US2520537A - Electromechanical high-speed operating gear - Google Patents

Description

Aug. 29, 1950 J. FORMAN ELECTROMECHANICAL HIGH-SPEED OPERATING GEAR 4 Sheets-Sheet 1 Filed Jan. 2, 1947 Aug. 29, 1950 J. FORMAN 2,520,537

ELECTROMECHANICAL HIGH-SPEED OPERATING GEAR Filed Jan. 2, 1947 4 Sheets-Sheet 2 Aug. 29, 1950 J. FORMAN 2,520,537

ELECTROMECHANICAL HIGH-SPEED OPERATING GEAR Filed Jan. 2, 1947 4 Sheets-Sheet 3 Aug. 29, 1950 FQRMAN 2,520,537

ELECTROMECHANICAL HIGH-SPEED OPERATING GEAR Filed Jan. 2, 1947 4 Sheets-Sheet 4 5 M64 M flMMM z Y/M Patented Aug. 29, 1 950 nnno'rnoMEonANIcALHIGH-sense OPERATING GEAR Jan Forman, Cambridge, England Application JanuaryjZ, 1947, Serial No. "ll9,671- In Great Britain December 31, 1945' Section; 1, Public Law 690, August S, 1946 Patent expires December 31, 1965 15 Claims. (o1. ale -130) l This invention relates to electro-mechanical high speed operating gear and may be employed Wherever it is required to obtain a' very high speed, accurately timed, short travel mechanical movement. I I

There are innumerable. machines in which parts are requiredto move at very high speeds over short distances. Hitherto such movements have generally been obtained by purely mechanical means, e. g., by quick lift cams hammer-blow mechanisms and the like. Such mechanical means are far from satisfactory: because of the heavy loading involved wear is rapid, great difilculties are experienced in preventing exces sive noise and such mechanisms have to be made very accurately and of very hard materials so that they are costly to manufacture. Moreover, owing to mechanical inertia, there are undesirable limits to the speeds of movement which can be obtained with accuracy by mechanical means. This invention seeks to avoid these defects and limitations and to provide electromechanical means whereby very high speed, and if required, accurately timed, short travel poweri'ul movements can be obtained and which shall be comparatively simple, reliable and compact.

The invention is of very wideapplication to machines of very widely different classes too numerous and diverse to be listed, but among the applications of the invention. may be mentioned, purely by way ofv example, the operation of power presses and the operation of thevallves of an internal combustion engine, in. particular a fuel injection Diesel engine, since these two cases are typical examples of the problems which the invention seeks to solve. The latter casethe operation of the valves of a fuel injection Diesel engine-vvil1 be considered first. Ideally, a Diesel engine fuel injection valve is required to open instantly and accurately at a predetermined. point in the cycle of engine operation. Obviously this theoretical ideal is unattainable since some time must be occupied in opening. In modern internal combustion engine design great care is taken to ensure that the valves shall move from their fully closed to their fully open positions as rapidly as possible and much trouble and cost is incurred in the design and manufacture of quick lift cams, in the reduction of the reciprocating weight of valve gear and in other design expedients havinghigh speed operation as their end. Nevertheless, the me chanical limitations of cam actuated gear are such that even with the most carefuldesign and manufacture the results achieved fall. far short or the ideal and it may be fairly said that the limit of improvement with the usual known cam operated gear has almost been reached and there is little prospect of any great further advance. By applying the present invention to the actuationof Diesel and other internal. combustion engine valves the said valves may be actuated considerably more rapidly than is possible by cams or the like and with highly accurate timing.

Again, as is wellknow'n, the effectiveness and efiiciency of a'power' press isvery'largely dependent upon the speed and accuracy'of movement of the press tool and in this case also it may be said th'at'the limit of improvement with the usual mechani'cally operated power presses has almost been reached. By applying the present invention to the operation of a power press considerably faster'movement of the press tool withvery great accuracy can be achieved.

, According to thisinvention electro-mechanica'l high speed operation gear comprises a storage system for electrical energy, means for suddenly discharging energy from said system into a discharge circuit at a predetermined time, a repulsion coil in. said discharge? circuit, a non-ferromagnetic repulsion member of good electrical conductivity adjacent said repulsion coil, and means for utilising, to actuate a mechanical member to'be moved, the force of repulsion set up between said repulsion coil' and said repulsion member when said discharge occurs through the repulsion coil circuit.

Very large forces and values of acceleration areavailable from an arrangement in accordance with this'i'nvention the force increasing with the value of current through the coil-and the acceleration increasing with therate of increase of current. To give but one example, experimentally tested, a coil associatedwith a member in the form of a copper ring weighing 160 grammes and arranged to reach a current of 3000 amps. in i of asecond produced a force of the order of 5000 kilogramme's and an acceleration of the order of 100,000 gravitie's'on the ring.

Preferably the electrical storage-system com prises an electro-static condenser which is charged to a high voltage from a mains or other source and discharged suddenly, at the required time through a discharge circuit" whose induct since is such that, with the value" of capacity employed and the ohmic resistance of the coil winding, the damping is less than the critical value,.i. c-1230 should be lessthan 4L- for the circuit. In the numerical. exampleinthe imme diately preceding paragraph a condenser of mfds. charged to 5,500 volts was employed, the discharge circuit presenting an inductance of 500 microhenries and a resistance of 0.15 ohm. This gave a damped oscillatory discharge at about 600 cycles per second in which a peak current of about 3000 amps. was reached at the end of the first quarter cycle. Of course, forces of this magnitude may not always be required: for example, to operate the fuel injection valve of a Diesel engine, a condenser of from 8 to 12 microfarads charged to about 2000 volts will develop sufficient force.

My invention will be more fully understood from the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 schematically shows the system of my invention applied to the control of a shaft member at very high speed; Fig. 2 is a detail view of the repulsion member employed in the system of Fig. 1; Fig. 3 shows a modified form of spring controlled repulsion return action that may be employed in the system of Fig. 1; Fig. 4 shows schematically a magnetic return action that may be employed in lieu of the spring or repulsion return action of Fig. 3; Fig. 5 shows a modification of the magnetic return action of Fig. 4; Fig. 6 shows a further modification of the spring action in which the repulsion member is in the form of a truncated cone; Fig. 7 shows another form of magnetically controlled repulsion system; Fig. 8 shows a circuit arrangement for the system of my invention applied to the throttle control of an engine; Fig. 9 shows one arrangement of timing means for triggering a Thyratron in accordance with my invention; Fig. 10 shows a capacity control system which may be used in lieu of the arrangement shown in Fig. 9; Fig. 11 shows a fragmentary portion of a Thyratron control circuit in which control windings are provided for magnetically opening and closing a Valve or other means; Fig. 12 is a vertical sectional view taken through a centrifugally controlled electrical condenser used in one form of control system of my invention; Fig. 13 is a front elevational view of the centrifugally controlled electrical condenser shown in Fig. 12; Fig. 14 shows the system of my invention applied to the control of a group of four high tension dynamos; Fig. 15 is a detail view showing the manner in which condensers employed in the circuit of Fig. 14 may be charged through seperate rectifier circuits in accordance with my invention; Fig. 16 shows a modified form of condenser charging circuit which may be used in the system of my invention; and Fig. 17 shows a further modification of a control circuit embodying my invention in which a single condenser is employed for a multi-cylinder engine and connected through a main Thyratron across a suitable voltage source so as to be charged thereby once per revolution of the engine.

In carrying out the invention, the non-ferromagnetic conductive memberhereinafter called the repulsion membercan be used as the moving member, or the coilhereinafter called the impeller coil-may be so used or both may be so used. Movement in one direction may be achieved in accordance with this invention and return movement may also be achieved by means in accordance with the invention, e. g., by another coil acting on a repulsion member or in any other way dependent upon the requirements of the machine to which the invention is applied. For example, return movement may be effected by means of a coil operating on a ferro-magnetic member as in an ordinary solenoid. In some cases in which the primary movement effected in accordance with this invention is effected with large forces, the use of an ordinary D. C. fed solenoid for the return movement will be unsatisfactory, involving the provision of a solenoid of inconveniently large size and power rating. In such a case a second condenser, charged from a convenient source, may be provided and discharged through a comparatively small solenoid to effect the return movement. In general, in such a case, the solenoid should be of sufficient number of turns to bring the inductance and resistance values of its circuit beyond the point of critical damping (having regard to the capacity value of the circuit) so that there occurs in the solenoid a relatively slow pulse of uni-directional current of a peak value much higher than would be permissible in a solenoid of the same design operated as in the ordinary way by D. C. In this way a pulsed magnetic field operating on the ferromagnetic member to achieve return movement is obtained. Where repulsion action or pulsed ferromagnetic action as above described is employed riod may be adjusted in the case in which the invention is applied to actuate an internal combustion engine valve.

Where the invention is applied to the actuation of a valve controlling fluid under pressure, return action may be effected either wholly or in part, by utilising the fluid pressure, control of the duration of opening being then achieved by controlling the effective pressure or the strength of the go impulse, or both.

A number of methods of impulse adjustment are available. One is to adjust the potential to which the condenser is charged. Another is to adjust the ohmic resistance in the discharge circuit. Both these methods, which may be employed singly or together, may be termed external adjustment methods since they do not involve alterations of the inductance value of the impeller coil or the capacity value of the condenser. It will be noted that adjustment of the ohmic resistance in the discharge circuit produces adjustment of the time constant and damping of the discharge circuit, increasing the time constant (and therefore decreasing acceleration) as resistance is increased. In addition adjustment may be effected by adjusting the value of the condenser and/or the inductance value. These adjustments will alter the rate of action by altering the frequency of the damped wave train produced when the condenser is discharged.

The invention is illustrated in the accompanying simplified and diagrammatic drawings in which Figure 1 illustrates a power press or like actuating mechanism in accordance with the invention employing repulsion drive in one direction and pulsed electro-magnetic drive for the return motion, while the remaining figures illustrate the application of the invention to internal combustion engine valve operation.

Referring to Figure l, the member to be moved is represented schematically by the shaft I which is required to be moved over short distance at very high speed in the direction of the full line arrow and returned in the direction of the broken line arrow. The former movement is obtained by means of a non-ferromagnetic repulsion member 2, e. g., a thick disc of copper and nielatrer-by means o "sierra=magrienc iiine 35 t e arts nd 3 both heing on=the-sh'aft'li T e repulsion member 2 is-closelyl-'adjacent-one side crarepuision coil and; the phihgc'r 3 is Y in c'o-ope tive'relation with the anathema-solenoid 5-: Rapid movement-or the repulsionmom beriti the direction of the full 'lin'e arrow i's ob ta-ihed? by Suddenly discharging the condenser ii Iii-Figural this is efi'eeted-b closing thecontabt's 'i'of a" re1ay"'W-hoSe'Winding s e'herg' ised' from a convenileh'fi sdurcerepresenh a-battery- 9 throu h the Contact segment In-andb'r -ush 1 t of a cominutett or I Z W-Hich isrotatedin the direction of the 'curved 'arroW"-head-:- Whenthe coil ms energised by the discharge pulse "from condenser Ftheinenibe'r 2 moveswery=sharp1ytothe left in the figure 'and' when a predeter'rninedtrave1 has oc'c'urred the member 3 closes-"contacts I 3 thii'seneig i'sing the winding M cca-rainy whose contacts are-iridica ted a-t I5 -frdm acon'veniem source represented bi -battery I The energisa ticn of coil l i 'clo'ses c'o'r'itacts iB a-nd thus-coin plete's a discharge c'ircuit forthe condenser i through the coil 5-," which is accordingly pulse energised and appliesa return-force to the mem be! 3.

The condensers 6 and I may be charged in ni'ent manner well knownper se. As showh;- amains source connected atterm'inals F8 feeds" through a step-up transformer l s an 'o'rdinary discharge tube rectifier'unit- Ed -from which un'smooth'ed D. CI is taken: tothe condensers 6 and l k- In order to preventexcessive current flowing through the windings- 6f the transformer I9 and possible damagetothe rectifier tube at 2-0 =when the condenser-s 6 and 1 1 are discharged for the discharge circuits are of low oh'mic r'esist'ancesit' is preferable to protect-the chargingcircuitsl- In the fie iire s'uch-protection is provided: by iric'ludirigg-ih series with the primary or transformer 1 9; normally closed 'relay' contacts 2 l 22*, arranged to be opened when their re'-' spective relay windings '-2-3,-24='areenergised. The relay-coil '23 is ener ised just priorto energisation of relay coi-LB by means of arr additional brush 25 on the commutator F2, whilecoil- 24' is energised- -just-prior to coil P4 by-means--ofan additional pair of contacts 26 actuated by memher .3 when moving in": the-direction orthe full line arrow. In general; the relay 22 -2 t-andas sociated circuit will not berequiied; since the circuit of coil 5 -will usually'not 'be-ofsuch low resistance astorcqui'reth'e provisiomofprotection for the apparatus- 18 20; b'utsu'chmrotection' is shown in Figure 1 forthe sake of coinpleteness.

A device as illustrated in Figure-T is well adapted-wfor power press operation and great forces. are obtainable comparativel easily. In one experimental press the repulsion coil had an outside diameter of 3", an insidediameter of 0.5. ZJIIdYQhthiGkIiBSS-Of 0.5" andconsisted of 1 80 -turns of No. 18 3: WI G- enamelled cotton covered: wire; The 'face adjacent: the repulsion member was covered fwith stainless steel sheet of, No'. 22 :gauge. i The: said repulsion:- member was-a disc of aluminium 3"! in diameter and 0.25 thick and was: fixed to a centralzaluminium shaft 1- in diameter and 3 long=v which continued int'oa mild steel shait also 1', indiameterand 2-1 long.- A light spring round thefal-uminium shaft held the repulsion member-against vthe steel, facing of the-repulsion coil-. Thecpress'die was mounted ontheend-otthe steel shafit; which passed; through a steel} guidev block, 5 the said die 6.7 fitting; some and: of tife strokeg 'into aa hardened steel'block bored' t receiveiit." The return so'lenoid was mounted: A justabove? the steel guide block'an'd consisted of- 4001) turns of 32 S.:W. Ga enameued silk covered wirehn'iaking a coil of ahout tf 'outs'ide diameter; 1 .5 inside diameter and-1 .5" thick.

The-condenser-from the repulsion coil was pulsed was of 50 midsaand charged toAOOO volts; On discharge the resultantrepulsion force produced on: the repulsion member was-about :5 tons;- so that the-diepenetrated metal placed just beneath it and. above thed'ie block. The' discharge occurred in about /1000 Part of a second; The same condenser-wastemploye'd both tolpulse the repulsio'n coil and: the return solenoid; but for operating thelatter it was charged only .to 1500 volts. About a quarter ofa second after operation of the repulsion member the condenser (at 1500- volts)' was discharged throu'gh'the re= turn solenoid which; acting on thewsteel shaft portion; drew up the die stripping it from" the metal it had penetrated during the repulsion stroke; The second, or return pulse lasted about /5 of' a second. Thus the-repulsion pulse took about 400 joules of energy and the return stroke nearly 62 joules, so that about 462 watt-seconds was taken from the electrical energy source. Since; in the case of the repulsion coil 400 joules are released in /m l see. the electrical power available for that period was 400 kW. and, taking the" conversion efficiency to mechanical energiyat about: 8%., as in pra'ctic'e it is; this givesaloout :43 'H P;

Figure 2 shows diagrammatically an embo'dimentof the invention as appliedto" the actuation of a Diesel engine fuel injection valve.

InFigure 2 a repulsion member thin the form ofadisc of aluminium,- copper, silver or other high" conductivity metal is mounted in a cylinder, 2?: formed'in effect, as an enlargement in the run of a fuel oil supply tube 28,29 made of stainless steel or other material of low conduce tivity and 'permeabilityand is attached to a hollow stainless steel or similar spindle 30 lying in thetube emerging from one flat face of the cylinder; The impulse member has a central hole leading to the hollowinterior of the spindle; the walls of which are formed with a port or ports- 3 i for the passage of oil. At its far end (not shown) the spindle-is formed as a needle valve (not shown) controlling oil injection. Positionedabout. the tube as in whichthe spindle lies and-close up against the adjacent flat face of the cylinder is-an impeller coil 4 connected through contacts l and, if desired, an-adjustable resistance (not shown), across a continuously charged condenser; The charging circuit is not shown in Figure 2. When the contacts -I are closed-l the condcnsertdischarges through the coild and the repulsion member 2' ismoved very rapidly to'the left inFi'gure 2 to open the needle valve.-

InF'igu-re 2 return movement is also obtained by repulsion action, a second coil 4' being; mountediabout the tube 28 projecting from the other side of the cylinder and this coil being connected (againaif' desiredthroughan adjustable resistance notshown) across a second continuously charged condenser 6', this circuit includingv contacts -'l-' arranged to be closed'a predetermined and, where required,- variable time after closure of. the contacts Tin the circuit of the-first corrdenser'li.

A-.modifiedarrangement-1 in which spring. controlled return action is obtained is shown in Figure 3. Here a spring 32, which may be adjustable if desired, is mounted in the cylinder 21 to oppose the motion of the repulsion member 2 when the condenser 6 is discharged, the second coil 4 and associated condenser circuit of Figure 2 being of course dispensedwith. In Figure 3 an adjustable resistance 33 is shown in series with the coil 4.

Instead of spring or repulsion return, magnetic return action may be obtained, for example as shown in Figure 4, by mounting a sleeve 3 of ferromagnetic material on the spindle and providing a co-operating magnetic coil 5' outside the appropriate part of the tube 29. This coil may be fed from a local source 34 through a rheostat 35 by which the return magnetic pull may be adjusted. Thus, by adjusting the current through the magnetic coil 5' the travel of the repulsion member, for a given discharge impulse, can be adjusted, thus adjusting the length of time the valve is open. Alternatively, however, electro-magnetic return by pulse energising the coil from a condenser discharge circuit after the manner of the coil 5 and associated condenser H and contacts I5 of Figure 1 may be employed.

In general it is preferred, though by no means necessary, to employ impeller coils of fiat pancake type, i. e., in which the coil diameter is greater than its length, rather than long, small diameter coils since the efliciency (ratio of change of kinetic energy of the repulsion member to change of energy charge in the condenser) is higher with the former type of coil. There is, however, a wide range of designs which can be adopted for the repulsion coil and repulsion member. Thus, as shown in Figure 5, the coil 4 can be solenoidal in form with a ring or disc 2 projecting about of its length into the coil or a fiat disc or ring repulsion member may rest against the side face of the repulsion coil as shown in Figures 1 to 4, or as shown in Figure 6 the repulsion member may be in the form of a truncated cone and the side face of the coil 4 correspondingly coned over about half the coil length to receive the repulsion member;

In arrangements in accordance with this invention in which very large currents flow in a repulsion coil for very short periods of time, i. e. when large capacity condensers charged to high voltage are employed in conjunction with repulsion coils of relatively few turns and low inductance, it is of advantage to employ so-called wave Wound coils as well known per se. This assists in giving quiet operation by avoiding sudden inter-turn movements in the coil itself when the discharge current fiows through it.

In the embodiments so far described and illustrated the repulsion member has been presumed movable and the impeller coil or coils fixed. Obviously this is not essential since, the repulsive force being relative, the repulsion member or the impeller coil or both may be movable. In one embodiment of this nature illustrated in Figure '7 a repulsion member 2 is mounted on the end of push rod 36, for example, of stainless steel, (or any other suitable non-magnetic low conductivity material) which actuates a fuel valve (not shown) and slides endwise in a hearing 31 mounted in a tube 38, which may also be of stainless steel. This tube is fitted axially into a cylinder 39 closed at one end by a flat wall (through which the tube and push rod project as shown) and at the other by a piston-like member 40 slidable on the tube and formed of suitable hollow section on its outer side to accommodate an impeller coil 4 which is fitted thereto. The tube is formed with ports 41 leading into the cylinder near the fiat face and fuel oil is admitted to said cylinder via a non-return valve 42 from a suitable supply (not shown) under pressure. When an impulse is fed tothe impeller coil 4 the repulsion member 2 and the coil 4 (to which the piston 40 is attached) are accelerated in opposite directions, the former opening the fuel valve and the latter providing a pump action to force oil through the tube and the now open fuel valve. After the impulse the oil pressure returns the coil to its initial position and the repulsion member is also returned by any of the methods already described. The repulsion member may be enclosed in a housing 43 fitted with a pipe 44 leading to a fuel oil pump (not shown) so that any oil which may seep through the push-rod bearing is returned. If desired, the piston 48 may be spring-biased to its initial position (that shown) so that, after an impulse, it is spring-returned and so sucks up oil into the cylinder 39 through valve 42. In this case the design may be made such that the fuel oil need not be supplied under pressure.

Where magnetic return of the repulsion member by a continuously energised magnet coil (as in Figure 4) is utilised in the case of employment of the invention for fuel injection in Diesel engines automatic control may be obtained by supplying constant amplitude pulses to the impeller coil and controlling the open period of the fuel valve by controlling the magnet coil current. The weaker the magnet coil current the longer will the valve stay open for a given impulse. Figure 8 shows an arrangement of this nature. Here a rheostat 35 in the circuit of the magnet coil 5' is utilised in effect as a throttle control causing more oil to be injected and the engine to speed up if the resistance provided by 35 is increased. The voltage for the magnet coil 5 is varied in dependence upon engine speedas shown it is derived from a small low voltage D. C. generator 45 driven by the engine-and a governed throttle action is thereby obtained, for if the load on the engine falls away causing an increase in speed, the voltage across the magnet coil circuit will increase, reducing the open period of the valve and thus counteracting the speed increase.

To increase the degree of control obtained it is preferred to provide in the circuit of the impeller coil 4 a second variable resistance 46, unicontrolled in opposite sense to that of the variable resistance in the magnet coil circuit, so that a resistance variation at 35 which increases the magnet coil current is accompanied by a resistance variation at 46 which decreases the impeller coil current and vice versa. The remainder of Figure 8 will be described later herein.

In Figure l the condenser discharge circuits are shown controlled by relay actuated contacts and in the remaining, highly simplified diagrammatic Figures 2 to 7 the discharge circuit control means are represented simply by switch contacts without operating means therefor being shown. The necessary control of the condenser discharge circuits of apparatus in accordance with this invention can, however, be effected in any of a variety of different ways, either by mechanically operated switches, i. e., switches operated by cams or the like or commutator switches; or,"as shown in Figure 1, by switches constituted by the contacts of relays; or,..purely electrically,by switches constituted by electronic devices such asT-hyratrons which can be changed from'the conductive to the non-conductive condition in manner well known per se by the application of control potential thereto. Electronic switch control is well suited to cases in Which accurate timing is required, e. g.,where the invention is applied. to Diesel engine fuel injection valve control. Thus, referring again to Figure 8' the impeller coil 4 and adjustable resistance 46 are in series with the anode-cathode space of a gaseous electronic discharge tube (so-called Thyratron) 4! across the condenser 6. The magnet coil 5', in series with its adjustable resistance 35, is connected to the terminals of the engine driven low voltage dynamo45 as already described. The engine also drives a high voltage dynamo 48 which charges the condenser 6 through a suitableresistance 49. The Thyratron cathode is heated by the usual heater, which may be energised by the normally provided starter battery 55 and the'Thyratron grid circuit comprises a grid negative bias source 5! in series with an inductor coil 52. The anode of "the Thyratron is connected, through the resistance 46 and coil 4, to the same side of the condenser 6 as that to which the positive "terminal of the high voltage dynamo 48 is connected (through resistance), so tha't'the said Thyratron receives anode potential from this dynamo though this is, of course, not a necessary arrangement. Normally the Thyratron is non-conductive but when a suitable voltage impulse is induced in the inductor coil 52 (the method of timing and inducing this impulse will be described later) ,the negative bias from the source 5| .is overcome, the Thyratron flashes 'over and the impeller coil 4 almost instantly receives a discharge surge from the condenser E.

Gonsider the operation of this arrangement. Assoon as the engine is rotated by the starter motor 53 byclosure of the starter switch 54 'the low-voltage dynamo 45' provides current for the magnetic .coil 5 and the condenser 55 charges fromthe high voltage dynamo-48. At the corroot-moment :in the engine piston travel, the inductor coil 52 receivesa voltageimpulse (as will be described later), the Thyratron 41 breaks down, the impeller coil 4 receives a discharge whichoperates the repulsion member (not shown in Figure 8) and oil is injected into the cylinder so that the engine fires. At this time the engine is still rotating quite slowly. The circuit parameters and, in-particular, the time constant (if the condenser charging circuit and the voltage-speed characteristic of the high voltage dynamo 4B are so chosen that at this time the condenser voltage, though high enough to operate the repulsion member, is still comparatively low. The engine speeds up but, owing to the precalculated circuit constants .the rate of charge of the condenser isstill greater than the effective rate "of discharge'with firing so that the impeller coil impulses increase with engine speed. This increase is, however, counter-balanced by the simultaneous increase in the magnetic coil current due tothe increase in the voltage of the engine=driven low voltage dynamo 45. Thus, duringthe initial acceleration periodthe amount of oil injected will be substantially constant. When-a certain speed has been reached, however, the condenser 6 reaches a maximum voltage and however much faster theengine triesto fire, this voltage will not increase for the reason that, although with increased engine speed the potential from the high voltage dynamo 48 increases, the time constant of the condenser chargingcircuit ensures that the condenser voltage 'lags' bee hind, discharge occurring before the'condenser voltage exceeds the predetermined maximum. Accordingly, once a certain speed has been attained'the condenser 6 always discharges at a constant voltage, giving a constant impeller coil impulse. The 'magnetic coil current, however, increases with speed so that an automatic governor action is obtained, the engine maintaining a substantially steady and constant speed determined-by the setting-0f the throttle constituted by thedifferentially controlled magnetic coil and impeller coil resistances 35, 56. Thus, above a "minimum speed, loadyariations produce magnetic coil current variations "which are not counter-balanced by impellercoil 'cur rent variations and the fuel injection is automatically varied to maintain a throttle-setsp'eed despite such load variations.

There are numerous difierent ways in which the required triggering of the Thyratron and therefore the timing of the valve actuation may be effected. For example, as shown in Figure 9, a small magnet55 may be mounted on a suitable insulating disc 56 on the engine shaft' so that, as the engine rotates this magnet passes :close under the inductor coil 52 (ar separate coil coupled thereto or connected therewith) thereby to inducethe required triggering voltage; or as shown in Figure '10 'the insul'ating disc fifim'ay carry a small conductive plate i5! which passes beneath and'so-electrostatically couples two fixed conductive plates 58 in the 'Thyratrongr'id fellcuit thereby triggeringthe Thyratron by capacity change; or the disc may act after the manner of a commutator or may be arranged to actuate a :switch which triggers the Thyratron or discharges the condenserdirect. The use of direct conductive discharge of the condenser is not preferred, despiteits electrical simplicity, because it-gi-ves slightly le'ss'accurate timingand involves putting high voltages on engine parts.

Timing adjustment may be effected, foraexample by adjustablymountingthe inductor coil, the capacity plates, or the commutator brushor switch (as the case may be) or by adjusting the bias 'onthe Thyratron (if one is employed) and arranging it to be'triggered before :the maximum attainable triggering voltageis reached.

'lf desired a gas rectifier may be connected-in reverse across the Thyratron. If this bedone the fulldischarge'of the condenser will' pass through the impeller coilinstead of only the first positive peak of the condenser .oscillatorydischarge.

In another-embodiment illustrated in Figure 'll landemploying two impeller coils '4, 4','one for opening the valve-and the other for closing it, the-opening coil disconnected in series with the discharge spaceof'a Thyratrond'l' across an adjustable condenser 6 and the closing "coil'd' is connected' through a gas discharge rectifier '59 across the'same condenser, the 'ca'thode' of the Thyratron and the anode of the'rectifier being connected togetherand to the negative potential of the charging source (not shown) whose positive terminal is connected to the 'remaining lterminal of the condenser. The Thyratroniis biased to the fclosed "condition by potential applied :to its grid over lead fifl and is arranged, forexample asiabove described, to receive a triggering g-pulse on its grid at-the moment of fire. This circuit arrangement .is obviously of oscillatory :nature and (providedthe Q value is fairly high, i. -:e.,

there is not too much resistance) the discharge of the condenser 6' will be of the damped wave train type. Clearly the Thyratron 41 can open, i. e., pass current only when there is positive potential on its anode and simultaneously a triggering potential on its grid. Therefore, owing to the charge polarity of the condenser, current will fiow through the opening coil 4 (when the Thyratron is triggered) only during the first half cycle of oscillatory discharge, and, during this half cycle, the rectifier 59 will be closed. On the next half cycle, however, the Thyratron closes and the rectifier opens giving a discharge pulse through the closing impeller coil 4. Thus one-half of the first cycle opens the valve and the next half closes it. The interval between opening and closing depends on the natural frequency of the circuit which can, of course, be adjusted by adjusting the inductance or the capacity or both. The third half cycle-is obviously ineffective to produce an impeller coil pulse because the rectifier now'has a negative anode and the triggering pulse has ceased on the Thyratron.

Clearly since the interval between opening and closing of the fuel valve depends on thecircuit frequency, control of inductance or capacity (the latter is more convenient) will control the amount of fuel injection and either inductance or capacity adjustment,'or both if differentially arranged, may be u'sedto produce theeffect of a throttle, and if desired, an automatic throttle operating to maintain substantially constant governed speed despite engine load variations. For example the adjustable condenser 6' of Figure 11 may be controlled in dependence upon engine speed, of course decreasing incapacity with increase in speed. A convenient centrifugal condenser suitable'for use for this purpose is illustrated in mutually perpendicular views in Figures 12 and 13 and comprises an insulating disc 6| driven by the engine and carrying two concen tric metal cylinders 62, 53 having their common axis on the axis of rotation. The outer cylinder carries by means of radial springs 64 a number (say four) arcuate plates 65 which cooperate with the inner cylinder 62 to constitute the condenser 6 of Figure 11 to which connection ismade b y brushes 66. As the speed of rotation increases the springs are compressed'by the increasing centrifugal force on the arcuate plates, the spacing between the plates andthe inner cylinder increases and the capacity falls. Such a condenser may constitute the main or throttle condenser 6' of Figure 11 or it may be an auxiliary condenser in parallel therewith.

For simplicit in description there has been so far noreference to multi-cylinder engines but obviously the invention is applicable thereto, either'by providing a separate discharge condenser for each cylinder or a common condenser and a suitable distributor arrangement. For example in a four cylinder engine there might be provided as shown in Figure 14 four high tension dynamos c8 driven by the engine, each charging its own condenser 6 through a resistance 4'9 and each condenser being arranged to be discharged by its own Thyratron 4T, triggered in the manner already described each by its own triggering inductor coil 52. The inductor coils are arranged round a disc 56 having a magnet 55 thereon and rotated by the engine. A common bias source may be provided for all Thyratrons. In a modification illustrated in Figure 15 the condensers 6 are charged each through a separate rectifier 51 from a separate secondary 68 of a multiwinding transformer having a primar 69 energised from an A. C. machine 48' driven by the engine. Or, again, instead of using a plurality of charging dynamos, one for each cylinder, a composite machine comprising a common rotor and four stators or a common stator and four rotors could be used. Yet, again, as shown in Figure 16 the four condensers 5 could be arranged in series as respects a common charging circuit constituted by a large main condenser 1!], which is continuously charged from a suitable source (not shown) through a resistance H, and a switch member driven by the engine. This member carries a magnet 55 for inducing voltages in the four Thyratron-triggering inductor coils 52, as before, and also carries a contact co-operating with a brush 12 which, once per revolution of the engine, connects the positive terminal of the main condenser 10 to the positive side of the group of four series connected discharge condensers 6, the negative side of the main condenser being directly connected to the negative side of said series group.

In an arrangement shown in Figure 17 in which only a single condenser E is employed for a multi-cylinder engine the condenser is connected through a main Thyratron 41 across a suitable voltage source (not shown) so as to be charged thereby once per revolution of the en gine, this being effected by triggering the Thyratron to conductivity in any suitable convenient way (not shown). Connected across this'condenser are four circuits (assuming a'four cylinder engine) each comprising a Thyratron 41" in series with a resistance 49 and an impeller coil 52. The Thyratrons 41" are alternately reversed, i. e., the first has its anode connected to the one line, the second has its cathode connected thereto, and so on. The four resistances are of diiferent values, that in the circuit of the first of the Thyratrons 41 being largest, that in the second the next largest, and so on. The four Thyratrons 4'!" are arranged to be triggered at the proper times in any suitable way (not shown) When the first of these Thyratrons is triggered it passes current for the first positive half cycle of the oscillatory main discharge, i. e., until its anode goes negative. When the next Thyratron is triggered it passes current for the next (nega-- tive) half wave of discharge since it is reversed with reference to the first Thyratron. Thus four successive half waves of. discharge produce four impulses, one for each impeller coil. Thefour resistances 49 are of successively decreasing valuses so as to ensure that the four discharges shall be of equal amplitude despite that the state of charge of the condenser is reduced by each successive discharge of the sequence of four. Alternatively, though not preferably, four different sized impeller coils may be used so that unlike pulses may produce like fuel injections.

The invention is obviously capableof numerous difierent'variations not described herein and. is by no means limited to applications nor to the embodiments described. For example where-the invention is applied to Diesel engine fuel injector operation timing of fuel injection may be efiected not by a member driven 'bythe engine crank shaft but by a member or membersin the engine cylinder or cylinders. Thus a carbon pack resistance may be exposed to cylinder pressure and ar-' ranged to trigger a Thyratron for fuel injection when that pressure reaches a, predetermined value or a piezo-electric crystal may be similarly exposed to cylinder pressure and employed as a triggering agency; or a pair of insulated conductors may be suitably arranged in the cylinder so as to constitute two plates of a, three plate condenser of which the piston is the third plate, triggering being brought about when the piston is in a pre-determined position with relation to the two conductors, thus producing pre-determined capacity; or a variable capacity constructed after the manner of an electrostatic microphone may be mounted in the cylinder with its diaphragm subjected to cylinder pressure, said capacity being arranged to act as a triggering agency when its capacity reaches a value corresponding to a pre-determined cylinder pressure.

.Again, where desired, known methods'of governing control may be employed in combination with methods of this invention. Thus, where an adjustable resistance, or inductance or capacity is so arranged as to act, in effect, as a throttle, it may be subjected to automatic adjustment by a centrifugal governor.

What I claim is:

1. Electro-mechanical high speed gear comprising in combination electrical energystorage means, a charging circuit therefor, a pulse dis- .charge circuit, means for discharging energy from said storage means into said discharge circuit in a sharp pulse of current a repulsion coil in said discharge circuit, an electrically conductive non-ferro-magnetic repulsion member adjacent said repulsion coil, a member to be moved, and means utilizing the rapid accelerating repulsion force set up between said repulsion coil and said repulsion member when the discharge currentpulse occurs for moving said member to be moved.

2. Electro-mechanical high speed gear comprising in. combination a condenser, a charging circuit therefor, a pulse discharge circuit therefor, said discharge circuit including circuit completing means and a repulsion coil and having resistive damning below the critical value whereby a sharp pulse of discharge current is produced when said discharge circuitls completed, an electrically conductive non-ferro-magnetic repulsion member adjacent said, repulsion coil, a member to be moved, and means utilizing the rapid accelerating repulsion force set up between said repulsion coil and said repulsion member when the discharge current pulse occurs for moving said member to be moved.

3. Electro-mechanical high speed gear com.- prising in combination electrical energy storage means, a charging circuit therefor, a discharge circuit, means for discharging energy from said storage means into said discharge circuit, .a repulsion coil in said discharge circuit, an electrically conductive non-ferro-magnetic repulsion member adjacent said repulsion coil, a member to-be moved, means utilizing the repulsion force set up between said repulsion coil and said repulsion member when the discharge occurs for moving said member to be moved, a ferro-magne'tic member mechanically connected to the member to be moved, a magnet coil adjacent said ferromagnetic member and an energizing circuit for said magnet coil to impart return movement to the ferro-magnetic member.

l. Electro-mechanical high speed gear comprising in combination a condenser, a charging circuit therefor, a discharge circuit therefor, said discharge circuit including circuit completing means and a repulsion coil and having resistive damping below the-critical value, an electrically conductive non ferro-m-agnetic repulsion :member adjacent-saidrepulsion coil, a member to be moved, means utilizing the repulsion force set up between said repulsion coil and said repulsion member when the discharge occurs for moving said member to be moved, a -ferro-magnetic member mechanicallyconnected to the member to be moved, a magnet coil adjacent said ferromagnetic member and an energizing circuit for saidmagnet coil to impart return-movement to the ferro-magnetic member.

5. Electro-meclranical high speed gear comprising in combination electrical energy storage means, a charging circuit therefor, a discharge circuit, means for discharging energy from said storage means into said discharge circuit, a repulsion coil in said discharge circuit, Ian electrically conductive non-ferroemagnetic repulsion member adjacent'said repulsion coil, a member to be moved, means utilizing the repulsion force set up between said repulsion coil and said repulsion member whe the discharge occurs for moving said member to ibe-moved,.a fer-ro-magnetic member mechanically connected to the member to be moved, a magnet coil adjacent said ferro-magnetic member and an energizing circuit for said magnet coil to impart return. movement to the 'ferro-magnetic member, said last mentioned circuit including a condenser, a charging means therefor anddischarge means therefor includin said magnet coil.

-6.-Electro-mechanical high speed gear com prising in combination a condenser, a charging circuit therefor a discharge circuit therefor, said discharge circuit including circuit completing means and arepul'sion coil and having resistive damping below the criticalvalue, an electrically conductive non-ferro-magnetic repulsion memberadjacent said repulsion coil, a member to be moved, means utilizing the repulsion. force set up between said repulsion coil and said repulsion member when the discharge occurs for moving said member to be moved, a ferro-magnetic member mechanically connected to the member to be moved, a magnet coil adjacent said ferro-mag netic-member and an energizing circuit for said magnet coil to impart return movement to ferromagnetic member, said last mentioned circuit including a'condenser, a charging means therefor and discharge means therefor including said magnet coil.

*7. Electro-mechanical high speed gear comprising in combination electrical energy storage means, a charging circuit therefor, a pulse dischargecircuit therefor, means for discharging energy'from'saidstorage means as a sharp pulse into said discharge circuit, a repulsion coil in said discharge circuit, an electrically conductive nonferro-magnetic repulsion member adjacent said repulsion coil, amember to be moved, means utilizing-the rapid accelerating repulsion force set up between said repulsion coil and said repulsion member when the -pulse discharge occurs for moving said member to be moved and a circuit closing device automatically actuated by the member to be moved.

8. Electro-mechanical high speed gear comprising in combination a condenser, a charging circuit therefor, a pulse discharge circuit therefor, said discharge circuit including circuit completing means and a repulsion coil and having resistive damping below the critical value whereby a sharp pulse of discharge current is produced when said discharge circuit is completed, an electricall conductive non-ferro-magnetic repulsion i i-ember adjacent said repulsion coil, a member to be moved, means utilizing the rapid accelerating repulsion force set up between said repulsion coil and said repulsion member when the discharge current pulse occurs for moving said member to be moved and a circuit closing device automatically actuated by the member to be moved.

9. Electro-mechanical high speed gear comprising in combination electrical energy storage means, a charging circuit therefor, a discharge circuit, means for discharging energy from said storage means into said discharge circuit, a wave wound repulsion coil in said discharge circuit, an electrically conductive non-ferro-magnetic repulsion member adjacent said repulsion coil, a member to be moved, and means utilizing the repulsion force set up between said repulsion coil and said repulsion member when the discharge occurs for moving said member to be moved.

10. Electro-mechanical high speed gear comprising in combination a condenser, a charging circuit therefor, a discharge circuit therefor, said discharge circuit including circuit completing means and a wave wound repulsion coil and having resistive damping below the critical value, an electrically conductive non-ferro-magnetic repulsion member adjacent said repulsion coil, 2. member to be moved and means utilizing the repulsion force set up between said repulsion coil and said repulsion member when the discharge occurs for moving said member to be moved.

ll. Electro-mechanical high speed gear comprising in combination electrical energy storage means, a charging circuit therefor, a pulse discharge circuit, means for discharging energy from said storage means as a sharp pulse into said discharge circuit, a repulsion coil in said discharge circuit, said discharge circuit also including controllable circuit closing means, an electricall conductive non-ferro-magnetic repulsion member adjacent said repulsion coil, a member to be moved, and means utilizing the repulsion force set up between said repulsion coil and said repulsion member when the pulse discharge occurs for moving said member to be moved.

12. Electro-mechanical high speed gear comprising in combination a condenser, a charging circuit therefor, a discharge circuit therefor, said discharge circuit including circuit completing means constituted by the anode-cathode space of a Thyratron having a control circuit and a repulsion coil and having resistive damping below the critical value, an electrically conductive nonferro-magnetic repulsion member adjacent said repulsion coil, a member to be moved and means utilizing the repulsion force set up between said repulsion coil and said repulsion member when the discharge occurs for moving said member to be moved.

13. Electro-mechanical high speed gear comprising'in combination electrical energy storage means, a charging circuit therefor, a pulse discharge circuit, means for discharging energy from said storage means as a sharp current pulse into said discharge circuit, a repulsion coil in said discharge circuit, said discharge circuit also including controllable circuit closing means constituted by the anode-cathode space of a Thyratron having a grid control circuit, an electrically conductive non-ferro-magnetic repulsion member adjacent said repulsion coil, 2. member to be moved, and means utilizing the repulsion force set up between said repulsion coil and said repulsion member when the pulse discharge occurs for moving said member to be moved.

14. Electro-mechanical high speed gear comprisng in combination electrical energy storage means, a pulse charging circuit therefor, a discharge circuit, means for discharging energy from said storage means as a sharp pulse into said discharge circuit, a repulsion coil in said discharge circuit, said discharge circuit also including controllable circuit closing means, circuit opening means in said charging circuit operable before operation of said circuit closing means, an electrically conductive non-ferro-magnetic repulsion member adjacent said repulsion coil, a member to be moved and means utilizing the repulsion force set up between said repulsion coil and said repulsion member when the pulse discharge occurs for moving said member to be moved.

15. In a power press electro-mechanical high speed gear comprising in combination electrical energy storage means, a charging circuit therefor, a discharge circuit, means for discharging energy from said storage means into said discharge circuit, a repulsion coil in said discharge circuit, an electrically conductive non-ferromagnetic repulsion member adjacent said repulsion coil, a ferro-magnetic member mechanically connected to said repulsion member, a press die driven by said ferro-magnetic member, a, magnet coil adjacent said ferro-magnetic member, a condenser, means for charging said condenser and circuit closing means actuated by movement of said ferro-magnetic member in the pressing direction for discharging said condenser through said magnet coil to return said ferromagnetic member.

JAN FORMAN.

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

UNITED STATES PATENTS Number Name Date 390,802 Patten Oct. 9, 1888 2,018,159 Walker et a1. Oct. 22, 1935 2,077,259 Planiol Apr. 13, 1937 2,086,913 Kelly July 13, 1937 2,363,753 Smith et a1 Nov. 28, 1944 2,425,767 Vang Aug. 19, 1947

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