Abstract:
An exhaust performance chamber is provided as in interstitial interfitting member or housing which mates between the conventional exhaust manifold exit and tail pipe entrance. The engine typically utilized with the exhaust performance chamber is a high frequency very small engine having a speed of about 30,000 to 35,000 revolutions per minute. Interposing the exhaust performance chamber into a conventional exhaust stream having a manifold and exhaust pipe connection requires an additional seal and perhaps a lengthened spring to complete the exhaust train starting from a standard configuration. The modular property facilitates multiple change-outs to determine the best configuration for a given engine and terrain. In a first embodiment, a chamber is provided ahead of an orifice. In a second embodiment, an expansion chamber is formed. The use of the performance chamber has been shown to increase fuel efficiency and increase low end or initial movement power performance.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to improvements in exhaust technology for internal combustion engines and more particularly to improvements in exhaust technology for small, high speed engines which result in improved efficiency and which facilitate interposition between the engine and final exhaust pipe and quick interchange.  
         BACKGROUND OF THE INVENTION  
         [0002]    The competitive remote controlled car field utilizes both one-eighth scale, one-tenth scale, and other remotely controlled cars having hydrocarbon powered engines. The engines are typically two cycle and operate with a fuel utilizing both conventional hydrocarbon fuel and mixed with a nitro based fuel. The angular speed of the engines can vary from 30,000 to 35,000 revolutions per minute. The combination of high speed, the resulting high frequency sound propagating through the exhaust stream and the relative lack of control available with glow plug ignition can make performance improvement possibilities problematic if not impossible.  
           [0003]    Low end power, or torque at low revolutions per minute is a problem with the above types of engines. The specific source of the problem has not been previously documented, and what would appear to be the more obvious possible solutions of modifying the engine design, or providing additional mechanical components have not materialized. In some cases, competitive racing will not allow complex solutions, and in other cases a complex solution may compromise other aspects of performance.  
           [0004]    Different sized engines and engine exhaust systems have combined with competitive component standardization to tend to restrict exhaust final systems simply to those which have been made available regardless of performance. Improved performance is typically had by a complete re-engineering of the entire exhaust system which has enough complexity that a change in one area would either result in repetitive production of the exhaust system, or degradation of performance by attempting to change two or more aspects at the same time.  
           [0005]    What is therefore needed is a simple device which has the ability to improve performance in a high frequency mechanical system and which results in minimum changes to the overall system construct. The needed solution should invite performance optimization by enabling quick connection and disconnection by interposition within the exhaust train.  
         SUMMARY OF THE INVENTION  
         [0006]    An exhaust performance chamber is provided as in interstitial interfitting member which mates between the conventional exhaust manifold exit and tail pipe entrance. The chamber requires an additional seal and perhaps a lengthened spring to complete the exhaust train starting from a standard configuration. In a first embodiment, a chamber is provided ahead of an orifice. In a second embodiment, an expansion chamber is formed. The use of the performance chamber has been shown to increase fuel efficiency and increase low end or initial movement power performance. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    The invention, its configuration, construction, and operation will be best further described in the following detailed description, taken in conjunction with the accompanying drawings in which:  
         [0008]    [0008]FIG. 1 is a cross sectional view of a manifold-seal-exhaust pipe combination and illustrating the solid view insertion of the performance chamber member an interfitting addition with additional seal;  
         [0009]    [0009]FIG. 2 is an end view of the performance chamber of FIG. 1 and illustrating internal and external details and a dimension identification key;  
         [0010]    [0010]FIG. 3 is a side sectional view of the performance chamber of FIG. 2, taken along line  3 - 3  and illustrating both further internal details and a further set of dimension identification keys;  
         [0011]    [0011]FIG. 4 is an end view of a second embodiment of a performance chamber and illustrating internal and external details and a dimension identification key; and  
         [0012]    [0012]FIG. 5 is a side sectional view of the performance chamber of FIG. 4, taken along line  5 - 5  and illustrating both further internal details and a further set of dimension identification keys. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]    The description and operation of the performance chamber invention will be best initiated with reference to FIG. 1 which illustrates a conventional exhaust manifold  21  in which flow is occurring as per the internal arrows. The exhaust manifold  21  is connected to an engine (not shown), and terminates at a fitting  23 . Fitting  23  may have a flange  25  with spring hook bores  27  located at points near the periphery of flange  25 . One or more springs  29  and  31  can be utilized with the spring hook bores  27 , as will be shown. Each of the springs  29  and  31  have hook ends  33 .  
         [0014]    A seal member  35  is shown has having a rim portion  37 , a cylindrical portion  39  on its external surface, and a cylindrical internal surface  41  interrupted by a radial land  43 . To the right of the seal member  35  is an exhaust pipe member  49  having a male fitting  51  and a flange  53  having spring hook bores  55  which are typically engaged by the other hook ends  33  of the hooks  29  and  31  to provide an urging force of flange  25  toward flange  53  to secure the seal member  35  in place.  
         [0015]    The components thus far described generally encompass a straight exhaust manifold  21  to exhaust pipe member  49  connection. Above in FIG. 1 with an arrow indicating an insertion point between the exhaust pipe  49  and the seal member  35  is an exhaust performance chamber  61  having an interfitting configuration for fitting which enables it to serially fit between exhaust pipe  49  and the seal member  35  with the addition of an additional seal member  63 .  
         [0016]    The external features of the exhaust performance chamber  61  include a main body  65 , a female fitting  67  for admitting a cylindrical portion  39  of one of the seal members  35  or  63 , and a male fitting  69  for insertion into the internal area of the seal members  35  or  63 .  
         [0017]    The male fitting forward of the flange  53  or main body  65  is the same and includes a main radial groove  71 . Main radial groove  71  is displaced from the flange  53  in the case of exhaust pipe member  49 , or is displaced from the main body  65 , in the case of the exhaust performance chamber  61 . As can be seen, the use of exhaust performance chamber  61  is simply had by unhooking the traditional exhaust manifold  21  from the exhaust pipe member  49  and inserting the exhaust performance chamber  61  with its additional seal member  63  in between. This configuration facilitates the user optimization of performance by enabling different sized exhaust performance chambers  61  to be inserted and removed under test conditions. It also facilitates the use of multiple exhaust performance chambers  61  for different engine loading conditions. For competitive racing, these conditions might include the speed of the track, the type of traction available and other factors.  
         [0018]    Referring to FIG. 2, a view taken from line  2 - 2  illustrates features seen in FIG. 1 and more. Exhaust performance chamber  61  is also seen as having a through opening  75  having a diameter “G” of about 0.532 inches. The outer diameter “F” of the male fitting  69  is about 0.748 inches. The outer diameter “L” of the main radial groove  71  is 0.669 inches. The overall diameter “E” of the main body  65  is about 1.127 inches. Also seen is an internal surface  77  of the female fitting  67  shown in dashed line format, and which will subsequently be shown in greater detail.  
         [0019]    Referring to FIG. 3, further detail is shown in a cross sectional view. From the through opening  75 , the exhaust performance chamber  61  is seen as having a male end  79 , leading into a cylindrical inlet chamber  81 . Cylindrical inlet chamber  81  leads to a main chamber  83 . Main chamber  83  is also cylindrical, but need not be. The dimensions of the main chamber  83  include a dimension “N1” which represents an axial length of about 0.276 inches. Main chamber  83  has a diameter shown with the dimension “N2” of about 0.984 inches. Adjacent the main chamber  83 , opposite the cylindrical inlet chamber  81 , is an orifice  85  having an opening  87  which may also be known as an orifice size. The embodiment shown in FIGS. 2 and 3, for exhaust performance chamber  61 , the opening  87  orifice size is about 0.532 inches, matching the dimension “G” of the through opening  75  of the male fitting  69 . Adjacent the side of the orifice  85  opposite from the main chamber  83  is the internal surface  77 . The internal surface  77  extends to a female end  89 .  
         [0020]    Further letter style dimension markers are given. The overall length “A” of the exhaust performance chamber  61  is about 1.102 inches. The combined length of the male fitting  69  and main body  65 , dimension “B” is about 0.768 inches with the length of the male fitting  69  indicated as dimension “C” as about 0.374 inches. The main body radius above the female fitting  67  is indicated as dimension “D” 0.091 inches. The axial length of the female fitting  67  indicated as dimension “H” and is about 0.334 inches. The width of the main radial groove  71  is indicated as dimension “I” and is about 0.157 inches. The difference in the radius of the male fitting  69  with respect to the radius of the main body  65  is indicated as dimension “J” and is about 0.2395 inches. The axial length of the main body is indicated by dimension “K” which is about 0.394 inches.  
         [0021]    Shown within and adjacent the internal surface  77  of the female fitting is a pair of dashed lines which represent the innermost diameter of the male fitting  51  of the exhaust pipe member  49 . This defines the amount of expansion along the axial flow direction which is available, and is shown by the dimension “M” and is about 0.020 inches. Also seen are radial surfaces  91  and  93 , which along with cylindrical surface  95  defines the enclosure of main chamber  83 .  
         [0022]    Referring to FIG. 4, an end view of a second embodiment of the performance exhaust chamber of the invention is seen from much the same position as the embodiment of FIG. 2. An exhaust performance chamber  101  provides an expansion but without the orifice  85  seen in FIG. 3. External features seen include a female fitting  107 , and a male fitting  109 . Male fitting  109  has a main radial groove  111 . A through opening  115  can be seen. The female fitting  107  has an internal surface  117 .  
         [0023]    The exhaust performance chamber  101  through opening  115  has a diameter “0” of about 0.532 inches. The outer diameter “P” of the male fitting  109  is about 0.748 inches. The outer diameter “Q” of the main radial groove  111  is 0.669 inches. The overall diameter “R” of the female fitting  107  shown in dashed line format, is about 1.127 inches.  
         [0024]    Referring to FIG. 5, further detail is shown in a cross sectional view. From the through opening  115 , the exhaust performance chamber  101  is seen as having a male end  119 , leading into a cylindrical inlet chamber  121 . Cylindrical inlet chamber  121  leads directly to a radial surface  125 . The radial surface  125  leads to an internal surface  127  of the female fitting  107 . The internal surface  127  extends to a female end  129 .  
         [0025]    Further letter style dimension markers are given. The overall length “S” of the exhaust performance chamber  101  is about 0.767 inches. The length of the male fitting  109  is seen at dimension “T” and is about 0.374 inches. The length of the female fitting  107  indicated as dimension “U” as about 0.393 inches. The width of the main radial groove  111  is indicated as dimension “V” and is about 0.157 inches. The thickness of the female fitting  107  is indicated by dimension “W” which is about 0.0715 inches. a dashed line  131  represents the extent to which a male fitting would cover the outer area of the radial surface  125  and leaves a radial height dimension indicated by the letter “X” of about 0.02 inches. This height difference, or amount of the radial surface  125  left represents the expansion available by use of the exhaust performance chamber  101 .  
         [0026]    Tests were performed which show improved run times for a given fuel supply indicating more efficient fuel consumption, as well as more bottom end power or torque at low engine revolutions per minute. The test was performed on four different engines, which are commercially available as R.B. concept, JP Engine, OS MAX01, and OFNA-Picco G-1. These engines will be designated with the letter combinations RB, JP, OS, AND OFNA. All test engines used the 9886 (0.086) one piece tail pipe. All engines utilized a 30% nitro fuel. Each engine was run with its own different type one-eighth scale four wheel drive remote control car.  
         [0027]    The engine size in all cases was the 0.21 cubic inch, 3.5 cc volume displacement glow plug type engine. Each car had a different driver who was told nothing about the details of the test or the exhaust performance chamber which was added to the cars&#39; exhaust system. a baseline run appears in Table 1 in which no exhaust performance chamber was utilized.  
                               TABLE 1                                   Engine   Run Time   Observed Bottom End Power                           RB   6:30   WEAK           JP   6:00   WEAK           OS   5:39   WEAK           OFNA   7:12   WEAK                      
 
         [0028]    Three different test parts of the exhaust performance chamber  61  were constructed having different volume main chambers  83 . Volumes of 2723 mm 3  (0.167 in 3 ), 1963 mm 3  (0.120 in 3 ), and 3434 mm 3  (0.210 in 3 ) were tried. The 3434 mm 3  (0.210 in 3 ) size generally appeared to show more promise and was selected as the test sample.  
         [0029]    A series of orifice sizes were selected for inclusion within the test sample, including orifice diameters of 13.15 mm (0.518 inches), 13.30 mm (0.524 inches), 13.52 mm (0.532 inches), 13.65 mm (0.536 inches), 13.80 mm (0.543 inches), 13.90 mm (0.547 inches), and 14.00 mm (0.591 inches). Of the above, only the 13.15 mm (0.518 inches), 13.30 mm (0.524 inches), 13.52 mm (0.532 inches), 13.65 mm (0.536 inches) categories of orifice within the selected test sample exhibited significant improvement. The results are shown in Table 2:  
                                   TABLE 2                                               Observed Bottom           Orifice   Engine   Run Time   End Power                           13.15   RB   8:10   WEAK               JP   7:50   WEAK               OS   8:30   WEAK               OFNA   9:05   WEAK           13.30   RB   7:52   FAIR               JP   7:40   FAIR               OS   7:59   FAIR               OFNA   8:40   FAIR           13.52   RB   7:42   GOOD               JP   7:28   GOOD               OS   7:54   GOOD               OFNA   8:36   GOOD           13.65   RB   7:10   GOOD               JP   6:51   GOOD               OS   6:31   GOOD               OFNA   7:40   GOOD                      
 
         [0030]    In addition to low end power, an engine temperature test was performed. In the case for no exhaust performance chamber, the engine temperatures rose quickly between the following maximums and minimums. RB, from 240° to 270°;JP, from 230° to 265°; OS, from 230° to 255°; and OFNA, from 230° to 255°. The temperature ranges which resulted from the use of various orifice sizes are seen in Table 3:  
                                   TABLE 2                                           Start   Finish           Orifice   Engine   Temperature   Temperature                           13.15   RB   242°   267°               JP   229°   267°               OS   225°   254°               OFNA   232°   250°           13.30   RB   246°   263°               JP   234°   269°               OS   228°   257°               OFNA   226°   251°           13.52   RB   242°   269°               JP   229°   268°               OS   230°   258°               OFNA   227°   254°           13.65   RB   240°   259°               JP   230°   250°               OS   226°   246°               OFNA   225°   240°                      
 
         [0031]    The results show that for nearly all tests, the maximum temperature or ending temperature for the test was slightly higher than for the baseline case (no exhaust performance chamber).  
         [0032]    The orifice size of 13.52 mm (0.532 inches) in diameter was picked as the most acceptable to use for general purposes, although certain track or surface conditions could take advantage of the other orifice sizes.  
         [0033]    In comparing the ratio of chamber volume to orifice size for the 3434 mm 3  chamber, a series of ratios result. a series of ratios of volume to orifice size of from about 261 to about 245 is computed, with the most desirable rations of from about 261 to about 251.6. The exhaust performance chamber of FIG. 3, as an example had an axial length of 0.276 inches and a diameter of about 0.984 inches to yield the 3434 mm 3  (0.210 in 3 ) chamber.  
         [0034]    As shown in FIG. 3, the ratio of diameter “N2” to axial length “N1” is about 3.56. As is shown in FIG. 5, the expansion from the 0.532 inch diameter cylindrical inlet chamber  121  to an effective enlargement of diameter “X” dimension of 0.02 to a new effective diameter of 0.572 translates to a diameter ratio of 1.075, and an area ratio of area of cylindrical inlet chamber  121  of 0.222 in 2  to a ratio of effective area of about 0.257 in 2  to form a ratio of 1.157, although the ratio may vary from about ten percent on either side to yield a ratio of from about 1.04 to about 1.29. The characterization in size to achieve performance is believed to be the best way to identify the complex interactions of exhaust flow for engines having such high frequency.  
         [0035]    While the present invention has been described in terms of an exhaust performance chamber, and more particularly to an interstitially placeable chamber for interfitting between an exhaust manifold and tail pipe, and in particular structures which can accomplish performance enhancing improvements by treating the exhaust flow stream, the principles contained therein are applicable to other instruments, devices, processes and structures in which performance enhancement is to be accomplished particularly in high frequency engines.  
         [0036]    Although the invention has been derived with reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, included within the patent warranted hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art.