Claims:We claim:

1. A crankcase ventilation assembly configured to separate oil droplets from an air-oil mixture the crankcase ventilation assembly comprising:

a housing defining an interior chamber, and an air inlet, an air outlet and an oil drain outlet, all in fluid communication with the interior chamber;

a separator assembly disposed within the interior chamber and interpositioned between the air inlet and at least one of the air outlet and the oil drain outlet;

wherein:

the separator assembly comprises a plurality of separator baffles;

at least one of said separator baffles comprising a plurality of baffle members arranged in a configuration that defines one or more fluid paths through said separator baffle;

the plurality of baffle members comprising a first separator baffle member and a second separator baffle member positioned adjacent to each other, each of said first separator baffle member and second separator baffle member comprising a pair of half hexagon shaped channel elements conjoined in a sinuous configuration;

the adjacent first separator baffle member and second separator baffle member are arranged in a partially overlapping configuration that defines a fluid path between said first separator baffle member and said second separator baffle member; and

the defined fluid path between said first separator baffle member and said second separator baffle member includes an inlet end on an air inlet facing side of the at least one of said separator baffles and an outlet end on an air outlet facing side of the at least one of said separator baffles.

2. The crankcase ventilation assembly as claimed in claim 1, wherein the angle defined by the peak or trough of at least one of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member is an angle between 100o and 140o.

3. The crankcase ventilation assembly as claimed in claim 2, wherein the angle defined by the peak of one of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member is identical to the angle defined by the trough of the other of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member.

4. The crankcase ventilation assembly as claimed in claim 1, wherein inside surfaces of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member have surface irregularities formed thereon.

5. The crankcase ventilation system as claimed in claim 4, wherein the inside surfaces of the conjoined half hexagon shaped channel elements comprise one or more corrugated surfaces formed by said surface irregularities.

6. The crankcase ventilation system as claimed in claim 4, wherein the surface irregularities comprise grooves or channels formed on the inside surfaces of the conjoined half hexagon shaped channel elements.

7. A separator assembly configured to separate oil droplets from an air-oil mixture within a crankcase ventilation assembly that comprises a housing defining an interior chamber, and an air inlet, an air outlet and an oil drain outlet, all in fluid communication with the interior chamber, the separator assembly comprising:

a plurality of separator baffles, wherein

at least one of the separator baffles comprising a plurality of baffle members arranged in a configuration that defines one or more fluid paths through said separator baffle;

the plurality of baffle members comprising a first separator baffle member and a second separator baffle member positioned adjacent to each other, each of said first separator baffle member and second separator baffle member comprising a pair of half hexagon shaped channel elements conjoined in a sinuous configuration;

the adjacent first separator baffle member and second separator baffle member are arranged in a partially overlapping configuration that defines a fluid path between said first separator baffle member and said second separator baffle member; and

the defined fluid path between said first separator baffle member and said second separator baffle member includes an inlet end on an air inlet facing side of the at least one of the separator baffles and an outlet end on an air outlet facing side of the at least one of the separator baffles;

and wherein the separator assembly is disposed within the interior chamber and interpositioned between the air inlet and at least one of the air outlet and the oil drain outlet.

8. The separator assembly as claimed in claim 7, wherein the angle defined by the peak or trough of at least one of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member is an angle between 100o and 140o.

9. The separator assembly as claimed in claim 8, wherein the angle defined by the peak of one of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member is identical to the angle defined by the trough of the other of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member.

10. The separator assembly as claimed in claim 7, wherein inside surfaces of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member are provided have surface irregularities formed thereon.

11. The separator assembly as claimed in claim 10, wherein the inside surfaces of the conjoined half hexagon shaped channel elements comprise one or more corrugated surfaces formed by said surface irregularities.

12. The crankcase ventilation system as claimed in claim 11, wherein the surface irregularities comprise grooves or channels formed on the inside surfaces of the conjoined half hexagon shaped channel elements.

13. The separator assembly as claimed in claim 7, comprising a variable flow actuator positioned before the separator assembly, and configured to maintain fluid stream pressure upon the separator assembly within a predefined pressure range.
, Description:Field of the Invention

[001] The present invention relates to the field of combustion engines. Specifically, the invention relates to an inertial impactor capable of separating oil droplets from an oil-air mixture, and to engine crankcase ventilation systems incorporating said inertial impactor for use with an internal combustion engine.

Background

[002] A crankcase ventilation system provides a uni-directional passage for fluid or gases to escape in a controlled manner from the crankcase (i.e. the housing of the crankshaft) of an internal combustion engine. Crankcase ventilation has been found to be necessary, since internal combustion engines invariably involve a small but continual amount of “blow-by” i.e. escape of gases from the combustion caused by leakage past the piston rings and ending up inside the crankcase. The blow-by results in pressure build up within the crankcase. For eliminating pressure build up, a crankcase ventilation system is used to vent the crankcase.

[003] It has however been found that the rapidly moving parts and high oil pressures in engines results in a substantial degree of atomization of oil within the engine, and the formation of comparatively stable aerosols. The ventilation of crankcases in the usual manner therefore causes large losses of lubricating oil through dispersion in the form of this oil-air mixture.

[004] While prior art crankcase ventilation systems having oil-separation capabilities have been developed and used, such prior art systems suffer from multiple drawbacks including one or more of, high manufacturing costs, low oil-air separation efficiencies and / or unmanageably large engine footprint.

[005] It is an object of the invention to provide an efficient crankcase ventilation system with a small footprint that offers oil-separation efficiencies.

[006] It is additionally an object of the invention to develop an effective inertial impactor that optimizes separation of oil droplets from an air-oil mixture.

Summary

[007] The present invention provides a novel and inventive inertial impactor capable of separating oil droplets from an oil-air mixture, and provides novel and inventive engine crankcase ventilation systems incorporating said inertial impactor for use with an internal combustion engine.

[008] In an embodiment, the invention provides a crankcase ventilation assembly configured to separate oil droplets from an air-oil mixture. The crankcase ventilation assembly comprises a housing defining an interior chamber, and an air inlet, an air outlet and an oil drain outlet, all in fluid communication with the interior chamber. The crankcase ventilation assembly additionally comprises a separator assembly disposed within the interior chamber and interpositioned between the air inlet and at least one of the air outlet and the oil drain outlet.

[009] The separator assembly comprises a plurality of separator baffles. At least one of said separator baffles may comprise a plurality of baffle members arranged in a configuration that defines one or more fluid paths through said separator baffle.

[0010] The plurality of baffle members comprises a first separator baffle member and a second separator baffle member positioned adjacent to each other, each of said first separator baffle member and second separator baffle member comprising a pair of half hexagon shaped channel elements conjoined in a sinuous configuration.

[0011] The adjacent first separator baffle member and second separator baffle member may be arranged in a partially overlapping configuration that defines a fluid path between said first separator baffle member and said second separator baffle member – such that the defined fluid path between said first separator baffle member and said second separator baffle member includes an inlet end on an air inlet facing side of the at least one of said separator baffles and an outlet end on an air outlet facing side of the at least one of said separator baffles.

[0012] In an embodiment, the angle defined by the peak or trough of at least one of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member is an angle between 100o and 140o.

[0013] In a particular embodiment, the angle defined by the peak of one of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member is identical to the angle defined by the trough of the other of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member.

[0014] In a specific embodiment, inside surfaces of the conjoined half hexagon shaped channel elements within the first separator baffle member or the second separator baffle member have surface irregularities formed thereon. The inside surfaces of the conjoined half hexagon shaped channel elements may comprise one or more corrugated surfaces formed by said surface irregularities. The surface irregularities may comprise grooves or channels formed on the inside surfaces of the conjoined half hexagon shaped channel elements.

[0015] The invention additionally provides a separator assembly configured to separate oil droplets from an air-oil mixture within a crankcase ventilation assembly that comprises a housing defining an interior chamber, and an air inlet, an air outlet and an oil drain outlet, all in fluid communication with the interior chamber. The separator assembly may in various embodiments be configured in accordance with any of the exemplary embodiments already discussed hereinabove.

Brief Description of the Accompanying Drawings

[0016] Figure 1 illustrates a crankcase ventilation assembly.

[0017] Figure 2 illustrates a housing and a separator assembly.

[0018] Figures 3 and 4 illustrate features of a separator plate within the separator assembly.

[0019] Figure 5 illustrates a plurality of fluid passageways provided for within a crankcase case ventilation system of the present invention.

Detailed Description

[0020] Technologies for separating liquids and solids from gases can be broadly categorized as (i) gravity settling technologies (i.e. where the weight of the droplets or particles exceeds drag created by the flowing gas, (ii) centrifugal separation (i.e. where centrifugal force applied on droplets or particles exceeds the drag created by flowing gas, (iii) diffusional interception (i.e. where small aerosols collide with gas molecules, causing aerosols to deviate from the fluid flow path around barriers, increasing the likelihood of the aerosols striking a fiber surface and being removed) and (iv) inertial impaction, which occurs when a gas passes through a network of obstacles, such as fibers and impingement barriers – causing the gas to follow a tortuous path around the obstacles while the particles or liquid droplets tend to follow straight paths, impacting these obstacles and resulting in loss of velocity and / or coalescence, and consequent separation from the gas flow. The present invention relates to improvements in inertial impaction technology for separating aerosolized oil droplets from an air-oil mixture, and implementations of such inertial impaction technology in crankcase ventilation systems.

[0021] Figure 1 illustrates a crankcase ventilation assembly 100 in accordance with the present invention. Crankcase ventilation assembly 100 is configured to remove aerosolized oil droplets from blow-by gas escaping from the crankcase of a combustion engine. Crankcase ventilation assembly 100 comprises housing 110, said housing 110 defining an interior chamber 114 and comprising air inlet 102, air outlet 104, and oil drain outlet 106, each of which are in fluid communication with interior chamber 114, and further comprising separator assembly 108 disposed or formed within said interior chamber 114. Crankcase ventilation assembly 100 is configured such that separator assembly 108 is interpositioned between air inlet 102 on the one side and at least one (and in an embodiment both) of air outlet 104 and oil drain outlet 106 on the other side, such that a fluid path interconnecting air inlet 102 and at least one of (and preferably both of) air outlet 104 and oil drain outlet 106 passes through separator assembly 108. The crankcase ventilation assembly 100 is configured to separate oil from the blow-by gases passing through air inlet 102, and to discharge air (from which oil droplets have been removed) from air outlet 104, while discharging the separated oil from oil drain outlet 106.

[0022] The flow of blow-by gas escaping from the crankcase and through interior chamber 114 of the crankcase ventilation assembly 100 is achieved through fluid inlet 102. Air outlet 104 is configured to enable air (from which oil droplets have been removed) to be ventilated from said interior chamber 114 by virtue of a pipe, tube or other fluid path to any of the atmosphere, an engine exhaust system, or an air cleaner assembly (for example in a closed crankcase ventilation system).

[0023] Oil received at oil drain outlet 106 may be discharged from the crankcase ventilation system and back into the engine oil sump by virtue of a drain pipe, drain line or other fluid path formed between the oil drain outlet 106 and an oil sump.

[0024] Separator assembly 108 is, in an embodiment of the invention, an inertial separator assembly. The separator assembly 108 is interpositioned between the fluid path connecting air inlet 102 and air outlet 104 such that blow-by gas is forced to pass through the separator assembly 108 en route to air outlet 104. Additionally, the separator assembly 108 is configured so as to cause oil droplets in the blow-by gas to coalesce out of the gas fluid stream and to drain to a lower portion or a downwardly inclined surface 112 of the separator assembly and onward to oil drain outlet 106. By passing through separator assembly 108, the oil droplets are removed from the air-oil mixture and the resulting air fluidstream, continues through separator assembly housing 110 and out of air outlet 104.

[0025] As illustrated in Figure 1, separator assembly 108 comprises a plurality of separator baffles 108a to 108d which are serially positioned in a vertical orientation between air inlet 102 and air outlet 104. The serial configuration of the plurality of separator baffles 108a to 108d ensures that blow-by gases entering separator assembly 108 are forced to pass through each successive separator baffle 108a to 108d before exiting housing 110 through air outlet 104. While Figure 1 illustrates upto four separator baffles 108a to 108d, the separator assembly of the present invention may comprise one or more separator baffles. In an embodiment of the invention there is only a single separator baffle within separator assembly 108. In another embodiment, there are only two separator baffles within separator assembly 108.

[0026] Each separator baffle comprises a plurality of baffle members arranged in relation to each other in a configuration that defines one or more fluid paths through said separator baffle. Each such fluid path has an inlet end and an outlet end – wherein in passing through said separator baffle, the blow-by gases are forced to flow through said fluid paths, and wherein interaction (for example, impaction, drag or inertia) between the fluidstream and the surfaces of the fluid paths / fluid path walls that are defined by the baffle members, and / or changes in the direction of flow causes oil droplets to be deposited on said fluid path walls or baffle member surfaces, which deposited oil droplets coalesce with other oil droplets into larger droplets. The vertical orientation of each separator baffle further ensures that as oil droplets coalesce, gravity causes the coalesced droplets to drain towards the bottom of the separator assembly 108, while flow of the fluid stream through the fluid paths ensures that the oil-depleted blow-by gases pass through successive separator baffles and onward to air outlet 104.

[0027] The relatively large surface areas offered by serially arranged separator baffles within separator assembly 100 increases the cumulative surface area available for coalescing, and thereby increases the refining efficiency of the separator assembly 108.

[0028] Figure 2 illustrates a top transverse view of housing 110 – and more particularly of separator assembly 108 comprising a first separator baffle 208a and a second separator baffle 208b. In the illustration of Figure 2, separator baffle 208a is the separator baffle that is in closest proximity to air inlet 102 (i.e. the leading separator baffle), while separator baffle 208b is the separator baffle that is in closest proximity to air outlet 104 (i.e. the trailing separator baffle). While not illustrated in the embodiment of Figure 2, it would be understood that one or more additional separator baffles may be positioned as intermediate separator baffles between leading separator baffle 208a and trailing separator baffle 208b.

[0029] As illustrated in Figure 2, each separator baffle (for example separator baffle 208a) comprises a plurality of baffle members 210, 212 – each baffle member 210, 212 comprising a pair of half hexagon shaped vertical channel elements that are conjoined in a sinusoidal, sinuous or substantially s-shaped configuration. Each baffle member 210, 212 comprises a first four sided half hexagon shaped (or four sided half honeycomb structure shaped) vertically oriented channel element 214 and a second four sided half hexagonal shaped (or four sided half honeycomb structure shaped) vertically oriented channel element 216 – which first four sided half hexagonal shaped vertically oriented channel element 214 and second four sided half hexagonal shaped vertically oriented channel element 216 are conjoined into a sinuous configuration forming a first vertically oriented channel (formed by the walls of the first four sided half hexagonal shaped vertically oriented channel element 214) and a second vertically oriented channel (formed by the walls of the second four sided half hexagonal shaped vertically oriented channel element 216).

[0030] As illustrated in Figure 2, a separator baffle 208a comprises a plurality of baffle members 210, 212 (each baffle member comprising a conjoined pair of half hexagon shaped vertical channel elements), wherein adjacent pairs of baffle members 210, 212 within a separator baffle 208a are arranged in a serially interlocking configuration, where each adjacent pair of baffle members partially overlap each other. The partially overlapping configuration of adjacent pairs of baffle members is illustrated in more detail in Figure 3 – wherein baffle member 210 comprises a first four sided half hexagonal shaped vertically oriented channel 210a and a second four sided half hexagonal shaped vertically oriented channel 210b, and baffle member 212 comprises a first four sided half hexagonal channel 212a and a second four sided half hexagonal channel 212b – and wherein the adjacent baffle members 210 and 212 are arranged such that they partially overlap each other.

[0031] Figure 3 illustrates in more detail, separator baffle 208a exhibiting the partially overlapping configuration of baffle members 210 and 212. This partially overlapping configuration is achieved by (i) positioning a sidewall 210sw of baffle member element 210b (of first baffle member 210) such that said sidewall 210sw extends into a channel 212ch formed by baffle member element 212a (of second baffle member 212) and (ii) positioning a sidewall 212sw of baffle member element 212a such that said sidewall 212sw extends into a channel 210ch formed by baffle member element 210b (of first baffle member 210). It will be noted that baffle member element 210a (of first baffle member 210) and baffle member element 212b (of second baffle member 212) do not overlap with each other (i.e. sidewalls of each of said baffle member elements 210a, 212b do not extend into the channels respectively formed by the other of said baffle member elements 212b, 210a).

[0032] Simply put, the plurality of baffle members within a separator baffle may be arranged serially in a partially overlapping (or horizontally interlocking) configuration as shown in Figure 3 to form a separator baffle having tortuous fluid paths defined therethrough.

[0033] It would be understood that a separator baffle may comprise at least two (and possibly more than two) baffle members arranged in the serially overlapping configuration that is described and illustrated in Figure 3. Selection of the number of baffle members that are used to form the separator baffle is dependent on multiple factors, including the width of the fluid passageway across which the separator baffle is disposed, and also on the dimensions of the constituent baffle member. In an embodiment illustrated in Figure 3, in addition to the sinuous or s-shaped baffle members described above, a separator baffle 208a may include one or more four sided half hexagonal shaped single channel elements 220, 222 for ensuring the separator baffle structure extends all the way upto side walls 110a and 110b of housing 110.

[0034] In preferred embodiments of the invention, the peak or trough angle (ao, bo) (i.e. the angle forming the peak or the trough of any four sided half hexagonal shaped baffle member element, within any sinuous baffle member or within any four sided half hexagonal shaped single channel element within a separator baffle, is an angle between 100 o and 140o. In an embodiment a and b are identical.

[0035] It will be noted from the illustrations of Figures 2 and 3 that each sinuous baffle member of separator baffles 208a, 208b comprise a total of 7 sides formed in a shape approximating an angular S shape. The overlapping arrangement of adjacent sinuous baffle members serves to create zig-zag or tortuous fluid passageways leading from an air inlet facing side of each separator baffle to an air outlet facing side of said separator baffle. The oil-air mixture entering a fluid passageway formed by two overlapping sinuous baffle members will pass through said tortuous fluid passageways. In passing through said fluid passageways, oil droplets are deposited on the surfaces or walls of each four sided half hexagonal shaped channel element forming said baffle members, and thereafter coalesce on said surface, while the now oil-depleted air continues through the tortuous fluid passageways of the separator baffle. Oil coalescing on surfaces of each four sided half hexagonal shaped channel element flows towards the bottom of the separator baffle, from where the combined effect of gravity and / or a downward sloping inner surface 112 of housing 110 ensure that the accumulated oil droplets flow towards and out of oil drain outlet 106.

[0036] In an embodiment of the invention illustrated in Figure 4, walls of the baffle members may be provided with grooves or channels, or other surface irregularities on the inside surface of each four sided half heaxagon shaped vertically oriented channel element. In Figure 4, a sinuous baffle member is formed from a first four sided half hexagonal shaped vertically oriented channel element 402 and a second four sided half hexagonal shaped vertically oriented channel element 404. The inside surface of first four sided half hexagonal shaped vertically oriented channel element 402 is provided with a plurality of grooves formed by peaks 402a to 402d formed on the inside surface of said channel element. Likewise, the inside surface of second four sided half hexagonal shaped vertically oriented channel element 404 is provided with a plurality of grooves formed by peaks 404a to 404e on the inside surface of said channel element. The grooved configuration of the inside channel surfaces provide irregular surfaces to disrupt the flow of blow-by gas through the tortuous paths formed between adjacent sinuous bi-channel elements, resulting in increased inertial impaction and deposition of oil droplets (which have been removed from the air-oil mixture) on the inside surfaces of the baffle members.

[0037] It has been found that by forming a separator baffle using a plurality of sinuous baffle members in accordance with the above described embodiments, the coalescing effect on oil droplets in comparison to prior art separator assemblies improves significantly.

[0038] It has also been discovered that the maximum volumetric flow of fluid permitted by each separator baffle within the separator assembly can have a significant impact on the separation efficiency of the separator assembly.

[0039] In an embodiment of the invention, the crankcase ventilation assembly may include a variable flow actuator configured to vary or selectively open and close fluid paths through which blow by gases are directed onto the separator assembly. In an embodiment of the invention, the variable flow actuator may include a barrier plate interposed between fluid inlet 102 and separator assembly 108 of crankcase ventilation assembly 100. The barrier plate may include one or more apertures or nozzles that are capable of being actuated between at least an open position and a closed position or a partially closed position. The opening / closing of barrier plate apertures or nozzles may be responsive to one or more parameters, including in an exemplary embodiment, pressure exerted by A fluid stream is directed onto the barrier plate through fluid inlet 102.

[0040] In one embodiment, the barrier plate may include (i) a first set of open apertures that directs a fluidstream passing therethrough to a first set of openings / fluid passageways within separator baffles of separator assembly 108 and (ii) a second set of actuatably openable apertures that, when open, direct fluid passing therethrough to a second set of openings/fluid passageways within separator baffles of separator assembly 108, and which when closed form a barrier that prevents fluid from passing through the second set of openings/fluid passageways within separator baffles of separator assembly 108. In an embodiment of the invention, the second set of apertures opens in response to fluidstream pressure exceeding a predefined threshold.

[0041] Figure 5 illustrates a crankcase ventilation assembly having fluid inlet 102, fluid outlet 104 and drain outlet 106, and having a first fluid passageway 502 and a second fluid passageway 504 for directing an incoming fluidstream onto openings/fluid passageways within a separator assembly (not shown) within the crankcase ventilation assembly. By appropriately positioning a variable flow actuator of the type discussed above, one or both of fluid passageways 502 or 504 may be actuatably opened or closed by opening or closing apertures within said variable flow actuator – thereby enabling control over the specific fluid passageways (and the number of such fluid passageways) through which the fluidstream eventually passes. By implementing a variable flow actuator of the type discussed above within the crankcase ventilation system, the invention ensures that a minimum fluidstream pressure that is required by the separator assembly 108 for efficient separation of oil and air can be maintained, while at the same time ensuring that the fluidstream pressure does not build up to levels that could cause undesirable backpressure.

[0042] It would be understood that the various components of the crankcase ventilation system of the present invention may be manufactured using a variety of materials.

[0043] While exemplary embodiments of the present invention are described and illustrated herein, it will be appreciated that they are merely illustrative. It will be understood by those skilled in the art that various modifications in form and detail may be made therein without departing from or offending the spirit and scope of the invention as defined herein. Additionally, the invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not disclosed herein – and in particular embodiments specifically contemplated, is intended to be practiced in the absence of any element which is not disclosed herein.