Patent Publication Number: US-11022011-B2

Title: Oil pan

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage of PCT Application No. PCT/FR2017/052816 filed on Oct. 12, 2017, which claims priority to French Patent Application No. 16/60104 filed on Oct. 18, 2016, the contents each of which are incorporated herein by reference thereto. 
     TECHNICAL FIELD 
     The present invention concerns an oil pan intended to be fixed under the engine block of an internal combustion engine. 
     BACKGROUND 
     The main function of an oil pan is to contain the oil needed to lubricate an engine and to dissipate some of the heat generated by the engine. 
     Conventionally, an oil pan includes a shell which is fixed under the engine block. 
     During operation, the oil present in the pan is sucked by an oil pump and is propelled to the various engine members to be lubricated (for example, camshafts, valve stems, crankshaft bearings, piston/cylinder, piston/connecting rod, crankshaft/connecting rod interfaces, etc.), then the oil returns to the pan by natural run-off or channelized return depending on the case. 
     The pan receives in its interior volume a strainer allowing to stop solid materials such as filings produced by the engine members contained in the oil before reaching the suction orifice of the pump, and a plate called anti-emulsion plate, whose role is to prevent or limit the movements of the oil in the pan, particularly at the free surface of the oil. 
     During its path, the oil is heated by the engine parts and cooled in the oil pan. 
     When starting the engine, the engine members are at ambient temperature. During the transitional phase of temperature rise to the optimum operating temperature, the engine does not operate optimally and particularly the fuel consumption proves to be substantially higher; this is because the combustion does not occur at optimum temperature. 
     In a general issue of optimizing the operation of an engine in order to reduce its consumption, a search pathway aims at reducing the duration of the transitional startup phase so that the engine reaches its optimum operating temperature as quickly as possible. 
     BRIEF SUMMARY 
     In this context, the purpose of the present invention is to provide an oil pan which allows decreasing the heating time of the oil of the engine lubrication circuit and therefore decreasing the fuel consumption when starting the engine as well as the carbon dioxide emissions. 
     According to a general definition, the invention concerns an oil pan comprising a lower shell intended to contain oil for lubricating an engine block, in which an oil flow, called sucked oil flow, is sucked by a suction tube for supplying a lubrication circuit and an oil flow, called returning oil flow, falls into the oil pan. The oil pan comprises an anti-emulsion plate disposed in the oil pan and orientation means allowing to orient at least a portion of the returning oil flow to an area located at the mouthpiece of the suction tube for a transitional period during which the oil has a temperature lower than an optimum operating temperature. 
     Thus, the invention provides an oil pan which allows the oil flow returning to the pan (that is to say an oil flow which, when in contact with the members that it has lubricated, is at a temperature which is higher than the temperature of the oil stored in the pan which is for its part at a temperature substantially equal to the ambient temperature) to make a short path by leading the returning oil flow directly to the mouthpiece of the suction tube of the oil pump. In other words, during the startup transition phase, the oil flow returning into the pan is directly sucked by the oil pump without having dissipated the heat that it carries in the oil mass of the pan. The invention establishes a bypass of the returning oil flow in order to retain the heat contained therein and to directly use the returning oil flow to supply the lubrication circuit. 
     Indeed, during the transitional period, the sucked oil flow mostly comes from the oil flow returning from the lubrication circuit. When in contact with the engine parts, the returning oil flow rises in temperature. Thus, the oil flow sucked during the transitional period, mostly contains oil heated by the engine members, which accelerates the rise in temperature of the sucked oil to its optimum operating temperature. In other words, the repeated re-use, during the transitional period, of the returning oil flow as a sucked oil flow allows accelerating the temperature rise of the sucked oil by avoiding a cooling caused by the mixing of the returning oil flow with the oil stored in the lower shell. The rapid rise in temperature of the sucked oil to its optimum temperature allows decreasing the heating time of the engine lubrication circuit. Thus, the invention provides an oil pan which allows decreasing the heating time of the oil of the engine lubrication circuit. The engine more quickly reaches its optimum operating temperature and therefore allows lowering the fuel over-consumption during the engine startup phase as well as reducing carbon dioxide emissions. 
     The orientation means may comprise a bypass tube opening at a first end into an opening of the anti-emulsion plate and at a second end into the mouthpiece of the suction tube. 
     The bypass tube and the suction tube can open into a casing having an opening allowing the oil stored in the lower shell to be sucked. 
     The bypass tube and the suction tube may comprise a platen connecting the bypass tube and the suction tube, the plate can be adapted to be fixed to the casing. 
     According to a first embodiment, the orientation means may comprise a bimetal shutter positioned in the opening of the anti-emulsion plate. The bimetal shutter can be movable between an open position in which the oil can flow into the opening and a closed position in which the bimetal shutter closes off the opening. The bimetal shutter can be adapted to switch to the closed position when the oil reaches or exceeds its optimum temperature. 
     The anti-emulsion plate may have a series of orifices for the passage of the oil flow returning to the lower shell. 
     According to one embodiment, the orientation means may comprise a series of bimetal shutters each positioned on a passage orifice. The bimetal shutters are movable between a closed position in which the bimetal shutters close off the passage orifices and an open position in which the oil can flow into the passage orifices. The bimetal shutters are adapted to switch to the open position when the oil reaches or exceeds its optimum temperature. 
     According to another embodiment, the orientation means may comprise a grid, the grid may have a plurality of micro-perforations, the micro-perforations being configured to be traversed by the oil reaching or exceeding a determined viscosity. The rise in the oil temperature allows changing the oil viscosity. 
     The anti-emulsion plate may comprise a gutter in which the opening and the passage orifices are positioned. 
     The gutter may have a slope adapted to promote the oil flow to the opening of the anti-emulsion plate. 
     The anti-emulsion plate may have a curved geometry adapted to recover the oil coming from the engine block. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the invention will emerge from the following description with reference to the appended drawings that show two embodiments of the invention. 
         FIG. 1  is a perspective view of a pan according to the invention; 
         FIG. 2  is a perspective view of a first embodiment of an anti-emulsion plate connected to a bypass tube, according to the invention; 
         FIG. 3  is a perspective view of a second embodiment of an anti-emulsion plate according to the invention; 
         FIG. 4  is a sectional perspective view of a first embodiment of a bypass tube and a suction tube according to the invention; 
         FIG. 5  is a sectional perspective view of a second embodiment of a bypass tube and a suction tube according to the invention; 
         FIGS. 6 and 7  are schematic representations of the operation of an oil pan according to the invention comprising an anti-emulsion plate according to a first embodiment; 
         FIGS. 8 and 9  are schematic representations of the operation of a third embodiment of an oil pan according to the invention. 
     
    
    
     With reference to  FIG. 1 , the invention concerns an oil pan  1  intended to be fixed to an engine block. 
     DETAILED DESCRIPTION 
     The oil pan  1  comprises in particular a lower shell  2 , a suction tube  44  connected at one of its ends to an oil pump and which opens at its second end into the lower shell  2 , an anti-emulsion plate  8  and orientation means which allow orienting a returning oil flow. A strainer is positioned at the mouthpiece of the suction tube  44  in order to stop solid materials such as filings produced by the engine members contained in the oil. 
     The lower shell  2  has a substantially parallelepiped shape with an upper opening  21 . The opening  21  is surrounded by a flange  22 . The flange  22  has bores  23  allowing to fix an anti-emulsion plate  8  to the lower shell  2 . The bottom shell  2  is adapted to contain oil. According to the example presented here, the lower shell  2  is made of polymeric material. According to other embodiments, the lower shell  2  could, for example, be made of aluminum casting. 
     The anti-emulsion plate  8  is intended to cover the upper opening  21  of the lower shell  2 . According to the example presented here, the anti-emulsion plate  8  is made of polymeric material. According to other embodiments, the anti-emulsion plate  8  could, for example, be made of aluminum. The anti-emulsion plate  8  has a collection segment  81 . The collection segment  81  has two fixing flanges  82 . Each fixing flange has bores  83  for fixing the anti-emulsion plate  8  to the lower shell  2 . The fixing of the anti-emulsion plate  8  to the lower shell  2  may for example be made with bolts or rivets. The collection segment  81  has a substantially semi-cylindrical section. The collection segment  81  comprises a bottom area offset in the direction of the bottom of the lower shell  2  relative to the fixing flanges  82 . The bottom area comprises a gutter  84 . The gutter  84  has a bottom wall  84   a  and flanks  84   b.    
     According to a first embodiment, the oil passage orifices  86  are formed in the flanks  84   b  of the gutter  84 . 
     An opening  87  is formed in the bottom wall  84   a . The bottom wall  84   a  is inclined on both sides of the opening  87 , so that the opening  87  is at the low point of the bottom wall  84   a.    
     According to the first embodiment, shown in  FIG. 2 , the opening  87  is closed off by a bimetal shutter  88  to switch it from its passing position to its non-passing position. The bimetal shutter  88  is movable between an open position in which the opening  87  allows passage of the oil and a closed position in which the bimetal shutter  88  closes off the opening  87 . The bimetal shutter  88  is configured to switch to the closed position when the oil circulating on the anti-emulsion plate  8  reaches or exceeds an optimum temperature of the engine operation which is usually comprised between 30° C. and 50° C. 
     According to a second embodiment, shown in  FIG. 3 , the gutter  84  comprises a grid  89 . The grid  89  has a plurality of micro-perforations which are the passage orifices  86 . The opening  87  passes through the grid  89 , such that the opening  87  is not concealed by the grid  89 . The micro-perforations of the grid  89  are configured to be traversed by the oil when the oil reaches or exceeds a defined viscosity associated with a defined temperature. 
     According to a third embodiment, shown in  FIGS. 8 and 9 , the passage orifices  86  are closed off by bimetal shutters  90 . The bimetal shutters  90  are movable between a closed position in which the bimetal shutters  90  close off the passage orifices  86  and an open position in which the oil can flow into the passage orifices. The bimetal shutters  90  are adapted to switch to the open position when the oil reaches or exceeds its optimum temperature. 
     The orientation means comprise a bypass tube  41 . The bypass tube  41  opens at a first end into the opening  87  of the anti-emulsion plate  8  and at a second end into the mouthpiece of the suction tube  44 . The bypass tube  41  and the suction tube  44  open into a casing  45 . The casing  45  has an opening  42  allowing the oil stored in the lower shell  2  to be sucked. 
     The bypass tube  41  and the suction tube  44  comprise a platen  43  which connects the bypass tube  41  and the suction tube  44 . The platen is adapted to be fixed to the casing  45 . 
     In conditions of use, when the engine is stopped, the majority of the oil is in the lower shell  2  of the oil pan  1 . From the startup of the engine, a sucked oil flow I is sucked through the suction tube  44  by the oil pump. The oil circulates in the engine parts to ensure their lubrication. When returning, the returning oil flow II falls on the anti-emulsion plate  8 . 
     According to the first embodiment, whose operation is shown in  FIGS. 6 and 7 , when starting the engine, the bimetal shutter  88  is in the open position because the oil has not yet reached its optimum temperature. The returning oil flow II mostly flows through the opening  87 . The inclination of the bottom wall  84   a  of the gutter  84  promotes  1   o  the oil flow to the opening  87 . It is however possible that a minor amount of oil also flows through the orifices  86  and falls into the lower shell  2 . The returning oil flow II which flows through the opening  87  passes through the bypass tube  41  and flows to the mouthpiece of the suction tube  44  where it is sucked and becomes the sucked oil flow I. 
     Thus, the sucked oil flow I which passes through the suction tube  44  mainly contains oil directly coming from the engine that has already been heated when in contact with the engine elements. When the returning oil flow II present on the anti-emulsion plate reaches or exceeds its optimum temperature, the bimetal shutter  88  switches to the closed position. In this case, all the returning oil flow flows through the orifices  86  in the lower shell  2 , as shown in  FIG. 7 . The sucked oil flow I then comes from the lower shell  2  and passes through the opening  42  of the casing  45  in order to pass through the suction tube  44 . 
     Thus, the first embodiment comprises active orientation means whose change of state allows the orientation of the returning oil flow II. 
     According to the second embodiment, the returning oil flow flows on the grid  89 . As long as the returning oil flow has not reached or exceeded a defined temperature, the returning oil flow cannot pass through the grid  89 . In this case, all the returning oil flow flows through the opening  87  in the bypass tube  41 . When the returning oil flow reaches or exceeds a defined viscosity, the returning oil flow can pass through the grid  89  and flow through the passage orifices  86 . The change in viscosity of the oil flow is caused by the change in temperature of the oil flow. The returning oil flow then flows through the passage orifices  86  and through the opening  87 . The sucked oil flow I then partly comes from the lower shell  2  and passes through the opening  42  of the casing  45  in order to pass through the suction tube  44 . Thus, the second embodiment comprises passive orientation means. The change of temperature and fluidity of the oil allows, or does not allow, the returning oil flow to pass through the grid  89 . 
     It is also possible to combine the first and the second embodiment by jointly using the grid  89  and the bimetal shutter  88 . 
     According to the third embodiment, the returning oil flow II flows on the anti-emulsion plate  8 . As long as the oil has not reached its optimum temperature, the bimetal shutters  90  are in the closed position and close off the passage orifices  86 . During this period, the oil therefore flows through the opening  87  in the bypass tube  41 . When the returning oil flow II reaches or exceeds its optimum operating temperature, the bimetal shutters  90  switch to the open position and the oil flows through the passage orifices  86 . 
     Thus, the third embodiment comprises active orientation means whose change of state allows the orientation of the returning oil flow II. 
     It is possible to combine the first and third embodiment. 
     Of course, the invention is in no way limited to the embodiments described above and illustrated by the various figures, these embodiments having been given only as examples. Modifications remain possible, in particular from the point of view of the substitution of technical equivalents without departing from the scope of the invention. Thus, it is possible to replace the bimetal shutters by other thermostat trigger devices of the wax capsule or shape memory alloy type.