Patent Publication Number: US-8968446-B1

Title: Oil and air separation system and method

Description:
FIELD OF THE DISCLOSURE 
     The invention relates generally to engine positive crankcase ventilation (PCV) systems and methods for recycling blow-by gases through a PCV valve into the engine&#39;s intake manifold, and more particularly in one exemplary embodiment, to systems and methods including an oil and air separator system for removal of crankcase oil from such blow-by gases. 
     BACKGROUND 
     In a combustion engine, blow-by gases typically include unburned gasoline. That is, an amount of air and unburned gasoline from the engine cylinder is pulled past the piston rings and into the crankcase. Instead of exhausting such blow-by gases to the atmosphere, a positive crankcase ventilation (PCV) system recycles the blow-by gases through a PCV valve into the engine&#39;s intake manifold. Such recycling occurs when the engine is operating at relatively slow speeds (e.g. idling), i.e., when the air pressure in the crankcase is higher than the air pressure in the intake manifold. 
     One problem associated with PCV systems and their use involves oil vapors. An engine&#39;s crankcase is used to store oil. A pan located below the crankshaft holds oil, and generally oil vapors from the oil in the pan may find their way into the blow-by gases. 
     It is undesirable for oil to be recycled with blow-by gases into an engine&#39;s intake manifold. Such oil may degrade engine performance by lowering the overall octane of the combustion mixture in a cylinder. Such oil also may coat the air intake and prevent airflow. 
     To combat the presence of oil in blow-by gases, oil and air separators were developed to remove the oil from the blow-by gases before recirculation into the intake manifold. There are various different models or types of oil and air separators available, one of which is shown by way of example in  FIG. 1 .  FIG. 1  describes one popular type of oil and air separators that involves passing oily blow-by gases through a filter material. The oil collects in droplets on the filter material, which is held in place by a screen. The oil is allowed to drop into the bottom of a can where the oil collects for later removal. 
     This “can approach” to oil and air separation, as shown by way of example in  FIG. 1 , is not without its drawbacks, however. In particular, the screen in the can that helps hold the filter material in place may serve as a pathway along which oil may flow. See  FIG. 1 . Thus, unwanted oil vapors may become present in the exhaust from the oil and air separator can. 
     SUMMARY 
     The present disclosure provides oil and air separation systems and methods. In one exemplary embodiment, an oil and air separation can includes: (i) a first screen that holds an oil filter assembly proximate a can intake for blow-by gases, and (ii) a second screen that holds an oil filter assembly proximate a can exhaust for blow-by gases, wherein the first screen and the second screen are spaced vertically apart from one another. 
     Other benefits and advantages of the present disclosure will be appreciated from the following detailed description. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross sectional view of a prior art oil and air separation can. 
         FIG. 2  is an exemplary embodiment of an oil and air separation can including, in one aspect, a first screen and a second screen spaced vertically apart from one another. 
         FIG. 3  is an exploded view of the exemplary embodiment of an oil and air separation can shown in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the invention and various alternatives are described. Those skilled in the art will recognize, given the teachings herein, that numerous alternatives and equivalents exist which do not depart from the invention. It is therefore intended that the invention not be limited by the description set forth herein or below. 
     One or more specific embodiments of the system and method will be described below. These described embodiments are only exemplary of the present disclosure. Additionally, in an effort to provide a concise description of these exemplary embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. 
     Further, for clarity and convenience only, and without limitation, the disclosure (including the drawings) sets forth exemplary representations of only certain aspects of events and/or circumstances related to this disclosure. Those skilled in the art will recognize, given the teachings herein, additional such aspects, events and/or circumstances related to this disclosure, e.g., additional elements of the devices described; events occurring related to oil and air separation and can use; etc. Such aspects related to this disclosure do not depart from the invention, and it is therefore intended that the invention not be limited by the certain aspects set forth of the events and circumstances related to this disclosure. 
     Turning now to the drawings,  FIG. 1  shows an exemplary prior art oil and air separation can  10 . Blow-by gas  20  enters the can  10  along with oil vapors  30  at intake port  40 . The gases  20  and  30  together are channeled through intake filter material  50 . Intake filter material  50  may consist of a stainless steel mesh. Oil from the oily vapors collects on the intake filter material  50 , and flows downward to screen  60 , e.g., due to gravity. Screen  60  holds the intake filter material  50  in place proximate the intake port  40 . Screen  60  also holds exhaust filter material  80  in place proximate the exhaust port  100 . One or more rubber o-rings  110  may be used to seal the various portions of the can  10  (i.e., the upper section  120 , the middle section  130 , and the lower section  140 , each removably joined to one or more other sections by threaded engagement). 
     Oil collects on the screen  60  and drips to form an oil pool  70  in the bottom of the can  10 . Oil also may migrate across the surface of the screen  60  and into the exhaust filter material  80 , as shown in  FIG. 1 . From there, blow-by gases  20 , as well as oily vapors  90  resulting at least in part from the oil migration across the surface of screen  60 , may exit the can  10  at exhaust port  100 . 
     The oil and air separation can embodiment shown in  FIG. 2  addresses the problems associated with the prior art embodiment of  FIG. 1 , by helping to reduce or eliminate the flow of oil outward through the can exhaust port. As shown in  FIG. 2 , a can  200  includes an upper portion  210 , a middle portion  220 , and a bottom portion  230 . The middle portion  220  at its upper end is removably coupled by threaded engagement to the lower end of upper portion  210 . The middle portion  220  at its lower end is removably coupled by threaded engagement to the upper end of bottom portion  230 . 
     The upper portion  210  includes a divider  240  that generally separates the volume defined by the upper portion  210  into a first intake side and a second exhaust side. A screen assembly  250  comprises a first screen portion  260  generally disposed on, and in fluid communication with, the intake side of upper portion  210 , and a second screen portion  270  generally disposed on, and in fluid communication with, the exhaust side of upper portion  210 . As shown in  FIG. 2 , the screen assembly  250  includes extension member  280 . Extension member  280  vertically spaces first screen portion  260  apart from second screen portion  270 . That is, while second screen portion  270  is generally disposed proximate the entrance to the second exhaust side of upper portion  210 , the first screen portion  260  is generally disposed within the volume defined by middle portion  220 . Thus, in one aspect, as compared to the prior art embodiment shown in  FIG. 1 , the extension member  280  in effect defines in part the first intake side and relocates the flow exit from the intake side of upper portion  210  from a first position proximate the lower end of upper portion  210  to a second position within the volume generally defined by middle portion  220 . 
     By vertically spacing first screen portion  260  to a position lower than second screen portion  270 , oil which collects on first screen portion  260  is inhibited from migration to second screen portion  270 . Thus, the amount of oil entering the exhaust side of upper portion  210  is substantially reduced or eliminated. 
     The operation of the can  200  involves blow-by gases  290  and oily vapors  300  entering the can  200  at intake port  310 . From there, the flow is directed through intake filter material  320 , which may include a stainless steel mesh or other suitable oil filtering assembly. Oil collects on the filter material  320  and flows downward to first screen portion  260 , e.g., due to gravity. From there, the oil is unable to migrate from first screen portion  260  to second screen portion  270 . Oil thus drops from first screen portion  260  (and from second screen portion  270 ) into an oil pool  330  that forms in the bottom portion  230  of can  200 . 
     Any oil vapors that are present in middle portion  220  of can  200  may be scrubbed of oil by exhaust filter material  340 . Thus, most if not all of the flow exiting the can  200  at exhaust port  350  comprises blow-by gas  290 . 
     O-rings, or another suitable sealing assembly  360 , may be used to seal the threaded connections between the various portions of can  200 . The volume defined by the middle portion  220  and the bottom portion  230  may be adjusted by varying the sizes of those components. In addition, one or more modular can extension portions may be added to the can  200 , each resembling middle portion  220 , so as to increase or otherwise adjust the overall can volume. It is believed that by increasing the volume of can  200 , less oil may enter the exhaust side of can upper portion  210  at second screen portion  270 . 
     In accordance with the description herein, a method of oil and air separation may include providing an oil and air separation can including a first screen that holds an oil filter proximate a can intake for blow-by gases and a second screen that holds an oil filter proximate a can exhaust for blow-by gases, wherein the first screen and the second screen are spaced vertically apart from one another. 
     Further, in accordance with the description herein, a method of oil and air separation may include providing a screen assembly including a first screen portion vertically spaced from a second screen portion, said screen assembly adapted for installation into an oil and air separator. In that way, prior art oil and air separators may be adapted to gain the advantages associated with the embodiments described herein. 
     It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art having the benefit of this disclosure, without departing from the invention. Accordingly, the invention is intended to embrace all such alternatives, modifications and variances. 
     Certain exemplary embodiments of the disclosure may be described. Of course, the embodiments may be modified in form and content, and are not exhaustive, i.e., additional aspects of the disclosure, as well as additional embodiments, will be understood and may be set forth in view of the description herein. Further, while the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention.