Patent Publication Number: US-9890671-B2

Title: Crankcase ventilation system having an oil jet pump with an integrated check valve

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. national stage application claiming the benefit of International Application No. PCT/US2014/065901, filed on Nov. 17, 2014, which claims priority to U.S. Provisional Patent Application No. 61/962,875, entitled “CRANKCASE VENTILATION SYSTEM HAVING AN OIL JET PUMP WITH AN INTEGRATED CHECK VALVE,” filed on Nov. 18, 2013. The entire contents of these applications are incorporated herein by reference in their entirety and for all purposes. 
    
    
     TECHNICAL FIELD 
     This present application relates to crankcase ventilation (“CV”) systems for internal combustion engines. More particularly, the present application relates to a jet pump having an integrated check valve that prevents the flow of engine oil into a crankcase ventilation filter of the CV system under cold engine operating conditions. 
     BACKGROUND 
     During the combustion cycle of conventional internal combustion engines, some combustion gases may leak past the piston rings of the cylinder and into the crankcase. These leaked gases are often referred to as blow-by gases. Crankcase ventilation (“CV”) systems are employed to vent the blow-by gases from the crankcase. Some CV systems are open loop systems, meaning the blow-by gases are vented to the ambient environment. Other CV systems are closed loop systems, meaning the blow-by gases are returned to the engine for combustion. 
     Many CV systems include a crankcase ventilation filter that allows the blow-by gases to be swept out of the crankcase (e.g., out of a road draft tube, into the engine intake, etc.). The crankcase ventilation filter may be a coalescing filter, a ventilation rotating filter, a coalescer, an inertial separator or the like. The crankcase ventilation filter may assist in treating the blow-by gases to reduce environmental impact of the internal combustion engine. In some situations, oil contained in the crankcase may backtrack into the crankcase ventilation filter. Backtracked oil may damage the CV system and/or the engine if it enters and remains in the crankcase ventilation filter. Accordingly, the crankcase ventilation filter may include a drain chamber to route any backtracked oil back to the engine or crankcase. However, in some engines, oil contained in the crankcase is at a higher pressure than the oil in the crankcase ventilation filter drain. Thus, the oil in the crankcase ventilation filter drain may need to be pumped back into the engine or crankcase to overcome the pressure differential. 
     Some CV systems utilize an oil jet pump to help drain separated oil in the drain chamber of the crankcase ventilation filter back to the crankcase. Pressurized oil is forced through a nozzle, which creates a high-velocity stream of engine oil that is directed towards a mixing bore of the oil driven jet-pump in the CV system. The mixing bore is arranged adjacent to the crankcase ventilation filter drain along a conduit routing oil back to the engine or crankcase. The high-velocity stream of oil leaving the nozzle and entering the mixing bore creates shear forces on the oil in the drain chamber. The shear forces draw the oil from the crankcase ventilation filter drain into the conduit routing oil back to the engine or crankcase thereby creating a pumping effect. 
     However, under cold engine conditions, the oil may be too viscous to form the required high-velocity stream that creates the necessary shear forces to draw oil from the crankcase ventilation filter drain to the conduit routing the oil back to the engine or crankcase. The high viscosity may be the result of the oil&#39;s low temperature caused by a cold engine condition. Additionally, under cold engine conditions, the pressurized oil may flow into the crankcase ventilation filter drain and potentially damage the crankcase ventilation filter and or cause oil loss due to increased oil consumption. 
     SUMMARY 
     One embodiment relates to a crankcase ventilation system including a crankcase ventilation filter configured to vent blow-by gases from a crankcase. A crankcase ventilation filter drain is coupled to the crankcase ventilation filter, wherein the crankcase ventilation filter drain is configured to collect oil that enters the crankcase ventilation filter and to return the collected oil to the crankcase. The system includes a pressurized oil supply, as well as a nozzle coupled to the pressurized oil supply and configured to form an oil jet adjacent to an exit of the crankcase ventilation filter drain. A valve is coupled to the crankcase ventilation filter drain, wherein the valve is configured to prevent pressurized oil supply back-tracking and entering the crankcase ventilation filter through an opening that connects the crankcase ventilation filter drain to the crankcase ventilation filter housing. When a temperature of the pressurized oil is above a threshold temperature, the oil jet draws the collected oil out of the filter drain to the exit back into the crankcase. When the temperature of the pressurized oil is below the threshold temperature, the oil jet does not draw the collected oil out of the crankcase ventilation filter drain and oil from the pressurized oil supply backtracks into the crankcase ventilation filter drain. 
     Another embodiment relates to a lubrication system for an internal combustion engine having a crankcase. The lubrication system includes a crankcase ventilation filter drain configured to provide oil separated from crankcase blow-by gases. The separated oil is at a lower pressure than oil in the internal combustion engine. A mixing bore is in fluid communication with the crankcase ventilation filter drain and a pressurized oil supply. A nozzle is in fluid communication with the pressurized oil supply. The nozzle directs a pressurized flow of oil into the mixing bore such that the pressurized flow of oil draws the separated oil from the crankcase ventilation filter drain into a component of the internal combustion engine. A valve is coupled to the crankcase ventilation filter drain. The valve is configured to prevent the separated oil from flowing back into the crankcase. 
     These and other features, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a cross-sectional view of a portion of CV system for a lubrication system of an internal combustion engine is shown according to an exemplary embodiment. 
         FIG. 2  is a cross-sectional view showing lubrication oil flowing at a first velocity through a nozzle of the portion of the CV system of  FIG. 1 . 
         FIG. 3  is a cross-sectional view showing lubrication oil flowing at a second velocity through the nozzle of the portion of the CV system of  FIG. 1 . 
         FIG. 4  is a graph of oil flow rate of the CV system of  FIG. 1  versus temperature. 
         FIG. 5  is a cross-sectional view of a check valve of the CV system in a closed position is shown according to an exemplary embodiment. 
         FIG. 6  is a cross-sectional view of the check valve of  FIG. 5  in an open position. 
         FIG. 7  is a cross-sectional view of a CV system for a lubrication system of an internal combustion engine according to an exemplary embodiment. 
         FIG. 8  is a cross-sectional view of a check valve of a CV system shown according to an exemplary embodiment 
     
    
    
     DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS 
     Referring to the figures generally, the various embodiments disclosed herein relate to a crankcase ventilation (“CV”) system having a check valve in combination with a pump (e.g., an oil jet pump). The check valve allows for temporary choking or restricting the backflow of engine oil into the CV system crankcase ventilation filter from the engine under cold operating conditions. When the check valve is closed (i.e., choking the backflow of oil into the crankcase ventilation filter), the crankcase ventilation filter&#39;s continuous drainage functionality may be reduced. After the engine oil warms up to a threshold temperature, the engine oil becomes thin enough to form a high-velocity stream (e.g., less viscous than at a lower temperature) as the oil passes through a nozzle of the CV system. The high-velocity stream creates necessary shear forces to draw engine oil out of the crankcase ventilation filter and back into the crankcase or the engine. Once the necessary shear forces are created, the check valve opens to allow for normal crankcase ventilation filter drain operation. 
     Referring to  FIG. 1 , a cross-sectional view of a portion of CV system  100  for a lubrication system of an internal combustion engine is shown according to an exemplary embodiment. The lubrication system circulates engine lubrication oil (e.g., 15W40 motor oil), shown as pressurized oil  102 , to the various components of the internal combustion engine. The oil  102  may be circulated through the engine by a pump. As shown in  FIG. 1 , the CV system  100  includes a supply of pressurized oil  102  that flows through a nozzle  104 . The nozzle  104  may create a high-velocity stream of engine oil that is directed towards a mixing bore  106  of the CV system  100 . After leaving the nozzle  104 , the oil  102  then enters a mixing bore  106 . In some arrangements, the diameter of the mixing bore  106  can range between 1.2 to 3 times the diameter of the nozzle  104 . After passing through the mixing bore  106 , the oil is routed back to the components of the engine (e.g., back to the crankcase). The velocity of the stream is at least partially dependent on the viscosity of the oil  102 . Accordingly, as the temperature of the oil  102  increases (e.g., from engine operation), the oil  102  becomes less viscous and the velocity of stream exiting the nozzle  104  increases. The nozzle  104  may be a motive jet nozzle. 
     During operation of the internal combustion engine, some combustion blow-by gases may leak past the piston rings of the cylinder and into the crankcase of the engine. The blow-by gases may be removed from the crankcase through the CV system  100 . The CV system  100  includes a crankcase ventilation filter (inertial separator, static and dynamic coalescing CV filters, etc.). The crankcase ventilation filter may be coalescing filter, a ventilation rotating filter, a coalescer, an inertial separator, or the like. The crankcase ventilation filter is configured to vent blow-by gases from the crankcase. In some situations, oil contained in the crankcase may backtrack into the crankcase ventilation filter and or the CV housing. Accordingly, the crankcase ventilation filter includes a crankcase ventilation filter drain  108  to provide the backtracked oil back to the engine or the crankcase. The oil in the crankcase ventilation filter drain  108  may be a first pressure and the oil in the crankcase or the engine may be at a second pressure, wherein the first pressure is lower than the second pressure. Accordingly, the oil contained in the crankcase ventilation filter drain  108  will not naturally flow back into the engine or crankcase (e.g., via gravity). The oil contained in the crankcase ventilation filter drain  108  may be drawn or pumped across the pressure differential and back into the engine or crankcase. 
     Referring again to  FIG. 1 , the crankcase ventilation filter drain  108  configured to collect backtracked oil and to drain the collected oil downstream of the nozzle  104  (i.e., after the nozzle  104  in a flow direction of the oil leaving the nozzle  104 ). The crankcase ventilation filter drain  108  may provide the collected oil to the mixing bore of the lubrication system. The diameter of the crankcase ventilation filter drain  108  may be at least three times the diameter of the nozzle  104 . The outlet or exit of the crankcase ventilation filter drain  108  may be adjacent to the nozzle  104 . Accordingly, when a high-velocity stream of lubrication oil is exiting the nozzle  104  towards a mixing bore  106 , the high-velocity stream of lubrication oil creates shear forces on the oil collected in the crankcase ventilation filter drain  108 . The shear forces draw the collected oil from the crankcase ventilation filter drain  108  into the mixing bore  106  and back to the engine or the crankcase. 
     Referring to  FIG. 2 , a first cross-sectional view showing lubrication oil flowing through the portion of the CV system  100  of  FIG. 1  is shown. As shown in  FIG. 2 , a high-velocity stream  202  of lubrication oil that is formed by the nozzle  104  and is directed towards the mixing bore  106 . The oil flowing through the nozzle  104  is thin enough to form a high-velocity stream  202 . For example, the oil may be 15W40 oil at sixty degrees Celsius. The high-velocity stream  202  of oil from the nozzle  104  and through the mixing bore  106  creates shear forces on the oil contained in the crankcase ventilation filter drain  108 . The shear forces on the oil contained in the crankcase ventilation filter drain  108  draw the oil contained in the crankcase ventilation filter drain  108  from the crankcase ventilation filter drain  108  and into the mixing bore  106 . In effect, the high-velocity stream  202  pumps the oil contained in the crankcase ventilation filter drain  108  from the low pressure within the crankcase ventilation filter drain  108  to a high pressure within the crankcase. The flow of oil from the crankcase ventilation filter drain  108  to the mixing bore  106  may be referred to as a scavenge flow. 
     Referring to  FIG. 3 , a second cross-sectional view showing lubrication oil flowing through the portion of the CV system  100  of  FIG. 1  is shown. The oil flow of  FIG. 3  is exemplary of a backflow condition in which oil flows up the crankcase ventilation filter drain  108  and away from the mixing bore  106 . The oil flowing through the nozzle  104  is more viscous than the oil flowing through the nozzle  104  in  FIG. 2 . This may be caused by cold engine conditions (e.g., when an engine first starts up, cold weather, etc.). For example, the oil may be 15W40 oil at zero degrees Celsius. Since the oil is more viscous than the oil in  FIG. 2 , the oil does not form a high-velocity stream (as shown in  FIG. 2 ) when passing through the nozzle  104 . When the high-velocity stream is not formed, the shear forces created on the oil contained in the crankcase ventilation filter drain  108  are not great enough to draw the collected oil from the crankcase ventilation filter drain  108  into the mixing bore  106 . As shown by the flow arrows, the oil leaving the nozzle  104  may flow from the higher pressure of the mixing bore  106  to the lower pressure of the crankcase ventilation filter drain  108 . 
     Referring to  FIG. 4 , a graph  400  of oil flow rate of the CV system of  FIG. 1  versus temperature is shown. The graph charts both the oil flow rate through the nozzle  104  (“motive” flow rate  402 ) and the oil flow rate through the crankcase ventilation filter drain  108  (“scavenge” flow rate  404 ). As shown in the graph, as temperature of the oil increases, the motive flow rate  402  generally increases. The motive flow rate  402  increases because the oil becomes less viscous as the oil temperature increases. Under cold engine conditions, the scavenge flow rate  404  is negative, meaning that the oil flows into and through the crankcase ventilation filter drain  108  and away from the mixing bore  106  (e.g., as shown in  FIG. 3 ). As the temperature of the oil crosses the threshold temperature  406 , the scavenge flow rate  404  becomes positive, meaning that the oil flows through the crankcase ventilation filter drain  108  and into the mixing bore  106  (e.g., as shown in  FIG. 2 ). 
     Referring to  FIG. 5 , a cross-sectional view of a check valve  500  of the CV system is shown according to an exemplary embodiment. The check valve  500  of  FIG. 5  is shown in the closed position, meaning the valve prevents the flow of oil out of an opening  504  in the crankcase ventilation filter drain  108  (e.g., an opening in the valve cap) and into the crankcase ventilation filter  502 . A protective screen or filter (not shown) may be placed over the opening  504 . As noted above with respect to  FIG. 3 , during cold engine conditions, the oil pressure differential forces oil up through the crankcase ventilation filter drain  108  and away from the mixing bore  106 . If the backflow of oil completely fills the crankcase ventilation filter drain  108  and/or the crankcase ventilation filter  502 , sludge may be deposited in the crankcase ventilation filter  502 . The sludge may damage the crankcase ventilation filter  502 , which may in turn damage the engine. Accordingly, the check valve  500  closes when the oil flows into the crankcase ventilation filter drain  108 , thereby choking the flow of oil through the crankcase ventilation filter drain  108  and preventing the flow of oil into the crankcase ventilation filter  502 . 
     The check valve  500  is closed when the ball  506  is pressed against the opening  504 . The ball  506  is comprised of a material that is of a lower density than the oil. The ball  506  may be hollow or solid. The ball  506  is of a larger diameter than the opening  504  of the crankcase ventilation filter drain  108 . Accordingly, as the oil flows into the crankcase ventilation filter drain  108 , the oil lifts the ball  506  into place against the opening to the crankcase ventilation filter drain  108 . The opening  504  and the ball  506  have mating shapes such that when the ball  506  is pressed against the opening  504  by the backflow of oil, the backflow of oil is prevented from exiting the crankcase ventilation filter drain  108  through the opening  504 . The opening  504  may be chamfered or domed to prevent the ball  506  from sticking in the opening  504  and increased operational angularity capabilities. 
     Referring to  FIG. 6 , a cross-sectional view of the check valve  500  of  FIG. 5  in an open position. As the engine begins to warm and as the oil heats up, the oil&#39;s viscosity reduces (e.g., as shown above in  FIG. 4 ). As the oil&#39;s viscosity reduces, a high-velocity jet of oil flowing through the nozzle  104  forms, and the shear forces on the oil in the crankcase ventilation filter drain  108  begin to draw the oil out of the crankcase ventilation filter drain  108 . As the oil leaves the crankcase ventilation filter drain  108 , the ball  506  floats away from the opening  504  in the crankcase ventilation filter drain  108  (i.e., gravity pulls the ball  506  down away from the opening). In some arrangements the ambient air pressure on the other side of the opening may force the ball  506  away from the opening  504 . When the oil level within the crankcase ventilation filter drain  108  falls below a threshold, the ball  506  rests on standoffs  602  in a non-floating position. The standoffs  602  may be supports, ribs, machined pockets, cavities, or the like. The standoffs  602  prevent choking off of the backflow oil out of the crankcase ventilation filter drain  108 . 
     Although the check valve  500  of  FIG. 5  and  FIG. 6  utilizes a ball  506 , alternative arrangements of the check valve may utilize a disc or a flap. In such an arrangement, the disc or flap functions with the same basic principles of the ball  506 . The disc or flap prevents the backflow of oil through the crankcase ventilation filter drain  108  and into the crankcase ventilation filter  502  by blocking the opening  504  when the scavenge flow rate is negative. The disc or flap allows the oil in the crankcase ventilation filter drain  108  to leave the crankcase ventilation filter drain  108  when the scavenge flow rate is positive. The disc or flap may or may not be comprised of a material having a lower density than the oil used by the internal combustion engine. Guides may be formed in the crankcase ventilation filter drain to prevent the disc or flap from sticking in the closed position. 
     Referring to  FIG. 7 , a check valve and oil pump combination  700  is shown according to an alternative embodiment. Unlike the check valve and oil pump combination discussed above with respect to  FIGS. 1-6 , the pump (i.e., the high-velocity stream of oil) is arranged in a horizontal fashion as opposed to a vertical fashion. Accordingly, the ball  702  (or disc or flapper) moves in a direction that is perpendicular to the high-velocity jet of oil generated by the nozzle  704 . The general operation of the check valve and oil pump combination  700  of  FIG. 7  is substantially the same as the general operation of the check valve and oil pump combination of  FIGS. 1-6 . 
     Referring to  FIG. 8 , a cross-sectional view of a check valve of a CV system  800  shown according to an exemplary embodiment. The check valve of  FIG. 8  is similar to the check valve shown in  FIG. 5  and  FIG. 6 . As shown in  FIG. 8 , a protective screen  802  is positioned over the check valve opening. 
     The above described check valve and oil pump combinations for use with CV systems may be used with stationary and dynamic crankcase ventilation filters. The check valve may be integrated with the pump component or may be separate components attached with fasteners. 
     As utilized herein, the terms “approximately,” “about,” “substantially,” and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims. 
     It should be noted that the term “exemplary” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples). 
     The terms “coupled,” “connected,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. 
     References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” etc.) are merely used to describe the orientation of various elements in the FIGURES. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. 
     It is important to note that the construction and arrangement of the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.