Abstract:
A flow-through pressure regulator includes a retainer that secures a diaphragm relative to a seat, and includes a cylindrical portion, an axial end portion and an annular portion. The cylindrical portion extends about a longitudinal axis and is fixed with respect to the seat. The axial end portion extends from the cylindrical portion and extends generally orthogonal relative to the longitudinal axis. The axial end portion includes a plurality of apertures that permit fluid communication and are selected so as to reduce noise due to fluid flow.

Description:
CROSS REFERENCE TO CO-PENDING APPLICATIONS 
   This application claims the benefit of the earlier filing date of U.S. Provisional Application Ser. No. 60/386,535, filed Jun. 6, 2002, the disclosure of which is incorporated by reference herein in its entirety. 

   FIELD OF THE INVENTION 
   This invention relates to a pressure regulator for automotive fuel systems, and more particularly to a diaphragm-to-seat spring retainer that is perforated so as to reduce the noise associated with high fuel flow rates through the pressure regulator. 
   BACKGROUND OF THE INVENTION 
   Most modern automotive fuel systems utilize fuel injectors to deliver fuel to the engine cylinders for combustion. The fuel injectors are mounted on a fuel rail to which fuel is supplied by a pump. The pressure at which the fuel is supplied to the fuel rail must be metered to ensure the proper operation of the fuel injectors. Metering is carried out using pressure regulators that control the pressure of the fuel in the system at all engine r.p.m. levels. 
   Fuel flow rate, measured in liters per hour, through known pressure regulators tends to be low at high engine speed, measured in revolutions per minute, as large quantities of fuel are consumed in the combustion process. At low engine speeds, less fuel is consumed in combustion and flow rates through the pressure regulators are high. These high fuel flow rates can produce unacceptably high noise and pressure levels. 
   A first known pressure regulator, as shown in  FIG. 7 , includes a spring biased valve seat with a longitudinal flow passage. The longitudinal flow passage, which has a constant cross-section orthogonal to a longitudinal axis, can be modified for length along the longitudinal axis to slightly modify noise and flow performance characteristics. 
   A second known pressure regulator, as shown in  FIG. 8 , includes a necked-down longitudinal flow passage and mutually orthogonal cross-drilled holes. The cross-drilled holes disperse fluid flow in a manner that is effective to improve the noise and flow characteristics of the known regulator shown in  FIG. 7 . However, manufacturing a seat with the necked-down longitudinal flow passage and cross-drilled holes is costly to machine. 
   It is believed that there is a need for a pressure regulator that is less expensive to manufacture and maintains flow-related noise and pressure within acceptable levels, even at high fuel flow rates. 
   SUMMARY OF THE INVENTION 
   The present invention provides a flow-through pressure regulator. The flow-through pressure regulator includes a housing that has an inlet and an outlet that is spaced along a longitudinal axis from the inlet, a divider that separates the housing into a first chamber and a second chamber, and a closure member. The divider includes a seat, a diaphragm and a retainer. The seat defines a passage between the first and second chambers, and the diaphragm extends between the housing and the seat. Fluid communication between the first and second chambers is permitted through the passage, but is prevented through the diaphragm. The retainer secures the diaphragm relative to the seat, and includes a cylindrical portion, an axial end portion and an annular portion. The cylindrical portion extends about the longitudinal axis and is fixed with respect to the seat. The axial end portion extends from the cylindrical portion and extends generally orthogonal relative to the longitudinal axis. The axial end portion includes a plurality of apertures that permit fluid communication between the passage and the second chamber. The closure member may be arranged relative to the seat between a first configuration that substantially prevents fluid communication through the passage and a second configuration that permits fluid communication through the passage. 
   The present invention also provides a retainer for a flow-through pressure regulator. The flow-through pressure regulator includes a divider, a seat and a diaphragm. The divider separates a housing into a first chamber and a second chamber. The seat defines a passage between the first and second chambers. And the diaphragm extends between the housing and the seat. The retainer includes a cylindrical portion that extends about a longitudinal axis, an axial end portion that extends from the cylindrical portion, and an annular portion spaced along the longitudinal axis from the axial end portion. The axial end portion extends generally orthogonal relative to the longitudinal axis and includes a plurality of apertures. Fluid communication is permitted between the passage and the second chamber through the plurality of apertures. The annular portion extends from the cylindrical portion and outwardly relative to the longitudinal axis. 
   The present invention also provides a method of regulating fuel flow. The method includes flowing the fuel through a passage that extends along a longitudinal axis, collecting in a chamber the fuel flowed through the passage, and flowing through a plurality of apertures the fuel collected in the chamber. The passage has a first cross-section size orthogonal to the longitudinal axis. The chamber has a second cross-section size orthogonal to the longitudinal axis, and the second cross-section size is greater than the first cross-section size. Each of the plurality of apertures extends generally parallel to the longitudinal axis and has a third cross-section size that is orthogonal to the longitudinal axis. And the third cross-section size is less than the second cross-section size. 
   The present invention also provides a method of reducing noise in a flow-through pressure regulator. The flow-through pressure regulator includes a divider, a seat and a diaphragm. The divider separates a housing into a first chamber and a second chamber. The seat defines a passage between the first and second chambers. And the diaphragm extends between the housing and the seat. The method includes forming a diaphragm-to-seat retainer, and mounting the retainer with respect to the seat. The forming the retainer includes forming a cylindrical portion extending about a longitudinal axis, forming an axial end portion that extends from the cylindrical portion and extends generally orthogonal relative to the longitudinal axis, and perforating the axial end portion of the retainer so as to reduce noise due to fluid flow. The perforating includes selecting a plurality of apertures and selecting a pattern in which to arrange the plurality of apertures. The mounting the retainer provides a path for fluid flow that includes entering the first chamber, passing from the first chamber through the passage, passing through the plurality of apertures into the second chamber, and exiting the second chamber. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate presently preferred embodiments of the invention, and, together with the general description given above and the detailed description given below, serve to explain features of the invention. 
       FIG. 1  illustrates a flow-through regulator according to the present invention. 
       FIG. 2  illustrates a sectional view of the valve seat of the flow-through regulator shown in  FIG. 1 . 
       FIG. 3  illustrates a sectional view, taken along line III—III in  FIG. 4 , of the retainer of the flow-through regulator shown in  FIG. 1 . 
       FIG. 4  illustrates a detailed view of the retainer according to the present invention. 
       FIG. 5  is a graph illustrating the relationship between noise, measured in Sones, and flow rate, measured in kilograms per hour. 
       FIG. 6  is a graph illustrating the relationship between pressure, measured in kilopascals, and flow rate, measured in kilograms per hour. 
       FIG. 7  illustrates a first known pressure regulator. 
       FIG. 8  illustrates a second known pressure regulator. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  illustrates a flow-through pressure regulator  10  according to the present invention. The flow-through pressure regulator  10  includes a housing  20 . The housing  20  is separated by a divider  30  into a first chamber  40  and a second chamber  50 . The divider  30  has a passage  60  that communicates the first chamber  40  with the second chamber  50 . A closure member  70  permits or inhibits flow through the passage  60 . A filter  80  may be disposed in the flow path of the housing  20 . The housing  20  has an inlet  202  and an outlet  204  offset along a longitudinal axis A. The housing  20  can include a first housing part  206  and a second housing part  208  that are crimped together to form a unitary housing  20  with a hollow interior  211 . Although the unitary housing is formed by two joined members, it is to be understood that the unitary housing could be formed with multiple members integrated together or, alternatively, a monolithic member. The inlet  202  of the housing  20  is located in the first housing part  206 , and the outlet  204  of the housing  20  is located in the second housing part  208 . The inlet  202  can be a plurality of apertures  210  located in the first housing part  206 . The outlet  204  can be a port  212  disposed in the second housing part  208 . 
   The first housing part  206  can include a first base  214 , a first lateral wall  218  extending in a first direction along the longitudinal axis A from the first base  214 , and a first flange  220  extending from the first lateral wall  218  in a direction substantially transverse to the longitudinal axis A. The second housing part  208  can include a second base  222 , a second lateral wall  224  extending in a second direction along the longitudinal axis A from the second base  222 , and a second flange  226  extending from the second lateral wall  224  in a direction substantially transverse to the longitudinal axis A. A divider  30 , which can include a diaphragm  300 , is secured between the first flange  220  and the second flange  226  to separate the first chamber  40  and the second chamber  50 . The first flange  220  can be rolled over the circumferential edge of the second flange  226  and can be crimped to the second flange  226  to form the unitary housing  20 . 
   A first biasing element  90 , which is preferably a spring, is located in the second chamber  50 . The first biasing element  90  engages a locator  228  on the base  222  of the second housing part  208  and biases the divider  30  toward the base  214  of the first housing part  206 . The first biasing element  90  biases the divider  30  of the regulator  10  at a predetermined force, which relates to the pressure desired for the regulator  10 . The base  222  of the second housing part  208  has a dimpled center portion that provides the outlet port  212  in addition to the locator  228 . The first end of the spring  90  is secured on the locator  228 , while a second end of the spring  90  can be supported by a retainer  302 , which is secured to a valve seat  304  mounted in a central aperture  306  in the diaphragm  300 . 
     FIG. 2  shows a preferred embodiment of the valve seat  304 . The valve seat  304  is suspended by the diaphragm  300  in the housing  20  ( FIG. 1 ), and provides the passage  60  that includes a first section  602  and a second section  604 . The valve seat  304  has a first seat portion  304 A and a second seat portion  304 B disposed along the longitudinal axis A. The first seat portion  304 A is disposed in the first chamber  40  and the second seat portion  304 B is disposed in the second chamber  50  ( FIG. 1 ). The first section  602  of the passage  60  extends along the longitudinal axis A in both the first portion  304 A and the second portion  304 B of the valve seat  304 . The second section  604 , which also extends along the longitudinal axis A, is in the second portion  304 B of the valve seat  304 . 
   The valve seat  304  preferably has a first surface  308  disposed in the first chamber  40  ( FIG. 1 ), a second surface  310  disposed in the second chamber  50  ( FIG. 1 ), and a side surface  312  extending between the first surface  308  and the second surface  310 . The first section  602  of the passage  60  communicates with the first surface  308 . The second section  604  of the passage  60  communicates with the first section  602  and the second surface  310 . The first section  602  has a first diameter  606 A and the second section  604  has a second diameter  606 B that is necked-down from the first diameter  606 A, as shown in  FIG. 2 . 
   The side surface  312  of the valve seat  304  may include an undercut edge  314  that may enhance the press-fitted connection between the retainer  302  and the valve seat  304 . 
   It should be noted that the valve seat  304  of the present invention can be manufactured as a monolithic valve seat or, alternatively, as separate components that can be assembled. The dimensions illustrated in  FIG. 2  are merely exemplary of one preferred embodiment of the valve seat  304 . 
   At an end of the passage  60  opposite the second seat surface  310  is a seating surface  62  for seating the closure member  70 , which can be a valve actuator ball  64 , as shown in phantom line in  FIG. 2 . In the manufacturing of the valve seat  304 , the seating surface  62  is finished to assure a smooth sealing surface for the ball  64 . 
     FIGS. 3 and 4  show a preferred embodiment of the retainer  302 . The retainer  302  includes a cylindrical portion  320  that extends about the longitudinal axis A. According to a preferred embodiment, an inner surface of the cylindrical portion  320  is press-fitted with respect to the side surface  312  of the seat  304 , and may cooperatively engage the undercut edge  314 . 
   The retainer  302  also includes an axial end portion  322  that extends from the cylindrical portion  320  generally orthogonally relative to the longitudinal axis A. The axial end portion  322  includes a plurality of apertures  324 , 326  through which fluid communication between the passage  60  and the second chamber  50  is permitted. 
   Referring additionally to  FIG. 4 , and according to a merely exemplary preferred embodiment with seven apertures, a first aperture  324  is located concentrically with respect to the longitudinal axis A. The six remaining apertures  326  are formed in a circular pattern  328  centered about the longitudinal axis A. According to a most preferred embodiment, each of the apertures  324 , 326  has a diameter of 1.59±0.02 millimeters, the circle pattern  328  has a diameter of approximately 5.5 millimeters, and six apertures  326  are evenly spaced, i.e., every 60°, about the longitudinal axis A. Additionally, a preferred ratio of the longitudinal thickness of the axial end portion  322  to the diameter of the apertures  324 , 326  is approximately 0.35. 
   The inventors have discovered that the noise and flow characteristics through the pressure regulator  10  are responsive to the number/shape/size of apertures  324 , 326 , the pattern of the apertures  324 , 326  on the axial end portion  322 , and the thickness of the axial end portion  322  that is penetrated by the apertures  324 , 326 . Additionally, the inventors have discovered that providing a collection chamber  330  in the fluid flow between the passage  60  and the apertures  324 , 326  also improves the noise and flow characteristics through the pressure regulator  10 . 
   Referring again to  FIG. 3 , the retainer  302  also includes an annular portion  332  that extends from the cylindrical portion  320  in a generally radially outward direction relative to the longitudinal axis A. The annular portion  332  is spaced along the longitudinal axis A from the axial end portion  322  and, in cooperation with the first seat portion  304 A, sandwiches the diaphragm  300 , thereby coupling the diaphragm  300  to the valve seat  304 . The retainer  302  also serves to support and to locate the second end of the spring  90  with respect to the divider  30 . 
   The dimensions illustrated in  FIGS. 3 and 4  are merely exemplary of one preferred embodiment of the retainer  302 . 
   One method of assembling the fuel regulator  10  is by coupling, such as by staking or press-fitting, the closure member  70  to the first housing part  206 . The divider  30  is assembled by locating the valve seat  304  in the central aperture  306  of the diaphragm  300 , and then press-fitting the spring retainer  302  with respect to the seat  304  such that the side surface  312  contiguously engages the cylindrical portion  320 . The assembled divider  30  is located with respect to the upper flange surface  220  of the first housing part  206 . The bias spring  90  is positioned in the spring retainer  302  and the second housing part  208  is then placed over the spring  90 . The flange  220  of the first housing part  206  is crimped down to secure the second housing part  208 . The first and second housing parts  206 , 208  and the diaphragm  300  form the first and second chambers  40 , 50 , respectively. The pressure at which the fuel is maintained is determined by the spring force of the bias spring  90 . 
   The operation of the flow-through pressure regulator will now be described. The bias spring  90  acts through the retainer  302  to bias the divider  30  toward the base  214  of the first housing part  206 . When the ball  64  is seated against surface  62 , the pressure regulator  10  is in a closed configuration and no fuel can pass through the pressure regulator  10 . 
   Fuel enters the pressure regulator  10  through apertures  210  and exerts pressure on the divider  30 . When the pressure of the fuel is greater than the force exerted by the bias spring  90 , the diaphragm  300  moves in an axial direction and the ball  64  leaves the seating surface  62  of the valve seat member  304 . This is the open configuration of the pressure regulator  10 . Fuel can then flow through the regulator  10 . From the first chamber  40 , the fuel enters the first section  602  of the passage  60 , and then passes into the second section  604  before entering the collection chamber  330 . From the collection chamber  330 , the fuel passes through the apertures  324 , 326  into the second chamber  50  before leaving the pressure regulator through the outlet  204 . 
   As the incoming fuel pressure is reduced, the force of the bias spring  90  overcomes the fuel pressure and returns the valve seat member  304  to seated engagement with the ball  64 , thus closing the passage  60  and returning the pressure regulator to the closed configuration. 
   Experimentation has shown that by designing the apertures  234 , 236  and/or the collection chamber  330  according to the present invention, a substantially constant noise output level can be achieved from a low fuel flow rate to a high fuel flow rate. Further, the pressure of fuel in the regulator  10  has been found to remain substantially constant or decrease slightly as the fuel flow rate increases from a low fuel flow rate to a high fuel flow rate. 
   As shown in  FIG. 5 , curves A 3 –A 7  and A 9 –A 11  show that flow-related noise is kept generally consistent over a range of fuel flow rates using the regulator  10  of the present invention. The performance of the regulator  10  is generally consistent with the performance, as illustrated by curves A 1 , A 2  and A 8 , of known pressure regulators that do not have the advantages of pressure regulator  10 , e.g., ease of manufacture and reduction in cost. 
   As shown in  FIG. 6 , curves B 4 –B 13  show that fuel pressure in the regulator  10  at the maximum fuel flow rate is substantially equal to or less than the fuel pressure at the minimum fuel flow rate. Again, the performance of the regulator  10  is generally consistent with the performance, as illustrated by curves B 1 –B 3 , of known pressure regulators that do not have the advantages of pressure regulator  10 . 
   While the invention has been disclosed with reference to certain preferred embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the invention, as defined in the appended claims and their equivalents thereof. Accordingly, it is intended that the invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims.