JP2015158132A - Internal combustion engine oil separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize both the capture performance and pressure loss of an oil separator at high level.SOLUTION: An oil separator 1 provided in a cylinder head cover of an internal combustion engine includes a partition wall 27 that is provided between a blow-by gas inlet 24 and a blow-by gas outlet 25 and that is penetrated by a plurality of passage holes 30, and blow-by gas transformed into a high-speed blow-by gas flow in the passage holes 30 collides against an adjacent collision plate 32. A slit opening portion 33 is formed between a lower end 32a of the collision plate 32 and a bottom surface of a separator chamber 23, and separated oil is discharged through a drain pipe 35. The collision plate 32 includes a fiber material layer 41 that serves as a front surface opposed to the passage holes 30; and a mesh member 42 that serves as a rear surface and that supports this fiber material layer 41. Most of the high-speed blow-by gas flow exiting the passage holes 30 passes through the fiber material layer 41 and the mesh member 42, so that pressure loss can be reduced.

Description

  The present invention relates to an improvement in an oil separator that is provided in a cylinder head cover of an internal combustion engine and separates oil mist from blow-by gas taken out through the cylinder head cover.

  For example, in an internal combustion engine for automobiles, as is well known, blow-by gas containing unburned components leaked from the combustion chamber into the crankcase is introduced into the engine intake system together with fresh air taken from outside and burned. ing. And since the blow-by gas that has passed through the crankcase contains oil mist, in order to prevent the oil from being taken away into the engine intake system, as disclosed in Patent Documents 1 and 2, An oil separator is provided in a part of the cylinder head cover, and the blow-by gas is taken out after separating and removing the oil through the oil separator. In general, two blow-by gas passages are connected to the cylinder head cover, and fresh air is introduced from one passage under normal operating conditions. However, blow-by gas passes through both passages under high load conditions. Since it flows, an oil separator is provided for each of the cylinder head covers.

  The oil separators of Patent Documents 1 and 2 are so-called inertial collision type oil separators, and a partition wall provided with a large number of passage holes is disposed in the oil separator chamber, and is opposed to the passage holes adjacent to the partition walls. The collision plate is arranged, and the blow-by gas containing oil mist passes through the passage hole of the partition wall to increase the flow velocity, and when it exits the passage hole and collides with the collision plate at high speed, the oil mist Adheres to the collision plate and is collected. A slit-like opening is provided at the lower end of the collision plate, and the oil that has been separated by the collision plate and has grown into large droplets flows downstream through the opening to the bottom of the oil separator chamber. Is dropped from the lower end discharge port of the drain pipe provided in the valve chamber.

  In Patent Document 3, a filter made of a block-like fiber assembly is provided in the separator chamber instead of the partition wall having a large number of passage holes, and a fiber assembly is formed on the surface of the separation plate facing the filter. An oil separator having an auxiliary filter made of is attached. In this case, the oil mist is basically removed by filtering when blow-by gas passes through the filter, and further, the blow-by gas that has passed through the filter collides with the separator and flows in a meandering manner. Removal is performed.

JP 2005-120855 A JP 2009-121281 A JP 2010-248935 A

  In the inertial collision type oil separator as in Patent Documents 1 and 2, in order to further improve the oil mist capturing performance, it is necessary to form a narrow passage hole and increase the gas flow rate of blow-by gas ejected from the passage hole. is necessary.

  However, when the passage cross-sectional area of the passage hole is reduced in this way, the pressure loss before and after the partition wall is increased accordingly. Therefore, there is a problem that the pressure loss causes the pressure in the oil separator chamber on the downstream side of the partition wall to be low, and the oil easily flows back from the valve operating chamber side through the drain pipe.

  That is, with the conventional configuration, it is impossible to achieve both a sufficient level of oil mist capturing performance and pressure loss in the oil separator, which are in a trade-off relationship with each other.

  In addition, the method using filtering using a filter made of a fiber aggregate as in Patent Document 3 is not preferable because the pressure loss is further increased as compared with an inertial collision type oil separator.

  The present invention is an oil separator that is provided in a cylinder head cover of an internal combustion engine and separates oil mist from blow-by gas taken out through the cylinder head cover. The oil separator has a blow-by gas inlet at one end and a blow-by gas at the other end. A separator chamber having an outlet, a partition wall provided to partition the separator chamber into an inlet chamber on the blow-by gas inlet side and an outlet chamber on the blow-by gas outlet side, and having a plurality of passage holes formed therethrough, and A collision plate provided in the outlet chamber adjacent to the partition wall so as to face the passage hole, and a lower end of the collision plate and a bottom surface of the separator chamber over a part or all of the width of the collision plate. An opening provided in the form of a slit in between and the separated oil is discharged from the bottom surface of the separator chamber into the valve chamber of the internal combustion engine. It includes a drain portion that, the. And the said collision board is comprised from the fiber material layer of the surface facing the said channel | path hole, and the net-like member of the back surface side which supports this fiber material layer.

  In a preferred embodiment, the fiber material layer is composed of a nonwoven fabric.

  In the oil separator configured as described above, blow-by gas flows through the separator chamber due to a pressure difference between the pressure on the blow-by gas inlet side and the pressure on the blow-by gas outlet side. The flow rate of the blow-by gas is increased by passing through the plurality of passage holes in the partition wall, and oil mist adheres to the collision plate and is recovered when it exits the passage hole and collides with the collision plate at high speed. The oil that has been separated by the collision plate and has grown into large droplets drops from the lower end of the collision plate and is discharged into the valve chamber through the drain portion on the bottom surface of the separator chamber.

  Here, in the present invention, the collision plate is composed of a fiber material layer and a mesh member. Therefore, at least a part of the high-speed gas flow that has passed through the passage hole of the partition wall flows through the collision plate. . That is, in the downstream of the partition wall, a part of the gas flow passes through the opening between the bottom of the collision plate and the bottom surface of the separator chamber in the same manner as the conventional oil separator, and a part of the gas flow The pressure loss as an oil separator is reduced accordingly.

  Further, since the oil mist in the blow-by gas is effectively separated by the fiber material layer, it is possible to obtain high oil mist capturing performance.

  According to this invention, the collision plate facing the passage hole of the partition wall is composed of the fiber material layer and the mesh member, so that both the oil mist capturing performance and the oil separator pressure loss can be achieved at a higher level. Can do.

1 is a schematic cross-sectional view of an internal combustion engine provided with an oil separator according to the present invention. Sectional drawing which shows one Example of an oil separator. Sectional drawing along the AA line of FIG. The front view of the partition provided with the passage hole. The front view which shows one Example of a mesh member. A first comparative example (a) in which the collision plate is composed only of a plate-like member, a second comparative example (b) having a fiber material layer on the surface of the plate-like member, and an example (c) of the present invention. Explanatory drawing which contrasted and showed the basic composition and the flow of gas and oil mist. The characteristic view which showed the pressure loss of the oil separator by contrasting with the 1st, 2nd comparative example, and an Example. The characteristic view which showed the oil mist capture | acquisition performance of the oil separator by contrasting with the 1st, 2nd comparative example, and an Example. The characteristic view which showed the relationship between the oil mist capture | acquisition performance and a pressure loss in contrast with the 1st, 2nd comparative example and the Example.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 schematically shows the configuration of an internal combustion engine provided with an oil separator 1 according to the present invention. A crankcase 4 is defined by a cylinder block 2 and an oil pan 3. And the valve operating chamber 6 in the cylinder head 5 communicate with each other. A cylinder head cover 7 forming a part of the blow-by gas processing device includes a fresh air inlet 8 connected to a throttle valve upstream side (for example, an air cleaner) of an intake system (not shown), and a throttle valve downstream side (for example, an intake manifold). And a blow-by gas take-out port 9 connected to a), and the blow-by gas take-out port 9 is provided with a known PCV valve 10 for controlling the flow rate of the blow-by gas in accordance with the pressure difference.

  In such a configuration, fresh air is introduced from the fresh air introduction port 8 due to the pressure difference between the throttle valve and the throttle valve, and the crankcase 4 and the valve operating chamber 6 are ventilated. The blow-by gas in the crankcase 4 and the valve operating chamber 6 is introduced to the downstream side of the throttle valve through the PCV valve 10 at the blow-by gas outlet 9 together with the fresh air.

  And in order to remove the oil mist mixed in this blow-by gas, the oil separator 1 is integrally provided inside the cylinder head cover 7 provided with the blow-by gas outlet 9.

  The arrows in FIG. 1 indicate the gas flow when the internal combustion engine is at low and medium loads. However, when the throttle valve is close to full open, a part of the blow-by gas flows from the fresh air inlet 8. Is also discharged into the intake system. Accordingly, a similar oil separator is generally provided also on the fresh air inlet 8 side, and the oil separator 1 of the present invention is an oil separator on the blow-by gas outlet 9 side or an oil on the fresh air inlet 8 side. It can be applied to any separator.

  2 and 3 show the oil separator 1 integrated with the cylinder head cover 7 as described above as a single unit. The oil separator 1 is formed on the ceiling surface of the cylinder head cover 7 as a part of the synthetic resin cylinder head cover 7 and covers the lower surface opening of the housing part 21 as a part of the synthetic resin cylinder head cover 7. In this manner, the synthetic resin separator cover 22 is attached to the cylinder head cover 7. In addition, this invention is not limited to this, It can also be set as the structure provided with the independent housing part 21 shape | molded separately from the cylinder head cover 7. FIG.

  The oil separator 1 elongates along, for example, a direction perpendicular to the cylinder row (the engine width direction), and an elongated separator chamber 23 having a rectangular cross section is defined between the housing portion 21 and the separator cover 22. It is made. The blow-by gas inlet 24 is located at one end of the separator chamber 23 in the longitudinal direction, and the blow-by gas outlet 25 is located at the other end. Therefore, the blow-by gas basically passes through the separator chamber 23. It flows linearly along the longitudinal direction.

  The blow-by gas inlet 24 includes a rectangular opening formed in the separator cover 22. In other words, in this embodiment, the blow-by gas inlet 24 opens to the bottom surface of the separator chamber 23, and the separator chamber 23 communicates with the valve operating chamber 6 through the blow-by gas inlet 24. Further, in this embodiment, the blow-by gas outlet 25 is disposed on the upper surface of the housing portion 21, in other words, provided so as to penetrate the ceiling wall of the cylinder head cover 7. As described above, when the oil separator 1 is provided on the blow-by gas outlet 9 side, the blow-by gas outlet 25 becomes the blow-by gas outlet 9, and a PCV valve (not shown) is attached. The blow-by gas outlet 25 may be disposed on the end surface (relatively upper position) of the elongated separator chamber 23.

  A plate-like partition wall 27 orthogonal to the longitudinal direction of the separator chamber 23 is provided in the middle portion of the separator chamber 23 in the longitudinal direction, and the partition chamber 27 allows the separator chamber 23 to be on the blow-by gas inlet 24 side. It is divided into an inlet chamber 28 and an outlet chamber 29 on the blow-by gas outlet 25 side. In the illustrated example, the partition wall 27 is formed integrally with the separator cover 22 and extends upward to a height that reaches the ceiling surface of the housing portion 21. On the contrary, the partition wall 27 may be formed integrally with the housing portion 21, that is, the cylinder head cover 7. The partition wall 27 has a plurality of passage holes 30 serving as throttles for increasing the flow rate of blow-by gas.

  As shown in FIG. 4, the partition wall 27 has a rectangular shape which is long in the right and left in this embodiment, and a total of 14 passages are arranged on the partition wall 27 in three rows of an upper stage, a middle stage and a lower stage. A hole 30 is disposed. These fourteen passage holes 30 are arranged so as to be offset upward as a whole in the rectangular partition wall 27, and the communication hole 30 does not exist in the lower part of the partition wall 27. Each passage hole 30 is formed as a hole having a circular cross section. The diameter of each passage hole 30 is set so that a desired flow velocity (for example, 5 m / sec or more) necessary for separating oil mist in blow-by gas can be obtained. In order to make the oil mist go straight with sufficient inertia, it is desirable that the passage length of the passage hole 30 (that is, the thickness of the partition wall 27) is twice or more the diameter of the passage hole 30. In the present invention, the passage hole 30 does not necessarily have a circular cross section, and may have a rectangular cross section or a triangular cross section.

  In the outlet chamber 29, a collision plate 32 is disposed adjacent to the partition wall 27 and parallel to the partition wall 27. The collision plate 32 faces the passage hole 30 with an appropriate interval so as to separate the oil mist from the blow-by gas flowing at high speed through the communication hole 30. As will be described later, the collision plate 32 is composed of a fiber material layer 41 on the front surface facing the passage hole 30 and a mesh member 42 on the back surface side that supports the fiber material layer 41.

  The collision plate 32 extends downward from the ceiling surface of the housing portion 21 to a predetermined height position, and an opening 33 that opens in a slit shape between the lower end 32a of the collision plate 32 and the bottom surface of the separator chamber 23. Is provided. The vertical dimension of the collision plate 32 corresponds to the positions of the plurality of communication holes 30 arranged in the partition wall 27, that is, the high-speed gas flow that has passed through each communication hole 30 collides with the collision plate 32. In addition, the position of the lower end 32a is set.

  The oil separated from the blow-by gas in the collision plate 32 flows down from the lower end 32 a and flows downstream along the bottom surface of the separator chamber 23 through the opening 33.

  A drain pipe 35 is integrally formed with the separator cover 22 on the bottom surface of the outlet chamber 29 as a drain portion for discharging collected oil to the valve operating chamber 6 side. The drain pipe 35 extends downward in a cylindrical shape toward the valve operating chamber 6 and has a small discharge port at the lower end.

  In the oil separator 1 configured as described above, the blow-by gas flowing in the separator chamber 23 from the blow-by gas inlet 24 to the blow-by gas outlet 25 is reduced in the passage area by the passage hole 30 penetrating the partition wall 27. It becomes a high-speed flow and collides with the collision plate 32. Therefore, the oil mist contained in the blow-by gas is separated and adheres to the collision plate 32. The oil mist trapped in this way gradually grows into large droplets, drops from the lower end 32a of the collision plate 32 to the bottom surface of the separator chamber 23, and flows downstream on this bottom surface. Finally, it is dropped from the drain pipe 35 to the valve operating chamber 6. In the drain pipe 35, liquid oil accumulates to a certain height, so that the blow-by gas from the discharge port at the lower end of the drain pipe 35 (that is, blow-by gas from the valve operating chamber 6 (see FIG. 1) to the outlet chamber 29). Inflow) is prevented.

  Here, the greater the pressure loss due to the passage resistance of each part of the oil separator 1, the greater the pressure difference between the inlet chamber 28 and the outlet chamber 29 and hence the pressure difference between the valve chamber 6 and the outlet chamber 29. The blow-by gas backflow through the drain pipe 35 is likely to occur. When this reverse flow of blow-by gas occurs, oil scatters from the drain pipe 35 into the outlet chamber 29 and is taken out to the blow-by gas outlet 9. On the other hand, if the diameter of the passage hole 30 is set to be large in order to reduce the pressure loss, the pressure loss is reduced, but the flow rate of the blow-by gas exiting from each passage hole 30 is lowered, so that the oil mist capturing performance is lowered. To do.

  In the present invention, in order to realize a reduction in pressure loss while ensuring oil mist capturing performance, a collision plate 32 facing the passage hole 30 is provided with a fiber material layer 41 on the surface facing the passage hole 30 and the fiber material. And a net-like member 42 on the back surface side that supports the layer 41 and has air permeability as a whole. As the fiber material layer 41, for example, non-woven fabric is used in the above-described embodiments, but in addition, fabrics such as fleece, and various forms such as fibers formed into a plate with a binder are used. Is possible. That is, any form may be used as long as the fine flow path can be configured so that the oil mist can be separated and removed while having sufficient air permeability.

  Further, as the mesh member 42, for example, as shown in FIG. 5, a large number of rhombus meshes are formed by forming a large number of slits in a metal plate and extending the slits in a direction perpendicular to the slits. So-called expanded metal is used. In addition to this, various forms such as a general wire mesh knitted wire, a so-called punching metal in which a large number of small holes are formed in a metal plate, a lattice plate or a perforated plate made of a synthetic resin can be used. . When the mesh member 42 is made of synthetic resin, it can be molded integrally with the housing portion 21 and the separator cover 22. In the illustrated example, a fiber material layer 41 made of non-woven fabric is adhered to the surface of a net-like member 42 made of expanded metal by means such as adhesion or welding, and the net-like member 42 is attached to the housing part 21 or the separator cover 22. It is attached by appropriate means (for example, holding by a ditch or a locking claw, a screw, etc.). The metal mesh member 42 may be inserted when molding the synthetic resin housing 21 and the separator cover 22, and then the fiber material layer 41 may be attached to the mesh member 42 surface.

  FIG. 6 shows a first comparative example (a) in which the collision plate 32 is composed only of a hard plate-like member 51, a second comparative example (b) in which a fiber material layer 41 is provided on the surface of the hard plate-like member 51, and It is explanatory drawing which showed the flow of the blowby gas and oil mist in Example (c) of this invention in contrast. Arrow G indicates the flow of blow-by gas, and arrow M indicates the flow of oil mist.

  As shown in the drawing, in the first comparative example corresponding to the conventional configuration of FIG. 1 (a), the oil mist M advances straight through the passage hole 30, collides with the plate member 51, and grows into a large droplet here. . The blow-by gas G changes the flow direction along the plate member 51 and flows to the opening 33 between the plate member 51 and the bottom surface of the separator chamber 23.

  The basic flow of the blow-by gas G and the oil mist M is the same in the second comparative example of FIG. 2B in which the fiber material layer 41 is provided on the surface of the hard plate member 51, and the blow-by gas G is downward. The direction of flow is changed, and the flow flows to the opening 33 between the collision plate 32 and the bottom surface of the separator chamber 23. The oil mist M goes straight through the passage hole 30, collides with the fiber material layer 41 and the plate-like member 51, and drops downward as a large liquid droplet.

  On the other hand, in the embodiment of the present invention shown in FIG. 2C, most of the blow-by gas G that has traveled straight with the oil mist M from the passage hole 30 and collided with the fiber material layer 41 is mostly the fiber material layer 41 and the net-like shape. It passes through the member 42 as it is and flows downstream. Then, a part of the blow-by gas G flows around the opening 33 between the collision plate 32 and the bottom surface of the separator chamber 23 as indicated by a broken line arrow. Part of the oil mist M collides with the surface of the fiber material layer 41 and is separated, and the remaining part is captured while passing through the fiber material layer 41, and drops downward when it grows into large droplets. In addition, when the fiber material layer 41 is extremely thin or when the fiber material layer 41 is extremely rough, the oil mist M blows through the fiber material layer 41, so that such a blow-out does not occur. Fineness and thickness of the eyes are required.

  As described above, in the present invention, the collision plate 32 that receives the high-speed blow-by gas flow through the passage hole 30 is composed of the fiber material layer 41 and the mesh member 42, and the blow-by gas that has collided there can pass downstream. Further, it is possible to reduce the ventilation resistance and thus the pressure loss.

  FIG. 7 shows the oil separator 1 for the first comparative example, the second comparative example, and the embodiment of the present invention whose basic configuration is shown in FIGS. 6 (a), (b), and (c). The pressure loss was measured by changing the flow rate of the flowing gas, and the results were summarized. As shown in the figure, the pressure loss is clearly reduced in the example (c) compared to the first and second comparative examples (a) and (b).

  FIG. 8 is a summary of the results of measuring the oil mist capturing performance (capturing efficiency) with respect to the above-mentioned three components by passing a gas containing a constant oil mist at various flow rates. In addition, as the fiber material layer 41 of the 2nd comparative example, the same thing as the fiber material layer 41 of an Example was used. As shown in the figure, the second comparative example (b) including the fiber material layer 41 is superior in oil mist capturing performance as compared with the first comparative example (a) including only the simple hard plate-like member 51. However, in Example (c) of the present invention, higher capture performance was obtained than in the second comparative example (b). In the second comparative example, the blow-by gas flowing into the opening 33 includes a relatively large amount of oil mist as shown in FIG. 6B, whereas in the embodiment, the oil mist moves into the opening 33. This is thought to be because there are few detours.

  FIG. 9 shows the relationship between the oil mist trapping performance and the pressure loss based on these measurement results, with the pressure loss on the horizontal axis and the oil mist trapping performance on the vertical axis. As shown in the figure, compared with the first and second comparative examples (a) and (b), the embodiment (c) of the present invention can obtain higher capture performance under the same pressure loss. That is, according to the present embodiment, it is possible to achieve both a high level of capture performance and pressure loss that are in a trade-off relationship with each other.

  As mentioned above, although one Example of this invention was described in detail, this invention is not limited to the said Example, A various change is possible. For example, in the above embodiment, the opening 33 is provided over the entire width of the collision plate 32, but the opening 33 is provided only in a part of the width of the collision plate 32, for example, the central portion in the width direction. It may be. Further, the outer shape of the mesh member 42 and the outer shape of the fiber material layer 41 do not necessarily coincide completely. For example, the opening 33 is provided only at the center in the width direction of the mesh member 42, and the fibers The material layer 41 may have a simple rectangular shape, and only the mesh member 42 may exist on both sides of the opening 33.

  2 and 3 show the housing portion 21 as a complete rectangular parallelepiped, however, in practice, it is generally a slightly different shape depending on the outer shape of the cylinder head cover 7 and the like.

DESCRIPTION OF SYMBOLS 1 ... Oil separator 7 ... Cylinder head cover 21 ... Housing part 22 ... Separator cover 23 ... Separator chamber 27 ... Partition 28 ... Inlet chamber 29 ... Outlet chamber 30 ... Passage hole 32 ... Colliding plate 33 ... Opening 35 ... Drain pipe 41 ... Fiber Material layer 42 ... Mesh member

Claims (2)

An oil separator provided in a cylinder head cover of an internal combustion engine, for separating oil mist from blow-by gas taken out through the cylinder head cover,
A separator chamber having a blow-by gas inlet at one end and a blow-by gas outlet at the other end;
A partition wall provided to partition the separator chamber into an inlet chamber on the blow-by gas inlet side and an outlet chamber on the blow-by gas outlet side, and a plurality of passage holes formed therethrough;
A collision plate provided in the outlet chamber adjacent to the partition wall so as to face the passage hole;
An opening provided in a slit shape between the lower end of the collision plate and the bottom surface of the separator chamber, over a part or the whole of the width of the collision plate;
A drain portion for discharging the separated oil from the bottom surface of the separator chamber into the valve chamber of the internal combustion engine;
With
An oil separator for an internal combustion engine, characterized in that the collision plate is composed of a fiber material layer on the surface facing the passage hole, and a mesh member on the back side that supports the fiber material layer.   The oil separator for an internal combustion engine according to claim 1, wherein the fiber material layer is made of a nonwoven fabric.

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