Patent Publication Number: US-8974567-B2

Title: Rotating coalescer with keyed drive

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of and priority from Provisional U.S. Patent Application No. 61/383,787, filed Sep. 17, 2010, and Provisional U.S. Patent Application No. 61/383,793, filed Sep. 17, 2010. The present application is a continuation-in-part of U.S. patent application Ser. No. 12/969,742, filed Dec. 16, 2010, and U.S. patent application Ser. No. 12/969,755, filed Dec. 16, 2010. Each of the &#39;742 and &#39;755 applications 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, Provisional U.S. 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 of the above are incorporated herein by reference. 
    
    
     BACKGROUND AND SUMMARY 
     Parent Applications 
     The &#39;742 and &#39;755 parent applications relate 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 noted parent inventions 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. 
     Present Application 
     The present invention arose during continuing development efforts in gas-liquid separation technology, including the above noted technology, and including a rotating coalescer separating gas from a gas-liquid mixture, including air-oil and other gas-liquid mixtures. 
     In one embodiment, the present disclosure provides an authentication system ensuring that during maintenance servicing, the rotating coalescing filter element must be replaced only by an authorized replacement element, to ensure designated operation and performance, and that a nonauthorized aftermarket replacement element will not provide the noted designated operation and performance. In one embodiment, this ensures that an internal combustion engine being protected by a crankcase ventilation coalescer will receive at least the minimal level of protection from gas-borne contaminant that is necessary to achieve target levels for engine reliability and performance. 
     Applicant notes commonly owned co-pending U.S. patent application Ser. No. 13/167,814, filed on even date herewith, for another disclosure preventing use of a non-authorized replacement element during maintenance servicing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Parent Applications 
         FIGS. 1-21  are taken from the noted parent &#39;742 and &#39;755 applications. 
         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. 
       Present Application 
         FIG. 22  is a schematic sectional view of a coalescing filter assembly. 
         FIG. 23  is an exploded view of a portion of  FIG. 22 . 
         FIG. 24  is a top view of a component of  FIG. 23 . 
         FIG. 25  is like  FIG. 24  and shows another embodiment. 
         FIG. 26  is like  FIG. 24  and shows another embodiment. 
         FIG. 27  is like  FIG. 24  and shows another embodiment. 
         FIG. 28  is like  FIG. 24  and shows another embodiment. 
         FIG. 29  is like  FIG. 24  and shows another embodiment. 
         FIG. 30  is like  FIG. 24  and shows another embodiment. 
         FIG. 31  is a side view showing another embodiment of a portion of  FIG. 22 . 
         FIG. 32  is like  FIG. 23  and shows another embodiment. 
         FIG. 33  is an assembled view of the components of  FIG. 32 . 
         FIG. 34  is like  FIG. 23  and shows another embodiment. 
         FIG. 35  is like  FIG. 24  and shows another embodiment. 
         FIG. 36  is a view from below of a component of  FIG. 34 . 
         FIG. 37  is a top view of a component of  FIG. 34 . 
         FIG. 38  is an exploded view showing another embodiment. 
         FIG. 39  is like  FIG. 30  and shows another embodiment. 
         FIG. 40  is an exploded view showing another embodiment. 
         FIG. 41  is like  FIG. 32  and shows another embodiment. 
         FIG. 42  is an assembled view of the components of  FIG. 41 . 
         FIG. 43  is like  FIG. 42  and shows another embodiment. 
         FIG. 44  is like  FIG. 42  and shows another embodiment. 
         FIG. 45  is like  FIG. 41  and shows another embodiment. 
         FIG. 46  is an assembled view of the components of  FIG. 45 . 
         FIG. 47  is like  FIG. 41  and shows another embodiment. 
         FIG. 48  is an assembled view of the components of  FIG. 47 . 
         FIG. 49  is like  FIG. 41  and shows another embodiment. 
         FIG. 50  is an assembled view of the components of  FIG. 49 . 
         FIG. 51  is an exploded view showing another embodiment. 
         FIG. 52  is an exploded view showing another embodiment. 
         FIG. 53  is an exploded view showing another embodiment. 
         FIG. 54  is an exploded perspective view showing another embodiment. 
         FIG. 55  is a top view showing the components of  FIG. 54 . 
         FIG. 56  is a sectional assembly view taken along line  56 - 56  of  FIG. 55 . 
     
    
    
     DETAILED DESCRIPTION 
     Parent Applications 
     The following description of  FIGS. 1-21  is taken from commonly owned co-pending parent U.S. patent application Ser. No. 12/969,742, filed Dec. 16, 2010, which shares a common specification with commonly owned co-pending parent U.S. patent application Ser. No. 12/969,755, filed Dec. 16, 2010. 
       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 . An inlet port  38  supplies blowby gas  22  from crankcase  24  to hollow interior  32  as shown at arrows  40 . 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 flow-through, 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 not 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 coalescer 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. 
     Present Application 
       FIG. 22  shows a gas-liquid rotating coalescer  402  separating liquid from a gas-liquid mixture  404 . A coalescing filter assembly  406  includes a housing  408  closed by a lid  410  and having an inlet  412  receiving gas-liquid mixture  404 , a gas outlet  414  discharging separated gas as shown at dashed line arrow  416 , and a drain outlet  418  discharging separated liquid as shown at solid line arrow  420 . An annular rotating coalescing filter element  422  is provided in the housing, and a rotary drive member is provided, e.g. a rotary drive shaft  424 , or other rotary drive member, including as described above. A first set of one or more detent surfaces  426 ,  FIGS. 22-24 , are provided on the rotary drive member which may include a drive plate  428 . A second set of one or more detent surfaces  430  is provided on the coalescing filter element, e.g. on lower endcap  432  in the orientation shown. Other orientations are possible, e.g. a horizontal element axis. The second set of one or more detent surfaces  430  engagingly interacts with the first set of one or more detent surfaces  426  in interlocking mating keyed relation to effect rotation of the coalescing filter element by the rotary drive member. In one aspect, designated operation of the coalescer including designated rotation of coalescing filter element  422  requires that the coalescing filter element include the noted second set of one or more detent surfaces  430 , including engaged interaction with the first set of one or more detent surfaces  426  in interlocking mating keyed relation. This in turn ensures that only an authorized replacement coalescing filter element is used during maintenance servicing, and that a nonauthorized aftermarket replacement coalescing filter element missing the noted second set of one or more detent services will not effect the noted designated operation, e.g. a nonauthorized element will not rotate, or will not rotate smoothly at the proper speed of rotation, or will wobble, clatter, or vibrate undesirably, and so on. In various embodiments, the noted designated operation includes optimal and sub-optimal performance. 
     Coalescing filter element  422  rotates about an axis  434  and extends axially between first and second axial ends  436  and  438  and includes respective first and second axial endcaps  440  and  432 . Second axial endcap  432  has an axial endface  442  facing axially away from first axial end  436 . Second axial endcap  432  has a peripheral outer sideface  444  facing radially outwardly away from axis  434 . The noted second set of one or more detent surfaces is on at least one of endface  442  and outer sideface  444 . In the embodiment of  FIGS. 22-24 , the noted second set of one or more detent surfaces  430  is on endface  442 . Further in this embodiment, one of the noted first and second sets of detent surfaces, e.g. second set  430 , is provided by one or more raised axially protruding ridges  446 , including protrusions or the like, e.g. extending axially downwardly in  FIGS. 22-23 , and the other of the first and second sets of detent surfaces, e.g. first set  426 , is provided by one or more axially recessed slots  448 , including depressions or the like, e.g. recessed downwardly in  FIG. 23 , into the page in  FIG. 24 . Each slot  448  receives a respective ridge  446  inserted axially thereinto in nested relation providing the noted engaged interaction in interlocking mating keyed relation. In further embodiments, the first and second sets of one or more detent surfaces are provided by protrusions that mate. In the embodiment shown, the plurality of ridges and slots extend laterally as spokes radially outwardly from a hub  450  or other central region at axis  434 .  FIGS. 25-29  show further embodiments for the noted axially inserted nesting. One of the first and second sets of one or more detent surfaces, e.g. second set  430 , may be provided by a raised axially protruding protrusion member  452 ,  FIG. 25 , having an outer periphery having a keyed shape, e.g. a six pointed star in  FIG. 25 , a five pointed star protrusion member  454  in  FIG. 26 , a multi-pointed star or serrated shape protrusion member  456  in  FIG. 27 , a four pointed member such as rectangular shaped protrusion member  458  in  FIG. 28 , a three pointed triangular shaped protrusion member  460  in  FIG. 29 , a hexagon (not shown), etc. The other of the noted first and second sets of one or more detent surfaces, e.g. first set  426 , may be provided by an axially recessed pocket  462 , e.g. in drive plate  428  of rotary drive member  424 , which axially recessed pocket has an inner periphery having a reception shape complemental to the keyed shape of the respective protrusion member  452 ,  454 ,  456 ,  458 ,  460 , etc., and receiving the protrusion member inserted axially into the respective pocket such as  462  in keyed relation. In various embodiments, the noted keyed shape is characterized by a perimeter such as shown at  462  having a nonuniform radius from axis  434 . 
     In a further embodiment, the first set of one or more detent surfaces  426  may be provided by a first set of gear teeth  472 ,  FIG. 30 , on a rotary driven drive plate  474 , which set of gear teeth  472  may face axially toward second endcap  432 . The noted second set of one or more detent surfaces  430  may be provided by a second set of gear teeth  476 ,  FIGS. 31-33 , on endface  442  and facing axially away from the second endcap and engaging the first set of gear teeth  472  in driven relation. In another embodiment, the noted second set of one or more detent surfaces  430  are provided on outer sideface  444 , and the set of gear teeth  472 ,  FIG. 30 , face radially inwardly toward second endcap  432 . In this embodiment, the noted second set of one or more detent surfaces is provided by a second set of gear teeth on outer sideface  444  and facing radially outwardly away from second endcap  432  and engaging the noted first set of gear teeth in driven relation. 
     In a further embodiment,  FIGS. 34-37 , the rotary drive member is provided by a cam or pulley  482  driven by a belt or gear or otherwise as above, e.g.  FIGS. 1-5 , and provided in housing  484  closed by a lid  486  and containing rotating coalescing filter element  488 . Driven member  482  may have the noted first set of one or more detent surfaces, e.g. provided by axially recessed slots  490 ,  FIG. 35 , and lower endcap  492  of the coalescing filter element may have the noted second set of one or more detent surfaces  494 , e.g. as provided by the noted axially protruding ridges for insertion into slots  490 . The upper endcap  496  of the rotating coalescing filter element  488  may have a thrust button  498 ,  FIG. 37 , for axial insertion upwardly into pocket  500  of cover  486  for centered alignment and to provide thrust to create engagement pressure. 
     In a further embodiment,  FIG. 38 , coalescing filter element  502  rotates about axis  434  and extends axially along the axis between first and second axial ends having respective first and second axial endcaps  504  and  506 . The second endcap  506  has an axial endface  508  facing axially away from the noted first axial end. Second axial endcap  506  has a peripheral outer sideface  510  facing radially outwardly away from axis  434 . Second axial endcap  506  has an inner sideface  512  facing radially inwardly towards axis  434 . Inner sideface  512  is spaced radially outwardly of axis  434  and radially inwardly of outer sideface  510 . The noted second set of one or more detent surfaces  430  is provided on at least one of inner sideface  512 , endface  508 , and outer sideface  510 . In one embodiment, the noted second set of one or more detent surfaces is provided on inner sideface  512  at  514 . In one embodiment, the noted first set of one or more detent surfaces  426  is provided on a rotary drive member  516  as shown at  518  and engages the second set of one or more detent surfaces  514  on inner sideface  512  in bayonet relation, which may be a Tee hook and slot relation as shown at  520  in  FIG. 39 , or may be a single hook and side slot arrangement as shown at  522  in  FIG. 40 , or other known bayonet relation. Inner sideface  512  may form an axially recessed pocket  524  in second endcap  506 , wherein rotary drive member  516  extends axially into pocket  524 . 
     In further embodiments,  FIGS. 41-53 , one of the noted first and second sets of one or more detent surfaces is a pliable member such as  532  on the coalescing filter element endcap  432  and complementally pliably conforming to the other of the first and second sets of one or more detent surfaces, e.g.  FIGS. 42-44 ,  46 ,  48 ,  50 . The noted first and second sets of one or more detent surfaces engage each other in the noted interlocking mating keyed relation in a first engagement direction of rotation,  FIGS. 51-53 , and permit slippage in a second opposite direction of rotation. In other embodiments, slippage may occur in either direction or not at all. In further embodiments, a pliable member is additionally included on the rotary drive member plate  428 . 
     In a further embodiment,  FIGS. 54-56 , coalescing filter element  552  rotates about axis  434  and extends axially along the axis between first and second axial ends  554  and  556 ,  FIG. 56 , having respective first and second axial endcaps  558  and  560 . Coalescing filter element  552  has an axially extending hollow interior  562 . A torsional-resistance alignment coupler  564  extends axially between first and second endcaps  558  and  560  and maintains alignment thereof and prevents torsional twisting and wobble of coalescer filter element  552  therebetween, which may be desirable if the element is provided by coalescing filter media with little or no structural support therealong. 
     The noted first and second sets of one or more detent surfaces are provided in  FIGS. 54-56  by a rotary drive shaft  564  having an outer keyed profile, e.g. a hexagonal shape at  566 , and endcap  560  having a complemental inner periphery  568  of hexagonal shape. A third set of one or more detent surfaces  570  is provided on rotary drive member  564 , for example another hexagonal outer profile, which may or may not be a continuation of the profile from  566 . A fourth set of one or more detent surfaces  572  is provided on the coalescing filter element, for example at first endcap  558  at inner peripheral hexagonal surface  572 . The rotary drive member is provided by rotary drive shaft  564  extending through second axial endcap  560  and axially through hollow interior  562  and engaging first axial endcap  558 . The second set of one or more detent surfaces  568  is on second endcap  560 . The fourth set of one or more detent surfaces  572  is on first endcap  558 . The first and third sets of one or more detent surfaces  566  and  570  are on rotary drive shaft  564  at axially spaced locations therealong, e.g. as shown at  566  and  570 . The first and second sets of one or more detent surfaces  566  and  568  engage each other in interlocking mating keyed relation as rotary drive shaft  564  extends axially through second endcap  560 . Third and fourth sets of one or more detent surfaces  570  and  572  engage each other in interlocking mating keyed relation as rotary drive shaft  564  engages first endcap  558 . The axial extension of rotary drive shaft  564  through hollow interior  562  between the first and third sets of one or more detent surfaces  566  and  570  provides the noted respective engagement of second and fourth sets of one or more detent surfaces  568  and  572  on respective endcaps  560  and  558  and provides an alignment coupler extending axially between first and second endcaps  558  and  560  and maintaining alignment thereof and preventing torsional twisting of the coalescer filter element therebetween. In one embodiment, each of the noted first, second, third and fourth sets of one or more detent surfaces  566 ,  568 ,  570 ,  572  has a polygonal shape providing the noted engaged interaction in the noted interlocking mating keyed relation, and in one embodiment such polygonal shape is hexagonal. Other detent surface engagement in interlocking mating keyed relation may be provided. The noted detent surface may go through the element or may just form a pocket. For example, in one embodiment, lower endcap  560  is pierced, while the upper endcap  558  has a pocket. In other embodiments, the upper endcap is pierced. In further embodiments, the drive shaft only engages the lower endcap  560 , which lower endcap may be pierced for passage of the drive shaft therethrough, or such lower endcap may have a pocket for receiving the drive shaft without pass-through. In various embodiments, the pocket and/or protrusions face the element, and in others face away from the element. 
     First endcap  558  has a first set of a plurality of vanes  574  extending axially downwardly in  FIGS. 54 ,  56  into hollow interior  562  toward second endcap  560  and also extending radially outwardly from a first central hub  576  having an inner periphery  572  providing the noted fourth set of one or more detent surfaces. Second endcap  560  has a second set of a plurality of vanes  578  extending axially upwardly in  FIGS. 54 ,  56  into hollow interior  562  toward first endcap  558  and also extending radially outwardly from a second central hub  580  having an inner periphery  568  providing the noted second set of one or more detent surfaces. The first and second sets of vanes  574  and  578  extend axially towards each other and in one embodiment engage each other in hollow interior  562 . In one embodiment, the vanes of one of the noted sets, e.g. set  574 , have axially extending apertures  580  therein. In this embodiment, the vanes of the other of the sets, e.g. set  578 , have axially extending rods  582  which extend axially into apertures  580 . In various embodiments, vanes  574 ,  578  and/or rods  582 , apertures  580  are eliminated. 
     In various embodiments, the noted annular coalescer element is an inside-out flow coalescer element. The annular coalescer element has an annular shape selected from the group consisting of circular, oval, oblong, racetrack, pear, triangular, rectangular, and other closed-loop shapes. 
     In one embodiment, the disclosure provides a replacement coalescing filter element as above described, wherein designated operation of the coalescer including rotation of the coalescing filter element requires the noted second set of one or more detent surfaces, which in one embodiment may be at either axial end and/or may additionally include the noted fourth set of one or more detent surfaces, including the noted engaged interaction with the noted first set of one or more detent surfaces, which in one embodiment may additionally include the noted third set of one or more detent surfaces, in interlocking mating keyed relation, whereby a nonauthorized replacement coalescing filter element missing the noted second set of one or more detent surfaces, or the noted alternatives, will not effect the noted designated operation. This may be desirable to prevent the use of a nonauthorized aftermarket replacement coalescing filter element during maintenance servicing. 
     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.