Abstract:
A pressure regulator includes a housing at least partially defining a chamber. A tube defines a valve seat having an inlet disposed inside the chamber, an outlet, and a passageway extending from the inlet to the outlet. The passageway is characterized by a first portion and a second portion that is narrower than the first portion. A valve member is selectively movable between a closed position in which the valve member obstructs the inlet and an open position in which the valve member does not obstruct the inlet. A spring biases the valve member toward the closed position.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to pressure regulators in vehicle fuel systems. 
       BACKGROUND 
       [0002]    Vehicles typically use a fuel pump to pressurize fuel in a tank for delivery to one or more fuel injectors in an engine via a fuel line. In some vehicles, the pump maintains a constant pressure regardless of the fuel consumption of the engine. A pressure regulator is employed to return fuel from the pump or the fuel line to the tank when the pressure exceeds a predetermined amount. 
       SUMMARY 
       [0003]    A pressure regulator includes a housing at least partially defining a chamber. A tube defines a valve seat having an inlet disposed inside the chamber, an outlet, and a passageway extending from the inlet to the outlet. The passageway is characterized by a first portion and a second portion that is narrower than the first portion. A valve member is selectively movable between a closed position in which the valve member obstructs the inlet and an open position in which the valve member does not obstruct the inlet. A spring biases the valve member toward the closed position. 
         [0004]    The second, narrower portion of the passageway adds back pressure to the regulator when fuel flows therethrough, which forces the valve member to open further, i.e., move further from the inlet, thereby reducing potential noise generated by fuel flow through the inlet. Since the tube is a separate piece from the housing, the benefit of the narrowed portion of the passageway may be added to existing regulator designs without extensive tooling or design changes. 
         [0005]    The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a schematic view of an engine system including an engine, a tank for storing fuel, a pump for transmitting fuel from the tank to the engine, and a pressure regulator for the pump; and 
           [0007]      FIG. 2  is a schematic, cross-sectional view of the pressure regulator of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0008]    Referring to  FIG. 1 , an internal combustion reciprocating engine  10  includes an engine block  14 , which defines a plurality of cylinders (not shown), as understood by those skilled in the art. The engine  10  also includes one or more fuel injectors  18  that are configured to inject fuel into the engine&#39;s intake system for subequent combustion inside the cylinders. The injectors  18  are operatively connected to a fuel rail  20  to receive fuel therefrom. The fuel rail  20  is in fluid communication with the chamber  22  of a fuel tank  26  to receive fuel therefrom. 
         [0009]    More specifically, the tank  26  is configured to store fuel within the chamber  22  for use in the engine  10 . A fuel pump  30  is configured to pressurize fuel from the fuel tank chamber  22  for transmission to the injectors  18 . More specifically, the fuel pump  30  pressurizes fuel from the fuel tank chamber  22  and transmits the pressurized fuel via a conduit  34  to a fuel filter  38 . The fuel filter  38  is in fluid communication with the injectors  18  via a fuel line  42  that interconnects the filter  38  and the injectors  18 . A fuel pressure regulator  46  is operatively connected to the filter  38 . 
         [0010]    The regulator  46  is in fluid communication with the pump  30  and the fuel line  42  via the filter  38  and a conduit  50 . The regulator  46  is configured to prevent the pressure in the fuel line  42  from exceeding a predetermined amount. Referring to  FIG. 2 , wherein like reference numbers refer to like components from  FIG. 1 , the regulator  46  includes a housing  54 . The housing includes a first housing member  58  and a second housing member  62  that are operatively connected to each other, such as by crimping, as shown. More specifically, in the embodiment depicted, a flange of the second housing member  62  is crimped over a flange of the first housing member  58  as shown. An elastic diaphragm  64  is engaged with the crimped joint between the first and second housing members  58 ,  62 . 
         [0011]    The first housing member  58  includes a cylindrical wall  66  and an end wall  70 . The cylindrical wall  66 , the end wall  70 , and the diaphragm  64  cooperate to define a generally cylindrical first chamber  74 . The end wall  70  is characterized by a protuberance  78  that extends into the first chamber  74 . The second housing member  62  includes a generally cylindrical wall  82  and an end wall  86 . The cylindrical wall  82 , the end wall  86 , and the diaphragm  64  cooperate to define a generally cylindrical second chamber  90 . Thus, the first and second chambers  74 ,  90  are separated by the diaphragm  64 . 
         [0012]    The regulator  46  in the embodiment depicted includes a base member  94  and a seal  98 . The seal  98  is annular and surrounds the generally cylindrical wall  82  opposite the second chamber  90 . Conduit  50  engages the seal  98  to provide fluid communication between the regulator assembly  46  and the fluid passageway  110  of the conduit  50 . The base member  94  defines at least one hole  102 . The end wall  86  defines a plurality of holes  106  offset from the central axis of the regulator  46 . Holes  102  and  106  are sufficiently aligned such that the passageway  110  of the conduit  50  is in fluid communication with the second chamber  90  via the holes  102 ,  106 , and thus the pump  30  and the fuel line  42  are in fluid communication with the chamber  90 . 
         [0013]    The end wall  86  also defines a hole  114  at the axis of the regulator  46 , and the base member  94  defines a hole  118  that is aligned with hole  114 . An outlet tube  122  extends through the holes  114 ,  118  such that part of the tube  122  is inside the second chamber  90  and part of the tube  122  is outside the chamber  90 . The outlet tube  122  defines a passageway  126  that extends through the tube  122  from an inlet  138  to an outlet  142 . The passageway  126  is characterized by a wide first portion  130  and a narrow second portion  134 . The wide portion  130  extends from the inlet  138  to a lip or step  144  that extends radially inward. The narrow portion  134 , which has a smaller cross-sectional diameter than the wide portion  130 , extends from the lip or step  144  to the outlet  142 . In the embodiment depicted, the lip or step provides an immediate transition from the wide portion to the narrow portion, i.e., there is not a tapered segment between the wide portion and the narrow portion. The tube  122  in the embodiment depicted is of one-piece construction. 
         [0014]    The outer surface of the tube  122  defines an annular groove  146 . An annular seal  150  is disposed within the groove  146 . Conduit  154  defines a passageway  158  that provides fluid communication between the outlet  142  of the passageway  126  and a reservoir or the fuel tank chamber (shown at  22  in  FIG. 1 ). The conduit  154  is engaged with the seal  150  to retain the conduit  154  with respect to the tube  122 . The inlet  138  is inside the second chamber  90 , and thus the tube  122  provides fluid communication between the second chamber  90  and the passageway  158  and, correspondingly, the reservoir or tank chamber  22 . 
         [0015]    A valve member  162  is disposed within the second chamber  90  and is configured to selectively obstruct the inlet  138  thereby to prevent fluid communication between the second chamber  90  and the passageways  126 ,  158 . More specifically, when the valve member  162  is in a closed position, as shown in  FIG. 2 , the valve member engages the end of the tube  122 , thereby obstructing fluid flow from the second chamber  90  to the passageways  126 ,  158 . Accordingly, the portion of the tube  122  inside the chamber  90  functions as a valve seat. The valve member  162  is moveable along the axis toward the diaphragm  64  to an open position (not shown) in which the inlet  138  is unobstructed, thereby permitting fluid flow from the second chamber  90  to the passageway  126 . 
         [0016]    A spring  166  is configured to bias the valve member  162  in the closed position. More specifically, in the embodiment depicted, the spring  166  is disposed within the first chamber  74 . One end of the spring  166  abuts end wall  70 . The other end of the spring  166  abuts a plate  170 . The plate  170  is operatively connected to a valve support member  174 . More specifically, the plate  170  defines a hole  178  and the diaphraphm  64  defines a hole  182 . Holes  178 ,  182  align along the axis of the regulator  46 . The valve support member  174  extends through holes  178 ,  182 . The valve support member  174  defines a cavity  186  in which a spring  190  is disposed. A plate  194  extends across the opening of the cavity  186  and retains the valve member  162  with respect to the valve support member  174 . A spherical portion  198  of the valve member  162  extends through the plate  194  and into the cavity  186 , where the spring  190  contacts the spherical portion  198 . 
         [0017]    During operation of the regulator  46 , fuel from the filter  38  enters the second chamber  90  via the passageway  110  of conduit  50  and holes  102 ,  106 . The fuel in the second chamber  90  exerts pressure on the diaphram  64 . The diaphragm transfers the force of the fuel to the spring  166 . That is, the diaphragm  64  is positioned and configured to transmit pressure from the second chamber  90  to the spring  166  to act against the spring bias. The spring  166  maintains the valve member  162  in the closed position until the pressure of the fuel inside the second chamber  90  is sufficiently high to overcome the bias of the spring  166 , and the valve member  162  moves to the open position, thereby allowing fuel in the chamber  90  to exit through the inlet  138 , passageway  126 , outlet  142 , and passageway  158 . 
         [0018]    The narrow portion  134  of the passageway  126  of tube  122  adds back pressure to the regulator  46 , forcing the valve member  162  to open wider, thereby reducing noise generated by the fuel flow through the inlet  138 . More specifically, the narrow portion  134  of the passageway  126  adds back pressure to the regulator  46 , which causes the valve member  162  to move further from the inlet  138  along the axis of the regulator compared to the amount that the valve member  162  would move if the entire length of the passageway  126  had the cross-sectional area of the wide portion  130 . In one embodiment, the wide portion  130  has a diameter of 3.0 millimeters, and the narrow portion  134  has a diameter of 2.2 millimeters. 
         [0019]    While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.