US2291939A - Pump and fuel injection control device - Google Patents

Description

7 Au 4, 1942. G.'AMERY 2,291,939

PUMP AND FUEL INJECTION CONTROL DEVICE Filed Aug. .15, 1933 s sheets-sheet 1 1-77U67ZZL0 7."

Aug. 4,1942. G. AME RYI I 2,

PUMP AND FUEL INJECTION CONTROL DEVICE Filed Aug. 15,. 1938. 5 Sheets-Sheet 2 Aug; 4, 1942. s. AMERY 2,291,939

PUMP AND FUEL INJECTION CONTROL DEVICE Filed Aug; 15', 1938 5 Sheets-Sheets l l Q sq Q,

I l I r Aug-4,1942 G. AME? T 2,291,939

PUMP AND FUEL INJECTION CONTROL DEVICE "Filed Aug. 15, 1938 ,5 hosts-Sheet 4' Aug. 4, 1942. G. A 2,291,939

f UMP FUEL INJEC'iION CONTROL DEVICE Filed Aug. 15, 19:8 7 s Sheets-Sheet 5 v INVENTOR 19% 6,17% 7 MM K 24. SfiMwMM Patented Aug. 4, 1942 George Amery, London, England 7 Application August 15, 1938, Serial No. 225,025

In Great Britain August 25, 1937 10 Claims. (01. 123-139) driving member and its piston are co-axial with This invention comprises improvements in or relating to fuel-injection controlling devices for internal-combustion engines.

The present invention relates to a fuel-injection apparatus which in the construction described embodies in a single unit a fuel pump, governor mechanism for controlling the fuel pressure and distributing means for determining the delivery of fuel oil to injector devices upon the engine cylinders.

The present invention comprises (in fuel-injection apparatus for an intemal-combustion compression-ignition engine comprisinga pump 7 for pumping fuel oil under pressure and a distributor for distributing said fuel oil to injector pressure of the fuel oil increases with increasin engine speed) the provision of automatic means operated by the fuel-oil pressure for advancing the timing of the distributor under increased fuel-oil pressure. v

The distributor may comprise mechanically actuated distributor valves, a rotatable axiallysiidable intermediate driving member through which the means for actuating the valves is driven, and a piston subject to the pressure of the fuel oil, which piston acts to determine the posi-v tion of the intermediate driving member, the construction being such that the axial sliding movement of the said driving member serves'to advance or retard the position of the actuating means.

cam.

' devices, the arrangement being such" that the the distributor-cam.

A fuel pump may be incorporated in the unit and connected directly to the control chamber and distributor to deliver fuel oil under pressur thereto. r

The invention further relates to features of the pump which are not in themselves limited to their use in a fuel pump as herein described. To this end the invention-comprises in a pump the provision ofan inlet passage to the pump, a filter spanning said inlet passage and means whereby part of the liquid drawn into said inlet passage through the filter is displaced backwardly through the filter at each working stroke of the pump for the purpose of keeping the filter clean.

While it would be possible to arrange for the pump plunger itself to effect the said partial return displacement of the fluid being pumped The actuating means is preferably a A control chamber maybe provided in which the piston for advancing and retarding the distributor operates, together with a relief-valve,-

for controlling the fuel pressure, which is located in the wall of the control-chamber.

The relief-valve maybe governed by a centifugal governor arranged in one unit with the distributor and the driving means therefor. The governor and the distributor may be interconnected by a lay shaft geared to both of them.v

Moreover, the axially-slidable intermediate driving member for advancing and retarding the distributor may be constituted by one of the gears in thetrain between the governor and the cam, which gear has helical driving teeth so that the teeth alter the timing upon the aforesaid axial movement.

In a preferred arrangement the governor, the control chamber and the distributor-cam are coaxial with one another, the lay shaft is parallel to them and the"axially-slidable intermediate through the filter by holding up the closing of the, inlet port of the pumpduring a part of the return stroke of the pump plunger, it is-preferable to use separate means for producing the retum flow through the filter. To this end, in one con.-

struction of fuel pump according to the invention the pump comprises in combination a pump plunger, an inlet passage thereto, a filter spanning said inlet passage and a plunger operating ram, of greater diameter than the pump plunger, working in said inlet passage, the arrangement being such that the plungeroperating ram displaces a portion of the fuel in the inlet passage back through the filter during the delivery strolre of the pump plunger.

The following is a description by way of example-of one form of fuel-injection apparatus in accordance with the. inventiom with reference to the accompanying drawings, in which:

Figure 1 is a longitudinal section through a fuel supply and distribution unit:

- Figure 2 is a transverse section upon the line 2-2 of Figure 1, looking'in the direction of the arrows;

Figure 3 is a detail transverse section upon the line {-3 of Figure 1, looking in the direction of the arrows;

' Figure 4 is another longitudinal section in a different plane from Figure 1 as indicated by the line 4-4 in Figurezz Figure 5 is an end view of the .distributorwith the central portion broken away to show the lnternal construction;

Figure 6 is a diagram Figure 7 is a section of the pipe connections: through one of the distributor valves in a plan at right angles to that of Figure 5; and

Figure 8 is a section through one of the injector nozzles. v

Like reference characters indicate like-parts throughout the drawings.

Referring to Figure 1, the apparatus comprises a casing II to which is screwed at one end a cap l2 which forms a housing for a ball bearing l3 supporting a driving shaft |4. At the otherend of the casing there is secured by means of screws IS a distributor casing l5.

The driving shaft l4 has.a head 25 which is screwed on to a rotatable casing 2| supported at the end remote from the driving shaft H in a ball bearing 22 in the casing Within the casing 2| and rotating therewith are centrifugal governor weights 23 which act on a relief-valve 24 through interposed springs 25, 25 in the same vmanner as the governor which is more fully described in prior United States patent application Serial No. 117,964, filed December 28, 1936., The head of the relief-valve 22 is: subjected to oil pressure in a control-chamber 21. formed in a diaphragm 28 which is eo-axial with the govout gear teeth 35 for driving a lay shaft 31 and there is mounted a pump-operating cam 35.

' The lay shaft 31 is seen in Figure 4 and its relationship to the governor casing 2| is shown in Figure 2.

Referring to Figure 4, the lay shaft, 31 is splined within a sleeve 35 which is mounted on ball bearings |39, |45 in the casing The sleeve 38 carries gear teeth 39 which mesh with the gear teeth 35 on the governor casing 2| and thus the sleeve is driven by the governor casing and the lay shaft 31 by the splines on the sleeve. The sleeve 35 also carries a second pumpoperating cam 45 and as the sleeve necessarily always rotates with the lay shaft 31, it may be regarded from the point of view of operating the pump as part of the lay shaft.

Referring to Figure 2, the two pump-operating cams 35, 45 each act upon a plunger-operating ram4l, 42 respectively. The rams are made a close fit in, guide-bores in the casing II and bear upon flanges 43, 44 carried by plungers 45, 45. Two return springs 41 serve to press the plungers and the ramsdownwardly and maintain contact between the rams and the cams 55, 45.

The plungers 45, 45 work in pump barrels 45, and the pump barrels serve to close the upper ends of inlet chambers 55, 5| which surroundthe barrels 48, 49 and the upper ends of the rams 4|, 42. It will be observed that the plungeroperating rams 4| 42 are larger in diameter than -t-he pump plungers 45, 45. The pump barrels 45.

49 are held down on the casing II by a delivery box 52 which is secured in place by set-screws 53. The delivery box 52 contains a pump delivery chamber 54 into which both the pump plungers 45, 45 deliver fuel oil under pressure and from which the oil is taken by various pipe connections hereinafter referred to. In the upper end of each pump barrel is a delivery valve 55 held on its seat by a spring 55.

In Figures 1 and 4 can be seen inlet ports 51, 55 to the pump barrels 45, 49. These ports are uncovered when the pump plungers are in their lowermost position, so as to admit fuel oil to the interior of the pump barrels and are closed by the plungers during their ascent under the influence of the cams 35, 45. The inlet passage for fuel oil to the fuel pump is constituted in part by two filter chambers 55, 5| (Figures 1, 3 and 4) which .are connected to the inlet chambers 5| and 55 respectively by ports 59. Each of the filter chambers is spanned by a filter element 52 which is set at an inclination to the horizontal such that the inlet for 'fuel to the top of the filter chamber, 55 or 5| as the case may be, is above the filter element 52, while the port 59 is below it. Fuel enters through an inlet pipe 53 which has a divided delivery opening 54 into the upper portion of the two fllter chambers (Figure 3). Drain plugs 55 are provided for the removal of any accumulated dirt and the filter-elements themselves can be removed endwise from the chambers upon the removal of end plates 55, 51 (Figure 3) Before describing the rest of the apparatus it will be convenient to refer to the operation of the pump. It will be observed from Figure 2 that the shape of the cams 35, 45 is such that the delivery stroke takes longer than the suction stroke and by properly shaping the cams it is possible for an almost uniform flow of oil to be secured without any dead point," as the deliveries of the two barrels overlap.

Owing to the fact that the plunger-operating rams 4|, 42 are larger in diameter than the pump plungers 45, 45 and work in the closed inlet chambers 55, 5|, a larger quantity of fuel rams 4|, 42 displace this excess fuel oil backwards through the filters 52 and this temporary backward surge of oil tends to displace any dirt which may have collected on the surface of they filter and to allow it to fall into the lower portion of the space abovethe filter elements, thus preventing the filter elements from becoming clogged. Inspection on removal 'of the screws 55 can readily beefifected to ascertain if any material quantity of sediment has collected, and if so it can either be-washed out through the apertures for the screws, or if necessary, the filter elements can be removed afer taking off the end plates 55, 51.

The lay shaft 31 is employed for operating the distributor 5 andto this end it is splined within a gear wheel 15 supported on a ball hearing I15 (Figure 4) which meshes with a gear wheel 1| (Figure 1) which drives the distributor cam 12 through an intermediate shaft 13. The gear wheels 15, 1| are made with helical teeth and the gear wheel 1| is axially movable so that the timing of the distributor-cam 12 can be advanced or retarded by axial movement of the gear wheel 1|.

The lay shaft 31 is pressed yieldingly to the left; as viewed in Figure 4, by a spring 5 and is capable of hand-adjustment against the action of the spring by a screwed spindle passing througlithe end cap I 2 and secured by a lock nut H2. The spindle III is provided with a square 3 so that it can be set by a key. The splined connection between the lay'shaft 31 and the gear wheel 15 is made with helical splines and therefore endwise movement of the lay shaft 31 will advance or retard the gear wheel I4 relatively to the lay shaft. This provides a limited hand-adjustment for the'distributor timing.

Referring to' Figure 1, this shows the gear wheel II at the extreme left-hand end of its travel where it is held by a spring 14 bearing a ball thrust race IS. The gear wheel II is supported so as to be concentric with the distributor and governor axis by means of an internal ball race I9 carried on a cylindrical stem II projecting from the diaphragm 28.- The gear wheel II is made a sliding fit on the outside of this ball race. The stem [1 is bored out to constitute a cylinder within which works a control pisto'n I8 and the cylinder opens directly out of the control chamber 21. The pressure of the fuel oil therefore acts on the piston 18 and if the fuel pressure is suflicient the gear wheel II will be forced to the right against the action of the spring I4. It will'be recollected thatthe action of the governor weights 23 is to cause the fuel pressure to increase as the engine speed increases, as more fully described in the aforesaid United States patent application Serial No. 117,964; filed,

December 28, 1936. Consequently, if the strength of the spring I4 is properly proportioned relatively to the fuel pressure and the size of the piston I8, the gear wheel II will occupy various positions under the differing fuel pressures at various engine speeds and the distributor-cam I2 will be advanced as the engine speed increases, owing to the twisting movement imparted to the gear wheel II, when axial movement occurs, by the helicalteeth with which it is provided. The relief valve 24, as more fully set forth in the said application Serial No. 117,964, ensures a high injection pressure for the first few strokes when starting. This has the effect of advancing the ignition in the present construction, but as it only applies to the first. few engine strokes until the engine reaches idling speed, it is inmany cases immaterial, ifthe adjusting screw III is not set too far in'the direction of advance. If the engine is such as to require'an ignition timing which would be too advanced for easy starting in this way, a hand adjustment lever may be provided for temporarily retarding the ignition when starting. This can operate, by suitable controls, the screw III which could be provided with a quick thread for the purpose.

The gear wheel II is splined to the intermediate theinfiuence of the piston I8 are transmitted o the shaft It and the shaft I3 has alongitudinal slot I9 which passes right through the shaft from side to side and is-traversed by a key on the cam I2 so that angular movements of the shaft 13 are transmitted to the cam I2. The shaft I3 is supported in the distributor casing I5 byball bearings 80, I80. It will therefore be seen that the gear wheel II constitutes an axially-slidable intermediate driving member through which the cam I2 is driven and the position of which is determined by the piston I8.

The shaft I3 can be seen in Figure 5 within the cam I2 and this figure shows the position of the key 8| within the cam which traverses the slot I9 in the-shaft I9. A spring'82 (Figure 1) within the shaft I3 bears on the transverse key 8| and tends to force the cam I2 as far as possible to the right, as viewed in Figure l. A

' plunger 83 which projects beyond the end of the distributor casing I0 and is-co-axial with the shaft I3, enters the casing I! through a'seal I13 and is extended into the end of theshaft I3 and secured to the transverse key 8|. By pressure upon the plunger 03 it is therefore possible to move the distributor-cam axially along the shaft I3, the cam'being returned, if the pressure is relieved, by the spring 82. The cam isformed so that it can vary the period of injection of fuel oil and the plunger 83 is therefore connected to a hand-control, for regulating the power delivered by the engine with which the distributor is intended to be employed.

As shown in Figure 5 the distributor-cam I2 actuates a number of 'plungers 90 disposed radially around it, which plungers operate pistonvalves 9| and are forced radially inwards so that the plungers bear against the cam-by means of return springs 92. The piston valves 9I serve to open or shut, according to their position, oil

passages which run across the distributor par-- allel with its axis from inlet connections 93 (Figure 4) to outlet connections 94. When a piston valve is lifted by cam I2, its passage is closed and when the valve falls, it opens the passage. This can be best seen in Figure 'I where the passage I9I is shown closed by rea'son ofthe fact that the valve-is lifted by cam I2 and the groove I92 in the valve 91 is out of register with the passage. One such valve, with inlet and outlet, is appropriated to each of the engine fuel nozzles which is to'be controlled. Each of the inlets 93 receives-fuelunder pressure from the delivery box 52 of the fuel pump by means of appropriate pipe connections, some of which can be seen at 94, 95 in Figures 1 and 4. In these figshaft I3 so that its angular movements under chamber 21. 1

valve 24.

ures can also be seen a pipe connection 96 which leads from the'delivery box 52 to the top of the nozzles I00. A drain I03 from each of the fuelnozzles is connected toa return pipe I04 which returns any leaking fuel oil back to the tank IOI. A drain I06 returns fuel oil from the chamber 84. The oil from the chamber 34 is that which has been allowed to pass by the relief- Preferably the drain I08 is provided with a spring-loaded non-return valve of such strength as to retain oil in the chamber 34 at a low' pressure of approximately fifty pounds per square inch. The distributor I5, in the position of the piston valves 9| where they are lifted by cam I2, returns fuel oil from the pipes 94 into the chamber 34 by way of the passage formed by the flat I93 on the side of the valve 9! and the passage I94 in the body I5 of the distributor, thus allowing the nozzles I00 to open, whereas when thevalves are in their normal position, that is, not lifted by the cam I2, fuel pressure is'admitted topipes 94 and this keeps the nozzles I00 closed. By maintaining a residual pressure, suchas is referred to, in this chamber, complete release of pressure from the pipes 94 is prevented and the closing of the inJector nozzles 9 I00 is thereby rendered somewhat prompter. -A.

drain I06. carries fuel oil, it any, should such leak into'the chamberwhich contains the'g'ovf emor casing 2|, back to the fuel tank. It will be understood that the fuel tank III can be placed at any desired level and is only illustrated below the other parts in the figure for the sake of convenience in preparing the diagram.

The construction and operation of the fuel nozzles themselves are described in my co-pending patent application No. 225,024 of even date herewith.

Briefly stated, the nozzle comprises in the casing I a needle-valve I20 which is connected by a stem I23 to a needle-valve closing-piston I22 working in a valve-closing pressure-chamber I2I. Closing pressure on the needle-valve is further exerted by means of a spring I24. Drain pipe I03 is connected-to the space I 25 in which the spring I24 works. The needle-valve I20 has a seating in a detachable nozzle section I35 which contains the actual nozzle opening through which fuel is injected-into the engine cylinder.

The fuel pipe I02 from the pump 02 is connected to the back end of the fuel nozzle and thence by a passage I34 controlled by an auxilthe delivery 'box 02 to a control tap provided withna return connection to the tank IOI. If the tap is opened the pump is prevented from building up a pressure in the delivery box 02 and the engine is thereby stopped. When mounted on a motor vehicle, such a tap can be installed onthe dashboard of the vehicle. It constitutes an equivalent to the ignition key which is ordinarily provided on an automobile.

I claim:

1. Fuel injection apparatus for an internal combustion compression-ignition engine, com- .prising in combination fuel injectors on the engine cylinders, a pump for supplying fuel oil at injection pressure to the injectors, a distributor connected to the pump and the injectors for timing the operation of the injectors, said distributor having valves for controlling the flow of fluid under pressure to open and close the injectors and rotatable mechanical means for actuating said valves, a rotatable driving element,

adjustable operative connections therefrom to the said mechanical means which actuate the distribution valves such that the angular relationship between the driving element andthe said means may be adjusted, a control cylinder,

- anda yieldingly supported piston therein sub- When pressure is applied by the distributor through pipe 94, which is whenever the distributor valve 9| are not lifted by the cam 12, this pressure holds the needle-valve I20 on its seat owing to thepressure exerted in the chamber I2I on the piston I22 and also holds the auxiliary cut-ofi valve l32'on its seat "I, thus cutting ofl. fuel pressure'from the passage I34. At

the same time the valve I30 opens a drain passage by way of the grooves I30, I31, chamber I30,

channel I60, drain passage HI and apertures I42 to the drain I33.

Immediately the valve 0| is lifted by thecam 72 the pipe 94 is connected by the flat I33 'to the chamber I34 as already described, pressure in the valve-closing pressure-chamber I2I is released, the auxiliary' cut-ofl valve I30'is forced open by the pressure in pipe I02, thus closing the drain connection and opening the passage I34 to minating injection.

- Instead of using a multiplecylinder pumpa single cylinder pump could be used in the apparatus described herein in conjunction with an accumulator device connected to the delivery of the pump for maintaining the pressure between successive strokes of the. pump.

Owing to the operation of ,the plunger-operat-' ing rams 4|, 42 the volume of freespace -in-the chamber-which contains the cams 30, 40 varies during rotation of the cams. If desired this.

cyclic variation of volume can be used for delivering fuel to the fuel tank IOI. pose a suction pipe would be connected to the casing II, such pipe containing a non-return valve, the suction pipe being connected to a. main fuel tank, not, shown in the drawings. The

pipe I05 would be provided with a non-return valve at the outlet of the casing- II and would then deliver the fuel oil to the tank III.

It is also possible to take a connectionfrom ject to fuel-pump pressure operatively connected to the said adjustable operative connections to vary the said angular relationship and so determine the timing of the distributor.

2. Fuel-injection apparatus as claimed in claim 1, wherein a relief valve for controlling the fuel pressure is located in the wall of the control cylinder.

3. Fuel-injection apparatus as claimed in-claim 1, wherein a relief valve for controlling the fuel pressure is located in the wall of the control" cylinder and a centrifugal governor, driven by the same driving means as the mechanical means for actuating the distribution valves, supports the relief valve against the fuel pressure, so that the fuel pressure is proportional to the square of the engine speed.

a. Fuel-injection apparatus as claimed in claim 1, wherein a relief valve for controlling the fuel cylinder, a centrifugal governor resists openingof the relief valve, the governor and distributor are interconnected by a lay shaft having gears thereon meshing with gears on the governorand distributor shafts, said gears including helical toothed gears, one of which is axially slidable,

For this purconnected to'said yieldingly' supported piston and constituting the adjustable part of the operative connections from the driving element bywhich the angular relationship of the distribu,

tor thereto is adjusted. Y Y

6. Fuel-injection apparatus comprising in combination a centrifugal governor, an operating shaft therefor, a lay shaft, gears connecting the lay shaft with the operating shaft, a distributor and the distributor, a fuel pump delivering to said control cylinder, a relief'valve in said control cylinder, the opening of which is resisted by said governor, and a piston in said control cylinder coaxial with said distributor cam and so operatively connected thereto as to move the gear connecting the cam with the lay shaft axially under the influence of fuel pressure in the control cylinder, said gear having inclined sliding engagement with one of the members through which rotation is transmitted so as to advance said cam during said axial movement as fuel pressure increases.-'

7. Fuel injection apparatus as claimed in claim 6, wherein a pump-operating cam is provided upon the governor shaft and the pump is located so as to be actuated thereby.

' the lay shaft and'the pump is a dual barrel pump operated as to one barrel by the cam upon the governor shaft and as to the other barrel by the cam upon the lay shaft.

10. Fuel-injection apparatus as claimed in claim 6, wherein hand-operated means are provided connected to the lay shaft for additionally advancing and retarding the distributor relatively to the operating shaft.

' I GEORGE AMERY.

Images