US2706490A - Variable retraction valve - Google Patents

Description

VARIABLE RETRACTION VALVE 2 Sheets-Sheet 1 Filed Jan. 18, 1950 $306 E7722? G7Z 6 5/ 2d57 jzzzr Free/725072 April 19, 1955 E. GRIESHABER ET AL 2,706,490

VARIABLE RETRACTION VALVE Filed Jan. 18, 1950 2 Sheets-Sheet 2 United States Patent 9 2,706,490 VARIABLE RETRACTION VALVE Emil Grieshaber and Kurt Froehlich, Milwaukee, Wis., assignors to Nordberg Manufacturing Co., Milwaukee, Wis., a corporation of Wisconsin Application January 18, 1950, Serial No. 139,202

1 Claim. (Cl. 137516.27)

Our invention relates to fuel injection control means for internal combustion engines and, in particular, to delivery valves therefor, and has for one purpose to provide an improved retraction valve assembly for controlling the flow of fuel to internal combustion engines.

Another purpose is to provide a unitary retraction valve assembly, in which a single movable valve member is employed to provide a wide variation in fuel delivery.

Another purpose is to provide a retraction valve usable with Diesel engines and adapted efficiently to control the delivery of liquid fuel in small quantities.

Another purpose is to provide a simple unitary retraction valve utilizable to control the flow of liquid fuel to a dual fuel engine adapted to employ liquid fuel, gas fuel, or a combination of the two.

Another purpose is to provide a simple unitary retraction valve of eflicient operation.

Another purpose is to provide a displacer piston located below the valve seat, which relieves the pressure in the fuel line after the fuel injection is accomplished.

Another purpose is to provide a bypass or relief around the displacer piston whereby, with a small amount of fuel, the valve does not lift the full amount which is! provided for by the displacer piston.

Other purposes will appear from time to time in the course of the specification and claim.

We illustrate the invention more or less diagrammatically in the accompanying drawings wherein:

Figure 1 is an axial section through the retraction valve assembly; I

Figure 2 is a section along the lines 2-2 of Figure 1;

Figure 3 is a section similar to 2-2 through a variant form of the invention;

Figure 4 is a section similar to 22 through a variant form of the invention;

Figure 5 is a side elevation of a modified valve structure;

Figure 6 is an axial section through another modification of the retraction valve;

Figure 7 is a section along the lines 7-7 of Figure 6;

Figure 8 is an axial section through still another form of the unitary retraction valve; and

Figure 9 is an axial section through a valve and pump assembly illustrating its application to a fuel injection valve.

Like parts are indicated by like symbols throughout the specification and drawings.

Referring to the drawings, and for example to Figure 9, A generally indicates a fuel pump assembly, the details of which do not of themselves form part of the present invention, and B indicates a fuel injection assembly, the details of which likewise do not form part of the present invention.

Suitably secured to the pump assembly A, and extending into one end thereof, we illustrate an outer sleeve 1 apertured to accommodate an inner sleeve 2 and a valve seat element 3, the sleeves 1 and 2 and the element 3 constituting a housing or the like. The valve seat element 3 has an outwardly extending flange 3a abutting an inner shoulder 1a of the member 1. It is confined in the position in which it is shown in Figure 9 by the abu tting end 2a of the sleeve 2. A valve chamber 4 1s shown as formed within the sleeve 2. 5 indicates a nut threaded into the interior of the sleeve 1 and having an end 5a abutting an outer ledge 2b of the member 2. Thus, when the nut 5 is tightened, the sleeve 2 is thrust against the flange 3a of the valve seat element 3, and the valve seat element is firmly thrust against the inward ledge 1a 2,706,490 Patented Apr. 19, 1955 'ice of the member 1. 6 and 7 are any suitable packing rings or members, whereby leakage around the valve seat member 3 is prevented.

The sleeve 1 and its associated parts is shown as in screw-threaded relation with a surrounding portion of the pump assembly A. 8 is any suitable pressure ring confining any suitable gasket or packing 9. The chamber has a bore 3b in the valve seat element 3 which is aligned with and in communication with any suitable pump chamber 20. The valve chamber 4 is in communication with the fuel delivering passage 4a adapted to deliver fuel to any suitable duct 21 extending to the injection valve assembly B.

30 generally indicates a retraction valve body. In the form of Figure 1, the body 30 has a valve head 31 with a conic face or valve surface 32 opposed to a conic valve seat 321: formed about the bore 3b of the valve seat member 3. The valve stem 33 is shown as generally cruciform in cross-section with guide vanes having surfaces 33a which engage the inner surface of the cylindrical wall of the bore 3b and thus guide the valve body member 30. Between the conic face 32 and the valve stem 33 is a displacer piston portion 34. As will be clear from Figures 1 and 2, the displacer piston 34 has a generally cylindrical outer surface slightly inwardly spaced from the opposed surface of the cylindrical bore 3b of the member 3. Thus, after the valve body has been lifted, and while the displacer piston is within the cylindrical bore of the member 3, the gap or space between it and the bore provides a bypass or relief around the piston. In the form of Figure l, the upper ends of the vanes 33 are shown as curved as at 33b.

It will be understood that we can widely vary the shape of the retraction valve element or body to provide leakage or bypassing by a variety of means. Thus in Figure 3, still in connection with a cruciform valve stem, we form the displacer piston 35 with diametrically opposed flattened portions or leaks" 35a. The number and shape of the flattened portions can be varied or controlled to provide the desired flow.

Similarly, in Figure 4, instead of employing flattened portions, we may provide clearance indentations 36a of different shape, for example in the form of notches in the edge of the displacer piston 36.

In Figure 5, we illustrate still a further variant form, otherwise identical with the form of Figure 3, in which the displacer piston 37 is flattened as at 37a and has its lower surface inclined as at 37b, to provide a progressively varying clearance as the valve body lifts from the valve seat.

In Figures 6 and 7, we illustrate a form in which the valve stem 40 is provided with a center bore 41. The body may be centered or guided, for example by vanes 42 which snugly engage the interior of the bore 3b of the member 3. The displacer piston 43 also snugly engages the interior of the bore and the leakage or relief is provided above the displacer piston 43 by a plurality of radial passages 45.

In the form of Figure 8, we illustrate a stem 50, with an interior axial passage 51. The stem may snugly engage the bore or member 3. Two displacer pistons 52, 53 are employed. In effect, this amounts to adding a small displacer piston 53 above the single displacer piston which is shown at 43 in Figure 6. The result is that, instead of starting with a theoretical zero displacement and working up to a maximum, we begin with an initial slight displacement, which may be advantageous under certain conditions of engine operation.

In all forms of our device there is thus a provision for a bypass around a displacer piston, the effect being that with small amounts of fuel, the valve will not lift the full amount which is provided by the displacer piston. It will be understood that at full lift, the valve operates like any other valve with displacer piston.

In each form, it will be understood that the valve body is normally held in or urged toward closed position by the coil spring 60, housed in the space or valve chamber 4. The valve chamber is shown of somewhat different contour in Figures 1 and 9, it being a matter of choice as to the length of the spring and the contour of the valve chamber employed.

Our invention is applicable to the delivery of liquid fuel in Diesel engines operating on liquid fuel and also in engines operating on gaseous fuel with a liquid pilot oil for igniting the gaseous fuel. In other words, it will be understood that our invention may be employed in a variety of situations in which close control of a relaburning gaseous fuel, it will be understood that the amount tively small volume of pilot fuel is desired. In engines burning gaseous fuel, it will be understood that the amount of fuel oil used for igniting the gas is so small that the ordinary delivery valve with constant retraction will not work satisfactorily. In the use of our invention, it will be understood that a certain amount of retraction on the delivery valve corresponds to a certain pressure drop in the pressure line to the fuel nozzle. For pilot oil, the pressure in the fuel line is barely above the pressure set by the spring in the nozzle, whereas for full load Diesel operation the pressure in the fuel line is usually more than twice the pressure set by the spring in the fuel nozzle. Thus, it should be possible to operate without retraction for pilot operation and have an appropriate amount of retraction for Diesel operation. This result we obtain by employing one or another of the bypass arrangements around the displacer piston which are above described.

It will be realized that whereas we have described and claimed a practical and operative device, nevertheless many changes may be made in the size, shape and disposition of parts without departing from the spirit and scope of our invention. We therefore wish our description and drawings to be taken as in a broad sense illustrative or diagrammatic, rather than as limiting us to our precise showing herein.

We claim:

In a retraction valve assembly adapted to be connected between a fuel injector and a fuel pump, the assembly being constructed and arranged to control the flow of 4 fuel to an internal combustion engine, the assembly including a member defining an inlet bore adapted for communication with the fuel pump, a valve seat formed in the bore, a retraction valve body in the bore movably disposed therein and having a valve head opposed to the seat, spring means normally urging the valve head toward the seat so as to close the bore, a valve stem on the valve body with a portion having a diameter generally the same as the bore, a displacer piston on the stem spaced from the stem portion by an annular channel, the channel defining a sharp circumferential edge on the piston which cooperates with the bore to instantaneously regulate the fuel flow, and a limited relief passage past the displacer piston when the piston is in the bore, a second annular channel adjacent the valve head, said limited relief passage including an axially disposed passage in the stem, and at least one radially disposed passage communicating with the axial passage and with the second mentioned annular channel, said displacer piston having generally the same diameter as the bore, and passages communicatligig with the first mentioned annular channel and the inlet ore.

References Cited in the file of this patent UNITED STATES PATENTS 1,139,646 Davies May 18, 1915 1,730,322 Garten Oct. 1, 1929 2,090,688 Lindberg Aug. 24, 1937 2,090,781 Camner Aug. 24, 1937 2,163,313 Voit June 20, 1939 2,327,574 Zinkil Aug. 24, 1943 2,612,841 Lasley Oct. 7, 1952 FOREIGN PATENTS 576,317 France 1924 609,878 France 1926 493,909 Germany 1930

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