Patent Publication Number: US-6338333-B1

Title: Integrated fuel delivery module for direct injection

Description:
TECHNICAL FIELD 
     This invention relates to direct injection (DI) of fuel into the combustion chambers of an internal combustion engine and, more particularly, to an integrated fuel delivery module for mounting a plurality of DI injectors and potentially other components on a direct injection gasoline or similar engine. 
     BACKGROUND OF THE INVENTION 
     The direct injection (DI) of fuel, such as gasoline, into an engine combustion chamber requires that a DI fuel injector for each cylinder of the engine be mounted in the engine cylinder head or other combustion chamber defining member. The tip or nozzle end of the injector is directly exposed to high combustion pressures periodically occurring in the combustion chamber, and so a positive load must be applied to the injector to hold it in place and ensure that it remains sealed against leakage of exhaust gases from the combustion chamber. 
     In the past, this has been accomplished by fastening a tab or clamp on the injector directly to the cylinder head or other component. However, this requires that each injector be individually mounted to the cylinder head and adds to the manual labor cost in assembly of the engine. 
     SUMMARY OF THE INVENTION 
     The present invention solves this problem by providing an integrated fuel delivery module in which all the injectors intended for mounting in one bank of a multi-cylinder engine are installed prior to assembly. Fastening means are provided for mounting the module directly to the engine cylinder head or other combustion chamber defining component. The module includes fuel passages and may include related controls and features involved in fuel delivery to the engine. Loading springs are provided to apply a load between the inlet ends of the injectors and abutments in the body of the module so that the injectors are properly seated against their respective sealing surfaces with an adequate but not excessive load. 
     If desired, the module may comprise a portion of an intake manifold including air intake passages, exhaust gas recirculation passages and coolant passages with suitable controls for regulating EGR flow, as well as the fuel pressure delivered to the injectors. 
     These and other features and advantages of the invention will be more fully understood from the following description of certain specific embodiments of the invention taken together with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a fragmentary cross-sectional view through a portion of an engine assembly mounting an integrated fuel delivery module according to the invention; 
     FIG. 2 is a pictorial view of the module of FIG. 1; 
     FIG. 3 is an enlarged cross-sectional view illustrating a first embodiment of loading spring for the module of FIGS. 1 and 2; 
     FIG. 4 is a cross-sectional view similar to FIG. 3 but showing an alternative embodiment of loading spring; 
     FIG. 5 is a pictorial view of an alternative embodiment of integrated fuel delivery module forming an extension of an air intake manifold; 
     FIG. 6 is a pictorial view, partially in cross section, showing EGR passages in the module of FIG. 5; 
     FIG. 7 is a cross-sectional view of a module similar to that of FIGS. 5 and 6 and showing the placement of one of the injectors therein; 
     FIG. 8 is a cross-sectional view illustrating one embodiment of loading spring assembly for the injectors; 
     FIG. 9 is a view like FIG. 8 showing an alternative embodiment of injector loading spring assembly; 
     FIG. 10 is a view like FIGS. 8 and 9 showing still another embodiment of injector loading spring assembly; and 
     FIG. 11 is a pictorial view, partially in cross section, illustrating a different form of injector loading spring. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring first to FIG. 1 of the drawings in detail, numeral  10  generally indicates a portion of an engine assembly for a direct injection internal combustion gasoline engine. Assembly  10  includes a cylinder head  12  to which is directly mounted a first embodiment of integrated fuel delivery module  14 , also illustrated in FIG.  2 . 
     As seen in FIG. 1, the cylinder head  12  includes a generally cylindrical injector mounting recess  16  for each cylinder of the engine. Recess  16  is stepped down to provide axially spaced alternate seats  18 ,  20  and terminates in a smaller bore  22  that opens directly to the engine combustion chamber  24 . 
     The fuel delivery module  14 , shown in FIGS. 1 and 2, includes a body  26  having fastener bosses  28  receiving screws  30  for securing the module against mounting surfaces  32  of the cylinder head. Module  14  further includes a fuel rail  34  having a common fuel inlet passage  36  extending longitudinally in the body. A fuel inlet fitting  38  is mounted at one end of passage  36  and a fuel pressure regulator  40  is mounted at the other end. A fuel return fitting  42  is also provided adjacent the pressure regulator end of the fuel rail and a fuel pressure sensor  44  connects with the inlet passage  36  intermediate its ends. At equally spaced locations along the length of the fuel rail, there are laterally extending tubular portions  46  on which the previously mentioned mounting bosses  28  are located. The tubular portions  46  define laterally extending feeder passages  48  connecting the common inlet passage  36  with mounting recesses  50 . 
     In each of the recesses  50 , the inlet end  52  of a DI fuel injector  54  is received. Each injector  54  also includes an electrical connector  56  which extends outside the cylinder head for access, and a generally cylindrical lower end  58 , that is received in the cylinder head recess  16  of an associated cylinder. Each injector includes a sealing surface  60  or  62  which engages one of the seats  18 ,  20  upon installation in its cylinder head recess  16  to prevent leakage of gas from the engine combustion chamber. A nozzle end  64  of each injector extends into its respective bore  22  for spraying fuel into the associated engine combustion chamber  24 . At the inlet end  52  of each injector, an O-ring or other suitable seal  66  is provided to prevent leakage of fuel from the mounting recess in which the injector inlet is received. 
     For loading the injectors with an adequate force against the seat  18  or  20 , some form of spring loading is required between the inlet end  52  of each injector and an annular abutment  68  at the inner end of the mounting recess  50 . In the embodiment shown in FIGS. 1 and 3, these springs take the form of a disk or Belleville type spring  70  that engages a hardened washer  72  seated against the abutment  68 . Spring  70  also engages a second guided washer  74  having a peripheral outer flange  76  for centering the washer on the inlet end of the injector and an upstanding inner flange  78  which centers the disk spring  70  on the washer  74 . 
     Referring now to FIG. 4, wherein like numerals indicate like parts, there is shown an alternative form of loading spring  80  which includes an annular generally C-shaped body  82  for directly engaging both the abutment  68  and the inlet end  52  of the injector. A depending flange  84  surrounds the inlet end of the injector for centering the spring properly thereon. In other details, the assembly is similar to that of FIGS. 1 and 3. 
     Referring now to FIGS. 5-7 of the drawings, there is shown an alternative form of integrated fuel delivery module, generally indicated by numeral  86 . Module  86  includes a body  87  with a mounting flange  88 . Bolts  89  are provided for mounting the module on an associated engine cylinder head, not shown. As in the module embodiment previously described, the body  87  includes a fuel rail  90 . Internally, the fuel rail defines a common fuel inlet passage  91  extending from an inlet fitting  92  at one end of the fuel rail to a fuel pressure regulator  94  mounted at the other end. A fuel return passage may also be provided, if desired. The common fuel inlet passage  90  connects at equally spaced intervals with feeder passages  96 . Each of the passages  96  connects with a mounting recess  98  in which the inlet end  100  of a DI fuel injector  102  is received. 
     Injector  102  includes a compression seal surface  104  adjacent its nozzle end  106 . An alternative seal surface  108 , spaced further away from the nozzle end  106  may also be provided. As in the previous embodiment, injector  102  includes an O-ring seal  110  adjacent its inlet end, and has a loading spring assembly  112  engaging the inlet end of the injector and to be subsequently further described. As before, the injector is provided with an electrical connector  114  positioned for access from the exterior of the engine. The spring assembly  112  provides the necessary axial force on the injector to seat the injector fully in a respective recess, not shown, in the engine cylinder head and to prevent the injector from being moved by combustion chamber pressures existing in the engine cylinders. 
     In addition to the features described, which are similar to those of the previously described embodiment, module  86  additionally comprises an intermediate component mountable between the engine and an associated inlet manifold. The module  86  accordingly includes inlet air passages  116  which enter the body  87  through a surface  118  that is mountable to the inlet manifold. The air passages  116  then divide into separate legs, passing around the position of the associated fuel injector and through a surface  120  provided for mounting the module  86  to the cylinder head of the associated engine. 
     The integrated module  86  further includes an exhaust gas recirculation (EGR) valve  122  which connects with an internal EGR inlet passage  124  for providing exhaust gas to the valve  122 . The valve controls EGR flow to a common EGR passage  126  which connects through metering orifices  128  with each, or every other, branch of the associated air intake passages  116 . A coolant inlet passage  130  is also provided which conducts coolant around the base of the EGR valve to control its temperature and then directs it out through a tube fitting  132  for connection to another component or return to the cooling system. 
     FIGS. 8-10 disclose various embodiments of spring assemblies intended for use with module  86 . Spring assembly  112 , shown in FIG. 8, includes a tubular guide  134  that extends downward into the inlet bore of the associated injector  106  and upward into the associated feeder passage  96 . Guide  134  includes a radially extending flange  136  which seats against the inlet end  100  of the injector and is engaged by a disk spring  138 . A flat washer  140  is seated against an annular abutment  142  at the end of the mounting recess  98  to protect the abutment surface against wear. When the module  86  is installed, the disk spring  138  is partially compressed, loading the injector with a force sufficient to maintain seating of the injector against its seals and seal surfaces irrespective of cylinder pressures occurring in the engine combustion chamber. 
     FIG. 9 illustrates a slightly modified embodiment of spring assembly  144 . Assembly  144  also includes a tubular guide  146  which extends downward into the inlet bore of the associated injector  106  and upward into the feed passage  96  of the associated fuel rail. In this version, the guide  146  has a radially extending annular flange  148  located so as to engage the associate abutment  142  of the mounting recess  98 . A disk spring  138  engages the flange  148  and also bears against a flat washer  140  seated against the inlet end  100  of the injector. 
     Referring now to FIG. 10, a slightly different arrangement of spring  150  includes a guide  151  with a radially extending flange  152  connecting with a tubular portion  154  that extends only downward into the inlet bore of the associated injector  102 . Flange  152  is engaged by a disk spring  138  which also directly engages the inlet end  100  of the associated injector. In all of these embodiments, an O-ring seal  110  is provided for sealing the connection against loss of fuel. 
     FIG. 11 illustrates still another embodiment, wherein a single configured spring is provided for engagement with both the abutment  142  and the inlet end  100  of the associated injector. Spring  156  is formed with a C-shaped cross section and outwardly extending end flanges  158 ,  160 . A curved portion  162  interconnecting the flanges is broken by spaced openings  164  which allow the individual elements of the curved portion  162  to provide controlled flexing and loading within a required range required. Thus, the injector is seated with a load between a minimum value necessary to seal the injector/combustion chamber interface properly and a maximum value limiting loading of the injector body itself. 
     Thus the invention provides a fuel delivery module which integrates a fuel rail with its associated connections, features and components, with the injectors for one bank of a direct injection engine. When the module is secured to the engine, loading springs between the inlet ends of the injectors and abutments in the mounting recesses accommodate variations in manufacturing and assembly tolerances to provide adequate but not excessive loading of the injectors against associated seal surfaces. Manufacturing and assembly costs are reduced by the use a module with injectors pre-installed. Also, the assembly may be pretested in a suitable test fixture prior to installation to assure proper flow and spray development from each of the injectors. As noted, the module may integrate other components also, such as intake air passages, EGR passages and coolant passages and their associated components. 
     While the invention has been described by reference to certain preferred embodiments, it should be understood that numerous changes could be made within the spirit and scope of the inventive concepts described. Accordingly it is intended that the invention not be limited to the disclosed embodiments, but that it have the full scope permitted by the language of the following claims.