Patent Publication Number: US-9885265-B2

Title: Crankcase ventilation inside-out flow rotating coalescer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Divisional of U.S. patent application Ser. No. 12/969,742, filed Dec. 16, 2010. U.S. patent application Ser. No. 12/969,742 claims the benefit of and priority from Provisional U.S. Patent Application No. 61/298,630, filed Jan. 27, 2010, Provisional U.S. Patent Application No. 61/298,635, filed Jan. 27, 2010, Provisional U.S. Patent Application No. 61/359,192, filed Jun. 28, 2010, Provisional U.S. Patent Application No. 61/383,787, filed Sep. 17, 2010, U.S. Patent Provisional Patent Application No. 61/383,790, filed Sep. 17, 2010, and Provisional U.S. Patent Application No. 61/383,793, filed Sep. 17, 2010, all incorporated herein by reference in their entirety. 
    
    
     BACKGROUND AND SUMMARY 
     The invention relates to internal combustion engine crankcase ventilation separators, particularly coalescers. 
     Internal combustion engine crankcase ventilation separators are known in the prior art. One type of separator uses inertial impaction air-oil separation for removing oil particles from the crankcase blowby gas or aerosol by accelerating the blowby gas stream to high velocities through nozzles or orifices and directing same against an impactor, causing a sharp directional change effecting the oil separation. Another type of separator uses coalescence in a coalescing filter for removing oil droplets. 
     The present invention arose during continuing development efforts in the latter noted air-oil separation technology, namely removal of oil from the crankcase blowby gas stream by coalescence using a coalescing filter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of a coalescing filter assembly. 
         FIG. 2  is a sectional view of another coalescing filter assembly. 
         FIG. 3  is like  FIG. 2  and shows another embodiment. 
         FIG. 4  is a sectional view of another coalescing filter assembly. 
         FIG. 5  is a schematic view illustrating operation of the assembly of  FIG. 4 . 
         FIG. 6  is a schematic system diagram illustrating an engine intake system. 
         FIG. 7  is a schematic diagram illustrating a control option for the system of  FIG. 6 . 
         FIG. 8  is a flow diagram illustrating an operational control for the system of  FIG. 6 . 
         FIG. 9  is like  FIG. 8  and shows another embodiment 
         FIG. 10  is a schematic sectional view show a coalescing filter assembly. 
         FIG. 11  is an enlarged view of a portion of  FIG. 10 . 
         FIG. 12  is a schematic sectional view of a coalescing filter assembly. 
         FIG. 13  is a schematic sectional view of a coalescing filter assembly. 
         FIG. 14  is a schematic sectional view of a coalescing filter assembly. 
         FIG. 15  is a schematic sectional view of a coalescing filter assembly. 
         FIG. 16  is a schematic sectional view of a coalescing filter assembly. 
         FIG. 17  is a schematic view of a coalescing filter assembly. 
         FIG. 18  is a schematic sectional view of a coalescing filter assembly. 
         FIG. 19  is a schematic diagram illustrating a control system. 
         FIG. 20  is a schematic diagram illustrating a control system. 
         FIG. 21  is a schematic diagram illustrating a control system. 
     
    
    
     DETAILED DESCRIPTION 
     The present application shares a common specification with commonly owned co-pending U.S. patent application Ser. No. 12/969,755, filed on even date herewith, and incorporated herein. 
       FIG. 1  shows an internal combustion engine crankcase ventilation rotating coalescer  20  separating air from oil in blowby gas  22  from engine crankcase  24 . A coalescing filter assembly  26  includes an annular rotating coalescing filter element  28  having an inner periphery  30  defining a hollow interior  32 , and an outer periphery  34  defining an exterior  36 . The annular rotating coalescing filter element  28  has axial end caps  29 ,  31 . An inlet port  38  supplies blowby gas  22  from crankcase  24  to hollow interior  32  as shown at arrows  40 . The axial end cap  29  is substantially sealed to the inlet port  38  such that, in at least one operating condition, little or no blowby gas bypasses the annular rotating coalescing filter element  28 . In one example. the inlet port  38  may be sealed to the coalescing filter assembly  26  and the axial end cap  29  may abut the coalescing filter assembly  26 . An outlet port  42  delivers cleaned separated air from the noted exterior zone  36  as shown at arrows  44 . The direction of blowby gas flow is inside-out, namely radially outwardly from hollow interior  32  to exterior  36  as shown at arrows  46 . Oil in the blowby gas is forced radially outwardly from inner periphery  30  by centrifugal force, to reduce clogging of the coalescing filter element  28  otherwise caused by oil sitting on inner periphery  30 . This also opens more area of the coalescing filter element to flow-through, whereby to reduce restriction and pressure drop, Centrifugal force drives oil radially outwardly from inner periphery  30  to outer periphery  34  to clear a greater volume of coalescing filter element  28  open to flowthrough, to increase coalescing capacity. Separated oil drains from outer periphery  34 . Drain port  48  communicates with exterior  36  and drains separated oil from outer periphery  34  as shown at arrow  50 , which oil may then be returned to the engine crankcase as shown at arrow  52  from drain  54 . 
     Centrifugal force pumps blowby gas from the crankcase to hollow interior  32 . The pumping of blowby gas from the crankcase to hollow interior  32  increases with increasing speed of rotation of coalescing filter element  28 . The increased pumping of blowby gas  22  from crankcase  24  to hollow interior  32  reduces restriction across coalescing filter element  28 . In one embodiment, a set of vanes may be provided in hollow interior  32  as shown in dashed line at  56 , enhancing the noted pumping. The noted centrifugal force creates a reduced pressure zone in hollow interior  32 , which reduced pressure zone sucks blowby gas  22  from crankcase  24 . 
     In one embodiment, coalescing filter element  28  is driven to rotate by a mechanical coupling to a component of the engine, e.g. axially extending shaft  58  connected to a gear or drive pulley of the engine. In another embodiment, coalescing filter element  28  is driven to rotate by a fluid motor, e.g. a pelton or turbine drive wheel  60 ,  FIG. 2 , driven by pumped pressurized oil from the engine oil pump  62  and returning same to engine crankcase sump  64 .  FIG. 2  uses like reference numerals from  FIG. 1  where appropriate to facilitate understanding. Separated cleaned air is supplied through pressure responsive valve  66  to outlet  68  which is an alternate outlet to that shown at  42  in  FIG. 1 . In another embodiment, coalescing filter element  28  is driven to rotate by an electric motor  70 ,  FIG. 3 , having a drive output rotary shaft  72  coupled to shaft  58 . In another embodiment, coalescing filter element  28  is driven to rotate by magnetic coupling to a component of the engine,  FIGS. 4, 5 . An engine driven rotating gear  74  has a plurality of magnets such as  76  spaced around the periphery thereof and magnetically coupling to a plurality of magnets  78  spaced around inner periphery  30  of the coalescing filter element such that as gear or driving wheel  74  rotates, magnets  76  move past,  FIG. 5 , and magnetically couple with magnets  78 , to in turn rotate the coalescing filter element as a driven member. In  FIG. 4 , separated cleaned air flows from exterior zone  36  through channel  80  to outlet  82 , which is an alternate cleaned air outlet to that shown at  42  in  FIG. 1 . The arrangement in  FIG. 5  provides a gearing-up effect to rotate the coalescing filter assembly at a greater rotational speed (higher angular velocity) than driving gear or wheel  74 , e.g. where it is desired to provide a higher rotational speed of the coalescing filter element. 
     Pressure drop across coalescing filter element  28  decreases with increasing rotational speed of the coalescing filter element. Oil saturation of coalescing filter element  28  decreases with increasing rotational speed of the coalescing filter element. Oil drains from outer periphery  34 , and the amount of oil drained increases with increasing rotational speed of coalescing filter element  28 . Oil particle settling velocity in coalescing filter element  28  acts in the same direction as the direction of air flow through the coalescing filter element. The noted same direction enhances capture and coalescence of oil particles by the coalescing filter element. 
     The system provides a method for separating air from oil in internal combustion engine crankcase ventilation blowby gas by introducing a G force in coalescing filter element  28  to cause increased gravitational settling in the coalescing filter element, to improve particle capture and coalescence of submicron oil particles by the coalescing filter element. The method includes providing an annular coalescing filter element  28 , rotating the coalescing filter element, and providing inside-out flow through the rotating coalescing filter element. 
     The system provides a method for reducing crankcase pressure in an internal combustion engine crankcase generating blowby gas. The method includes providing a crankcase ventilation system including a coalescing filter element  28  separating air from oil in the blowby gas, providing the coalescing filter element as an annular element having a hollow interior  32 , supplying the blowby gas to the hollow interior, and rotating the coalescing filter element to pump blowby gas out of crankcase  24  and into hollow interior  32  due to centrifugal force forcing the blowby gas to flow radially outwardly as shown at arrows  46  through coalescing filter element  28 , which pumping effects reduced pressure in crankcase  24 . 
     One type of internal combustion engine crankcase ventilation system provides open crankcase ventilation (OCV), wherein the cleaned air separated from the blowby gas is discharged to the atmosphere. Another type of internal combustion crankcase ventilation system involves closed crankcase ventilation (CCV), wherein the cleaned air separated from the blowby gas is returned to the engine, e.g. is returned to the combustion air intake system to be mixed with the incoming combustion air supplied to the engine. 
       FIG. 6  shows a closed crankcase ventilation (CCV) system  100  for an internal combustion engine  102  generating blowby gas  104  in a crankcase  106 . The system includes an air intake duct  108  supplying combustion air to the engine, and a return duct  110  having a first segment  112  supplying the blowby gas from the crankcase to air-oil coalescer  114  to clean the blowby gas by coalescing oil therefrom and outputting cleaned air at output  116 , which may be outlet  42  of  FIG. 1, 68  of  FIG. 2, 82  of  FIG. 4 . Return duct  110  includes a second segment  118  supplying the cleaned air from coalescer  114  to air intake duct  108  to join the combustion air being supplied to the engine. Coalescer  114  is variably controlled according to a given condition of the engine, to be described. 
     Coalescer  114  has a variable efficiency variably controlled according to a given condition of the engine. In one embodiment, coalescer  114  is a rotating coalescer, as above, and the speed of rotation of the coalescer is varied according to the given condition of the engine. In one embodiment, the given condition is engine speed. In one embodiment, the coalescer is driven to rotate by an electric motor, e.g.  70 ,  FIG. 3 . In one embodiment, the electric motor is a variable speed electric motor to vary the speed of rotation of the coalescer. In another embodiment, the coalescer is hydraulically driven to rotate, e.g.  FIG. 2 . In one embodiment, the speed of rotation of the coalescer is hydraulically varied. In this embodiment, the engine oil pump  62 ,  FIGS. 2, 7 , supplies pressurized oil through a plurality of parallel shut-off valves such as  120 ,  122 ,  124  which are controlled between closed and open or partially open states by the electronic control module (ECM)  126  of the engine, for flow through respective parallel orifices or nozzles  128 ,  130 ,  132  to controllably increase or decrease the amount of pressurized oil supplied against pelton or turbine wheel  60 , to in turn controllably vary the speed of rotation of shaft  58  and coalescing filter element  28 . 
     In one embodiment, a turbocharger system  140 ,  FIG. 6 , is provided for the internal combustion  102  generating blowby gas  104  in crankcase  106 . The system includes the noted air intake duct  108  having a first segment  142  supplying combustion air to a turbocharger  144 , and a second segment  146  supplying turbocharged combustion air from turbocharger  144  to engine  102 . Return duct  110  has the noted first segment  112  supplying the blowby gas  104  from crankcase  106  to air-oil coalescer  114  to clean the blowby gas by coalescing oil therefrom and outputting cleaned air at  116 . The return duct has the noted second segment  118  supplying cleaned air from coalescer  114  to first segment  142  of air intake duct  108  to join combustion air supplied to turbocharger  144 . Coalescer  114  is variably controlled according to a given condition of at least one of turbocharger  144  and engine  102 . In one embodiment, the given condition is a condition of the turbocharger. In a further embodiment, the coalescer is a rotating coalescer, as above, and the speed of rotation of the coalescer is varied according to turbocharger efficiency. In a further embodiment, the speed of rotation of the coalescer is varied according to turbocharger boost pressure. In a further embodiment, the speed of rotation of the coalescer is varied according to turbocharger boost ratio, which is the ratio of pressure at the turbocharger outlet versus pressure at the turbocharger inlet. In a further embodiment, the coalescer is driven to rotate by an electric motor, e.g.  70 ,  FIG. 3 . In a further embodiment, the electric motor is a variable speed electric motor to vary the speed of rotation of the coalescer. In another embodiment, the coalescer is hydraulically driven to rotate,  FIG. 2 . In a further embodiment, the speed of rotation of the coalescer is hydraulically varied,  FIG. 7 . 
     The system provides a method for improving turbocharger efficiency in a turbocharger system  140  for an internal combustion engine  102  generating blowby gas  104  in a crankcase  106 , the system having an air intake duct  108  having a first segment  142  supplying combustion air to a turbocharger  144 , and a second segment  146  supplying turbocharged combustion air from the turbocharger  144  to the engine  102 , and having a return duct  110  having a first segment  112  supplying the blowby gas  104  to air-oil coalescer  114  to clean the blowby gas by coalescing oil therefrom and outputting cleaned air at  116 , the return duct having a second segment  118  supplying the cleaned air from the coalescer  114  to the first segment  142  of the air intake duct to join combustion air supplied to turbocharger  144 . The method includes variably controlling coalescer  114  according to a given condition of at least one of turbocharger  144  and engine  102 . One embodiment variably controls coalescer  114  according to a given condition of turbocharger  144 . A further embodiment provides the coalescer as a rotating coalescer, as above, and varies the speed of rotation of the coalescer according to turbocharger efficiency. A further method varies the speed of rotation of coalescer  114  according to turbocharger boost pressure. A further embodiment varies the speed of rotation of coalescer  114  according to turbocharger boost ratio, which is the ratio of pressure at the turbocharger outlet versus pressure at the turbocharger inlet. 
       FIG. 8  shows a control scheme for CCV implementation. At step  160 , turbocharger efficiency is monitored, and if the turbo efficiency is ok as determined at step  162 , then rotor speed of the coalescing filter element is reduced at step  164 . If the turbocharger efficiency is not ok, then engine duty cycle is checked at step  166 , and if the engine duty cycle is severe then rotor speed is increased at step  168 , and if engine duty cycle is not severe then no action is taken as shown at step  170 . 
       FIG. 9  shows a control scheme for OCV implementation. Crankcase pressure is monitored at step  172 , and if it is ok as determined at step  174  then rotor speed is reduced at step  176 , and if not ok then ambient temperature is checked at step  178  and if less than 0° C., then at step  180  rotor speed is increased to a maximum to increase warm gas pumping and increase oil-water slinging. If ambient temperature is not less than 0° C., then engine idling is checked at step  182 , and if the engine is idling then at step  184  rotor speed is increased and maintained, and if the engine is not idling, then at step  186  rotor speed is increased to a maximum for five minutes. 
     The flow path through the coalescing filter assembly is from upstream to downstream, e.g. in  FIG. 1  from inlet port  38  to outlet port  42 , e.g. in  FIG. 2  from inlet port  38  to outlet port  68 , e.g. in  FIG. 10  from inlet port  190  to outlet port  192 . There is further provided in  FIG. 10  in combination a rotary cone stack separator  194  located in the flow path and separating air from oil in the blowby gas. Cone stack separators are known in the prior art. The direction of blowby gas flow through the rotating cone stack separator is inside-out, as shown at arrows  196 ,  FIGS. 10-12 . Rotating cone stack separator  194  is upstream of rotating coalescer filter element  198 . Rotating cone stack separator  194  is in hollow interior  200  of rotating coalescer filter element  198 . In  FIG. 12 , an annular shroud  202  is provided in hollow interior  200  and is located radially between rotating cone stack separator  194  and rotating coalescer filter element  198  such that shroud  202  is downstream of rotating cone stack separator  194  and upstream of rotating coalescer filter element  198  and such that shroud  202  provides a collection and drain surface  204  along which separated oil drains after separation by the rotating cone stack separator, which oil drains as shown at droplet  206  through drain hole  208 , which oil then joins the oil separated by coalescer  198  as shown at  210  and drains through main drain  212 . 
       FIG. 13  shows a further embodiment and uses like reference numerals from above where appropriate to facilitate understanding. Rotating cone stack separator  214  is downstream of rotating coalescer filter element  198 . The direction of flow through rotating cone stack separator  214  is inside-out. Rotating cone stack separator  214  is located radially outwardly of and circumscribes rotating coalescer filter element  198 . 
       FIG. 14  shows another embodiment and uses like reference numerals from above where appropriate to facilitate understanding. Rotating cone stack separator  216  is downstream of rotating coalescer filter element  198 . The direction of flow through rotating cone stack separator  216  is outside-in, as shown at arrows  218 . Rotating coalescer filter element  198  and rotating cone stack separator  216  rotate about a common axis  220  and are axially adjacent each other. Blowby gas flows radially outwardly through rotating coalesce filter element  198  as shown at arrows  222  then axially as shown at arrows  224  to rotating cone stack separator  216  then radially inwardly as shown at arrows  218  through rotating cone stack separator  216 . 
       FIG. 15  shows another embodiment and uses like reference numerals from above where appropriate to facilitate understanding. A second annular rotating coalescer filter element  230  is provided in the noted flow path from inlet  190  to outlet  192  and separates air from oil in the blowby gas. The direction of flow through second rotating coalescer filter element  230  is outside-in as shown at arrow  232 . Second rotating coalescer filter element  230  is downstream of first rotating coalescer element  198 . First and second rotating coalescer filter elements  198  and  230  rotate about a common axis  234  and are axially adjacent each other. Blowby gas flows radially outwardly as shown at arrow  222  through first rotating coalescer filter element  198  then axially as shown at arrow  236  to second rotating coalescer filter element  230  then radially inwardly as shown at arrow  232  through second rotating coalescer filter element  230 . 
     In various embodiments, the rotating cone stack separator may be perforated with a plurality of drain holes, e.g.  238 ,  FIG. 13 , allowing drainage therethrough of separated oil. 
       FIG. 16  shows another embodiment and uses like reference numerals from above where appropriate to facilitate understanding. An annular shroud  240  is provided along the exterior  242  of rotating coalescer filter element  198  and radially outwardly thereof and downstream thereof such that shroud  240  provides a collection and drain surface  244  along which separated oil drains as shown at droplets  246  after coalescence by rotating coalescer filter element  198 . Shroud  240  is a rotating shroud and may be part of the filter frame or end cap  248 . Shroud  240  circumscribes rotating coalescer filter element  198  and rotates about a common axis  250  therewith. Shroud  240  is conical and tapers along a conical taper relative to the noted axis. Shroud  240  has an inner surface at  244  radially facing rotating coalescer filter element  198  and spaced therefrom by a radial gap  252  which increases as the shroud extends axially downwardly and along the noted conical taper. Inner surface  244  may have ribs such as  254 ,  FIG. 17 , circumferentially spaced therearound and extending axially and along the noted conical taper and facing rotating coalescer filter element  198  and providing channeled drain paths such as  256  therealong guiding and draining separated oil flow therealong. Inner surface  244  extends axially downwardly along the noted conical taper from a first upper axial end  258  to a second lower axial end  260 . Second axial end  260  is radially spaced from rotating coalescer filter element  198  by a radial gap greater than the radial spacing of first axial end  258  from rotating coalescer filter element  198 . In a further embodiment, second axial end  260  has a scalloped lower edge  262 , also focusing and guiding oil drainage. 
       FIG. 18  shows a further embodiment and uses like reference numerals from above where appropriate to facilitate understanding. In lieu of lower inlet  190 ,  FIGS. 13-15 , an upper inlet port  270  is provided, and a pair of possible or alternate outlet ports are shown at  272  and  274 . Oil drainage through drain  212  may be provided through a one-way check valve such as  276  to drain hose  278 , for return to the engine crankcase, as above. 
     As above noted, the coalescer can be variably controlled according to a given condition, which may be a given condition of at least one of the engine, the turbocharger, and the coalescer. In one embodiment, the noted given condition is a given condition of the engine, as above noted. In another embodiment, the given condition is a given condition of the turbocharger, as above noted. In another embodiment, the given condition is a given condition of the coalescer. In a version of this embodiment, the noted given condition is pressure drop across the coalescer. In a version of this embodiment, the coalescer is a rotating coalescer, as above, and is driven at higher rotational speed when pressure drop across the coalescer is above a predetermined threshold, to prevent accumulation of oil on the coalescer, e.g. along the inner periphery thereof in the noted hollow interior, and to lower the noted pressure drop.  FIG. 19  shows a control scheme wherein the pressure drop, dP, across the rotating coalescer is sensed, and monitored by the ECM (engine control module), at step  290 , and then it is determined at step  292  whether dP is above a certain value at low engine RPM, and if not, then rotational speed of the coalescer is kept the same at step  294 , and if dP is above a certain value then the coalescer is rotated at a higher speed at step  296  until dP drops down to a certain point. The noted given condition is pressure drop across the coalescer, and the noted predetermined threshold is a predetermined pressure drop threshold. 
     In a further embodiment, the coalescer is an intermittently rotating coalescer having two modes of operation, and is in a first stationary mode when a given condition is below a predetermined threshold, and is in a second rotating mode when the given condition is above the predetermined threshold, with hysteresis if desired. The first stationary mode provides energy efficiency and reduction of parasitic energy loss. The second rotating mode provides enhanced separation efficiency removing oil from the air in the blowby gas. In one embodiment, the given condition is engine speed, and the predetermined threshold is a predetermined engine speed threshold. In another embodiment, the given condition is pressure drop across the coalescer, and the predetermined threshold is a predetermined pressure drop threshold. In another embodiment, the given condition is turbocharger efficiency, and the predetermined threshold is a predetermined turbocharger efficiency threshold. In a further version, the given condition is turbocharger boost pressure, and the predetermined threshold is a predetermined turbocharger boost pressure threshold. In a further version, the given condition is turbocharger boost ratio, and the predetermined threshold is a predetermined turbocharger boost ratio threshold, where, as above noted, turbocharger boost ratio is the ratio of pressure at the turbocharger outlet vs. pressure at the turbocharger inlet.  FIG. 20  shows a control scheme for an electrical version wherein engine RPM or coalescer pressure drop is sensed at step  298  and monitored by the ECM at step  300  and then at step  302  if the RPM or pressure is above a threshold then rotation of the coalescer is initiated at step  304 , and if the RPM or pressure is not above the threshold then the coalescer is left in the stationary mode at step  306 .  FIG. 21  shows a mechanical version and uses like reference numerals from above where appropriate to facilitate understanding. A check valve, spring or other mechanical component at step  308  senses RPM or pressure and the decision process is carried out at steps  302 ,  304 ,  306  as above. 
     The noted method for improving turbocharger efficiency includes variably controlling the coalescer according to a given condition of at least one of the turbocharger, the engine, and the coalescer. One embodiment variably controls the coalescer according to a given condition of the turbocharger. In one version, the coalescer is provided as a rotating coalescer, and the method includes varying the speed of rotation of the coalescer according to turbocharger efficiency, and in another embodiment according to turbocharger boost pressure, and in another embodiment according to turbocharger boost ratio, as above noted. A further embodiment variably controls the coalescer according to a given condition of the engine, and in a further embodiment according to engine speed. In a further version, the coalescer is provided as a rotating coalescer, and the method involves varying the speed of rotation of the coalescer according to engine speed. A further embodiment variably controls the coalescer according to a given condition of the coalescer, and in a further version according to pressure drop across the coalescer. In a further version, the coalescer is provided as a rotating coalescer, and the method involves varying the speed of rotation of the coalescer according to pressure drop across the coalescer. A further embodiment involves intermittently rotating the coalescer to have two modes of operation including a first stationary mode and a second rotating mode, as above. 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be inferred therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. The different configurations, systems, and method steps described herein may be used alone or in combination with other configurations, systems and method steps. It is to be expected that various equivalents, alternatives and modifications are possible within the scope of the appended claims. Each limitation in the appended claims is intended to invoke interpretation under 35 U.S.C. §112, sixth paragraph, only if the terms “means for” or “step for” are explicitly recited in the respective limitation.