Abstract:
A diesel engine crankcase ventilation filter has a flat low profile modular filter housing, preferably extending vertically and having a top opening closed by a modular filter element inserted downwardly thereinto and closing and completing the housing. The construction provides a closed crankcase ventilation, CCV, filter in mobile diesel engine applications of limited space.

Description:
BACKGROUND AND SUMMARY 
     The invention relates to closed crankcase ventilation, CCV, filters for diesel engines. 
     Diesel engines have crankcase vents to relieve pressure buildup in the engine. A frequent cause of pressure buildup in the engine is from air leaking past the piston rings into the crankcase. The air that is vented out of the crankcase, also known as blow-by gas or crankcase gas, contains soot and oil mist particles. For many years, the blow-by gas along with the oil and soot was vented to atmosphere through a “road tube” to direct the flow to a desired area such as the ground, or away from specific engine parts. In recent years, metal mesh filters have been used to try and remove some of the larger oil droplets from the blow-by stream. These have had mixed results in the field. There have also been aftermarket products which remove oil mist and soot from engine blow-by gas. These products have been designed for industrial and stationary applications, and are usually too large and bulky for mobile applications. 
     Over the past few years, for appearance and environmental reasons, there has been motivation to eliminate the “road tube” type of design, and close the crankcase ventilation system. Closing the crankcase ventilation system means returning the blow-by gas back to the incoming combustion air stream to the engine, for example, at the air cleaner, turbocharger, intake manifold, or other engine intake. If a closed crankcase system is used, aerosol-sized droplets and soots, which for the most part are ignored in an open system, should be removed. This is desired in a closed system in order to avoid adverse effects on various engine components, especially the turbocharger and aftercooler. To do this, a degree of filtration beyond metal mesh is desired. 
     Packaging a closed crankcase ventilation system in a diesel engine compartment is a problem because of limited space. The closed crankcase ventilation, CCV, system requires routing hoses from the crankcase vent on the engine to the CCV housing, and from the CCV housing to either the dirty side of the air filter or to the turbo inlet of the diesel engine. Furthermore, a drain line needs to be run from the CCV housing back to the oil sump. A “stand alone” CCV system will have certain envelope requirements. For example, in a mid-range diesel engine, e.g. 150 to 300 horsepower, a projected envelope size would be a cylindrical housing of about four inches outer diameter and six to seven inches long plus room for connecting hoses, drain lines and valves. In mobile diesel engine applications, finding this amount of space in a convenient location is a problem. 
     The invention of commonly owned copending U.S. patent application Ser. No. 09/387,819, filed Sep. 1, 1999, provides a diesel engine crankcase ventilation filter addressing and solving the above-noted packaging and space problem, including the provision of a flat low profile crankcase ventilation filter, and enabling mounting of the flat low profile filter housing directly on the diesel engine valve cover in a horizontal orientation, with minimum space requirements and minimum plumbing requirements. 
     The present invention provides another solution to the noted packaging and space problem. The present invention provides a modular flat low profile crankcase ventilation filter and housing, and in preferred form enabling mounting in a vertical orientation. In a desirable aspect, the invention enables a modular housing construction provided by a pair of clamshell housing halves having a top opening closed by a modular filter element inserted downwardly thereinto and closing and completing the housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a diesel engine crankcase ventilation filter in accordance with the invention. 
     FIG. 2 is a disassembled exploded perspective view of the assembly of FIG.  1 . 
     FIG. 3 is a disassembled exploded perspective view of a portion of FIG.  1 . 
     FIG. 4 is a partial sectional view taken along line  4 — 4  of FIG.  2 . 
     FIG. 5 is a sectional view taken along line  5 — 5  of FIG.  6 . 
     FIG. 6 is a sectional view taken along line  6 — 6  of FIG.  1 . 
     FIG. 7 is a sectional view taken along line  7 — 7  of FIG.  6 . 
     FIG. 8 is a sectional view taken along line  8 — 8  of FIG.  7 . 
     FIG. 9 is a sectional view taken along line  9 — 9  of FIG.  1 . 
     FIG. 10 is an enlarged view of a portion of FIG.  9 . 
     FIG. 11 is an exploded perspective view of the assembly of FIG.  1 . 
     FIG. 12 is like FIG.  11  and shows another embodiment. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a closed crankcase ventilation, CCV, filter  20  for a diesel engine  22 . The filter has a flat low profile vertically extending modular filter housing  24  having an inlet  26  receiving oil and air from the crankcase  28  of the diesel engine, and having an outlet  30  returning air to the diesel engine at engine intake  32  such as the clean side or the dirty side of the air filter, the turbo charger inlet, the intake manifold, or other engine intake. A flat panel coalescing filter element  34 , FIG. 2, extends vertically in the housing and has a first vertical side  36 , FIGS. 2,  7 , receiving the oil and air from inlet  26 , FIG. 6, and separating the oil from the air, and having a second vertical side  38  passing air to outlet  30 . In the orientation of FIG. 7, the oil and air flow from right to left through the filter element, with the oil mist, soot and particles coalescing in the filter. Flat panel filter element  34  is provided by coalescing filter media  40  sandwiched between outer wire mesh screens  42  and  44 . Housing  24  extends vertically as shown at directional projection line  46 , FIG. 1, between a top end  48  and a bottom end  50 . The housing extends longitudinally as shown at directional projection line  52  between first and second distally opposite ends  54  and  56 . Flat panel filter element  34  extends vertically and longitudinally in the housing. The oil falls by gravity and drips vertically along vertically extending flat panel filter element  34 . The housing has a lower drain  58 , FIGS. 2,  7 ,  8 , discharging separated oil back to the engine oil sump through fitting  60  as shown at  62 . 
     Housing  24  has a first vertically and longitudinally extending flat plenum  64 , FIGS. 2,  7 ,  6 , facing first side  36  of filter element  34 . Oil and air from inlet  26  flow through the first plenum as shown at arrows  66  in FIG.  6 . The housing has a second vertically and longitudinally extending flat plenum  68 , FIGS. 2,  7 ,  6 , facing second side  38  of filter element  34 . Air flows through second plenum  68 , as shown at arrows  70  in FIG. 6, to outlet  30 . The vertical and longitudinal extent of first plenum  64  is substantially the same as the vertical and longitudinal extent of first side  36  of filter element  34 . The vertical and longitudinal extent of second plenum  68  is substantially the same as the vertical and longitudinal extent of second side  38  of the filter element. The vertical and longitudinal extent of plenums  64  and  68  are substantially the same. 
     Housing  24  has a vertically extending first filter mount guide channel  72 , FIGS. 2,  6 , and a vertically extending second filter mount guide channel  74 . The guide channels engage and locate filter element  34  such that the filter element extends vertically in the housing and is located laterally between plenums  64  and  68 . Housing  24  has a longitudinally extending lower filter mount guide channel  76 , FIGS. 2,  7 , engaging and locating filter element  34 . Each of the guide channels  72 ,  74 ,  76  preferably engages a respective sealing gasket  78 ,  80 ,  82  on the filter element to seal plenum  64  from plenum  68 . Sealing gaskets  78 ,  80 ,  82  are provided on respective end caps  84 ,  86 ,  88 , FIG. 1, of the filter element. 
     Housing  24  has a top opening  90 , FIG. 11, receiving filter element  34  such that the filter element may be inserted downwardly into the housing. The filter element has a top end  92  with a top closure plate  94  sealingly attached thereto, by adhesive bonding, sonic welding, or other attachment. Filter element  34  and top closure plate  94  form an integral replaceable modular unit. As the filter element is inserted downwardly into housing  24  through open end  90 , top closure plate  94  engages housing  24  and closes opening  90  and first and second plenums  64  and  68 . Top closure plate  94  is sealed to the housing by a gasket around opening  94  including longitudinally extending gasket sections  96 ,  98 , FIG. 7, and laterally extending gasket sections  100 , FIG. 5,  102 , FIG.  11 . Filter element  34  is sealed at vertical end  84  by gasket  78  in guide channel  72 . Filter element  34  is sealed at its lower horizontal longitudinal end  88  by gasket  82  in lower guide channel  76 . Filter element  34  is sealed at its vertical end  86  by gasket  80  in guide channel  74 . Filter element  34  is sealed at its top end  92  by closure plate  94  which in turn is sealed by the noted gaskets  96 ,  98 ,  100 ,  102  in housing opening  90 . 
     Housing  24  is provided by a pair of clamshell halves  104 ,  106 , FIG. 2, having the noted top opening  90  in assembled condition, FIG.  11 . Alternatively, housing  24  is a single unitary member. Top closure plate  94  of the filter element mates with the clamshell halves, or a single unitary housing, and closes top opening  90  such that top closure plate  94  of filter element  34  completes the housing, including if the housing is formed by the clamshell halves. The clamshell halves are plastic members and are held together by flexible snap fit tabs  108 ,  110 ,  112 ,  114 , FIGS. 2,  9 ,  10 . Top closure plate  94  is a plastic member and has a pair of flexible downwardly extending side tabs  116 ,  118  engaging respective clamshell halves  104 ,  106  in snap fit relation. Other attachment mechanisms may be used for the clamshell halves and/or the top closure plate, for example, screws such as  120 , FIG.  12 . 
     Housing  24  has a bypass port  122 , FIGS. 2,  4 , communicating with inlet  26 . A bypass valve  124 , FIG. 5, in the bypass port has a normally closed position, which is the position illustrated in FIG. 5, such that air and oil from inlet  26  flow to filter element  34 . Bypass valve  124  has a pressure actuated open position passing the air and oil therethrough as an alternate path as shown at  126 , preferably back to atmosphere or to the engine intake. Bypass valve  124  is actuated to the open position in response to an overpressure condition in plenum  64  corresponding to a predetermined pressure drop across filter element  34 , to ensure venting of the engine crankcase even if filter element  34  becomes plugged. Bypass valve  124  is provided by frusto-conical plunger  128  biased upwardly against mating valve seat  130  by compression spring  132  bearing at its lower end against stationary snap ring  134 . When the pressure in plenum  64  increases sufficiently to overcome the bias of spring  132 , plunger  128  moves downwardly away from valve seat  130  to permit flow therepast. 
     A precleaner  136 , FIGS. 4,  5 , at input  26  is provided by an inertial air-oil separator  138 , FIG. 3, having a plurality of nozzles  140  accelerating the air-oil stream, and an inertial collector  142  in the path of such stream and causing a sharp directional change thereof. Nozzles  140  are provided by a plurality of apertures in a disc  144  held in input  26  by stationary snap ring  146 , FIG.  5 . Collector  142  is provided by a rough, porous collection surface as in commonly owned copending U.S. application Ser. No. 09/356,072, filed Jul. 16, 1999. The collection surface is provided on an inner recessed surface  144  of the housing. The rough porous collection surface causes oil particle separation from the air-oil stream of smaller size oil particles than a smooth, non-porous impactor impingement surface and without size cut-off of the latter, to improve overall efficiency including for particles smaller than the cut-off size for a smooth, non-porous impactor impingement surface. Precleaner  136  is upstream of filter element  34  and provides extended life of filter element  34 . Bypass valve  124  communicates with plenum  64  downstream of precleaner  136 . 
     A vacuum control module  150 , FIG. 2, is provided in housing  24  between plenum  68  and outlet  30 , FIGS. 6,  9 . The module has a valve  152 , FIG. 9, having a normally open position such that intake manifold vacuum and/or turbo charger inlet vacuum is communicated back through outlet  30 , housing  24 , and inlet  26  to engine crankcase  28 , such that air and oil flow from crankcase  28  to housing inlet  26  into plenum  64  then through filter element  34 , and then air flows through second plenum  68  then through valve  152  as shown at arrow  154 , FIG. 9, then through housing outlet  30  to intake  32  of the engine. Valve  152  has a vacuum actuated closed position, which is the position illustrated in FIG. 9, blocking air flow therethrough. Valve  152  is actuated to the closed position in response to a predetermined vacuum in engine intake  32 , to prevent communication of excessive vacuum to crankcase  28  through housing  24 . Valve  152  is reciprocal between its open and closed positions along a lateral axis of movement  156  perpendicular to vertical extension  46  of housing  24  and perpendicular to longitudinal extension  52  of housing  24 . Valve  152  is provided by a flat disc diaphragm  158  extending vertically and longitudinally in the housing and moveable laterally along axis  156  against a valve seat  160  to the closed position. Diaphragm  158  has a first side  162  facing laterally toward and engageable with valve seat  160 , and has a second side  164  facing laterally oppositely from first side  162 . Second plenum  68  communicates with first side  162 . A compression spring  166  biases diaphragm  158  away from valve seat  160  such that air from plenum  68  flows past valve seat  160  to outlet  30 . The noted predetermined vacuum from engine intake  32  overcomes the bias of spring  166  to pull diaphragm  158  laterally along axis  156  against valve seat  160  to the closed position. 
     Module  150 , FIGS. 2,  9 , is provided by a pair of cup-like housing sections  168 , 170  pinching and sealing the outer periphery of diaphragm  158  therebetween. Housing section  170  is nested in raised annular shoulder  172  of clamshell half  106  and held securely therein in friction fit relation by O-ring  174 . Housing section  168  is nested in raised annular shoulder  176  of clamshell half  104  and held therein in friction fit and sealing relation by O-ring  178 . Outlet  130  includes an inner leg  180  extending into opening  182  of housing section  168  and through opening  184  of clamshell half  104  and sealed thereto by grommet  186 . Housing section  168  has a plurality of apertures  188  providing communication therethrough between plenum  68  and valve  152 . 
     As noted above, upper border end  92  of filter element  34  has closure plate  94  attached thereto. The closure plate mates with clamshell halves  104  and  106  and closes opening  90 , such that filter element  34  and closure plate  94  form a module which completes housing  24  formed by clamshell halves  104  and  106 . Filter element  34  is a flat low profile element. Housing  24  has the noted first flat low profile plenum  64  facing first side  36  of the filter element, and a second flat low profile plenum  68  facing the second side  38  of the filter element. Clamshell half  104  has first, second and third border fences  190 ,  192  and  194 , respectively, FIG. 2, mating with filter element  34  and having inner edges forming the noted filter mount guide channels  74 ,  76  and  72 , respectively. Closure plate  94  has a first section  196  adjacent first side  36  of filter element  34  and providing a fourth border fence. The first, second, third and fourth border fences  190 ,  192 ,  194  and  196  define a perimeter which in turn defines and extends around first plenum  64 . Second clamshell half  106  has fifth, sixth and seventh border fences  198 ,  200  and  202 , respectively, mating with filter element  34  and forming at their inner edges the noted filter mount guide channels  74 ,  76  and  72 , respectively. Top closure plate  94  has a second section  204  adjacent second side  38  of filter element  34  and providing an eighth border fence. The fifth, sixth, seventh and eighth border fences  198 ,  200 ,  202  and  204 , respectively, define a perimeter which in turn defines and extends around second plenum  68 . Border fence  202  has a cut-out  206  therein, FIGS. 2,  9 , permitting passage of air from second plenum  68  to valve  152  and outlet  30 . Border fence  200  has a cut-out  208 , FIGS. 2,  7 , permitting passage of oil from second plenum  68  to drain  58 . Housing  24  extends vertically from the noted fourth and eighth border fences  196  and  204  downwardly to the noted second and sixth border fences  192  and  200 . The housing extends longitudinally from the noted first and fifth border fences  190  and  198  to the noted third and seventh border fences  194  and  202 . First border fence  190 , FIG. 4, has a first opening  210  therein at inlet  26 , and a second opening  212  therein providing bypass port  122 . Housing  124  has a lower chamber  214 , FIGS. 2,  7 ,  8 , below the noted second and sixth border fences  192  and  200  and communicating with second plenum  68  through cut-out  208  in sixth border fence  200 . Lower chamber  214  provides a collection chamber for separated oil, and has the noted drain port  58  therefrom. 
     The noted combination of valves  124  and  152  maintains engine crankcase pressure within a desired range. Valve  124  prevents excessive positive pressure in the crankcase otherwise caused by plugging of filter element  34 . Valve  152  prevents excessive negative pressure in the crankcase otherwise caused by a high vacuum condition of the engine intake communicated back through housing  24 . The noted valving is provided in a compact low profile flat modular filter housing. Flat disc diaphragm  158  extends vertically and longitudinally in the housing, i.e. along the plane of the housing, and its opening and closing movement is along lateral axis  156  perpendicular to such vertical and longitudinal plane of the housing. This facilitates flat low profile construction. Axis  156  is parallel to the direction of flow through filter element  34  from first side  36  to second side  38 . The direction of oil and air flow from inlet  26  to first side  36  of the filter element is along the plane of the housing, and the direction of air flow from second side  38  of the filter element to valve  152  is also along the plane of the housing. Valve  124  is reciprocal between its open and closed positions along an axis of movement along the plane of the housing. First and second valves  124  and  152  are at distally opposite ends of the housing and separated by filter element  34  therebetween. The housing is mounted in the engine compartment in the preferred vertical orientation by mounting tabs  220 ,  222 ,  224 . 
     It is recognized that various equivalents, alternatives and modifications are possible within the scope of the appended claims.