GB1572664A - Crankcase emission fluid separator - Google Patents

Description

(54) A CRANKCASE EMISSION FLUID SEPARATOR (71) I, ELMER WALLACE BUSH, a citizen of the United States of America of 2010 Trimble Way, Sacramento, California, United States of America, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a crankcase emission separator. During the operation of an internal combustion engine a small portion of the air-fuel mixture inside the combustion chamber passes by the piston and piston rings into the crankcase just before combustion occurs. In like manner, exhaust fumes are forced past the piston rings into the crankcase just after combustion takes place. Collectively, these gases are termed blow-by, approximately 80% of which is unburned air-fuel mixture and 20% of which is a combustion product including water vapours, carbon dioxide and carbon monoxide.

Blow-by gases have always been a problem since, if they are allowed to remain in the crankcase, they form various deposits, acids and sludge, all of which are harmful to engine life and performance.

Traditionally, these fumes were vented to the atmosphere through a road draft tube.

In recent years, however, the smog problem has created a need for preventing crankcase vapours from discharging into the atmosphere. As a consequence, positive crankcase ventilation (PCV) systems have been developed which recycle the engine blow-by gases back into the air-fuel induction system of the engine, thence into the combustion chambers where the hydrocarbons can be burned.

In order to maintain combustion efficiency during idling, deceleration, acceleration and cruising, a flow control valve is interposed in the conduit conducting the blow-by gases from the crankcase to the intake manifold. The flow control valve, termed a PCV valve, is ordinarily modulated either by the extent of the pressure, or vacuum, in the crankcase or by the amount of vacuum in the intake manifold.

So long as the PCV valve works properly, the system serves its purpose in an effective manner. In fact, increased mileage is afforded by the return of unburned fuel to the combustion chambers of the engine.

Unfortunately, however, the PCV valve, which meters the flow of the crankcase emissions, often becomes clogged. When the valve sticks in one position, excessive air flow can unbalance the engine's air-fuel ratio, thus causing rough idling or even stalling. If the valve sticks in the other position, there is too little flow. In this situtation the fumes will not be carried off and the crankcase will become contaminated with sludge, acid, and other harmful products which lead to engine corrosion, poor lubrication and eventual serious engine damage if the valve is not cleaned or replaced.

Clogging of the PCV valve frequently occurs since the crankcase emissions not only comprise air and blow-by, both of which pass harmlessly through the valve, but also water in both liquid and vapour phase, resins, varnishes and acids, as well as products of a carbonaceous and calcareous nature, the latter having its source in lubrication additives. Solids, such as soot and various oxidation products, are also present and further tend to interfere with the operation of the PCV valve.

In order to maintain the PCV valve and engine in good operating condition, it is desirable to separate out and collect these harmful fractions found in the crankcase emissions while permitting the harmless unburned gaseous hydrocarbons and air to continue on through the PCV valve, thence to the intake manifold.

Various types of devices which remove at least some of the deleterious components found in crankcase emissions and which also allow the harmless fraction to pass through are already known. One such device is a crankcase emission liquid collector disclosed, for example, in U.S. Patent No.

3,250,062. In this patent, centrifuging and expansion are utilized to effect separation.

The aim of the invention is to provide a crankcase emission separator and collector which has at least some of the following properties: a) removes undesirable contaminants from crankcase emissions preferably prior to flow through the positive crankcase ventilation(PCV) valve installed pursuant to law on most internal combustion engines of motor vehicles, b) is compact in size, economical to purchase, easy to maintain, and readily installed, either at the factory or subsequently, c) enables the PCV valve to operate at maximum efficiency for a protracted period of time without replacement or cleaning, d) helps to maintain engine performance and efficiency at a desirable level and which can be used to advantage, not only in the engines of passenger vehicles but also in stationary engines, boats, trucks, fork lifts, and the like, and whether or not the engine includes a PCV valve, e) may be easily removed, cleaned and replaced, and f) can beneficially be utilized in conjunction with internal combustion engines of all kinds.

The invention provides a crankcase emission fluid separator for use with an internal combustion engine having a positively ventilated crankcase, an engine combustion air intake leading to a combustion chamber and a vacuum source, said separator conditioning the crankcase emissions and comprising a housing forming an enclosure in which conditioning of said emissions takes place, inlet means arranged for coupling to said engine crankcase for admitting the emissions therefrom to the interior of said housing, outlet means arranged for coupling to said engine combustion air intake for furnishing the conditioned emissions thereto from the interior of said housing, vacuum port means arranged for coupling a vacuum source to said separator, air intake means for introducing ambient air into said housing, fluid separating means within said housing which separates the liquid and solid components of the said emissions from the gaseous components thereof, said separating means forming a pervious barrier through which said emissions are caused to pass from said inlet means to said outlet means and which partitions said enclosure into an inlet zone communicating with said inlet means and an outlet zone communicating with said outlet means and comprising a container having first and second perforated walls and a plurality of relatively inert particles located in said container between said walls, a first conduit having a first end terminating within said inlet zone adjacent to a corresponding one of said perforated walls and a second end in fluid communication both with said inlet means and said air intake means, said vacuum port means including a valve for controlling the quantity of ambient air admitted via said air intake means to said first conduit in accordance with the magnitude of vacuum provided by said vacuum source, said valve including bias means for limiting the admission of ambient air into said first conduit to a minimum amount when the magnitude of said vacuum source is a minimum and for permitting the amount of ambient air admitted to said first conduit to increase as the magnitude of said vacuum source increases.

The invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure I is a representation of a typical installation, the scale of the separatorcollector being to a somewhat enlarged scale in comparison with the engine.

Figure 2 is a median vertical sectional view of the separator-collector to an enlarged scale, the plane of the section being indicated by the line 2-2 in Figure 1, showing the inlet port and auxiliary air intake structure, Figure 3 is a fragmentary vertical sectional view, to an enlarged scale, taken on the line 3-3 in Figure 1, showing the outlet port structure, and Figure 4 is a fragmentary vertical sectional view to an enlarged scale, taken on the line 4-4 in Figure 2, showing the auxiliary air intake structure.

While the crankcase emission separatorcollector according to the invention is susceptible of numerous physical embodiments, depending upon the environment and requirements of use, substantial numbers of the herein shown and described embodiments have been made, tested and used, and all have performed in an eminently satisfactory manner.

The illustrated crankcase emission separator and collector, generally designated by the reference numeral 11, is utilized e.g. in conjunction with an internal combustion engine 12 for a motor vehicle.

In customary fashion the engine includes an air filter 13 and carburettor 14 from which the air-fuel mixture emerges into an intake manifold 16 leading to a combustion chamber 17 of an engine cylinder 18.

In well-known manner, a small portion of the air-fuel mixture inside the combustion chamber 17 is forced past the piston rings 19 of the piston 21 just before and just after combustion takes place into the crankcase 22. These "blow-by" gases, as previously explained, consist of unburned air-fuel mixture and combustion products including water, carbon dioxide and carbon monoxide, and if allowed to remain in the crankcase 22 will form various types of sludge, varnish deposits, acids and other products deleterious to engine life and performance.

Prior to 1960, the blow-by gases were vented through a pipe into the atmosphere, forming the first one of the four sources of atmospheric pollutants, namely crankcase emissions, exhaust emission, particulates and evaporative losses, resulting from the operation of internal combustion engines.

Since 1960, positive crankcase ventilation (PCV) systems have been installed on most automotive engines in order to diminish or substantially eliminate crankcase emissions as a source of atmospheric pollutants. Such systems customarily utilize a first conduit 23 to lead fresh air from the air filter 13 into the crankcase 22, and a second conduit 24 to conduct the air plus blow-by mixture from the crankcase 22 to the air-fuel intake side of the engine.

The second conduit 24 includes a passageway 25 from the crankcase 22 to the rocker arm cover 26, and a hose 27 from the rocker arm cover 26 to the intake manifold 16.

Heretofore, the PCV valve 29 interposed in the second conduit 24 has often been mounted on the rocket arm cover 26 or placed in the hose 27 at a suitable location, and in most cases the PCV valve 29 is so constructed that at least a small amount of air plus blow-by is allowed to flow from the crankcase 22 to the intake manifold 16 under all conditions of engine operation, even at idling. Spring-biased plungers. diaphragms, or other flow-modulating components (not shown) are provided so that during acceleration, or cruising. a greater volume of gases is allowed to flow than during idling.

So long as the PCV valve 29 effects flow regulation in the desired fashion. the ventilation system is successful in performing its intended function. Clogging of the valve 29, however, adversely affects engine performance and as previously explained, can reduce engine life and cause other undesirable results.

In order to remove the deleterious liquid and solid contaminants which cause clogging and other harmful consequences but allow the scrubbed air plus blow-by fraction to continue through the PCV valve 29 and then into the intake manifold 16, the separator 11 according to the invention is preferably interposed in the second conduit 24 ahead of the PCV valve 29. Thus, as the crankcase emissions flow through the first portion 27a of the hose 27 extending from the rocker arm cover 26, the mixture of gases, liquids and solids enters a closure cap 30 or lid, suitably connected, as by a threaded collar 31 to a vessel 32. The lid 30 includes a bracket 33 which can be secured to an adjacent surface 34 such as the vehicle's fire wall, inner wall of a fender, or other location, as by fastenings 35.

The crankcase emissions arriving from the fhose portion 27a pass through a nipple 36 (Figure 2) in engagement with a threaded opening 37 in communication with a channel 38 leading to an inlet port 39 at the lower end of a vertical passageway 40.

As indicated diagrammatically by the arrow 41 in Figure 2, the crankcase emissions flowing through the channel 38 comprise: (1) undesirable liquid and solid components, indicated in solid black; (2) blowby gases, shown in dotted fashion; and (3) air introduced into the crankcase through a passageway 23, shown in Figure 1, the air being shown as white, or blank.

The crankcase emissions 41 are at a somewhat elevated temperature and pressure, under most conditions, and in order to begin the condensation process, a stream of relatively cool atmospheric air, as shown by the arrow 42 in Figure 2, is injected into the path of the crankcase emissions 41 as they enter the vertical passageway 40. The atmospheric air 42 enters through an auxiliary air intake device 43, as will subsequently be explained in detail.

The collision between the cooler air 42 and the warmer crankcase emissions 41, accompanied by the abrupt change in direction as the fumes turn the corner and flow down the passageway 40, is followed by a sudden expansion of the mixture as it emerges from the port 39.

As indicated by the arrows 46, the crankcase emission 41, diluted with cooler air 42 from the auxiliary air intake 43 flow axially downwardly along the axis 47 and radially outwardly. The expansion rate is so rapid that the process is substantially adiabatic, i.e. one in which there is no flow of heat into or out of the system. Since work is done by a mixture in adiabatic expansion, the temperature drops and in many instances a fog is observed inside the vessel 32 where the walls of the vessel are of transparent material.

The mixture 46 continues to expand axially and radially. The radial portion of the mixture 46 first passes through a fine mesh screen formed into a hollow, right circular cylinder 48. Encompassing and spaced radially from the inner cylinder 48 is an outer cylinder 49 also made from fine mesh screen.

The upper end of the inner cylinder 48 is flanged and secured, as by welding, to an upper circular disc 51 having an interiorly threaded boss 52 in threaded engagement with an exteriorly threaded stem 53 depending from the closure cover 30. The stem 53 is axially bored and forms the lower portion of the vertical passageway 40.

The lower end of the inner cylindrical screen 48 is likewise flanged and is secured to a lower circular disc 56.

The upper disc 51 and lower disc 56 likewise afford anchor points for the outer screen cylinder 49, the respective ends of which are flanged for additional strength and provide attachment points around the discs 51 and 56.

Disposed between the inner cylinder 48 and the outer cylinder 49 is a body of small discrete particles of relatively inert material, such as glass or fibreglass. A plurality of beads 61 having a diameter, for example, on the order of 3mm, or less and being of glass material. has been found to be very satisfactory as the aforesaid inert discrete particles.

It is clearly to be noted, however, that the particles are not limited to glass material or spherical shape, but can be of a fibrous stranded. interwoven or other configuration, or a combination of shapes.

As a mixture 46 continues to expand, it passes through the interstices of the glass beads 61, or equivalent, the glass particles affording a very large surface area and a myriad of tortuous channels through which the mixture travels. The discrete glass particles themselves undergo no change and yet separation of the liquid and solid contaminants from the gaseous blow-by and air mixture is effected. Whether the large surface area of the individual small particles causes separation by surface adsorption of the contaminants or whether the particles cause separation by a process analogous to catalysis is not as yet established.

It is clear, however. that when the blow by-air mixture emerges from the outer screen cylinder 49 and flows upwardly as indicated by the arrows 63, a high degree of separation, or'clarification", has occurred.

At the same time, the undesirable solid and liquid fractions drain downwardly from the glass particles 61, as shown by the arrows 64, and descend to form a sludge body 66 in the bottom of the vessel 32.

At periodic intervals, the vessel 32 is unscrewed from the cap 30 for cleaning.

As appears most clearly in Figure 3. the mixture 63 ascends, passes upwardly through the central opening in an annular gasket 67. or seal. and enters an outlet channel 68 formed in the elongated, radial boss 69 on top of the cover 30. The boss 69 is comparable to the elongated radial boss 71 in which the inlet channel 38 is located, the bosses 69 and 71 being angularly dislaced on the order of 45C (see Figure 1).

The mixture 63 enters a fitting 72 and then flows through a hose portion 27b to a PCV valve 29 which modulates flow rate in dependence upon engine operation. From the PCV valve 29, the blow by-air mixture continues through the hose portion 27h and enters the intake manifold 16 and thereafter the combustion chamber 17.

With particular reference to Figures 1. 2 and 4, it can be seen that the auxiliary air intake device 43 is located on top of the closure cap 39 and in fact, can be formed integrally therewith, if desired, although shown separately herein in the interests of greater clarity of disclosure.

The auxiliary air intake device 43 includes a horizontal, hollow, right circular cylinder 76 (Figures 3 and 4) provided with a bore 77 within which a plunger 78 translates between the "open" position shown in full line in Figure 4 and the "substantially closed" position shown in broken line in Figure 4.

At the right-hand end of the cylinder 76 (Figure 4), the bore 77 is provided with a fitting 81 connected to a tube 82 into which atmospheric air 42 enters through a suitable filter 83 (Figure 1).

Air flow from the tube 82 is controlled by movement of the plunger 78. When the plunger 78 is closed, the right hand end 85 of a stem 86 projecting from the plunger 78 substantially but not entirely covers and closes the opening 87 at the adjacent end of the fitting 81. Concurrently, when the end 85 of the stem 86 abuts the fitting 81, the plunger 78 almost but not entirely covers the exit port 88 of the right hand end of the bore 77.

In other words, the right hand end 85 of the plunger stem 86 has a plurality of notches 89 formed therein so that even when the end 85 abuts the fitting 81, a small amount of atmospheric air can bleed through the notches 89 and pass from the bore 77 down through a very small crack 90 when the plunger 78 substantially but not entirely covers the exit port 88.

A weak compression spring 91 is interposed between a threaded fitting 92 mounted on the left hand end of the cylinder 76 and the base of a blind hole 93 in the adjacent end of the plunger 78. The threaded fitting 92 is connected to a hose 94 extending to a T-fitting 95 (Figure 1) in the hose 96 leading from the carburettor 14 at a location above, or ahead of, the customary throttle plate, to a conventional vacuum advance unit 97 connected to the vehicle's distributor 98 (see Figure 1). It is clearly to be noted, however, that while the conventional vacuum advance mechanism on the distributor provides a convenient source of vacuum as a function of throttle opening, the auxiliary air device 43 can also be utilized where no distributor advance unit is available. Connection to another vacuum source, or operation by an electrically driven actuator controlled by a vacuum source is possible.

During idling, the throttle plate in the carburettor 14 is substantially closed, and very little. if any. vacuum exists in the ported vacuum advance system. In this mode. the spring 9 l urges the piston 78 toward closed" position and only a small amount of atmospheric air bleeds past the notches 89 adjacent the opening 87 in the fitting 81 and through the crack 90 into the channel 40.

However. when the vehicle is accelerated, or during cruising, the throttle plate in the carburettor 14 is open and vacuum exists in the ported vacuum advance system. A vacuum is thereby established in the connecting hose 94 and in the left hand end of the cylinder bore 77 in the vicinity of the compression spring 91. As a consequence, the differential pressure on the opposite ends of the piston 78 compresses the spring 91 and drives the piston 78 in a left-hand direction to the position shown in full line in Figure 4.

This allows a stream of fresh atmospheric air to flow through the air filter 83. pipe 82 and through the opening 87 into the right hand portion of the bore 77, thence down through the exit port 88. as indicated by the arrow 42. into the channel 40 where it collides with the inflowing crankcase emissions 41 (see Figures 2 and 4). Customarily.

the air filter 83 on the end of the pipe 82 is located under the vehicle's hood, at which position there is customarily at least a slight positive pressure resulting from car motion and fan operation. From the channel 40, the mixture 46 of crankcase emissions 41 and fresh air 4' descend, as previously explained, into the sleeve filter 60 where separation occurs as the mixture 46 expands and travels through the convoluted paths through the beads 61, the mixture being subjected to numerous collisions and numerous sudden changes of direction as myriad of beads is encountered. Extensive tests appear to support the theory that the combination of expansion, successive impacts and abrupt changes in flow paths as the mixture passes through the beads tends to strip the entrained solids and liquids from the gaseous fractions. The gases and light hydrocarbon vapours proceed through the separator whereas the heavier liquid and solid components undergo a change which retards them and allows them to flow or drip down into the sludge pool 66 for subsequent removal. The "dry" hydrocarbons and air pass harmlessly through the PCV valve and are conducted to the combustion chamber for improved engine performance and longer life.

WHAT WE CLAIM IS: 1. A crankcase emission fluid separator for use with an internal combustion engine having a positively ventilated crankcase, an engine combustion air intake leading to a combustion chamber and a vacuum source, said separator conditioning the crankcase emissions and comprising a housing forming an enclosure in which conditioning of said emissions takes place, inlet means arranged for coupling to said engine crankcase for admitting the emissions therefrom to the interior of said housing, outlet means arranged for coupling to said engine combustion air intake for furnishing the con ditioncd emissions thereto from the interior of said housing, vacuum port means arranged for coupling a vacuum source to said separator, air intake means for introducing ambient air into said housing, fluid separating means within said housing which separates the liquid and solid components of the said emissions from the gaseous components thereof, said separating means forming a pervious barrier through which said emissions are caused to pass from said inlet means to said outlet means and which partitions said enclosure into an inlet zone communicating with said inlet means and an outlet zone communicating with said outlet means and comprising a container having first and second perforated walls and a plurality of relatively inert particles located in said container between said walls, a first conduit having a first end terminating within said inlet zone adjacent to a corresponding one of said perforated walls and a second end in fluid communication both with said inlet means and said air intake means, said vacuum port means including a valve for controlling the quantity of ambient air admitted via said air intake means to said first conduit in accordance with the magnitude of vacuum provided by said vacuum source, said valve including bias means for limiting the admission of ambient air into said first conduit to a minimum amount when the magnitude of said vacuum source is a minimum and for permitting the amount of ambient air admitted to said first conduit to increase as the magnitude of said vacuum source increases.

2. A seperator according to Claim 1 wherein said perforated walls of the contain,er are cylindrical and define an interior space in communication with said first conduit and an outer annular region through which region said engine crankcase emissions are caused to pass radially outwards, and said container further includes first and second end wall members for enclosing said

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. distributor provides a convenient source of vacuum as a function of throttle opening, the auxiliary air device 43 can also be utilized where no distributor advance unit is available. Connection to another vacuum source, or operation by an electrically driven actuator controlled by a vacuum source is possible. During idling, the throttle plate in the carburettor 14 is substantially closed, and very little. if any. vacuum exists in the ported vacuum advance system. In this mode. the spring 9 l urges the piston 78 toward closed" position and only a small amount of atmospheric air bleeds past the notches 89 adjacent the opening 87 in the fitting 81 and through the crack 90 into the channel 40. However. when the vehicle is accelerated, or during cruising, the throttle plate in the carburettor 14 is open and vacuum exists in the ported vacuum advance system. A vacuum is thereby established in the connecting hose 94 and in the left hand end of the cylinder bore 77 in the vicinity of the compression spring 91. As a consequence, the differential pressure on the opposite ends of the piston 78 compresses the spring 91 and drives the piston 78 in a left-hand direction to the position shown in full line in Figure 4. This allows a stream of fresh atmospheric air to flow through the air filter 83. pipe 82 and through the opening 87 into the right hand portion of the bore 77, thence down through the exit port 88. as indicated by the arrow 42. into the channel 40 where it collides with the inflowing crankcase emissions 41 (see Figures 2 and 4). Customarily. the air filter 83 on the end of the pipe 82 is located under the vehicle's hood, at which position there is customarily at least a slight positive pressure resulting from car motion and fan operation. From the channel 40, the mixture 46 of crankcase emissions 41 and fresh air 4' descend, as previously explained, into the sleeve filter 60 where separation occurs as the mixture 46 expands and travels through the convoluted paths through the beads 61, the mixture being subjected to numerous collisions and numerous sudden changes of direction as myriad of beads is encountered. Extensive tests appear to support the theory that the combination of expansion, successive impacts and abrupt changes in flow paths as the mixture passes through the beads tends to strip the entrained solids and liquids from the gaseous fractions. The gases and light hydrocarbon vapours proceed through the separator whereas the heavier liquid and solid components undergo a change which retards them and allows them to flow or drip down into the sludge pool 66 for subsequent removal. The "dry" hydrocarbons and air pass harmlessly through the PCV valve and are conducted to the combustion chamber for improved engine performance and longer life. WHAT WE CLAIM IS:

1. A crankcase emission fluid separator for use with an internal combustion engine having a positively ventilated crankcase, an engine combustion air intake leading to a combustion chamber and a vacuum source, said separator conditioning the crankcase emissions and comprising a housing forming an enclosure in which conditioning of said emissions takes place, inlet means arranged for coupling to said engine crankcase for admitting the emissions therefrom to the interior of said housing, outlet means arranged for coupling to said engine combustion air intake for furnishing the con ditioncd emissions thereto from the interior of said housing, vacuum port means arranged for coupling a vacuum source to said separator, air intake means for introducing ambient air into said housing, fluid separating means within said housing which separates the liquid and solid components of the said emissions from the gaseous components thereof, said separating means forming a pervious barrier through which said emissions are caused to pass from said inlet means to said outlet means and which partitions said enclosure into an inlet zone communicating with said inlet means and an outlet zone communicating with said outlet means and comprising a container having first and second perforated walls and a plurality of relatively inert particles located in said container between said walls, a first conduit having a first end terminating within said inlet zone adjacent to a corresponding one of said perforated walls and a second end in fluid communication both with said inlet means and said air intake means, said vacuum port means including a valve for controlling the quantity of ambient air admitted via said air intake means to said first conduit in accordance with the magnitude of vacuum provided by said vacuum source, said valve including bias means for limiting the admission of ambient air into said first conduit to a minimum amount when the magnitude of said vacuum source is a minimum and for permitting the amount of ambient air admitted to said first conduit to increase as the magnitude of said vacuum source increases.

2. A seperator according to Claim 1 wherein said perforated walls of the contain,er are cylindrical and define an interior space in communication with said first conduit and an outer annular region through which region said engine crankcase emissions are caused to pass radially outwards, and said container further includes first and second end wall members for enclosing said

annular region and bounding at least one axial end of said interior space.

3. A separator according to Claim 1 or Claim 2 wherein said relatively inert particles are beads formed of glass or fibreglass.

4. A separator according to any preceding claim wherein said housing comprises a collecting vessel and a cap removably secured onto one end of said vessel. said inlet means includes an inlet port in said cap and a second conduit for connecting said inlet port with said crankcase. said outlet means includes an outlet port in said cap and a third conduit for connecting said outlet port and said engine combustion air intake, said vacuum port means including a fourth conduit for connecting said vacuum port means to said vacuum source. said valve comprising a hollow cylindrical member the interior of which communicates with said first conduit, said vacuum port means and also said air intake means via a passageway, and a piston slidable in said cylindrical member so as to substantially cover the said passageway when in a first position and uncover said passageway when in a second position, and said valve bias means includes a spring for urging said piston from its second position towards its first position, the urging force of the spring being overcome as the differential pressure acting on said piston exceeds a predetermined value and a vacuum is established in the cylindrical member on the end of said piston opposite from said passageway, and atmospheric air enters the other end of said cylindrical member via said passageway.

5. A separator according to Claim 4 wherein said collecting vessel is transparent.

6. A crankcase emission fluid separator substantially as described herein with reference to and as shown in the accompanying drawings.