JP2017066907A - Oil mist separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil mist separator capable of suppressing rise of crank case internal pressure during low rotation/low load operation of a diesel engine, and capable of enhancing oil mist collecting performance during high rotation/high load operation in which a large amount of oil mist is generated.SOLUTION: An oil mist separator 1A for separating and removing oil in blow-by gas BG which is generated in a diesel engine in a separator chamber 11 includes a collision plate 13 which is provided in the separator chamber, a first nozzle 14 and a second nozzle 15 which are provided in the separator chamber to face the collision plate and inject the blow-by gas to the collision plate, and an opening and closing valve 16 for opening and closing an opening of the second nozzle in accordance with a flow rate of the blow-by gas flowing in the separator chamber.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an oil mist separator that separates and removes oil in blow-by gas generated in a diesel engine in a separator chamber.

  In a diesel engine, an oil mist separator that removes oil in blow-by gas is provided in the blow-by gas path, but the intake pipe negative pressure is small during low-speed / low-load operation such as idling, and blow-by gas The flow rate that is inhaled is small. In this state, if the pressure loss of the oil mist separator is large, the flow rate of the blow-by gas to be sucked is further reduced, so that the pressure in the crankcase may be greatly increased. When the crankcase internal pressure rises, the oil pressure at the bottom of the crankcase also rises, which may cause oil leakage from each seal part of the engine.

  Therefore, in order to suppress an increase in the crankcase internal pressure, it is conceivable to reduce the pressure loss of the oil mist separator. However, when the pressure loss is reduced, for example, when the oil mist separator is of a collision type, the collision speed of the oil mist with the collision plate is reduced, so that the oil mist collecting performance by the oil mist separator is lowered. For this reason, the oil mist cannot be efficiently removed at the time of high rotation / high load operation where the flow rate of blow-by gas is large and the amount of generated oil mist is large. As a result, the amount of oil consumed by taking out increases. Conversely, if the pressure loss of the oil mist separator is increased in order to efficiently remove oil mist during high-speed / high-load operation, the crankcase internal pressure will increase during low-speed / low-load operation.

  In this regard, Patent Document 1 proposes a blow-by gas reduction device provided with a bypass passage without a control valve as a bypass in addition to a normal blow-by gas passage provided with a control valve. According to this device, the changeover valve selectively switches to one of the above passages according to the crankcase internal pressure, and the crankcase internal pressure is set to a predetermined value by the sensor during low-speed / low-load operation where the crankcase internal pressure is relatively large. When it is detected that the pressure exceeds the upper limit, the auxiliary passage is opened, and the increase in the crankcase internal pressure is suppressed. On the other hand, the blow-by gas passage is opened by the switching valve at the time of high rotation / high load operation where the crankcase internal pressure is relatively small. Thus, according to this device, the crankcase internal pressure can be properly maintained.

Japanese Utility Model Publication No.59-159715

  However, although the device of Patent Document 1 can properly maintain the crankcase internal pressure by switching with the switching valve, the oil mist separator itself does not change during any operation, so the oil mist collecting performance is improved. I can't let you.

  Further, the device of Patent Document 1 requires a switching valve for selectively switching between the blow-by gas passage and the sub-passage in addition to the addition of the sub-passage, and further, a diaphragm and a vacuum tank for operating the switching valve Further, switching means including a solenoid valve, a pressure switch, and the like are necessary, and the system is complicated and the number of parts is large.

  Therefore, the present invention has a simple configuration and can suppress an increase in the crankcase internal pressure by reducing its own pressure loss during low-speed / low-load operation where the crankcase internal pressure is severely restricted. An object of the present invention is to provide an oil mist separator capable of improving the oil mist collecting performance during high rotation and high load operation with a large amount of generation.

In order to solve the above problem, an invention according to claim 1 is an oil mist separator that separates and removes oil in blow-by gas generated in a diesel engine in a separator chamber, and an impact plate provided in the separator chamber; A first nozzle and a second nozzle that are provided in the separator chamber so as to face the collision plate and inject blow-by gas into the collision plate; and the first nozzle and the second nozzle according to a flow rate of the blow-by gas flowing into the separator chamber. The gist of the invention is to provide an on-off valve that opens and closes the opening of the two nozzles.
According to a second aspect of the present invention, in the first aspect of the present invention, the second nozzle is connected to an accommodating portion that accommodates the float valve that is the on-off valve so as to be movable up and down. In accordance with the flow rate of the blow-by gas flowing into the separator chamber, it is lifted and lowered between a rising position for closing the opening of the second nozzle and a falling position for opening the opening of the second nozzle. To do.
According to a third aspect of the present invention, in the second aspect of the present invention, a blow-by gas inflow hole is formed in the bottom plate of the housing portion, and the float valve has a main body opposed to the inflow hole. A closing portion provided on the upper side of the main body and closing the opening of the second nozzle; and provided on the outer peripheral side of the inflow hole of the bottom plate of the housing portion, protruding from the lower side of the main body. The gist is to include a plurality of legs.
In order to solve the above problem, an invention according to claim 4 is an oil mist separator that separates and removes oil in blow-by gas generated in a diesel engine in a separator chamber, and includes a first centrifuge and a second centrifuge. A separator, a first introduction pipe connected to a cylindrical separator body of the first centrifuge and introducing blowby gas into the separator body from a tangential direction; and a cylindrical shape of the second centrifuge A second introduction pipe connected to the separator body for introducing blowby gas into the separator body from a tangential direction, and a flow rate of blowby gas flowing into the first centrifuge and the second centrifuge. The gist of the invention is that it comprises an on-off valve that opens and closes the opening of the second introduction pipe.

According to the oil mist separator of the present invention, a collision plate provided in the separator chamber, a first nozzle and a second nozzle that are provided in the separator chamber so as to face the collision plate, and inject blow-by gas into the collision plate, and the separator chamber And an on-off valve that opens and closes the opening of the second nozzle in accordance with the flow rate of the blow-by gas flowing into the nozzle. Thereby, at the time of low rotation / low load operation with a small flow rate of blow-by gas, both the first nozzle and the second nozzle are opened, and the opening area of the entire nozzle is large, so the pressure loss of the oil mist separator is reduced, The increase in crankcase internal pressure can be suppressed. On the other hand, during high rotation and high load operation where the flow rate of blow-by gas is high, the opening / closing valve closes the opening of the second nozzle and the opening area of the entire nozzle becomes small, so the pressure loss of the oil mist separator increases and the oil mist increases. The collection performance is improved. Moreover, it can be made a simpler structure as compared with the conventional one in which the blow-by gas passage and the auxiliary passage are provided on the downstream side of the oil mist separator.
In addition, the second nozzle is connected to an accommodating portion that accommodates the float valve that is the on-off valve so that the float valve can be moved up and down, and the float valve is configured according to the flow rate of blow-by gas flowing into the separator chamber. Correlation between the weight of the float valve and the flow rate of blow-by gas flowing into the separator chamber when the lift is lifted and lowered between the rising position for closing the opening of the second nozzle and the falling position for opening the opening of the second nozzle. Thus, the opening of the second nozzle can be opened and closed, so that the number of parts can be reduced and the configuration can be further simplified.
In addition, a blow-by gas inflow hole is formed in the bottom plate of the housing portion. When the float valve includes a main body, a closing portion, and a plurality of leg portions, the flow rate of the blow-by gas depends on the flow rate. The float valve can be operated sensitively.

  According to another oil mist separator of the present invention, the blow-by gas is connected to the first and second centrifugal separators and the cylindrical separator body of the first centrifugal separator from the tangential direction in the separator body. A first introduction pipe for introducing a blow-by gas from a tangential direction into the separator main body connected to the cylindrical separator body of the second centrifuge, a first centrifuge, An on-off valve that opens and closes the opening of the second introduction pipe in accordance with the flow rate of blow-by gas flowing into the second centrifuge. Thereby, at the time of low rotation and low load operation with a low flow rate of blow-by gas, both the first introduction pipe and the second introduction pipe are opened, and the opening area of the whole introduction pipe is large, so the pressure loss of the oil mist separator is It becomes smaller and the rise of the crankcase internal pressure is suppressed. On the other hand, during high rotation and high load operation where the flow rate of blow-by gas is large, the opening / closing valve closes the opening of the second introduction pipe and the opening area of the whole introduction pipe becomes small, so the pressure loss of the oil mist separator increases, Oil mist collection performance is improved. Moreover, it can be made a simpler structure as compared with the conventional one in which the blow-by gas passage and the auxiliary passage are provided on the downstream side of the oil mist separator.

The present invention will be further described in the following detailed description with reference to the drawings referred to, with reference to non-limiting examples of exemplary embodiments according to the present invention. Similar parts are shown throughout the several figures.
It is the schematic of the oil mist separator of embodiment of this invention, (a) is the state at the time of the low flow rate of blow-by gas, (b) shows the state at the time of the high flow rate of blow-by gas. It is a top view of the on-off valve of FIG. It is sectional drawing by the AA cutting line of FIG. It is a general view of the blow-by gas recirculation path of an engine. It is the schematic of the oil mist separator in another embodiment of this invention. It is the schematic which shows the oil mist separator in another embodiment of this invention. It is the schematic which shows the oil mist separator in another embodiment of this invention.

  The items shown here are exemplary and illustrative of the embodiments of the present invention, and are the most effective and easy-to-understand explanations of the principles and conceptual features of the present invention. It is stated for the purpose of providing what seems to be. In this respect, it is not intended to illustrate the structural details of the present invention beyond what is necessary for a fundamental understanding of the present invention. It will be clear to those skilled in the art how it is actually implemented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The oil mist separator separates and removes oil in blow-by gas generated in a diesel engine. In this embodiment, the oil mist separator is a collision type that separates and removes oil by colliding blow-by gas with a collision plate. Further, here, the oil mist separator is exemplified by the one externally attached to the upper portion of the head cover.

  In FIG. 1, the oil mist separator 1 </ b> A has a separator chamber 11 partitioned by a horizontal partition plate 12, and a collision plate 13 made of a filter is provided in the separator chamber 11. A non-woven fabric, a woven fabric, a porous body or the like is used for the filter. The collision plate 13 is disposed above the partition plate 12 at a predetermined distance, and the first nozzle 14 and the second nozzle 15 are separated from the partition plate 12 at a position facing the collision plate 13 by a predetermined distance. It is attached. Among these, the second nozzle 15 is provided with an on-off valve 16 that opens and closes the opening of the second nozzle 15 according to the flow rate of the blow-by gas BG. That is, the first nozzle 14 does not have the on-off valve 16, and the second nozzle 15 has the on-off valve 16.

  In the present embodiment, the collision plate 13 made of a filter (specifically, a breathable filter) is exemplified, but the present invention is not limited to this. For example, the collision plate 13 is provided integrally or separately on the wall forming the separator chamber 11. A collision plate made of a wall (specifically, a non-breathable wall) may be employed. Further, for example, a filter (specifically, a breathable filter) attached to a collision surface side of a collision plate made of a wall (specifically, a non-breathable wall) may be employed. Furthermore, in this embodiment, although the common collision plate 13 arrange | positioned facing the 1st and 2nd nozzles 14 and 15 was illustrated, it is not limited to this, For example, facing the 1st nozzle 14 You may make it provide the 1st collision board arrange | positioned and the 2nd collision board arrange | positioned facing the 2nd nozzle 15. FIG.

  The diameters of the nozzles 14 and 15 are set corresponding to the desired blow-by gas flow rate and pressure loss, and those of 2 to 6 mm are used in this embodiment. However, the nozzle diameter is not limited to this value. The oil mist separator 1A is often provided with several nozzles, but for convenience of explanation, in FIG. 1, one each of the first nozzle 14 and the second nozzle 15 is provided. Indicates.

  A bottom partition plate 17 is formed below the separator chamber 11, and the blow-by gas passage 37 is moved upward from the crankcase 35 shown in FIG. 3 to the side of the bottom partition plate 17 and flows into the head cover 39. An inlet 18 through which the gas BG flows is formed. In the upper part of the separator chamber 11, an outlet 19 through which blow-by gas BG that has flowed in the separator chamber 11 flows out is provided. The hole diameter of the outlet 19 is set in accordance with the desired blow-by gas flow rate and pressure loss, and in this embodiment, the hole diameter is 10 to 20 mm in relation to the nozzle diameter. However, the hole diameter of the outlet 19 is not limited to this value.

  The second nozzle 15 is connected to an accommodating portion 20 that accommodates the open / close valve 16 so as to be movable up and down between an elevated position (see FIG. 1B) and a lowered position (see FIG. 1A). An inflow hole 22 through which blow-by gas BG flows from below is provided at the center of the bottom plate 21 of the housing unit 20. Further, the bottom partition plate 17 is provided with an oil discharge hole 23 through which the oil OL separated and removed in the separator chamber 11 is discharged. The oil discharge hole 23 extends downward from the discharge hole 23 and is located below the crankcase 35. An oil discharge passage 24 communicating with the pan 44 is formed.

  The on-off valve 16 is composed of a float valve made of synthetic resin, metal, or the like. As shown in FIG. 2, the outer shape is substantially spherical at the center portion of the upper surface of the main body 16a formed of a substantially cross-shaped flat plate in plan view. A hemispherical closing portion 16b is formed in a shape in which it is integrally mounted. The on-off valve 16 is disposed in the accommodating portion 20 so that the main body 16 a faces the inflow hole 22. Since the upper surface of the closing portion 16b is formed in a substantially spherical surface, the closing portion 16b abuts the entire periphery of the opening of the second nozzle 15 even if the opening / closing valve 16 is inclined to the raised position, and the opening of the opening 16 is opened. It can be reliably plugged. However, the float valve is not necessarily limited to this shape, and may have a shape in which the upper portion is pointed in a conical shape. The on-off valve 16 is further provided with rectangular plate-like leg portions 16c protruding downward at four locations on the peripheral end portion of the bottom surface of the main body 16a. The bottom surface of the leg portion 16c is placed in contact with the outer peripheral side of the inflow hole 22 of the bottom plate 21 of the storage chamber 20 when the engine is stopped and when the blow-by gas BG is at a low flow rate, because the on-off valve 16 is in the lowered position. The

Next, the flow of the blow-by gas BG in the blow-by gas recirculation path of the diesel engine provided with the oil mist separator 1A configured as described above will be described.
In the engine 31 and blow-by gas recirculation path shown in FIG. 4, blow-by gas BG generated in the combustion chamber 32 of the engine 31 leaks into the crankcase 35 from the gap between the outer peripheral surface of the piston 33 and the inner peripheral surface of the cylinder 34. Thereafter, the blow-by gas passage 37 is moved upward from the lower portion of the cylinder block 36 by the intake pipe negative pressure, and flows into the cylinder head cover 39 from the cylinder head 38. Then, after the oil component is separated and removed while passing through the oil mist separator 1A attached to the head cover 39, it merges with the upstream fresh air purified by the air cleaner 41, compresses the intake air, and compresses the combustion chamber It is sent to a turbocharger 42 that is an intake supercharger forcibly sent to 32, further cooled by an intercooler 43, and returned to the combustion chamber 32 through an intake pipe passage 40.

Next, the operation of the oil mist separator 1A will be described.
Since the intake pipe negative pressure is small when the engine 31 is at a low flow rate such as idling or other low rotation / low load operation, as shown in FIG. Since the weight of the on-off valve 16 is larger than the suction force due to the intake pipe negative pressure, it is placed on the bottom plate 21. At this time, the main body 16a is separated from the bottom plate 21 and faces the inflow hole 22, and a gap is formed between each leg portion 16c. Therefore, the path from the bottom of the bottom plate 21 through the inflow hole 22 to the inside of the storage chamber 20 is in a communication state. Accordingly, the blow-by gas BG flowing from the lower side of the bottom plate 21 passes through the gaps between the leg portions 16 c from the inflow holes 22 and is guided into the storage chamber 20, and is further ejected from the second nozzle 15 into the separator chamber 11. It is possible. On the other hand, the first nozzle 14 is not provided with the opening / closing valve 16 below and is always open, so that the blow-by gas BG flowing from the inlet 18 can always be ejected into the separator chamber 11. Thus, when the blow-by gas BG is at a low flow rate, both the first nozzle 14 and the second nozzle 15 are open and jettable.

  On the other hand, when the engine 31 is at a high flow rate with a high rotation and a high load, as shown in FIG. 1B, the on-off valve 16 provided below the second nozzle 15 has a bottom plate due to the suction force caused by the negative pressure of the intake pipe. The upper surface of the hemispherical body 16 b comes into contact with the opening at the lower end of the second nozzle 15. As a result, the opening of the second nozzle 15 is closed, and the blow-by gas BG below the bottom plate 21 is interrupted on the way from the inflow hole 22 of the bottom plate 21 to the second nozzle 15 and the separator chamber 11. . Therefore, when the blow-by gas BG is at a high flow rate, only the first nozzle 14 is open and can be ejected into the separator chamber 11.

Next, the operation of the oil mist separator 1A will be described.
Since the oil mist separator 1A is a collision type, the pressure loss of the oil mist separator itself and the oil mist collecting performance are determined by the total opening area of the first nozzle 14 and the second nozzle 15 combined. Here, in the oil mist separator 1A, (pressure loss = pressure at the inlet 18−pressure at the outlet 19).

  Now, when the engine 31 is in a low flow rate state with low rotation and low load, the suction pipe negative pressure is small, so the force for sucking the blow-by gas BG is small, and the blow-by gas BG tends to stay in the crankcase 35. However, as described above, both the first nozzle 14 and the second nozzle 15 are open during the low rotation / low load operation, and the opening area of the entire nozzle is large. For this reason, since the speed at which the blow-by gas BG is ejected from each nozzle and collides with the collision plate 13 is small and the pressure loss of the oil mist separator 1A is small, the blow-by gas BG flows smoothly. As a result, an increase in the internal pressure of the crankcase 35 due to a large amount of blow-by gas BG remaining in the crankcase 35 can be suppressed. Then, when the internal pressure of the crankcase 35 rises, the pressure of the lubricating oil at the bottom of the crankcase 35 rises and oil leakage from the lubricating portion is prevented.

  On the other hand, if both nozzles are always set in such an open state as described above, the pressure loss of the oil mist separator 1A itself can be obtained even when the engine 31 is in a high flow rate state of high rotation and high load. Since it is still small, the collection performance of the oil mist in the blow-by gas BG will not be improved.

  However, in the oil mist separator 1A of the present embodiment, the opening of the second nozzle 15 is closed by the on-off valve 16 when the engine 31 is in a high flow rate state with high rotation and high load, and the opening area of the entire nozzle is Is halved compared to low rotation and low load. For this reason, the pressure loss of the oil mist separator 1A is large, and the blow-by gas BG collides with the collision plate 13 at a high speed, so that the oil mist collection rate increases. Accordingly, the oil mist collecting performance is improved during high rotation and high load operation where the amount of oil mist generated is large, and this can prevent an increase in oil consumption due to taking out.

  In the meantime, in the oil mist separator 1A shown in FIG. 1, the first nozzle 14 and the second nozzle 15 are provided one by one. For example, two first nozzles 14 and second nozzles 14 are provided. If one nozzle 15 is provided, it is assumed that all nozzles have the same conditions such as the same diameter and weight. A total of three nozzles were opened before the switching of the on-off valve 16, but after the switching, 1 The openings of the second nozzles 15 are closed, and only the two first nozzles 14 are opened. For this reason, the opening area as a whole nozzle becomes 2/3 after switching. In addition, when both the above-mentioned 1st nozzle 14 and the 2nd nozzle 15 are one, the opening area as the whole nozzle becomes 1/2 after switching. Thus, the opening area as the whole nozzle after switching of the on-off valve 16 can be varied by varying the number of nozzles of the first nozzle 14 and the second nozzle 15 in various ways.

  In addition, when each of the first nozzle 14 and the second nozzle 15 is one, the opening area of the entire nozzle rapidly decreases to ½ immediately after the switching of the on-off valve 16, and the pressure loss of the oil mist separator 1A is Increases rapidly. On the other hand, if a plurality of nozzles are provided as the second nozzle 15 and the weights of the respective float valves are made different from each other so that the nozzles are sequentially closed, the entire nozzle immediately after the switching of the on-off valve 16 is achieved. The change in the opening area can be made gentle.

Next, the oil mist separator 1A is a collision type, but it can also be a cyclone type.
The cyclone type oil mist separator 1B separates and removes the oil in the blow-by gas BG by centrifugal separation by swirling. As shown in FIG. 5, the first centrifugal separation is provided in the separator chamber 51 of the oil mist separator 1B. A vessel 52 and a second centrifuge 53 are provided side by side in the horizontal direction. An inflow port 55 through which blow-by gas BG flows is provided in the bottom plate portion 54 that partitions the separator chamber 51, and an outflow port 66 through which blow-by gas BG flows out is provided above the separator chamber 51.

  The centrifugal separators 52 and 53 are vertically installed, and the cylindrical separator body 56 is formed of a container 57 having an inverted truncated cone shape. An inflow hole 58 is provided in the upper part of the peripheral wall of the container 57. One end sides of the first introduction pipe 67 and the second introduction pipe 68 in the separator chamber 51 are connected to the inflow hole 58, and the first and second introduction pipes are connected. The blow-by gas BG which has flowed through the pipes 67 and 68 flows in a tangential direction with respect to the peripheral wall. An oil discharge hole 60 is formed in the central portion of the bottom plate portion 54 of the separator body 56, and a gas discharge hole 62 is formed in the central portion of the upper lid portion 61. Further, in the internal space of the separator body 56, a discharge pipe 63 penetrating the gas discharge hole 62 hangs down along the central axis, and the lower end of the discharge pipe 63 extends from the bottom plate portion 54 to a position above a predetermined distance. ing. And the accommodating part 20 which accommodated the on-off valve 16 which consists of a float valve is connected to the middle of the 2nd inlet pipe 68 of the 2nd centrifuge 53. FIG. The discharge pipe 63 penetrating through the lid portion 61 passes through the upper plate portion 64 of the separator chamber 51 and is connected to the discharge passage 65. The discharge passages 65 connected to the discharge pipes 63 from the first centrifuge 52 and the second centrifuge 53 merge together in the middle, and the merged portion is the above-described outlet 66. In the present embodiment, the cylindrical separator main body 56 having an inverted frustoconical shape is illustrated, but the present invention is not limited to this. For example, a cylindrical separator main body may be adopted.

  Here, the first introduction pipe 67 of the first centrifuge 52 in which the on-off valve 16 is not provided is always open. On the other hand, in the second introduction pipe 68 of the second centrifuge 53 provided with the on-off valve 16, the on-off valve 16 is lifted by the intake pipe negative pressure when the flow of blow-by gas increases, and the second introduction pipe 68 is opened. When it is closed by abutting on, it is closed.

  In the oil mist separator 1B configured as described above, the blow-by gas BG that has flowed into the separator chamber 51 from the inlet 55 passes through the first and second introduction pipes 67 and 68 and flows from the inlet hole 58 of the separator body 56 to the separator. After flowing into the inside from the tangential direction with respect to the peripheral wall of the main body 56, it turns along the peripheral wall. The heavy oil mist in the blow-by gas BG hits the peripheral wall due to centrifugal force and condenses, becomes liquid oil OL, flows downward along the peripheral wall, and is discharged from the oil discharge hole 60 of the bottom plate portion 54, and then the crankcase. 35 is returned to the oil pan 44 at the bottom.

  On the other hand, the blow-by gas BG from which the oil mist has been separated and removed is lightweight and flows downward while swirling around the center of the swirling flow. The blow-by gas BG moves upward through the opening at the lower end of the discharge pipe 63 and flows out through the discharge passage 65. After being discharged from 66, it is returned to the combustion chamber 32 through the intake pipe passage 40.

  Similarly to the collision type oil mist separator 1A, the cyclone type oil mist separator 1B also has the first introduction pipe 67 and the second introduction pipe 68 when the engine 31 is in a low flow rate state with low rotation and low load. Both of them are opened, and the blow-by gas BG is ejected from both the introduction pipes 67 and 68 into the separator main body 56 of the centrifugal separators 52 and 53 in the separator chamber 51. In this state, since the opening area of the entire introduction pipe is large, the pressure loss that is the difference between the pressure at the inlet 55 and the pressure at the outlet 66 of the oil mist separator 1B is small, and the internal pressure of the crankcase 35 increases. Is suppressed.

  On the other hand, when the engine 31 is in a high flow rate state of high rotation and high load, the opening of the second introduction pipe 68 is closed by the on-off valve 16, and the blow-by gas BG passes through the first introduction pipe 67 and is subjected to the first centrifugal separation. It is ejected only inside the separator body 56 of the separator 52. As a result, since the opening area of the entire introduction pipe is reduced to half that at the low flow rate, the pressure loss of the oil mist separator 1B is increased, and the blow-by gas BG is ejected from the first introduction pipe 67 into the separator body 56 vigorously. Is done. Thereby, the oil mist collection performance at the time of high rotation / high load operation with a large amount of generated oil mist increases.

  In the oil mist separator 1B shown in FIG. 5, two centrifuges are provided in the separator chamber 51, but three or more centrifuges may be provided. In the present embodiment, the first and second centrifuges 52 and 53 are provided in the separator chamber 51 into which blow-by gas is introduced. However, the present invention is not limited to this. For example, a virtual line in FIG. As shown, the one end sides of the first and second introduction pipes 67 and 68 may be connected to the inflow portion 70 into which blow-by gas flows.

  By the way, although the oil mist separator of each said embodiment has illustrated what was externally attached to the cylinder head cover 39, the oil mist separator may be externally attached to locations other than this. Further, not limited to the external attachment, for example, as shown in FIG. Alternatively, as shown by a portion surrounded by a broken line in FIG. 7, it may be incorporated in a separator chamber beside the crankcase 35 or the cylinder block 36. In the case of external attachment, it is possible to easily replace internal parts such as the collision plate 13 in the oil mist separator.

  The on-off valve 16 of each of the above embodiments performs nozzle open / close control using a natural force that causes the float valve to float by the difference between the intake pipe negative pressure and the float valve weight. The nozzle is not limited to the above, and a nozzle is used by detecting the internal pressure of the crankcase 35 or the rotational speed and load of the engine 31 with a sensor and sending the signal to the on-off valve 16 side, although not shown. The opening / closing operation of the opening may be controlled.

  Furthermore, when implementing this invention, you may provide the diaphragm valve for pressure regulation in a blow-by gas path | route.

  The foregoing examples are for illustrative purposes only and are not to be construed as limiting the invention. Although the invention has been described with reference to exemplary embodiments, it is to be understood that the language used in the description and illustration of the invention is illustrative and exemplary rather than limiting. As detailed herein, changes may be made in its form within the scope of the appended claims without departing from the scope or spirit of the invention. Although specific structures, materials and examples have been referred to in the detailed description of the invention herein, it is not intended to limit the invention to the disclosure herein, but rather, the invention is claimed. It covers all functionally equivalent structures, methods and uses within the scope.

  The present invention is not limited to the embodiments described in detail above, and various modifications or changes can be made within the scope of the claims of the present invention.

  The present invention is widely used as a technique for separating and removing oil in blow-by gas generated in a diesel engine.

  1A, 1B; oil mist separator, 11; separator chamber, 13; collision plate, 14; first nozzle, 15; second nozzle, 16; on-off valve, 16a; body, 16b; Separator chamber, 52; first centrifuge, 53; second centrifuge. 56; Separator body, 67; First introduction pipe, 68; Second introduction pipe, BG; Blow-by gas

Claims (4)

An oil mist separator that separates and removes oil in blow-by gas generated in a diesel engine in the separator chamber,
A collision plate provided in the separator chamber;
A first nozzle and a second nozzle that are provided in the separator chamber so as to face the collision plate and inject blow-by gas into the collision plate;
An oil mist separator comprising: an on-off valve that opens and closes the opening of the second nozzle according to the flow rate of blow-by gas flowing into the separator chamber. The second nozzle is connected to an accommodating portion that accommodates the float valve that is the on-off valve so as to be movable up and down.
The float valve is raised and lowered between a raised position for closing the opening of the second nozzle and a lowered position for opening the opening of the second nozzle in accordance with the flow rate of blow-by gas flowing into the separator chamber. The oil mist separator according to claim 1. An inflow hole for blow-by gas is formed in the bottom plate of the housing part,
The float valve includes a main body that faces the inflow hole, a closing portion that is provided on the upper side of the main body and closes the opening of the second nozzle, is provided to protrude below the main body, and The oil mist separator according to claim 2, further comprising: a plurality of legs placed on an outer peripheral side of the inflow hole of the bottom plate. An oil mist separator that separates and removes oil in blow-by gas generated in a diesel engine in the separator chamber,
A first centrifuge and a second centrifuge;
A first inlet pipe connected to the cylindrical separator body of the first centrifuge to introduce blow-by gas into the separator body from a tangential direction;
A second introduction pipe connected to the cylindrical separator body of the second centrifuge and introducing blow-by gas into the separator body from a tangential direction;
An oil mist separator comprising: an on-off valve that opens and closes an opening of the second introduction pipe in accordance with a flow rate of blow-by gas flowing into the first centrifuge and the second centrifuge.

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