Abstract:
A separator for a closed crank case ventilation system has an upstream located inlet and downstream gas and oil outlets. A plurality of flat plate baffles alternately extend from opposing side walls to form a tortuous path for blow by gasses to separate the oil from the gasses. The separator is located upstream from the crankcase depression regulator such that the pressure differential between the separator and the crankcase is minimal to allow the oil to easily open the check valve and return to the crankcase.

Description:
TECHNICAL FIELD 
     The field of this invention relates separators in a closed crankcase ventilation system. 
     BACKGROUND OF THE DISCLOSURE 
     Government regulations relating to environmental concerns have mandated that many engines have a closed crankcase ventilation system. Commonly, these closed systems re-circulate any blow-by gases escaping from the combustion chambers and passing into the crankcase back into the air intake system. These blow-by gases, which are loaded with unburned gaseous hydrocarbons, are then re-circulated back to the intake manifold to be burned upon the next pass into the engine. 
     However, the crankcase gases are also usually loaded with oil particulates. Under extreme conditions, excess oil passing through the intake system may cause harm to the engine and cause more pollutants than what was being eliminated by the re-circulation of the blow-by gases. Thus, oil needs to be separated out before the gases are reintroduced into the air intake system of the engine and re-burned. 
     One present in-line closed re-circulation system is disclosed in U.S. Pat. No. 4,724,807 which has an in-line separator made with conduits with arcuate channel walls forming a convoluted arcuate pathway for the exhaust gas/oil mixture. The separator is interposed between the clean air intake filter and the turbo-compressor air inlet system. The position of this separator requires that the separator have a moderately small size to fit between the air filter and turbo intake and requires that it be downstream from the crankcase depression regulator. These factors limit the capacity and effectiveness of the separator returning oil against a substantial differential pressure to the positively pressured crankcase. 
     What is needed is an expeditiously constructed separator system that has enough capacity to prevent oil from entering the air intake in a cylinder kit failure situation and eliminates the resistance of draining oil back into a positively pressurized crankcase. 
     In addition, there is a need for a separator system that protects the engine against a sudden increase in oil discharge due to operating conditions, including extreme tilt of the engine during operation. 
     SUMMARY OF THE DISCLOSURE 
     In accordance with one aspect of the invention, a closed crankcase re-circulation system for an internal combustion engine includes an exhaust gas-oil separator operably interposed between an engine breather and a crankcase depression regulator. The exhaust gas-oil separator has an inlet in communication with an outlet of an engine breather for communication with the internal space of the crankcase. Commonly, the engine breather may be mounted in the rocker arm cover with the engine block and cylinder heads having passages to the crankcase. 
     A gas outlet is in communication with a line leading to an air intake system of the engine. The gas outlet is positioned at a high portion of the separator. The line has a crankcase depression regulator mounted downstream from the separator. An oil drain outlet is in communication with the crankcase for draining oil back thereto. 
     Preferably the separator is longitudinally extending from the inlet to the outlet and drain. The oil drain outlet is at a lower portion of the separator. Baffles are interposed between the inlet and the gas and oil drain outlets. Preferably the baffles transversely and alternately extend from opposite sides of the separator to form a convoluted passage for the blow by gasses as they pass from the inlet to the gas outlet. 
     The separator desirably has a floor surface canted downwardly from the inlet to the oil drain outlet with the oil drain outlet located at a low portion of the canted floor surface to provide for flow of the separated oil to the oil drain outlet. 
     In one embodiment the separator has a generally frusto-conical shape extending from the inlet to the gas outlet and oil drain outlet. In this embodiment, it is preferable that each baffle has an oil drain passage located at a low lateral point at the floor surface to provide for downward flow of the oil through the baffle and toward the drain. It is also preferable that a filter media is interposed between an end wall in proximity to the gas outlet and a last downstream baffle. The filter media is operable interposed between the gas outlet and the oil drain outlet. 
     In another embodiment, the separator has a generally rectangular shape in plan view with vertical sidewalls and vertical end walls. The floor surface is generally flat in the lateral direction. The baffles alternately extend from the vertical sidewalls. It is desirable in this embodiment that the inlet is positioned at an upper section of one end wall adjacent a higher end of the floor surface. The gas outlet is positioned at an upper section of an opposite end wall adjacent to the lower end of the floor surface. The oil drain outlet is positioned at a lower section of the opposite end wall. 
     In accordance with another aspect of the invention, a separator for a closed crankcase ventilating system includes a generally longitudinally and horizontally extending body with an inlet at an upstream end and a gas outlet and oil drain outlet at a downstream end. The separator has a floor surface canted downwardly from the upstream end to the downstream end. The oil drain outlet is located at a low portion of the canted floor surface. A plurality of baffles transversely extend laterally within the body and are alternately to opposite sides of the body. 
     Preferably, the separator body has a generally frusto-conical shape extending from the inlet to the gas outlet and oil drain outlet. Preferably, each baffle has an oil passage located at a low lateral point at the floor surface to provide for downward flow of the oil through the baffle and toward the oil drain outlet. 
     In this fashion, a separator has the efficiency and capacity to adequately separate sufficient oil form the crankcase gases in a situation where a cylinder kit fails which significant blow by of oil and blow by gasses pass into the crankcase. In this way, the air intake system and turbo charge system are more adequately protected when a cylinder kit failure occurs. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Reference now is made to the accompanying drawings in which: 
     FIG. 1 is a side elevational view of an engine incorporating a separator in accordance with one embodiment of the invention; 
     FIG. 2 is an enlarged side elevational view of the separator shown in FIG. 1; 
     FIG. 3 is a plan view of the separator with the top removed for viewing the baffles therein; 
     FIG. 4 is an end view of the downstream end of the separator; 
     FIG. 5 is a view similar to FIG. 1 illustrating a second embodiment of the invention; 
     FIG. 6 is an enlarged side elevational and partially segmented view of the separator shown in FIG. 5; 
     FIG. 7 is an end view from the downstream end of the separator shown in FIG. 6; and 
     FIG. 8 is a top plan view showing the alternating baffles within the separator. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, an engine  10  has an oil breather  12  connected to the rocker arm cover  13 . The breather  12  is connected to a line  16  that is connected to an inlet  18  of a separator  20  often referred to as an air-oil separator. The separator  20  has a drain outlet  22  connected to a line  24 , preferably with a one way check valve  26  therein that leads back to the crankcase  28  in engine  10 . The oil breather  12  is conventionally in communication with the crankcase  28  via passages through the engine block and cylinder head that are not shown for simplicity of the drawing. 
     The separator  20  also has an outlet  30  that is connected to a line  32  that has a crankcase depression regulator  34 . The line  32  extends beyond the crankcase depression regulator  34  and is connected to the air intake system generally indicated at  35 . The air intake system  35  has an air intake  36  and turbocharger  38  which has a line  40  leading back into the intake manifold  42 . The turbocharger  38  is driven by exhaust gases passing from exhaust manifold  39  to exhaust line  41 . 
     The separator  20  can be described in more detail with reference to FIGS. 2-4. As shown in these figures, the general shape of the separator  20  is rectangular in the plan view as shown in FIG.  3 . The separator has a flat top  42  with vertical opposing side walls  44 , vertical opposing inlet end wall  46  and downstream end wall  48  and a sloping or canting floor surface  50  as shown in FIG.  2 . This shape is more conducive to packaging or placing the air oil separator  20  above the engine where a wide flat shape is desirable for packaging purposes. 
     The floor surface  50  slopes downwardly from the inlet end wall  46  to the outlet end wall  48 . The inlet  18  intrudes at an upper section of the inlet end wall  48 . The inlet  18  may be an extending inlet pipe  52  for allowing a line to be easily coupled thereto. The downstream end wall has an oil drain outlet  22  at a lower section at the floor surface and a gas outlet  30  at an upper end of the end wall  48 . As shown in FIG. 4, the two outlets  30  and  22  are placed at opposing corners of the downstream end walls and may be similarly constructed to inlet  18  with an extending pipe  52 . 
     As shown in FIG. 3, a plurality of flat plate baffles  58  extend from the two side walls  44  in alternating fashion to provide a zig-zag convoluted path for the gas and oil flow within the separator to provide sufficient length and turbulence to drop the oil particulates from the blow-by gasses during the gasses tortuous path through the oil gas separator. The dropped oil flows on the floor surface  50  following the convoluted path along the downward slope to the drain outlet  22 . The oil then passes through the connected line  24  and through the one way check valve  26  and back to the crankcase  28 . The pressure differential between the separator and the crankcase is insignificant because crankcase depression regulator  80  is downstream from the separator. Thus, the mere weight of the oil is sufficient to open the check valve  26  and allow the oil to reenter the crankcase. The gases also continue along the tortuous path provided by the baffles to the upper gas outlet  30 . The gasses pass the crankcase depression regulator  80  and back into the air intake system. 
     The separator  20  is sized sufficiently to provide for substantial separation of oil from blow by gasses in the event that a cylinder kit completely fails. While this size varies with relation to the size of the engine and size of the cylinders, an air oil separator having the interior dimensions of 12 inches in length, 8 inches in width and 6 to 8 inches in depth is sufficient size for an engine such as a commercially available Detroit Diesel Series 2000® marine pleasure craft engine. The baffles will cause an average minimum path length of approximately 24 inches for this dimensioned separator between the inlet and gas outlet. Additional plate baffles will increase the path length from this disclosed preferred embodiment. 
     A second embodiment is disclosed in FIGS. 5-8. In this embodiment the separator  120  is placed along the side of the engine  10 . The outer shape of the separator  120  has a substantially frusto-conical tubular wall  154  with a longitudinal axis. The tubular wall  154  is capped at each end with vertical upstream end wall  146  and downstream end wall  148 . The longitudinal axis of the separator  120  is generally horizontal such that it has a downwardly sloping or canting floor surface  150  as shown in FIG.  2 . This shape is a more conducive package when the separator  120  is positioned at a side of the engine  10 . Usually a relatively narrow and longer shape is desirable for packaging purposes at a side of an engine. 
     The floor surface  150 , which is merely a lower section of the frusto conical body wall  154 , slopes downwardly from the inlet end wall  146  to the outlet end wall  148 . An inlet  118  intrudes at an upper section of the inlet end wall  148 . The downstream end wall  148  has a gas outlet  130  at an upper end of the end wall  148 . An oil drain outlet  122  extends from the lower end of the floor surface  150  adjacent the end wall  148 . As shown in FIG. 7, the two outlets  130  and  122  are both near the center vertical longitudinal plane of the air oil separator. 
     As shown in FIG. 8, a plurality of straight plate baffles  158  extend from the opposing side sections  144  of the frusto conical body wall in alternating fashion to provide a zig-zag convoluted path for the gas flow within the separator to provide sufficient length and turbulence to drop the oil particulates from the entering crankcase blow-by gasses during its tortuous path through the oil gas separator. This dropped oil then flows from the point that it drops onto the floor surface  150  to a lower midpoint in proximity to the vertical center plane. Each baffle  158  has a flow through passage  160  along the vertical midplane to allow the oil to flow down the floor surface  150  to the oil drain outlet  154 . The oil then passes through the connected line  24  and through the one way check valve  26  and back to the crankcase oil supply in the same fashion as with the first previously described embodiment. 
     As shown in FIG. 6, an optional filter  162  may be interposed between the last downstream baffle  158  and the downstream end wall  148  such that all blow by gasses must pass up through the filter  162  to reach the outlet  152 . The filter provides further chances for remaining oil particles to condense or hit the filter and drop back onto the floor surface  150  and pass to the oil drain outlet  154 . 
     The length and inner upstream and downstream diameters for the frusto conical body again can vary with the particular application. It is foreseen that for the above mention commercially available engine, a length of 12 inches and upstream and downstream inside diameters of 6 and 8 inches, respectively is suitable dimensions for a Detroit Diesel 2000 marine pleasure craft engine. 
     In this fashion, substantially all significant amounts of oil are separated from the blow by gasses that enter the separator before the blow by gasses are returned to the intake manifold. The oil is easily returned to the crankcase thereby preventing any back up of blocked conditions. Furthermore, the separator is easily constructed with flat plate baffles housed in an easily constructed housing. 
     Variations and modifications are possible without departing from the scope and spirit of the present invention as defined by the appended claims or plan.