US2530507A - Fuel injection apparatus and control - Google Patents

Description

1950 J. F. CAMPBELL 2, 0 I

FUEL INJECTION APPARATUS AND CONTROL Filed Oct. 25, 1945 3 Sheets-Sheet 1 l6. 4 INVENTOR.

Joy 5 CAMPBELL 7 BY M ilw flw Nov. 21, 1950 J. F. CAMPBELL FUEL INJECTION APPARATUS AND CONTROL 3 Sheets-Sheet 3 Filed Oct. 25, 1945 6 INVENTOR.

JOHN F CAMPBELL zs w Arron/ways Patented Nov. 21, 1950 FUEL INJECTION CON APPARATUS AND I TROL John F. Campbell, Euclid, Ohio Application October 25, 1945, Serial No. 624,475

14 Claims. 1

This invention relates to fuel injection apparatus for internal combustion engines and, as one of its objects, aims to provide improved apparatus of this kind which is of a relatively simple construction and which will be efficient and reliable in operation and will eliminate vapor lock and other disadvantages encountered in fuel injection apparatus heretofore devised.

Another object of the present invention is to provide improved fuel injection apparatus, in which a pumping member and a control valve are so located relative to a driven shaft that both can be actuated directly from such shaft.

A further object of this invention is to provide improved fuel injection apparatus for a multiple cylinder internal combustion'engine, in which a group of pumping members and a similar group of control valves are disposed around a driven shaft from which they are actuated in a direct and uniform manner.

Yet another object of the invention is to provide improved fuel injection apparatus of this character, in which the fuel inlet means serving the pump chambers and their control valves is such that a solid body of liquid fuel will always be supplied to the pump chambers and the troublesome tendency to create a vacuum therein during the pumping operation will be eliminated.

Still another object of this invention is to provide improved fuel injection apparatus of the character mentioned, in which cam means for actuating the inlet valves is automatically adjustable relative to the driven shaft in response to changes in the fuel requirements of the engine.

It is also an object of the present invention to provide improved fuel injection apparatus of this character, in which the adjustable valve actuating cam has a variable contour which will produce a desired variation in the fuel injection period relative to the engine cycle.

Still another object of this invention is to provide improved fuel injection apparatus of the kind referred to, in which the automatic adjustment of the valve actuating cam is accomplished by pressure sensitive means which is responsive to a plurality of variable pressure factors.

The invention can be further briefly summarized as consisting in certain novel combinations and arrangements of parts hereinafter described and particularly set out in the appended claims.

In the accompanying sheets of drawings,

Fig. 1 is an elevational view, somewhat diagrammatic in character, showing fuel injection apparatus embodying the present invention.

Fig. 2 is a bottom plan view of the injector unit.

Fig. 3 is a vertical sectional view taken through the injector unit substantially as indicated by line 3-3 of Fig. 2.

Fig. 4 is a partial transverse sectional view taken on line 44 of Fig. 3 and which further illustrates one of the inlet valves and the valve actuating means.

Fig. 5 is a perspective view showing the valve actuating cam and the pressure responsive element in detached relation, and

Fig. 6 is a graphic illustration of the functional characteristics of the injector unit.

The improved fuel injection apparatus and the function thereof will now be described in greater detail. The embodiment of the improved apparatus here illustrated includes an injector unit III which serves an internal combustion engine ll and is operatively connected therewith. The engine I l is an internal combustion engine of either the Otto or Diesel type and, although the improved fuel injection apparatus is applicable to a single cylinder engine, it can advantageously be applied to a multiple cylinder engine and is therefore illustrated and described herein as being used with a multiple cylinder engine. The engine II is shown as having an air intake manifold I2 and a plurality of suitably located individual fuel injection nozzles I3 which serve the respective cylinders. The injection nozzles l3 could, of course, be located in the air intake passages of the respective cylinders if desired.

The fuel injection unit or distributor I0 is provided with a housing It in which the various parts are contained including a rotatable shaft l5 having lugs l6 enabling the same to be connected with the engine I I so as to be driven therefrom. The housing It is provided exteriorly thereof with a plurality of fuel delivery outlets 11, a fuel inlet connection l8 and a pressure connection IS. The fuel delivery outlets I! are connected with the respective injection nozzles l3 of the engine by the conduits Ila. The fuel inlet I8 is connected with an available source of liquid fuel, such' as a conventional fuel pump, by the conduit 20. The pressure connection I9 is in communication with the intake manifold I 2 of the engine through the conduit 2|.

As shown in the drawings and particularly in Fig. 3 thereof the housing It can be'of a sectional construction which includes a lower section Ila, an upper section Nb, and a cover section He. The shaft [5 is suitably journalled in the lower section Ma and projects therefrom so that it can be conveniently connected with the engine II to be driven therefrom when the unit I0 is engine. The lower housing section llais provided with a plurality of pump chambers 22 which are disposed in substantialhr circumferentially spaced relation around the shaft l5 and extend substantially radially with respect to the axis of shaft rotation. The pump chambers 22 are closed at their outer ends by suitable fittings 23 to which the fuel delivery conduits l'la are connected and which contain outwardly opening spring loaded check valves 24.

Pumping members which, in this instance, are in the form of plungers 25 are reciprocable in the pump chambers 22 and their inner ends are adapted to be engaged by an actuating cam 24 of appropriate shape and carried by the shaft l5. During rotation of the shaft l5 the cam 26 engages the plungers 25 in succession and imparts thereto an outward pumping stroke by which the liquid fuel is discharged from the pump chambers 22 past the check valves 24 and through .the delivery conduits [1a to the injector nozzles I chambers 22 the housing I4 is provided with fuel intake means which includes an annular intake space or gallery 3| formed in the upper portion of the housing section l4a. This intake space or gallery 3i is located at a point above the pump chambers 22 and extends around the axis of rotation of the shaft l5. The fuel intake means also includes intake passages 32 extending downwardly from the gallery 3| at spaced points therearound and which lead to the respective pump chambers 22 through a corresponding group of valve devices located between the gallery and the pump chambers and to which valve devices further reference will presently be made.

The fuel intake means preferably also includes a float chamber 34 formed in the upper housing section Nb and having a discharge passage 35 at its lower end which communicates with the gallery 3i. The float chamber 34' is supplied with fuel through the above-mentioned inlet connection l8. Th float chamber is also provided with an escape passage or vent 38 in the upper portion thereof and which leads directly to the atmosphere. A float 39 located in the float chamber is movable in response to variation in the fuel level and this movement of the float causes opening or closing of a suitable valve 40 which controls the vent passage 38.

In the fuel inlet means just described above it will be seen that since the gallery 3| and the float chamber 34 are located above the pump chambers 22, a solid body of liquid fuel will always be available in-the intake passages 32 and will be supplied by the latter to the pump chambers. Arnr air or vapor bubbles entrained in the liquid fuel will rise through the liquid standing in the float chamber 34 and will result in a collection of vapor in the upper portion of the float chamber. When the liquid level in the float chamber drops a predetermined amount the accompanying downward movement of the float 35 will open the valve 40 and permit the collected vapor 4 to escape to atmosphere through the vent 35. In addition to serving as a means for eliminating air or vapor from the fuel. the float chamber 34 also provides a temporary supply of fuel which will always be available for starting the engine I I even though the main fuel supplypump is not in operation or has not primed itself during the engine cranking operation. The matter of maintaining a solid body of liquid fuel in the supply passages 32 of the pump chambers 22 at all times is very important because it makes possible a desired rapid filling of these chambers to full capacity with a solid body fuel which is one of the necessary factors to be met if a uniform delivery of fuel is to be obtained from all of the pump chambers. It will be observed also that the inlet passages 32 and the inlet valves 42 for the respective pump chambers 22, as well as the float chamber 34 and the annular intake space If, all lie wholly above the pump chambers such that the flow of fuel downwardly into the pump chambers is always assisted by the force of gravity.

The fuel inlet passages 32 of the pump chambers 22 are controlled by inlet valves 42 which are also disposed in circumferentially spaced relation in a group around the axis of the shaft l5 and are, at times, hereinafter referred to as control valves because they control the pumping action produced by the plungers 25. The valves 42 are preferably in the form of piston valves extending substantially radially of the shaft I5 and transversely to the inlet passages 32. The valves 42 are slidable in valve sleeves 43 which are suitably mounted in the housing section 14a and have ports 43a and 431) which are connected respectively with the gallery 3! and the inlet passages 32.

The inlet or control valves 42 are actuated in succession by means of a cam 44 carried by the shaft l5 and which will be further described hereinafter. The inner ends of the valves 42 engage the cam 44 and during rotation of the shaft l5 the cam moves the valves outwardly to cause successive closing of the inlet passages 32 leading to the respective pump chambers 22. The valves 42 are held against the cam 44 by compression springs 45 which also act to shift the valves in an inward direction to cause opening of the inlet passages 32. The shape or contour of the cam 44 is a important factor and, as shown in Fig. i'of the drawings and hereinafter described, is such that the control valves 42 will remain open at all times during the cycle of operation except for that predetermined portion of the pumping stroke of the plungers 25 which corresponds with the desired fuel injection period during which fuel is delivered to the nozzles l3. By having the valves 42 remain open in this manner the solid body of liquid fuel available in the gallery 3| will flow freely downwardly through the inlet passages 32 into the pump chambers 22 and the pressure of the fuel in the pump chambers will be substantially the same as the pressure in the gallery at all times except during that portion of the working stroke of the pump plungers when the inlet valves 42 are closed.

It will also be seen from the construction above described for the inlet or control valves 42 that the parts 43a and 43b provide an inlet passage of a size such that the fuel will flow freely downwardly to the pump chambers 22 and will be assisted by the force of gravity. Moreover, it will be seen that the valves 42 will cooperate with these ports in a manner to cause a quick opening and closing of the assage with very little metering effect on the fuel at this point. By employing the piston valves 42 in the arrangement above described it will also be seen that the pressure developed in the pumping chambers 22 will act against the sides of the piston valves and these valves will be subjected to very little endwise thrust by the pressure of the fuel and hence the load imposed on the cam 44 by these valves will be relatively light. v

The valve actuating cam 44 has an axial sleeve portion 45a by which it is slidably mounted on the shaft I5. The cam is connected for rotation with the shaft as by means of the key 45. Movement of the cam in an axial direction relative to the shaft I causes different portions of the cam contour to become effective in actuating the control valves 42 and in this way the actuation of the control valves is varied with respect to the cycle of the engine II and in relation to the fuel requirements of the engine. A compression spring 41 disposed in the hollow cam 44 normally tends to shift the cam in a direction which will vary the opening movement of the valves 42 so as to retard the beginning of the fuel injection period.

The cam 44 is shifted in theopposite direction, that is in a direction to advance the beginning of the injection period, by a thrust applying member 49 which is movable in the direction of the axis of the shaft I5 and is slidably mounted in the housing section |4b so as to extend into a pressure chamber 50 contained in the latter. The chamber 50 is connected with the intake manifold I2 of the engine H by the above mentioned conduit 2 I. A sealed flexible hollow element 5| is located in the pressure chamber 50 and has its fixed upper end 5Ia connected with the cover section I40 and its movable lower end 5|b in bearing engagement with the thrust transmitting member 49.

The hollow element 5| is expansible and contractible in response to pressure variations which occur in the chamber 50 and in the intake manifold I2 with which this pressure chamber is connected. The hollow element 5| contains air or other gas of a desired initial density or pressure and when the pressure in the chamber 50 decreases, as would occur when the throttle of the engine II is suddenly closed, the element 5| will expand and will transmit thrust to the cam 44 through the slidable element 49. The cam 44 will be thereby shifted axially in a direction to render the cam contour effective for keeping the control valves 42 open during a greater portion of the angular movement of the shaft I5 and hence decreasing the amount of fuel which will be delivered from the pump chambers 22 to the injector nozzles I3. Conversely, when the pressure in the chamber 50 increases or is restored, as would be the case during the operation of the engine with full or substantially full throttle opening, the element 5| will be contracted or compressed and the spring 41 will shift the cam 44 in the opposite direction to cause an earlier closing of the control valves 42 and the consequent delivery of an increased amount of fuel to the engine.

The end member 5|a of the expansible hollow element 5| may have a threaded stem portion 5Ic by which the hollow element is mounted on the cover Me of the housing. The stem 5|c has a passage 52 therein through which the air or other gas is introduced into the hollow element acsaaov it provide the desired initial gas density and pressure therein. when this desired initial zas density and pressure have been established in the hollow element 5| the outer end of the passage 53 is permanently sealed. The threaded stem 5 lo and the lock nut 54 thereon provide an adjusting means by which the action of the expansible hollow element 5| andthe axially shiftable cam 44 can be adJusted or calibrated.

Fig. 6 of the drawings illustrates graphically the operating characteristics of the injector unit In by analyzing the movement of one of the pump plungers 25 and the movement of the associated inlet or control valve 42 as produced by the variable contour of the cam 44. In this graphic illustration the curve 56 portrays the movement of the pump plunger in relation to the angular displacement of the shaft I5. The scale 51 represents plunger movement in hundredths of an inch and the scale 58 represents degrees of angular movement of the shaft I5.

The curve 59 portrays the movement of the control valve 42 and the scale 60 represents the movement of this valve in hundredths of an inch.

The line 8| is the line of zero control valve movement and represents, the closed position of the valve 42. The valve movement represented by the distance or dimension 62 represents the open condition of the valve during which free communication exists between the pump chamber 22 and the gallery 3 I. The distance or dimension 63 represents the closed condition of the valve during which fuel is being delivered from the pumping chamber 22 and injection is taking place through the nozzle I3. The curves 56, 61, 58 and 59 represent the valve movement corresponding with different effective contours of the cam 44 depending upon its position of axial movement relative to the shaft I5. The curve 59 represents the valve movement produced by the contour which is effective at full capacity operation of the injector unit. Curves 56, 61, 58 and 69 represent the valve movement for other efiective contours of the cam 44 corresponding with different axial stations to which the cam is shifted in response to diiferent operating conditions of the engine as represented by variations in the pressure of the intake manifold I3.

The broken line curve III of Fig. 6represents the control valve movement for the effective contour of the cam 44 when the cam is at a position or station corresponding with an idling condition of the engine I I. The intersection of the zero line 6| with the cam contour curve 59 substantially at the 70 shaft displacement station represents the start ofthe fuel injection period and is substantially the position at which the control valve 42 is shown in Figs. 4 and 5. The portion of the pump plunger curve 56 which is represented by the distance or dimension 12 shows the effective movement or travel of the pump plunger 25 at full capacity operation of the injector unit. Similarly, the distance or dimension I3 represents the is in its open position. A relatively smaller portion of the periphery has an elevated cam proiection b thereon whose angular extent at its widest part is represented by the portion of the Scale-i8 which is occupied by the curve 59.

The projection b of the cam varies in height and width and both of these factors decrease progressively during axial travel along the cam surface in a direction toward the flexible hollow body ii. The projection I: therefore is of a somewhat triangular shape as shown in Fig.

in which the junction area between the projection and the main periphery or body portion a is represented by the line c which is substantially straight but is inclined relative to the longitudinal axis of the cam. The junction area between the main periphery and the opposite edge of the projection b is represented by the line d which is also substantially straight but extends axially of the cam. The main periphery of the cam is cylindrical in shape adjacent the junction line c but is somewhat'fiattened adjacent the junction line at as represented by the. section or area He, the latter having an angular extent of approximately 40.

During rotation of the cam 44 in the direction of the arrow the projection 44b will approach the control valve 42 and at the point of the cycle where the valve passes over the line He the valve closes the inlet passage 32 and the fuel injection period begins. This is also represented by the position in which the valve is shown in the graph of Fig. 6 in relation to the curve 59 and the zero l ne 6|. Because of the relative inclination of the line 440 it will be seen that this closing point for the valve will occur at different angular points of the engine cycle according to the different axial stations to which the cam 44 is shifted. This is represented in Fig. 6 by the different points at which the curves 66, i1, 68 and 69 intersect the zero line 6|.

During the time that the control valve 42 rides over the projection b the valve remains closed and this portion of the cycle corresponds with the fuel injection period and is represented by the portions of the curves 59, 66, 61, 68 and 69 which lie. above the zero line 5| When the valve passes over the line d of 'the cam it begins to open and this corresponds with the end of the injection period. Since the line 44d extends in a straight axial direction on the cam 44 it will be apparent that the opening pointfor all axial stations of the cam will be at the same point of the engine cycle. This is illustrated in the graph of Fig. 6 by the fact thatall of the curves 59, 66, 61, 68 and 69 cross the zero line 6| at the same point which is designated 14. For the portion of the engine cycle during which the valve passes over the section e and the cylindrical main portion a of the cam periphery,

. the valve is open and this is represented in Fig.

requirement decreases, the beginning of injection will occur laterin the cycle but the end of the injection period will remain substant'ally constant. Ithas been found that this arrangement and functional performance compfies best with the requirements of most engines but the contour 8 of the cam can be changed as desired to provide for other conditions which may be found more desirable in regard to the length of the injection period and in regard to the beginning or end of the injection period.

Although the foregoing analysis is carried through by referring to only one control or inlet valve 42 and one pum'p plunger 26, it will be understood that the same analysis applies to allof the control valves and pump plungers of the annular group. Moreover, since all of the valves are actuated in exactly the same manner and to exactly the same extent for a given cam station it is possible to obtain an extreme uniformity of fuel delivery for all of the engine cylinders. It is also important to note from the foregoing description and analysis that each inlet or control valve 42 will be positively held open during the entire intake stroke or filling period for its pump chamber, and that this will eliminate vapor lock and will result in the pump chambers being filled with a solid body of fuel before each pumping stroke. It should also be pointed out that the contour and angular position of the valve actuating cam 44 in reation to the plunger actuating cam 26 is such that the inlet or control valves 42 will not only be held open during the entire intake period but also for a portion of the pumping stroke of the plungers 25. This further insures the instantaneous delivery of a solid body of liquid fuel from each pump chamber upon the closing of its control valve.

It has been pointed out above how the sealed expansible and contractible element 5| causes shifting of the cam 44 in response to variations in the pressure in the intage manifold I! of the engine. This hollow element also causes shifting of the cam 44 in the same manner in response to changes in operating temperature and changes in barometric pressure of the atmosphere. The movement imparted to the cam 44 by the hollow member 6| will be a combined or resultant movement in which the pressure effects of the intake manifold, temperature variations and barometric pressure var'ations are factors.

The movement produced by the hollow member 5! in response to temperature changes enables this member to compensate for temperature changes encountered from seasonal changes or from variations in altitude. As mentioned above, the hollow element 5! can be sealed with a desired air or gas density therein and when a relatively high density is provided this hollow member will produce an increased cam movement for a given change in temperature. Likewise, the air or gas density provided in the hollow member 5| can be selected with reference to a given barometric pressure which enables the injection apparatus I!) to be set or calibrated for a desired performance with respect to barometric pressure or operating altitude.

It should also be pointed out that the spring 41 for the cam M is selected in relation to the cam contour and the action of the hollow element 5| such that any desiredrelationship between fuel flow and engine manifold pressure can be obtained over the entire range of engine performance. In the operation of the injector unit 10 the amount of fuel delivered from the pump chambers 22 will be directly proportional to a change in engine speed for any given manifold pressure. Furthermore, since the intake air will be directly proportional to any change in speed of the engine, the fuel, air ratio and/or mixture strength. will remain constant over a wide range of engine Although the fuel injection apparatus of the present invention has been illustrated and described herein in considerable detail, it will be understood, of course, that the invention is not to be regarded as limited correspondingly but includes all changes and modifications coming within the scope of the appended claims.

Having thus described my invention, I claim:

1. In fuel supply apparatus for engines, a housing, a shaft rotatable in said housing, a plurality of pump chambers in said housing and disposed around said shaft and provided with fuel delivery outlets, pumping members in said chambers driven from said shaft and having reciprocable intake and discharge strokes, means defining in said housing an inlet space located above said chambers and extending around the axis of said shaft and adapted to contain a solid body of liquid fuel and including inlet passages extending downwardly to the respective pump chambers, valves disposed around said shaft and controlling the respective inlet passages, and means for causing positive actuation of said valves from said shaft such that each valve is held open during the entire intake stroke of its associated pumping members, said inlet space and inlet passages being located wholly above said pump chambers such that the flow of liquid fuel into said pump chambers is assisted by the force of gravity.

2. In fuel supply apparatus for engines, a housing, a shaft rotatable in said housing, a plurality of pump chambers in said housing and disposed around said shaft and provided with fuel delivery outlets, pumping members in said chambers driven from said shaft and having reciprocable intake and discharge strokes, means defining in said housing an inlet space located above said chambers and extending around the axis of said shaft and adapted to contain a solid body of liquid fuel and including inlet passages extending downwardly to the respective pump chambers, piston valves disposed around said shaft and extending across the respective inlet passages for controlling the latter, means for causing positive actuation of said piston valves from said shaft such that each valve is held open during the entire intake stroke of its associated pumping member, said inlet space also including a float chamber having a gas escape passage in the upper portion thereof and a liquid feed passage at the lower end thereof leading into said inlet space, and means controlling said escape passage including a float valve and a float movable in said float chamber for actuating said float valve, said inlet space including said float chamber and said inlet passages being located wholly above said pump chambers such that the flow of liquid fuel into said pump chambers is assisted by the force of gravity.

3. A fuel supply apparatus for engines comprising, a housing having therein a pump chamber stroke corresponding with the desired fuel delivery period, said inlet passage being located wholly above said pump chamber such that the flow of fuel into said pump chamber is assisted by the force of gravity.

4. A fuel supply apparatus comprising, a housing having therein a pump chamber provided with inlet and delivery passages, a shaft rotatable in said housing, a pumping member in said chamber driven from said shaft and having reciprocable intake and discharge strokes, a valve controlling said inlet passage, cam means for causing positive actuation of said valve from said shaft such that the valve is held open during the entire intake stroke and a portion of the discharge stroke of said pumping member and is held closed durin the portion of the discharge stroke corresponding with the desired fuel delivery period, said cam means including a cam of a variable contour and shiftable along the axis of said shaft for varying said fuel delivery period, an expansible and contractible fluid pressure containing bulb adapted to cause such axial shifting of said cam in one direction, and spring means adapted to cause axial shifting of said cam in the opposite direction.

5. A fuel supply apparatus for engines comprising, a housing having therein a pump chamber provided with inlet and delivery passages. a shaft rotatable in said housing, a pumping member in said chamber driven from said shaft and having reciprocable intake and discharge strokes, a valve controlling said inlet passage, cam means for causing positive actuation of said valve from said shaft such that the valve is held open during the entire intake stroke and a portion of the discharge stroke of said pumping member and is held closed during the portion of the discharge stroke correspondingwith the desired fuel delivery period, said cam means including a cam of a variable contour and shiftable along the axis of said shaft for varying said fuel delivery period, said housing also having a pressure chamber therein adjacent said shaft, and an expansible and contractible hollow element in said pressure chamber and adapted to cause such axial shifting of said cam in response to pressure variations in said pressure chamber.

6. A fuel supply apparatus for engines comprising, a housing having therein a pump chamber provided with inlet and delivery passages, a shaft rotatable in said housing, a pumping member in said chamber driven from said shaft and having reciprocable intake and discharge strokes, a valve controlling said inlet passage, cam means for causing positive actuation of said valve from said shaft such that the valve is held open during the entire intake stroke and a portion of the discharge stroke of said pumping member and is held closed during the portion of the discharge stroke corresponding with the desired fuel delivery period, said cam means including a cam of a variable contour and shiftable along the axis of said shaft for varying said fuel delivery period, said housing also having a pressure chamber therein adjacent said shaft, and an expansible and contractible hollow element in said pressure chamber and adapted to cause such axial shifting of said cam in response to pressure variations in said pressure chamber, said hollow element having a predetermined gas density initially sealed therein.

7. A fuel supply apparatus comprising, a housing having therein a pump chamber provided with a fuel delivery outlet, a shaft rotatable in said housing and adapted to be driven, a plunger reclprocable in said pump chamber and actuated from said shaft with a substantially constant intake stroke and a substantially constant pumping strokefor discharging fuel through said delivery outlet, means defining an inlet space in said housing including an inlet passage leading to said pump chamber, a valve controlling said inlet passage, and a cam driven by said shaft and cooperating with said valve to cause a positive closing thereof, said plunger being efiective to produce a fuel delivery period while said valve is closed, said cam being adapted for limited shifting relative to said shaft and having a contour such that said valve is held open during the entire intake stroke of said plunger and such that the beginning of the fuel delivery period will be variable but the end of the delivery period will remain substantially constant for the different positions to which said cam is shifted.

8. A fuel supply apparatus comprising, a housing having therein a pump chamber provided with a fuel delivery outlet, a shaft rotatable in said housing and adapted to be driven, a plunger reciprocable in said pump chamber and actuated from said shaft with a substantially constant intake stroke and a substantially constant pumping stroke for discharging fuel through said delivery outlet, means deflning an inlet space in said housing including an inlet passage leading to said pump chamber, a valve controlling said inlet passage, a cam driven by said shaft and cooperating with said valve to cause a positive closing thereof, said plunger being effective to produce a fuel delivery period while said valve is closed, said cam being adapted for limited shiftto the respective pump chambers, piston valves disposed around said shaft and extending across the respective inlet passages for controlling the latter, a cam on said shaft for causing a positive actuation of said piston valves so as to close said inlet passages in succession, said plungers ing relative to said shaft and having a contour such that said valve is held open during the entire intake stroke of said plunger and such that the beginning of the fuel delivery period will be variable but the end of the delivery period will remain substantially constant for the different positions to which said cam is shifted and an expansible and contractible fluid pressure containing bulb means for causing such relative shifting of said cam.

9. In fuel supply apparatus, a housing, a shaft rotatable in said housing and adapted to be driven, a plurality of pump chambers in said housing and disposed around said shaft, said pump chambers having fuel delivery outlets, plungers reciprocable in said pump chambers and driven from said shaft so as to have substantially constant intake and pum ing strokes and to be moved through their pum ing strokes in succession, means defining in said housing a fuel inlet space including inlet passages leading to the respective pump chambers. valves disposed around said shaft and controlling the respective inlet passages, a cam on said shaft for causing a positive actuation of said valves so as to close said inlet passages in succession, said plungers being effective to produce fuel delivery periods in succession as said inlet passages are close by said valves, said cam being ada ted for limited shifting relative to said shaft and having a contour such that each valve will be held open during the entire intake stroke of its associated plunger and such that the be inning of said fuel delivery periods will be variable but the end of said fuel delivery periods will be substantially constant for the d fferent pos tions to which said cam is shifted, and an exnansible and contractible fluid pressure containing bulb effective on being effective to produce fuel delivery periods in succession as said inlet passages are closed by said valves, said housing having a chamber therein adjacent said cam and a connection for supplying fluid to said chamber, said cam being adapted for limited shifting relative to said shaft and having a contour such that each valve will be held open during the entire intake stroke of its associated plunger and such that the beginning of said fuel delivery periods will be variable but the end of said fuel delivery periods will be substantially constant for the different positions to which said cam is shifted, and an expansible and contractible fluid pressure containing bulb located in said chamber and effective on said cam for causing such relative shifting thereof.

llJIn fuel supply apparatus, a housing, a shaft rotatable in said housing and adapted to be driven, a plurality of pump chambers in said housing and disposed around said shaft, said pump chambers having fuel delivery outlets, plungers reciprocable in said pump chambers and driven from said shaft so as to have substantially constant intake and pumping strokes and to be moved through their pumping strokes in succession, means defining in said housing a fuel inlet space including inlet passages leading to the respective pump chambers, valves disposed around said shaft and controlling the respective inlet passages, a cam on said shaft for causing a positive actuation of said valves so as to close said inlet passages in succession, said cam being of variable contour and shiftable relative to said shaft for varying the actuation of said valves, and fluid pressure responsive means for causing such shifting of said cam, said plungers being effective to produce fuel delivery periods in succession as said inlet passages are closed by said valves and said cam having a contour such that each valve will be held open during the entire intake stroke of its associated plunger and such that the beginning of said fuel delivery periods will be variable but the end of said fuel delivery periods will be substantially constant for the different positions to which said cam is shifted, said fuel inlet space and said inlet passages being located wholly above said pump chambers such that the flow of fuel into said pump chambers is assisted by the force of gravity.

12. In fuel supply apparatus, a housing, a shaft rotatable in said housing and adaped to be driven, a plurality of pump chambers in said housing and disposed around said shaft, said pump chambers having fuel delivery outlets, plungers reciprocable in said pump chambers and said cam for causing such relative shining driven from said shaft so as to be moved through thereof.

their pumping strokes in succession, means defining in said housing a fuel inlet space extending around the axis of said shaft above the pump chambers and adapted to contain a solid body of liquid fuel and including inlet passages extending downwardly to the respective pump chambers, said inlet space also including a float chamber having an escape passage in the upper portion thereof, means controlling said escape passage including a float movable in said float chamber, piston valves disposed around said shaft and extending across the respective inlet passages for controlling the latter, a cam on said shaft for actuating said valves so as to close said inlet passages in succession, said cam having a variable contour and being shiftable relative to said shaft for varying the actuation of said valves, said housing also having a pressure chamber therein adjacent said cam, means for supplying pressure fluid of variable pressure value to said pressure chamber, and an expansible and contractible hollow element in said pressure chamber and adapted to cause such shifting of said cam in response to pressure variations in said pressure chamber, said plungers being effective to produce fuel delivery periods in succession as said inlet passages are closed by said valves.

13. In fuel supply apparatus, a housing, a shaft rotatable in said housing and adapted to be driven, a plurality of pump chambers in said housing and disposed in a group around said shaft, said pump chambers having fuel delivery outlets, plungers reciprocable in said pump chambers and driven from said shaft so as to have substantially constant intake and pumping strokes and to be moved through their pumping strokes in succession, means defining in said housing a fuel inlet space extending around said shaft above the pump chambers and adapted to contain liquid fuel and including inlet passages extending downwardly to the respective pump chambers, piston valves disposed in a group around said shaft and extending across the respective inlet passages for controlling the latter, a cam on said shaft for causing a positive actuation of said valves so as to close said inlet passages in succession, said cam having a variable contour and being shiftable relative to said shaft for varying the actuation of said valves, said housing also having a pressure chamber therein adjacent said cam, means for supplying pressure fluid of variable pressure value to said pressure chamber. and means responsive to pressure variations causing such shifting of said cam, said plunger-s being effective to produce fuel delivery periods in succession as said inlet passages are closed by said valves, the contour of said cam being such that each valve will be held open during the entire intake stroke of its associated plunger and such that the beginning of said fuel delivery riods will be variable but the end of said fuel delivery periods will be substantially constant for the different positions to which said cam is shifted.

14. In fuel supply apparatus, a housing, a, shaft rotatable in said housing and adapted to be driven, a plurality of pump chambers in said housing and disposed in a group around said shaft, said pump chambers having fuel delivery outlets, plungers reciprocable in said pump chambers and driven from said shaft so as to be moved through their pumping strokes in succession, means defining in said housing a fuel inlet space extending around said shaft above the pump chambers and adapted to contain liquid fuel and including inlet passages extending downwardly to the respective pump chambers, piston valves disposed in a group around said shaft and extending across the respective inlet passages for controlling the latter, a cam on said shaft for actuating said valves so as to close said inlet passages in succession, said cam having a variable contour and being shiftable relative to said shaft for varying the actuation of said valves, said housing also having a pressure chamber therein adjacent said cam, means for supplying pressure fluid of variable pressure value to said pressure chamber, and an expansible and contractible hollow element in said pressure chamber and adapted to cause such shifting of said cam in response to pressure variations in said pressure chamber, said plungers being effective to produce fuel delivery periods in succession as said inlet passages are closed by said valves.

JOHN F. CAMPBELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,080,216 Hoadley Dec. 2, 1913 1,137,877 Manly et al May 4, 1915 1,149,728 Ciario Aug. 10, 1915 1,239,060 Sundh Sept. 4, 1917 1,597,787 Hausser et a1 Aug. 31, 1928 1,653,885 VanGuilder Dec. 27, 1927 1,902,930 Zubaty Mar. 28, 1933 1,962,551 Carter et al June 12, 1934 2,058,591 Kammer Oct. 27, 1936 2,107,079 Mentele Feb. 1, 1938 2,174,898 Scott Oct. 3, 1939 2,192,660 Johnson Mar. 5, 1940

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