JP2005113799A - Oil separator and PCV system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil separator capable of achieving sufficient gas-liquid separation efficiency when performing fluid gas-liquid separation, and improving the degree of freedom in arrangement design while suppressing generation of extra friction in an internal combustion engine, and the use thereof Provided PCV system.
A PCV system includes an oil separator connected to an internal combustion engine, an intake system, and an oil recovery system. In the oil separator 1, a support shaft 6 is provided in a casing 10, and impellers 71 to 73 having a plurality of blades 7,.
[Selection] Figure 1

Description

  The present invention relates to an oil separator and a PCV (Positive Crankcase Ventilation) system including the oil separator.

  In general, blowby gas leaking into the crankcase from between a piston and a cylinder in a compression process or an expansion process of an internal combustion engine is mixed with mist-like oil to become an oil mist. As described above, the blow-by gas containing the oil component and the gas component is usually subjected to gas-liquid separation, and then the oil component is recovered and the gas component is returned to the internal combustion engine. At this time, if gas-liquid separation is insufficient, oil consumption increases, and various gas-liquid separation structures have been proposed as oil separators.

As an example, Patent Document 1 describes a structure in which a centrifuge having a rotating body fixed to a shaft connected to an engine camshaft is provided in the middle of a blow-by gas passage. According to such a conventional structure, the blow-by gas collides with a rotating body that is rotated by driving of the engine, and the oil and gas in the blow-by gas are centrifuged by the mass difference between the two.
JP-A-4-234512

  However, in the gas-liquid separation structure according to the above-described prior art, the camshaft rotated by the engine drive is used as the power for rotating the rotating body of the centrifuge, so that the friction is inconvenient in the system including the engine. May increase. Moreover, since it is necessary to connect the rotating shaft (shaft) of a rotary body to a camshaft, the location where a centrifuge is installed will be restricted.

  Therefore, the present invention has been made in view of such circumstances, and when performing gas-liquid separation of fluid, sufficient gas-liquid separation performance can be realized, generation of extra friction in an internal combustion engine can be suppressed, and An object of the present invention is to provide an oil separator capable of improving the degree of freedom in design and a PCV system using the same.

  In order to solve the above-described problems, an oil separator according to the present invention is supplied with a fluid containing an oil component and a gas component to perform gas-liquid separation, and is separated from an inlet and a fluid into which the fluid is introduced. And a casing provided with a gas discharge port through which the gas component is discharged and an oil discharge port through which the oil component separated from the fluid is discharged, and is rotatable in the casing so as to follow the fluid flow direction. A support shaft that is fixedly disposed, and a rotation portion that is provided on the support shaft so as to intersect with the fluid flow path and that is rotated by the fluid flow pressure.

  In the oil separator configured as described above, when a fluid, which is a gas-liquid mixture of an oil component and a gas component, is supplied into the casing through the inlet, a circuit provided so as to intersect the fluid flow path. The fluid collides with the moving part. As a result, the oil component in the fluid loses most of the momentum and adheres to the rotating part, and the gas component mainly moves downstream and is discharged to the outside from the gas discharge port.

  The rotating part is rotated by the fluid flow pressure (fluid pressure). Strictly speaking, a part of the kinetic energy of the fluid is applied to the rotating part. Thereby, the oil component adhering to the rotating part moves in the outer peripheral direction of the rotating part by centrifugal force, and is discharged to the outside through the inner wall of the casing. In this way, since the fluid itself that is the target of gas-liquid separation is used to rotate the rotating portion, no other power source is required.

  Here, the rotating part may or may not be fixed to the support shaft. In the former case, by providing a bearing at at least one end of the support shaft, the support shaft functions as a rotating shaft that rotates together with the rotating portion. On the other hand, in the latter case, by providing the rotating portion so as to be slidable with the outer surface of the support shaft, the support shaft functions as a fixed shaft positioned at the center of rotation of the rotating portion. In this case, specifically, an annular member is provided at the center of the rotating part, and the support shaft is loosely inserted into the annular member, or the annular member is loosely fitted to the support shaft outer wall and rotatably held. Can be illustrated.

  More specifically, the rotating part preferably has an impeller including a plurality of blades (rotary blades). In this way, the rotating part functions as a turbine. That is, each blade of the impeller receives the fluid, and the impeller efficiently rotates by itself at an angular velocity corresponding to the flow rate of the fluid and the flow velocity. Therefore, since the rotational speed is increased as the fluid flow rate is increased, high gas-liquid separation efficiency can be achieved even when the fluid flow rate is large.

  Further, the rotating unit has a configuration in which adjacent blades (rotary blades) among the plurality of blades have a gap (a constant interval) and a part of the blades overlaps in the fluid flow direction. It is more preferable that it is provided. In other words, when viewed in the direction of fluid flow (usually along the support shaft), one of the two adjacent blades appears to overlap the other. It is preferable that a plurality of blades are disposed on the support shaft.

  If comprised in this way, the collision with a fluid and a blade | wing can be made more reliable compared with the case where there is no overlap of blade | wings. Therefore, the gas-liquid separation efficiency is further improved. That is, if there is no overlap between the blades, a part of the fluid may not be received by the blades and may pass through as it is. On the other hand, when part of the blades is provided so as to overlap, almost all of the fluid can be received by the blades. Further, since the blades are arranged at a constant interval without contacting each other in the overlapping portion, there is no inconvenience that the flow of gas is blocked.

  The PCV system according to the present invention includes the oil separator according to the present invention, and is configured such that blow-by gas generated from the internal combustion engine as a fluid is supplied to the oil separator.

  According to the oil separator of the present invention and the PCV system using the oil separator, since the fluid to be gas-liquid separated is used as the power of the rotating part, it is possible to suppress the generation of extra friction in the internal combustion engine and to limit the installation space. Therefore, it is possible to improve the degree of freedom of installation and the degree of freedom of design by eliminating the inconvenience.

  Hereinafter, embodiments of the present invention will be described in detail. In addition, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a perspective view (partially block diagram) schematically showing a preferred embodiment of a PCV system including an oil separator according to the present invention.

  The PCV system 100 includes an oil separator 1 connected to an internal combustion engine 101 and an intake system 102 provided in a vehicle, moving equipment, or the like (not shown). In the oil separator 1, a support shaft 6 is provided in a substantially cylindrical casing 10, and impellers 71 to 73 (rotating portions) are connected to the support shaft 6.

  The casing 10 has a hollow and substantially cylindrical shape, and the internal combustion engine 101 is not illustrated, for example, in an inlet 3a formed in one wall (a wall positioned upstream of the flow of the blow-by gas G) having a substantially conical shape. A suction pipe 3 connected to the crankcase via a pipe P1 is coupled. In addition, an outlet pipe 4 is connected to an intake system 102 via a pipe P2 at a gas discharge port 4a formed in an upper portion of the casing 10 on the other side wall (a wall located on the downstream side of the flow of blow-by gas G). ing.

  Further, an oil discharge port 5a is formed in the lower portion of the body wall of the casing 10 (the wall constituting the cylindrical body) in the vicinity of the other wall, and an open / close valve (not shown) is provided in the oil discharge port 5a. ) And a discharge pipe 5 connected to the oil recovery system 103 via a pipe P3. In addition, the lower part of the trunk wall of the casing 10 is inclined downward from one wall toward the other wall.

  Further, the spindle 6 has a cylindrical or rod-like (cylindrical in the figure) body 62 fixed to the tip of a cone-shaped head 61 and a base end provided on the other wall of the casing 10. It is held by the bearing 63. As a result, the support shaft 6 is coaxial with the casing 10 and is rotatable about the axis.

  Further, the impellers 71 to 73 are disposed so as to protrude from the body portion 62 of the support shaft 6 toward the body wall of the casing 10 at regular intervals. Here, FIG. 2 is a cross-sectional view showing a main part taken along line II-II in FIG. 1 and FIG. 3 to be described later.

  In the present embodiment, each impeller 71, 72, 73 is composed of eight blades (blade, turbine blade) 7,... Having a curved surface shape, and adjacent ones among these blades are gaps. They are provided so as to overlap each other in the flow direction of the blow-by gas G (fluid) (the axial direction of the support shaft 6). That is, as shown in FIG. 2, when viewed in the direction of flow of the blow-by gas G, one of the two adjacent blades 7, 7 appears to overlap with the other. Eight blades 7 are arranged on the support shaft 6.

  Processing of blow-by gas G by the PCV system 100 having such a configuration will be described below mainly with reference to FIG. The blow-by gas G is a gas-liquid mixture of oil droplets (oil component) generated in the internal combustion engine 101 and combustion gas (gas component), that is, oil mist, and usually has a flow rate according to the operating conditions of the internal combustion engine 101. Changes.

  The blow-by gas G is supplied into the casing 10 from the inlet 3a of the oil separator 1 through the pipe P1 and the suction pipe 3, passes through a flow path defined by the casing 10 and the support shaft 6, and crosses the flow path. It flows to the other wall side of the casing 10 provided with the gas discharge port 4a while sequentially passing through the impellers 71 to 73 provided at. In FIG. 1, the flow is schematically indicated by an arrow H.

  The blow-by gas G that has reached the impellers 71 to 73 hits the plurality of blades 7,. At that time, fine oil droplets contained in the blow-by gas G lose momentum and temporarily adhere to the blades 7. At the same time, in other words, a part of the kinetic energy of the blow-by gas G is applied to the blades 7 by the pressure (wind pressure) of the blow-by gas G, and the impellers 71 to 73 are rotated about the support shaft 6. In the present embodiment, since the impellers 71 to 73 are coupled to the support shaft 6 and the support shaft 6 is held by the bearing 63, the impellers 71 to 73 and the support shaft 6 rotate integrally. Is done.

  When the impellers 71 to 73 rotate, centrifugal force acts on the oil droplets attached to the surface of the blades 7 and moves on the surfaces of the impellers 71 to 73 in the outer peripheral direction. The oil droplets are eventually blown off from the blades 7 and discharged onto the body wall of the casing 10, and are collected along the wall surface at the lower part of the body part of the casing 10.

  The accumulated oil 9 flows down due to the downward inclination of the lower portion of the body portion of the casing 10, and is discharged from the oil discharge port 5 a to the outside of the casing 10, as schematically shown by the wavy arrow J in the figure. It is sent to the recovery system 103.

  In this way, the gas-liquid separation is performed while the blow-by gas G flows along the direction schematically indicated by the arrow H as it blows through the gap between the blades 7 of the impellers 71 to 73. The clarified gas from which the oil droplets have been separated and removed is discharged from the gas discharge port 4a to the outside of the casing 10, and is sent to the intake system 102 through the outlet pipe 4 and the pipe P2. It is assumed that the actual airflow in the casing 10 can take a more complicated path.

  According to the oil separator 1 configured as described above and the PCV system 100 including the oil separator 1, the impellers 71 to 73 are rotated by the blow-by gas G that is a gas-liquid separation target, and thus the impellers 71 to 73 are driven. No other power source is needed to make it happen. Therefore, it is not necessary to adopt a conventional structure in which the support shaft 6 is fixed to the camshaft or the like of the internal combustion engine 101. Therefore, an increase in friction in the internal combustion engine 101 can be suppressed.

  Further, since it is not necessary to connect the internal combustion engine 101 in order to drive the oil separator 1 as described above, the apparatus configuration can be simplified, the installation space can be reduced and the cost can be reduced, and the arrangement design of the oil separator 1 can be achieved. Can greatly improve the degree of freedom.

  Furthermore, since the impellers 71 to 73 are used as the rotating part, the wind pressure of the blow-by gas G can be efficiently used for the rotating operation of the blades 7. Moreover, since the rotational speed of the impellers 71 to 73 is increased as the flow rate of the blow-by gas G and the flow velocity is increased, sufficiently high gas-liquid separation efficiency can be realized even if the blow-by gas G has a large flow rate.

  Furthermore, since the impellers 71 to 73 are arranged such that two adjacent blades 7 and 7 are overlapped toward (along) the flow direction of the blowby gas G, a part of the blowby gas G is disposed. Can be prevented from passing through without being received by the blades 7. Therefore, almost all of the blow-by gas G can be received by the blades 7, and the gas-liquid separation performance can be further improved. Furthermore, since the two blades 7 and 7 are arranged with a certain gap in the overlapping part, the blow-by gas G and the gas-liquid separated gas component move downstream through the gap. it can. Therefore, since the blow-by gas G is not shut off, it is possible to prevent a decrease in processing speed that may be caused by the occurrence of such shut-off.

  Furthermore, since the conical head 61 is provided on the support shaft 6, the supplied blow-by gas G can be easily distributed to the impeller 71 side. Therefore, a decrease in the flow rate on the upstream side of the casing 10 can be suppressed. In addition, since the lower part of the trunk portion of the casing 10 is inclined, the accumulated oil 9 can be efficiently collected.

  FIG. 3 is a perspective view (partially block diagram) schematically showing another preferred embodiment of a PCV system including an oil separator according to the present invention. The PCV system 200 has the same configuration as the PCV system 100 shown in FIG. 1 except that it includes an oil separator 2 instead of the oil separator 1. The oil separator 2 is configured in the same manner as the oil separator 1 except that the casing 20 is provided instead of the casing 10.

  The casing 20 is formed by forming annular grooves (annular recesses) M1 to M3 at portions facing the impellers 71 to 73 on the inner wall of the trunk portion. If it says from another viewpoint, the cyclic | annular protrusion T1-T3 will be formed in the site | part which does not oppose the impellers 71-73 in the inner wall of a trunk | drum. That is, the casing 10 is provided with annular irregularities alternately along the flow direction of the blow-by gas G.

  Also in the oil separator 2 configured as described above and the PCV system 200 including the same, the same excellent effects as the oil separator 1 and the PCV system 100 including the oil separator 1 described above are exhibited. In addition, in order to avoid duplication about them, description here is abbreviate | omitted.

  Here, FIG. 4 is a perspective view showing a lower part inside the trunk of the casing 20. As described above, in the oil separator 2, the annular grooves M1 to M3 are provided at positions facing the impellers 71 to 73. Therefore, the oil droplets adhering to the impellers 71 to 73 are discharged onto the annular grooves M1 to M3 facing each other, and flow down along the annular grooves M1 to M3. As shown in FIG. 4, the flow of the oil 9 that reaches the lower part of each annular groove M <b> 1 to M <b> 3 and accumulates to some extent joins in a passage D formed in the body portion of the casing 20 and is discharged to the outside from the oil discharge port 5 a. Is done.

  By the way, in the oil separator 1 shown in FIG. 1, if the pressure in the vicinity of the gas discharge port 4 a is excessively negative due to the suction of the intake system 102, the oil component adhering to the inner wall of the casing 10 moves to the intake system 102 side. There is a possibility that the gas will be drawn in, that is, moved in the flow direction of the blow-by gas G along the inner wall and sent to the intake system 102 together with the clarified gas.

  Although such inconvenience can be sufficiently suppressed by adjusting the negative pressure, if the annular grooves M1 to M3 are provided in the casing 20 like the oil separator 2, the annular grooves M1 to M3 are formed along the flow direction of the blow-by gas G. Since the annular protrusions T1 to T3 are formed between each of them, they serve as a barrier to prevent the oil component from moving toward the gas discharge port 4a. Therefore, the oil component can be sufficiently prevented from being sent to the intake system 102 together with the clarified gas, and the oil 9 can be more efficiently accumulated to further increase the oil recovery rate.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible in the limit which does not change the summary. For example, the number of impellers 71 to 73 is not limited to three, but may be one or two, and may be provided in multiple stages. Further, the number and shape of the blades 7 are not limited to those shown in the figure, and the number of blades may be plural, and the shape may be a shape that is established as the impellers 71 to 73. Furthermore, although it is desirable that the blades 7 are arranged so as to overlap as described above, they do not have to overlap.

  Furthermore, the support shaft 6 may be a fixed shaft. That is, if the impellers 71 to 73 are provided so as to be freely movable with respect to the support shaft 6, the support shaft 6 can be fixed to the other walls of the casings 10 and 20, and in that case, the bearing 63 becomes unnecessary. Specifically, for example, there is a method in which the blades 7,... Are joined to an annular member such as a ring, and an annular groove or the like in which the annular member can be loosely fitted is provided in the trunk portion of the support shaft 6. Even in this case, since the impellers 71 to 73 are rotated by the blow-by gas G, the gas-liquid separation performance can be sufficiently improved.

  Furthermore, in the oil separator 2, an arc-shaped groove may be provided in an upper part of the casing 20 instead of the annular grooves M <b> 1 to M <b> 3 that form a complete ring shape. In this case, even if the gas discharge port 4a vicinity becomes excessively negative pressure, the oil 9 that reaches the lower part of the trunk of the casing 20 and accumulates to some extent has a relatively large distance to the gas discharge port 4a. It ’s hard to be pulled in easily. In addition, the introduction port 3 a and the suction pipe 3 may be eccentric from the support shaft 6 and connected to one wall of the casings 10 and 20. In that case, the head 61 of the spindle 6 may not be conical. Moreover, the shape of the casings 10 and 20 is not limited to a cylindrical shape, and may be a rectangular tube shape, for example.

  The oil separator according to the present invention and the PCV system equipped with the oil separator use the fluid that is the target of gas-liquid separation as the power of the rotating part, so that it is possible to suppress the generation of extra friction in the internal combustion engine and to eliminate the installation space restriction. Therefore, the degree of freedom in arrangement design can be improved, and therefore, it can be widely used in equipment, motives, equipment, and the like including an internal combustion engine that can generate a gas-liquid mixture containing an oil component such as blow-by gas.

1 is a perspective view (partially block diagram) schematically showing a preferred embodiment of a PCV system including an oil separator according to the present invention. It is sectional drawing which shows the principal part which follows the II-II line | wire in FIG.1 and FIG.3. It is a perspective view (partial block diagram) showing typically other suitable embodiments of a PCV system provided with an oil separator by the present invention. 3 is a perspective view showing a lower part inside the trunk part of the casing 20. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Oil separator, 3 ... Intake pipe, 3a ... Inlet port, 4 ... Outlet pipe, 4a ... Gas discharge port, 5a ... Oil discharge port, 5 ... Discharge pipe, 6 ... Support shaft, 7 ... Blade, 9 ... Oil, DESCRIPTION OF SYMBOLS 10,20 ... Casing, 61 ... Head (support axis), 62 ... Trunk part (support axis), 71, 72, 73 ... Impeller (rotating part), 100, 200 ... PCV system, 101 ... Internal combustion engine, DESCRIPTION OF SYMBOLS 102 ... Intake system, 103 ... Oil recovery system, D ... Passage, G ... Blow-by gas (fluid), P1, P2, P3 ... Pipe, M1, M2, M3 ... Annular groove, T1, T2, T3 ... Annular projection.

Claims (4)

An oil separator in which a fluid containing oil and gas is supplied to perform gas-liquid separation,
A casing provided with an inlet for introducing the fluid, a gas outlet for discharging the gas separated from the fluid, and an oil outlet for discharging the oil separated from the fluid;
A support shaft that is rotatably or fixedly arranged in the casing so as to be along the flow direction of the fluid;
A rotating portion that is provided on the support shaft so as to intersect with the fluid flow path, and is rotated by the fluid flow pressure;
Oil separator equipped with. The rotating part has an impeller including a plurality of blades.
The oil separator according to claim 1. The rotating portion is provided such that adjacent blades of the plurality of blades have a gap and a part of the blades overlaps in the fluid flow direction.
The oil separator according to claim 2. The oil separator according to claim 1 is provided,
Blowby gas generated from an internal combustion engine as the fluid is supplied to the oil separator;
PCV system.

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