Patent Document

FIELD OF THE INVENTION 
     This invention relates to a fuel system for an internal combustion engine, and more particularly to a fuel system including a flow-through pressure regulator with a self-contained valve assembly for a vehicle powered by a fuel injected combustion engine. 
     BACKGROUND OF THE INVENTION 
     Most modern automotive vehicles are powered by an internal combustion engine that is connected with a source of fuel, e.g., gasoline, diesel, natural gas, alcohol, hydrogen, etc. The fuel is stored on-board the vehicle and supplied to the engine in a precisely controlled manner. 
     According to a conventional fuel system, gasoline is stored in a tank on-board a vehicle. The gasoline is withdrawn from the tank by a pump and fed through a filter to fuel injectors, which deliver the gasoline to combustion cylinders in the engine. The fuel injectors are mounted on a fuel rail to which fuel is supplied by the 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 by using pressure regulators which control the pressure of the fuel in the system at all engine r.p.m. levels. 
     It is believed that some existing pressure regulators employ a spring biased valve seat with a longitudinal flow passage. The valve seat is biased to a closed position at low fuel pressures. As fuel pressure builds in the system, the pressure against the valve seat overcomes the biasing force of the spring, allowing fuel to flow through the valve seat, thereby controlling the fuel pressure in the system. 
     In this type of pressure regulator, the valve seat and valve member were distinct components with various parts. The components are located at different positions within the housing of the pressure regulator and provide a valve assembly with distributed operative parts. These parts are believed to require detailed machining to fabricate. Thus, it is believed that a flow-through pressure regulator is needed that has a valve assembly that can be fabricated with fewer machined components, as well as with fewer components overall and that is configured within the pressure regulator so that the components are contained with a single operative part, i.e., self-contained. 
     SUMMARY OF THE INVENTION 
     The present invention provides a fuel system for an internal combustion engine powered by fuel that includes a fuel tank having a wall defining a volume. The fuel system also includes a pump that is disposed proximate the fuel tank and operatively connected to the volume. The fuel system further includes piping that is coupled to the pump and is operatively coupled to the internal combustion engine. A pressure regulator with a self-contained valve assembly is disposed in at least one of the pump or the piping. 
     The present invention also provides a method of supplying fuel tank to an internal combustion engine using a pump, a pressure regulator, and piping connecting the fuel tank, internal combustion engine, pump, and pressure regulator. The pressure regulator includes a self-contained valve assembly and an inlet and an outlet offset along an axis. The method is achieved by disposing the valve assembly with a closure member in a fluid flow path between the inlet and the outlet. The valve assembly defines the communication path between the inlet and the outlet. The method is also achieved by occluding flow between the inlet and outlet through the communication path of the valve assembly with the closure member when the valve assembly is in a first position at a first pressure and by permitting flow between the inlet and outlet through the communication path of the valve assembly when the valve assembly is in a second position at a second pressure. 
    
    
     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 the features of the invention. 
     FIG. 1 illustrates a fuel system according to the present invention. 
     FIG. 2 illustrates a flow-through regulator according to a preferred embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 illustrates a fuel system  1000  including a tank  1010 , a pump  1020 , a filter  1030 , a pressure regulator  1040 , a fuel rail  1050 , at least one fuel injector  1060 , and an internal combustion engine  1070 . These components are interconnected by piping as will be described in greater detail below. 
     The tank  1010  holds fuel. The pump  1020  is shown connected to an inside of the fuel tank  1010 . In other words, the pump  1020  can be secured to or retained to or supported by the inside of the fuel tank  1010 . However, the pump  1020  can also be connected on an exterior of the tank  1010 , or can be remotely connected with respect to the tank  1010 . The filter  1030  and the pressure regulator  1040  are shown connected inside the pump  1020 . However, the filter  1030  and the pressure regulator  1040 , either individually or an integral combination, can also be connected on the exterior of the pump  1020 , or can be connected remotely with respect to the pump  1020 . The tank  1010 , pump  1020 , filter  1030 , and pressure regulator  1040  can be coupled by piping such that the fuel  1012  can be filtered in the filter  1030  before entering the pump  1020 , or between the pump  1020  and the fuel rail  1050 . Coupling thus refers to any connection permitting fluid communication. The pressure regulator  1040  can be coupled to a tap in piping between the pump  1020  and the filter  1030 , or between the filter  1030  and the fuel rail  1050 . Fuel  1012  that is bled-off by the pressure regulator  1040  is returned to the pump  1020 . The fuel  1012  supplied to the fuel rail  1050  is supplied to each of the injector(s)  1060 , and subsequently supplied by the injector  1060  to the engine  1070 , e.g., into individual combustion cylinders of the engine  1070 . 
     FIG. 2 illustrates a flow-through pressure regulator  10  according to a preferred embodiment. The flow-through pressure regulator  10  includes a housing  20 . The housing  20  is separated by a valve assembly  30  into a first chamber  40  and a second chamber  50 . The valve assembly  30  has a passage  60  that communicates the first chamber  40  with the second chamber  50 . The valve assembly  30  permits or inhibits flow through the passage  60 . A filter  80  is 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 cup-shaped member  206  and a second cup-shaped member  208  that are crimped together to form a unitary housing  20  with a hollow interior  211 . Although the unitary housing  20  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. Furthermore, while the preferred embodiment of the housing  20  includes cup-shaped members, the housing  20  can include other geometries as well, such as tubular-shaped members. The inlet  202  of the housing  20  is located in the first cup-shaped member  206 , and the outlet  204  of the housing  20  is located in the second cup-shaped member  208 . The inlet  202  can be a plurality of inlet apertures  210  located in the first cup-shaped member  206 . The outlet  204  can be a port  212  disposed in the second cup-shaped member  208 . 
     The first cup-shaped member  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 cup-shaped member  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. The valve assembly  30  includes a flexible divider  300 , which can be a diaphragm. The divider  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 . 
     In addition to the divider  300 , the valve assembly  30  includes a tubular member  320  and a closure member  340 . The tubular member  320  is located in a central aperture  306  of the divider  300  to provide the passage  60 . The tubular member  320  includes a first tubular portion  322  and a second tubular portion  324 . The first tubular portion  322  is disposed entirely within the first chamber  40  and has a diameter disposed along the axis. An upper surface of the first tubular portion  322  extends substantially transverse to the longitudinal axis A and contacts a lower operative surface of the divider  300 . The first tubular portion  322  forms a chamber  326  housing the closure member  340 . The second tubular portion  324  is disposed substantially within the second chamber  50  and has a diameter disposed along the axis. The diameter of the second tubular portion  324  is smaller than the diameter of the first tubular portion  322 . An outer surface of the second tubular portion  324  is secured to a spring retainer  302 , preferably by an interference fit. The outer surface of the second tubular portion  324 , however, may be secured to the spring retainer  302  by staking or crimping. A lower end of the second tubular portion  324  extends beyond the divider  300  into the first chamber  40  and forms a unitary tubular junction  348  with an upper end of the first tubular portion  322 . The second tubular portion  324  includes a plurality of tubular apertures  325  located in an end proximate the outlet  204  to provide a flow path through the passage  60 . 
     The closure member  340  includes a ball  342  retained in a ball retainer  344 . The ball retainer  344  is disposed in the chamber  326  housing the closure member  340  and can be a flat annulus secured within chamber  326  by a flange provided at the lower end of the first tubular portion  322 . The flange of the lower end of the first tubular portion  322  allows for the ball retainer to move within the chamber  326 . This can be achieved by providing an aperture in the ball retainer  344  with an outside diameter which is smaller than an inner diameter of the first tubular portion  322 . The difference in diameters allows the ball retainer to move freely both axially and radially within the chamber  326 . The ball retainer  344  has a central aperture and a plurality of retainer apertures  346  located along a circumference of the ball retainer  344 . The central aperture of the ball retainer  344  is somewhat smaller than the diameter of the ball  342  and is finished to prevent a rough surface from contacting the ball  342 . The plurality of retainer apertures  346  in the ball retainer  344  permit flow through the first tubular portion  322 . An upper surface of the ball  342  seats on the tubular junction  348 . A lower surface of the ball  342  seats on a seating surface  230  formed in a center portion of the first base  214  along the longitudinal axis A and opposite the tubular junction  348 . 
     A first biasing element  330 , which can be a spring, is disposed within an inner diameter of the second tubular portion  324 , substantially within the second chamber  50 . An outer surface of the first biasing element  330  contacts an inner diameter of the second tubular portion  324 . The first biasing element  330  extends along the length of the second tubular portion  324 . An upper end of the first biasing element  330  engages the end of the second tubular portion  324  proximate the outlet  204 , while a lower end of the first biasing element  330  contacts the upper surface of the ball  342 . The first biasing element  330  biases the ball  342  at a predetermined force toward the base  214 . 
     A second biasing element  90 , which can be a spring, is disposed entirely within the second chamber  50  and is concentric with the first biasing element  330 . The second biasing element  90  engages a locator  228  on the base  222  of the second cup-shaped member  208  and biases the valve assembly  30  toward the base  214  of the first cup-shaped member  206 . The second biasing element  90  biases the valve assembly  30  at a predetermined force, which relates to the pressure desired for the regulator  10 . The base  222  of the second cup-shaped member  208  has a dimpled center portion that provides the outlet portion  212  in addition to the locator  228 . A first end of the second biasing element  90  is secured on the locator  228 , while a second end of the second biasing element  90  can be supported by the spring retainer  302 . 
     The operation of the flow-through pressure regulator  10  will now be described. It is to be understood that the following description can also explain the operation of the invention when utilized as a pressure-relief device. The second biasing element  90  acts through the spring retainer  302  to bias the divider  300 , and hence the valve assembly  70 , toward the base  214  of the first cup-shaped member  206 . The first biasing element  330  biases the ball  342  of the closure member  340 , against the seating surface  230  in the base  214  of the first cup-shaped member  206 . When the ball  342  is seated against the tubular junction  348 , the valve assembly  70  is in a closed position, and no fuel can pass through the regulator  10 . 
     Fuel enters the regulator  10  through inlet apertures  210  and exerts pressure on the valve assembly  70 , including the divider  300 . When the pressure of the fuel is greater than the force exerted by the second biasing element  90 , the valve assembly  70  is displaced along the longitudinal axis A toward the outlet  204 . The force exerted by the first biasing element  330  unseats the ball  342  from the tubular junction  348  creating a pathway for the fuel. Fuel enters the first tubular portion  322  around the ball  342  and through the plurality of retainer apertures  346  located in the ball retainer  344 . The fuel enters the passage  60  through the gap created by the unseated ball  342  and exits the passage  60  along and transverse to the longitudinal axis A through the plurality of tubular apertures  325  located in the end of the second tubular portion  324  proximate the outlet  204 . 
     As the fuel pressure is reduced, the force of the second biasing element  90  overcomes the fuel pressure and returns the tubular junction  348  to seated engagement with the ball  342 , thus closing the passage  60 . Operating in this manner, the regulator  10  is able to maintain constant fuel pressure in a fuel system. 
     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.

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