WO1988009867A1

WO1988009867A1 - Fuel injection system with umbrella check valve

Info

Publication number: WO1988009867A1
Application number: PCT/US1987/003031
Authority: WO
Inventors: Ralph Oriola; Charles F. Romine; Edward O. Meisner
Original assignee: Eagle-Picher Industries, Inc.
Priority date: 1987-06-01
Filing date: 1987-11-19
Publication date: 1988-12-15

Abstract

A fuel injection system including a fuel tank (10) having an electric pump (11), a fuel injector (13), lines (12), (14) for circulating gasoline from the fuel tank to the injector and back to the fuel tank and an umbrella check valve (15) between the pump and the fuel injector.

Description

Fuel Injection System with Umbrella Check Valve

This invention relates to an automobile fuel injection system, and particularly to the one-way check valve between the fuel pump and the fuel injec¬ tor. Fuel injection systems for automobiles include a fuel tank, a vane-type electrical fuel pump in the tank, an outgoing fuel line to the injector, and a return line to the tank. A one-way check valve is located between the pump and the injector. When the ignition is on, the pump continuously circulates fuel, through the check valve, to the injector and back to the tank. The one-way check valve provides assurance that when the ignition is not on, the line between the check valve and the injector will remain full of fuel and the fuel will not drain back into the tank.

The check valves for the fuel injection system thus described have spring-loaded ball valves. These check valves produce an undesirable hum at a frequency which is dependent upon the rpm and number of vanes of the vane-type electric fuel pump. Almost any type of pump will create undesirable vibrations. The check valve hum is particularly noticeable in the rear seat of a vehicle. The objective of the invention has been to provide a check valve for a fuel injection system that functions quietly and eliminates the undesirable noise heretofore produced by the spring-loaded ball check valve and eliminates a spring.

The objective of the invention is attained by employing an umbrella valve as a check valve in the system. The umbrella valve is formed in part by -a tube having an internal ring presenting an axial hole. The umbrella valve is an elastomer having an umbrella- shaped top positioned at one side of said ring and adapted to cover the opening to prevent fluid flow in one direction through the opening. Structure is provided for holding the umbrella-shaped top over the opening formed by the axial hole. In one embodiment, a stem extends from the center of the umbrella-shaped top through the hole. The stem has a grommet section whose dimension exceeds the diameter of the hole and which bears against the ring to hold the check valve in position with the umbrella-shaped top pressing against the opposite side of the ring. In an alter¬ nate embodiment, a retainer ring is fixed in the passageway at the outlet side of the seal. The seal engages that retainer ring and is prevented from moving away from the axial hole in an axial direction.

The umbrella-shaped top is sufficiently resilient and flexible as to permit the passage of fluid past it when the pump is in operation. When the ignition is off and the pump is deenergized, fuel pressing against the convex side of the umbrella- shaped top prevents fluid flow back from the injector to the pump, thus keeping the line to the injector full of fuel. The use of a soft, flexible elastomer as the movable element eliminates the undesirable hum heretofore caused by the spring-loaded ball check valve. The invention will be more readily under¬ stood from the following detailed description taken in conjunction with the accompanying drawings in which:

Fig. 1 is a diagrammatic view of a fuel injection system; Fig. 2 is a cross-sectional view of one embodiment of the valve;

Fig. 3 is an end view taken along lines 3-3 of the umbrella valve of Fig. 2;

Fig. 4 is a cross-sectional view of an alternative embodiment of the valve; and

Fig. 5 is a cross-sectional view taken along lines 5-5 of Fig. 4.

Fig. 6 is a cross-sectional view of another alternative embodiment. In Fig. 1, the fuel injection system is diagrammatically shown. It includes a fuel tank 10 for gasoline. An electric fuel pump 11 is disposed in the bottom of the gas tank. The fuel pump 11 is connected by a line 12 to an injector 13. The in- jector is a known system of nozzles and distribution means by which the fuel is injected into the engine cylinders in timed relation to the firing cycle of the engine. A return line 14 connects the injector back to the gas tank. A one-way check valve 15 is disposed in the line 12 between the electric pump and the injector. The valve is oriented to permit flow from the pump through the valve to the injector in line 12, the gasoline being continuously circulated back to the tank through the line 14.

The valve 15 is positioned in the line 12 by means of tubes 20 and 21 forming a part of the line

12. The tubing is secured to a metallic tubular valve housing 25 having a small diameter inlet 26 and a large diameter outlet 27. Between the inlet 26 and outlet 27 is an internal ring 28 which presents a valve seat 30 and a hole 31. The check valve is quite small. A typical diameter of the outlet is § inch, the diameter of the inlet is 0.350 inch and the dia e- ter of the orifice or hole formed by the ring 28 is i inch. The ring thickness is about .060 inch.

The umbrella valve is indicated at 35 and includes an umbrella top 36 that is integral with a stem 37. The material is a rubber-like fluoro sili- cone elastomer or fluoro elastomer that is resistant to gasoline having a durometer in the range of 50 to 80. The stem has radially-projecting grommet sec¬ tions 40 whose transverse dimension is greater than the diameter of the hole 31. For example, the maximum dimension across the grommet sections 40 is about 0.300 inch. On each side of the grommet sections are flutes 41 through which fuel may pass to reach the underside of the umbrella top 36. The umbrella top has a flat, circular rim 43 which normally bears against the valve seat 30. The rim 43 is spaced from the grommet 40 a distance slightly less than the 0.060 inch thickness of the ring 28 so that when the umbrella valve is in posi¬ tion, the rim 43 is held in engagement with the valve seat 30.

In the operation of the valve, when the pump is operating, gasoline flows through the flute-like passageways 41 to the undersurface of the umbrella top 36. The umbrella top is caused to flex in an axial direction to permit the fuel to flow around the valve and into the outlet 27 of the housing 25. When the fuel pump is deenergized, the umbrella top relaxes and seats against the valve seat 30. Fuel in the line 12 between the valve 15 and the injector will tend to flow back toward the fuel pump. That flow will be checked by the umbrella top. The greater the pressure on the umbrella top, the greater its pressure against the valve seat 30. Because the movable element, namely, the umbrella valve 35, is a soft, resilient elastomer, the pulsation of the gasoline as caused by the vane-type fluid pump may cause the umbrella valve to flex slightly, but it will do so silently. An alternative embodiment of the valve is shown in Figs. 4 and 5. The housing 25 has an inlet 26 and an outlet 27. Between the inlet and outlet is a ring 50 having an opening 51. As best shown in Fig. 5, the opening 51 has four lobes 52. The umbrella valve 55 has a flexible top 56 as before and a stem

57. The stem, however, terminates in a solid circular grommet 58. The opening 51 has four small diameter arcuate segments 59 against which the grommet 58

5 bears. There could be fewer or greater segments depending on fuel flow required. The lobes 52 are substantially unobstructed by the grommet section and, hence, allow passage of a large flow of fuel, the flow being substantially greater than that permitted by the 0 valve of the first embodiment. There could be fewer or greater lobes depending on the fuel flow required. Also, the openings could be one or more circles or kidney-shaped holes formed in the ring 50 instead of the lobes. 5 In the alternative embodiment of Fig. 6, the umbrella top has no stem which is captured in the opening. Rather, the umbrella top in the form of a thin concave-convex diaphragm is as shown at 60 in Fig. 6. A retainer ring 61 is mounted on a shoulder

2062 in the outlet 27 of the housing 25. The retainer ring has multiple holes 63 therethrough to permit the passage of fuel. The retainer ring has a hub 64 against which the center of the umbrella top rests to hold the umbrella top in the position shown in Fig. 6. 25 It can be seen from Fig. 6 that the retainer ring blocks movement of the umbrella valve in the direction of the flow but permits its peripheral portion 65 to flex away from the seat 66 to permit fuel flow in the direction shown by the arrow 67. Movement of the umbrella valve is blocked by its engagement with the hub 64 of the retainer ring 61.

This embodiment allows the elimination of the stem section of the seal. Its advantages are a much larger inlet port because of the elimination of the restriction at the opening normally covered by the seal. There is the capability of adjusting the pressure of the valve on its seat by adjustment of either the axial length of the seal pocket (length between seal seat and retainer seat) , or the length of the hub on the retainer which bears on the umbrella seal. This allows for adjustment of the lip opening pressure and back flow with different seal materials.

The seal retainer is press-fit into the outlet of the valve housing and is seated on a counterbore or shoulder 62 on the outlet housing. Since this seat is on the discharge side of the valve, the fit of the retainer into the bore does not need to be leak-proof. This has an additional advantage to the seal manufacturer in that it eliminates the mold undercut required with the version that has the umbrella top and stem.

From the above disclosure of the general principles of the present invention and the preceding detailed description of a preferred embodiment, those skilled in the art will readily comprehend the various modifications to which the present invention is susceptible. Therefore, we desire to be limited only by the scope of the following claims and equivalents thereof.

Claims

What is claimed is:

(1) In an automotive fuel injection system including a fuel tank having an electric pump and a fuel injector, a one-way check valve mounted between said fuel pump and said fuel injection system compris¬ ing: an elongated tube, an inwardly-directed ring intermediate the ends of said tube, said ring having a surface on one side forming a valve seat, said ring defining a hole in the center of said tube, an elastomeric umbrella valve having an umbrella top and an umbrella stem, said umbrella stem having a grommet section spaced from said umbrella top and having a transverse dimension greater than the diameter of said hole, said stem projecting through said hole and said umbrella valve being held in position by the engagement of said umbrella top with said valve seat and said grommet with the other side of said ring, means forming a passageway for fuel past said grommet section and through said hole to the concave side of said umbrella top.

(2) A valve as in claim 1 in which said ring is about 0.05 inch thick and the distance between the rim of said umbrella top and said grommet section is about 0.060 inch, whereby said umbrella valve when posi- tioned in said hole resiliently biases the rim of said umbrella top against said valve seat.

(3) A check valve as in claim 1 in which said passageway-forming means comprises at least two flutes formed in said stem alongside two grommet sections.

(4) A check valve as in claim 1 in which said passageway-forming means comprises a plurality of recesses spaced around said ring to enlarge the area of said hole.

(5) In an automotive fuel injection system including a fuel tank having an electric pump_# and a fuel injector, a one-way check valve mounted between said fuel pump and said fuel injection system compris- ing: an elongated tube, an inwardly-directed annular shoulder intermediate the ends of said tube, said annular shoulder providing a surface forming a valve seat, a circular elastomeric valve having a peripheral edge portion normally engaging said valve seat, and means holding said elastomeric valve in position with said peripheral portion resting on said shoulder and adapted to move from said shoulder to permit the passage of fuel from said tank to said fuel injector.

(6) A check valve as in claim 5 in which said elastomeric valve is a thin concave-convex diaphragm.

(7) A check valve as in claim 6 in which said holding means is a retainer ring fixed across said tube and contacting the convex side of said diaphragm to hold the concave side of said diaphragm against said shoulder.