Patent Publication Number: US-2023146010-A1

Title: Venturi pump system for a fuel sending unit

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
     Not Applicable 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates generally to a pump for a vehicle fuel circuit, and more specifically, to a venturi pump configured for placement in a fuel tank and operatively connectable to a lift pump located outside of the fuel tank. 
     2. Description of the Related Art 
     Many gas or diesel powered vehicles include a fuel circuit that circulates fuel from a main fuel tank to the engine. In many fuel circuits, the fuel is pumped out of the fuel tank via a lift pump and delivered to a fuel injection system, wherein the fuel is injected into the engine for consumption. For instance, lift pumps have found widespread adoption in modern diesel trucks to create a constant supply of low-pressure fuel for the diesel injection system. Any unused fuel may be returned to the fuel tank via a return line for later use. Many fuel tanks include a fuel sending bucket located within the fuel tank reservoir, from which the fuel is drawn by the lift pump. 
     A common issue associated with use of an aftermarket lift pump, particularly in diesel trucks, occurs when the suction side of the lift pump drains the fuel sending bucket in the fuel tank, which results in the lift pump drawing air instead of fuel. This issue, commonly referred to as the “quarter tank issue,” results in the diesel injection system of the truck not receiving the correct amount of fuel pressure needed to supply the engine. Consequently, the truck&#39;s engine may enter a reduced power mode or shut off due to fuel starvation. This issue may commonly occur when the fuel level is at or below a certain level, typically below one quarter of the fuel tank capacity. 
     To solve this quarter tank issue, fuel systems may utilize several methods to maintain the fuel level in the fuel sending bucket (also commonly referred to as the sending unit), such as check valves in the bottoms of the bucket to allow fuel to flow in when the bucket level is lower than the rest of the tank. Additionally, some fuel sending units have internal pumps to draw fuel from outside the bucket into the bucket, with such pumps typically exceeding the capabilities of a simple check valve. Existing internal pumps are typically powered by, or include, a lift pump located in the bucket itself. However, such pumps tend to be limited in their ability to connect with more powerful pumps to deliver more fuel to the injection system than the factory pumps. 
     Accordingly, there is a need in the art for a pump for a fuel sending bucket which can be used in connection with a more powerful pump, such as a lift pump located outside of a conventional fuel tank. Various aspects of the present disclosure address this particular need, as will be discussed in more detail below. 
     BRIEF SUMMARY 
     In accordance with one embodiment of the present disclosure, there is provided a fuel system for a vehicle comprising a fuel tank defining a fuel tank reservoir therein. A lift pump is located outside of the fuel tank and is in fluid communication with the fuel tank reservoir. The lift pump includes a fluid inlet, a first fluid outlet, and a second fluid outlet, with the fluid inlet being configured to receive fuel from the fuel tank. The lift pump is configured to output fluid from the first fluid outlet at a first prescribed pressure. A venturi pump is located within the fuel reservoir and defines a venturi pump reservoir therein. The venturi pump includes a venturi jet including a drive inlet and a suction inlet. The drive inlet is configured to be fluidly connectable to the first fluid outlet of the lift pump to receive fluid therefrom at the first prescribed pressure. The suction inlet is configured to be placeable in fluid communication with the fuel tank reservoir and to draw fluid from the fuel tank reservoir into the venturi pump reservoir in response to fluid flowing through the venturi jet at the first prescribed pressure. 
     The fuel system may additionally include a lift pump suction line extending from the venturi pump reservoir to the fluid inlet of the lift pump, with at least a portion of the lift pump suction line extending outside of the fuel tank. 
     The venturi jet may be configured to generate a fluid flow through the suction inlet of 4-5 gallons per hour in response to fluid flowing through the venturi jet at the first prescribed pressure. 
     The venturi jet may include a jet outlet in fluid communication with the venturi pump reservoir. 
     The venturi pump may include a housing having an upper wall, a lower wall, and a sidewall extending between the upper wall and the lower wall, with the housing defining the venturi pump reservoir. The upper wall may include a pair of inlet openings formed therein, the venturi housing further including a pair of ramps positioned with respect to respective ones of the pair of inlet openings such that fluid entering the pair of inlet openings impinges on respective one of the pair of ramps. 
     The venturi housing may further include a rigid tube coupled to the upper wall and extending toward the lower wall. The rigid tube may include a terminal edge adjacent the lower wall, with the venturi housing further including at least one finger extending from the rigid tube, the at least one finger being configured to space the terminal edge from the lower wall. 
     The venturi pump may include a one-way valve formed therein. 
     According to another embodiment, there is provided a venturi pump for a fuel circulation system in a vehicle, with the fuel circulation system including a fuel tank having a fuel tank reservoir. The fuel circulation system additionally includes a lift pump having a first fluid outlet, with the lift pump being configured to output fuel from the first fluid outlet at a first prescribed pressure. The venturi pump includes a housing sized to be disposable in the fuel tank reservoir, with the housing having an upper wall, a lower wall, and a sidewall extending between the upper wall and the lower wall. The housing defines a venturi pump reservoir. A venturi jet is coupled to the housing and includes a drive inlet and a suction inlet. The drive inlet is configured to be fluidly connectable to the first fluid outlet of the lift pump to receive fluid therefrom at the first prescribed pressure. The suction inlet is configured to be placeable in fluid communication with the fuel tank reservoir and to draw fluid from the fuel tank reservoir into the venturi pump reservoir in response to fluid flowing through the venturi jet at the first prescribed pressure. The venturi pump additionally includes a rigid tube coupled to the upper wall and extending toward the lower wall wherein the rigid tube includes a terminal edge adjacent the lower wall. At least one finger extends from the rigid tube and is configured to space the terminal edge from the lower wall. 
     According to yet another embodiment, there is provided a method of circulating fuel through a fuel circuit in a vehicle. The method includes urging fuel from a fuel tank reservoir of a fuel tank to a lift pump located outside of the fuel tank; outputting fuel from the lift pump via a first fluid outlet, the lift pump being configured to output fuel from the first fluid outlet at a first prescribed pressure; receiving fuel output from the first fluid outlet at a venturi pump, the received fuel being at the first prescribed pressure, the venturi pump having a venturi pump reservoir and a venturi jet; and allowing the received fuel to flow through the venturi jet, with the venturi jet being configured to generate a force which draws fuel from the fuel tank reservoir into the venturi pump reservoir in response to the received fuel flowing through the venturi jet. 
     The urging step may include causing fuel to flow through a lift pump suction line extending from the venturi pump reservoir to the fluid inlet of the lift pump, with at least a portion of the lift pump suction line extending outside of the fuel tank. 
     The method may also include the step of drawing fuel from the fuel tank reservoir into the venturi pump reservoir at a rate of 4-5 gallons per hour in response to fuel flowing through the venturi jet. 
     The method may further include the step of outputting fuel from the lift pump via a second fluid outlet. The fuel output from the second fluid outlet may be received at the venturi pump reservoir. 
     The urging step may include urging fuel from the venturi pump reservoir, with the venturi pump reservoir being located within the fuel pump reservoir. The urging step may include drawing fuel in the venturi pump reservoir via a rigid tube extending into the venturi pump reservoir. 
     The present disclosure will be best understood by reference to the following detailed description when read in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which: 
         FIG.  1    is a schematic view of fuel system for circulating fuel within a vehicle, the fuel system including a venturi pump located within a fuel tank and in communication with a lift pump positioned outside of the fuel tank; 
         FIG.  2    is an upper perspective view of a venturi pump used in the fuel system of  FIG.  1   ; 
         FIG.  3    is an upper perspective view of a connection plate included in the venturi pump of  FIG.  2   ; 
         FIG.  4    is a lower perspective view of the connection plate depicted in  FIG.  3   ; 
         FIG.  5    is an upper perspective view of a main unit included in the venturi pump of  FIG.  2   ; 
         FIG.  6    is a lower perspective view of an upper wall of the main unit and a rigid tube connected to the upper wall; 
         FIG.  7    is an upper perspective view of a lower portion of the main unit, including a venturi jet extending into a venturi pump reservoir; 
         FIG.  8    is a top view of the lower portion of the main unit depicted in  FIG.  7   ; 
         FIG.  9    is a bottom view of the main unit; 
         FIG.  10    is a partial upper perspective, sectional view of the lower portion of the main unit; and 
         FIG.  11    is a partial side sectional view of the lower portion of the main unit. 
     
    
    
     Common reference numerals are used throughout the drawings and the detailed description to indicate the same elements. 
     DETAILED DESCRIPTION 
     The detailed description set forth below in connection with the appended drawings is intended as a description of certain embodiments of a venturi pump for a vehicle fuel circuit and is not intended to represent the only forms that may be developed or utilized. The description sets forth the various structure and/or functions in connection with the illustrated embodiments, but it is to be understood, however, that the same or equivalent structure and/or functions may be accomplished by different embodiments that are also intended to be encompassed within the scope of the present disclosure. It is further understood that the use of relational terms such as first and second, and the like are used solely to distinguish one entity from another without necessarily requiring or implying any actual such relationship or order between such entities. 
     Various aspects of the present disclosure are directed toward a venturi pump for use in a vehicle fuel circuit. The venturi pump is configured to be placed in a fuel tank of the and may defines a venturi pump reservoir, which may be filled by a venturi jet within the venturi pump. The venturi jet may draw in fuel from the larger fuel tank to fill the smaller venturi pump reservoir for purposes of providing an easier supply of fuel from which fuel may be drawn to supply to the engine, particularly as the fuel level in the fuel tank is low, e.g., below one-quarter of a tank. The venturi pump may be in fluid communication with a lift pump located outside of the fuel tank. The venturi pump receives fluid from an engine supply line, which is supplied by the lift pump at a generally consistent pressure. The consistent pressure allows for calculation and design of a preferred orifice size of the venturi jet to maintain a desired flow rate through the venturi pump to fill the venturi pump reservoir. 
     According to one embodiment and referring now specifically to the schematic diagram depicted in  FIG.  1   , a fuel system  10  for a vehicle includes a fuel tank  12 , a lift pump  14 , a venturi pump  16 , and a fuel injection system  18 , which may include a high-pressure fuel pump or hydraulically actuated fuel injectors. The fuel system  10  additionally includes several fluid lines (e.g., tubes, conduits, hoses, etc.) to facilitate transfer of fuel from one component to another. 
     The fuel tank  12  includes a fuel tank reservoir  20  sized and configured to receive vehicle fuel. The fuel tank reservoir  20  may be available in several sizes, such as between 10-30 gallons, depending on the size of the associated vehicle. It is contemplated that the size of the fuel tank reservoir  20  may be less than 10 gallons or greater than 30 gallons without departing from the spirit and scope of the present disclosure. 
     The lift pump  14  is located outside of the fuel tank  12  and is in fluid communication with the fuel tank reservoir  20 . The lift pump  14  may be configured to create a constant supply of low-pressure fuel for a fuel injection system  18 . According to one embodiment, the lift pump  14  includes a fluid inlet  22 , a first fluid outlet  24 , and a second fluid outlet  26 . The fluid inlet  22  is connected to fluid line  28  which extends to the fuel tank  12 , and in particular, to a venturi pump reservoir  30  located within the fuel tank  12 , to supply fuel from the venturi pump reservoir  30  to the lift pump  14 . The lift pump  14  may be configured to output fluid from the first fluid outlet  24  at a first prescribed pressure, desirable for the fuel injection system. In some vehicles, the first prescribed pressure may be between 50-60 PSI, although it is contemplated that the first prescribed pressure may be less than 50 PSI or greater than 60 PSI without departing from the spirit and scope of the present disclosure. The first fluid outlet  24  may be connected to an engine supply line  32  having a venturi supply branch  34  extending to the venturi pump  16  and a fuel injection branch  36  extending to the fuel injection system  18 . The fluid in both the venturi supply branch  34  and the fuel injection branch  36  may be at the first prescribed pressure. The second fluid outlet  26  may be an excess outlet, to return any excess fuel not exiting via the first fluid outlet  24  to the fuel tank  12 , and more specifically, to the venturi pump reservoir  30  via a lift pump return line  38 . An engine return line  39  extend between the engine/fuel injection system  18  and the venturi pump  16  to return unused fuel from the engine to the venturi pump  16 . Since the lift pump return line  38  and engine return line  39  may return excess fuel from the lift pump  14  and engine, respectively, the amount of fuel flowing through the lift pump return line  38  and engine return line  39  may vary during operation of the vehicle. 
     The venturi pump  16  is located within the fuel tank reservoir  20  and is disposable in fluid communication with the lift pump  14 .  FIGS.  2 - 11    show various views of an exemplary venturi pump  16 , with  FIG.  2    being an upper perspective view of the venturi pump  16 , which may include a connection plate  40  and a main unit  42  connected to the connection plate  40  via one or more mechanical connections, as well as via one or more fluid connections. The mechanical connections may include one or more rigid shafts  44  extending between the connection plate  40  and the main unit  42 . The rigid shafts  44  may include a threaded portion, which allows for positional adjustment of one or both of the connection plate  40  and main unit  42  along the rigid shafts  44 . In the exemplary embodiment, the threaded portion of the rigid shafts  44  are connected to the main unit  42 , such that rotation of the rigid shaft  44  relative to the main unit  42  in a first rotational direction causes the main unit  42  to move away from the connection plate  40 , and rotation of the rigid shaft  44  relative to the main unit  42  in a second rotation direction causes the main unit  42  to move toward the connection plate  40 . 
     The connection plate  40  may include an upper surface  46 , an opposing lower surface  48 , and a plurality of openings extending through the upper and lower surfaces  46 ,  48 . Each opening may include a fitting extending from the upper and lower surfaces  46 ,  48  to facilitate attachment to a respective fluid line. In particular, the connection plate  40  may include three inlet openings, and one outlet opening. A first inlet opening  50  may be placed in communication with the engine return line  39  to receive unused fluid from the engine/fuel injection system  18 . A second inlet opening  52  may be placeable in communication with the second fluid outlet  26  of the lift pump  14  to receive fuel via the lift pump return line  38 . A third inlet opening  54  may be in communication with the first fluid outlet  24  of the lift pump  14  to receive fuel therefrom via the venturi supply branch  34  of the engine supply line  32 . Outlet opening  56  may be placed in fluid communication with the lift pump  14  to supply fuel thereto. 
     The main unit  42  includes a housing  58  having an upper wall  60 , a lower wall  62 , and a sidewall  64  extending between the upper wall  60  and the lower wall  62 , with the housing  58  defining the venturi pump reservoir  30 . The upper wall  60  may include three inlet openings  66 ,  68 ,  70  formed therein to receive fluid from respective ones of the first, second, and third inlet openings  50 ,  52 ,  54  of the connection plate  40 . In particular, inlet opening  66  receives fluid from the third inlet opening  54  to receive the pressurized fluid output from the lift pump  14  via the venturi supply branch  34  of the engine supply line  32 . The inlet openings  68 ,  70  may receive fluid from the first and second inlet openings  50 ,  52 , to receive fluid from the engine return line  39  and the lift pump return line  38 . The housing  58  may additionally include an outlet opening  74 , through which fluid may exit the housing  58  to flow to the lift pump  14 , as will be described in more detail below. 
     A conduit may pass through, or be in communication with, the inlet opening  66  and connect with a venturi jet  72  to facilitate delivery of fuel under pressure to the venturi jet  72 . The fuel received via the remaining two inlet openings  68 ,  70  may flow into the venturi pump reservoir  30  to fill the venturi pump reservoir  30 . The venturi housing  58  may include a pair of ramps  76 ,  78  positioned with respect to respective ones of the inlet openings  68 ,  70  that receive fuel from the return lines  38 ,  39  such that fluid entering the pair of inlet openings  68 ,  70  from the return lines  38 ,  39  impinges on respective one of the pair of ramps  76 ,  78 . The impingement of the fuel against the ramps  76 ,  78  after passing through the inlet openings  68 ,  70  may prevent or reduce the likelihood of bubbles forming the fuel. 
     The housing  58  may also include a pair of clips  80  connected to the upper wall  60  to facilitate detachable engagement of the upper wall  60  to the sidewall  64 . 
     Referring now specifically to  FIG.  6   , the venturi housing  58  may further include a rigid tube  82  coupled to the upper wall  60  and extending toward the lower wall  62  when the upper wall  60  is attached to the sidewall  64 . The rigid tube  82  may include a terminal edge  84  positionable adjacent the lower wall  62 . The rigid tube  82  may form an internal passageway  86  within which fuel may be withdrawn from the venturi pump reservoir  30  to supply fuel to the lift pump  14 . In the regard, operation of the lift pump  14  may produce a suction force within the internal passageway  86 . The rigid tube  82  may have sufficient internal strength to prevent buckling or collapsing when the suction force is applied. 
     One or more fingers  88  may extend from the rigid tube  82 , beyond the terminal edge  84 , to contact the lower wall  62  and space the terminal edge  84  from the lower wall  62 . In the exemplary embodiment, a pair of fingers  88  extend from the terminal edge  84  in diametrically opposed relation to each other, although the number, configuration, and placement of the fingers  88  is not limited thereto. The fingers  88  may be integrally formed with the rigid tube  82  or alternatively, formed separate from the rigid tube  82  and subsequently added onto the rigid tube  82 . The space created between the terminal edge  84  and the lower wall  62  is the space through which fuel may flow from the venturi pump reservoir  30  and into the internal passageway of the rigid tube  82 . 
     The venturi jet  72  may include a drive inlet  90 , a suction inlet  92 , and a jet outlet  94  in fluid communication with the venturi pump reservoir  30 . The drive inlet  90  is configured to be fluidly connectable to the first fluid outlet  24  of the lift pump  14  via intervening conduits, such as the venturi supply branch  34 , to receive fluid therefrom at the first prescribed pressure. The drive inlet  90  may be formed as a generally cylindrical wall having an internal passageway  96  formed therein. An outer surface of the drive inlet  90  may be barbed to facilitate connection to the conduit that delivers fuel from the lift pump  14 . 
     The drive inlet  90  may be in communication with a connector body  98  that extends between the drive inlet  90  and the jet outlet  94 . The connector body  98  may generally include an arm  100 , a main portion  102 , a nozzle portion  104  and a mounting post  106 . The arm  100  is configured to extends into the drive inlet  90  to facilitate fluid-tight connection between the connector body  98  and the drive inlet  90 . In the exemplary embodiment, the connector body  98  includes an outwardly extending protrusion or rib  108  that extends circumferentially around the arm  100  and is sized to be received in a corresponding groove formed on an inner surface of the drive inlet  90 . The arm  100  includes an internal passageway that is in communication with the drive inlet  90  when the arm  100  is connected to the drive inlet  90 . 
     The main portion  102  extends from the arm  100  in generally perpendicular relation thereto. In this regard, the internal passageway extending through the arm  100  extends along an arm axis  110  that is generally perpendicular to a main portion axis  112 , along which an internal passageway of the main portion  102  extends. 
     The nozzle portion  104  is connected to main portion  102 , opposite the arm  100 , and defines an internal passageway having a tapered configuration terminating at a nozzle output. The nozzle portion  104  extends into a lower end portion of the jet outlet  94 , such that the nozzle output is located within the jet outlet  94 . The nozzle portion  104  and the jet outlet  94  are configured such that the suction inlet  92  (e.g., a gap) is formed therebetween. When the venturi pump  16  is placed within the fuel tank  12 , the suction inlet  92  is in communication with the fuel tank reservoir  20 . As such, fuel from the fuel tank reservoir  20  may pass through the suction inlet  92  and into the jet outlet  94  during operation of the venturi pump  16 . The suction applied at the suction inlet  92  may be a result of the venturi effect associated with the flow of fuel through the constricted configuration of the nozzle outlet and into the jet outlet  94 . 
     The mounting post  106  may be received within a mounting sleeve  114  formed on the housing  58  to facilitate connection between the connector body  98  and the housing  58 . 
     The venturi pump  16  may include a one-way valve  116  formed therein. The one-way valve  116  may allow fluid to flow into the venturi pump reservoir  30  from the fuel tank reservoir  20  but may restrict fluid flow from the venturi pump reservoir  30  to the fuel tank reservoir  20 . If the fuel level in the fuel tank reservoir  20  is greater than the fuel level in the venturi pump reservoir  30 , the difference in fluid pressure due to the different fuel levels may urge the fluid in the fuel tank reservoir  20  to flow through the one-way valve  116  and into the venturi pump reservoir  30  until the levels are generally balanced. However, if the level of fuel in the venturi pump reservoir  30  is greater than the level of fuel in the fuel tank reservoir  20 , the one-way valve  116  may prevent fuel from flowing out of the venturi pump reservoir  30 . The one-way valve  116  may include a plurality of openings formed in the lower wall  62 , which may be selectively covered or uncovered by a valve body (e.g., a butterfly valve) to either allow fluid flow through the openings, or block fluid flow through the openings. 
     The venturi jet  72  may be configured to generate a fluid flow through the suction inlet  92  of 4-5 gallons per hour in response to fluid flowing through the venturi jet  72  at the first prescribed pressure. However, the flow characteristics of the venturi jet  72  may be varied, e.g., less than 4 gallons or greater than 5 gallons, without departing from the spirit and scope of the present disclosure. 
     In operation, the lift pump  14  is actuated to draw fuel from the venturi pump reservoir  30  to the lift pump  14  via the lift pump suction line  28 . The lift pump  14  outputs fuel at a generally constant pressure from the first outlet  24  to the engine supply line  32 . Fuel flows at the elevated pressure along the fuel injection branch  36  to the fuel injection system  18 , and the venturi supply branch  34  to the venturi pump  16 . Any excess fuel, e.g., fuel not needed to flow to the fuel injection system  18 , exits the second outlet  26  of the lift pump  14  along the lift pump return line  38 . Likewise, any fuel not used by the fuel injection system  18  is returned to the venturi pump  16  via the engine return line  39 . 
     At the venturi pump  16 , fuel is received via the respective inlets, with the fuel received from the lift pump return line  38  and the engine return line  39  being flowing over the ramps  76 ,  78  to prevent bubbles from forming in the fuel. 
     The fuel received form the venturi supply branch  34  is received at an elevated pressure and is received at the jet inlet  90 . The pressurized fuel flows through the jet inlet  90 , through the arm  100  of the connector body  98 , through the main portion  102  of the connector body  98 , and then into the nozzle portion  104  of the connector body  98 . The constricted passage in the nozzle portion  104  causes the fuel to flow at a greater speed as it exits the nozzle portion  104  to generate a venturi effect, and to impart a suction force on the suction inlet  92 . The suction force causes fuel to enter the jet outlet  94  from the fuel tank reservoir  20  and join the fuel that has exited the nozzle portion  104  and flow through the jet outlet  94 . As the fuel exits the jet outlet  94 , the fuel enters the venturi pump reservoir  30 . 
     The incorporation of the venturi pump  16  within the fuel tank reservoir  20  allows the level of fuel in the venturi pump reservoir  30  to remain at a level that is easier to draw from relative to the lower level of fuel in the fuel tank reservoir  20 . The ability to keep an elevated fuel level in the venturi pump reservoir  30  is particularly beneficial when the level of fuel in the fuel tank  12  drops below a quarter of a tank and the fuel may slosh around the fuel tank  12  when the vehicle is turning or quickly changes speed. 
     The particulars shown herein are by way of example only for purposes of illustrative discussion and are not presented in the cause of providing what is believed to be most useful and readily understood description of the principles and conceptual aspects of the various embodiments of the present disclosure. In this regard, no attempt is made to show any more detail than is necessary for a fundamental understanding of the different features of the various embodiments, the description taken with the drawings making apparent to those skilled in the art how these may be implemented in practice.