Patent Document

BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates generally to engine test cells used to test the performance of engines. More specifically, the present invention relates to an engine test cell method for changing different types of engines in and out of the test cell. 
         [0002]    A conventional engine test cell includes a dynamometer, an engine mount assembly, multiple engine stand jacks, an engine placed onto the engine mount assembly, and various heat exchangers, and various hose and pipe connections to provide the engine with the air and fluid necessary to run the engine. Other components can be used depending on the type of testing to be conducted. 
         [0003]    During the set-up of the test cell, the engine crankshaft is coupled to the dynamometer, which is used to measure the torque and rotational speed of the engine. The center of the crankshaft must be aligned to the center of the dynamometer shaft. This alignment process requires the test cell mechanics to adjust, shift and align various components using various tools until the center of the crankshaft is aligned with the center of the dynamometer shaft. Further, pipes need to be fabricated to run to and from the engine. 
         [0004]    In the conventional engine test cell, there is little to no standardization between the configurations of the test cell from engine to engine, and particularly, between engine families. For example, if one particular engine is set up in the test cell, and a second engine is to replace the first engine, various steps have to be taken to reconfigure the test cell during the changeover of the engines. Each engine changeover requires the mechanics to reset the jacks, realign the engine to the dynamometer, search for and fabricate air pipes and coolant hoses, among various other steps. 
         [0005]    All of the adjustments, measurements and alignments take an excessively long amount of time. In cases where engines of like families are changed over, the process takes approximately 4-hours. In cases where a different engine family is installed in a test cell, the process can take upwards of 16-hours. In addition to the amount of labor used for an engine changeover, there is also a resulting test cell downtime since the test cell cannot be used for testing during the changeover period. 
         [0006]    Thus, there is a need for a test cell changeover method that standardizes the engine changeover procedure. 
         [0007]    There is also a need for a test cell changeover method that significantly reduces the amount of time needed to change over an engine. 
         [0008]    Further, there is a need for a test cell changeover method that requires a minimal amount of tools. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    The above-listed needs are met or exceeded by the present method of changing-over engines in an engine test cell having a dynamometer and a dynamometer shaft defining a centerline, where the engine crankshaft defines a crankshaft centerline. The method includes the steps of providing a plurality of engine stands in predetermined locations in the test cell with respect to the dynamometer, attaching a set of mount assemblies to the engine in predetermined locations on the engine with respect to the crankshaft, where the set of mount assemblies is specific to the engine, and attaching the set of mount assemblies to the plurality of engine stands. Upon attachment of the set of mount assemblies to the engine and to the engine stands, the crankshaft centerline and the dynamometer centerline are automatically aligned without adjustment of the engine stands or of the set of mount assemblies. 
         [0010]    An alternate method of changing-over engines in an engine test cell having a dynamometer and a dynamometer shaft defining a centerline, where the engine crankshaft defines a crankshaft centerline is provided. The method includes the steps of selecting an engine to be tested in the test cell from a group of engines, selecting a set of engine mounts that are custom-made for the engine selected, and providing a plurality of engine stands in predetermined locations in the test cell with respect to the dynamometer. Also included are the steps of attaching the set of mount assemblies to the engine in predetermined locations on the engine with respect to the crankshaft, and attaching the set of mount assemblies to the plurality of engine stands. The predetermined locations of the plurality of engine stands in the test cell are the same irrespective of which engine is selected. 
         [0011]    A method of aligning a crankshaft centerline of an engine to a dynamometer shaft centerline in a test cell, wherein the test cell is defined by a horizontal direction “z”, is provided. The method includes the steps of providing a plurality of engine stands in predetermined locations in the test cell, where two of the engine stands are a distance z apart, and where the two engine stands are equidistant from the dynamometer shaft centerline a distance z/2. Also included are the steps of providing two mount assembly portions specific for the engine that attach to the engine at two, predetermined locations on the engine, where the predetermined engine locations are equidistant a distance z″ from the crankshaft centerline, and attaching the mount assembly portions to the engine and to the two engine stands, wherein the mount assembly portions generally extend a distance (z/2-z″) from the predetermined engine location. 
         [0012]    A method of attaching an engine mount assembly to an engine stand in an engine test cell is provided. The method includes providing a receiving portion on the engine stand, where the receiving portion is a channel having a pin extending from a bottom surface of the channel and extending generally parallel to the engine stand, where the pin has at least one detent. Also included are the steps of providing an extension portion on the engine mount assembly, where the extension portion extends generally perpendicularly to the pin and includes an aperture for receiving the pin, introducing the pin into the aperture to engage the extension portion into the channel, and providing a tool having at least one prong and engaging the prong into the detent to lock the extension portion to the receiving portion. 
     
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0013]      FIG. 1A  is a schematic representation of a test cell including a first engine, a dynamometer, and a plurality of engine stands, showing the positional relationship between the centerline C of the dynamometer shaft and the engine stands; 
           [0014]      FIG. 1B  is a schematic representation of the test cell of  FIG. 1A  including a second engine, the dynamometer, and the plurality of engine stands, showing the same positional relationship between the centerline C of the dynamometer shaft and the engine stands as  FIG. 1A ; 
           [0015]      FIG. 1C  is a front perspective view of the engine stand with a jack bracket tray; 
           [0016]      FIG. 1D  is a partial perspective view of a receiving portion of the engine stand; 
           [0017]      FIG. 2A  is a schematic representation of the test cell including the first engine and a first set of engine mounts, showing the positional relationship between a centerline C′ of the engine crankshaft and the first set of engine mounts; 
           [0018]      FIG. 2B  is a schematic representation of the test cell including the second engine and a second set of engine mounts, showing the positional relationship between the centerline C′ of the engine crankshaft and the second set of engine mounts; 
           [0019]      FIG. 3A  is a schematic representation of the test cell including the first engine, the engine stands, and the first set of engine mounts, showing the alignment of the centerline C′ of the engine crankshaft with the centerline C of the dynamometer shaft; 
           [0020]      FIG. 3B  is a schematic representation of the test cell including the second engine, the engine stands, and the second set of engine mounts, showing the alignment of the centerline C′ of the engine crankshaft with the centerline C of the dynamometer shaft; 
           [0021]      FIG. 4  is a front perspective view of a rear mount assembly including left and right rear mounts, a rear housing and left and right jack bracket trays; 
           [0022]      FIG. 5  is a front perspective view of a front mount assembly including a front mount bracket and left and right jack bracket trays; 
           [0023]      FIG. 6  is a front perspective view of a second rear mount assembly including left and right rear mounts and left and right jack bracket trays; 
           [0024]      FIG. 7  is a front perspective view of a second front mount assembly including a front mount bracket and left and right jack bracket trays; 
           [0025]      FIG. 8  is a front perspective view of an exhaust elbow with a flange connection; 
           [0026]      FIG. 9  is a front perspective view of a hold down clamp; 
           [0027]      FIG. 10  is a front perspective view of a jacket water supply piping with a “dry break” or “double shut-off” coupling; 
           [0028]      FIG. 11  is a front perspective view of a jacket water return piping with a “dry break” or “double shut-off coupling” which mates with the coupling of  FIG. 10 ; 
           [0029]      FIG. 12  is a front perspective view of an intercooler assembly; 
           [0030]      FIG. 13  is a front perspective view of a charged-air outpipe for connection to the intercooler of  FIG. 12  having a Bradford connection; 
           [0031]      FIG. 14  is a front perspective view of a charged-air inpipe for connection to the intercooler of  FIG. 12  having a Bradford connection; 
           [0032]      FIG. 15A  is a schematic representation of a test cell including the first engine, the first set of engine mounts, an intercooler, and a first set of charged air pipes; 
           [0033]      FIG. 15B  is a schematic representation of a test cell including the second engine, the second set of engine mounts, the intercooler, and a second set of charged air pipes; and 
           [0034]      FIG. 16  is a front perspective view of a drive shaft connection. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    Referring now to  FIGS. 1A-1B , schematic representations of a test cell, indicated generally at  10 , are provided. The test cell  10  is configured for receiving an engine  12  on a plurality of engine stands  14 , each preferably spaced a distance apart. In the preferred embodiment, four engine stands  14  are used, however it is contemplated that the number may vary. The test cell  10  also includes a dynamometer  16  having a dynamometer shaft  18 , which is located in operational relationship to the engine  12 . In the test cell  10 , the engine stands  14  are located a set, predetermined distance from the dynamometer shaft  18  on the test cell floor or other substrate. As measured from the centerline C of the dynamometer shaft  18 , each of the engine stands  14  are located a distance (y′, z′). In the most preferred embodiment, at least two of the engine stands  14  are spaced equidistantly from the centerline C of the dynamometer shaft a distance z/2. 
         [0036]    According to the method of the present test cell  10 , the location of the engine stands  14  in the test cell only have to be set once, even when different engines  12  having different sizes, shapes and arrangements are placed in the test cell. The engine stands  14  are placed in the set, predetermined locations by measurement from the dynamometer shaft  18 , or alternatively, a jig can be used. After the engine stands  14  are placed in the predetermined location, they preferably remain in that location. Further, when a plurality of test cells  10  are used, the engine stands  14  are placed in the same, predetermined locations from cell to cell. 
         [0037]    By way of example, in  FIG. 1A , a first engine model  12 A having a particular size, shape and arrangement is placed in the test cell  10 . In  FIG. 1B , a second engine model  12 B having a different, size, shape or arrangement is placed in the test cell  10 . In both  FIG. 1A and 1B , the engine stands  14  are located in the same location in the test cell  10  relative to the dynamometer  14 . 
         [0038]      FIG. 1C  is a perspective view of a preferred embodiment of engine stand  14 . The engine stand  14  is preferably adjustable in the “y” or height direction. However, when the engine stands  14  are initially located in the test cell  10  at the predetermined locations (y′, z′) from the centerline C of the dynamometer shaft, the stands preferably have approximately the same height “h”. Further, in accordance with the present method, once the engine stands  14  are placed in position, the height “h” of the stand does not need to be changed, for example from engine  12 A to engine  12 B. 
         [0039]    Referring now to  FIGS. 2A-2B , schematic drawings of the test cell  10  and the engines  12 A and  12 B are provided. A centerline corresponding to the centerline of a crankshaft of the engine is indicated at C′. In the schematic view of  FIG. 2A , a first rear mount assembly and a first front mount assembly, shown schematically at  20 A and  22 A, respectively, are attached to the first engine  12 A. The rear mount assembly  20 A preferably includes a left mount portion  24 L and a right mount portion  24 R. The left and right mount portions  24 L and  24 R are each preferably attached to the engine  12  at a set, predetermined location on the engine, and also, each is in the same position relative to the crankshaft centerline C′. As measured from the centerline C′ of the crankshaft, the left mount portion  24 L and the right mount portion  24 R are preferably both located a distance z″ in the z direction. 
         [0040]    Similarly, in the schematic view of  FIG. 2B , a second front mount assembly and a second rear mount assembly, shown schematically at  20 B and  22 B, respectfully, are attached to the second engine  12 B. As measured from the centerline C′ of the crankshaft, a left mount portion  26 L and a right mount portion  26 R are each preferably located a distance z′″ in the z direction. Further, the front mount assembly  20 B is also preferably centered with respect to the crankshaft centerline C′ in the z direction. In this configuration, the front mount assemblies  22 A, B and the rear mount assemblies  20 A, B are preferably centered in the z direction with respect to the crankshaft centerline C′. 
         [0041]    As seen between  FIGS. 2A and 2B , the front mount assemblies  22 A, B and the rear mount assemblies  20 A, B are different for engines having a different size, shape or arrangement. The mount assemblies  20 ,  22  are sized, shaped and arranged to compensate for differentiations among engines  12  so that the configuration of the test cell can remain substantially constant independent of which particular type of engine is tested. 
         [0042]    Referring now to  FIGS. 3A and 3B , the mount assemblies  20 A and  22 A attach to the engine  12 A at the set, predetermined engine location, and extend to the set, predetermined location of the engine stands  14 . For each type of engine  12 , a front mount assembly  22  and a rear mount assembly  20  are customized for that particular engine so that when the mount assemblies are attached to the engine at the set, relative location to the crankshaft centerline C′, the mount assemblies will extend to the location of the engine stands  14 . In the most preferred embodiment, the left and right mount portions  24  extend from the predetermined location on the engine  12  a distance (z/2-z″) and the left and right mount portions  26  extend from the predetermined location on the engine  12  a distance (z/2-z″′). 
         [0043]    If the mount assemblies  20  and  22  are used on the appropriate engines  12  they were customized for, the centerline C′ of the dynamometer shaft and the centerline C″ of the crankshaft will be automatically aligned, which is necessary for the operation of the test cell  10 . Additionally, the location of the engine stands  14  in the test cell  10  remains the same whether you have a larger engine, such as engine  12 A, or a smaller engine, such as engine  12 B. 
         [0044]    Further, the customized mount assemblies  20 ,  22  can be attached to the engine  12  before the engine is placed in the test cell  10 . For example, if an engine model  12 A is to be changed over for an engine model  12 B, the mount assemblies  20 B,  22 B can be attached to engine  12 B while the engine  12 A is still being tested in the test cell  10 . Additionally, the mount assemblies  20 ,  22  can be used repeatedly for similar make and model engines. In other words, the mount assemblies  20 A,  22 A can be used for each engine  12 A, for example, each V-6 International Truck® Engine. It is contemplated that each test cell  10  would be provided with a set of mount assemblies  20 ,  22  in accordance with the types of engines that would be tested. Further, it is contemplated that a set of mount assemblies  20 ,  22  may be compatible with more than one specific make and model of engine  12 . 
         [0045]    Before turning to two specific embodiments of mount assemblies  20 ,  22 , it should be understood that the invention should not be limited to the particular size, shape and arrangement of the mount assemblies described below. The mount assemblies  20 ,  22  can vary in size, shape and arrangement as long as they are configured to align the centerline C′ of the crankshaft with the centerline C of the dynamometer shaft  18  without having to adjust the engine stands  14 . 
         [0046]    Referring now to  FIG. 4 , a first embodiment of rear mount assembly  20 C is shown. The rear mount assembly  20 C includes a left rear mount portion  24 CL and a right rear mount portion  24 CR attached on both sides to a flywheel housing  28 . The flywheel housing  28  is disposed on the engine  12  around the centerline C′ of the crankshaft. Preferably the mirror image of each other, the left and right rear mount portions  24 C are attached (preferably bolted) onto the flywheel housing  28  at opposing side surfaces  30 ,  32 . 
         [0047]    The left and right rear mount portions  24  preferably include a first portion  34 , a second portion  36  generally parallel to the first portion, and a third portion  38  extending between the first and second portions. Two braces  40 ,  42  are disposed at the connections of the first, second and third portions  34 ,  36 ,  38 . At the second portion  36 , a jack bracket  44  is attached (preferably bolted). 
         [0048]    Referring now to  FIGS. 4 and 1C , the jack bracket  44  includes an extension portion  46  that is received into a jack bracket tray  48 . The jack bracket tray  48  is a tray disposed on top of the engine stand  14 . A receiving structure  50  is located on the jack bracket tray  48  and is configured to receive the extension portion  46  of the jack bracket  44 . The receiving structure  50  is preferably a block  52  with a channel  54 . The channel  54  preferably includes a pin  56 , and the extension portion  46  preferably includes an aperture  58  to receive the pin. When the pin  56  is received into the aperture  58  and the extension portion  46  is nested in the channel  54 , a tool  60  is used to secure the jack bracket  44  onto the jack bracket tray  48 . 
         [0049]    The tool  60  includes a handle  62  and a head  64  with two prongs  66 . The head  64  is inserted at a generally 45-degree angle around the pin  56 . The two prongs  66  slide along the top surface of the extension portion  46  and fits within two pin detents  68 . Then, when the prongs  66  are engaged in the detents  68 , the tool  60  is rotated to be generally parallel to the jack bracket tray  48 , which locks the head  64  in the pin detents  68 , and pushes down on the extension portion  46  to force it against the jack bracket tray  48  (see  FIG. 4 ). With this single tool  60 , all mount assemblies  20 ,  22  can be secured to the engine stands. When the rear mount assembly  20 C is to be removed from the engine stand  14 , the tool  60  is removed by rotating it and withdrawing it from the pin  56 . 
         [0050]    Turning now to  FIG. 5 , a first embodiment of a front mount assembly  22 C is shown. In the preferred embodiment, the front mount assembly  22 C is a truss-like bracket that is attached (preferably by bolting) at a top indentation portion  70  to the front of the engine  12 . A truss-like structure is preferred to a solid structure to reduce weight and material costs, and to increase maneuverability. 
         [0051]    Similar to the rear mount assembly  20 C, the front mount assembly  22 C includes a jack bracket  44  with an extension portion  46  that is received in a jack bracket tray  48  of the engine stand  46 . Further, the tool  60  is used to secure the front mount assembly  22 C as described above with respect to the rear mount assembly  20 C. 
         [0052]      FIG. 6  is a second embodiment of a left and a right rear mount portion  24 DL and  24 DR, which are configured to be attached to the housing of an engine  12  that is different from the engine of the first embodiment. The left and right rear mount portions  24 D attach to the engine  12  at each side of the centerline C′ of the crankshaft. The left and right rear mount portions  24 DL and  24 DR are preferably the mirror image of each other. 
         [0053]    Similar to the first embodiment, the left and right rear mount portions  24 D preferably include a first portion  34 D, a second portion  36 D generally parallel to the first portion, and a third portion  38 D extending between the first and second portions. Two braces  40 D,  42 D are disposed at the connections of the first, second and third portions  34 D,  36 D,  38 D. At the second portion  36 D, a jack bracket  44 D is attached (preferably bolted). 
         [0054]    The second embodiment of the left and right rear mount portions  24 D differ from the corresponding first embodiment portions  24 C in the particular size, shape and arrangement of the portions  34 ,  36 ,  38 . Since different engines have different configurations, each set of mount assemblies  20 ,  22  will have a different arrangement to compensate for these differences, thereby allowing the mount assemblies to both secure the engine and extend to the predetermined location of the engine stands  14 . 
         [0055]    Turning now to  FIG. 7 , a second embodiment of a front mount assembly  22 D is shown. The front mount assembly  22 D is a truss-like bracket having a similar, but slightly different size, shape and arrangement than the assembly  22 C. The front mount assembly is also attached (preferably by bolting) at a top indentation portion  70 D to the front of the engine  12 . 
         [0056]    Both the rear mount assembly  20 D and the front mount assembly  22 D include a jack bracket  44  with an extension portion  46  that is received in a jack bracket tray  48  of the engine stand  46 . Also, the tool  60  is used to secure the second embodiment of mount assemblies  20 D,  22 D as described above with respect to the first embodiment of mount assemblies  20 C,  22 C. Thus, the tool  60  is not only used for all attachments to the engine stands  14  within a set of mount assemblies  20 ,  22 , but is used for all sets of mount assemblies. 
         [0057]    From the above description, it should be appreciated that the present engine-changeover mounting apparatus and method of using the same standardizes the alignment of the centerline of the engine C′ to the centerline C of the dynamometer shaft  18 . But in addition to aligning engines of different size, shape and arrangement on different sets of mounts, another aspect of the present test cell change-over method is that the piping connections to and from the engine are simplified. 
         [0058]    Turning now to  FIGS. 8 and 9 , an engine exhaust elbow  72  includes a face seal flange  74  for connection to the test cell piping (not shown). A hold-down clamp  76  is used to connect the face seal flange  74  to the test cell piping without the use of any additional tools. 
         [0059]      FIGS. 10 and 11  are drawings of a water jacket supply pipe  78  and a water jacket return pipe  80 , each with a “dry break” or “double shut-off” coupling  82 ,  84 , respectively. The coupling  82  on the water jacket supply pipe  78  mates with the coupling  84  on the water jacket return pipe  80 . The “dry-break” connectors allow the engine  12  to be filled and drained outside of the test cell  10 , thus saving time. 
         [0060]    Referring to  FIGS. 12-14 , an intercooler assembly  86  includes a platform  88 , a stand  90  extending generally perpendicularly from the platform, and first and second intercooler pipe arms  92 ,  94 . The first and second arms  92 ,  94  connect to a charged-air outpipe  96  and a charged-air inpipe  102  from the engine  12 . 
         [0061]    Turning now to  FIGS. 13-15 , the outpipe  96  and inpipe  102  are unique to each engine family, but regardless of the engine family, when the pipes are attached to the engine, the termination point of the pipes is in the same relative position in space so that they will always connect with the first and second intercooler arms  92 ,  94  (See  FIGS. 15A ,  15 B). By having a set of outpipes  96  and inpipes  102  for each engine family, this negates the need to use custom bend pipe or to modify each engine pipe configuration regardless of test cell or engine. 
         [0062]    As seen in  FIG. 13 , the charged-air outpipe  96  is configured for connection to the intercooler of  FIG. 12 . The charged-air outpipe  96  preferably has a Bradford connection  98  for connecting to the intercooler first arm  92 , and a barbed end  100  for connection to the engine  12 . As seen in  FIG. 14 , the charged-air inpipe  102  for connection to the second intercooler arm  94  includes a Bradford connection  104 . On the other end, the charged-air inpipe  102  has a barbed end  106  for connection to the engine  12 . The Bradford connections  98  and  104  are preferably connected to the intercooler arms  92 ,  94  with hold-down clamps  76  or cam lock connectors. 
         [0063]    Referring now to  FIG. 15A , a schematic representation of the test cell  10  including the first engine  12 A, the first set of engine mounts  20 A,  22 A, the intercooler  86 , and a first set of charged-air pipes  96 A,  102 A is shown. The charged-air outpipe  96 A terminates at point (x 1 , y 1 , z 1 ) at the connection to intercooler arm  92 , and the charged-air inpipe  102 A terminates at point (x 2 ,y 2 ,z 2 ) at the connection to intercooler arm  94 . Now, turning to  FIG. 15B , a schematic representation of the test cell includes the second engine  12 B, the second set of engine mounts  20 B,  22 B, the intercooler  86 , and a second set of charged air pipes  96 B,  102 B. The second set of charged air pipes  96 B,  102 B is different from the first set  96 A,  102 A since a different engine is being tested and further, since the Bradford connection ends  98 ,  104  preferably terminate in the same relative position. Similar to the test cell of  FIG. 15A , the charged-air outpipe  96 B terminates at point (x 1 , y 1 , z 1 ) at the connection to intercooler arm  92 , and the charged-air inpipe  102 A terminates at point (x 2 ,y 2 ,z 2 ) at the connection to intercooler arm  94 . 
         [0064]    A drive shaft connection  108  is shown in  FIG. 16 . While the conventional connection is a spicer 8 to 12 bolt smooth flange, the present drive shaft connection  108  is a 4-bolt Hirth style flange  110  having its mating half (not shown) located on the drive plate (not shown). The two halves are machined so that they can be interchanged. This allows the driveshaft to stay connected to the dynamometer  16 , and engines to be installed with the other mating half of the flange  110  prior to the engine being selected for a specific test cell  10 . The flange  110  has serrations  112  machined at approximately 70-degree angles to each other. The serrations  112  enable the two halves to be self aligning, insuring proper crankshaft centerline C′ alignment with the centerline C of the dynamometer shaft  18 . 
         [0065]    The present method of placing the engine  12  in the test cell  10  utilizes quick connect fittings for all air and liquid hoses, allowing the engine to be installed with one tool, tool  60 . Further, since the engine mount assemblies  20 ,  22  can be attached to the engines  12  before the engines are placed in the test cell  10 , the amount of time to change-over the engines is reduced. Further still, since each engine  12  to be tested has a specific, custom made set of engine mount assemblies  20 ,  22  that attach to predetermined locations on the engine, and that extend to engine stands that are located at the predetermined locations in the test cell, the engine crankshaft centerline C′ will be automatically aligned with the dynamometer shaft centerline C without having to adjust or align elements of the test cell. With this method, each test cell  10  has a standard configuration irrespective of what kind of engine is tested. 
         [0066]    While particular embodiments of the present engine test cell changeover apparatuses and methods of using the same have been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.

Technology Category: 3