Abstract:
An internal combustion engine includes a cooling fluid circuit and a pumping circuit. The pumping circuit drives an ejector pump located along the cooling fluid circuit, enabling a reduced parasitic load on the engine from pumping cooling fluid through the cooling fluid circuit.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority to U.S. Provisional Patent Application No. 61/447,538, filed on Feb. 28, 2011, which is hereby incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates to a system for pumping cooling fluid or coolant in an internal combustion engine using waste heat. 
       BACKGROUND 
       [0003]    Cooling an internal combustion engine represents a parasitic load on the engine because the cooling pump takes power provided by the internal combustion engine and uses that power to pump a cooling fluid or coolant through the internal combustion engine. If the size of the pump could be reduced by using a portion of the waste heat produced by an engine to assist in pumping the cooling fluid, the parasitic load would be reduced, increasing the efficiency of the internal combustion engine. 
       SUMMARY 
       [0004]    This disclosure provides an internal combustion engine comprising an engine body, and exhaust system connected to the engine body, a cooling fluid circuit, and a pumping system. The exhaust system is adapted to receive an exhaust gas from the engine body and includes a heat exchanger. The cooling fluid circuit is adapted to cool the engine body. The cooling fluid circuit contains a coolant and includes a radiator. The pumping system is connected to the cooling fluid circuit at a first location between the radiator and the engine body, upstream from the engine body, and at a second location between the engine body and the radiator, downstream of the engine body. The pumping system includes a fluid pump adapted to cause a portion of the coolant to flow through the heat exchanger. The pumping system also includes an ejector pump positioned at a second location to receive the coolant from the heat exchanger to cause a pumping action on the coolant in the cooling fluid circuit to cause the coolant in the cooling fluid circuit to circulate between the engine body and the radiator. 
         [0005]    This disclosure also provides an internal combustion engine comprising an engine body, an exhaust system connected to the engine body, a cooling fluid circuit, and a pumping system. The exhaust system is adapted to receive an exhaust gas from the engine body. The exhaust system includes a heat exchanger. The cooling fluid circuit is adapted to cool the engine body. The cooling fluid circuit contains a coolant and includes a radiator. The pumping system is connected to the cooling fluid circuit at a first location between the radiator and the engine body, upstream from the engine body, and at a second location between the engine body and the radiator, downstream of the engine body. The pumping system includes a fluid pump positioned upstream from the heat exchanger and operable to move coolant through the heat exchanger. The pumping system also includes an ejector pump positioned at the second location and adapted to receive the coolant from the pumping system to cause the coolant in the cooling fluid system to circulate in the cooling fluid system between engine body and the radiator. 
         [0006]    This disclosure also provides a method of pumping coolant in the internal combustion engine. The method comprises forming a cooling fluid circuit extending from a radiator to an engine body and containing a coolant. The method further comprises diverting a portion of the coolant from the cooling fluid circuit into a pumping circuit by the action of a fluid pump. The method also comprises transferring heat from an exhaust gas flowing from the engine body to the coolant flowing through the pumping system, causing the coolant to expand. The method also comprises positioning an ejector pump downstream from the heat exchanger and the engine body and connecting the expanding coolant and the cooling fluid circuit to the ejector pump so that the flow of expanding coolant through the ejector pump causes the coolant in the cooling fluid circuit to circulate through the cooling fluid circuit. 
         [0007]    Advantages and features of the embodiments of this disclosure will become more apparent from the following detailed description of exemplary embodiments when viewed in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a schematic of a first exemplary embodiment of the present disclosure. 
           [0009]      FIG. 2  is a schematic of a second exemplary embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Referring now to  FIG. 1 , an internal combustion engine  10  incorporating a first exemplary embodiment of the present disclosure may include an engine body or block  12 , a cooling fluid circuit  14  to direct cooling fluid or coolant through engine body  12 , a pumping system  16  to pump cooling fluid through engine body  12 , an exhaust system  18 , and a control system  20 . 
         [0011]    Cooling fluid circuit  14  may include a radiator  24 , which may be a heat exchanger or cooler. Pumping system  16  may include a conventional ejector pump  22  and a fluid pump  26 . Exhaust system  18  may include an exhaust manifold  28 , a heat exchanger/boiler  30 , and a downstream flow path  32 . Control system  20  may include a control module  34 , a wire harness  36 , a first temperature sensor  38  and a second temperature sensor  40 . 
         [0012]    Control module  34  may be an electronic control unit or electronic control module (ECM) that monitors the performance of engine  10  or may monitor other vehicle conditions. Control module  34  may be a single processor, a distributed processor, an electronic equivalent of a processor, or any combination of the aforementioned elements, as well as software, electronic storage, fixed lookup tables and the like. Control module  34  may connect to certain components of engine  10  by wire harness  36 , though such connection may be by other means, including a wireless system. Control module  34  may include a digital or analog circuit. 
         [0013]    Cooling fluid circuit  14  extends from radiator  24  to engine body  12 , and back to radiator  24 . Ejector pump  22  is positioned along cooling fluid circuit  14  downstream from engine body  12  and upstream from radiator  24 . Radiator  24  may be passively cooled by air, ram air, or other cooling methods  42 . 
         [0014]    Pumping system  16  fluidly connects to cooling fluid circuit  14  at a location downstream from radiator  24  and upstream of engine body  12 , and extends through heat exchanger  30  to connect with ejector pump  22  at a second location along cooling fluid circuit  14  downstream of engine body  12 . Fluid pump  26  is positioned along pumping system  16  upstream from heat exchanger  30 . 
         [0015]    Exhaust system  18  extends from exhaust manifold  28  to downstream flow path  32 . Heat exchanger  30  may be positioned between exhaust manifold  28  and downstream flow path  32 . Heat exchanger  30  may be positioned adjacent to exhaust manifold  28 , integrated into exhaust manifold  28 , or positioned a spaced distance downstream from exhaust manifold  28 . Downstream flow path  32  may include exhaust gas recirculation (not shown), aftertreatment components (not shown), turbocharger turbines (not shown), and other elements. 
         [0016]    Cooling fluid or coolant may be stored throughout cooling fluid circuit  14 , including radiator  24  and engine body  12 . When engine  10  first starts, fluid pump  26  begins to circulate coolant through pumping system  16 . Fluid pump  26  may have a relatively small pumping capacity. For example, fluid pump  26  may be capable of pumping or diverting only 3% to 10% of the total coolant flow into pumping system  16 , with the remainder flowing through cooling fluid circuit  14  once the system reaches full flow. 
         [0017]    As the pumped coolant flows from pumping system  16  into and through ejector pump  22 , the action of the fluid pumped into ejector pump  22  and thus fundamental effect of the ejector pump, causes coolant to be drawn into cooling fluid circuit  14  downstream of engine body  12  and through ejector pump  22  causing the combined flow to exit ejector pump  22 . As a result, coolant is pumped, or flows, through cooling fluid circuit  14 . Ejector pump  22  may also be described as a Venturi ejector pump or a Venturi pump. The coolant flowing through cooling fluid circuit  14  circulates from radiator  24  through engine body  12 , thereby cooling engine body  12 . The coolant then flows through ejector pump  22  by the action of fluid flowing from pumping system  16  through ejector pump  22 . The combined flow then returns to radiator  24 . 
         [0018]    As combustion occurs within engine body  12 , heated exhaust gas from a plurality of engine cylinders  13  formed within engine body  12  flows into exhaust system  18 . The temperature of the exhaust gas rises quickly. As the exhaust gas flows through heat exchanger  30 , the exhaust gas raises the temperature of the coolant flowing through pumping system  16 , causing the coolant flowing through pumping system  16  to expand. The expansion of the coolant increases the volume of flow through ejector pump  22  from pumping system  18 , which increases the amount of coolant in cooling fluid circuit  14  flowing through ejector pump  22 . Eventually, the temperature of the exhaust gas raises the temperature of the coolant to its phase change point, when at least some of the liquid changes from a liquid to a gas, forming a high-energy mixed phase fluid flow. The rapidly expanding coolant flows into ejector pump  22 , which increases the volume of coolant pumped by ejector pump  22  through cooling fluid circuit  14 , maintaining the temperature in engine body  12  within a desirable range. The coolant from pumping system  16  joins the coolant in cooling fluid circuit  14 , returning any gaseous coolant to a liquid state since the volume of the gaseous coolant is relatively small in comparison to the volume of coolant flowing through cooling fluid circuit  14  and because of the temperature of the coolant flowing through cooling fluid circuit  14 . 
         [0019]    Control system  20  may assist in determining the amount of coolant that fluid pump  26  directs into pumping system  16 . Control module  34  of control system  20  may receive a temperature signal from first temperature sensor  38  positioned along pumping system  16  downstream from heat exchanger  30 . Control module  34  may also receive a temperature signal from second temperature sensor  40  positioned along cooling fluid circuit  14  downstream from engine body  12 . Control system  20  may use the temperature signals to determine the amount of cooling required from cooling fluid circuit  14 . Of course, in other embodiments, these temperature signals may be used in combination with other signals (not shown) received from engine  10 . Control system  20  may then adjust the volume of fluid diverted into pumping system  16  by sending a control signal to fluid pump  26  to vary the speed of operation of pump  26  to thereby control the amount of coolant ejector pump  22  circulates within cooling fluid circuit  14 . For example, when additional fluid circulation is desired in cooling fluid circuit  14  and the temperature within heat exchanger  30  is sufficient to vaporize the coolant flowing through heat exchanger  30 , which may be indicated by temperature sensor  38 , ECU or control module  34  sends a signal to fluid pump  26  to increase the flow rate of coolant into pumping system  16 . The increased flow of coolant into pumping system  16  increases the amount of coolant vaporized within heat exchanger  30 , increasing the volume of flow into ejector pump  22  from pumping system  16 , which increases the flow rate of coolant in cooling fluid circuit  14 . Conversely, when less fluid circulation is desired in cooling fluid circuit  14 , which may be indicated by temperature sensor  40 , ECU  34  sends a signal to fluid pump  26  to decrease the flow rate of coolant into pumping system  16 , which decreases the flow of vaporized coolant through ejector pump  22 , decreasing the flow of coolant in cooling circuit  14 . Thus, fluid pump  26  is operable to pump to the minimum extent necessary to circulate fluid within cooling fluid circuit  14 , decreasing the load that cooling fluid circuit  14  would normally place on engine  10 , thus increasing the efficiency of engine  10 . Fluid pump  26  may be any type of pump capable of variable speed operation or variable displacement operation that enables adjusting the rate of flow through pumping system  16 . 
         [0020]    Referring now to  FIG. 2 , an internal combustion engine  110  incorporating a second exemplary embodiment of the present disclosure may include engine body or block  12 , cooling fluid circuit  14  to direct cooling fluid or coolant through engine body  12 , a pumping system  116  to pump cooling fluid through engine body  12 , exhaust system  18 , and a control system  120 . Elements having the same number as the previous embodiment function as described in the previous embodiment and described again in this embodiment only for clarity. 
         [0021]    Cooling fluid circuit  114  may include ejector pump  22 , radiator  24 , which may be a heat exchanger or cooler, and a check valve  48 . Pumping system  116  may include fluid pump  26  and a bypass valve  44 . Control system  120  may include a control module  134 , a wire harness  136 , first temperature sensor  38  and second temperature sensor  40 . 
         [0022]    Control module  134  may be an electronic control unit or electronic control module (ECM) that monitors the performance of engine  110  or may monitor other vehicle conditions. Control module  134  may be a single processor, a distributed processor, an electronic equivalent of a processor, or any combination of the aforementioned elements, as well as software, electronic storage, fixed lookup tables and the like. Control module  134  may connect to certain components of engine  110  by wire harness  136 , though such connection may be by other means, including a wireless system. Control module  134  may be a digital or analog circuit. 
         [0023]    Cooling fluid circuit  114  extends from radiator  24  to engine body  12 , and back to radiator  24 . Ejector pump  22  is positioned along cooling fluid circuit  114  downstream from engine body  12  and upstream from radiator  24 . Radiator  24  may be passively cooled by air, ram air, or other cooling methods  42 . Cooling fluid circuit  114  may also include check valve  48 . Check valve  48  may be positioned between engine body  12  and radiator  24 . 
         [0024]    Pumping system  116  fluidly connects to cooling fluid circuit  14  at a location downstream from radiator  24  and upstream of check valve  48 , and extends through heat exchanger  30  to connect with ejector pump  22  at a second location along cooling fluid circuit  14  downstream from engine body  12 . Fluid pump  26  may be positioned along pump system  116  upstream from heat exchanger  30 . Bypass valve  44  may be positioned along pump system  116  between fluid pump  26  and heat exchanger  30 . A bypass flow path  46  may extend from bypass valve  44  to engine body  12 . 
         [0025]    Exhaust system  18  may be configured as described in the previous embodiment. 
         [0026]    Coolant may be stored throughout cooling fluid circuit  114 , including radiator  24  and engine body  12 . When engine  110  first starts, control system  120  may operate fluid pump  26  at full speed and may operate bypass valve  44  to send fluid flow through bypass path  46  into engine body  12 . The purpose of this fluid flow is to provide cooling of engine  110  during cold start and light duty operation when the temperature of the exhaust flowing through heat exchanger is insufficient to expand or vaporize the coolant flowing through pumping system  116  a sufficient amount to cause adequate coolant flow through cooling fluid circuit  114 . 
         [0027]    Bypass valve  44  may operate as a proportional valve movable to partial open/closed positions or may be modulated or cycled rapidly between positions, also called binary operation or modulation. After the cooling fluid enters engine body  12  via bypass path  46 , the cooling fluid re-enters cooling fluid circuit  114 , which extends through engine body  12 . Check valve  48  or another device having a function similar to check valve  48  may prevent the flow of cooling fluid upstream from engine body  12  to radiator  24 . Fluid pump  26  may have a pumping capacity sufficient to pump or divert up to approximately 50% of the total engine coolant flow into pumping system  116 , with the remainder flowing through cooling fluid circuit  14  once the system reaches full flow. 
         [0028]    As engine  110  operates, the temperature of exhaust gas flowing through heat exchanger  30  increases through the action of the combustion process associated with cylinders  13 . The increasing temperature of the exhaust gas entering exhaust system  116  increases the ability of heat exchanger  30  to expand or vaporize the coolant flowing through pumping system  30 , which may be detected by temperature sensor  38  or other temperature sensors associated with the temperature of the exhaust gas from engine  110 . Once the temperature of heat exchanger  30  is sufficient to provide adequate flow through ejector pump  22  by way of the expanding coolant, which may be detected by temperature sensor  38 , temperature sensor  40 , or by other means, ECU  134  may send a control signal to bypass valve  44  to direct coolant through heat exchanger  30 . The temperature of heat exchanger  30  then increases the temperature of the coolant to its phase change point, when at least some of the coolant vaporizes, forming a high-energy mixed phase fluid flow. The expanding coolant flows through ejector pump  22 , which increases circulation of coolant through cooling fluid circuit  114  beyond the capability of pump  26  alone because of the heat energy transferred to the coolant in pumping system  116 . 
         [0029]    The rapidly expanding cooling fluid flows into ejector pump  22 , which increases the volume of cooling fluid pumped by ejector pump  22  through cooling fluid circuit  114  beyond the capability of pump  26  alone because of the heat energy transferred to the coolant in pumping system  116 , maintaining the temperature in engine body  12  within a desirable range for operation. The coolant from pumping system  16  joins the coolant in cooling fluid circuit  114 , returning any gaseous coolant to a liquid state because of the volume and temperature of the coolant flowing through cooling fluid circuit  114 . The combined flow returns to radiator  24 . 
         [0030]    Control system  120  may optimize the amount of cooling fluid that fluid pump  26  directs into pumping system  16  and into cooling circuit  114 . Control module  134  of control system  120  may receive a temperature signal from first temperature sensor  38  positioned along pumping system  116  downstream from heat exchanger  30 . Control module  134  may also receive a temperature signal from second temperature sensor  40  positioned along cooling fluid circuit  114  downstream from engine body  12 . Control system  120  may use the temperature signals to determine the amount of cooling required from cooling fluid circuit  114 . In other embodiments, these temperatures signals may be used in combination with other signals (not shown) received from engine  110 . Control system may then send control signals to adjust the position of bypass valve  44  and the speed of fluid pump  26 . Adjusting the position of bypass valve  44  and the speed of fluid pump  26  controls the volume of cooling fluid diverted into pumping system  116 , which controls the amount of cooling fluid ejector pump  22  circulates within cooling fluid circuit  114 , as described in the previous embodiment. Since ejector pump  22  provides the primary motive force for circulating cooling fluid within cooling fluid circuit  114 , control system  120  may operate fluid pump  26  to the minimum extent necessary to operate ejector pump  22  to circulate fluid within cooling fluid circuit  114 . Thus, the configuration of engine  110  is capable of decreasing the load that cooling fluid circuit  114  would normally place on engine  110 , thus increasing the efficiency of engine  110 . 
         [0031]    While various embodiments of the disclosure have been shown and described, it is understood that these embodiments are not limited thereto. The embodiments may be changed, modified and further applied by those skilled in the art. Therefore, these embodiments are not limited to the detail shown and described previously, but also include all such changes and modifications.