Abstract:
The present invention provides an exhaust cooler mounted to a tailpipe for receiving exhaust gas. The exhaust cooler includes a jet pump connectable to the tailpipe and a nozzle connectable to the tailpipe. The nozzle defines a nozzle opening between the tailpipe and the jet pump for communicating the exhaust gas from the tailpipe to the jet pump. A first throttle member is included that is moveable between a closed position and an open position, the open position defining a first opening between the tailpipe and the jet pump for communicating the exhaust gas from the tailpipe to the jet pump.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present patent application is a continuation of U.S. application Ser. No. 11/677,133 filed on Feb. 21, 2007. 
     
    
     FIELD 
       [0002]    The present disclosure relates to exhaust coolers, and more particularly to a variable geometry exhaust cooler. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
         [0004]    Diesel engine systems are popular due to their generally high efficiency relative to other kinds of internal combustion engines. This efficiency is due, in part, to the increased compression ratio of the Diesel combustion process and the higher energy density of Diesel fuel. However, the Diesel combustion process does produce particulates that are carried in the exhaust gas produced by the Diesel engine system. 
         [0005]    A Diesel particulate filter is often used to remove these particulates from the exhaust gases. Typically, the Diesel particulate filter is coupled to the exhaust system downstream of the Diesel engine. The Diesel particulate filter receives the exhaust gas and filters particulates out of the exhaust gas. While useful for its intended purpose, the Diesel particulate filter can become full over time, and if not cleaned, the operating effectiveness of the Diesel particulate filter can be degraded. 
         [0006]    Another solution known in the art is to use a regeneration process to remove particulates trapped in the Diesel particulate filter. These regeneration processes may take various forms, such as, for example, exhaust gas recirculation or using post-combustion fuel injected into the cylinder in order to raise the temperature of the exhaust gas stream. An exemplary regeneration process is found in commonly owned U.S. Pat. No. 7,104,048 B2, hereby incorporated by reference as if fully disclosed herein. These regeneration processes typically heat the exhaust gasses to a high temperature in order to burn the particulates from the Diesel particulate filter. 
         [0007]    During conditions when the Diesel engine system is in an idle state, it is desirable to cool the exhaust gasses before they are expelled into the environment. Accordingly, an exhaust gas cooler may be coupled to the Diesel engine system downstream of the Diesel particulate filter to cool the exhaust gas. The exhaust gas cooler is operable to mix the hot exhaust gas with the cooler ambient air, thereby reducing the temperature of the exhaust gas. To do so, however, the amount of exhaust gas entering the exhaust cooler is typically restricted such that sufficient cooling can take place. This restriction of the exhaust gas can lead to back pressure, lowered horsepower, and other inefficiencies in the Diesel engine system when the Diesel engine system is running at a non-idle state and producing large amounts of exhaust gas. Accordingly, there is room in the art for an exhaust cooler that is operable to vary the amount of exhaust gas entering the exhaust cooler based on the operating state of the Diesel engine system. 
       SUMMARY 
       [0008]    The present invention provides an exhaust cooler mounted to a tailpipe for receiving exhaust gas. 
         [0009]    In one aspect of the present invention the exhaust cooler includes a jet pump connectable to the tailpipe and a nozzle connectable to the tailpipe. The nozzle defines an opening between the tailpipe and the jet pump for communicating the exhaust gas from the tailpipe to the jet pump. A first throttle member is included that is moveable between a closed position and an open position, the open position defining a first opening between the tailpipe and the jet pump for communicating the exhaust gas from the tailpipe to the jet pump. 
         [0010]    In another aspect of the present invention the first throttle member is a plate pivotally connectable to the tailpipe. 
         [0011]    In yet another aspect of the present invention a hinge is connectable between the tailpipe and the first throttle member to allow the first throttle member to pivot between the open and the closed positions. 
         [0012]    In still another aspect of the present invention a second throttle member is included that is moveable between a closed position and an open position, the open position defining a second opening between the tailpipe and the jet pump for communicating the exhaust gas from the tailpipe to the jet pump. 
         [0013]    In still another aspect of the present invention the first throttle member and the second throttle member are each semi-circular in shape and are sized to fit overtop the nozzle opening. 
         [0014]    In still another aspect of the present invention the first opening and the second opening are each semi-circular in shape. 
         [0015]    In still another aspect of the present invention when the first throttle member and the second throttle member are in the closed position, the first opening and the second opening cooperate to form a circular shaped opening. 
         [0016]    In still another aspect of the present invention the circular shaped opening has a diameter less than a diameter of the nozzle opening. 
         [0017]    In still another aspect of the present invention a biasing member is connectable to the tailpipe to bias the first throttle member to the closed position. 
         [0018]    In still another aspect of the present invention the biasing member is a torsional spring. 
         [0019]    In still another aspect of the present invention the first throttle member is a valve. 
         [0020]    In still another aspect of the present invention the valve is a reed type valve. 
         [0021]    In still another aspect of the present invention the nozzle has a frusto-conical shape and the valve is positioned on an outer surface of the frusto-conical nozzle. 
         [0022]    In still another aspect of the present invention a plurality of reed valves are spaced equidistance along the outer surface of the frusto-conical nozzle. 
         [0023]    In still another aspect of the present invention the jet pump is connectable to the tailpipe by a plurality of struts. 
         [0024]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0025]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0026]      FIG. 1  is a schematic view of an exemplary Diesel engine system having a variable exhaust cooler according to the principles of the present invention; 
           [0027]      FIG. 2A  is an enlarged schematic side view of the variable exhaust cooler of the present invention having throttle plates in a closed position when the exemplary Diesel engine system is in an idle state; 
           [0028]      FIG. 2B  is an enlarged schematic side view of the variable exhaust cooler of the present invention having throttle plates in an open position when the exemplary Diesel engine system is in a non-idle state; 
           [0029]      FIG. 3A  is an enlarged schematic side view of a second embodiment of the variable exhaust cooler of the present invention having valves in a closed position when the exemplary Diesel engine system is in an idle state; and 
           [0030]      FIG. 3B  is an enlarged schematic side view of the second embodiment of the variable exhaust cooler of the present invention having valves in an open position when the exemplary Diesel engine system is in a non-idle state. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
         [0032]    With reference to  FIG. 1 , an exemplary Diesel engine system is illustrated and generally indicated by reference number  10 . The Diesel engine system  10  is preferably employed in a motor vehicle (not shown), though the Diesel engine system  10  may be used in various other applications without departing from the scope of the present invention. The Diesel engine system  10  generally includes a Diesel engine  12 . The Diesel engine  12  is in electronic communication with an engine controller  14 . The engine controller  14  is operable to control the Diesel engine  12  based on various parameters. 
         [0033]    The Diesel engine  12  is operable to combust Diesel fuel (not shown) in a combustion process within the Diesel engine  12 . The by-product of this combustion process is an exhaust gas. The exhaust gas is discharged from the Diesel engine  12  as an exhaust gas stream into an exhaust pipe  16 , as indicated by the arrows in  FIG. 1 . 
         [0034]    The exhaust pipe  16  includes a first section  18  that communicates the exhaust gas from the Diesel engine  12  to a catalyst  20  located downstream of the Diesel engine  12 . The catalyst  20  is mounted to the exhaust pipe  16 . The catalyst  20  may be any exhaust scrubbing device, such as, for example, an NOx filter. The catalyst  20  is operable to filter the exhaust gas to meet applicable emissions standards. 
         [0035]    A second section  22  of the exhaust pipe  16  carries the exhaust gas from the catalyst  20  to a Diesel particulate filter  24 . The Diesel particulate filter  24  is mounted to the exhaust pipe  16  and is located downstream of the catalyst  20  and the Diesel engine  12 . The Diesel particulate filter  24  filters the exhaust gas stream and traps particulates therein. The Diesel particulate filter  24  may take various forms without departing from the scope of the present invention. For example, the Diesel particulate filter  24  may include a ceramic structure through which the exhaust gas stream passes. The particulates are trapped and accumulate on the walls of the ceramic structure until such time as they are burned off in a regeneration process using hot exhaust gasses. 
         [0036]    The exhaust gas stream passes from the Diesel particulate filter  24  to a tailpipe section  26  of the exhaust pipe  16 . An exhaust cooler  30  is mounted to an end of the tailpipe section  26 . As will be described in greater detail below, the exhaust cooler  30  acts to cool the exhaust gas stream before the exhaust gas stream enters the surrounding environment. 
         [0037]    Turning now to  FIG. 2A , the exhaust gas cooler  30  generally includes a variable geometry nozzle assembly  32  coupled with a jet pump  34 . The nozzle assembly  32  is disposed on an end of the tailpipe section  26  and defines an opening  36 . Preferably, the opening  36  has a diameter equal to the diameter of the tailpipe section  26 . However, it should be appreciated that the opening  36  may have a diameter different than the diameter of the tailpipe section  26  without departing from the scope of the present invention. 
         [0038]    The nozzle assembly  32  further includes a first throttle plate  38 A and a second throttle plate  38 B. The throttle plates  38 A and  38 B are each generally semi-circular in shape and each have an outer diameter larger than the diameter of the opening  36 . Alternatively, the throttle plates  38 A and  38 B could have an outer diameter less than the opening  36  such that the throttle plates  38 A and  38 B fit within the opening  36 . The throttle plates  38 A and  38 B each respectively include a semi-circular opening or cut out  42 A and  42 B. The semi-circular cut outs  42 A and  42 B are concentric with the generally semi-circular shape of the throttle plates  38 A and  38 B, and each semi-circular cut out  42 A and  42 B has a diameter less than the outer diameter of the throttle plates  38 A and  38 B. 
         [0039]    The throttle plates  38 A and  38 B are each pivotally mounted to the tailpipe section  26  at the opening  36 . In the example provided, a first hinge  44 A pivotally couples the first throttle plate  38 A to the tailpipe section  26 . The first hinge  44 A is mounted to the tailpipe section  26  and is mounted to the circumferential center, or apex, of the semi-circular outer edge of the first throttle plate  38 A. A second hinge  44 B pivotally couples the second throttle plate  38 B to the tailpipe section  26 . The second hinge  44 B is mounted to the tailpipe section  26  at a position opposite the first hinge  44 A. The second hinge  44 B is also mounted to the circumferential center, or apex, of the semi-circular outer edge of the second throttle plate  38 B. While hinges  44 A and  44 B have been illustrated as pivotally coupling the throttle plates  38 A and  38 B to the tailpipe section  26 , it should be appreciated that various other mechanisms that allow the throttle plates  38 A and  38 B to pivot relative to the tailpipe section  26  may be employed without departing from the scope of the present invention. 
         [0040]    The throttle plates  38 A and  38 B are respectively biased to a closed position by a first biasing member  48 A and a second biasing member  48 B. In the preferred embodiment, the biasing members  48 A and  48 B are torsional springs, though various other biasing devices may be employed without departing from the scope of the present invention. 
         [0041]    The closed position of the throttle plates  38 A and  38 B is illustrated in  FIG. 2A . When in the closed position, the throttle plates  38 A and  38 B are positioned to at least partially cover the opening  36 . Furthermore, the cut outs  42 A and  42 B cooperate to define a reduced opening  50 . The reduced opening  50  has a diameter less than the diameter of the opening  36 . 
         [0042]    The jet pump  34  includes a cylindrical pipe portion  56 . An intake portion  58  is mounted on one end of the cylindrical pipe portion  56 . The intake portion  58  is generally frusto-conical in shape and defines an intake opening  60 . An output portion  62  is mounted on an opposite end of the cylindrical pipe portion  56 . The output portion  62  is also generally frusto-conical in shape and defines an exhaust output  64  at an end thereof. In an alternate embodiment, the jet pump  34  includes only the cylindrical pipe portion  56 . 
         [0043]    The jet pump  34  is mounted to the tailpipe section  26  by struts  66 . The struts  66  extend from the intake portion to the tailpipe section  26 . The jet pump  34  extends out from the tailpipe section  26  away from the nozzle assembly  32 . 
         [0044]    With reference to  FIG. 1  and continued reference to  FIG. 2A , in order to clean the Diesel particulate filter  24 , hot exhaust gas is passed through the exhaust pipe  16 , through the Diesel particulate filter  24 , and on to the exhaust cooler  30 . When the Diesel engine  12  is in an idle state, the hot exhaust gas passes through the nozzle opening  50 . Cooler ambient air is sucked through the intake opening  60  of the jet pump  34 . The hot exhaust gas and the cooler ambient air circulate and mix within the cylindrical pipe portion  56  and the output portion  62 . The hot exhaust gas is cooled and exits the exhaust cooler  30  from the exhaust output  64 . Hot exhaust ranging in temperature from 450-600 degrees Celsius at the nozzle opening  50  may be cooled to less than 300 degrees Celsius at the exhaust output  64 . 
         [0045]    As the exhaust gas stream leaves the Diesel engine  12 , the exhaust gas stream flows through the exhaust pipe  16 . As the exhaust gas stream  12  reaches the exhaust cooler  30 , the exhaust gas stream exerts a pressure on the throttle plates  38 A and  38 B. During idle conditions, the exhaust gas stream pressure is less than the force exerted on the throttle plates  38 A and  38 B by the biasing members  46 A and  46 B. Accordingly, the throttle plates  38 A and  38 B remain in the closed position and the nozzle opening  50  speeds up the exhaust gas as it passes through the restricted nozzle opening  50 , thereby entraining more air in the jet pump  34  and achieving increased cooling from the increased volume of entrained ambient air. 
         [0046]    When the Diesel engine  12  is running at non-idle conditions, the amount of exhaust gas produced by the Diesel engine  12  increases, and accordingly the pressure of the exhaust gas stream on the throttle plates  38 A and  38 B increases. This exhaust gas pressure is operable to move the throttle plates  38 A and  38 B into an open position. The open position of the throttle plates  38 A and  38 B is illustrated in  FIG. 2B . When the exhaust stream pressure exceeds the force exerted by the biasing members  46 A and  46 B on the throttle plates  38 A and  38 B, the throttle plates  38 A and  38 B are pivoted against the biasing members  46 A and  46 B on the hinges  44 A and  44 B. As the throttle plates  38 A and  38 B are pivoted away from each other, the opening from the tailpipe section  26  into the jet pump  34  increases in size from the area provided by the nozzle  50  to the area provided by the opening  36 . Accordingly, a larger amount of exhaust gas is allowed to pass from the nozzle assembly  30  into the jet pump  34 , thereby reducing back pressure and other inefficiencies at non-idle speeds. 
         [0047]    With reference to  FIG. 3A , a second embodiment of the exhaust gas cooler is generally indicated by reference number  130 . The exhaust gas cooler  130  generally includes the jet pump  34 , as described in  FIGS. 2A and 2B , and a nozzle assembly  132 . 
         [0048]    The nozzle assembly  132  is disposed on an end of the tailpipe section  26  and includes a nozzle  134 . The nozzle  134  has a generally frusto-conical shape and is hollow such that an interior of the nozzle  134  communicates with the tailpipe section  26  to receive the exhaust gas stream. The nozzle  134  further defines an outlet  136  at an end thereof. The outlet  136  has a diameter less than the diameter of the tailpipe section  26  and therefore restricts the amount of exhaust gas passing from the tailpipe section  26  to the jet pump  34 . 
         [0049]    A plurality of valves  140 , only two of which are shown, are located around an outer surface  142  of the nozzle  134 . The valves  140  are in communication with the interior of the nozzle  134  and in turn the exhaust gas stream within the tailpipe section  26 . In the preferred embodiment, six to eight valves are spaced evenly around the outer surface  142  of the nozzle  134 . However, it should be appreciated that any number of valves  140  may be employed with the present invention. The valves  140  are moveable between a closed position, as shown in  FIG. 3A , and an open position, as shown in  FIG. 3B . The valves  140  are biased toward the closed position. In the preferred embodiment, the valves  140  are reed type valves. However, it should be appreciated that various other types of valves may be employed with the present invention. 
         [0050]    During idle conditions, the exhaust gas stream pressure is not sufficient to open the valves  140 , and the valves remain in the closed position as illustrated in  FIG. 3A . Accordingly, the outlet  136  speeds up the exhaust gas stream as it passes through the restricted opening of the outlet  136 , thereby entraining more air in the jet pump  34  and achieving increased cooling from the increased volume of entrained ambient air. When the Diesel engine  12  is running at non-idle conditions, the amount of exhaust gas produced by the Diesel engine  12  increases, and accordingly the pressure of the exhaust gas stream on the valve  140  increases. This exhaust gas pressure is operable to move the valves  140  into the open position, as illustrated in  FIG. 3B . Accordingly, a larger amount of exhaust gas is allowed to pass from the nozzle assembly  130  into the jet pump  34 , thereby reducing back pressure and other inefficiencies at non-idle speeds. This allows the exhaust gas cooler  130  to automatically adjust to the operating state of the engine  12 . 
         [0051]    The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.