Abstract:
A spark plug provided to ignite fire and generate power for an engine, comprises an outer layer with an inner cavity and a ceramics insulator enclosing a central electrode inside the inner cavity. A gap is located between the ceramics insulator and the housing. The central electrode has a body and a head. One end of the body radically extends and forms a tip. The present invention improves ignition and fuel efficiency, thereby reducing air pollution.

Description:
[0001]     This application claims priority based on a Taiwanese patent application No. 094130040 filed on Sep. 2, 2005.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a spark plug. Specially, the present invention relates to a spark plug that improves the efficiency in motors.  
         [0004]     2. Description of the Relative Art  
         [0005]      FIG. 1  shows a prior art spark plug  1 . A ceramics insulator  4  encloses a central electrode  2  to prevent a high-voltage short circuit or electric leakage. Between the ceramics insulator  4  and housing  3  there are asbestos, ceramic powder filing and copper ring, wherein the ceramics insulator  4  is inserted in the housing  3  to form a gas-proof body for preventing engine&#39;s pressure leakage. Two ring-shaped auxiliary electrodes  51  and  52  are disposed on the ceramics insulator  4  wherein the outer peripheral rim  501  of the first upper ring-shaped auxiliary electrode  51  is lower than the end of the central electrode  201 . The lower peripheral rim of the ring-shaped electrode  52  is in the same height with top  301  of housing  3  in the vertical direction.  
         [0006]     As shown in  FIG. 2 , triple-spark discharges x, y, and z occur in the combustion chamber  9  of the engine  7 . Spark x is generated between the central-electrode  2  and the outer peripheral rim  501  of the first ring-shaped electrode  51 ; spark y is generated between the first ring-shaped electrode  51  and the second ring-shaped electrode; spark z is generated between the second ring-shaped electrode  52  and the housing  3 . Particularly, the tapering tip of the cylindrical ceramics insulator enables spark dischargers x and y to occur in curve lines, wherein spark discharge z occurs horizontally.  
         [0007]     However, a curviform spark discharge substantially reduces the ignition efficiency. Particularly, when the engine  7  operates at a high speed, the time for inflammable mixture entering a combustion chamber  9  is extremely short. A curviform spark discharge provided by conventional spark plug needs more time to ignite a fuel-air mixture, more than a straight line spark discharge does. It results in slow ignition and incomplete combustion. In other words, some fuel is exhausted before complete combustion; it causes not only a waste, but also air pollution.  
         [0008]     Moreover, fuel-air and greasy filth easily get into recess  6  and effect the ignition of spark discharge z. It causes a circuit-short of the spark plug and incomplete combustion.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention relates to a spark plug, wherein all spark discharges occur along a shortest straight path.  
         [0010]     The object of the present invention is to provide a central electrode that has a body and a conical head. The conical head radially extends from one end of the body.  
         [0011]     Another objective of the present invention is to provide at least one rotatable auxiliary electrode for not only igniting spark discharges more efficiently, but also extending the life span of a spark plug by slowing the oxidization rate.  
         [0012]     Another objective of the present invention is to generate at least one circular spark of 360 degrees.  
         [0013]     Another objective of the present invention is to increase the ignition efficiency and optimize the fuel efficiency. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a cross-sectional view of a prior art device;  
         [0015]      FIG. 2  shows a prior art device of  FIG. 1  Igniting sparks in an engine combustion chamber;  
         [0016]      FIG. 3   a  shows the first embodiment of the present invention;  
         [0017]      FIG. 3   b  showing has well arranged of multi holes disposed on the inclined surface of the  FIG. 3   a;    
         [0018]      FIG. 4  is a partial cross-sectional view of the first embodiment of the present invention;  
         [0019]      FIG. 5  shows the second embodiment of the present invention;  
         [0020]      FIG. 6  is a partial cross-sectional view of the second embodiment of the present invention;  
         [0021]      FIG. 7  shows the third embodiment of the present invention;  
         [0022]      FIG. 8  is a partial three-D cross-sectional view of the third embodiment of the present invention;  
         [0023]      FIG. 9  shows the airflow when a fuel-air mixture enters the engine combustion chamber with the spark plug of  FIG. 3  installed in;  
         [0024]      FIG. 10  shows the airflow of the fuel-air mixture when an engine compresses;  
         [0025]      FIG. 11  shows the spark plug of  FIG. 5  installed in an engine combustion chamber;  
         [0026]      FIG. 12  shows the spark plug of  FIG. 7  installed in an engine combustion chamber;  
         [0027]      FIG. 13  shows an embodiment of the present invention; and  
         [0028]      FIG. 14  shows another embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0029]     The preferred embodiments of the present invention are illustrated hereunder with attached drawings.  
         [0030]     Please refer to  FIG. 3   a,    FIG. 3   b  and  FIG. 4 , which show the first embodiment of the present invention. The spark plug  10  of the present invention comprises a housing  12 , a ceramics insulator  14  and a central electrode  16 . The housing  12  has an inner cavity  103  disposed within it and threads  102  on the upper part of the housing  12  for assembling into the engine block. The size of the ceramics insulator  14  varies with different pitch gauges of threads  102 . The ceramics insulator  14  encloses a central electrode  16  and is disposed in the inner cavity  103 . A gap  104  is formed between the inner cavity  103  and the housing  12 . The central electrode  16  has a body  161  and a head  162 , the head  162  radially extends from one end of the body  161 , and the outer surface of the head  162  is formed with a taper. The central electrode  16  of the first embodiment is integrated formed. The head  162  preferably is conical in shape and radially extends over the ceramics insulator  14 . In other words, the diameter of the head  162  is larger than the outer diameter of the ceramics insulator  14 .  
         [0031]     The end of the ceramics insulator  14 , which is in contact with the head  162  of the central electrode  16 , is higher than the rim  122  of housing  12 . In other words, the end of the ceramics insulator  14  is exposed from the rim  122  of housing  12 . The housing  12  tapers off to rim  122  and forms an inclined surface  121 . The inclined surface  121  has multi designed of holes  125 , and the holes  125  further have a path  127  passes through the housing  12  to the gap  104 . As shown In  FIG. 3   b,  the designed holes  125  are preferably have eight holes. But in the other embodiment, the designed holes also have at least one hole. When the fuel-air mixture to rich or the greasy filth enters into the gap  104 , they can be able to escape from the gap  104  via the designed of the holes  125  and the paths  127 . Hence the discharge of the spark plug  10  will not short circuit by the influence of the fuel-air mixture and will extend the spark plug  10  life-span.  
         [0032]     Furthermore, the inclined surface  121  helps to direct a flow direction of the fuel-air mixture. As shown in  FIG. 9 , the inclined surface  121  of the spark plug  10  is exposed in an engine combustion chamber  19 . When fuel-air mixture enters into the engine combustion chamber  19 , the inclined surface  121  directs the fuel-air mixture to contact with the spark discharge speeding up an ignition process. In this embodiment, the preferred incline angle of the inclined surface  121  is between 10 degrees to 70 degrees, wherein the most preferred incline angle is at 45 degrees. Because the 45 degrees provides the shortest travel distance to make the least energy consumption compares with all others angle of arrangement. Furthermore rim  122  and a closest portion of said central electrode  16  together define a continuous circular surface. A circular spark  105  is generated by the spark plug  10  in said continuous circular surface as shown in  FIG. 10 . In this embodiment, the preferred inclined angle of the circular surface  121  is similar to the inclined angle of the inclined surface  121 .  
         [0033]     Please refer to  FIG. 5  and  FIG. 6 , which show the second embodiment of the present invention provided to separately generate three circular sparks. The spark plug  20  comprises a housing  20 , a ceramics insulator  24  and two auxiliary ring-shaped electrodes  23 . Wherein the housing  20  has an inner cavity  203  disposed within it and threads  102  on the lower part of the housing  20  for assembling into the engine block. The size of the ceramics insulator  24  varies with different pitch gauges of the threads  202 . The ceramics insulator  24  encloses a central electrode  26 . Two depressions  241  are formed on the protruding end of the ceramics insulator  24 . The ceramics insulator  24  is disposed in the inner cavity  204 , and a gap  204  is formed between the housing  22  and the ceramics insulator  24 . The central electrode  26  has a body  261  and a head  262 . The head  262  radially extends from one end of the body  261 , and the outer surface of the head  262  is preferably formed with a taper. The central electrode  26  of this embodiment is preferred to be interatedly formed, and the head  262  is preferred conical in shape.  
         [0034]     Auxiliary ring-shaped electrodes  23  are rotatively disposed in depressions  241 . The second auxiliary ring-shaped electrode  232  is exposed from the housing  22 . The first and second ring-shaped electrodes  231  and  232  equally divide the portion of the ceramics insulator  24  exposed from the housing. Therefore spans of the three circular sparks are substantially identical. The conical head  262  radially extends over the lower end of the ceramics insulator  24 . In other words, the diameter of the base of the head  262  is larger than the outer diameter of the lower end of the ceramics insulator  24 . Furthermore, the diameters of the auxiliary ring-shaped electrodes  231  and  232  are larger than the outer diameter of the lower end of the ceramics insulator  24 .  
         [0035]     In addition, the two auxiliary ring-shaped electrodes  231  and  232  reduce an accumulation of greasy filth and thereby extend the useful life of the spark plug  20 . During the operation of the engine  17 , such as the reciprocating motion of the piston  18 , the fuel-air mixture enters into the engine combustion chamber  19  rapidly, and the operation creates a powerful airflow. The powerful airflow forces the auxiliary ring-shaped electrodes  231  and  232  to rotate around the axis of the ceramics insulator  24 . The centrifugal force of the rotation throws the greasy filth away from the auxiliary ring-shaped electrodes  231  and  232  to improve the durability of the spark plug  20 . Furthermore, the auxiliary ring-shaped electrodes  23  have a pattern  235  on its surface to form an increased effective area for receiving wind. Therefore, the increased effective area makes the rotation of the two auxiliary ring-shaped electrodes  231  and  232  easier. The pattern  235  includes a straight pattern, twill pattern  235  and cross twill  335  (as shown in  FIG. 5  and  FIG. 7 ). The pattern is designed according to different demand.  
         [0036]     The occurrences of the spark discharges of this embodiment are illustrated hereinafter accompanying with  FIG. 11 . The first and second auxiliary ring-shaped electrodes  231  and  232  generate three circular sparks, the first circular spark C  205 , the second circular spark D  206  and the third circular spark E  207 . According to a point discharge phenomenon of electricity, circular spark C  205  occurs along a shortest path between the lower peripheral rim of electrode  231  and the central electrode  26 . Circular spark D  206  occurs along the shortest path between the first electrode  231  and the second electrode  232 . Circular spark E  207  occurs along a shortest path between the upper peripheral rim of electrode  232  and the housing  22 . As we know, the shortest path preferably intersects the horizontal with an acute angle of 45 degrees. Because the 45 degrees provides the shortest travel distance that makes the least energy consumption compares with all others angle of arrangement that shows in embodiment, however, the intersection angle may vary between 10 degrees to 70 degrees. The design of the present invention enables a faster ignition, increases fuel efficiency and optimizes the ignition efficiency, thereby reduces the air pollution.  
         [0037]     A third embodiment of the present invention generates two circular sparks, as shown in  FIG. 7  and  FIG. 8 . The structure of the third embodiment resembles the second embodiment; the only difference is that the third embodiment has only one auxiliary ring-shaped electrode  33 . Please refer to  FIG. 12 ; the single auxiliary electrode  33  generates two circular sparks, spark A  305  and spark B  306 . Circular spark A  305  occurs along a shortest path between the lower peripheral rim of the auxiliary ring-shaped electrode  33  and the central electrode  36 . Circular spark B  306  occurs along a shortest path between the upper peripheral rim of the auxiliary ring-shaped electrode  33  and the housing  32 . The shortest paths mentioned above are straight lines. The shortest path where circular spark  306  occurs preferably intersects the horizontal with an acute angle of 45 degrees. In different embodiments, however, the intersection angle may vary between 10 degrees to 70 degrees.  
         [0038]     A fourth embodiment of the present invention is illustrated hereinafter accompanying with  FIG. 13 . The spark plug  40  comprises an electrically and thermally conductive housing  42 , a ceramics insulator  44  and a single auxiliary ring-shaped electrode  43 . The conductive housing  42  has an inner cavity  403  disposed within it and threads  402  on its lower part for assembling into the engine block. The size of the ceramics insulator  44  varies with different pitch gauges provided by threads  402 . The central electrode  46  disposed inside the inner cavity  403  of the ceramics insulator  44 . The depression  441  is formed on the protruding end of the ceramics insulator  44  and a gap  204  is formed between the housing  42  and the ceramics insulator  44 . Auxiliary ring-shaped electrode  43  is rotatively disposed in depression  441 . Wherein the auxiliary ring-shaped electrode  43  is exposed from the housing  42 .  
         [0039]     In this embodiment, the central electrode  46  has a stick shape. Auxiliary ring-shaped electrode  43  is rotatively disposed in depression  441 . The diameter of auxiliary ring-shaped electrode  43  is larger than the outer diameter of the lower end of the ceramics insulator  44  for a quicker ignition between the auxiliary electrode  43  and housing  42  and between electrode  43  and the central auxiliary electrode  46 .  
         [0040]     Although the preferred embodiments of the present invention have been described herein, the above description is merely illustrative. Further modification of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the appended claims. This embodiment provides two circular sparks  405  and  406  as shown in  FIG. 13 . The two circular sparks respectively intersect the horizontal with specific angles, and the range of the specific angles is between 10 degrees to 70 degrees. Similar to the first three embodiments mentioned above, the most preferred angle is at 45 degrees.  
         [0041]     Another embodiment shown in  FIG. 14  comes from the fourth embodiment by adding one auxiliary ring-shaped electrode. The central electrode is in a stick shape, the spark plug  50  generates three 360-degree circular sparks  505 ,  506  and  507 . Otherwise the features of this embodiment are similar to the second and the forth embodiments. This embodiment may include either single auxiliary  43  or two auxiliary electrodes  53 . Each of the auxiliary electrodes may have a pattern on its surface.  
         [0042]     The preferred material of the auxiliary electrodes of the embodiment 1˜5 is “Ti alloy”, and the preferred material of the central electrodes is “Ni—Fe alloy” or other innovative material. The housing is made of Fe or other electrically or thermally conductive material.  
         [0043]     Although the preferred embodiments of the present invention have been described herein, the above description is merely illustrative. Further modification of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the appended claims.