Patent Publication Number: US-10309358-B2

Title: Fuel pressure pulsation damping device and fuel system including the same

Description:
RELATED APPLICATION 
     This application claims the benefit of Chinese Patent Application No.: CN 201611025047.9 filed on Nov. 15, 2016, the entire contents thereof being incorporated herein by reference. 
     FIELD 
     The present disclosure relates to a fuel pressure pulsation damping device and a fuel system including the same. 
     BACKGROUND 
     In a diesel engine, fuel is pressurized and supplied to a fuel rail via a high pressure pump and injected into a combustion chamber via a fuel injector. Under some circumstances, the high pressure pump is required to continuously provide fuel to the fuel rail in order to maintain a predetermined pressure in the fuel rail, and unused fuel will flow back into a fuel tank via a fuel return line from the high pressure pump. Operation of the high pressure pump may cause fuel pressure pulsation in the fuel return line, which may be excited to induce a vibration of the fuel line. In a vehicle with a diesel engine, a vibration of the fuel line may be transmitted into a vehicle body, thus causes a noise. A metallic pulsation damping box used in a conventional fuel line is expensive. Thus, there is a need for a simple and low cost fuel pressure pulsation damping device adapted for various fuel system. 
     SUMMARY 
     According to one aspect of the present disclosure, a fuel pressure pulsation damping device is provided. The damping device is located in fuel return line between a high pressure pump and fuel tank in a fuel system. The damping device includes a housing having an inlet pipe, an outlet pipe and an intermediate pipe; and a rotatory impeller positioned in the intermediate pipe. 
     In one embodiment, a cross-sectional area of the intermediate pipe is larger than a cross-sectional area of the inlet pipe and the outlet pipe. 
     In another embodiment, a radius of the intermediate pipe is three times of a radius of the inlet pipe. 
     In another embodiment, a length of the intermediate pipe is in arrange from about 12 mm to about 15 mm. 
     In another embodiment, the impeller includes a plurality of vanes having an angle relative to a cross-section of the intermediate pipe and spaced apart from each other. 
     In another embodiment, the angle of the vane relative to the cross-section of the intermediate pipe is in arrange of about ten degrees to about thirty degrees. 
     In another embodiment, a sum of an area of the plurality of vanes projecting on the cross-section of the intermediate pipe is about 60% to about 90% of a cross-sectional area of the intermediate pipe. 
     In another embodiment, the fuel pressure pulsation damping device further comprising a supporting structure integrally formed with the housing to support the plurality of vanes. 
     In another embodiment, the impeller further includes an annular portion surrounding the plurality of vanes and an outer surface of the annular portion of the impeller is spaced apart from an inner surface of the intermediate pipe. 
     In another embodiment, the supporting structure is positioned at the cross-section of the intermediate pipe, and the supporting structure is a cruciform structure. 
     In another embodiment, the impeller is connected to the supporting structure via a fastener. 
     In another embodiment, the housing includes a first housing and a second housing, and the first housing and the second housing together form the housing. 
     In another embodiment, the supporting structure includes a first supporting portion integrally formed with the first housing and a second supporting portion integrally formed with the second housing. 
     In another embodiment, the first housing and the second housing respectively form a first reinforcement rib and a second reinforcement rib adjacent to a rim thereof along a lengthwise direction and contact each other when the first housing is assembled to the second housing. 
     In another embodiment, the housing and the impeller are formed of plastic material. 
     According to another aspect of the present disclosure, a fuel supply system is provided. The fuel supply system includes a fuel tank; a high pressure pump; a supply line connecting with the fuel tank and the high pressure pump; a return line connecting with the fuel tank and the high pressure pump; and a fuel pressure pulsation damping device positioned at the return line between the high pressure pump and the fuel tank; wherein the fuel pressure pulsation damping device includes a housing having an inlet pipe, an outlet pipe and an intermediate pipe positioned between the inlet pipe and the outlet pipe; and a rotatory impeller positioned in the intermediate pipe, wherein a cross-section area of the intermediate pipe is larger than a cross-section area of the outlet pipe. 
     In one embodiment, the fuel pressure pulsation damping device is positioned closer to the high pressure pump than the fuel tank. 
     In another embodiment, the impeller includes a plurality of vanes having an angle relative to a cross-section of the intermediate pipe and spaced apart from each other. 
     In another embodiment, the angle of the vane relative to the cross-section of the intermediate pipe is between ten degrees and thirty degrees. 
     In another embodiment, the fuel supply system further comprises a supporting structure integrally formed with the housing to support the impeller. 
     In another embodiment, the impeller is connected to the supporting structure via a fastener. 
     In another embodiment, the housing includes a first housing and a second housing, and the first housing and the second housing together form the housing. 
     In another embodiment, the first housing and the second housing respectively form a first rib and a second rib adjacent to a rim thereof along a lengthwise direction and contact each other when the first housing is assembled to the second housing. 
     In another embodiment, the supporting structure includes a first supporting portion integrally formed with the first housing and a second supporting portion integrally formed with the second housing. 
     One or more advantageous features as described herein are believed to be readily apparent from the following detailed description of one or more embodiments when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Example embodiments will be more clearly understood from the following brief description taken in conjunction with the accompanying drawings. The accompanying drawings represent non-limiting, example embodiments as described herein. 
         FIG. 1  is a schematic diagram of a fuel supply system according to one embodiment of the present disclosure. 
         FIG. 2  is a perspective view of a fuel pressure pulsation damping device according to one embodiment of the present disclosure. 
         FIG. 3  is a perspective view of a part of the fuel pressure pulsation damping device along lines I-I in  FIG. 2 . 
         FIG. 4A  is a perspective view of an impeller of the fuel pressure pulsation damping device in  FIG. 3 . 
         FIG. 4B  depicts an enlarged view of a portion A of an impeller vane of the impeller in  FIG. 4A . 
         FIG. 5  depicts an exploded view of the fuel pressure pulsation damping device in  FIG. 2 . 
     
    
    
     It should be noted that these figures are intended to illustrate the general characteristics of methods, structure and/or materials utilized in certain example embodiments and to supplement the written description provided below. These drawings are not, however, to scale and may not precisely reflect the precise structural or performance characteristics of any given embodiment, and should not be interpreted as defining or limiting the range of values or properties encompassed by example embodiments. The use of similar or identical reference numbers in the various drawings is intended to indicate the presence of a similar or identical element of feature. 
     DETAILED DESCRIPTION 
     The disclosed fuel pressure pulsation damping devices and fuel systems will become better understood through review of the following detailed description in conjunction with the figures. The detailed description and figures provide merely examples of the various inventions described herein. Those skilled in the art will understand that the disclosed examples may be varied, modified, and altered without departing from the scope of the inventions described herein. Many variations are contemplated for different applications and design considerations; however, for the sake of brevity, each and every contemplated variation is not individually described, in the following detailed description. 
     Throughout the following detailed description, examples of various fuel pressure pulsation damping devices and fuel systems are provided. Related features in the examples may be identical, similar, or dissimilar in different examples. For the sake of brevity, related features will not be redundantly explained in each example. Instead, the use of related feature names will cue the reader that the feature with a related feature name may be similar to the related feature in an example explained previously. Features specific to a given example will be described in that particular example. The reader should understand that a given feature need not be the same or similar to the specific portrayal of a related feature in any given figure or example. 
       FIG. 1  is a schematic diagram of a fuel supply system  100  according to one embodiment of the present disclosure. The fuel supply system  100  may be a fuel supply system of an engine in a vehicle. In one or more embodiments, the fuel supply system  100  may be a fuel supply system of a diesel engine. The fuel supply system  100  may include a fuel tank  102 , a fuel pump  104  positioned in the fuel tank  102 , a filter  106 , a first supply line  108  connecting to the fuel pump  104  and the filter  106 , a high pressure pump  110 , a second supply line  112  connecting the filter  106  and the high pressure pump  110 , a fuel rail  114 , a third supply line  116  and a first return line  118  connecting to the high pressure pump  110  and the fuel rail  114 , and a second return line  120  connecting to the high pressure  110  and the fuel tank  102 . In some embodiments, the fuel supply system  100  may include a pressure pulsation damping device  122  positioned at the second return line  120 . In one or more embodiments, the fuel pump  104  may be a low pressure pump and provide fuel to the high pressure pump  110  via the first supply line  108  and the second supply line  112 . The fuel may be filtered by the filter  106  before entering into the high pressure  110 . The filtered fuel may be pressurized and provided to the fuel rail  114  via the third supply line  116 . In one or more embodiments, the high pressure pump  110  may be a piston pump. Under some circumstances, the high pressure pump  110  needs to operate continuously to supply fuel to fuel rail  114  in order to maintain a necessary pressure in the fuel rail  114 . Extra fuel will flow back to the high pressure pump  110  via the first return line  118  and then flow back to the fuel tank  102  via the second return line  120  when a predetermined pressure is reached in the fuel rail  114 . The operation of the high pressure pump may cause a pressure pulsation in the return line, which may result in a vibration of the fuel line relative to a vehicle body, thus a noise will be generated. A fuel pressure pulsation damping device  122  of the present disclosure is provided to damp noise caused by pressure pulsation. The fuel pressure pulsation damping device will be detailed in the following description. 
     Referring to  FIG. 2  and  FIG. 3 ,  FIG. 2  depicts a perspective view of the fuel pressure pulsation damping device  122  in  FIG. 1 .  FIG. 3  depicts a perspective view of the fuel pressure pulsation damping device  122  from a cross section along line I-I. In one or more embodiments, the fuel pressure pulsation damping device  122  may include a housing  124  and a rotatory impeller  132  positioned in an intermediate pipe  130 . The housing  124  includes an inlet pipe  126 , an outlet pipe  128  and the intermediate pipe  130  positioned between the inlet pipe  126  and the outlet pipe  128 . The inlet pipe  126  and the outlet pipe may be connected to the second return line  120  via any suitable methods. For example, the inlet pipe  126  and the outlet pipe  128  may have a thread portion to connect with the second return line  120  via a thread. In one or more embodiments, the fuel pressure pulsation damping device  122  further includes a supporting structure  134  to support the impeller  132 . The supporting structure  134  is positioned at a cross-section of the intermediate pipe  130  or a plane substantially perpendicular to the length direction L. The supporting structure  134  may include an annular ring  134  and a plurality of ribs  136  extending from the annular ring and connecting each other at a center of the cross section. An assembling hole  152  is formed on a connection portion of the ribs  136  or a center of the cross section of the supporting structure  134 . In an embodiment shown in  FIG. 3 , the supporting structure  134  has four ribs  136  passing through a diameter of a cross-section of the housing  124  and uniformly distributed along a circumferential direction, that is, the supporting structure  134  is a cruciform structure. It should be understood that the supporting structure  134  may also include three ribs  136  uniformly distributed along a circumferential direction. In one or more embodiments, the supporting structure  134  may be integrally formed with the housing  124 . For example, the supporting structure  134  may be integrally formed with the housing  124  in an injection molding process. In other embodiment the supporting structure  134  may be connected to the housing  124  via a fastener. In one or more embodiments, the impeller  132  may assembled to the supporting structure  134  by a fastener  138  via the assembling hole  152 . 
       FIG. 4A  depicts an enlarged view of the impeller  132 , and  FIG. 4B  depicts an enlarged portion A of a vane of the impeller  132 . Referring to  FIGS. 4A and 4B  and with further reference to  FIG. 3 , the impeller  132  is positioned in the intermediate pipe  130 . A diameter of the intermediate pipe  130  may be larger than a diameter of the inlet pipe  126  and a diameter of the outlet pipe  128 . Because a volume of the intermediate pipe  130  is larger than a volume of the return line for a same length, thus a kinetic energy or pressure pulsation of fuel is reduced after fuel enters into the intermediate pipe  130 . 
     The impeller  132  may further reduce pressure pulsation. The impeller  132  may include a plurality of vanes  158  and an annular portion  160  surrounding the plurality of vanes  158 . Referring to  FIGS. 4A and 4B , the vane  158  may has an angle α relative to a cross-section of the intermediate pipe  130  or relative to a plane S substantially perpendicular to the lengthwise direction and spaced apart from each other. In one or more embodiments, the vane  158  has a flat surface. In one or more embodiments, the angle α between the vane  158  and the cross-section S may be between ten degrees and thirty degrees. In one or more embodiments, a flow direction of fuel is the same as a length direction L and perpendicular to the cross-section S. The fuel entering into the intermediate pipe  130  impacts the vanes  158  and thus drives a rotation of the vanes  158 . Pulsation energy of fuel is at least partially translated into rotatory energy of the impeller  132  and the turbulence flow. Thus, noise resulted from fuel pressure pulsation may be effectively reduced. 
     The shape and the size of the impeller  158  may be configured to reduce pulsation of a specific fuel system. For example, the impeller  158  may have a curved surface or a flat surface. In one or more embodiments, an outer surface  162  of the annular portion  160  of the impeller  112  may be spaced at a range between 1 mm and 2 mm from an inner surface of the intermediate pipe  130 . In one or more embodiments, a sum of an area of the plurality of vanes  158  projecting on the cross-section S of the intermediate pipe  130  may account for 60% to 90% of a cross-sectional area of the intermediate pipe  130 . In one or more embodiments, a thickness of the vanes  158  is at a range between 15 mm and 2.5 mm. In one or more embodiments, the vanes  158  and the impeller  132  may be formed from plastic material. 
     The material of the vanes  158  may be selected to facilitate the reduction of the pulsation of specific fuel system. For example, the vanes  158  may be made from a plastic material with different stiffness. In one car more embodiments, the vanes  158  may be made from a plastic material which is difficult to be deformed. In one or more embodiments, the vane  158  may be formed of a deformable plastic material or the thickness of the vane  158  may be relative small. The vanes may be vibrated by the fuel pressure pulsation to damp the pulsation while the vibration will not cause the vibration of the vehicle body. Deformation of the vanes  158  can be controlled at a desired range by the support from the annular portion  160  of the impeller. 
     In one or more embodiments, the impeller  132  may be positioned at a cross-section of the intermediate pipe  130  adjacent to the inlet pipe  126 , or a cross-section positioned at the middle of the intermediate pipe  130 , or a cross-section of the intermediate pipe  130  adjacent to the outlet pipe  128 . The position of the impeller  132  in the intermediate pipe  130  may affect a pulsation energy conversion of the fuel entering into the intermediate pipe  130 . Thus, the position of the impeller  132  in the intermediate pipe  130  may be varied based on specific fuel system. 
     In one or more embodiments, the fuel pressure pulsation damping device  122  is positioned closer to the high pressure pump  110  than the fuel tank  102  such that the fuel pressure pulsation would be damped in advance to prevent relative high pressure pulsation from being excited in the return line  120 . 
     Referring to  FIG. 5  and  FIG. 3 ,  FIG. 5  depicts an exploded view of the fuel pressure pulsation damping device  122 . The housing  124  includes a first housing half  140  and a second housing half  142 , The first housing half  140  and the second housing half  142  extend at a lengthwise direction and opposite each other at the lengthwise direction. A cross-sectional area of the intermediate pipe  130  is larger than a cross-sectional area of the inlet pipe  126  and the outlet pipe  128 . Further, a radius R 1  of the intermediate pipe  130  is three times of a radius R 2  of the inlet pipe  126 . Such configuration may reduce fuel pressure pulsation through an expansion of the high pressure fuel when the fuel entering into the intermediate pipe  130  via the inlet pipe  126 . In one or more embodiments, a length of the intermediate pipe  130  is about 40 mm, and the radius R 1  is about 12 mm-15 mm. The first housing half  140  may be connected to the second housing half  142  via any appropriate methods such as an adhesive, a fastener or welding etc. In one or more embodiments, the supporting structure  134  includes a first supporting portion  144  integrally formed with the first housing half  140  and a second supporting portion  146  integrally formed with the second housing half  142 . The first housing half  140  and the second housing half  142  include a first reinforcement rib  148  and a second reinforcement rib  150  adjacent to a rim thereof along a length direction L respectively, which may contact each other when the first housing half  140  is assembled to the second housing half  142 . Further, the supporting structure  134  includes a mounting hole  152  to receive a fastener for example a stud  154  and a nut  156  to assemble the impeller  132  to the supporting structure  134 . In one or more embodiments, the housing  124  is formed from plastic material in an injection molding process. 
     It should be understood that the housing may be formed via other processes. For example, the housing may be blow-molded and divided into the first housing half and the second housing half at a cross-section. The first housing half may be connected to the second housing half via bonding, a fastener or welding after the impeller and the supporting structure are assembled to the first housing or the second housing. 
     In one or more embodiments, the housing and the impeller may be formed of plastic material. Accordingly, the fuel pressure pulsation damping device of the present disclosure has a simple structure and low cost. Further, the impeller may be designed to achieve a desired NVH level based on a specific fuel system. 
     The disclosure above encompasses multiple distinct inventions with independent utility. Which each of these inventions has been disclosed in a particular form, the specific embodiments disclosed and illustrated above are not to be considered in a limiting sense as numerous variations are possible. The subject matter of the inventions includes all novel and non-obvious combinations and subcombinations of the various elements, features, functions and/or properties disclosed above and inherent to those skilled in the art pertaining to such inventions. 
     The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application.