Abstract:
Fuel injection equipment includes a high pressure fuel source able to flow high pressure fuel via connecting pipes to a plurality of injectors. The fuel injection equipment is high pressure fuel reservoir-less, a distributed storage for high pressure fuel being arranged in the pipes and in the injectors.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a national stage application under 35 USC 371 of PCT Application No. PCT/EP2014/064306 having an international filing date of Jul. 4, 2014, which is designated in the United States and which claimed the benefit of European Patent Application No. 13175394.9 filed on Jul. 5, 2013, Great Britain Patent Application No. 1317441.2 filed on Oct. 2, 2013, and Great Britain Patent Application No. 1320374.0 filed on Nov. 19, 2013, the entire disclosures each are hereby incorporated by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to rail-less high pressure fuel equipment having distributed fuel storage. 
       BACKGROUND OF THE INVENTION 
       [0003]    High pressure fluid equipment commonly stores high pressure in a common rail prior to flow to the fuel to the injectors. The rail is a large component and recent optimization of engine layout render arrangement of a rail more complex. 
         [0004]    Market demands rail-less equipment. 
       SUMMARY OF THE INVENTION 
       [0005]    Accordingly, it is an object of the present invention to provide fuel injection equipment (FIE) for an internal combustion engine. The equipment comprises a high pressure fuel source able to flow high pressure fuel via connecting pipes to a plurality of injectors. The FIE is high pressure fuel reservoir-less, a distributed storage for high pressure fuel being arranged in the pipes and in the injectors. FIE are commonly known as “common-rail” systems while the FIE of the present application has no “rail”. 
         [0006]    In a first architecture of the FIE, the injectors are all directly connected to the source, each injector having one fuel inlet. 
         [0007]    In another architecture of the FIE, the injectors are in-line connected so that they form a daisy chain, the source being connected to an injector of the line, and the injectors having two inlets. 
         [0008]    In yet another architecture, the source is connected to another injector of the line, all the injectors having two inlets. 
         [0009]    The FIE may comprise a second high pressure source connected to another injector of the line, all the injectors having two inlets. 
         [0010]    Typically, the high pressure source comprises a high pressure pump. In certain architecture the source may comprise a plurality of high pressure pumps. 
         [0011]    A FIE may comprise a plurality of pumps all connected to a union member. An alternative is that the pumps are connected in series. 
         [0012]    The invention is also related to an injector having two inlets so that it can be arranged in a FIE as previously described. The inlets outwardly extend along an axis either parallel or set at an angle, relative to the main axis of the injector. 
         [0013]    The inlets may be provided with threaded members so that the pipes can be connected via a nut. 
         [0014]    The fuel injector is able to internally withstand from to 4 to 8 cm 3  of high pressure fuel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The present invention is now described by way of example with reference to the accompanying drawings in which: 
           [0016]      FIGS. 1 to 5  are five different schematics of exemplary architectures of fuel injection equipment wherein the injectors are directly connected to the pump. 
           [0017]      FIGS. 6 to 10  are five other different schematics of exemplary architectures of fuel injection equipment wherein the injectors form a daisy chain. 
           [0018]      FIG. 11  is an axial section of an injector as per the invention. 
           [0019]      FIGS. 12 and 13  are isometric views of two different embodiments of injector heads. 
           [0020]      FIG. 14  is an exemplary embodiment of a daisy chain of injectors. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    In the following description, similar elements will be designated with the same reference numbers. 
         [0022]    An internal combustion engine  10  is provided with high pressure fuel injection equipment (FIE)  12 . 
         [0023]    Five alternative architectures of FIE  12  are now described in reference to  FIGS. 1 to 5 . 
         [0024]    A first architecture of the FIE  12  is represented in  FIG. 1 . It comprises a single high pressure pump  14 , six injectors  16  and a pressure regulator  17 , shown only in  FIG. 14 , the regulator  17  comprising a pressure sensor and a pressure valve able to open and re-route high pressure fuel toward a low pressure tank. Each of the injectors  16  is directly connected to the pump  14  via a connecting pipe  18  and, in operation the pump  14  flows high pressure fuel toward each of the injector  16 . All FIE  12  examples have six injectors  16  but the teachings of the invention can directly be applied to engines  10  having another number of injectors  16 , for instance four, five, eight, ten or more. 
         [0025]    During an injection event, the fuel expelled through the spray holes of the nozzle  22  of an injector  16  empties, inside said injector  16 , the space that is in the vicinity of the spray holes. Before the following injection event, this space is refilled with the high pressure fuel contained in the pipe  18  and inside the injector  16  itself. An internal reservoir  34 , or storage pocket, of high pressure fuel may be accommodated inside the injector for instance as detailed in application number GB 1317441.2 filed on 2 Oct. 2013. 
         [0026]    A second FIE  12  architecture is sketched in  FIG. 2 . This FIE  12  comprises two high pressure pumps  14 , each supplying fuel to a bank of three injectors  16 . Similar to the first embodiment, each injector  16  is connected directly to one of the pumps  14 . In addition, and referencing the injectors  16  “first to sixth” from the left to the right of the figure, the first, second, fifth and sixth injectors have a single inlet  20  while third and fourth injectors each have two inlets  20 . This fluid link between injectors three and four ensures balance of the pressure in the FIE so only one pressure sensor is required. 
         [0027]    A third FIE  12  is sketched in  FIG. 3 . It is similar to the second FIE architecture with the exception that no link is made between two injectors while a pipe  18  interconnects the two pumps  14 . In this third architecture, each injector  16  has a single inlet  20 . 
         [0028]    A fourth FIE  12  architecture is represented in  FIG. 4 . As can be observed it is indeed an alternative to the second architecture here above described. The fourth FIE  12  comprises three pumps  14  each directly supplying high pressure fuel to a bank of two injectors  16 . Fluid communication is made between second and third injectors and also between fourth and fifth injectors  16 . Consequently, first and sixth injectors  16  have a single inlet  20  while each other injector has two inlets  20 . 
         [0029]    A fifth FIE  12  architecture is represented in  FIG. 5 . It is similar to the fourth architecture to the exception that no link is made between injectors while a pipe  18  interconnects the pumps  14 . In this case, all the injectors  16  have a single inlet  20 . 
         [0030]    Further alternatives of FIE  12  architecture, not represented, can easily be implemented in increasing the number of pumps  14 , creating fluid links between pumps or between injectors. 
         [0031]    Five further FIE  12  architectures, referenced sixth to tenth, are now described in reference to  FIGS. 6 to 10 . In each of them the injectors  16  are connected in-line, forming a daisy chain. 
         [0032]    The FIE  12  of the sixth architecture,  FIG. 6 , comprises a single pump  14  which flows high pressure fuel to the first injector  16  of the daisy chain. Each of first to fifth injectors have two inlets  20 , only the last of the chain has a single inlet  20 . 
         [0033]    In operation, the space emptied by an injection event is quickly refilled with high pressure fuel contained in the pipes  18  connected to the injector  16  and inside the injector  16 . As previously detailed, an internal reservoir  34  or storage pocket  34  of high pressure fuel may be accommodated inside the injector for instance as detailed in application number GB1317441.2. 
         [0034]    The seventh FIE  12  architecture,  FIG. 7 , differs from the sixth architecture in that the pump  14  is connected to the first and to the last injectors  16 , the FIE  12  forming a closed loop. In this seventh architecture all the injectors  16  are provided with two inlets  20 . The seventh architecture has the advantage to easily refill all the injectors  16  of the daisy chain. 
         [0035]    The eighth FIE architecture,  FIG. 8 , comprises two pumps  14  each one being connected to one injector  16 . In the embodiment presented on the figure the first pump  14  is connected to the first injector  16  and the second pump  14  is connected to the sixth injector  16 . Here again all the injectors  16  are provided with two inlets  20 . 
         [0036]    The ninth FIE  12  architecture,  FIG. 9 , differs from the sixth architecture in that it comprises a plurality of pumps  14 ; here three pumps are represented while another number is possible. All the pumps are connected to a union member  24  from which flows fuel toward the first injector  16 . 
         [0037]    Another alternative is represented by the tenth FIE 12  architecture,  FIG. 10 , where three pumps  14  are connected in series, prior to flowing fuel toward the first injector  16 . 
         [0038]    In the ninth and tenth architectures, as in the sixth, only the last injector  16  has a single inlet  20  while the first to fifth injectors  16  have two inlets  20  each. 
         [0039]    In previously described FIE architectures it is possible to commonize the utilization of only one type of injector  16 , injectors provided with two inlets where, when needed the second inlet can be plugged for instance with a dummy short pipe. 
         [0040]    An injector  16  having two inlets  20  is now described in reference to  FIG. 11 . The injector  16  extends along a main axis Z. The upper parts of the injector  16  are not represented and, without any limiting intention in choosing the vertical top to bottom orientation of  FIG. 11 , the injector  16  comprises a core  26  arranged above the nozzle  22  within which is reciprocally arranged a needle  28  opening or closing the spray holes of the nozzle  22 . From two inlets  20 , arranged in the head  32  of the injector  16 , downwardly extend toward the nozzle  22  two high pressure channels  30 . As can be seen, the two channels  30  merge around the needle  28 , into an internal storage pocket  34  able, in operation, to quickly provide high pressure fuel to the spray holes. 
         [0041]    While GB 1317441.2 is primarily based on low and medium duty injectors, this application was first thought for heavy duty FIE which injectors may withstand 4 to 8 cm 3  of high pressure fuel. 
         [0042]    Two different embodiments of injector heads  32 , each provided with two inlets  20 , are represented on  FIGS. 12 and 13 . The inlets  20  extend along their own inlet axis I and, on the head  32  of  FIG. 12 , the inlet axes I are parallel to the main axis Z while, on the head  32  of  FIG. 13  the axes I are at an angle A relative to the main axis Z. The angle A of  FIG. 13  is approximately 45° but any other angle is possible. Multiple connecting arrangements of the pipes  18  onto the inlet  20  can be chosen, in particular the clamping connections taught in application EP13175394, now publication number EP2821630. The connection of  FIG. 13  is based on a nut bolted onto a threaded portion of the inlet  20 . 
         [0043]      FIG. 14  represents an exemplary FIE  12  comprising a daisy chain of six injectors  16 , at the end of the chain is arranged a pressure regulator  17 . 
         [0044]    The heads  32  have two inlets  20  and are similar to the head  32  of  FIG. 12 . A chain with heads  32  such as in  FIG. 13  is not represented but can also be arranged in a similar way as shown on  FIG. 14 . At the end of the chain is arranged a pressure regulator  17 .