JP4103047B2 - Oil separator and PCV system - Google Patents

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 a 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 particles to become 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 reduced to the internal combustion engine side. At this time, if gas-liquid separation is insufficient, oil consumption increases, and various gas-liquid separation structures have been proposed.

  As an example, Patent Document 1 describes an apparatus configured to have a plurality of cyclone separators and change the number of separators to be used according to the flow rate of blow-by gas (crankcase ventilation gas). Specifically, the volume flow of blow-by gas is divided into a plurality of partial flows, and each partial flow is independently circulated through different cyclone separators arranged in parallel.

In this conventional apparatus, since the volume flow of the blow-by gas depends on the load state of the internal combustion engine, etc., the above-described configuration makes it possible to remove the blow-by gas under optimum conditions regardless of the fluctuation of the volume flow. Is intended to do.
Japanese translation of PCT publication No. 2002-543321

  However, each cyclone separator provided in the above-mentioned conventional apparatus needs to be configured so that the maximum flow rate of the partial flow introduced therein can be processed. On the contrary, if the capacity of the cyclone separator is determined in accordance with the lower limit of the partial flow range, the ventilation resistance tends to be excessive at a large flow rate, and the circulation tends to be hindered. .

  Therefore, even if the blowby gas is divided into partial flows, if the total flow rate or the partial flow rate is too small, the flow velocity becomes insufficient in the cyclone separator designed based on the maximum flow rate. In this case, the centrifugal force necessary for sufficient gas-liquid separation is not generated, and therefore the gas-liquid separation efficiency cannot be sufficiently increased.

  Further, if the number of cyclone separators is increased by dividing the flow into partial flows, not only the configuration of the apparatus becomes complicated, but also a wider installation space is required. For example, this is extremely disadvantageous when mounted in a limited space such as a vehicle, and increases the member cost of the apparatus.

  Further, Patent Document 1 also discloses a configuration using a ball valve for preventing the partial flow from flowing through the cyclone separator when the partial flow is small. However, in the first place, when the blow-by gas flow before division is too small, it is difficult to obtain sufficient gas-liquid separation performance even with such a configuration.

  Therefore, the present invention has been made in view of such circumstances, an oil separator capable of realizing sufficient gas-liquid separation performance regardless of the flow rate of the fluid used for gas-liquid separation, and simplifying the device configuration, and the An object of the present invention is to provide a PCV system using this.

  In order to solve the above problems, an oil separator according to the present invention is a cyclone-type oil separator that is supplied with a fluid containing an oil component and a gas component to perform gas-liquid separation, and has a substantially cylindrical body portion; A gas-liquid separation part that is defined so that the length along the height direction of the body part changes in accordance with the flow rate of the fluid in the body part, and a direction in which the fluid forms a predetermined angle with the radial direction of the body part A fluid suction part provided so as to flow into the gas-liquid separation part, an oil discharge part provided below the trunk part, and an oil discharge part from which the oil separated from the fluid is discharged to the outside of the oil separator; A gas discharge unit provided above the discharge unit and configured to discharge a gas component separated from the fluid to the outside of the oil separator.

  Note that the “height direction” of the body portion indicates a direction perpendicular or substantially perpendicular to a surface including a direction in which fluid is supplied to the inside of the sidewall of the body portion, and generally has a substantially cylindrical shape. It is the axial direction (direction perpendicular to the radial direction) of the body portion formed, and in this case, the length along the height direction corresponds to “height”.

  The oil separator according to the present invention configured as described above functions as a tangential inflow type cyclone separator in which the fluid flows from the body wall, particularly when the inflow angle is substantially perpendicular to the radial direction of the body. That is, the fluid that is a gas-liquid mixture is guided to the fluid suction portion and flows into the gas-liquid separation portion defined therein from the tangential direction of the trunk portion, and gas-liquid separation is performed by the cyclone effect. The separated oil component flows along the inner wall of the body part to the oil discharge part provided below the body part and is collected and discharged to the outside. On the other hand, the separated gas component (clear processed gas) is discharged from the gas discharge portion to the outside of the trunk portion.

  At this time, for example, when the flow rate is relatively small, the gas-liquid separation unit changes its length along the height direction of the body portion according to the fluid flow rate, and the reverse. When the flow rate is relatively large, the cross-sectional diameter is defined to be large. As a result, the volume of the gas-liquid separation unit is changed according to the fluid flow rate, a sufficient flow velocity is secured in the gas-liquid separation unit even when the fluid flow rate is small, and an increase in ventilation resistance is suppressed even when the fluid flow rate is large. Therefore, it is not necessary to divide the fluid into partial flows, and it is not necessary to use a plurality of oil separators.

  Specifically, it is preferable that the body portion is provided with a plurality of side walls having different inner diameters along the height direction of the body portion. In this case, when the flow rate is relatively small, a space region surrounded by a side wall having a smaller inner diameter is used as the gas-liquid separation unit, and when the flow rate is relatively large, instead of or in addition to that part. Thus, a space region surrounded by a side wall having a larger inner diameter is used as the gas-liquid separator.

  In addition, a plurality of regions are defined in the internal space of the oil separator, and the oil separator is provided at a position higher than the fluid suction portion inside the trunk portion and in the height direction of the trunk portion, along the height direction. It is preferable to further include a partition member that is movable and that has a communication portion that is open so that the plurality of regions communicate with each other.

  In this way, among the plurality of space regions separated by the partition member, the region to which the fluid is supplied from the fluid inflow portion functions as a gas-liquid separation portion, and the fluid from which the oil component has been separated passes through the communication portion and the intake system Etc. In addition, since the partition member is provided so as to move along the height direction of the body portion, the volume of the gas-liquid separation unit is variable, and the gas-liquid separation unit having an appropriate volume according to the fluid flow rate is provided. Can be formed.

  The method or means for moving the partition member is not particularly limited, but it is useful if the partition member is provided so as to be freely movable at a position higher than the fluid suction portion. In this way, when the fluid is supplied to the gas-liquid separation unit, a force determined by the pressure of the fluid supplied to the region on the fluid suction unit side and the pressure receiving area of the partition member acts on the partition member. And since the partition member is provided so that it can move freely, it moves to the direction of the force, ie, the other area side separated by the partition member, without providing a separate drive means.

  In this case, it is more preferable to provide an elastic member such as various springs or rubber that is disposed in a region where the gas-liquid separation part is not defined among the plurality of regions and is provided so as to be in contact with the partition member.

  If comprised in this way, a partition member can contact | abut with an elastic member, when the pressure of the fluid is applied and it moves to the area | region side where the gas-liquid separation part is not defined. As a result, the elastic member is compressed, and the partition member is moved to a position where the repulsive force due to the compression of the elastic member and the force determined by the fluid pressure and the pressure receiving area of the partition member are balanced. The elastic member is a desired property parameter that is difficult to be compressed when the fluid flow rate is small, and is easily compressed when the fluid flow rate is large (for example, “spring constant” for a spring, “elastic modulus” for other members, etc.) ) Is preferable.

  In addition, the same effect | action can be show | played even if it comprises at least one part of a partition member with an elastic body, without using an elastic member. An example of this elastic body is a rubber having a continuous or intermittent smooth surface or an irregular surface such as a bellows, and selected from various synthetic rubbers or natural rubbers depending on the type of fluid supplied and temperature conditions. It can be used. Another example is a non-rubber material having a foldable uneven surface such as a bellows.

  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, sufficient gas-liquid separation ability can be realized regardless of the flow rate of the fluid used for gas-liquid separation, and the apparatus configuration is simplified and the installation space is reduced. Can be achieved.

  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 and FIG. 2 are perspective views (partially block diagrams) schematically showing a preferred embodiment of a PCV system including an oil separator according to the present invention, each of which is supplied with blow-by gas having different flow rates. It is a figure which shows the state of a separator. Moreover, FIG. 3 is a figure which shows the principal part of the cross section which follows the III-III line | wire in FIG.1 and FIG.2. The PCV system 1 includes a cyclone separator 2 (oil separator) connected to an internal combustion engine 101 and an intake system 102 in a vehicle, moving equipment, or the like (not shown).

  The cyclone separator 2 communicates with the cylindrical portions 21 and 22 having different inner diameters via an annular coupling portion 29 formed so that the diameter gradually decreases toward the cylindrical portion 21 (so-called “tapering”). It has a joined body. A gas suction port 3a is provided on the side wall of the cylindrical portion 21, and a gas suction pipe 3 (fluid suction port) connected to the gas suction port 3a via, for example, a crankcase (not shown) of the internal combustion engine 101 via a pipe P1. Part) is connected.

  The upper end of the cylindrical portion 22 is provided with a lid portion 23 having a through hole formed at a substantially central portion thereof, and the gas exhaust pipe 4 (connected to the intake system 102 via a pipe P2 is provided in the through hole. Gas exhaust part) is inserted. A funnel-shaped inverted conical portion 28 is provided at the lower end of the cylindrical portion 21. An oil discharge port 5a is formed at the lower end portion of the inverted conical portion 28, and an oil discharge pipe 5 (oil discharge portion) connected to the oil recovery system 103 via a pipe P3 is connected to the oil discharge port 5a. It is connected.

  In addition, a partition plate 24 (partition member) having an outer diameter that is substantially the same as the inner diameter of the cylindrical portion 22 and that has a gas flow port 24a is provided. Between the partition plate 24 and the lid portion 23, there is a coil spring 25 disposed in the cylindrical portion 22 of the gas discharge pipe 4 and a coil spring 25 disposed substantially coaxially with the gas flow port 24 a. is set up. One end and the other end of the coil spring 25 are coupled to the bottom surface of the lid portion 23 and the top surface of the partition plate 24, respectively.

  In this way, the partition plate 24 is held in a state of being suspended by the coil spring 25, and is higher than the gas suction port 3a to which the gas suction pipe 3 is connected inside the trunk and in the height direction thereof. It is provided in the part (here in the cylindrical part 22). Due to the partition plate 24, the internal space of the cyclone separator 2 is vertically separated into two space regions S1 and S2, and the upper and lower space regions communicate with each other through the gas circulation port 24a.

  The space area S1 on the side where the gas inlet 3a is formed is surrounded by a space surrounded by the cylindrical portion 21 and the inverted conical portion 28, and a cylindrical portion 22 and a partition plate 24 having a larger inner diameter communicating with the space. And functions as a blow-by gas gas-liquid separation chamber (gas-liquid separation unit). Further, since the coil spring 25 expands and contracts, the partition plate 24 can move in the vertical direction in the figure, thereby changing the volumes of the space regions S1 and S2.

  Processing of blow-by gas in the PCV system 1 configured as described above will be described below. The blow-by gas is a gas-liquid mixture of oil droplets (oil component) generated in the internal combustion engine 101 and combustion gas (gas component), and the flow rate changes according to the operating conditions of the internal combustion engine 101, and thus the gas. The flow velocity when reaching the suction port 3a is different.

  FIG. 1 shows the state of the cyclone separator 2 when blow-by gas B1 (fluid) having a relatively small flow rate is supplied, and FIG. 2 shows that blow-by gas B2 (fluid) whose flow rate is significantly larger than blow-by gas B1. The state of the cyclone separator 2 when supplied is shown. FIG. 3 shows both states together. Moreover, in the drawing, the length of the arrows representing the blow-by gases B1, B2 schematically shows the magnitude of the flow velocity in both.

  The cyclone separator 2 is a tangential inflow type. In FIG. 1, blow-by gas B1 is supplied through the gas suction pipe 3 into the cylindrical portion 21 along the tangential direction. When the blow-by gas B1 flows into the cylindrical portion 21, an internal pressure generated according to the gas flow rate is applied to the inner wall of the cylindrical portion 21 and the partition plate 24 that define the space region S1 that is a gas-liquid separation chamber. The

  At this time, since the flow velocity of the blow-by gas B1 is relatively small, the internal pressure in the cylindrical portion 21 does not increase so much, and the force acting on the lower surface of the partition plate 24 (the area of the lower surface of the partition plate 24 is set to the internal pressure of the space region S1). The multiplied value) is not so large that the coil spring 25 is contracted significantly, and a space mainly having a volume surrounded by the cylindrical portion 21, the annular connecting portion 29, and the inverted conical portion 28 as shown in FIG. Region S1 is defined as a gas-liquid separation chamber.

  The flow of the blow-by gas B1 introduced into the space region S1 changes from a linear flow to a vortex flow mainly in the cylindrical portion 21, and descends in a spiral shape while rotating along the inner wall of the cylindrical portion 21. Then, when it reaches the inverted conical portion 28, it further descends while increasing the rotation speed, reversely rises near the lower end of the inverted conical portion 28, and rises while rotating the substantially central portion of the cylindrical portion 21.

  At this time, the oil droplets contained as fine particles in the blow-by gas B1 obtain centrifugal force by the swiveling motion, move in the horizontal direction toward the side wall of the cylindrical portion 21, and collide with the inner wall of the cylindrical portion 21 to move. Lost and flowed down the inner wall. The oil collected in the vicinity of the oil discharge port 5a at the lower end of the inverted conical portion 28 is sent to the oil recovery system 103 through the oil discharge pipe 5 by an appropriate operation.

  In this way, the gas-liquid separation of the blow-by gas B1 is performed, and the gas rising in the substantially central portion of the cylindrical portion 21 becomes a clarified gas from which oil droplets are separated, and passes through the gas circulation port 24a formed in the partition plate 24. It flows into the space region S2 and is further sent to the intake system 102 through the gas discharge pipe 4 and the pipe P2.

  Thus, when the flow velocity of the blow-by gas B1 is relatively small, the partition plate 24 held near the lower end of the cylindrical portion 22 so as to be suspended by the coil spring 25 does not move upward, and the space region S1 is A relatively small volume is maintained. Therefore, even if the flow rate of the blow-by gas B1 is small, the vortex flow velocity in the cyclone separator 2 can be sufficiently secured. Thereby, sufficient centrifugal force can be generated in the cyclone separator 2, and excellent gas-liquid separation performance can be expressed even with a small flow rate of the blowby gas B1.

  On the other hand, when the blow-by gas B2 having a flow rate sufficiently larger than the blow-by gas B1 flows into the cylindrical portion 21, the flow velocity is relatively large, so that the internal pressure in the cylindrical portion 21 is increased and acts on the lower surface of the partition plate 24. The force to be increased is such that the coil spring 25 is contracted significantly. As a result, the coil spring 25 contracts so that the volume of the space region S2 decreases, and as shown in FIG. 2, the volume is expanded, that is, most of the cylindrical portion 22, the annular connecting portion 29, the cylindrical portion 21, A space region S1 surrounded by the inverted conical portion 28 is defined as a gas-liquid separation chamber. At this time, the partition plate 24 moves to a position where the force acting on the lower surface of the partition plate 24 and the repulsive force due to the contraction of the coil spring 25 are balanced, and is held at that position.

  The flow of the blow-by gas B2 introduced into the space region S1 changes from a linear flow to a vortex flow mainly in the cylindrical portions 21 and 22 and the cylindrical portion 22, and the cylindrical portion 22, the annular connecting portion 29, and the cylindrical portion 21 While rotating along the inner wall, it descends spirally. Then, when it reaches the inverted conical portion 28, it further descends while increasing the rotation speed, reversely rises near the lower end of the inverted conical portion 28, and rises while rotating substantially the center portions of the cylindrical portions 21, 22.

  At this time, oil droplets contained as fine particles in the blow-by gas B2 are separated in the same manner as the gas-liquid separation of the blow-by gas B1 described above, and flow down along the inner walls of the cylindrical portions 21, 22, etc. The oil is sent from the outlet 5 a to the oil recovery system 103 through the oil discharge pipe 5. Further, the clarified gas from which the oil droplets have been separated flows into the space region S2 through the gas flow port 24a formed in the partition plate 24, and is further sent to the intake system 102 through the gas discharge pipe 4 and the pipe P2. It is done.

  Thus, when the flow velocity of the blow-by gas B2 is relatively large, the partition plate 24 held near the lower end of the cylindrical portion 22 so as to be suspended by the coil spring 25 moves upward, and the space region S1 is cylindrical. The volume is enlarged by enlarging the portion 22 side. Therefore, even if the flow rate of the blow-by gas B2 is large, it is possible to realize a sufficient flow velocity while suppressing the fluid resistance (venting resistance) in the space region S1 from becoming excessive.

  Note that the actual airflow of the blow-by gases B1 and B2 in the space region S1 tends to exhibit a more complicated behavior, and the action is not limited to that described above.

  Thus, according to the cyclone separator 2 and the PCV system 1 including the cyclone separator 2, even if the flow rates of the blow-by gases B1 and B2 change, the gas-liquid separation efficiency can be maintained sufficiently high over a wide range of the flow rates. Therefore, it is not necessary to divide the blow-by gas containing the oil component into partial flows before the gas-liquid separation as in the prior art, or it is not necessary to use a plurality of oil separators. As a result, the configuration of the PCV system 1 can be simplified, the installation space can be reduced, and the cost can be reduced.

  Further, the body of the cyclone separator 2 is formed by connecting a cylindrical portion 21 and a cylindrical portion 22 having a larger inner diameter through an annular connecting portion 29, and the partition plate 24 is supplied with blow-by gases B1 and B2. When it is not, it is disposed on the lower end side of the cylindrical portion 22 having the larger inner diameter. Therefore, it is possible to reduce the amount of upward movement of the partition plate 24 necessary to increase the volume of the space region S1 as desired. Therefore, the height of the cyclone separator 2 can be reduced, and thereby the installation space in the height direction can be further reduced.

  Further, the partition plate 24 is held movably by a coil spring 25 installed outside the region functioning as a gas-liquid separation chamber, that is, in the other space region S2 separated by the partition plate 24, and blow-by gas B1. , B2 and the repulsive force (spring force) of the coil spring 25 are moved to a desired position. Therefore, it is not necessary to provide another drive mechanism for moving the partition plate 24. Therefore, the apparatus configuration can be further simplified, and an increase in cost can be suppressed.

  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, instead of or in addition to the coil spring 25, other types of springs or other elastic members such as rubber may be used. Alternatively, the partition plate 24 may be driven by providing another drive mechanism without providing the coil spring 25. In this case, the flow rate or flow velocity of the blow-by gas B1, B2 supplied into the cylindrical portion 21 is measured, and based on the actual measurement value, the movement amount of the partition plate 24 is adjusted to form the space region S1 having a desired volume. It is preferable to control to define.

  The cyclone separator 2 is preferably a tangential inflow type, but is not limited thereto, and may be connected so as to form a certain angle with the radial direction of the cylindrical portion 21. Even in this case, the blowby gases B1 and B2 flow into the inside from the direction that forms a predetermined angle with the radial direction of the cylindrical portion 21, so that a sufficient cyclone effect is produced in the space region S1.

  Furthermore, you may comprise the trunk | drum of the cyclone separator 2 by only one of the cylindrical parts 21 and 22. FIG. In this case, the partition plate 24 is disposed at an appropriate position in each of the cylindrical portions 21 and 22. Furthermore, the cylindrical portions 21 and 22, the gas circulation port 24a, and the fitting portion of the gas discharge pipe 4 in the cylindrical portion 22 may be provided eccentric to each other without being provided coaxially.

  The oil separator according to the present invention and the PCV system including the oil separator can realize sufficient gas-liquid separation performance regardless of the flow rate of the fluid that is the target of gas-liquid separation, and can prevent the complexity of the apparatus configuration and the deterioration of economic efficiency. Therefore, it can be widely used in equipment, motives, equipment, and the like equipped with an internal combustion engine that can generate a gas-liquid mixture containing oil such as blow-by gas.

It is a perspective view (partial block diagram) showing typically a suitable embodiment of a PCV system provided with an oil separator by the present invention, and is a figure showing the state where blowby gas B1 is supplied. It is a perspective view (partial block diagram) showing typically a suitable embodiment of a PCV system provided with an oil separator by the present invention, and is a figure showing the state where blow-by gas B2 is supplied. It is a figure which shows the principal part of the cross section which follows the III-III line in FIG.1 and FIG.2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... PCV system, 2 ... Cyclone separator (oil separator), 3 ... Gas suction pipe (fluid suction part), 3a ... Gas suction port, 4 ... Gas discharge pipe (gas discharge part), 5a ... Oil discharge port, 5 ... Oil discharge part, 5 ... Oil discharge pipe (oil discharge part), 21, 22 ... Cylindrical part (body part), 23 ... Lid part, 24a ... Gas distribution port, 24 ... Partition plate (partition member), 28 ... Reverse cone , 29 ... annular connecting part, 101 ... internal combustion engine, 102 ... intake system, 103 ... oil recovery system, B1, B2 ... blow-by gas (fluid), P1, P2, P3 ... piping, S1 ... space region (gas-liquid separation) Chamber, gas-liquid separator).

Claims (5)

A cyclone type oil separator in which a gas-liquid separation is performed by supplying a fluid containing an oil component and a gas component,
A substantially cylindrical body,
A gas-liquid separation part defined so that the length along the height direction of the body part changes according to the flow rate of the fluid in the body part;
A fluid suction part provided so that the fluid flows into the gas-liquid separation part from a direction forming a predetermined angle with a radial direction of the body part;
An oil discharge part that is provided below the body part and from which the oil component separated from the fluid is discharged to the outside of the oil separator;
A gas discharge part provided above the oil discharge part, wherein the gas component separated from the fluid is discharged to the outside of the oil separator;
Oil separator equipped with. The body portion is provided with a plurality of side walls having different inner diameters along the height direction of the body portion.
The oil separator according to claim 1. A plurality of regions are defined in the internal space of the oil separator, provided inside the barrel and at a position higher than the fluid suction portion in the height direction of the barrel, and in the height direction. And a partition member formed with a communicating portion that is movable so as to communicate with each other.
The oil separator according to claim 1 or 2. Among the plurality of regions, the gas-liquid separation unit is disposed in a region that is not defined, and includes an elastic member provided so as to be in contact with the partition member.
The oil separator according to claim 3. The oil separator according to any one of claims 1 to 4 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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