Abstract:
The present invention describes an automobile exhaust pipes, and more particularly to an exhaust pipe capable of producing appropriate pressure to assist engine torque output when the engine is running at a low speed and expediting the waste gas to be discharged from an automobile when the engine is running at a high speed, so as to enhance the operating performance of automobile engines.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention generally relates to automobile exhaust pipes, and more particularly to an exhaust pipe capable of producing appropriate pressure to assist engine torque output when the engine is running at a low speed and expediting the waste gas to be discharged from an automobile when the engine is running at a high speed, so as to enhance the operating performance of automobile engines.  
         [0003]     2. Description of the Related Art  
         [0004]     In the operating principle of an automobile, an engine nebulizes a fuel and mixes the nebulized fuel with air, so as to create an explosion in a cylinder, and the pressure of expansion is converted into a rotary force to drive the wheels to rotate. The mainstream of automobiles is a 4-cylinder engine with a design of driving the pistons repeatedly to move up and down for two times. In other words, four actions including an air inhaling, a compression, an expansion, and a discharge are preformed when the engine rotates twice, and the ignition is done by electric sparks. The total volume for the pistons in the cylinders to move up and down is called exhaustion capacity, which is also an index of an engine power. In normal conditions, if the engine is running at a low speed, then the exhaust pipe will produce an appropriate discharge pressure to assist the engine torque output; and if the engine is running at a high speed, the exhaust pipe will expedite the exhaustion to enhance the engine operating performance of an automobile.  
       SUMMARY OF THE INVENTION  
       [0005]     The primary objective of the present invention is to provide an appropriate pressure to assist a low-speed torque output when the engine is running at a low speed and automatically and quickly discharge the waste gas from the exhaust pipe in split flows when the engine is running at a high speed, so as to enhance the engine operating performance. The present invention can meet both of the high-speed and low-speed requirements of an exhaust pipe.  
         [0006]     Another objective of the present invention is to achieve the effect of lowering the noise of the exhaustion, in addition to meeting the high-speed and low-speed requirements of the exhaust pipe.  
         [0007]     To achieve the foregoing objective, an automobile exhaust pipe assembly in accordance with the present invention comprises:  
         [0008]     an internal pipe, having linearly corresponding first end and second end, respectively having a plurality of overflow holes disposed on a pipe wall proximate to the first and second ends to define a first and a second overflow hole sections;  
         [0009]     a middle pipe, being a conical pipe and having a first end with a diameter larger than that of a second end, and an overflow hole disposed on the pipe wall, and the middle pipe is sheathed onto the first overflow hole section of the internal pipe, and the first end of the middle pipe faces the first end of the internal pipe, and the second end of the middle pipe is fixed onto the pipe wall of the internal pipe, and a increasingly reduced volume overflow space is defined between the conical shape of the middle pipe and the internal pipe;  
         [0010]     an external pipe, being sheathed onto the internal pipe and the middle pipe, and both ends of the external pope being fixed onto the exterior of the internal pipe by binding the pipe wall, such that one end seals the foregoing overflow space and the other end includes a second overflow hole section of the internal pipe; and  
         [0011]     a restrictor, having a first end and a second end, and the first end has a diameter larger than that of the second end, and streamline internal and external profiles are disposed along the first and second ends, and the first end of the restrictor is coupled onto the internal pipe wall and the second end faces the second end of the internal pipe. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]      FIG. 1  is a perspective view of the present invention;  
         [0013]      FIG. 2  is a cross-sectional view of the present invention;  
         [0014]      FIG. 3  is an exploded view of the present invention;  
         [0015]      FIG. 4  is a perspective view of a restrictor of the present invention;  
         [0016]      FIG. 5  is a cross-sectional view of the present invention;  
         [0017]      FIG. 6  is a cross-sectional view of the waste gas movement when an engine is running at a low speed according to the present invention; and  
         [0018]      FIG. 7  is a cross-sectional view of the waste gas movement when an engine is running at a high speed according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]     The exhaust pipe in accordance with the present invention comprises:  
         [0020]     an internal pipe  20 , as shown in  FIGS. 3 and 5 , being comprised of a first pipe section  201 , a second pipe section  202  and a third pipe section  203  coaxially coupled with each other, and the internal pipe  20  comprising linearly corresponding first end  21  and second end  22 , a plurality of overflow holes  241 ,  251  disposed on the pipe walls proximate to the first end  21  and the second end  22  to define a first and a second overflow hole sections  24 ,  25 , and a connecting pipe  261  disposed at the intersection of the first and second pipe sections  201 ,  202  as shown in the figure, and the connecting pipe  261  including a thread section  2611  at a pipe end corresponding to the second end  22  of the internal pipe  20 ;  
         [0021]     a middle pipe  30 , as shown in  FIGS. 2, 3  and  5 , being a conical pipe and having a first end  31  with a diameter larger than that of the second end  32 , an overflow hole  33  disposed on the pipe wall, and the middle pipe  30  is sheathed onto the first overflow hole section  24  of the internal pipe  20 , and the first end  31  of the middle pipe  30  faces the first end  21  of the internal pipe  20 , and the second end  32  of the middle pipe  30  is fixed onto the outside of the pipe wall of the internal pipe  20 , and an overflow space  34  with an increasingly reduced volume is defined between the conical structure of the middle pipe  30  and the internal pipe  20 ;  
         [0022]     an external pipe  40 , as shown in  FIGS. 1, 2 ,  3  and  5 , being sheathed onto the internal pipe  20  and the middle pipe  30 , and having both ends respectively fixed onto the outside of the internal pipe  20  by a binding ring pipe  401 .  402 , such that one end of the external pipe  40  seals the overflow space  34  and the other end includes the second overflow hole section  25  of the internal pipe  20 , and a sound silence material  41  (such as sound silence cotton) is filled between the external pipe  40 , the internal pipe  20 , and the middle pipe  30 ; and  
         [0023]     a restrictor  50 , as shown in  FIGS. 3, 4  and  5 , having a first end  51  and a second end  52 , and the diameter of the first end  51  is larger than that of the second end  52 , and streamline external and internal profiles  53 ,  54  are disposed along the first and second ends  51 ,  52 , and a connecting section  55  is extended coaxially from the first end  51  as shown in the figure, and the connecting section  55  includes an external thread section, and the external thread section of the connecting section  55  is coupled with the internal thread section  2611  of the connecting pipe  261 .  
         [0024]     The foregoing exhaust pipe assembly uses the first end  21  of the internal pipe  20  to fix the end of the exhaust pipe by a prior art for collecting the waste gas discharged from an automobile.  
         [0025]     In  FIG. 6 , when the engine of an automobile is running at a low speed, the exhaustion capacity is smaller and the airflow is slower. Air enters into the internal pipe  20  in the direction indicated by the arrow A in  FIG. 6 . Due to the streamline tapered internal profile  53  of the restrictor  50 , waste gases produce a pressure when passing through the restrictor  50 . The pressure of the waste gases assists the torque output when the engine is running at a low speed. When the pressure of the discharged gases is produced, some of the gases will overflow into an overflow space  34  through an overflow hole  241  of a first overflow hole section  24  of the internal pipe  20 . However, the overflow space  34  is tapered along the direction of the airflow, and the pressure is increased from one end to the other end. Therefore, the waste gas will flow from a tapered end of the overflow space  34  back into the internal pipe  20  through the overflow hole  241  of the internal pipe  20 . Since the middle pipe  30  is in a conical shape and tapered towards the direction of the airflow, the noise of the discharged gas can be suppressed. The exhaust pipe of the present invention can effectively lower the noise of the discharged gas when the engine is running at a low speed.  
         [0026]     Referring to  FIG. 7 , the exhaustion capacity and the gas flow become larger when the engine is running from a slow speed to a high speed, and thus more waste gas flows into the internal pipe  20  in the direction indicated by the arrow A. The overload of waste gas will be overflowed from an overflow hole  241  of a first overflow hole section  24  of the internal pipe  20  to the overflow space  34 , and the waste gas in the overflow space  34  further enters into a sound silence material  41  through the overflow hole  33 . The waste gas in the sound silence material  41  flows back into the internal pipe  20  through the overflow hole  251  of the second overflow hole section  25  of the internal pipe  20  and then the waste gas is discharged to the outside. It is worth to note that when there is a large quantity of waste gas in the internal pipe  20  to increase the pressure inside the pipe, some of the waste gas will automatically be discharged from a second end  22  of the internal pipe  20  through the overflow hole  241  of the internal pipe  20 , the overflow space  34 , the overflow hole  33  of the middle pipe  30 , the sound silence material  41 , and the overflow hole  251  of the second overflow hole section  25  of the internal pipe  20 . This process is an automatic split flow that speeds up the discharge of waste gas. Since the pressure of the overflow space  34  is larger in this process and the waste gas will flow back from the foregoing direction, therefore a large quantity of fast waste gas can be discharged successfully by the exhaust pipe of the present invention, so as to maximize the engine operating performance. When the waste gas flows back into the internal pipe  20  from the overflow hole  251  of the second overflow hole section  25  of the internal pipe  20 , the streamline tapered external profile  54  of the restrictor  50  will not constitute an obstacle to the flow of the waste gas, and it even guides and discharges the waste gas towards the direction of an outlet. Since the middle pipe  30  is in a conical shape and tapered in the direction of the airflow, therefore the noise produced by the discharged gas of different frequencies can be suppressed. With the sound silence material  41 , the noises of the high-speed flow can be absorbed. Therefore, the noise of the discharged gas can be lowered by the exhaust pipe of the present invention when the engine is running at a high speed.  
         [0027]     Referring to  FIGS. 6 and 7 , the overflow holes  251  of the foregoing second pipe section  202  (which is also the second overflow hole section  25 ) are distributed at the positions corresponding to the restrictor  50 . In other words, there is no overflow hole  251  at the position beyond the second pipe section  202  of the restrictor  50 . The main effect is to create a hole free pipe section  221  of the second end  22  of the internal pipe  20 , and the hole free pipe wall can suppress the sound transmission of the noise of the discharged gas. The second effect is to make use of the hole free pipe section  221  to reduce the loss of the sound silence cotton  41  since the sound silence cotton  41  is made of fiberglass that has the thermal resisting, moisture resisting, incombustibility, chemical corrosiveness resisting, mold resisting, heatproof, soundproof, and insulating features. However, the fiberglass has its weaknesses such as its fragility and poor wear resistance. If a large quantity of waste gas in the exhaust pipe of the present invention passes through the sound silence cotton  41  at a high speed, the sound silence cotton  41  will have a slight burning phenomenon caused by the collisions of a large quantity of high-temperature waste gas. Such burning phenomenon may cause the sound silence cotton  41  to fall off, and a small part of the burned sound silence cotton will together with the waste gas may enter into the internal pipe  20  through the overflow hole  251  of the second pipe section  202 . To prevent excessive losses of the sound silence cotton in the second pipe section  202  while achieving the purpose of discharging a large quantity of waste gas by split flows, the inventor of the present invention restricts the overflow holes  251  of the second pipe section  202  to the position of the restrictor  50 .  
         [0028]     A user may selectively use or remove the foregoing restrictor  50 , since the restrictor  50  comes with a thread connecting section  55  to be connected to a connecting pipe  261  of the internal pipe  20 . Such arrangement makes the assembling and removal very easy.  
         [0029]     After the restrictor  50  is removed, the internal pipe  20  is used to define a longer distance of the gas passage, so that a pressure will be produced when the waste gas passes through the internal pipe  20 . If the restrictor  50  is installed, the pressure will be larger and the time for forming the pressure will become shorter.  
         [0030]     A restrictor  50  with different diameters can be installed to the foregoing exhaust pipe of a fixed specification to fit different automobiles with different engine outputs. Thus, the present invention provides a solution of changing the exhaustion capacity of an exhaust pipe.  
         [0031]     In summation of the description above, the exhaust pipe of the present invention can produce an appropriate gas discharge pressure when the engine is running at a low speed, so at to assist the low-speed torque output, and the exhaust pipe can automatically discharge the waste gas in split flows when the engine is running at a high speed. Therefore, the present invention can meet both of the high-speed and low-speed requirements. In addition, the internal pipe  20  can isolate the noise made by the airflow of the waste gas by means of the overflow space  34 , the sound silence space  41 , and the external pipe  40 . The first end  21  and the second end  22  of the internal pipe  20  are free of holes, therefore the first end  21  and the second end  22  can further suppress the noise of the waste gas. Overall speaking, the exhaust pipe of the present invention produces very little noise for discharging the waste gas.  
         [0032]     While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.