Patent Publication Number: US-6981491-B2

Title: Coupling valve structure for fuel supply module

Description:
This Application is based on U.S. Provisional Application No. 60/540,541, filed on Jan. 30, 2004, and claims the benefit thereof for priority purposes. 

   FIELD OF THE INVENTION 
   This invention relates to fuel supply module for vehicles and, more particularly, to a coupling valve structure that incorporates a check valve and pressure relief valve. 
   BACKGROUND OF THE INVENTION 
   Conventional fuel supply modules include a fuel pump in a reservoir that is mounted in a fuel tank. A fuel supply line is provided to deliver fuel pumped by the fuel pump to an engine or a high-pressure fuel pump. Typically, a check valve is provided in a fuel supply line to prevent fuel from returning to the reservoir. In addition, a separate regulator or pressure relief valve is typically provided in another part of the fuel supply line to ensure that fuel is delivered to the engine at a predetermined pressure. 
   The use of a separate check valve and regulator increases the part count, assembly time, and cost of the conventional fuel delivery system. 
   Thus, there is a need to provide a coupling valve structure that combines the function of the check valve and pressure relief valve in one structure. 
   SUMMARY OF THE INVENTION 
   An object of the invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is achieved by providing a structure for a fuel supply module. The module has a fuel pump disposed in a fuel reservoir, a feed line in fluid communication with an outlet of the fuel pump for feeding fuel to an engine or high pressure fuel pump, and a return line for returning excess fuel from the engine to the reservoir. The structure includes a check valve constructed and arranged to communicate with the feed line to permit fuel to be delivered to the engine and to prevent the fuel from draining back to the fuel pump, and a pressure relief valve integrally connected with the check valve via a conduit. The pressure relief valve is constructed and arranged to communicate with the return line such that when pressure of the fuel at the check valve is outside a certain pressure range, the pressure relief valve will open to permit fuel in the conduit to enter the return line to thereby maintain fuel exiting the check valve within the certain pressure range. 
   In accordance with another aspect of the invention, a fuel supply system is provided for delivering fuel to an engine. The system includes a fuel reservoir constructed and arranged to be mounted in a fuel tank, a fuel pump disposed in the fuel reservoir, a high pressure pump constructed and arranged to deliver fuel to an engine, a feed line in fluid communication with an outlet of the fuel pump and an inlet of the high pressure pump for feeding fuel from the fuel pump to the high pressure pump, a return line for returning excess fuel from the engine or the high pressure fuel pump to the reservoir, and a coupling valve structure. The coupling valve structure includes a check valve constructed and arranged to communicate with the feed line to permit fuel to be delivered to the engine and to prevent the fuel from draining back to the fuel pump, and a pressure relief valve integrally connected with the check valve via a conduit. The pressure relief valve is constructed and arranged to communicate with the return line such that when pressure of the fuel at the check valve is outside a certain pressure range, the pressure relief valve will open to permit fuel in the conduit to enter the return line to thereby maintain fuel exiting the check valve within the certain pressure range. 
   Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood from the following detailed description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts, in which: 
       FIG. 1  is a schematic illustration of a fuel supply system incorporating a coupling valve structure provided in accordance with the principles of the present invention. 
       FIG. 2  is an enlarged front view of a coupling valve structure provided in accordance with the principles of the present invention. 
       FIG. 3  is a sectional view of the coupling valve structure of  FIG. 2 . 
       FIG. 4  is a schematic illustration of a fuel supply system incorporating a coupling valve structure provided in accordance with the principles of a second embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT 
   With reference to  FIG. 1 , a fuel supply system, generally indicated at  10 , includes fuel supply module encircled at  12 , contained inside a fuel tank  14 , and high pressure pump  16 , which is external to fuel tank  14 . Operationally, fuel from tank  14  enters a reservoir  18  of module  12  and is pumped, via fuel pump  20 , to the high pressure pump  16 , via a feed line  21 . The high-pressure pump delivers fuel into an engine (not shown). Fuel that is not used by engine or the high pressure fuel pump returns to the reservoir  18  via a return line  22 . Module  12  thus includes the reservoir  18 , the fuel pump  20 , a flange  24  and, in accordance with the principles of the invention, coupling valve structure, generally indicated at  26 . 
   With reference to  FIG. 2 , the coupling valve structure  26  is preferably a one-piece structure that is located between the flange  24  and reservoir  18 . As best shown in  FIG. 3 , the coupling valve structure  26  includes a check valve  28  integrally connected with a pressure relief valve  30  via a conduit  23 . Preferably, structure  26  is located between the fuel pump  20  and the flange  24  of supply module  20 . Alternatively, the structure  26  can be integrated with the flange  24 . The check valve  28  is preferably a conventional one-way valve permitting fuel to be pumped from the fuel pump  20  to line  21 . The check valve  28  has a spring  32  to bias a valve element  34  to a closed position preventing fuel from returning to the fuel pump  20  via line  36  ( FIG. 1 ). In the embodiment, line  36  includes a barbed fitting defining a conduit that is coupled with tubing that is connected to the fuel pump outlet. 
   In operation, pump  20  pumps fuel from reservoir  18  through the check valve  28 , through the feed lines  38  and  21  to the high-pressure pump  16  ( FIG. 1 ). In the embodiment, feed line  38  is a barbed fitting on the coupling valve structure  26  that receives tubing (not shown) that communicates ultimately with feed line  21 . Thus the fitting  38  and tubing associated therewith can be considered to be part of feed line  21 . High-pressure pump  16  is then used to direct fuel to an engine (not shown). Diesel engines typically require the use of the high-pressure pump  16  to feed the engine with fuel. However, the coupling valve structure  26  can be used with non-diesel engines, with or without a high-pressure pump  16 , depending on the application. In any event, the purpose of the check valve  28  is to prevent feed line  21  from draining such that high pressure pump  16  will minimize sucking in air at the inlet thereof. 
   The pressure relief valve  30  is constructed and arranged to continuously permit fuel in the return line  22  to return to the reservoir  18  while normally closing an end  25  of the conduit  23  that communicates with the check valve  28 . Thus, the pressure relief valve  30  is in fluid communication with the check valve  28  via the conduit  23  such that at high-pressure variations of flow delivery from the reservoir  18 , the pressure relief valve  30  will open and permit fuel in conduit  23  pass through now open end  25  to return to the reservoir  18 . This keeps the feed line  21  pressure exiting the check valve  28  within a certain pressure range to improve the performance and proficiency of the high pressure pump  16  and therefore the engine. The coupling valve structure  26  has barbed fittings  40  communicating with the pressure relief valve  30 . These fittings  40  receive tubing (not shown) that that communicates with the return line  22 . Thus, the fittings  40  and tubing associated therewith can be considered to be part of the return line  22 . When the pressure relief valve  30  is open, fuel in the conduit  23  is now free to flow into the return line  22  and back to the reservoir  18 . The pressure relief valve  30  is preferably of the conventional spring biased type, with a spring  44  selected to ensure the opening of a valve member  44  at a predetermined pressure in conduit  23 . 
   As shown in  FIGS. 2 and 3 , the check valve  28  communicates with the outlet of fuel pump  20  and with the inlet of high pressure pump  16  and the valve member  34  is preferably oriented generally vertically. In the preferred embodiment, the valve member  44  of the pressure relief valve  30  is oriented generally transversely with respect to the valve member  34  of the check valve  28 . 
   With reference to  FIG. 4 , another embodiment of the coupling valve structure  26 ′ is shown. The structure  26 ′ is identical to the structure  26  of  FIG. 1 , except that in  FIG. 4 , a check valve  46 , preferably in the form of an umbrella, is provided in fitting  40 . The valve  46  permits fluid from the engine flowing in the direction of arrow A to enter chamber  48  and thus exit the lower portion of the fitting  40 . The valve  46  prevents fluid to flow in a direction opposite the direction of arrow A. Thus, valve  46  prevents the return line  22  ( FIG. 1 ) from draining when a vehicle rollover occurs. 
   Thus, coupling valve structure  26  performs a check valve function and a pressure relief function in one integral structure, which results in several advantages, including part and cost reduction. 
   The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the following claims.