Patent Publication Number: US-2005133009-A1

Title: Runnerless engine intake manifold having integral fuel delivery groove

Description:
FIELD OF THE INVENTION  
      This invention relates to internal combustion engines, particularly to engine air and fuel systems.  
     BACKGROUND OF THE INVENTION  
      An air system of an internal combustion engine conveys combustion air to combustion chambers where the air forms part of an air-fuel mixture that is compressed and combusted to power the engine. Combustion chambers of an in-line, reciprocating piston engine are cylinders that are cooperatively defined by a succession of parallel cylinder bores and a cylinder head that closes open ends of the cylinder bores. When such an engine has a cylinder block, the cylinder head is fastened and sealed to a face of the block containing the open cylinder bore ends. When such an engine is a wet sleeved engine, the cylinder head is fastened and sealed to the crankcase and the open ends of the sleeves that form the cylinder bores. Intake valves mounted on the cylinder head open at proper times during engine cycles to allow air that has passed through the air system to be admitted to the cylinders.  
      A fuel system of a diesel engine comprises fuel injectors that inject fuel into engine cylinders at proper times during engine cycles. Fuel under pressure may be delivered to the fuel injectors through a fuel manifold, or fuel rail, that serves multiple fuel injectors.  
      An intake manifold is a part of an engine air system that associates with a cylinder head to distribute air to the engine intake valves. Known intake manifolds comprise runners from a plenum to the intake valves of individual engine cylinders.  
      Fuel rails and intake manifolds are typically separate parts.  
     SUMMARY OF THE INVENTION  
      Briefly, the present invention relates to improvements in air and fuel delivery in an intake manifold mounted on a cylinder head in an internal combustion engine. The improvements arise through integration of certain features in the intake manifold in cooperation with its mounting on the head. Various economies and savings are obtained as a result.  
      The foregoing, along with further features and advantages of the invention, will be seen in the following disclosure of a preferred embodiment of the invention depicting the best mode contemplated at this time for carrying out the invention. This specification includes drawings, now briefly described as follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a cylinder head by itself.  
       FIG. 2  is a perspective view of the cylinder head with an associated intake manifold.  
       FIG. 3  is a perspective view of the intake manifold by itself in the direction of its interior.  
       FIG. 4  is a cross section view taken along section line  4 - 4  in  FIG. 2 , but showing a modified embodiment. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
      An internal combustion engine embodying principles of the present invention comprises a cylinder head  10  and a runnerless intake manifold  12 . When the latter is assembled to the former as in  FIGS. 2 and 4 , the two parts cooperatively define an air manifold  14  and a fuel manifold  16  for supplying air and fuel respectively to the engine cylinders (not shown) whose open ends are closed by cylinder head  10 . Head  10  is representative of a design for an in-line, six-cylinder diesel engine.  
      As can be understood from  FIGS. 1 and 2 , head  10  is shown without intake and exhaust valves for the respective cylinders, but both Figures show features of construction for accepting the valves and related mechanism for operating them.  
      Head  10  comprises a generally upright rectangular perimeter wall  20  surrounding an open space  22 . Wall  20  has a flat edge surface  18  to which a mating edge of a valve cover (not shown) fits to enclose space  22  where the valve operating mechanism is located. When head  10  is assembled into a wet sleeved engine to close the open ends of the sleeves, head  10  seals to the sleeves and crankcase. Head  10  comprises a series of tapped blind holes  24  in wall  20  via which fasteners (not shown) attach the valve cover to the head.  
      Head  10  further comprises six air ports  26  having entrances  28  in a surface  30  that continues from one of the two longer sides of wall  20  in the direction away from edge  18 . Entrances  28  are spaced apart along the length of surface  30 . Each port  26  forms a passageway that extends within head  10  from its entrance  28  to an entrance of the intake valve (or valves in the case of a multi-valve engine) of the corresponding cylinder. Plugged core clean-out holes  31  are shown in  FIG. 1 , but they do not pertain to the subject matter of this invention.  
      Head  10  further comprises six fuel ports  32  having entrances  34  in surface  30 . Entrances  34  are spaced apart along the length of surface  30  on an imaginary straight line that is spaced from the nearest edges of air port entrances  28 . Each port  32  forms a passageway that extends within head  10  from its entrance  34  to an exit that opens to the fuel inlet of a respective fuel injector (not shown) for the respective cylinder.  
      Air manifold  14  is formed by constructing intake manifold  12  to have a walled hollow interior space that is open to all air ports  26  with manifold  12  assembled to head  10 . Fasteners (not shown) pass through holes  36  in bosses in a perimeter flange  38  and are tightened in threaded holes  40  extending into head  10  from surface  30 . This forces a surface  42  of perimeter flange  38  against surface  30 , with an endless portion of a one-piece seal  44  that has been disposed between the two faces sealing around air manifold  14 . Seal  44  is only partially shown in  FIG. 3  for clarity of illustration.  
      Intake manifold  12  further comprises an air inlet  46  that is provided by a circular through-hole somewhere along the length of air manifold  14  in one of the walls enclosing the hollow interior space that forms air manifold  14 . At air inlet  46  the exterior of that wall has an attachment face  48  for attaching a part (not shown) of the air system through which air is introduced into air manifold  14 . In this way, air passing through the air system is distributed to the individual air ports  26  in head  10  without an individual runner to each air port.  
      Fuel manifold  16  is formed by constructing intake manifold  12  to have a groove  50  that runs along a portion of flange  38  in surface  42  and is open to all fuel ports  32 . With surfaces  42  and  30  being forced together by the fastening of intake manifold  12  to head  10 , another endless portion of seal  44  seals around fuel manifold  14 .  
      Fuel from a source such as a pump is introduced into fuel manifold  16  through a fuel inlet port  52  that has an entrance  51  at a fuel filter mounting pad surface  53  on the exterior of intake manifold  12 . Port  52  forms an internal passageway that extends within the wall of intake manifold  12  to intersect groove  50 . In this way, fuel passing through the fuel system is filtered by a filter (not shown) on pad surface  53 , introduced into port  52  where it is conveyed to groove  50  for distribution to the individual fuel ports  32  in head  10  without an individual runner or line to each fuel port.  
      Seal  44  fits into a groove  54  in surface  42 . The seal is a single piece having two endless portions, one of which seals around air manifold  12  and the other of which seals around fuel manifold  14 . It can be understood that in such a one-piece seal the two endless portions share a common segment of the seal between the two manifolds  12 ,  14 . Hence the layout of seal  44  matches that of groove  54 , but the groove layout also has a shunt  56  not occupied by seal  44 . In the unlikely event that seal  44  were mistakenly omitted or improperly placed before intake manifold  12  and head  10  were assembled together, shunt  56  would be effective to shunt leaking fuel away from air manifold  14 .  
       FIG. 4  is representative of a modified embodiment that has two separate seals  44 A,  44 F. Intake manifold  12  has two separate seal grooves  54 A,  54 F in surface  42 . Each seal groove  54 A,  54 F surrounds a respective one of manifolds  14 ,  16 , with each endless seal  44 A,  44 F fitting in a respective groove  54 A,  54 F. Running parallel with the long dimension of each seal groove, and between the two seal grooves, in surface  42 , is a groove that forms a shunt  56  that serves the same purpose as shunt  56  in the embodiments of  FIG. 1, 2 , and  3 . Leaking fuel from fuel manifold  16  will be carried away from air manifold  14  by shunt  56 .  
      Because only a single manifold part that delivers both fuel and air need be assembled to the head, the invention provides a number of advantages including savings in machining operations, assembly time, space, fasteners, servicing, and parts inventory. An intake manifold  12  may be fabricated by known manufacturing methods using known materials. For example, it may be fabricated by casting or molding, and subsequently finished using suitable finishing and/or machining techniques. Suitable materials include both metals and synthetics.  
      While a presently preferred embodiment of the invention has been illustrated and described, it should be appreciated that principles of the invention apply to all embodiments falling within the scope of the following claims.