US2102485A

US2102485A - Fuel injection means for motors

Info

Publication number: US2102485A
Application number: US18395A
Authority: US
Inventors: Riegels Olaf Leonha Augustinus
Original assignee: Individual
Current assignee: Individual
Priority date: 1935-04-26
Filing date: 1935-04-26
Publication date: 1937-12-14
Anticipated expiration: 1954-12-14

Description

Dec. 14, 1 937. o. L. A. RIEGELS FUEL INJECTION MEANS FOR MOTORS Filed April 26, 1935 2 Sheets-Sheet l INVENTOR CILAP LARIEEELE.

7 5/. new

ATTORNEY Patented Dec. 14, 1937 UNITED STATES PAT'ENT' OFFICE ()laf Leonhard Augustinus RiegelslfCleveland,

. Ohio Application April 26,

Claims.

This invention relates to fuel oil injection means for direct'injection oil engines or motors, and has particularly reference to those of the Diesel type.

5 Because of very pronounced pressure fluctuations occurring in the'fuel line during fuel injection, a constant and gradual injection of fuel oil cannot be obtained under present practice in this art; and because of the extremely low compressibility of the fuel oil and the high rigidity ofthe enclosing structure, the time-interval of the pressure fluctuations is very short, and accordingly a number of such fluctuations :take place in the time necessary for and during a single gradual injection of the fuel. One object'of this invention is to reduce or eliminate these fluctuations.

In an injection apparatus or nozzle and in the fuel line of a Diesel engine, two kinds of fluctua- 2 tions or waves are ordinarily observed and known to exist. One kind originates at the fuel pump,

due to the compression of the fuel and exists in the fuel line and in the injection nozzle, when the latter is closed by the nozzle valve. These n fluctuations are known as and have the character of pressure waves, but they are not important as they have a relatively low frequency and their tion valve, fluctuations or waves are built up,

which travel from the nozzle tip to the end of fuel supply pipe or pump plunger and back and forth again. These waves have the character of rarefaction or tension waves and are very violent and cause at their maximum amplitude a considerable pressure drop, which reduces the pressure to an amount much less than is necessary 43 to sustain a continuous and gradual injection.

If said tension waves are damped out or balanced by pressure waves of equivalent frequency and intensity and opposite phase, a.continuous and gradual fuel injection results.

is, according to the present embodiment, accomplished by a stop or bypass valve placed in a bypass opening and operated by elements co-acting with the nozzle valve, to move oppositely with respectthereto, so as to effect a closure of the one as the other is opening. Accordingly, another This action 1935, Serial No. 18,395

Another object of the invention is to provide.

Another object of the invention is to construct an improved fuel injection nozzle having a stop valve provided with a removable valve seat.

A further object of this invention is to provide an improved fuel injection means having an injection valve and a stop valve the openings of which are of predetermined correlated size to insure a balanced wave re-action during fuel injection.

. Other objects of the invention will be apparent to those skilled in the art towhich my invention relates from the following description taken in connection with the accompanying drawings, wherein Fig. 1 is a view, partly in elevation and partly in section, of an engine'embodying-my invention.

Fig. 2 is a fragmentary section of parts shown in Fig. 1, enlargedv Fig. 3 is a sectional view of the fuel pump, enlarged.

Fig. 4is a view of parts shown in Figs. 1 and 2, slightly modified and partly diagrammatic.

Fig. 5 is a diagram.

In the drawings, A indicates as an entirety an engine of the Diesel type, showing one cylinder B and a piston C therein. The engine may be constructed to provide any number of cylinders, as

desired, but as my improved injection means is applied to each cylinder, only one thereof need be illustrated and referred to. D indicates a piston rod, which drives a crank shaft E. The shaft E is drivingly connected to a cam shaft F which, through' the rod f and rocker 1, time controls the usual exhaust valve to the exhaust manifold G. H indicates, the fuel pump having a fuel inlet h connected with a pipe leading from a suitable soiu'ce of supply and a fuel outlet 71. connected to a conduit ,1. "The shaft 1' of the.pump is suitably driven, for example. by the gearing shown in Fig. l, to rotate a cam which'in turn, in cooperation with a spring, operates the pump plunger i. The pump H serves to supply the fuel. to the injection nozzle, as hereinafter set forth, at relatively high pressure. Any desired construction of pump for this purpose may be used, that shown being for illustrative purposes only. a indicates a casing formed integrally with the "cylinder head a" and shapedto form axially of the cylinder B a tubular wall I), enlarged at its upper end, to receive and support the injection valve'nozzle structure, the head a being formed with an opening b axially of the cylinder to receive a portion of the structure, as later described.

I indicates a hollow body member of the injection valve having a main portion la, an integral neck portion lb at its lower end (these portions being seated in the wall b) and an integral head is at its upper end. The lower end of the neck portion lb is preferably of conical shape to which is axially related a removable, tubular tip member 2 removably fitting at its lower end into the opening b, and having at such end an end wall formed with a nozzle opening 20,. The inner wall of the tip member adjacent its end wall is cut away to form a chamber 2a:. The upper end of the opening 2a is of conical shape to form the valve seat 20. of the movable injection valve element 3 to be later referred to. The tip member 2 is reduced in diameter throughout a portion of its length to form a shoulder 2', which is engaged by a shoulder on a sleeve'2c, the upper end of which is'threaded on the lower end of the neck portion lb to removably secure the tip member in position. The head I 0, main body portion Ia, neck portion lb and tip member 2 are formed with ducts in connected relation to provide a fuel supply conduit 4 suitably connected at its upper end with the conduit I and leading to the chamber 2.1:5'also these parts are formed with ducts in connected relation to provide a fuel conduit 5 leading from the chamber 21: to an outlet 6, connected to a pipe 1, which leads to the fuel supply or storage tank (not shown). A stop valve 8 is providedin the conduit 5, forming a valve controlled bypass, for a purpose later set forth.

The injection opening through the tip member 2, located between the valve seat 2a and the engine cylinder, is accurately sized to permit the passage therethrough of exactly the desired amount of fuel required by the particular engine to which the injection valve is applied when the valve element 3 is moved from its seat to give free flow of fuel from the pressure feed line I to the engine cylinder.

The shank 3a of the injection valve 3 slidably extends through the neck lb and an opening in a plug 9 threaded in the upper end of the main portion la, the upper end of the shank 3a being threaded to adjustably support a cap I0, which is engaged by one arm of a rocker H suitably fulcrumed on a standard I2. The plug 9 serves as an abutment for one end of an expansion spring I3 coiled around the shank 3a, the other end of the spring engaging a collar [4 fixed to the shank and normally acting to seat the valve 3 against its seat. The plug 9 is positioned in the body portion la. so as to adjust the tension of the spring to the predetermined pressure desired to effect or permit opening of the injection valve 3. The lower end portion of the shank 3a is reduced to form an annular shoulder 3 against which the fuel pressure acts to unseat the valve 3.

The stop valve 8 comprises a seat member 8a removably mounted in an opening formed in the head lo and a plunger 8b, the lower end of which forms the valve element to engage the seat member. The opening through the seat member communicates with the adjacent ducts of the conduit 5. The upper end of the opening in the seat member 8a is of conicalshape to form the seat for the similarly shaped lower end of the plunger 8b. The plunger slidably fits an opening formed in a plug l5 threaded'into an opening formed in the head lo, the upper end of the plunger 8b being arranged to be engaged by the other arm of the'rocker H. The upper end of the plug I5 is provided with a boss to which a split collar l6, which is connected to the standard I2, is suitably clamped. As the rocker ll engages the plunger 8b and shank 3a, the injection valve 3 is closed when the stop valve 8 is opened, and when the valve 3 is opened, valve 8 is closed.

Fuel supplied under pressure by the pump H flows through the conduit 4 to the injection valve 3 and if the latter is closed, the fuel flows through the conduit 5 to the return pipe 1, the pressure of fuel serving to lift the plunger 8b and permit such fuel flow to the pipe 1. This fuel fiow per mits air contained in the fuel line to escape and those pressure waves originating at the pump and caused thereby during this stage of opera tion to be eliminated so long as the injection nozzle valve remains closed. As soon as the pressure of the fuel rises to a point sufi'icient to overcome the pressure of the spring l3 (which spring pressure is adjusted to a predetermined tension dependent upon the area bf the valve 3) the resulting fuel pressure acting on the shoulder 3, which has an area larger than that of the valve element 3, will lift the valve element 3 from its seat, permitting the injection of the fuel into the combustion chamber or cylinder.

Because of the low pressure in this chamber, compared with the high pressure of the fuel, the

fuel will tend to regain its original or normalv density and volume, in proportion to said pressure difference, resulting in a sudden pressure drop in the injection nozzle, and as the compressibility of fuel oil is very low, and said pressure difference is very high, this sudden drop in pressure creates a tension or rarefaction wave,

which travels from the injection nozzle tip to the pump or pressure source and back and forth. As the time period of these waves is very short compared with the time of injection for Diesel cycle operations, these waves or fluctuations, of which a plurality occur during each injection, prevent gradual fuel injection.

When the injection valve 3 lifts, it operates the rocker which in turn closes the stop valve to stop the flow of fuel through the conduit 5, the effect of which, due to the sudden check in the velocity of the fuel, is to cause a pressure wave of equal frequency and of opposite phase to that of the tension wave and traveling from the stop valve to the pump and back and forth. These tension and pressure waves just referred to havepractically the same period (the difference between them in this respect being so slight as to be immeasurable and hence may be disregarded) and if their amplitudes be the same they may be caused to neutralize or damp out each other so that they have nopractical effect in the injection nozzle, with the result that a grad-- nail and continuous injection of fuel into the combustion chamber takes place.

To secure this wave balancing eifect in order to insure a smooth flow of fuel into the engine cylinder it is especially important that the waves of force of opposite phase,-the tension waves originating at the injection valve and the pressure waves originating at the by-pass or stop valve,-shall accurately oppose each other, as distinguished from being in more or less staggered or out of step relationship, as has been the case in earlier attempts to obliterate these waves of force which interfere with proper fuel feed. I have discovered that this accurate harmonic opposing of these waves of opposite phase may be accomplished by properly operating the injection and the by-pass or stop valves with relation one to the other. Thus theinjection valve is so operated that its discharge passage 2b into .ceedingly short movement of the valve stem 3 at the beginning of the movement of the valves insures this full fuel feed opening,further movement of the valve stem 3 not affecting the opening or size of the fuel passage 2b. On the other hand the movement of the stop or by-pass valve must be gradual in its control of the flow of fuel through passage l8, this being insured by operating this valve so as to much prolong its flow-restricting or accelerating movements; for, as will be seen by reference to Figure 4 when the valve stem 8 moves with reference to the seat 8a the flow passage to.the port I8 is gradually varied in size by reason of the relatively long taper at the end of the stem.

I not only secure this accurate positioning in harmonic opposition of the waves of opposite phase, but I cause such opposing waves to be. of equal force so they counter-balance each other, thus losing their interfering effects upon the flow of fuel which passes on into the engine cylinder as a smooth, steady stream. To insure this latter result I co-ordinate the discharge apertures in the two valves as to their sizes or areas in proportion to the differences in pressure on the delivery sides of the two valves.

It is evident that the flow of fuel through the injection valve is from the fuel line where the pressure is high,let it be assumed 4000 lbs. per

sq. in.,-into the engine cylinder where the pressure is much lower,-perhaps 500 lbs.; and that at the stop valve the flow is from the high pressure fuel line into the return pipe where the pressure may be atmospheric or thereabouts. Thus there is a very considerable difference in the pressures of the fluid passing the two valves respectively; and, since the volume of fuel passing the port or opening of a valve is governed both by the difference in the pressure of the fuel on the two sides of the valve, and the size of the port throughwhich it is flowing, it becomes necessary, in order to secure the desired results in the counterbalancin'g, and neutralizing of the effects of the waves of force traveling through the pressure column of liquid when the valves are operated, as has been described, that there be uniform volumetric flow through the two valves when they are operated. I have discovered that due to the facts just stated the fuel passage through the stop valve must be slightly smaller than the corresponding passage through the fuel injection valve, as they are simultaneously operated, to effect this desired result and insure a uniform delivery of fuel to the injection nozzle.

To insure accuracy, the mounting for the rocker Il may be adjusted laterally the effect of which is to change the length of the rocker arms relative to the points of contact with the shanks of the valve elements.- This adjustment is'preferably provided for by an eccentric ll" having an extended end (not shown) to permit its operation and suitable means for securing it in operated position. In connection with such adjustment, the cap Ill may be adjusted to provide the accurate relationship between the valves; also the plunger for valve 8 may be provided with an adjustable cap, similar to cap l0, if found'to be desirable.

If a wider seat for valve 3 is needed, for ex- I ample where a multiple hole nozzle tip or a pintle type-of nozzle valve is used I can either provide the proper size seat openings by the use of correspondingly different valve seat angles, or by a combination with different rocker arm lengths as described, or I can use equal valve seat diameters in combination with equal discharge openings.

Fig. 4 shows a valve head arrangement embodying the several features of my invention. Referring to this view it will be seen that the injection afull 0pening of the engine cylinder injection v passage, while a further movement of the valve stem has no effect on the size of such passage. On the other hand the taper of the by-pass valve stem 8 is longer and more gradual than that of V the stem 3 with the result that the change in the size of passagebetween the seat 80. and the taper of the valve stem 8 takes place throughout the full movement of the stem,from full open to completely closed position and vice versa,--so that the starting of the operation of the by-pass valve,- either to open or to close-is synchronous with the simultaneous movements of the two valves.

From the foregoing description it also will be understood, that a change of type of the injection valve 3, or the slightest change of the amount of discharge through said valve, will call for an equivalent change of the character of the stop valve 8 and its discharge opening. To permit of change in the seat of the stop valve, I provide its seat in an insert member 8a, which is readily accessible and removable and is constructed to have the discharge passage l3, of the proper size such as has been described, located at such distance from'the seat 8a with which the tapering valve stem 8 cooperates as permits the gradual closing and opening movements of the valve as has been .pointed out.

cated at 39, 39a, 39b, etc. represent the time period of the tension waves and pressure waves.

When the injection nozzle 3 starts to unseat at point 40, the compressed fuel rushes out, represented by line 49, trying to accelerate to a velocity of full flow at line 31, but before it reaches this point it expands to its normal density which results in a sudden pressure drop, which maximum at point 4| will occur in the time interval represented by 39, and immediately surge up again to a maximum pressure at 42, followed by a maximum drop again to point 43, which action will be repeated in the character of tension waves, and having a constant time period from point 40 to 4|, from 4| to 43, etc. represented by the constant equal length of

lines

39, 39a, 39!), etc.

As these fluctuations under practical conditions are repeated several times in the duration of each injection, represented by the length of line 38, a gradual or uniformly smooth injection has hither-v to been impossible. But, when the injection valve and operating conditions.

3 starts to-unseat the stop valve 8 simultaneously starts to close, and as the momentum of the suddenly stopped fuel column in conduit 5 is equal to the momentum of the fuel column in conduit 4 suddenly released by valve 3, a pressure wave 44 is originated, which maximum pressure is reached at point 45 having precisely the same frequency and intensity and of opposite phase as the tension wave 49, and thus the forces are balanced as described. The pressure rise represented by the length of the line 41, will precisely balance the pressure drop represented by the line 46. As all of the following pairs of pressure and tension waves will likewise become balanced, an effective pressure, represented by the line 48, will result in a controlled constant and gradual injection practically free from fluctuations.

It will be observed that the tip or valve seat member 2 of the injection valve, and the seat member 8a of the stop valve, are both relatively simple parts and are arranged and mounted so as to be easily removable and replaceable without disturbing the other parts of the entire valve assemblies. The purpose of this arrangement is this: in practice the two valve assemblies-the injection valve and the stop valve--are standardized so as to be fitted to engines of varying sizes But for each different size of engine and for engines of the same size where operating conditions are Widely difierent, the flow of fuel past the two valves must be determined and the flow in the separate valves accurately related one to the other in order that the discharge of fuel into the engine cylinder shall be steady and uninfluenced by the periodically recurring fluctuations in pressure which take place in the vicinity of both of the valves, and due to their movements, whenever they are operated. This adjustment of the valves to suit sp'ecial sizes and conditions of engines is determined by theoretical calculation, or trial and test for the particular engine in question, or by a combination of these methods of determination as to the proper parts to be used. These latter being determined upon may be easily inserted into their proper positions in the engine without disturbing the other parts of the valve assemblies.

To those skilled in the art to which my invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. My disclosures and the description herein are purely illustrative and not intended to be in any sense limiting.

What I claim is: l

1. A fuel injection apparatus for internal combustion engines, which includes a source of fuel supply under high pressure, a normally closed spring-controlled injection means comprising a valve seat having a discharge opening of predetermined size governed by the desired discharges into the engine cylinder, and a movable element co-operating with such valve seat, a bypass means for periodically by-passing fuel to said source of supply and comprising a valve seat having a dischargeopening and a movable valve element cooperating with said seat, the related surfaces of said last mentioned valve seat and valve element serving gradually to open or close the discharge opening through the valve seat during the movement of said valve element, the discharge opening through said last mentioned valve seat being smallerthan the discharge opening through said injection means valve seat and said openings being proportioned to the relative pressures respectively beyond the same, the higher pressure being beyond the injection valve where it discharges into the engine cylinder, and means for operating said movable valve elements for effecting the opening of one valve simultaneously with the closing of the other, said means being co-ordinated with the relative sizes of said discharge openings to insure equal volumetric flow through said openings.

2. An apparatus such as described in claim 1, wherein the valve operating means comprise a rocker engaging the valve elements of said valves arranged to close one valve when the other is opened, the arms of said rocker being related to the relative sizes of the openings for said valves to provide for the same volumetric discharge of fuel through one when open as through the other when the latter is open.

3. An apparatus such as described in claim 1, wherein the valve operating means comprise a rocker engaging the valve elements of said valves arranged to close one valve when the other is opened, the arms of said rocker being related to the relative sizes of the openings for said valves to provide for the same volumetric discharge of fuel through one when open as through the other when the latter is open, and means for adjusting the fulcrum for said rocker.

4. An apparatus as claimed in claim 1 wherein the movement of the valve element of the injection valve away from its seat by the operating I means terminates when the valve element of the by-pass valve closes its valve, and the movement of the valve element of the by-pass valve away from its seat by the operating means terminates when the valve element of the injection valve closes its valve.

5. The herein described method of operating an internal combustion engine of the Diesel type, wherein is employed a feed system of fuel under pressure, including a source of supply, a fuel line to an engine cylinder, a return line to the source of supply and a normally closed injection valve in the fuel supply line, which method consists in operating the injection valve, in synchronized relation to the compression stroke of the engine piston, through a predetermined cycle and causing an opening of its injection port to provide a predetermined volume flow of fuel in the initial portion of the cycle, maintaining such opening through an intermediate portion of the cycle and finally closing the injection port in the latter portion of the cycle whereby tension Waves are set'up in the fuel, and simultaneously in the return line beyond the injection valve and during and throughout the complete cycle of movement of the latter valve, checking the flow of fuel through a port of smaller area than the port of the injection valve to set up pressure Waves which are of opposite phase to the tension waves and controlling the pressure waves so that they start at the time the injection valve starts to open and are stopped at the time the injection valve closes.

OLAF LEQNHARD AUGUSTINUS RIEGELS.