in the blow-by gas flow path, and the oil mist has the collision action. It is known that it is attached and separated and captured.

The separated oil is discharged (drained) to the outside through an oil drain port opened at the bottom of the oil separator.
JP 2002-106320 A (FIGS. 1 and 8)

  In the thing of FIG. 1 of patent document 1, after making the blowby gas which flowed in from the inflow pipe collide with the collision part of the unevenness | corrugation of the upper stage side, it guide | induces to the gas outlet, and also the unevenness | corrugation of the lower stage side from the gas outlet It collides with the collision part, and finally the oil flows out from the drain pipe at the bottom and the blow-by gas flows out from another outflow pipe, but until it collides with the bumpy collision part on the lower side The oil and blow-by gas once separated by the collision with the bumps and bumps on the upper side will both pass through the same narrow path, so the oil once separated is likely to be re-engaged in the blow-by gas, inevitably separating the oil・ Recovery efficiency is poor.

  Moreover, in the thing of FIG. 8 of patent document 1, after making the blow-by gas which passed the small ejection groove collide with the front collision board, it lets the communication path of the upper part of the collision board pass, and also the rear side The oil separated by the collision with the front collision plate accumulates at the base of the collision plate, so that the oil flows upstream of the blow-by gas passage through the ejection groove. Will flow back to the side. For this reason, once separated oil is easily entangled in the blow-by gas again, and the oil separation and recovery efficiency is poor as described above.

  The present invention has been made paying attention to such problems, and in particular, an oil separator that improves oil separation and recovery efficiency by preventing re-entrainment of once separated oil into blow-by gas. It is what.

  The invention according to claim 1 is an oil separator that is provided in a part of a blow-by gas passage oriented in the horizontal direction in the cylinder head cover and separates and collects mist-like oil contained in the blow-by gas. Assumption.

  In addition, a part of the blowby gas passage is formed, and a separator chamber whose longitudinal direction is directed to the flow direction of the blowby gas and an opening at one end in the longitudinal direction of the separator chamber are formed. A blow-by gas inlet that is oriented in the longitudinal direction of the separator chamber and whose cross-sectional area is smaller than the cross-sectional area of the separator chamber and larger in length than the diameter, and the longitudinal direction of the separator chamber A blow-by gas outlet opening formed at the other end of the separator, an oil separation mechanism that is provided at a central portion in the longitudinal direction of the separator chamber and separates oil mist contained in the blow-by gas as oil by at least a collision action; and Opened at the bottom on both sides of the oil separation mechanism in the separator chamber, the oil collected in the separator chamber An oil drain pipe that drops and discharges the gas to the outside, a collision plate formed in the separator chamber at a position near the blow-by gas inlet so as to be perpendicular to the blow-by gas inflow direction, and a collision plate in the separator chamber Gas passages formed by opening at least the lower half on both sides in the width direction of the gas, and the blow-by gas immediately after flowing into the separator chamber collides with the collision plate, It is made to flow in the downstream of the said collision board through the gas passage of the both sides of a board, It is characterized by the above-mentioned.

  In order to promote the separation of oil due to the collision with the collision plate and the downward flow of the oil, and to reliably prevent the oil from re-entraining when blow-by gas passes through the gas passages on both sides of the collision plate, As described in Item 2, the collision surface of the collision plate with the blow-by gas is formed as an uneven surface shape in which the axis of the concave portion and the convex portion is directed in the vertical direction, and the gas passage includes: It is desirable that both sides in the width direction of the collision plate are formed to be open over the entire height of the separator chamber.

  Further, as a more specific structure of the oil separation mechanism, for example, as defined in claim 3, pores are formed in a partition wall provided in the casing, and blow-by gas passing through the pores is supplied to the partition wall. It is assumed that the oil mist is separated and captured by colliding with a collision plate that is close to the bottom and opened on the lower side.

  In this case, as described in claim 4, it is desirable that a plurality of pores be formed in the partition wall forming the oil separation mechanism.

  Therefore, in at least the first aspect of the invention, primary oil separation is achieved by the blow-by gas immediately after flowing in from the blow-by gas inlet in the separator chamber colliding with a collision plate adjacent to the blow-by gas inlet. Will be. Further, the blow-by gas from which the primary oil separation has been performed passes through an oil separation mechanism at a later stage to be subjected to secondary oil separation.

  In this case, the blow-by gas that has undergone primary oil separation and the oil after separation flow downstream through the gas passages formed on both sides of the collision plate, but after separation with a large specific gravity. The oil travels along the bottom of the separator chamber and is collected in the oil drain pipe in the subsequent stage, while the blow-by gas that has undergone primary oil separation passes through the upper space in the separator chamber, so that the oil that has been once separated is not involved. To the oil separation mechanism.

  According to the first aspect of the invention, the blow-by gas immediately after flowing into the separator chamber collides with the collision plate to perform primary oil separation, and the blow-by gas after the primary oil separation collides with the oil. Since it is made to flow to the downstream side of the collision plate through the gas passage formed in the lower half of both sides of the plate, it is possible to prevent re-entrainment of oil into the blow-by gas after primary oil separation. Therefore, the oil separation / recovery efficiency is improved as compared with the conventional structure.

  Further, according to the invention described in claim 2, since the collision surface of the collision plate has an irregular surface shape, it is possible to promote the downward flow of the oil separated and collected by the collision. In addition, since both sides of the collision plate are gas passages that are completely open in the vertical direction, even if the blow-by gas and oil after the primary oil separation pass together, the oil to the blow-by gas is restored. Entrainment can be reliably prevented.

  1 and 2 show a more specific embodiment of an oil separator according to the present invention, FIG. 1 shows a schematic cross-sectional structure of an engine 1 as an internal combustion engine, and FIG. 2 (A) shows a cylinder head cover 5 of FIG. (B) of the same figure shows the horizontal sectional view of oil separator 11 of the figure (A).

  As shown in FIG. 1, the engine 1 includes an oil pan 2, a cylinder block 3, a cylinder head 4, a cylinder head cover (rocker cover) 5, and the like as is well known, and a crankshaft 7 accommodated in a crankcase 6. The piston 8 is reciprocally driven. In the example of FIG. 1, the crankcase 6 communicates with the inside of the cylinder head cover 5 through the internal space of the cylinder head 4, and the cylinder head cover 5 has a fresh air inlet 10 in addition to the PCV control valve 9. It is attached.

  For example, when the engine 1 is under a low load, the internal pressure of the engine 1 becomes negative due to the action of the PCV control valve 9, and fresh air is introduced from the air cleaner side (not shown) into the crankcase 6 via the fresh air inlet 10 and the cylinder head cover 5. On the other hand, the blow-by gas G is mixed with fresh air in the crankcase 6 and is guided to the intake manifold side through the inside of the cylinder head cover 5 and the PCV control valve 9. When the load is high, the blow-by gas G is also discharged from the fresh air inlet 10 and is introduced into the intake manifold via an intake duct (not shown).

  Here, an oil separator 11 for separating and collecting the oil contained in the blow-by gas G is provided in a part of the blow-by gas passage in the cylinder head cover 5, and the details thereof are shown in FIG.

  As shown in FIGS. 2A and 2B, for example, a separator that is a main element of the oil separator 11 can be obtained by mounting a resin inner cover 12 inside a part of the resin cylinder head cover 5. A chamber 13, that is, a separator chamber 13 that functions as a part of the blow-by gas passage is formed in isolation. Here, since the flow of the blow-by gas G is set in the horizontal direction in the cylinder head cover 5, the longitudinal direction of the separator chamber 13 coincides with the direction of the flow of the blow-by gas G. And having a rectangular cross-sectional shape.

  A blow-by gas inlet 14 is provided at one end in the longitudinal direction of the separator chamber 13, and a blow-by gas outlet 15 is provided at the other end in the longitudinal direction of the separator chamber 13, that is, as far as possible from the blow-by gas inlet 14. The blow-by gas inlet 14 is formed on the upstream side of the blow-by gas inlet 14 with an opening 14a, and the blow-by gas outlet 15 is opened to the intake manifold side via the PCV control valve 9 of FIG. Connected.

  The blow-by gas inlet 14 has a cross-sectional area that is significantly smaller than the cross-sectional area of the separator chamber 13 in order to increase the flow velocity of the blow-by gas G flowing into the separator chamber 13, and as described above, Even if the cylinder head 4 has an opening 14a having a size as large as that of the blower gas inlet 14 itself at a position closest to the separator chamber 13, the length is larger than the diameter of the blow-by gas inlet 14 itself. It is formed as.

  The blow-by gas inlet 14 is formed in an opening near the inner cover 12 that functions as the bottom surface of the separator chamber 13, while the blow-by gas outlet 15 is a portion near the upper wall surface or the upper wall surface of the separator chamber 13, That is, the opening is formed at a position higher than the blow-by gas inlet 14.

  A partition wall 16 is provided in the central portion of the separator chamber 13 in the longitudinal direction so as to partition the internal space that will function as a part of the blow-by gas passage into an upstream chamber R1 and a downstream chamber R2. Further, a secondary collision plate 17 is provided on the downstream side of the partition wall 16 at a predetermined distance from the partition wall 16. However, at the lower end of the secondary collision plate 17, all or part of the width direction is opened as a passage 18 that becomes a part of the blow-by gas passage. In the partition wall 16, a plurality of pores 19 are provided in a horizontal series at the center in the height direction, and an opening on the downstream side of each of the pores 19 is a passage in the secondary collision plate 17 adjacent to the partition wall 16. It faces the part other than 18. Therefore, the oil separation mechanism 20 is formed by the pores 19 formed in the partition wall 16 and the secondary collision plate 17.

  Here, a passage 21 similar to the passage 18 on the side of the secondary collision plate 17 is formed at the lower end of the partition wall 16 so that oil or the like can flow between the upstream side and the downstream side of the partition wall 16 as will be described later. However, in the present embodiment, the passage 21 at the lower end of the partition wall 16 is not necessarily essential.

  On the both sides of the inner cover 12 that functions as the bottom surface of the separator chamber 13 with the oil separation mechanism 20 interposed therebetween, oil drain pipes 22 or 23 having a tapered lower end portion are formed protruding downward. These oil drain pipes 22, 23 open to the separator chamber 13 with a circular opening at the upper end portion, and open into the cylinder head 4 at the lower end portion with an oval opening 24 having a smaller area than the upper end portion. ing.

  Further, a primary collision plate 25 is provided in the separator chamber 13 on the downstream side of the opening position of the blow-by gas inlet 14 and in the immediate vicinity thereof. The primary impingement plate 25 is set so as to be perpendicular to the axis of the blow-by gas inlet 14 and thus to the inflow direction of the blow-by gas from the blow-by gas inlet 14, and from the bottom side of the separator chamber 13. Similarly, although it is erected so as to straddle the upper wall surface side of the separator chamber 13, it is opened as gas passages 26 on both sides in the width direction of the primary collision plate 25. That is, at the both sides in the width direction of the primary collision plate 25, the same is opened from the bottom surface side of the separator chamber 13 to the upper wall surface side of the separator chamber 13, thereby communicating the upstream side and the downstream side of the primary collision plate 25. A gas passage 26 is formed.

  In addition, one surface of the primary collision plate 25 that faces the opening of the blow-by gas inlet 14, that is, one surface that blow-by gas that has flowed in from the blow-by gas inlet 14 collides is defined as an uneven surface 25 a. Here, on one surface of the primary collision plate 25, a plurality of convex portions and concave portions whose axis is directed in the vertical direction are formed alternately and at equal pitches in the plate width direction. As the uneven surface 25a. In this way, the collision surface of the blow-by gas G against the primary collision plate 25 is an uneven surface 25, which contributes to an increase in the contact area or the collision area with the blow-by gas G containing oil mist, as will be described later. It serves to promote the rapid flow of oil separated by collision.

  Here, if the flow rate of the blow-by gas G at the blow-by gas inlet 14 is about 5 to 15 m / sec, for example, the distance a between the opening on the separator chamber 13 side of the blow-by gas inlet 14 and the primary collision plate 25 a Is preferably set to about 5 mm. Further, as the secondary collision plate 17 forming the oil separation mechanism 20, the primary collision plate 25 having the same uneven surface shape may be adopted.

  Further, the partition wall 16, the secondary collision plate 17, and the primary collision plate 25 are previously formed integrally with the inner cover 12, and the inner cover 12 is set inside the cylinder head cover 5 and integrated by fusion or the like. In this case, the separator chamber 13 is separated and formed, and at the same time, the partition wall 16, the secondary collision plate 17, and the primary collision plate 25 are positioned at predetermined positions in the separator chamber 13.

  Therefore, according to the oil separator 11 configured in this way, the blowby gas G in the crankcase 6 of FIG. 1 passes through the passage 6a and then passes from the opening 14a of FIG. 2A to the blowby gas inlet 14. Inflow. The blow-by gas G that has flowed into the blow-by gas inlet 14 is accelerated because its passage area is small, and collides with the primary collision plate 25 from the direction perpendicular to the surface in a state where the flow velocity is increased. Due to the collision, oil mist contained in the blow-by gas G adheres to the uneven surface 25a of the primary collision plate 25, and primary oil separation / capture processing is performed. The blow-by gas G whose direction is changed by the collision with the primary collision plate 25 passes through the gas passages 26 on both sides of the primary collision plate 25 and flows into the chamber R1 side.

  Here, the oil separated and captured by the collision with the primary collision plate 25 flows down the uneven surface 25a, accumulates on the inner cover 12 which is the bottom surface, and eventually flows into the chamber R1 side through the gas passage 26. The oil is collected in the oil drain pipe 22 and finally dropped and discharged into the space of the cylinder head 4.

  In this case, the blow-by gas G that has been subjected to the primary oil separation / capture process and the oil that has been separated / captured by the primary collision plate 25 eventually pass through the same gas passage 26 and are then on the chamber R1 side. However, since the oil having a large specific gravity only moves on the bottom surface in the gas passage 26, the oil is not entangled in the blow-by gas G again.

  In the example of FIG. 2, the gas passages 26 on both sides of the primary collision plate 25 are opened at the total height of the separator chamber 13. However, in order to achieve the intended purpose, the gas passage 26 has a total height of the separator chamber 13. Of these, at least the lower half should be open.

  The flow rate of the blow-by gas G flowing into the downstream side of the primary collision plate 25 in the chamber R1 is increased again when passing through the pores 19 formed in the partition wall 16 forming the oil separation mechanism 20, The oil collides with the adjacent secondary collision plate 17 while the flow velocity is increased, and secondary oil separation / capture processing is performed on the same principle as that of the previous primary collision. That is, by the secondary collision of the blow-by gas G against the secondary collision plate 17, the oil mist contained in the blow-by gas G adheres to the secondary collision plate 17 and is separated and captured. The blow-by gas G whose direction has been changed by the collision passes through the passage 18 below the secondary collision plate 17 and flows into the downstream chamber R2, and finally flows out from the blow-by gas outlet 15.

  Then, the oil separated and captured by the collision with the secondary collision plate 17 travels down the secondary collision plate 17 and accumulates on the inner cover 12 as the bottom surface, and eventually passes through the opening 18 and becomes a downstream chamber. After flowing into the R2 side, it is collected by the oil drain pipe 23.

  Even in this case, the blow-by gas G that has been subjected to the secondary oil separation / capture processing and the oil that has been separated / captured by the secondary collision plate 17 eventually pass through the same gas passage 18 together. Although flowing into the chamber R2 side, since the area of the passage 18 is relatively large, the oil having a large specific gravity only moves on the bottom surface in the passage 18, and the oil again flows into the blow-by gas G. There is no such thing as getting caught up.

  Here, when the passage 21 is formed at the lower end of the partition wall 16 as shown in FIG. 2A, even if the oil is not sufficiently collected in the oil drain pipe 22 on the upstream side, It is possible to flow into the downstream chamber R <b> 2 through the bottom surface of the passage 21, and finally the oil that has not been collected by the upstream oil drain pipe 22 is also collected by the downstream oil drain pipe 23. It becomes possible to do.

  As described above, according to the present embodiment, it is assumed that the primary separation / capture processing of oil due to the primary collision and the secondary separation / capture processing of oil due to the secondary collision are repeated. Since the re-entrainment of the oil into the blow-by gas G can be prevented in advance, the oil separation / recovery efficiency is dramatically improved.

  3 and 4 show a second embodiment of the oil separator 11 according to the present invention, and the same reference numerals are given to the parts common to the first embodiment.

  This second embodiment is shown in FIG. 1 in that the blow-by gas inlet 14 of the oil separator 11 opens directly to the crankcase 6 via the passage 6b without passing through the internal space of the cylinder head 4. Unlike the first embodiment, the internal structure of the separator chamber 13 shown in FIG. 4 is basically the same as that shown in FIG.

  Therefore, the same effect as that of the first embodiment can be obtained in the second embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the 1st Embodiment of this invention, and is a schematic cross-section explanatory drawing of the engine provided with the oil separator. It is a figure which shows the detail of the oil separator incorporated in the cylinder head cover of FIG. 1, (A) is the vertical sectional view, (B) is the horizontal sectional view of the same figure (A). It is a figure which shows the 2nd Embodiment of this invention, and is a schematic cross-section explanatory drawing of the engine provided with the oil separator. It is a figure which shows the detail of the oil separator incorporated in the cylinder head cover of FIG. 3, (A) is the vertical sectional view, (B) is the horizontal sectional view of the same figure (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 ... Cylinder head cover 11 ... Oil separator 13 ... Separator chamber 14 ... Blow-by gas inflow port 15 ... Blow-by gas outflow port 16 ... Partition 17 ... Secondary collision plate 19 ... Pore 20 ... Oil separation mechanism 22, 23 ... Oil drain pipe 25 ... Primary collision plate 25a ... Uneven surface 26 ... Gas passage G ... Blow-by gas R1 ... Upstream chamber R2 ... Downstream chamber

Claims (4)

An oil separator that is provided in a part of a blow-by gas passage directed horizontally in the cylinder head cover and separates and collects mist-like oil contained in the blow-by gas,
A separator chamber that forms part of the blowby gas passage and whose longitudinal direction is directed in the flow direction of the blowby gas;
An opening is formed at one end in the longitudinal direction of the separator chamber, and the cross-sectional area of the separator chamber is smaller than the cross-sectional area of the separator chamber and is longer than the diameter. A blow-by gas inlet;
A blow-by gas outlet formed in the other end in the longitudinal direction of the separator chamber;
An oil separation mechanism that is provided in a central portion in the longitudinal direction of the separator chamber and separates oil mist contained in blow-by gas as oil by at least a collision action;
An oil drain pipe that opens to the bottom of both sides of the oil separation mechanism in the separator chamber and drops and discharges the oil accumulated in the separator chamber to the outside;
A collision plate formed in the separator chamber so as to be perpendicular to the blow-by gas inflow direction at a position closest to the blow-by gas inlet;
A gas passage formed by opening at least the lower half of the collision plate in both sides of the collision plate in the width direction;
With
An internal combustion engine characterized in that blow-by gas immediately after flowing into the separator chamber collides with a collision plate and then flows to the downstream side of the collision plate through gas passages on both sides of the collision plate. Engine oil separator. Of the collision plate, the collision surface with blow-by gas is formed as a concave-convex surface shape in which the axis of the concave and convex portions is directed in the vertical direction,
2. The oil separator for an internal combustion engine according to claim 1, wherein the gas passage is formed such that both sides in the width direction of the collision plate are opened over the entire height of the separator chamber.   The oil separation mechanism forms pores in a partition wall provided in the casing, and blow-by gas that has passed through the pores collides with a collision plate that is close to the partition wall and is open on the lower side to separate oil mist. The oil mist separator for an internal combustion engine according to claim 1 or 2, wherein the oil mist separator is captured.   4. The oil mist separator for an internal combustion engine according to claim 3, wherein a plurality of pores are formed in the partition wall forming the oil separation mechanism.

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