US2503048A - Means for controlling the flow of liquid fuel to prime movers - Google Patents

Description

2 Sheets-Sheet 1 R. J. IFIELD MEANS FOR CONTROLLING THE FLOW 0F LIQUID FUEL TO PRIME MOVERS F1g.1 Ilz/U 617x501@ April 4, 195oy Filed Jan. 30, 19'47 jlfwua f..

April 4, 1950 R. J. lFlELD 2,503,048

, i mms Fon coN'rRoLLING THE FLow oF LIQUID FUEL 'ro Pam: noms Filed Jan. so', 1947 2 sheets-snee; '2

a we D La m. n .9 9 1 IL a Patented' Apr. 4, 195o MEANS ron coN'raoLLrNG 'ma FLow or movin FUEL 'ro Pimm Movizns Richard J oseph'liield, Birmingham, England,` assignor to Joseph Lucas Limited, Birmingham,

England Application January 30, 1947, Serial No. 725,242 In Great Britain December 27, 1945 Section 1, Public Law 690, August 8, 1946 Patent expires December 27, 1965 4 Claims. (Cl. 15S-36.4)

This invention has for its object to provide improved means for automatically controlling the supply of liquid fuel to the combustion chamber or chambers of a prime mover, and more especially a controlling meansadapted to enable the following condition to be met, namely m=k. p. (t2-w NE where In the accompanying sheets of drawings:

Figure 1 is a diagrammatic sectional side view of a pump and means constructed in accordance with the invention for automatically controlling the supply of liquid fuel from the pump to the explanatory combustion chamber or chambers of an internal combustion prime mover, and Figure 2 is a sectional side view of a part of the prime mover.

Figure 3 is a side view, illustrating to a larger scale than Figures 1 and 2 a cam forming part of the controlling means, andFigures 4, 5 and 6 are cross sections taken respectively on the lines 4 4, 5 5 and 6 8 of Figure 3. v

Figure 7 is a sectional side view illustrating a modified feature.

In Figure 1 of the drawings a indicates a liquid fuel pump, and b indicates means for automatically controlling the supply of liquid fuelr from the pump to the combustion chamber or chambers as c of an internal combustion prime mover, such as that illustrated in part by Figure 2.

The pump a comprises a rotary cylinder block d arranged in a casing e and having formed around its axis a plurality of bores as f in each of which is arranged a reciprocatory plunger as n. The cylinder block d is adapted to be driven in any convenient manner through the medium of a shaft h. During rotation of the cylinder block a the plungers g are moved in one direction by an angularly movable swash plate i and in the opposite direction by springs as j, the latter being situated in the bores f, and serving to hold an end face of the cylinder block in contact with a flat seating k in the casing e. The seating k is formed with a fuel delivery outlet m, and with a, fuel inlet'(not shown).

The combustion chamber of each combustion chamber c is provided at one end with a fuel injection nozzle n, and is surrounded by an air jacket o, air being supplied under pressure to this end of the combustion chamber and to the air jacket by a blower p. l

In constructing the controlling means b in accordance with the invention, I employ a hollow body part q having an inlet r and outlet s whereby the body part can be connected in a liquid fuel pipe system t between the pump a and the nozzle or nozzles n. Between the inlet r anti outlet s there is provided in the body part q an orifice u through which liquid fuel can flow from the inlet -to the outlet, and the effective area of this orifice is variable by an axially slidable plug v having one end shaped to a tapered or other appropriate configuration, this end beingk located in the orifice. Preferably and as shown a second orifice w through which liquid fuel can flow from the inlet r to the outlet s is arranged in parallel with the orifice u. The second orifice is formed by an axial bore in the plug v, and its effective area is variable by an adjustable (but otherwise sta# tionary) plug x of tapered or other appropriate form carried by the body part and having one end extending into the adjacent end of the bore in the plug v. At one end the plug v-is formed with a piston y which is contained in a cylindrical chamber z in the body part q, the piston being loaded by a. spring 2 which (through the medium of a stem 3) tends to move the plug in the direction for reducing the effective areas of both orifices u, w.

In the body part q, and in communication with the inlet 1'; are provided two passages 4, 5. The passage I serves to connect the inlet r tothe orifice u under the control of a valve 6 to be described more fully later. The other passage 5 serves to connect the inlet 1 to one end of the cylindrical chamber z, and is controlled by an adjustable choke 1. From this end of the chamber z liquid fuel can pass through holes 8 in the plug 1J to the orifice w within the plug. Also liquid fuel can pass through a restricted orifice 9 in the piston y, or a restricted passage in the wall of the chamber e, to the other end of the chamber. The latter end of the chamber e is formed with a vent I0 which is controlled by a closure member Il on one arm of a bellcrank lever I2. The other arm of the lever I2 supports one end of the spring 2 acting on the piston y, and is loaded by a pair of opposedcapsules I3, Il, the capsule I3 being evacuated, and the 'capsule I4 being open to a pipe connection I5 to which air under pressure can be supplied by the blower p through a pipe I6 connected to the inlet end of the air jacket. or one o! the air jackets o. Also a second spring l1 may be arranged to act on the side of the last mentioned lever arm opposite to that supporting the nrst spring 2, the pressure exerted by .the second spring'being adjustable by a screw i3. The pressure of the air delivered by the blower p tends, by its action on the capsule i4, to move the lever i2 in the direction for opening the vent i0, and thereby allowing liquid to escape from the adjacent end of the chamber z. This causes the pis-rton y to be moved by the liquid pressure in the other end of the chamber z in the direction for increasing the eective areas of the orifices u, w.

At the outlet side of the orifices u, w above mentioned there is formed in Athe body part q a branch passage il lleading from the outlet s to the interior of a capsule 2li. Against the closed end of the capsule. `23 bears one end of a lever 2| which at its other end carries a closure member 22 for controlling la vent 23 associated with fluidoperated means (hereinafter referred to) whereby the rate of output of the pump a is varied. Also the capsule 2l is contained in a chamber 24 formed in the body part q and communicating through a passage 25 with the inlet r. Consequently the capsule 2l is subject to the difference of fluid pressure (or pressure drop) between the inlet r and outlet s, and this drop is utilised to actuate the lever 2l for controlling the vent 23 and, hence, the rate of delivery of the pump a.

The above mentioned fluid-operated means for varying the rate of output of the pump a may be of any convenient form. In the example shown it comprises a piston 29 which is loaded at one side by a spring 21, and is adapted through the medium of a rod 23 to vary the angle of the swash plate i of the pump a. The piston 26 is conto one' end of a rotatable but axially immovable spindle 42 which at its other end is attached to a control lever 43, the latter being movable manually in accordance with the required temperature (t2) of the hot gases at the outlet end c1 of the combustion chamber or chambers c. Near its other end the rod 33 is loaded by a spring 44, and this end of the rod is provided with a multistart screw thread 45 which engages a complevmentary screw threaded nut 43, the latter being formed on a. piston-like member 41 which is slidable but non-rotatable in a chamber 43 on the body part q, and which is subject to iiuid-operated means responsive to the temperature (t1) of the air delivered by the blower p. Such uidoperated means comprise a plunger 49 which is formedon or secured to the side of the pistonlike member 41 remote from the nut 46, and is slidable in one end of a bore 50 formed in the adjacent end of the chamber 43, the other end of the bore being adapted for connection by a pipe 5i to a thermometer bulb 52- in the inlet end of the air jacket o associated with the combustion lchamber or onev of the combustion chambers c. The bore 53, pipe 5i and thermometer bulb 52 are filled with any suitable thermometer liquid through a nipple 53 on the chamber 43. The configuration of the cam-like surface 33 is such that the endwise movement of the rod 39 which is dependent on t1 and the angular position of the tz control lever 43 causes' the loading of the spring 3'4 to vary as the square of this movement and the spring loading is divided by an amount tained in a cylinder 29 having both ofits ends in communication through a restricted passage 3l. At the end remote from the spring 21, the cylinder 29 is connected by a passage 3| to the pump outlet m, or other source of liquid under against the action of its loading spring 21 by the fluid pressure acting on the opposite side of the piston, the movement being continued until the vent is again closed. The arrangement of the capsule 20 above mentioned is such that when the pressure drop across the orifices u, w exceeds some predetermined amount the vent 23 is opened to enable the output of the pump a to be reduced until the normal pressure drop is restored. y

So far I have described how the variable orifices u, w are variable in response to blower pressure..

and have thereby shown how one of the desired conditions is satisfied. I will now describe the manner in which the above mentioned valve 6 between the inlet r and the oriilce u is controlled.

The valve 6 is adapted to be held on its seating by a spring 34 and to be moved of! its` seating by the pressure of the liquid in the inlet r. To enable the force exerted by the/spring 34 to be varied, the spring serves to connect the valve i to a drag link 35 which is acted on by .one end of a lever 35, the other end of this lever being acted on by a thrust piece 31 which is supported by a tapered cam-like surface 38 on a slidable and rotatable rod 39. At one end the rod 39 is slidably connected by a tongue 45 and slot 4| depending on the angular position ofthe tz control lever. The spring loading is varied through the control lever 43 by the attendant to the appropriate t: setting, and the t1 correction is made automatically. Y

Instead of employing the cam surface above described I may employ the modication shown in Figure 7, in which parts similar or analogous to those above Ydescribed are indicated by the same reference characters suiilxed by -1. In this modiiication the plunger 491 is adapted to act on the rod 391 through the medium of a pivotal cam 541 having an operative surfacesuch that the endwise movement impartedto the rod by the plunger in response to t1 is proportional to the square ofthe plunger movement. This enables the shape of the cam-like surface 381 on the rod 391 to be simplied.

By this invention. the desired control of the rate of fuel supply to the combustion chamber, and particularly a control which satisfies the equation above mentioned can nbe obtained in a convenient and reliable manner. The invention is not, however, restricted to the examples described, as subordinate details may be modified to Vsuit dierent requirements.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

l. Liquid fuel controlling means having in combination coaxially arranged and relatively movable members forming a variable orifice,'a liquid fuel inlet passage leading to o ne side of said variable orifice, a liquid fuel outlet passage communicating with the other side of said variable orifice, means for controlling the supply of liquid fuel to said inlet passage in response to the pressure drop in-liquid fuel flowing from said inlet passage to said outlet passage through said oriiice, means responsive to air pressure for varying the effective area of said oriiice by causing relative movement of the members forming said orifice, a valve arranged in said inlet passage for controlling the flow of liquid fuel therevalve.

2. Liquid fuel controlling means having in combination coaxially arranged and relatively movable members forming a variable orifice, a liquid fuel inlet passage leading to one side of said orifice, a liquid fuel outlet passage communicating with the other side of said orifice, means for controlling the supply of liquid fuel to said inlet passage in response to the pressure drop in liquid fuel owing from said inlet passage to said outlet passage through said orifice, means responsive to air pressure for varying the effective area of said orice by 'imparting relative movement to the members forming said orifice, a valve arranged in said inlet passage for controlling the flow of liquid fuel therethrough, a slidable and rotatable control member provided with a camlike surface, a spring acting on said valve, a thrust piece through which the loading o'f said spring is variable by said cam-like surface, a manually operable lever for imparting to said control member rotational adjusting movement dependent on a required temperature condition,

A- and uuid-operated means for imparting to said member sliding movement dependent on another temperature condition. v

3. Means 6s claimed in claim 2, in which the fluid-operated means comprises a plunger responsive to fluid pressure, and having a screw thread connection with the slidable and rotatable member, so that the latter is slidable with but capable of movement relatively to the plunger.

4. Means as claimed in claim 2, in which the fluid-operated means comprise in combination a plunger responsive to fluid pressure, and a pivotal cam for 4transmitting movement from the plunger to the slidable and rotatable member.

- v RICHARD JOSEPH IFIELD.

REFERENCES crrnn The following references are of 'record in the le of this patent:

Number Name Date 2,405,888 Holley s Aug. 13, 1946 FOREIGN PATENTS Number l Country Date 490,978 Great Britain Aug. 24, 1938 493,174

Great Britain Oct. 4, 1938

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