Patent Publication Number: US-2016237867-A1

Title: Oil pan and engine assembly including the oil pan

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/115,358, filed Feb. 12, 2015, which is hereby incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to an oil pan and an engine assembly including the oil pan. 
     BACKGROUND 
     An oil pan can collect oil used to lubricate an internal combustion engine. During operation of the internal combustion engine, oil may circulate within the internal combustion engine to lubricate moving components of the internal combustion engine, dissipate thermal energy, and protect against wear of the internal combustion engine. After lubricating the moving parts of the engine, the oil is collected by the oil pan. 
     SUMMARY 
     To maximize fuel efficiency when an internal combustion engine is warming up, the oil in the oil pan should be heated to an optimum temperature as quickly as possible. When the oil is at its optimum temperature, fuel dilution in the oil can be minimized. In addition, the moisture in the oil can be minimized by maintaining the oil temperature at its optimum level, thereby maximizing the engine oil life. Accordingly, the presently disclosed engine assembly includes an oil pan capable of minimizing the time it takes to heat the oil when the internal combustion engine is warming up. In an embodiment, an engine assembly includes an oil pan having an oil pan body. The oil pan body includes an inner pan surface defining a cavity configured to collect oil and an outer pan surface opposite the inner pan surface. The engine assembly further includes a heat exchanger disposed within the cavity. The heat exchanger is submerged in the oil collected in the cavity of the oil pan and can receive a heat transfer fluid in order to facilitate heat transfer between the oil in the cavity and the heat transfer fluid flowing through the heat exchanger. It is contemplated that the heat exchanger may be positioned under the pump intake of an oil pump inside the cavity of the oil pan, thereby facilitating cooling or heating of the oil independently of the oil pump flowrate. Alternately, the pump pickup tube inlet may be located below the heat exchanger to maximize oil flow through the heat exchanger. Because the heat exchanger is disposed inside the cavity, the oil pan body can be wholly or partly made of a light weight material, such as a polymer, a composite material, or any suitable polymeric material. The present disclosure also relates to a vehicle including the engine assembly described above. 
     The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the teachings when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of a vehicle including an engine assembly in accordance with an embodiment of the present disclosure, wherein the engine assembly includes an oil pan; 
         FIG. 2  is a schematic, perspective view of the oil pan shown in  FIG. 1 , wherein the oil pan includes a heat exchanger; 
         FIG. 3  is a schematic, top view of the oil pan of  FIG. 2 ; 
         FIG. 4  is a schematic, perspective view of the oil pan without the heat exchanger; and 
         FIG. 5  is a schematic, cross-sectional view of the oil pan shown in  FIG. 2 , taken along section line  5 - 5  of  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, wherein like reference numbers correspond to like or similar components throughout the several figures, referring to  FIGS. 1-5 , a vehicle  10 , such as a car, includes an engine assembly  12 . The engine assembly  12  includes an internal combustion engine  14  configured to propel the vehicle  10 . The internal combustion engine  14  employs oil O for lubrication, among other things. The engine assembly  12  further includes an oil pan  16  coupled to the internal combustion engine  14 . As a consequence, oil O can flow between the internal combustion engine  14  and the oil pan  16 . Specifically, the oil O used to lubricate the internal combustion engine  14  can flow to the oil pan  16 . The oil pan  16  then collects the oil O. The engine assembly  12  further includes an oil pump  18  coupled to the oil pan  16 . Consequently, the oil pump  18  can move the oil O from the oil pan  16  back to the internal combustion engine  14  as well as to other vehicle components. The oil pump  18  includes a pump intake  19 , such as a channel, a pipe, or a conduit, configured to receive the oil O in the cavity  44 . The pump intake  19  is in fluid communication with the cavity  44  (specifically the first compartment  54 ) in order to allow oil O to flow from the cavity  44  (specifically the first compartment  54 ) into the oil pump  18 . The oil pump  18  is at least partially disposed inside the cavity  44 . 
     To maximize fuel efficiency when the internal combustion engine  14  is warming up, the oil O in the oil pan  16  should be heated to an optimum temperature as quickly as possible. When the oil O is at its optimum temperature, fuel dilution in the oil can be minimized. Additionally, the moisture in the oil O can be minimized by maintaining the oil temperature at its optimum level, thereby maximizing the engine oil life. The oil pan  16  of the engine assembly  12  can minimize the time it takes to heat the oil O when the internal combustion engine  14  is warming up as discussed below. 
     The oil pan  16  is configured to hold the oil O and includes an oil pan body  36  having a plurality of walls  38 . For example, in the depicted embodiment, the oil pan body  36  includes at least one sidewall  38   a  defining the perimeter of the oil pan  16  and at least one bottom wall  38   b  coupled to the sidewalls  38   a.  The sidewalls  38  include a top wall portion  38   c.  The oil pan body  36  defines an inner pan surface  40  and an outer pan surface  42  opposite the inner pan surface  40 . The inner pan surface  40  defines the open cavity  44  configured, shaped, and sized to collect and hold the oil O. The oil pan body  36  may be wholly or partly made of a polymeric material, such as a polymeric composite material, in order to minimize costs. Alternatively, the oil pan body  36  may be wholly or partly made of a metallic material, such as a casted metal (e.g., cast iron) in order to enhance the structural integrity of the oil pan  16 . 
     The oil pan  16  includes a dividing wall  53  coupled to at least one of the walls  38 . For example, the dividing wall  53  can be coupled to the sidewall  38   a  and/or the bottom wall  38   b.  Regardless, the dividing wall  53  divides the cavity  44  into the first compartment  54  and a second compartment  56 . The second compartment  56  is larger than the first compartment  54 . In other words, the first compartment  54  has a volume (i.e., the first volume) that is less than the volume (i.e., the second volume) of the second compartment  56  in order to minimize the time it takes to warm up the oil O in the oil pan  16 , because the oil O is first heated or cooled in the first compartment  54  as discussed in detail below. As a non-limiting example, the volume of the first compartment  54  may range between ¼ to ⅕ of the total volume of the cavity  44 , whereas the volume of the second compartment  56  may range between ¾ and ⅘ of the total volume of the cavity  44 . These volume ranges ensure that the oil O in the first compartment  54  is heated (or cooled) as quickly as possible, because the first compartment  54 , which is the smaller compartment, is used to warm up the oil O. Warming up the oil O first in the first compartment  54  helps reduce friction in the internal combustion engine  14 . Accordingly, the oil O should initially be directed to the first compartment  54 . 
     The oil pan  16  further includes a drip pan  60  to direct the oil O stemming from other vehicle components, such as the internal combustion engine  14 , into the first compartment  54 . The drip pan  60  is coupled to the sidewall  38   a  and is at least partly disposed within the cavity  44 . Moreover, the drip pan  60  is obliquely angled relative to the sidewall  38   a  and may extend along the entire length of the second compartment  56  in order to direct the oil O toward the first compartment  54 . At least a portion of the drip pan  60  is disposed over the dividing wall  53 . However, the drip pan  60  is spaced apart from the dividing wall  53  so as to define a gap G therebetween. Instead of (or in addition to) the drip pan  60 , the oil pan  16  may include diverters to direct the oil O toward the first compartment  54 . The gap G allows oil O to flow over the dividing wall  53  when the amount of oil O in either the first compartment  54  or the second compartment  56  reaches a certain level. The height of the sidewall  38   a  (i.e., the first height H 1 ) is greater than the height of the dividing wall  53  (i.e., the second height H 2 ) in order to allow the oil pan  16  to hold the oil O even while the oil O is flowing over the dividing wall  53  through the gap G. 
     The oil pan  16  has a compartment opening  58 , such as a thru-hole, extending through the dividing wall  53 , and the engine assembly  12  includes a valve  62  coupled to the dividing wall  53  in order to open or close the compartment opening  58 . Thus, the valve  62  is at least partly disposed within the compartment opening  58  and may be a flapper valve or any kind of valve suitable to block fluid flow (e.g., oil flow) between the first compartment  54  and the second compartment  56  via the compartment opening  58 . Accordingly, the valve  62  can move between an open position and a closed position. When the valve  62  is in the open position, the first compartment  54  is in fluid communication with the second compartment  56  through compartment opening  58  and, therefore, the oil O can flow between the first compartment  54  and the second compartment  56  via the compartment opening  58 . In the closed position, the valve  62  blocks fluid flow between the first compartment  54  and the second compartment  56 . 
     The engine assembly  12  includes a heat exchanger  32  disposed within the first compartment  54 . The heat exchanger  32  is placed directly under the pump intake  19  of the oil pump  18  in order to reduce heat losses to the atmosphere. Alternately, the pick-up tube may extend through the heat exchanger so that the pick-up tube inlet is below the heat exchanger to ensure all oil drawn into the pick-up tube has passed through the heat exchanger. This may be facilitated by a pick-up tube integrated with the heat exchanger and sealed to the pump when the oil pan is assembled to the engine. When the first compartment  54  is filled with oil O, the heat exchanger  32  may be submerged in the oil O. Because the heat exchanger  32  is disposed inside the cavity  44 , the oil pan body  36  can be wholly or partly made of a light weight material, such as a polymer, a composite material, or any suitable polymeric material. Using a light weight material for the oil pan  16  enhances the fuel economy of the vehicle  10 . The heat exchanger  32  is disposed closer to the bottom wall  38   b  of the oil pan body  36  than to the top wall portion  38   c  in order to facilitate heat transfer between the oil O in the cavity  44  and heat transfer fluid F flowing through the heat exchanger  32 . Further, the heat exchanger  32  may include a plurality of tubes  64  extending through the first compartment  54 . Each tube  64  is configured to carry the heat transfer fluid F. Accordingly, the heat transfer fluid F can flow through the tubes  64  of the heat exchanger  32  in order to facilitate heat transfer between the oil O in the first compartment  54  and the heat transfer fluid F flowing through the heat exchanger  32 . The heat exchanger  32  further includes a bar  76  interconnecting the tubes  64 . Fasteners  72  extend through the bar  76  and into the oil pan body  36  inside the cavity  44  in order to couple the heat exchanger  32  (and the tubes  64 ) to the oil pan body  36 . 
     The heat exchanger  32  can be at least partially disposed between the oil pump  18  and the bottom wall  38   b  in order to facilitate heat transfer between the heat transfer fluid F and the oil O. Specifically, the heat exchanger  32  can be placed directly under the pump intake  19  in order to facilitate heat transfer between the heat transfer fluid F flowing through the heat exchanger  32  and the oil O in the cavity  44  independently of the oil pump flowrate. 
     The oil pan  16  defines a wall opening  66  ( FIG. 4 ) extending through the oil pan body  36 . In the depicted embodiment, the wall opening  66  extends through one of the walls  38 . For example, the wall opening  66  can extend through one of the sidewalls  38   a  of the oil pan body  36 . The wall opening  66  leads to the cavity  44  (e.g., the first compartment  54 ) and is configured, shaped, and sized to partially receive the heat exchanger  32 . Accordingly, the heat exchanger  32  is partially disposed through the wall opening  66  and outside the cavity  44  of the oil pan body  36 . In other words, a portion of the heat exchanger  32  extends through the wall opening  66 . The oil pan  16  also includes a liquid-impermeable seal  68  coupled to the oil pan body  36  and disposed around the wall opening  66  in order to inhibit the mixture of the heat transfer fluid F flowing through the heat exchanger  32  and the oil O disposed in the cavity  44  of the oil pan  16 . Specifically, the liquid-impermeable seal  68  at least partially surrounds the heat exchanger  32  (especially the portion of the heat exchanger  32  extending through the wall opening  66 ) in order to prevent the heat transfer fluid F from leaking into the cavity  44 . The portion of the heat exchanger  32  disposed outside the cavity  44  is referred to as the outer exchanger portion  70  ( FIG. 2 ). The liquid-impermeable seal  68  can be made of any suitable liquid-impermeable material, such as rubber. The outer exchanger portion  70  extends beyond the boundaries of the wall opening  66  in order to prevent leaks of heat transfer fluid F into the cavity  44  of the oil pan  16 . A plurality of fasteners  72 , such as screws or bolts, can extend through the outer exchanger portion  70  and the oil pan body  36  in order to couple the heat exchanger  32  to the oil pan body  36 . The oil pan body  36  includes a plurality of holes  74  ( FIG. 4 ) configured, shaped, and sized to receive the fasteners  72 . The holes  74  are arranged around the wall opening  66 , and each extends through the outer pan surface  42  and the inner pan surface  40 . 
     Fasteners  72  can also extend through an inlet  46  and the outer exchanger portion  70  in order to couple the inlet  46  to the outer exchanger portion  70 . Moreover, fasteners  72  can extend through an outlet  48  and the outer exchanger portion  70  in order to couple the outlet  48  to the outer exchanger portion  70 . The inlet  46  is in fluid communication with the tubes  64 . The outlet  48  is also in fluid communication with the tubes  64 . At least a portion of the inlet  46  extends through the top wall portion  38   c  of the oil pan body  36  in order to fix the inlet  46  relative to the oil pan body  36 . At least a portion of the outlet  48  extends through the top wall portion  38   c  of the oil pan body  36  in order to fix the outlet  48  relative to the oil pan body  36 . 
     The engine assembly  12  further includes a heat transfer fluid source  22  capable of holding the heat transfer fluid F. The heat transfer fluid F can be any fluid (e.g., liquid) suitable for transferring heat. As a non-limiting example, the heat transfer fluid F may be a coolant, such as ethylene glycol. The fluid source  22  is in fluid communication with an input passageway  24  (e.g., conduit, tube, pipe, etc.). The input passageway  24  is outside the oil pan  16  and is fluidly coupled between the oil pan  16  and the fluid source  22 . Accordingly, the heat transfer fluid F can flow from the fluid source  22  to the oil pan  16 . A fluid transfer pump  26  is also coupled to the input passageway  24  in order to move the heat transfer fluid F from the fluid source  22  to the oil pan  16  through the input passageway  24 . 
     The input passageway  24  is in thermal communication with a heat source  28 . As a consequence, the heat source  28  can heat the heat transfer fluid F flowing through the input passageway  24 . As non-limiting examples, the heat source  28  can be an exhaust manifold, an exhaust gas recirculation system, a turbocharger, an engine block, an engine head, or a combination thereof. Regardless of the kind of heat source  28  used, heat H can be transferred between the heat transfer fluid F flowing through the input passageway  24  and the heat source  28 . 
     The input passageway  24  is in thermal communication with a cooling source  30 . As a consequence, the cooling source  30  can cool the heat transfer fluid F flowing through the input passageway  24 . As a non-limiting example, the cooling source  30  can be the cooling system of the vehicle  10 . Irrespective of the kind of cooling source  30  used, heat H can be transferred between the heat transfer fluid F flowing through the input passageway  24  and the cooling source  30 . 
     The inlet  46  of the heat exchanger  32  may be a pipe, tube or any suitable conduit, and is in fluid communication with the fluid source  22  through the input passageway  24 . Therefore, the heat transfer fluid F can flow between the fluid source  22  and the heat exchanger  32 . Further, the outlet  48  of the heat exchanger  32  may be a pipe, tube or any suitable conduit, and is in fluid communication with the output passageway  34 . Thus, the heat transfer fluid F can flow from the heat exchanger  32  to an output passageway  34  after the heat has been transferred between the oil O in the first compartment  54  of the oil pan  16  and the heat transfer fluid F flowing through the heat exchanger  32 . Because the oil O in the oil pan  16  can be cooled by exchanging heat from the heat transfer fluid F, the engine assembly  12  does not need an oil cooler. Thus, the engine assembly  12  (and therefore the vehicle  10 ) does not have an oil cooler for cooling the oil O in the oil pan  16 . However, the second compartment  56  may also include a heat exchanger for cooling or heating the oil O. 
     The heat exchanger  32  is in fluid communication with the input passageway  24 . Accordingly, the heat transfer fluid F can flow between the input passageway  24  and the heat exchanger  32 . While flowing through the heat exchanger  32 , heat can be transferred between the oil O in the first compartment  54  and the heat transfer fluid F flowing through the heat exchanger  32 . The engine assembly  12  also includes the output passageway  34  (e.g., conduit, tube, pipe, etc.) outside the oil pan  16 . The output passageway  34  is in fluid communication with the heat exchanger  32 . Accordingly, the heat transfer fluid F can flow between the heat exchanger  32  and the output passageway  34  once heat has been transferred between the heat transfer fluid F flowing through the heat exchanger  32  and the oil O disposed in the oil pan  16 . It is contemplated that the oil pan  16  may include one or more heat exchangers  32 . Regardless of the quantity, the flowrate of the heat transfer fluid F flowing through the heat exchanger  32  can be adjusted by varying the power output of the fluid transfer pump  26  (i.e., the pump power). 
     The engine assembly  12  further includes a controller  50  in communication (e.g., electronic communication) with the fluid transfer pump  26 . Accordingly, the controller  50  may alternatively be referred to as a thermal control module and can command the fluid transfer pump  26  to adjust its power output (i.e., pump power). The controller  50  may include hardware elements such as a processor (P), memory (M), circuitry including but not limited to a timer, oscillator, analog-to-digital (A/D) circuitry, digital-to-analog (D/A) circuitry, a digital signal processor, and any necessary input/output (I/O) devices and other signal conditioning and/or buffer circuitry. The memory (M) may include tangible, non-transitory memory such as read only memory (ROM), e.g., magnetic, solid-state/flash, and/or optical memory, as well as sufficient amounts of random access memory (RAM), electrically-erasable programmable read-only memory (EEPROM), and the like. The controller  50  can send a signal (i.e., the power command signal P C ) to the fluid transfer pump  26  in order to increase or decrease its pump power. In other words, the controller  50  is programmed to adjust the pump power of the fluid transfer pump  26  in order to adjust the flowrate of the heat transfer fluid F flowing through the heat exchanger  32 . 
     The engine assembly  12  further includes a temperature sensor  52  in communication (e.g., electronic communication) with the controller  50 . The temperature sensor  52  may be a thermocouple or any other sensor suitable for measuring the temperature of the oil O. In the depicted embodiment, the temperature sensor  52  is disposed inside the first compartment  54  and can therefore measure the temperature of the oil O in the first compartment  54 . The controller  50  is programmed to receive a signal (i.e., the temperature signal T) from the temperature sensor  52 , which is indicative of the temperature of the oil O in the first compartment  54 . 
     The controller  50  is also in communication (e.g., electronic communication) with the valve  62 . Accordingly, the controller  50  can command the valve  62  to move between the open and closed positions. Specifically, the controller  50  is programmed to send a signal (i.e., valve signal V) to the valve  62 , thereby causing the valve  62  to move either to the open position or the closed position. For example, the controller  50  can be programmed to command the valve  62  to move from the closed position to the open position when the temperature of the oil O in the first compartment  54  is greater than a predetermined temperature (i.e., the first predetermined temperature). Further, the controller  50  can be programmed to command the fluid transfer pump  26  to adjust (e.g., increase) its pump power in order to adjust (e.g., increase) the flowrate of the heat transfer fluid F when the temperature of the oil O in the first compartment  54  is greater than another predetermined temperature (i.e., the second predetermined temperature). The second predetermined temperature may be greater than the first predetermined temperature. 
     Before starting the internal combustion engine  14 , the oil level may be above the height of the dividing wall  53  (i.e., the second height H 2 ). Thus, when the internal combustion engine  14  is off, the oil O can flow between the first compartment  54  and the second compartment  56  over the dividing wall  53 . However, at this juncture, the valve  62  is in the closed position. Accordingly, the oil O cannot flow between the first compartment  54  and the second compartment  56  through the compartment opening  58 . After the internal combustion engine  14  is started, the oil pump  18  moves some of the oil O out of the oil pan  16  and, therefore, the oil level decreases. At this point, the oil level does not reach the height of the dividing wall  53  (i.e., the second height H 2 ). Because at this point the valve  62  is still in the closed position, the oil O does not flow between the first compartment  54  and the second compartment  56  (either over the dividing wall  53  or through the compartment opening  58 ). 
     As the internal combustion engine  14  keeps running, the heat transfer fluid F is heated or cooled before being introduced into the heat exchanger  32 . To heat the heat transfer fluid F, heat can be transferred from the heat source  28  (e.g., exhaust manifold) to the heat transfer fluid F while the heat transfer fluid F is flowing through the input passageway  24  as discussed above. To cool the heat transfer fluid F, heat can be transferred from the heat transfer fluid F to the cooling source  30  while the heat transfer fluid F flows through the input passageway  24 . The heated or cooled heat transfer fluid F is then introduced into the heat exchanger  32  while the oil O is in the first compartment  54  of the oil pan  16 . At this juncture, the heat transfer fluid F flows through the heat exchanger  32  from the inlet  46  to the outlet  48 . While the heat transfer fluid F flows through the heat exchanger  32 , heat is transferred between the oil O disposed in the first compartment  54  of the oil pan  16  and the heat transfer fluid F flowing through the heat exchanger  32  in order to cool or warm up the oil O. Due to the heat transfer facilitated by the heat exchanger  32 , the temperature of the oil O in the first compartment  54  eventually reaches its optimum temperature (i.e., the first predetermined temperature). Once the temperature sensor  52  detects that the oil O in the first compartment  14  has reached the optimum temperature (i.e., the first predetermined temperature), the controller  50  receives a signal (i.e., the temperature signal T) from the temperature sensor  52 . Upon receipt of this temperature signal T, the controller  50  commands the valve  62  to move from the closed position to the open position. In response, the valve  62  moves from the closed position to the open position, thereby allowing the oil O to flow between the first compartment  54  and the second compartment  56  through the compartment opening  58 . If the temperature of the oil O exceeds an optimum temperature range, the flowrate of the heat transfer fluid F may be increased to cool the oil O in the oil pan  16 . For example, if the temperature of the oil O exceeds a maximum threshold temperature (i.e., the second predetermined temperature) as measured by the temperature sensor  52 , then the controller  50  can command the fluid transfer pump  26  to increase its pump power in order to increase the flowrate of the heat transfer fluid F flowing through the heat exchanger  32 . The increased flowrate of the heat transfer fluid F can help cool off the oil O in the oil pan  16  until the temperature of the oil O is less than the maximum threshold temperature (i.e., the second predetermined temperature). 
     While the best modes for carrying out the teachings have been described in detail, those familiar with the art to which this disclosure relates will recognize various alternative designs and embodiments for practicing the teachings within the scope of the appended claims.