Patent Publication Number: US-6901918-B2

Title: Engine carburetor freeze-proof apparatus

Description:
BACKGROUND OF THE INVENTION 
   (a) Technical Field of the Invention 
   The present invention is related to an engine carburetor freeze-proof apparatus, and more particularly, to one provided with a pipe to connect the engine to the carburetor for conducting the combustion blow-by into the carburetor to prevent the carburetor from becoming iced-up in winter. 
   (b) Description of the Prior Art 
   As illustrated in  FIG. 1  of the accompanying drawings, a carburetor  1  of the prior art includes an air inlet  11 , a needle valve  12  and a float chamber  13 . The air inlet  11  is connected through an air filter (not illustrated); one end of the needle valve  12  is connected to the air inlet  11  and another end is located in the float chamber  13 ; and the fuel in the float chamber  13  must retain a certain level for the carburetor  1  to conduct evaporation. When the carburetor  1  operates, the needle valve  12  is driven by a piston  14  to spray fuel, and the fresh air introduced by the air filter enters into the air inlet  11  to evaporate the fuel ejected from the needle valve  12  and the mixture is imported into the engine for explosion to produce power to push the piston in the cylinder to conduct reciprocal movements at high speed for the engine to operate. 
   However, during winter time or in freezing temperatures, the wall where the air inlet  11  of the carburetor  1  contacts the piston  14  is prone to icing up resulting in the failure of the needle valve  12 , and further in the prevention of the return of fuel or engine stalling; consequently, the engine is prevented from operating normally. As illustrated in  FIG. 2 , a freeze-proof apparatus of the prior art is provided with an external hold  21  over the carburetor  2  and two pipes  31 ,  32  are connected to the hood  21  via a belt transmission  3 . When an air filter  4  delivers fresh air to the carburetor  2  for the engine to drive the belt transmission  3 , heat generated from the belt transmission  3  at high speed flows into the hood  21  of the carburetor  2  through the pipe  31  as illustrated in FIG.  3 . Accordingly, the air heated in the carburetor  2  flows back through the pipe  32  into the belt transmission  3  to complete a cycle to keep the carburetor  2  from being frozen. However, the adaptation of the hood  21  not only increases the production cost but also consumes the space in the peripheral of the carburetor  2 , resulting in difficulties in the arrangement of member parts of the vehicle in the design of the body and making the demand on the capacity of the engine higher. 
   SUMMARY OF THE INVENTION 
   The primary purpose of the present invention is to provide a compact freeze-proof apparatus for the carburetor of the engine that lowers the production cost and minimizes the impacts upon the arrangement of member parts of the vehicle caused by the presence of the freeze-proof apparatus. To achieve the purpose, a pipe is provided to the engine to connect an air heater joint of the carburetor to transfer the engine blow-by containing heat generated in the engine into the heating passage of the carburetor to prevent the carburetor from being frozen. 
   The foregoing object and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself all of which will become apparent to those skilled in the art the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. 
   Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of example. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view showing a carburetor of the prior art. 
       FIG. 2  is a schematic view of a carburetor freeze-proof apparatus of the prior art. 
       FIG. 3  is a schematic view showing the airflow in the carburetor freeze-proof apparatus of the prior art. 
       FIG. 4  is a schematic view showing an engine lubrication system of the present invention. 
       FIG. 5  is a schematic view showing a carburetor of the present invention. 
       FIG. 6  is a schematic view showing a preferred embodiment of the present invention. 
       FIG. 7  is a schematic view showing another preferred embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The following descriptions are of exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims. 
   Referring to  FIG. 4  for a lubrication system of an engine  5  of the present invention, the engine  5  is essentially comprised of a cylinder  51 , a crankshaft case  52 , a piston  53 , a crank  54 , an oil pump  55 , etc. Wherein, a cylinder head  511  and a cylinder head cover  512  are provided at the top of the cylinder  51 . A connecting pipe  513 , generally known as a blow-by pipe, is provided to the cylinder head cover  512 . The crank  54  is provided in the crankshaft case  52 , and lubricant  521  is filled into the crankshaft case  52 . The piston  53  is disposed in the cylinder  51  and the crankshaft  54  is connected to the piston  53  via a connecting rod  56  to convert the reciprocal movements of the piston  53  into rotation movements of the crankshaft  54 . The power generated by the crankshaft  54  drives the oil pump  55  to force delivery of lubricant  521  to member parts of the engine  5 . Once the engine  5  is started, fresh air is introduced to mix with the fuel. The air-fuel mixture is imported into the engine  5  for combustion to produce explosions to push the piston  53  to conduct reciprocal movements; thereby, the crankshaft conducts synchronous rotation as driven by the connecting rod  56  to further drive a chain  57  and the oil pump  55 . The oil pump  55  delivers lubricant  521  through a lubrication passage  551  inside the crankshaft  52  to lubricate mechanical parts in the engine  5 . The lubricant  521  then returns to the bottom of the crankshaft  52 . Whereas the running engine  5  will release its internal pressure to maintain normal operation, the blow-by produced within the engine  5  is discharged out of the engine  5  via the pipe  53  connected to the cylinder head cover. 
   Now referring to  FIGS. 5 and 6 , a freeze-proof apparatus of the present invention delivers the blow-by to a carburetor  7  via the connecting pipe  513 . An elbow joint  71  for heating and another elbow joint  72  for output are connected to the carburetor  7 . The heating joint  71  connects through the connecting pipe  513  while the output joint  72  is coupled to an outlet pipe  73  and further to an air filter  6 . When the engine  5  is started, the blow-by discharged from the cylinder head cover  512  is guided through the connecting pipe  513 , and the heating joint  71  of the carburetor  7  and enters into a heating passage  74  inside the carburetor  7 . The blow-by is then discharged through the output joint  72  of the carburetor and the output pipe  73  and reclaimed by the air filter  6  as illustrated in FIG.  6 . The blow-by relates to a fuel-air mixture at high temperature and heats up the carburetor  7  once the blow-by is guided into the carburetor  7 , thus to prevent the carburetor  7  from being frozen. Furthermore, the present invention can be applied in an integrated cylinder head. In such case, the connecting pipe  513  is directly connected to the cylinder head since the integrated cylinder is not provided with a cylinder head cover. 
     FIG. 7  shows another preferred embodiment of the present invention. Wherein, the connecting pipe  513  is provided to the crankshaft case  52 . Similarly, the connecting pipe  513  is connected to the carburetor  7  as illustrated in FIG.  5 . The heating joint  71  and the output joint  72  are also provided to the carburetor. The heating joint  71  is coupled to the pipe  513  and the output joint  72  is connected to the air filter  6  via an output pipe  73 . The running engine  5  delivers the blow-by at high temperature to the heating passage  74  inside the carburetor  7  through the connecting pipe  513  and the heating joint  71  of the carburetor  7  to heat up the carburetor  7 , thus keeping it from being frozen. The blow-by is then discharged through the output joint  72  and the output pipe  73  of the carburetor  7 , and reclaimed by the air filter  6 . 
   It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. 
   While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the spirit of the present invention.