Patent Publication Number: US-8979514-B2

Title: Pump pressure control valve with shock reduction features

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/469,506 filed on Mar. 30, 2011. The entire disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a pump pressure control valve and, more particularly, to a pump pressure control valve with shock reduction features. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. Some modern internal combustion engines, such as engines fueled with gasoline, may employ direct fuel injection, which is controlled, in part, by a gasoline direct injection pump. While such gasoline direct injection pumps have been satisfactory for their intended purposes, a need for improvement exists. One such need for improvement may exist in the control of a pressure control valve. In operation, internal parts of a pressure control valve may come into contact with adjacent parts, which may cause noise that is audible to a human being standing a few feet (e.g. 3 feet or about 1 meter) away from an operating direct injection pump. Thus, improvements in method(s) of control to reduce audible noise of a gasoline direct injection pump are desirable. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     A pump having a stroke for moving a fluid is disclosed. The pump includes a pump casing defining a first chamber and a second chamber, and the fluid moves from the first chamber to the second chamber during the stroke. The pump also includes a needle that is movably disposed in the first chamber and a valve carriage that is movably disposed in the second chamber. The valve carriage includes an internal stop, and the valve carriage also includes a cavity therein that is partially defined by the internal stop. The pump further includes a valve that is movably disposed within the cavity of the valve carriage, and the valve is operable to be impacted by the needle during the stroke. Also, the needle is operable to impact the valve carriage during the stroke. Moreover, the valve is operable to impact the internal stop during the stroke at a time that is different from the needle impacting the valve carriage. 
     Additionally, a pump having a suction stroke for moving a fluid is disclosed. The pump includes a pump casing defining a first chamber and a second chamber, and the fluid moves from the first chamber to the second chamber during the suction stroke. The pump further includes a needle that is movably disposed in the first chamber and a valve carriage that is movably disposed in the second chamber. The valve carriage includes an internal stop, and the valve carriage also includes a cavity therein that is partially defined by the internal stop. A sleeve opening is defined in the valve carriage and provides access to the cavity. Furthermore, the pump includes a fluid passageway defined through the valve carriage, and the fluid passageway including a valve seat. The pump also includes a valve that is movably disposed within the cavity to seat on and unseat from the valve seat to control flow of the fluid into the cavity. The valve is operable to protrude partially from the sleeve opening. The needle is operable, during the suction stroke, to move toward the valve and the valve carriage and eventually impact the valve. Also, the needle is operable, during the suction stroke and after impacting the valve, to advance the valve into the cavity and unseat the valve from the valve seat. Furthermore, the needle is operable, during the suction stroke and after unseating the valve from the valve seat, to impact the valve carriage. Moreover, the valve is operable, during the suction stroke and after the needle impacts the valve carriage, to advance further into the cavity and impact the internal stop. 
     Still further, a vehicle fuel pump having a suction stroke and a pump stroke for moving a fuel is disclosed. The pump includes a pump casing defining a first chamber, a second chamber, a third chamber, and a fourth chamber. The pump also includes a needle that is movably disposed in the first chamber and that is biased toward the second chamber. Movement of the needle is selectively controlled by a solenoid. The pump also includes a valve carriage that is movably disposed in the second chamber. The valve carriage includes an internal stop, and the valve carriage also includes a cavity therein that is partially defined by the internal stop. A sleeve opening is defined within the valve carriage and provides access to the cavity. The pump also includes a first fluid passageway defined through the valve carriage, and the first fluid passageway includes a valve seat. A second fluid passageway is also defined through the internal stop. The pump also includes a valve that is movably disposed within the cavity and that is biased to seat against the valve seat and to protrude partially from the sleeve opening. The pump also includes a plunger that is movably disposed within the third chamber and a check valve that controls flow from the third chamber to the fourth chamber. The needle is operable, during the suction stroke, to move toward the valve and the valve carriage and eventually impact the valve. The needle is also operable, during the suction stroke, to advance the valve into the cavity and unseat the valve from the valve seat after impacting the valve. The needle is further operable, during the suction stroke, to impact the valve carriage after unseating the valve from the valve seat. The valve is operable, during the suction stroke, to advance further into the cavity and impact the internal stop after the needle impacts the valve carriage. The plunger is operable, during the suction stroke, to move within the third chamber to draw fuel along a flow path extending from the first chamber, through the first fluid passageway, through the cavity, through the second fluid passageway, and into the third chamber. Moreover, the check valve is operable, during the suction stroke, to prevent flow of fuel from the third chamber into the fourth chamber. The solenoid is operable, during the pump stroke, to energize to prevent impact of the needle against the valve such that the valve remains seated on the valve seat to prevent flow of fuel within the second chamber to the first chamber. Additionally, the plunger is operable, during the pump stroke, to move within the third chamber to open the check valve and pump the fluid within the third chamber into the fourth chamber. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
         FIG. 1  is a side view of a vehicle depicting a fuel system controlled by a method of operation in accordance with the present disclosure; 
         FIG. 2  is a side view of the vehicle fuel system of  FIG. 1 , depicting fuel injectors, a common rail, and a direct injection fuel pump controlled by a method of operation in accordance with the present disclosure; 
         FIG. 3  is a side view of the fuel system fuel pump module of  FIG. 2  in accordance with the present disclosure; 
         FIG. 4  is a cross-sectional view of a direct injection fuel pump in accordance with the present disclosure; 
         FIGS. 5-7  are cross-sectional views of a direct injection fuel pump depicting a plunger, a needle valve, a suction valve and associated pump structures in accordance with the present disclosure; 
         FIG. 8  is a graph depicting different strokes of the direct injection fuel pump relative to cam positions in accordance with the present disclosure; 
         FIGS. 9-11  depict various positions and contact locations of a needle, suction valve, and various physical stop structures of the direct injection fuel pump in accordance with the present disclosure; and 
         FIG. 12  depicts a cross-sectional view of an embodiment in accordance with the present disclosure. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Example structural embodiments and methods of control will now be described more fully with reference to  FIGS. 1-12  of the accompanying drawings. With reference first to  FIGS. 1-3 , a vehicle  10 , such as an automobile, is depicted having an engine  12 , a fuel supply line  14 , a fuel tank  16 , and a fuel pump module  18 . Fuel pump module  18  may mount within fuel tank  16  with a flange and may be submerged in or surrounded by varying amounts of liquid fuel within fuel tank  16  when fuel tank  16  possesses liquid fuel. An electric fuel pump  20  within fuel pump module  18  may pump fuel from fuel tank  16  to a direct injection fuel pump  22  through fuel supply line  14 . Upon reaching direct injection fuel pump  22 , liquid fuel may then be further pressurized before being directed into common rail  24  from which fuel injectors  26  receive fuel for ultimate combustion within combustion cylinders of engine  12 .  FIG. 3  depicts but one example of a fuel pump module that may be positioned within fuel tank  16 . More specifically, fuel pump module  18  may have a fuel pump module flange  28  may reside on a top surface of fuel tank  16  when fuel pump module  18  is in its installed position. 
     Continuing with  FIG. 3 , fuel pump module  18  includes a electric fuel pump  20  which may draw fuel from a reservoir  30  and then pump the fuel through a fuel pump check valve  32  and a fuel filter  34  surrounding electric fuel pump  20 . Fuel pump check valve  32  opens in response to fuel pressure from electric fuel pump  20  to permit fuel to flow from the top and out of electric fuel pump  20  and into filter  34 . In this manner, fuel pump check valve  32  permits fuel to be pumped from electric fuel pump  20  while preventing fuel from flowing in the opposite direction, that is, into the electric fuel pump  20 , when electric fuel pump  20  is not pumping, for example. Fuel pressure is maintained within and through the filter  34  disposed around the electric fuel pump  20 , but within a fuel filter case  36 . Fuel is pumped into filter  34  and forced through filter  34  toward the bottom of reservoir  30  where the fuel passes through a hole and into a pressure regulator  38 , which may be disposed within a pressure regulator case  40 . The pressure regulator case  40  may be attached to fuel filter case  36 , or integrally formed with fuel filter case  36 . Pressure regulator  38  is in fluid communication with the fuel supply line  14  via a feed line  42 . Pressure regulator  38  may regulate fuel pressure in feed line  42  and fuel supply line  14 . Fuel that passes from pressure regulator  38  flows into and through feed line  42  toward flange  28 . Flowing fuel, represented by arrow  44 , is fuel that is pumped from electric fuel pump  20 , through check valve  32  and to engine  12 . 
     Pressure regulator  38 , in addition to passing fuel into feed line  42  at the desired pressure in accordance with the reference setting pressure of pressure regulator  38 , re-circulates excess fuel, beyond that which is needed to maintain a reference pressure, back into reservoir  30  so that it again may be drawn into electric fuel pump  20 . Relatively low pressure fuel, or rather that pressure to which pressure regulator  38  is manufactured, is also routed from pressure regulator  38  to a jet pump  45 , which may be disposed near or at the bottom of fuel tank  16 , as depicted in  FIG. 3 . A fuel supply line check valve  46  may be calibrated to open in response to fuel pressure in feed line  42  when fuel pressure in feed line  42  is at or above a reference pressure to allow fuel to flow from pressure regulator  38 , through feed line  42 , and into the fuel supply line  14 . The pressure required to open the check valve  46  may vary with engine applications, for example. 
     With reference now including  FIG. 4 , structure and an associated method of controlling direct injection fuel pump  22 , by an engine controller or pump controller for example, will be presented. Direct injection fuel pump  22  may include an outer casing  48  (i.e., overall casing or pump casing) that generally defines an internal cavity  50  that defines other, smaller cavities and houses a variety of structures and parts that operate to pressurize and control fuel passing through direct injection fuel pump  22 . Specifically, the casing  48  can define a first chamber  54 , a second chamber  62 , a third chamber  72 , and a fourth chamber  84 , and the pump  22  can pump fuel (or other fluid) through the chambers  54 ,  62 ,  72 ,  84  in a manner to be discussed in detail. 
     Liquid fuel, such as gasoline, may flow through fuel supply line  14 , which may be connected to or ultimately lead to an inlet  52  of direct injection fuel pump  22 . Fuel flowing in accordance with arrow  44  may pass through inlet  52  and enter the first chamber  54 . A solenoid coil  56 , a needle  58 , and a needle spring  60  can be disposed within the first chamber  54 . The needle spring  60  can biases against an end of needle  58 , and the needle  58  can be movably disposed within the first chamber  54 . The spring  60  can bias the needle  58  toward the second chamber  62  as will be discussed. It will be appreciated that the needle  58  could be biased by another biasing member other than the spring  60  without departing from the scope of the present disclosure. 
     A suction valve carriage  92  can be movably disposed within the second chamber  62 , and a suction valve  64  can be movably disposed within an internal cavity  100  of the carriage  92 . The cavity  100  can be partially defined by an internal stop  138  as shown. The valve  64  can cooperate or work in conjunction with needle  58  and engage and disengage (i.e., seat and unseat) valve seat  66  to govern the flow of fuel through direct injection fuel pump  22 . Suction valve  64  may be biased with a spring  68  toward the first chamber  54  and toward the needle  58 . The spring  68  can bias against wall  70  of the internal stop  138  of the carriage  92 . It will be appreciated that the valve  64  could be biased by another biasing member other than the spring  68  without departing from the scope of the present disclosure. 
     Upon suction valve  64  becoming unseated from valve seat  66 , fuel can pass into the third chamber  72 , which may be a pressurization chamber  72 , where plunger  74 , whose outside diameter creates a seal yet permits sliding with internal diameter or surface  76 , pressurizes fuel to a desired pressure. Output pressure from pressurization chamber  72  is dependent upon the required output pressure of an internal combustion engine application. To assist in regulating output pressure, an outlet check valve  78  may seat and unseat from valve seat  80  in the fourth chamber  84  in accordance with a spring constant of spring  82 . To further facilitate pressurization of fuel in pressurization chamber  72 , an end  89  of plunger  74  can ride upon or contacts lobe(s) of a cam  86 , which may be directly or indirectly driven by rotation of engine  12 . Therefore, different plunger lengths and quantity of cam lobes may affect pressurization of fuel within chamber  72 . 
     Continuing with  FIG. 4 , needle  58  may contact and be guided by a needle guide  88 , which may have needle guide ends  90  that contact needle  58 . Moreover, needle guide may be annular and have an inside diameter that contacts needle  58 . 
     The suction valve carriage  92  can have an open end  94  (i.e. sleeve opening) through which an end of the valve  64  is exposed and through which the valve  64  can partially project. Suction valve carriage  92  may have one or more fluid inlet passages  96  (first fluid passages) and one or more fluid outlet passages  98  (second fluid passages) that allow flow of the fluid into and out of the cavity  100  of the carriage  92 . For instance, fluid inlet passages  96  may permit fluid passage from first chamber  54  to a suction valve internal cavity  100  while fluid outlet passages  98  may permit fluid passage from suction valve internal cavity  100  to a third chamber inlet  102  for passage of fluid into third chamber  72 . 
     Suction valve carriage  92  may be movable within second chamber  62  between a fixed stop or wall  109 , which separates first chamber  54  and second chamber  62 , and a suction valve carriage damper  108 . The damper  108  can be an annular-shaped spring or other device that dampens shock forces, vibrational loads, etc. Suction valve carriage damper  108  may reside between suction valve carriage  92  and a wall  106  that defines third chamber inlet  102 . As shown, suction valve carriage damper  108  may reside outside of suction valve carriage  92  and within second chamber  62 , while spring  68  may reside inside, or completely contained and surrounded by suction valve carriage  92  as an internal spring  68  of suction valve carriage  92 . 
     As mentioned above, third chamber  72  may be a pressurization chamber, and fourth chamber  84  may be an exit chamber for fluid exiting direct injection fuel pump  22 . Plunger  74  may move into and out of, and toward and away from, third chamber  72  to pressurize fluid in third chamber  72 . Outlet check valve  78  may work in conjunction with outlet check valve spring  82  to cover and uncover inlet  110  into fourth chamber  84 . Outlet check valve spring  82  may bias to permit fluid to enter fourth chamber  84  and subsequently from fourth chamber  84  via pump outlet  112  as exit fuel  114 . 
     Turning now to  FIGS. 5-7 , and with reference to  FIG. 8 , more specific control of direct injection fuel pump  22  will be described in accordance with the present disclosure. Operation of the pump  22  can be discussed in relation to a plurality of “strokes” of the pump  22 , exemplary embodiments of which are represented in  FIGS. 5-8 . 
     For instance, the pump  22  can have a suction stroke represented in  FIG. 5 , wherein fuel enters first chamber  54  in accordance with arrow  44 . With solenoid coil  56  de-energized, or turned off and with downward movement of plunger  74  (i.e. movement away from pressurization chamber  72 ), a suction force between inlet  52  through to pressurization chamber  72  is created due to a vacuum that forms and continues as plunger  74  moves away from pressurization chamber  72 . At the same time, check valve  78  may be seated against and form a seal with valve seat  80  as plunger  74  moves in accordance with arrow  117 , away from pressurization chamber  72 . Force of spring  82  facilitates seating of check valve  78  against seat  80  during a suction stroke of plunger  74  to draw fluid into pressurization chamber  72 . Vacuum created within pressurization chamber  72  also draws check valve toward seat  80 . Thus,  FIG. 5  depicts a scenario in which solenoid coil  56  is electrically de-energized so that fuel may be drawn into pressurization chamber  72  by plunger  74 . As depicted in  FIG. 8 , the position of plunger  74  of suction stroke of  FIG. 5  may coincide with decreasing or lessening cam lift, such as at position  118  of curve  116 . 
     When solenoid coil  56  is de-energized, needle spring  60  is able to force (bias) needle  58  away from solenoid coil  56  such that needle  58  contacts (abuts or impacts) the portion of the valve  64  projecting from the carriage  92 , thereby advancing the valve  64  further into the carriage  92  against the biasing force supplied by the spring  68 . After initially contacting the valve  64 , the needle  58  further moves toward and eventually impacts (contacts or abuts) an end surface  94  of the open end of suction valve carriage  92  and biases an opposite end of suction valve carriage  92  against suction valve carriage damper  108  thereby compressing suction valve carriage damper  108 . 
     As spring  68  compresses, suction valve  64  moves within suction valve carriage  92  and unseats from valve seat  66  to permit fuel to flow past suction valve  64  and into pressurization chamber  72 . Fuel flow (shown by arrows  44 ) is facilitated or hastened due to suction created by plunger  74  moving downward in accordance with arrow  116 . 
     With reference to  FIG. 6 , a pre-stroke, also known as a pre-pressurization stroke and a low pressure return stroke, is depicted and occurs when plunger  74  begins to move upward in accordance with arrow  117  within a cylinder or sleeve  120 . As depicted in  FIG. 6 , a pre-stroke phase constitutes a movement in which cam  86  ( FIG. 4 ) is in the process of lifting plunger  74 ; however, fuel is able to flow in reverse through direct injection fuel pump  22  in accordance with arrows  122  for a short period of time, and thus, fuel is not yet pressurized to an injection pressure in pressurization chamber  72 . Thus,  FIG. 6  represents a pumping scenario when solenoid coil  56  is off or de-energized, suction valve  64  is not seated against valve seat  66  and fuel is able to flow from pressurization chamber  72  through direct injection fuel pump  22  and out of casing inlet or pump inlet  52  as plunger  74  initially moves toward pressurization chamber  72 , such as just after a bottom dead center (“BDC”) position of plunger  74 . Exit check valve  78  may be seated against valve seat  80  during pre-stroke of  FIG. 6  as force of exit check valve spring  82  forces it against valve seat  80 . As depicted in  FIG. 8 , the position of plunger  74  of pre-stroke stroke of  FIG. 6  may coincide with increasing cam lift, such as at position  124  of curve  116 . 
       FIG. 7  depicts a pumping stroke in which plunger  74  moves further upward or toward pressurization chamber  72  in accordance with arrow  117 . As plunger  74  moves within sleeve  90 , fuel is pressurized within pressurization chamber  72 . As depicted in  FIG. 7 , a pumping stroke phase constitutes a movement in which cam  86  ( FIG. 4 ) is in the process of lifting or moving plunger  74  toward and to a position of top dead center (“TDC”) relative to lifting or movement capabilities of cam  86 . Fuel is able to flow through direct injection fuel pump  22  and exit pump  22  at pump outlet  128  in accordance with arrows  126  upon fuel being pressurized to a pressure that overcomes a spring force of check valve spring  82 . Thus, fuel is pressurized in pressurization chamber  72  and then exits through inlet to exit chamber  84 . 
     Thus,  FIG. 7  represents a scenario such that when solenoid coil  56  is on or energized, force of energized solenoid coil  56  attracts needle  58 , thereby compressing needle spring  60  and removing needle end  130  from contact with an end  132  of suction valve  64 . Thus, spring  68  then biases suction valve  64  against valve seat  66  to prevent fuel from flowing into first chamber or inlet chamber  54  and instead fuel is forced to flow into fourth chamber or exit chamber  84  and from outlet  128 . 
     Continuing with  FIG. 7 , when fuel is exiting from outlet  128 , the force of flowing fuel and/or associated pressure in chamber  72  may be greater than the resistant or compressive force of spring  82  against check valve  78  to permit compression of spring  82  and movement of check valve  78  such that fuel  126  is able to exit from outlet  112 . Spring  68  may bias against wall  70  when suction valve  64  is closing and bias suction valve  64  against valve seat  66  to prevent fuel from flowing through fluid inlet passages  96 . Similarly, spring  82  may bias against wall  134  when check valve  78  is moving check valve  78  away from valve seat  80  and to valve seat  80  (i.e. opening or closing, respectively). 
     Thus,  FIGS. 5-7  each represent a position of plunger  74 , a corresponding status (e.g. on or off) of solenoid coil  56  and an effect of plunger  74  position and solenoid coil  56  status on fuel flow through direct injection fuel pump  22 . As depicted in  FIG. 8 , the position of plunger  74  of pumping stroke of  FIG. 7  may coincide with increasing cam lift, such as at position  136  of curve  116 . 
       FIGS. 9-11  depict positions of internal components of direct injection fuel pump  22  during the different strokes or phases of operation.  FIG. 9  depicts positions of needle  58  and suction valve  64  during a pumping stroke when solenoid  56  is energized, as explained in conjunction with  FIG. 7 ; however, noise due to contact of needle  58  and suction valve  64  does not occur because suction valve  64  is seated against valve seat  80  and solenoid  56  is energized thus drawing needle  58  against spring holder  61 , which creates a gap between needle  58  and suction valve  64 . This occurs as plunger  74  travels toward a plunger TDC position ( FIG. 7 ). Because the valve  64  is seated on the valve seat  80 , no fluid flows through at least fluid inlet passages  96  during the pumping stroke  136 . 
       FIG. 10  depicts a beginning of a downward stroke of plunger  74  (e.g. suction stroke) in which electrical current to solenoid coil  56  is turned off, thus de-energizing solenoid coil  56  and preventing attraction of needle  58  against spring holder  61 . The needle  58  breaks physical contact with spring holder  61  and moves toward suction valve  64  due to the force of spring  60  biasing against spring holder  61 . Spring  60  may be fixed between or within solenoid coil  56 . Thus, spring  60  biases needle  58  to cause an end  130  of needle  58  to move into and strike an end  132  of suction valve  64 . As depicted in  FIG. 10 , when needle  58  strikes suction valve  64 , an audible noise may be created. Then, after needle  58  strikes suction valve  64 , needle  58  continues to travel toward suction valve carriage  92 , and when suction valve  64  moves past an end surface  94  of suction vale carriage  92  so that suction valve  64  is completely and entirely within confines of suction valve carriage  92 , the end surface  130  of needle  58  strikes the end surface  94  of suction valve carriage  92 . An audible noise may be created by such strike. Also, a shock load or vibration can be generated due to this impact. As shown in  FIG. 10 , the shock load or vibration (i.e., first load) can be transmitted through the carriage  92  to be dampened by the damper  108  as depicted by arrows  146 ,  148 . The damper  108  can act as a shock absorber to absorb the shock of impact between needle  58  with end surface  94  of suction valve carriage  92 . Damper  108  may be flexible and be a spring or perform as a spring to absorb energy from suction valve carriage  92 . 
       FIG. 11  depicts continuation of the suction stroke initiated in  FIG. 10  such that fluid may be drawn into fluid inlet passages  96 , into suction valve internal cavity  100 , into fluid outlet passages  98 , and subsequently into pressurization chamber  72 . Upon suction valve  64  moving from valve seat  66 , suction valve  64  may move toward and strike end surface  113  of internal stop  138  of suction valve carriage  92 . Internal stop  138  is part of suction valve carriage  92 . Internal stop  138  may define a receptacle for suction valve spring  68 . Internal stop  138  may include a cavity  142  defined by and surrounded by a wall  144 . Suction valve spring  68  may reside within cavity  142  such that only one end of suction valve spring  68  protrudes beyond an end surface  113  of wall  144 . When compressed by suction valve  64 , suction valve spring  68  may be compressed within cavity  142  and against wall  70  such that no portion of suction valve spring  68  protrudes beyond an end surface  140  of internal stop  138 . When suction valve  64  strikes end surface  113  of internal stop  138  which may lie completely within confines of suction valve carriage  92 , vibration and shock loads (i.e., second loads) created by the impact may be transmitted into and through suction valve carriage  92  in accordance with arrows  147  ( FIG. 11 ) and into damper  108 , which acts as a shock absorber and absorbs shock of impact between suction valve  64  and end surface  113  of internal stop  138  of suction valve carriage  92 . Because damper  108  may be flexible and may be a spring or perform as a spring to absorb energy from suction valve carriage  92 , vibration, shock and noise are absorbed or lessened than if damper  108  were to not exist and if suction valve carriage  92  were to directly strike dividing wall  106  that divides and lies between pressurization chamber  72  and exit chamber  84 . 
     A method of controlling the pump  22  may involve providing a first chamber  54  within a chamber casing  48 , which defines an inlet  52 . The method may also involve providing a first wall  109  that defines a first aperture  53  ( FIG. 4 ) to permit fluid to flow to suction valve carriage  92 . First chamber  54  may house a solenoid coil  56  and energization and de-energization of solenoid coil  56  can control movement of needle  58 . The method may also involve providing a second chamber  62  within chamber casing  48  with a suction valve  64 . The second chamber  62  may be located next to the first chamber  54  and first aperture  53  may define a fluid passageway between first chamber  54  and second chamber  62 . The method may further involve providing a third chamber  72  within chamber casing  48  that is open to a sleeve  120 , which may be cylindrical, containing a plunger  74 . The method may also involve providing a second wall  106  that defines a second aperture  102  as a fluid passageway between second chamber  62  and third chamber  72 . The method may also involve providing a fourth chamber  84  with exit valve  78  and a third wall  106  that defines a third aperture  110  between third chamber  72  and fourth chamber  84 . 
     Stated slightly differently, and in accordance with the present disclosure, pump  22  may employ needle  58 , suction valve  64 , and suction valve carriage  92  within which suction valve  64  may reside and move. In the following order during a suction stroke operation of pump  22 , needle  58  may contact suction valve  64 , and then needle  58  may contact suction valve carriage  92  (at contact point  117  of  FIG. 10 ) to transmit shock via arrows  146 ,  148  through suction valve carriage  92  and to suction valve carriage damper  108 . Subsequently, suction valve  64  may contact internal stop  138  of suction valve carriage  92  (at contact point  119  of  FIG. 11 ) to transmit shock via arrows  147  from surface  113  through internal stop  138  of suction valve carriage  92  and through a balance of suction valve carriage  92  to suction valve carriage damper  108 . 
     Pump  22  may further employ a pump casing  48 , which may be an outer casing, defining a first chamber  54  and a solenoid coil  56  residing within first chamber  54 . Pump casing  48  may define a second chamber  62 , and suction valve carriage  92  may reside within second chamber  62  against suction valve carriage damper  108 , and post, circular ring, holder, or wall  109 . Pump casing  48  may also define third chamber  72  and wall  106  may demarcate a division between second chamber  62  and third chamber  72 . Suction valve carriage damper  108  may reside between suction valve carriage  92  and wall  106  that demarcates the division between second chamber  62  and third chamber  72 . Suction valve carriage  92  may define first fluid passageway  96  that permits fluid from outside of the suction valve carriage to pass to a cavity  100  within the suction valve carriage  92 . (Fluid may also flow in a reverse direction depending upon a stroke of plunger  74 .) Suction valve carriage  92  may further define second fluid passageway  98  that permits fluid from cavity  100  within suction valve carriage  92  to pass outside of suction valve carriage  92 . Suction valve  64  may control passage of fluid from first fluid passageway  96  into cavity  100 . Suction valve carriage damper  108  may contact (e.g. flex in a spring-like or cantilever fashion) suction valve carriage  92  to dampen shock of needle  58  striking end surface  94  of suction valve carriage  92 , shock of needle  58  striking suction valve  64 . Suction valve spring  68  may reside within internal stop  138  of suction valve carriage  92  and may be compressible from beyond an end surface  94  of internal stop  138  of suction valve carriage  92  to be flush with end surface  94  of internal stop  138  of suction valve carriage  92 . Plunger  74  may reside within third chamber  72  defined by pump casing  48  and third chamber  72  may be fluidly linked to second chamber  62 . Outlet check valve  78  may be located in fourth chamber  84  defined by pump casing  48  and fourth chamber  84  may be fluidly linked to third chamber  72 . 
     Suction valve carriage  92  may define a sleeve  107  ( FIG. 4 ) into fluid reservoir  100  and suction valve  64  may partially reside within sleeve  107  and partially protrude beyond end surface  94  of suction valve carriage  92 . A width (e.g., diameter) of needle  58  may be greater than a width (e.g. inside diameter) of the opening of the sleeve  107  (i.e., the sleeve opening). Thus, suction valve carriage  92  may be a stop for needle  58  (i.e., limit movement of the needle  58  relative to the carriage  92 . Wall  106  may divide second chamber  62  and third chamber  72 , and suction valve carriage damper  108  may reside between suction valve carriage  92  and wall  106  that divides second chamber  62  and third chamber  72 . 
     In another arrangement, a pump  22  may employ first chamber  54  within chamber casing  48 , and a wall  106  may define a first aperture  102 . First chamber  54  may house solenoid coil  56 , which may control fore and aft movement of needle  58 . Pump  22  may employ second chamber  62  within chamber casing  48  with suction valve carriage  92  that contains movable suction valve  64 . A first wall  109  may define a first aperture  53  and may permit passage of fluid between first chamber  54  and second chamber  62 . Third chamber  72  may be defined within chamber casing  48  and may be open to a sleeve  107  containing plunger  74 . Second wall  106  may define a second aperture  102  as a fluid passageway between second chamber  62  and third chamber  72 . Fourth chamber  84  may house an exit valve  78  and third wall  111  may define third aperture  110  between third chamber  72  and fourth chamber  84 . During operation of pump  22  the following may take place in order: a) needle  58  and suction valve  64  may contact each other; b) needle  58  and suction valve carriage  92  may contact each other; and c) suction valve  64  may contact internal stop  138  of suction valve carriage  92 . 
     It is possible that the following contacts occur in the following order with reference to  FIGS. 9-11 : a) end surface  130  of needle  58  contacts end surface  132  of suction valve  64 ; b) end surface  130  of needle  58  contacts end surface  94  of suction valve carriage  92 ; and c) an end surface of suction valve  64  contacts end surface  113  of internal stop  138  of suction valve carriage  92 . 
     A vibration path through solid material is defined from suction valve carriage  92  into suction valve carriage damper  108  upon needle  58  contacting suction valve carriage  92 , and subsequently upon suction valve  64  contacting and end surface  113  of internal stop  138  of suction valve carriage  92 . Because two separate impacts occur, noise from pump  22  may be lower than if one object with a larger mass (e.g. a combination of needle  58  and suction valve  64  abut together and travel together as a single unit) impacts the end surface  113  of the internal stop  138 . 
       FIG. 12  depicts a cross-sectional view of an embodiment in accordance with the present disclosure. Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     An advantage of the present disclosure is that by constructing direct injection fuel pump  22  so that multiple strikes occur in succession between parts with relatively masses (such as when needle  58  strikes suction valve  64 , end surface  130  of needle  58  strikes end surface  94  of suction valve carriage  92 , and suction valve  64  strikes end surface  140  of internal stop  138  of suction valve carriage  92 ), instead of fewer strikes with larger masses, noise levels due to the impacts may be lessened, thereby making overall pump operation quieter. Additionally, teachings of the present disclosure may be successfully applied to an engine operating at any RPM. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.