US2554084A - Fuel pump for internal-combustion engines - Google Patents

Description

E m A N E B FUEL PUMP FOR INTERNAL-COMBUSTION ENGINS 3 Sheets-*Sheet l Filed Aug. 3, 1949 Mm WM l@ Mw M l wf@ Mw .ft M m Mm @M Y@ B 3 Sheets-Sheet 2 INVENTUR Maf/e7 /fA/ff//fA FUEL PUMP FOR INTERNAL-CMBUSTION ENGINES /IIIIIIISIIIl/IA Filed Aug. 3, 1949 xmf, 91W M /fm ATTORNEYS E m A N m E R.

FUEL PUMP FOR INTERNAL-COMBUSTION ENGINES 3 Sheets-Sheet 3 Filed Aug. 3, 1949 E/ w u Q I Q ATTDRNE Y? Patented May 22, 1951 FUEL PUMP FOR INTERNAL-COMBUSTION ENGINES Robert Bienaim, Paris France Application August 3, 1949, Serial No. 108,406 In France March 29, 1949 (Cl. 10B- 37) Claims. 1

The present invention relates to injection pumps and it is more especially but not exclusively concerned with pumps for injecting fuel into internal combustion or explosion engines.

Its chief object is to provide a pump of this kind which is simpler, easier to manufacture and adapted to the injection of liquids of all 1sinds (fuels, either of the lubricating kind or not).

It consists, chiefly, in varying the volume of liquid injected by providing means for causing the period of injection to occur for a different phase of the movement of the piece which produces a reciprocating flow of the liquid.

In order to separate the liquid to be injected from the lubricant present in the pump, I divide said pump into two zones. The first Zone is that in which there is at least one cylinder and one piston acting upon a lubricating or at least nonseizing liquid and which is controlled by a cam, an eccentric or the like, with a movement of sinusoidal or approximately sinusoidal law. The second zone is reserved to the liquid to be injected, such as a fuel.

These two zones are separated from each other by a diaphragm or the like, which serves only to transmit the flow of liquid, without itself undergoing any stress, the pressure being equal on both of its faces.

In the pump according to my invention a device, operated by rotation of a shaft, causes a liquid to move in a circuit with an alternating rate of fiow. During most of the period of said flow; the liquid moves in a closed circuit, but for a short portion of this period flow through the closed circuit is prevented and the liquid displaced during this portion of the period is caused to flow out, to produce injection.

Preferred embodiments of the present invention will be hereinafter `described with reference to the accompanying drawings, given merely by v way of example and in which:

with the lubricating liquid, more especially in the case of an injection pump for an-aviation engine, this device permitting of placing theI apparatus upside down.

On the diagram of Fig. 1, the abscissas indicate the anglesV of rotation of the shaft which controls, through a piston, the alternative flow of the liquid, whereas the ordinates designate the corresponding flow rates.

Injection takes place during the time corresponding to angle a (which is constant). When injection takes place at equal distance between the upper dead center and the lower dead center, it is maximum, as shown on the diagram at V. When a is located at the lower dead center, the injection is zero, as shown on Fig. 1 by D.

For all intermediate positions, the injection volume, designated by v, ranges from to V and-varies gradually between these two values.

Horizontal lines 71,1 and n2 represent respectively the bottom and top of the port or ports provided in the cylinder in which said piston is running and which limit the liquid flow.

I have shown two possible positions of these lines chosen in such manner as to obtain the maximum volume of injection as may be necessary.

This limitation of the liquid flow is of very high interest in that, as long as the piston is not moving between these limits, there is no flow of liquid.

Figs. 2 to 4 show, by way of example, a fuel injection pump for an internal combustion engine based upon the principle above set forth.

In a pump body constituted by several parts I a, lb, I c adjusted and juxtaposed together in a detachable manner and for instance by means of bolts, I provide two distinct mechanisms, one of which serves to propel the liquid to be injected and the other to distribute this liquid.

'Ihe mechanisms for propelling the liquid to be injected is constituted by a plunger 3 moving in a cylinder 4 fixed, for instance by threading at 5 in the bottom E of piece ib which closes a cavity l provided in the pump body la and filled with a lubricating or at least non-seizing liquid.

At a height defined by the maximum volume of liquid to be propelled I provide, in the wall of the cylinder, ports 8 which afford communication between the inside of cylinder l and chamber 1.

These ports are closed by plunger 3 when the free end 9 thereof penetrates into the lower portion lil of cylinder 4. This portion lll communicates with a conduit Il which opens into a space [2a separated by diaphragm 2 from another space 12b.

The reciprocating movement of plunger 3 in cylinder 4 is obtained through the action of a cam I3, for instance an eccentric, rigid with shaft I4, which carries a helical gear I5 at one of its ends.

There is one cam I3 for every cylinder of the engine. Each cam pushes its plunger 3 into the corresponding cylinder 4 against the action of a return spring I 6.

When ,plunger 3 is in its upper position (as shown by the drawing) chamber l communicates freely, through port 8, with the inside of the cylinder and, therefore, with conduit II and space I2a.

When the plunger moves downwardly, under the action of cam I3, it first comes to cover port 8 (this position corresponding .to :level n1 or n2 of Fig. l) and then drives the liquid contained in conduit II and space 12a, so that this liquid can act upon diaphragm 2 tok discharge the fuel present in the other zone or section yof the pump.

Fuel is supplied to pump body I c from a gravity tank or from .a pump and it is fed through `a passage I'Ia (Fig. 3) to a chamber I'I-common 'to the feed means of all the cylinders.

closed at the top 'by a flexible diaphragm I8,

analogous to diaphragm 2 and tightly caught between the edges of piece Ic and a guide cover I9.

The fuel distributing device is constituted (Fig. 2) by a valve 2D (one for every engine cylinder) which controls the now of liquid through an orifice .2l provided in the bottom of chamber II, in Apump body ic.

Valve 20 is fitted on a rod subjected to .the action of a return spring 24, which extends, in a fluidtight manner through diaphragm L3 yand which is guided by cover I9.

'Ihe upper end of this rod, which is located in chamber .'I, carries an adjustable head 23, fixed by means of a counter-nut and .subjected to the action of a cam carried -by a shaft 2B parallelto shaft I4.

This shaft carries a helical gear 2l in mesh with gear I5 `and is driven through its .end 28, which projects from the pump body.

Helical gear 2'! is slidably adjustable-on shaft .26, owing to the provision of a .feather key 35. Sliding displacement of gear 2'I .on its shaft is controlled by means of a fork 36 actuated '.by means of a spindle 37 controlled by a lever Sla .operatively connected with the throttle of the engine.

Since gears I5 and 2'! are helical gears, displacement of gear 2l under the action of fork 36 modifies the relative angular positions of the two shafts.

In the example shown by the draw-ings, cam 25 is circular at 3i! over most of its outline. It includes a recessed portion, for instance of flat shape, 3|, owing to which valve 2i] closes for a short time under the action of its return spring 24.

For the remainder of the rotation -of the cam, valve 2B remains at a distance from its seat, thus ensuring freecommunication between conduit 32 and chamber I'I. Conduit 32 rconnects space I 2b, adjacent to diaphragm 2, with .a discharge valve 33.

.Diaphragm 2 causes fuel to be delivered by discharge valve 33 when valve 2U is closed. This fuel therefore meets no part having a substantial friction and it is wholly Aseparated. by diaphragms 2 and I8 from the propelling liquid of chamber IY'I.

Furthermore, as the angular position of shaft 26, with respect to its driving portion 28 and therefore to the engine, has not been modified, injections take place at times which are uninfluenced by the importance of the delivery.

It is clear that a supplementary device, not described, can modify the position of shaft 2G with yrespect to .the driving shaft, if it is desired to vary the lead to injection.

Of course the helical gear arrangement shown by the drawing is given merely as an example of means for modifying the angular position of `shaft lI4 with respect to that of shaft 26.

In the example shown, cam I3, which operates veach of ,the plungers, is constituted by an eccentric of circular section whereby the plunger moves with -a sinusoidal law of movement, but this lcam might be of different shape to obtain a quicker or slower variation of volume, as required.

It will be noted that diaphragm 2, at lthe place where it is held between parts Ib and Ic of the pump, is in contact with rounded edges 38. A transverse slot 39 provided in each of these edges, permits of evacuating all gases, which avoids the formation of gas cushions.

Diaphragms 2 and I8 may be made of natural, synthetic rubber or any other suitable material and they may also be replaced by other elastic devices, such as metallic bellows.

In some cases, the injection pump must be able to work in all positions and even when upside down. In this case, chamber l, reserved to the propelling liquid, must contain no trace of gas and must be wholly lled with liquid.

In order to obtain this result, it is advantageous to have recourse to the arrangement illustrated by Fig. 5.

In alateral wall 40 of chamber 'I, .I provide a hole 4I and in this hole I house an elastically deformable member, for instance an elastic bellows 42.

This member is fixed on wall 4E) by a vplate 43 and screws `44. On the end plate of the bellows, I fix the inner end of a rod 45 which extends through plate 43 and the outer end of which is fitted witha control knob 46. A spring 4l is placed between a plate 43 and the end plate of bellows 42.

,In order t0 ensure complete filling of chamber 'I with a lubricant or any other suitable liquid, plug 48 is removed and liquid is introduced through the filling hole 49 thus opened. When the chamber is lled, rod 45 is pulled out, which compresses the bellows and permits of introducing a certain amount of liquid into chamber l. Plug 48 is then screwed in position and knob 46 is released. Bellows 42 therefore exerts a pressure upon the liquid present in chamber l. As unavoidable leakage takes place, expansion of the bellows compensates it and chamber 'I remains lled with liquid.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. An injection pump which comprises, in combination, a pump body forming a closed chamber filled with a lubricating liquid, a fuel intake chamber and a fuel delivery conduit, with an elastic diaphragm interposed between said closed chamber and said delivery conduit and another elastic diaphragm interposed between said closed chamber and said intake chamber, said pump body being provided with a passage between said delivery conduit and said intake chamber, an injection control valve movable in said pump body for closing said passage, a discharge valve at the outlet of said delivery conduit, driving means in said closed chamber for forcing a flow of liquid therein toward said first mentioned diaphragm with a periodically alternating rate of iow, control means operatively connected with said driving means for periodically moving said valve into closing position once for every period of variation of said flow rate and always for the same fraction of said period, and means for varying the phase relation between the operations of said driving means and said control means respectively.

2. An injection pump which comprises, in combination, a pump body forming a closed chamber filled with a lubricating liquid, a fuel intake chamber and a fuel delivery conduit, with an elastic diaphragm interposed between said closed chamber and said delivery conduit and another elastic diaphragm interposed between said closed chamber and said intake chamber, said pump body being provided with a passage between said delivery conduit and said intake chamber, an injection control valve movable in said pump body for closing said passage, a discharge valve at the outlet of said delivery conduit, a cylinder interposed between the portion of said closed chamber adjacent to said rst mentioned diaphragm and the remainder of said closed chamber, said cylinder being provided with at least one lateral port, a plunger slidable in said cylinder, driving means for reciprocating said plunger in said cylinder with a constant amplitude, control means operatively connected with said driving means for periodically moving said valve into closing position once for every inward stroke of said plunger and always for the same fraction of its period of reciprocation, and means for varying the phase relation between the respective operations of said driving means and said control means.

3. A pump according to claim 2 in which said closed chamber includes a bellows located inside said closed chamber, elastic means for urging said bellows to expand, and means operative from the outside of said closed chamber for retracting said bellows.

4. An injection pump which comprises, in combination, a pump body forming a closed chamber lled with a lubricating liquid, a fuel intake chamber and a fuel delivery conduit, with an elastic diaphragm interposed between said closed chamber and said delivery conduit and a fluidy tight partition interposed between said closed chamber and said intake chamber, said pump body being provided with a passage between said delivery conduit and said intake chamber, an injection control valve movable in said pump body for closing said passage, a discharge valve at the outlet of said delivery conduit, driving means in said closed chamber for forcing a ow of liquid therein toward said diaphragm with a periodically alternating rate of flow, control means operatively connected with said driving means for periodically moving said valve into closing position once for every period of variation of said flow rate and always for the same fraction of said period, and means for varying the phase relation between the operations of said driving means and said control means respectively.

5. An injection pump which comprises, in combination, a pump body forming a closed chamber filled with a lubricating liquid, a fuel intake chamber and a fuel delivery conduit, with an elastic diaphragm interposed between said closed chamber and said delivery conduit and a uidtight partition interposed between said closed chamber and said intake chamber, said pump body being provided with a passage between said delivery conduit and said intake chamber, an injection control valve movable in said pump body for closing said passage, a discharge valve at the outlet of said delivery conduit, a cylinder interposed between the portion of said closed chamber adjacent to said diaphragm and the remainder of said closed chamber, said cylinder being provided with at least one lateral port, a plunger slidable in said cylinder, driving means for reciprocating said plunger in said cylinder with a constant amplitude for periodically forcing a flow of liquid into said portion of the closed chamber adjacent to said diaphragm, control means operatively connected with said driving means for periodically moving said valve into closing position for every inward stroke of said plunger and always for the same fraction of its period of reciprocation, and means for varying the phase relation between the operations of said driving means and said control means respectively.

ROBERT BIENAIME.

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

UNITED STATES PATENTS Number Name Date 2,289,617 Wood July 14, 1942 2,301,407 Houser et al. Nov. 10, 1942 2,343,962 Dodson Mar. 14, 1944 2,395,330 Houser Feb. 19, 1946

Images