Oil mist separator

Abstract

The object of the present invention is to reduce or prevent oil in an oil mist separator from being carried away. The invention relates to an oil mist separator for a PCV system of an internal combustion engine. The oil mist separator comprises an inlet for allowing blow-by gas to flow in, an outlet for discharging blow-by gas, a bottom plate forming a flow path for circulating blow-by gas between the inlet and the outlet, an impinger for separating oil from blow-by gas, an oil discharge portion disposed below the bottom plate and having an oil discharge port area for receiving the separated oil, and a plurality of baffle plates for capturing oil, formed on an upper surface of the bottom plate between the impinger and the outlet, wherein an oil storage section for temporarily storing oil captured by the baffle plates is partially disposed on at least one side of the plurality of baffle plates in a short side direction of the bottom plate.

Description

Technical Field

[0001] This invention relates to an oil mist separator. Background Technology

[0002] In internal combustion engines such as vehicles, blow-by gases, consisting of incompletely burned gases, leak from the combustion chamber into the crankcase through the gap between the piston and cylinder. Therefore, PCV (positive crankcase ventilation) systems are known, in which blow-by gases are reintroduced into the combustion chamber by introducing them into the intake system, thereby preventing the release of incompletely burned gases into the atmosphere.

[0003] Since the blow-by gas contains a mist of oil components used to lubricate internal combustion engines, it is known to use an oil mist separator in the PCV system to separate the mist of oil contained in the blow-by gas.

[0004] Existing oil mist separators are configured to be housed within a cylinder head cover positioned above an internal combustion engine. These separators have an inlet for allowing blow-by gases to flow in and an outlet for discharging them. They also include a base plate that, together with the cylinder head cover, forms a flow path between the inlet and outlet for circulating the blow-by gases. Furthermore, they have an impeller on the base plate for separating oil mist and an oil drain section below the base plate, the drain section having an outlet area for receiving the separated oil.

[0005] In addition, a known configuration is in which a plurality of square U-shaped or plate-shaped capturing portions are formed on the base plate downstream of the impactor to block or capture oil, thereby preventing scattered oil from flowing out of the outlet (see, for example, Patent Document 1 and Patent Document 2).

[0006] In existing oil mist separators, when the flow rate of leaking gas is high, the leaking gas will flow back from the oil outlet of the oil discharge section, thereby spraying out the oil accumulated in the oil outlet area. The oil blocked by the square U-shaped or plate-shaped capture section will scatter, and eventually this oil will be carried to the discharge port. Therefore, there is still room for improvement in this regard.

[0007] Citation List Patent documents [Patent Document 1] JP 2014-092036 A [Patent Document 2] WO 2013 / 054578 A1 Summary of the Invention

[0008] The purpose of this invention is to reduce or prevent oil from being carried away in the oil mist separator.

[0009] According to an embodiment of the present invention, the above-mentioned problem is solved by an oil mist separator for a PCV system of an internal combustion engine, the oil mist separator being configured to be disposed in a cylinder head cover arranged above the internal combustion engine, the oil mist separator having an inlet for allowing blow-by gas to flow in and an outlet for discharging blow-by gas, and further having a base plate, the base plate forming together with the cylinder head cover to form a flow path for circulating the blow-by gas between the inlet and the outlet, wherein an impactor for separating oil from the blow-by gas is disposed on the base plate; an oil discharge section is disposed below the base plate, the oil discharge section having an oil discharge port area for receiving the separated oil; a plurality of baffles for capturing oil are formed on the upper surface of the base plate located between the impactor and the outlet; and an oil storage section for temporarily storing the oil captured by the baffles is partially disposed along the short side direction of the base plate on at least one side of the plurality of baffles.

[0010] As a result, a hydrodynamic stagnation occurs in the wake of the baffle, allowing oil scattering from the upstream side to be entrained and captured within this stagnation, potentially delaying its outflow from the outlet. Furthermore, when the leakage gas flow rate is high, oil overflowing from this stagnation can be blocked by an oil storage section located on one side of the baffle. This effectively prevents oil from flowing out of the oil mist separator and reduces or prevents oil carryover.

[0011] Preferably, a return oil passage connecting the oil storage section and the oil discharge section is also formed on the upper surface of the base plate.

[0012] Therefore, when the leakage gas flow rate is low, the oil accumulated in the oil storage section can flow efficiently to the oil discharge section, thereby further improving the performance of the oil mist separator.

[0013] Preferably, the oil storage section is formed as a trough inclined towards the downstream side.

[0014] Therefore, oil can be captured below the surface of the bottom plate, and the accumulated oil is not easily carried away by leaking gas, which can effectively reduce the oil spillage rate. In addition, when the leaking gas flow rate is low, oil from the oil storage section can flow smoothly.

[0015] Preferably, the impactor is composed of a perforated plate on the upstream side and an impact plate on the downstream side, with a gap extending along the short side of the base plate between the perforated plate and the impact plate, and the oil outlet area of ​​the oil discharge section is configured to be at least partially offset relative to the impactor along the short side of the base plate.

[0016] This ensures that space is provided directly behind the impactor for additional components to block or capture oil, thereby further improving the performance of the oil mist separator.

[0017] Preferably, a containment structure for blocking the separated oil is provided between the impactor and the plurality of baffles.

[0018] Therefore, the scattered oil can be blocked on the downstream side of the impactor, thereby further improving the performance of the oil mist separator.

[0019] Preferably, the enclosure structure is integrally formed with the perforated plate and impact plate of the impactor.

[0020] Therefore, the enclosure structure and the impactor can be integrally manufactured as a module, and the oil mist separator can be manufactured with higher efficiency.

[0021] Preferably, a gap is provided at the enclosure structure, through which oil from the downstream side can circulate.

[0022] Therefore, oil from the oil storage section can flow into the oil discharge section through the inside of the enclosure structure without bypassing the enclosure structure, thereby ensuring the shortest distance to the oil discharge section and optimizing the oil flow.

[0023] Preferably, the oil return passage is composed of a first outer return passage, a second outer return passage, and an inner return passage. The first outer return passage is defined by one sidewall of the enclosure structure in the short side direction of the base plate, and the second outer return passage is defined by another sidewall of the enclosure structure in the short side direction of the base plate. The inner return passage passes through the inner side of the enclosure structure between the gap of the enclosure structure and the gap of the impactor.

[0024] Therefore, by providing distribution channels, alternative flow paths for oil towards the discharge section can be offered. That is, even if blockages occur in some channels, oil can still flow into the discharge section through another channel, thus improving the reliability of the oil mist separator.

[0025] Preferably, the base plate is inclined such that the downstream side of the base plate is higher than the upstream side of the base plate.

[0026] This accelerates the flow of oil toward the discharge section and easily reduces the amount of oil flowing out of the oil mist separator. Attached Figure Description

[0027] Figure 1 (A) is a front view of an oil mist separator disposed in a cylinder head cover according to one embodiment, viewed from the short side direction. Figure 1 (B) is shown Figure 1 (A) Perspective view of the internal structure of the area enclosed by the dashed line.

[0028] Figure 2 This is a top-down perspective view of the periphery of the impactor of an oil mist separator according to one embodiment.

[0029] Figure 3 This is a perspective view of an oil mist separator according to one embodiment, viewed from the downstream side.

[0030] Figure 4 This is a perspective view of the periphery of the impactor of an oil mist separator according to one embodiment, viewed from the oblique downstream side. Detailed Implementation

[0031] Embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that the drawings in the following description are schematic, and the dimensional relationships or proportions between each element may differ from the actual situation. This includes cases where the relative dimensions and ratios of parts in the drawings may also differ.

[0032] Figure 1 (A) is a front view of an oil mist separator 100 disposed in a cylinder head cover 200 according to an embodiment of the present invention, viewed from the short side direction. The oil mist separator 100 is an oil mist separator for a PCV system of an internal combustion engine and is configured to be disposed in a cylinder head cover 200 disposed above the internal combustion engine. The oil mist separator 100 has an inlet 110 for allowing blow-by gas to flow in and an outlet 120 for discharging blow-by gas. The oil mist separator 100 also has a base plate 130, wherein an opening in the lower surface of the cylinder head cover 200 is closed by the base plate 130, thereby forming a flow path for circulating the blow-by gas between the inlet 110 and the outlet 120. In the figures, the flow of the blow-by gas is indicated by reference numeral 300. The terms "downstream" and "upstream" based on the flow of the blow-by gas are used hereinafter.

[0033] An impactor 140 for separating oil from leaked gas is provided on the base plate 130. The impactor 140, based on the principle of inertial impact, separates the gaseous oil mist contained in the leaked gas from the liquid oil. The impactor 140 consists of an upstream perforated plate 142 with multiple through holes and a downstream impact plate 144 opposite to the perforated plate 142. When the leaked gas passes through the holes in the perforated plate 142, the flow rate of the leaked gas increases, causing the leaked gas to inertially impact the impact plate 144, and the separated oil adheres to the surface of the impact plate. The adhered oil particles agglomerate and liquefy, thus dripping off. Below the leaked gas impact area of ​​the impact plate 144, an opening is formed at the impact plate 144 allowing gas and liquid to pass through. A gap 146 is provided between the perforated plate 142 and the impact plate 144, allowing the dripping oil to flow along the short side of the base plate 130.

[0034] An oil drain section 150 is disposed below the base plate 130. The oil drain section 150 extends along the base plate 130 between the inlet 110 and the outlet 120. The oil drain section 150 has an oil outlet region 152 for receiving oil separated by the impactor 140. The oil outlet region 152 includes an oil outlet and a generally funnel-shaped area surrounding the oil outlet.

[0035] Downstream of the impactor 140, a containment structure 170 is provided to block the flow of separated oil downstream. The containment structure 170 is formed as a wall that at least partially encloses a predetermined area downstream of the impactor 140. The containment structure 170 is positioned such that oil separated by the inertial impact of leaking gas at a downwardly suspended bypass plate 210 located on the cylinder head cover 200, and then dripping from the bypass plate 210, can also be received. That is, the predetermined area enclosed by the containment structure 170 is located below the bypass plate 210.

[0036] Figure 1 (B) is shown Figure 1 (A) is a perspective view of the internal structure of the area enclosed by the dashed line. Above the drain port area 152, at least one opening is formed in the base plate 130 for allowing oil to flow into the drain section 150. The drain port area 152, together with the opening in the base plate 130 above it, is positioned offset relative to the impactor 140 along the short side of the base plate 130, such that dripping oil flows into the gap 146 of the impactor 140. Above the at least one opening, a covering structure 160 is provided for partially covering the opening. Preferably, the covering structure 160 is provided at the downstream end of the opening formed on the farthest downstream side. The covering structure 160 consists of a downstream covering 162 for blocking the downstream-facing surface, an upper covering 164 for blocking the upward-facing surface, and a side surface covering 166 for blocking the side surface facing the short side of the base plate. Preferably, the side surface cover 166 is positioned relative to the base plate 130, with the opening of the cover structure 160 facing the impactor 140. In this case, the side surface of the cover structure 160 facing the side opposite to the impactor 140 is blocked by the wall of the enclosure structure 170.

[0037] Figure 2This is a perspective view, taken from above, of the periphery of the impactor 140 of an oil mist separator 100 according to one embodiment. The containment structure 170 has corresponding sidewall portions on both sides of the base plate 130 in the short-side direction, and a square U-shaped wall portion forming an oil storage area for temporarily blocking separated oil is also provided at the downstream end of the containment structure 170. Furthermore, a gap 172 is provided between the square U-shaped wall portion and one sidewall portion of the containment structure 170, through which oil from the downstream side can circulate while preventing oil leakage from the upstream side. The square U-shaped wall portion is located close to the other sidewall portion. Additionally, the containment structure 170 at least partially surrounds the cover structure 160 and at least a portion of the opening in the base plate 130 located above the oil discharge port area 152. If a plurality of openings for allowing oil to flow into the drain port area 152 are formed at the base plate 130, the containment structure 170 at least partially encloses at least one of the openings, preferably the opening provided with the cover structure 160. The containment structure 170 may be formed as a separate component relative to the impactor 140, or it may be integrally formed with the perforated plate 142 and the impact plate 144 of the impactor 140.

[0038] Figure 3 This is a perspective view of an oil mist separator 100 according to one embodiment, viewed from the downstream side. A plurality of baffles 180 for capturing oil are formed on the upper surface of the base plate 130 between the containment structure 170 and the outlet 120. When the leaking gas has a high flow rate, hydrodynamic stagnation may occur in the wake of the baffles 180, and oil scattering from the upstream side can be entrained and captured in this stagnation, and oil flowing out of the outlet 120 may be delayed. The baffles 180 are formed as plate-like members, and the width and height of each baffle 180 may be all the same or different from each other. The baffles 180 may be formed parallel to the short side direction of the base plate 130 or at an angle relative to the short side direction of the base plate 130. Furthermore, the baffles 180 may be formed at the center of the short side direction of the base plate 130 or near one side of the short side direction of the base plate 130.

[0039] An oil storage section 182 for temporarily storing oil captured by the baffles 180 is formed at least partially on at least one side of the plurality of baffles 180 along the short side direction of the base plate 130. The oil storage section 182 may be formed only on one side of the plurality of baffles 180, or it may be formed on both sides. Furthermore, a single oil storage section 182 may be formed along the longitudinal direction of the base plate 130, or multiple oil storage sections 182 may be formed. The oil storage section 182 is formed at the base plate 130 as a groove inclined towards the downstream side, wherein the inclination angle is preferably configured to be inclined relative to the installation angle, for example, not less than 1°. However, the oil storage section 182 may have other shapes, and may also be formed as a separate component to be installed at the base plate 130.

[0040] Figure 4 This is a perspective view of the periphery of the impactor 140 of an oil mist separator 100 according to one embodiment, viewed from the oblique downstream side. An oil return passage 190 is formed on the upper surface of the base plate 130, connecting the oil storage section 182 to the oil discharge section 150, such that when the leakage gas has a low flow rate, the oil accumulated in the oil storage section 182 flows to the oil discharge port region 152 of the oil discharge section 150. The oil return passage 190 branches into multiple passages at the region of the enclosure structure section 170. Preferably, the oil return passage 190 is composed of a first surrounding outer return passage 192, a second surrounding outer return passage 194, and a surrounding inner return passage 196. The first surrounding outer return passage 192 is defined by a sidewall portion of the enclosure structure section 170 in the short side direction of the base plate 130 and passes through the outer side of the enclosure structure section 170. The second surrounding outer return passage 194 is defined by another sidewall portion of the enclosure structure 170 in the direction of the short side of the base plate 130, and passes through the outer side of the enclosure structure 170. The surrounding inner return passage 196 passes through the inner side of the enclosure structure 170 between the gap 172 of the enclosure structure 170 and the gap 146 of the impactor 140.

[0041] The bottom plate 130 is tilted so that the downstream side of the bottom plate 130 is higher than the upstream side of the bottom plate 130, so as to promote the flow of oil toward the oil discharge section 150.

[0042] Next, the functions of the oil mist separator 100 and the leaking gas will be explained.

[0043] The leaking gas flowing in from the inlet 110 of the oil mist separator 100 along... Figure 1 (A) flows through the passage indicated by reference numeral 300 and exits from outlet 120. At this time, the oil is separated from the oil mist contained in the leaking gas in the impactor 140. Oil dripping from the impact plate 144 of the impactor 140 falls into the gap 146 of the impactor 140, flows along the gap 146 towards the short side of the base plate 130, and flows into the oil outlet region 152 of the oil discharge section 150 through the opening provided at the base plate 130. In existing oil mist separators, there is a situation where, when the flow rate of the leaking gas is high, there is a backflow of the leaking gas from the oil outlet of the oil discharge section 150, thereby spraying out the oil accumulated in the oil outlet region 152. This oil is entrained in the leaking gas and carried downstream, such as... Figure 1 As indicated by the arrow 400 in (A), in this embodiment, such entanglement is prevented or at least reduced by means of a cover structure 160 disposed above the drain port region 152.

[0044] When the leakage gas flow rate is high, some of the oil dripping from the impact plate 144 may overflow downstream through the opening in the impact plate 144. Furthermore, residual oil from the drain port area 152 may overflow, which the covering structure 160 cannot prevent. The oil overflow is blocked by the containment structure 170. The containment structure 170 not only blocks the oil separated by the impactor 140 but also blocks oil dripping from the bypass plate 210 of the cylinder head cover 200.

[0045] Oil that fails to be blocked by the containment structure 170 is carried to a more downstream side and is trapped in a stagnation that occurs in the wake of the multiple baffles 180. When a certain amount of oil accumulates in the stagnation, the oil that fails to be trapped overflows and is blocked by the oil storage section 182 provided on one side of the baffle 180.

[0046] When the leakage gas flow rate is low, the oil accumulated in the oil storage area of ​​the containment structure 170 flows into the oil outlet area 152 of the oil outlet section 150 through the opening of the impact plate 144 and the gap 146 of the impactor 140. When the leakage gas flow rate is low, the oil blocked by the oil storage section 182 flows into the oil outlet area 152 of the oil outlet section 150 through the return oil passage 190. As the oil flows along the return oil passage 190, it is distributed to the first surrounding outer return passage 192, the second surrounding outer return passage 194, and the surrounding inner return passage 196.

[0047] When the leakage gas flow rate is high, the separated oil is captured or blocked in stages by a plurality of structures consisting of a covering structure 160, a containment structure 170, a baffle plate 180, and an oil storage section 182. When the leakage gas flow rate is low, the separated oil is efficiently guided to the oil discharge port area 152 of the oil discharge section 150 by means of an oil return passage 190 consisting of a first outer return passage 192, a second outer return passage 194, and an inner return passage 196. This reduces or prevents oil from being carried away.

[0048] List of reference numerals

Claims

1. An oil mist separator for a PCV system of an internal combustion engine, the oil mist separator comprising: An inlet used to allow leaking gas to flow in. The exhaust port is used to discharge leaked gas. A base plate that forms a flow path for circulating leaking gas between the inlet and the outlet. An impactor for separating oil from leaking gas is mounted on the base plate. An oil drain section is disposed below the base plate, the oil drain section having an oil drain port area for receiving the separated oil, and Multiple baffles for capturing oil are formed on the upper surface of the base plate between the impactor and the outlet. The oil storage section for temporarily storing the oil captured by the baffle is partially disposed on at least one side of the plurality of baffles along the short side of the base plate.

2. The oil mist separator according to claim 1, wherein, An oil return passage connecting the oil storage section and the oil discharge section is also formed on the upper surface of the base plate.

3. The oil mist separator according to claim 1 or 2, wherein, The oil storage section is formed as a trough sloping towards the downstream side.

4. The oil mist separator according to claim 1 or 2, wherein, The impactor is composed of a perforated plate on the upstream side and an impact plate on the downstream side. A gap extending along the short side of the base plate is provided between the perforated plate and the impact plate, and the oil outlet area of ​​the oil discharge part is configured to be at least partially offset relative to the impactor along the short side of the base plate.

5. The oil mist separator according to claim 4, wherein, A containment structure for blocking the separated oil is provided between the impactor and the plurality of baffles.

6. The oil mist separator according to claim 5, wherein, The enclosure structure is integrally formed with the perforated plate and impact plate of the impactor.

7. The oil mist separator according to claim 5, wherein, A gap is provided at the enclosure structure, through which oil from the downstream side can circulate.

8. The oil mist separator according to claim 7 of claim 2, wherein, The oil return path is composed of a first outer return path, a second outer return path, and an inner return path. The first outer return path is defined by one sidewall of the enclosure structure in the short side direction of the base plate. The second outer return path is defined by another sidewall of the enclosure structure in the short side direction of the base plate. The inner return path passes through the inner side of the enclosure structure between the gap of the enclosure structure and the gap of the impactor.

9. The oil mist separator according to claim 1 or 2, wherein, The base plate is tilted such that its downstream side is higher than its upstream side.

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