US2966148A

US2966148A - Floating piston engines

Info

Publication number: US2966148A
Application number: US703428A
Authority: US
Inventors: Jarret Jacques Henri; Jarret Jean Marie Baptiste
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-12-18
Filing date: 1957-12-17
Publication date: 1960-12-27
Anticipated expiration: 1977-12-27

Description

Dec. 27, 1960 J. JARRET ET AL 2,966,148

FLOATING PISTON ENGINES Filed Dec. 17, 1957 4 SheetsSheet 1 5wrrcH CONTROL Qual- Mia.

Dec. 27, 1960 JARRET Er AL 2,966,148

FLOATING PISTON ENGINES Filed Dec. 1'7, 195'? 4 Sheets-Sheet 2 Dec. 27, 1960' J. H. JARRET ETAL 2,966,148

' FLOATING PISTON ENGINES Filed Dec. 17, 1957 4 Sheets-Sheet 3 PuLsE G EN ERATO R.

Dec. 27, 1960 J. H. JARRET ETAL 2,956,148

FLOATING PISTON ENGINES Filed Dec. 17, 1957 4 Sheets-Sheet 4 United States Patent FLOATING PISTON ENGINES Jacques Henri Jarret, 11 Rue des Chenes, Le Vesinet, France, and Jean Marie Baptiste Jarret, 18 Rue du Mont-Valerian, Saint-Cloud, France Filed Dec. 17, 1957, Ser. No. 703,428

Claims priority, application France Dec. 18, 1956 7 Claims. (Cl. 123-46) This invention relates to engines of the floating piston type and provides improved operating means for such engines especially in connection with starting, regulation, and synchronization between the pistons of such engines. its general object is to provide such means which will fulfill various practical requirements more completely than the means heretofore available.

The invention provides an arrangement for use with a floating-piston engine, which comprises at least one magnetic element rigidly connected with a piston of said engine, a magnetic circuit with respect to which said element is movable on reciprocation of the piston to modify the reluctance of said magnetic circuit, and ener gizable electric winding means inductively associated with said magnetic circuit and connected with an electric circuit, whereby a mutually coupled relationship is present between the variations in the kinetic energy of reciprocation of said element and piston, and variations in the electrical energy in said electric circuit, so that energy can be selectively transferred from said engine to said electric circuit and vice versa.

The arrangement is operable as a starting device for floating-piston engines, and in that case one or preferably a series of electric voltage pulses are applied to the electric windings, preferably alternately in one and the other of two windings associated with respective legs of a multi-legged core forming said magnetic circuit, each of said legs having a gap in which an associated movable magnetic element is movable, both movable elements being coupled for bodily reciprocation with the engine piston and being so associated with said respective legs of the magnetic circuit that the application of said pulses alternately to the two related windings will cause a bodily reciprocation of said movable elements and hence the piston coupled thereto, thereby starting the engine.

Where the invention is applied to the feed regulation of the floating piston engine, variations in an electrical characteristic of the current induced in one or more windings associated with the magnetic circuit may be used to operate a suitable relay device, such as a solenoid relay, which in turn may produce a mechanical displacement of a regulator control element such as an air or fuel intake valve. In connection with such a regulating system, the arrangement of the invention is able to provide a servo-loop or feedback action of extremely eflicient and advantageous character, as will be made apparent from the detailed disclosure hereinafter.

Where the invention is applied to the synchronization of a pair of conjugate floating pistons ina common ice cylinder of an engine, each piston may have an associated movable magnetic element mechanically connected with it, each element cooperating with a respective magnetic circuit, and means are provided for coupling both circuits in synchronizing relationship. Thus, the winding means associated with the respective magnetic circuits can be cross-connected into a balanced circuit so that in case of a lack of synchronization between the reciprocation of the two elements, energy will be transferred in one or the other sense over said balanced circuit to exert magnetic forces on said elements which will restore them to accurate synchronism.

Exemplary embodiments will now be described in detail by way of illustration but not of limitation and with reference to the accompanying drawings wherein:

Fig. 1 is a diagrammatic sectional view of one embodiment of the invention which is particularly suitable as a starting device for a free-floating piston engine, the section being taken along the line II of Fig. 2, as seen in the direction of arrows;

Fig. 2 is a section taken on the line IIII of Fig. 1, as seen in the direction of arrows;

Fig. 3 is a diagrammatic view of a part of a throttle regulating device constructed in accordance with one embodiment of the invention;

Fig. 4 is a diagrammatic view of an automatic injection regulating device constructed in accordance with another embodiment of the invention; and

Fig. 5 is a diagrammatic sectional view of a further embodiment of the invention as applied to the synchrom'zing of a pair of conjugate floating pistons.

The present invention will first be described with particular reference to its operation as a starting device as illustrated in Figs. 1 and 2. As there shown the engine comprises a cylinder 1 having a single floating piston 6 reciprocable therein but it will be understood that a single piston is shown only for the purpose of simplifying the disclosure.

Associated with the cylinder 1 are a spark plug or igniter 2, an intake port 3 (Fig. 1), an exhaust port 4 (Fig. 2) and a transfer or by-pass duct 5. It will be understood that the engine would normally comprise such fuel supply equipment as a carburetor or an injector, not shown.

The engine here shown is a two-stroke engine and its piston 6 is accordingly formed with a transfer or bypass port 7. As is characteristic for free-floating piston engines, the piston rod 8 has no connecting rod coupled with it for the transmission of movement.

Rigidly connected with the free end of piston rod 8 are two of spaced non-magnetic bar members 9a and 9b (Fig. 2) which are rigidly interconnected at their ends to form a frame. Secured to the end of said frame remote from the piston 6 is a device for ensuring a positive return of the piston 6 at its outer dead centre position. Such device is conventional and is here shown as comprising a piston 10 reciprocating in a chamber 21 constituting an auto-compressor device.

The electromagnetic section of the system in the illustrated embodiment comprises a magnetic circuit in the form of a core having two side legs 11a and 11b and a central leg 12, all three legs being interconnected by transverse end legs 13a and 13b. The central leg 12 is here shown solid but itwill be understood that the present invention may advantageously be combined with a system according to the applicants prior U.S. Patent No. 2,829,276 wherein an electromagnetic system somewhat similar to that of the present application is used for converting the reciprocation of a floating piston engine to a rotational movement, and in such case the core leg 12 may be formed with a cutout for receiving a rotatable armature of a repulsion type motor therein, the ends of said leg directed towards the armature serving as magnetic pole pieces for the repulsion type motor.

In the embodiment described the side legs 11a and 11b are formed with aligned transverse cutouts which provide relatively wide airgaps 11a, Lib in each side leg, so that such airgaps insert high reluetanees into the associated branches of'the magnetic circuit,- the increase in reluctance'being at least 100% of its-initial value, and preferably exceeding said initial value by a factor of about from 5 to 20.

Freely reciproeable together with frame 9a, 9b in said airgaps 11a, 11b with just enough clearance to avoid friction are two movable magnetic elements 14a and 14b which are preferably vane shaped and of such dimensions in a direction transverse to the legs 11a and 111; as to substantially fill the airgaps 11a, 11b'. The spaced vanes 14a and 14b are mounted within the frame formed by the nonmagnetic members, 9a and 9b at relative positions such that when one of the vanes is positioned in its airgap in registering relation with the side leg 11a or 11b, respectively the other vane is completely clear of the airgap in the other side leg and is positioned outside the magnetic core.

Wound about the side legs 11a and 11b are the coils or windings 15a, 15b, respectively. Depending on the particular use to which the system is to be put, the windings 15a and 15b are arranged to be energized from a D.-C. source 16 one at a time or to be energized simultaneously from the source 16, in series or in parallel. For the purpose of selectively disconnecting and connecting the windings 15a, 15b from and to each other there is provided a jack or another type of coupler device schematically indicated at 16c and having its terminals connected with the source terminals. A double-pole double-throw switch 16d makes it possible, in the open-circuit condition of the coupler, to selectively energize one or the other of the two windings, as will be readily understood upon observation of the connections shown, which include, lines 162 connecting the source 16 to the coupler and to the switch, and the lines 16a and 16b connecting the windings 15a and 15b to the opposite switch and coupler, terminals.

In the instant embodiment the windings 15a and 15b are wound with such polarities that. they tend to generate, when energized, magnetic fluxes of suitable polarities in the central core leg 12 as will presently appear.

The electro-magnetic section now being described, with reference to Figs. 1 and 2 isapplicable, according to the invention, also for purposes other than the starting of the engine, e.g. for automatic regulation of air and/or fuel supply and for synchronization of the pistons in a twinpiston engine. While the latter applications will be more specifically described hereinafter with referenceto Figs. 3 to 5,'it may be noted at this point that, when the electromagnetic section is utilized as a regulator or as a synchronizingmeans, the windings 15a and 15b are wound in such a way as to generate magnetic fluxes of opposed polarities through the central leg 12. Furthermore,

'for certain applications an additional winding 17 may be provided on the central leg as will later appear, but tlus winding 17 is not used when the system performs an engine-starting function. a

v The electromagnetic section including the core, and windings thereon is enclosed in a casing 19 and is secured theretoby suitablebolts or cross members 29.

The system described is operated as follows for starting 7 a floating-piston engine. Assuming that. a current p e of suitable polarity is supplied to one of the windings say 15a, a magnetic flux is created in the associated side leg 11a developing an attractive force which causes the movable element 14a to be drawn inwards of its airgap 1111:, thereby causing, from the position shown as well as from an extreme left position, a rightward bodily displacement of the rigid assembly including 9a, 9!; piston rod 8, piston 6, and the other core element 14b. Thereafter, another current pulse supplied to the winding 15b will shift the other element 14b leftward and cause a leftward bodily displacement: of the assembly including the piston. Hence the delivery of a current pulse to one of the windings 15a, 15b and preferably an alternate application of pulses to both windings 15a, 15b, will result in reciprocating the piston 6 in the cylinder thereby providing a means of starting the engine. Advantageously the rate of alternate application of voltage pulses to the windings 15a and 15b is initially slow and is gradually increased while the duration of the pulses may 'be decreased, through any convenient means F capable of e.g. moving the contact arms of change-over switch 16d alternatingly between its alternative circuit-closing positions, at a predetermined gradually increasing rate thereby providing a highly efficient and reliable starting action; it will be understood that means (not shown) would be provided for injecting the fuel and/or igniting the fuelair mixture at the proper times in correlation with the rate of application of the electric voltage pulses to the windings.

The timing of application of the pulses to the alternate windings may be determined in any of various ways. Thus a simple switch such. as that shown at 16d may be used, or a device having an equivalent effect. Preferably delay means, not shown, are interposed in the circuits of the windings and the delay time may be made automatically adjustable to provide an optimum timing of the alternate pulses, particularly the gradually increasing rate of pulse delivery men-tioned above. The most suitable actual duration of time lapse between the pulses and the amplitude thereof would naturally depend on the characteristics of the engine, such as nominal power output and speed and length of piston stroke. The source 16 may be provided by a storage battery or other convenient generator.

We shall now describe an embodiment of our invention as applied specifically to the fuel supply regulation of floating-piston engines. The problem here is that of automatically controlling the setting of some control such as a, valve, which acts e.g. on the rate of supply of combustible mixture to the cylinder or cylinders, in response to some operating factor of the engine such as the engine speed or load, and this is accomplished according to the invention by operating said control in response to varia tions in the electrical energy'put out by a part of the electromagnetic circuit. It is especially advantageous to combine this application of the present invention with the electromagnetic drive system of applicants aforementioned patent for converting the reciprocation of floating pistons into rotary motion, including means for varying the drive ratio.

Whereas in the first embodiment of this invention relating to the starting of an engine voltagewas alternately supply -to each of two windings of the system in order to reciprocate the air of magnetic elements connected with the engine piston, in the application of the invention to an engine regulator system use is made of the electric output i.e. the amperage, the voltage or the frequency of a current induced in a windingof the electromagnetic system in response to the reciprocation of said movable magnetic elements due to the driving action of the piston 6 in the two-stroke engine operating in normal manner. Excitation means must therefore be provided and this may be done in any of various ways. However, in view of the desirability of combining this system both with the drive system disclosed in the aforementioned patent and/or with the starting device described herein with reference to Figs. 1 and 2, it is convenient to use the afore-mentioned windings 15a, 15b of the system of Figs. 1 and 2 as excitation windings, said windings in that case being preferably coupled together by means of coupler 160. Thus, after first having started the engine with coupler 160 in open-circuit condition, the coupler would then be moved to closed condition (while switch 16d is held open) so that the same system thereafter performs the regulating function. In this case, the jack 16c in closed position connects both windings 15a and 15b in parallel with the source 16 so that the legs 11a and 11b are magnetized. The alternating movement of the members 14a and 1412 into and out of the respective gaps 11a and 11b periodically increases and decreases the magnetic flux in 11a and 11b, respectively, whereby magnetic pulsations are created in the center leg 12, and consequently corresponding electric pulses are induced in the winding 17 surrounding the leg 12. The result is an alternating current output at the terminals 18 and applicable to an electro-mechanical device C referred to below and controlling the engine intake.

In using the system of the invention to regulate the operation of the engine the fuel or/ and air supply to the engine may be regulated in response to any desired electrical characteristic of the output electrical energy, including the frequency, voltage, current or phase condition.

In one form, wherein the frequency of the output energy is used, the engine intake may be regulated in a manner to maintain the reciprocation rate, and hence the mean effective velocity, of the pistons substantially constant, while the engine output is allowed to vary over the full range from zero to a prescribed nominal load. For this purpose an air or fuel intake control valve (arranged at D between the device C and the intake port 3) may be operated at C by way of a conventional electromechanical relay device responsive to frequency variations in the output voltage, so that any departure of the frequency from a prescribed value will result in altering the setting of the valve through said relay in such a sense as to return the engine velocity to normal, i.e. increase the fuel supply in case of a drop in piston velocity and output voltage frequency, and reduce the supply in case of a rise in piston velocity and voltage frequency. The auxiliary electromechanical relay device may comprise a conventional sliding-core solenoid device e.g. that of Fig. 4 energized by way of a frequency sensitive circuit which may contain a conventional discriminator capable of varying its output voltage in response to frequency variations.

In another form of regulating system according to the invention the engine intake is varied in such a manner as to maintain the output of the engine constant under varying load. In such a type of system there may be provided in addition to the energizing or primary winding or windings 15a and 1512, one or more secondary windings, in which a current is induced which will vary as a function of the load because a change in load will change the speed and frequency of the piston 6. The secondary Winding may constitute the winding 17 shown in Fig. l and the electromagnetic system will then operate somewhat in the manner of a static alternator producing an A.-C. output across the pair of terminals 18 (Fig. 1). Alternatively, the secondary winding means may comprise the winding of a rotor operated as an electric motor in the manner disclosed in our US. Patent No. 2,829,276. In any case the varying voltage from the secondary winding 17 may be used to energize a slidingcore solenoid relay device of the type above referred to for operating an intake valve or other control as described above.

In yet a third form of the regulating aspect of the invention matters may be so arranged that the engine velocity increases slightly with increase in load. For

this purpose the fuel supply to the engine may be controlled e.g. by an electro-mechanical device as shown in Fig. 4 in response to a voltage which is held substantially constant within a predetermind narrow range, as induced in an auxiliary winding similar to winding 17 of Fig. 1, but in this case the voltage induced therein is according to established laws governing the generation of alternating voltage proportional both to the reciprocation frequency of the magnetic cores 1411-1412 and to the magnetic flux in the magnetic circuit. Thus, when said flux changes simultaneously with a change in the load, the reciprocation frequency is changed inversely so as to maintain the voltage in said auxiliary winding substantially constant.

The approximately constant voltage delivered by the auxiliary Winding can, additionally, be used for such purposes as to charge a storage battery which, incidentally, may serve as the D.-C. source in a system according to the invention, such as source 16 of Fig. 1.

Figs. 3 and 4 schematically illustrate two exemplary embodiments of the electro-mechanical portion of a regulating system according to the last-mentioned form of the invention, i.e. that wherein a substantially constant voltage is put out by an auxiliary winding such as, or equivalent to, the winding 17 in Fig. 1. Referring first to Fig. 3, a throttle valve 21 is shown in a carburetor air intake conduit 22 which forms part of a fuel supply circuit for a floating-piston engine, not shown. Valve 21 is connected by way of pivotal linkage 27-26 with the sliding magnetic core 25 of a solenoid device having a housing 24 and winding supply terminals 23. The core 25 has a flange 29 which is biased into engagement with an abutment member 36 when the valve 21 is in fullyopen position by the action of a spring 28 so calibrated that the core is maintained in its left-hand position of abutment with the member 36 as long as the voltage applied to the solenoid terminals 23 does not exceed a prescribed value. The solenoid terminals 23 are con nected to the output terminals 18a of an electromagnetic system which may be similar to that shown in Fig. 1, in which case the terminals 18a would be identical with the terminals 1% shown in that figure as providing the output from auxiliary winding 17. Should the voltage output from Winding 17 exceed the prescribed value the solenoid core 25 is moved rightward of Fig. 3 thereby partly closing the throttle and reducing the engine speed by such an amount that the voltage across the terminals 18a is restored to the prescribed range.

Referring to Fig. 4, the regulating system is shown as applied to a fuel injector for a floating-piston engine of the direct injection type. The injector assembly is positioned in the wall 1b of the engine cylinder. in jector chamber 31 is maintained filled with fuel under pressure but the fuel is prevented from flowing out of the chamber into the cylinder through an injection orifice 33 by means of a needle valve member 32 normally sealing the inner end of said orifice. The valve member 32 can be lifted off its seat to a variable extent by the action of an electromagnet 34 acting on a magnetic armature secured to the rear end of valve member 32. The winding of electromagnet 34 is energized with volttage pulses delivered from a suitable variable pulse gen erator 35, which maybe of any appropriate electronic type e.g. a conventional monostable or one-shot multivibrator, operated to generate a voltage pulse of predetermined duration upon being triggered by the individual pulses delivered via 18 at each reciprocation of the engine. The input terminals of the variable pulse generator 35 are connected to the terminals 18 which may be the terminals 18 of Fig. l, and the generator is so constructed that when the voltage applied to it from terminals 18 exceeds a prescribed value, the duration of the generated pulses is correspondingly reduced. Such a generator is well-known to those versed in this art and has been described by Jean-Marie Moulon in his book Les 7 systems.

900,016. The periods during which the injection valve 32 is open are reduced accordingly and so is the rate of fuel supply to the engine. The engine operates at a slower rate until the voltage across terminals 18 has been restored to its prescribed range.

It will be understood that in the general showing of Fig. l the block C may indicate any intermediate electromechanical relay device such as the solenoid device of Fig. 3 or that of Fig. 4, which relay device in turn controls the operation of the engine as indicated by the connection D in Fig. 1.

An embodiment of the invention will now be described in its application to the synchronization of a pair of floating pistons. In its preferred form a floating-piston engine comprises one or more cylinders each containing a pair of svmmetrically operating pistons reciprocating in opposition to each other, and which may be termed conjugate pistons. In operation the desired accurate opposition between the reciorocations of the two coniugate pistons tends to be disturbed by various factors which introduce phase displacements between the'respective operating cycles and the correct operation of the engine requires the provision of some synchronizing means for maintaining the desired opposed relationship between the pistons at all times. Conventional synchronization systems for floating-piston engines have generally been mechanical in character, involving the provision of symmetrical linkages connected with the respective pistons and with each other by way of a suitable kinematic transmission. In operation, the linkages are subjected to very high accelerations and consequent stresses, and limit to the operating speeds achievable with engines of this type. Moreover such linkages are generally objectionable in that they destroy the truly free-floating characteristic which constitutes the fundamental advantage of such engines.

Other known types of synchronizing systems for floating-piston engines are pneumatical rather than mechanical and operate by way of the usual air cushions normally present in such engines. Such pneumatic synchronizing systems can be controlled electrically or mechanically.

In the systems of the present invention synchronism is achieved between the operation of coniugate pistons in a floating-piston engine by associating with each piston one or more movable magnetic elements such as 14a and 14b of Figs. 1 and 2, cooperating with a pair of electromagnetic systems each of which may be of the same general character as shown in those figures which systems are so coupled with each other (electrically or magnetically) that, in case of a disturbance in the synchronism (or a phase displacement) between the reciprocations of the two magnetic elements (or sets thereof), electromagnetic forces are set up which act upon said elements to restore them to synchronism.

The electromagnetic systems associated with the two pistons are preferably coupled together electrically to' cause an interchange of electric power between the two systems in the event that the reciprocations of the magnetic elementsthereof tend to fall out of step, so that power is transferred from one to the other of the systerns and applies to one or each magnetic element a force acting to restore it into synchronism with the other element. For this purpose, the circuits of windings such as 15a and 15b in Fig, 1 may be connected in opposition to provide a balanced circuit, 'e.g. by connecting the midpoints of the respective windings, or/and by connecting the ends of both windings in parallel across a further winding provided on the third arms of both electromagnetic Fig. '5 illnstrates'suclran embodiment" of the invention wherein a cylinder 36 has two floating

pistons

37 and 38 reciprocating therein, and normally adapted to be positioned in opposition to each other on either side of the transverse midplane EE' of the cylinder. The cylinder is shown as including a pair of intake ports 39 and a pair of transfer or bypass conduits 40. The exhaust ports lie outside the plane of and hence cannot be seen in Fig. 5. Secured to the

pistons

37 and 38 are rigid transmission rods 41 and .42, respectively, which serve to drive a load mechanism, not shown, such as a compressor or converter of mechanical energy. The load mechanism forms no part of the present invention and is not illustrated but can be assumed to be interposed in the broken sections 41a and 42a shown in each of the

transmission rods

41 and 42.

Each transmission rod further has connected with it an air-cushioning device, of the general type shown as 10, 21 in Fig. 1, and serving to provide for a smooth reversal of movement of the pistons at each outer dead center position. Said air cushioning devices are here shown as comprising pistons 45 and 46, respectively secured on the ends of

rods

41 and 42 and operating in cylinders 42 and 44, respectively.

Each

transmission rod

41, 42 carries intermediate its length a

magnetic section

47, 48, respectively, each cooperating with an electromagnetic assembly of a construction somewhat different from that shown in Fig. 1. The two assemblies being identical only the left hand one of the two shown in Fig. 5 will be described, the components of the other system being designated with the same reference numerals followed by sutfix 11 instead of a.

Said electromagnetic assembly comprises a three-legged magnetic core having the side legs 49a and 51a and a center leg 50a, all enclosed in a casing 61a. The median portions of legs 49a and 59a are formed with cutouts to provide Wide airgaps within which the magnetic element 47 secured to the piston 37 is reciprocable. The leg 51a is not formed with a cutout and it will be noted that in case the said third leg 51a is positioned in the longitudinal center plane of the system as illustrated, the

piston rods

41 and 42 would have to include two pronged sections surrounding said third legs 51a and 51b, respectively, in order to permit unimpeded reciprocation. The side leg 49a carries an energizing winding 53a (which may include one or more separate winding sections), and the leg 50a carries a winding 52a. Windings 52a and windings 53a are connected in series relation and with a D.-C. source 544': by

leads

55a and 56a. While separate D.-

C. sources

54a and 54b are shown, a common source should preferably be used.

The

windings

52a and 53a are wound and connected in such a way that they tend to create magnetic fluxes of reverse sign in the third core leg 51a. In view of the cyclic variations in reluctance produced in legs 49a and 59:: by the reciprocation of the element 47, an alternating magnetic flux is generated in the third, fixed-reluctance leg 51a, since the resultant flux in the latter corresponds to the algebraic sum of thefluxes generated by the two windings.

Furthermore, as a result of'the cyclic variation in reluctance in the legs 49a and 50a electromotive forces are induced in the

windings

52a and 53a. It will be readily understood that if the electromagnetic system associated with the right-hand piston 38 accurately presents characteristics similar to those of the system associated with the left-hand piston, then by providing cross connections between one or more symmetrically disposed points of the two circuits associated with the respective systems there willbe obtained a balanced output circuit in which no current will flow as long as the reciprocations of the movable

magnetic elements

47 and 48 are efiected in. strict phase opposition with one another, but there will be current flow in one or the other sense over said cross connections should a phase displacement occur between the reciprocation of the two elements;

Electrical energy is thus transferred from that system in which the movable element is in leading relationship to the system in which the movable element is lagging, and the electrical energy thus transferred generates a magnetic force which imparts to the lagging

element

47 or 48 the requisite surplus of kinetic energy for bringing it back into synchronous relationship with the other element. The force thus acting to restore synchronism between the two movable elements and hence the pistons respectively connected thereto, increases at a very rapid rate with the degree of phase displacement between the two elements. Thus, the differential voltage appearing across the ends of the synchronizing connection such as 57 in Fig. 5, for a linear phase displacement between elements 47 and .3 as low as A the reciprocation amplitude of each element, can be many times the value of the excitation voltage applied at 54a and 54b. Moreover it will be noted that the large forces thus developed are axial forces applied exclusively to the simple, rugged

magnetic elements

47 and 48 solidly connected and with the pistons, rather than being applied to complex pivotal linkages as in conventional mechanical synchronizing devices.

The cross connection or connections between the two symmetrical circuits can be variously arranged to provide the balanced synchronizing circuit, a simple arrangement being that wherein the synchronizing cross connection 57 connects the midpoints between the pairs of windings 52a-53a and 52b-53b, as shown in Fig. 5 alternatively, a balanced synchronizing circuit may be obtained by providing on each core additional windings such as the windings 58a, 58b shown encircling the third core legs 51a and 5112 respectively, and by connecting such windings in parallel as shown by the

connections

59 and 60. While the resulting circuit might be used for the purpose of synchronization just described, it is here shown as serving to provide an additional output at terminals 18a which may be used for regulating purposes in a manner generally similar to that described in connection with the other embodiments.

It will be seen that the invention provides highly advantageous arrangements for the operation and regulation of engines of the floating-piston type, particularly with respect to the starting, supply-regulation and synchronization of such engines. The regulation provided by the invention is of a very accurate and flexible character, has a low response time, and is especially advantageous in connection with floating-piston type engine since in such engines the reciprocatory operation does not tend to be regularized by associated mechanical couplings such as connecting rods and crankshafts as in conventional reciprocating engines. The synchronizing function provided by the invention also is more advantageous than the means heretofore provided for a similar purpose. A further advantage of the invention is the facility with which the various arrangements thereof can be combined with one another, as mentioned at various points throughout the specification, and also combined with the applicants prior electromagnetic systems such as the variabledrive movements-conversion systems for floating-piston engines described in applicants US. Patent No. 2,829,276 already referred to.

As mentioned hereinabove the illustrated embodiment should not be construed as restricting the invention since various modifications may be made in the constructions illustrated and also in the applications ex plicitly mentioned, without departing from the scope of the invention. Thus, among the many possible structural modifications, it should especially be noted that the magnetic circuit means may assume a variety of forms other than that of a three-legged (or El-type) core. Multilegged cores are well known in the art, e.g. in magnetic transformers, and are known to admit of a very wide range of variations in shape and in the disposition and connection of windings thereon, and similar variations 10 will be readily conceivable regarding the magnetic systems utilized in the invention. the airgaps in the core in which the movable magnetic element or elements is or are slidable can also be varied. For example, the solid core legs 51a and 51b in the embodiment of Fig. 5 may be arranged outside the plane of the other legs of the core (i.e. outside the plane of Fig. 5) thereby reducing the length of the magnetic systems in directions parallel with the directions in which the pistons reciprocate.

What we claim is:

1. In combination with a floating-piston engine having a cylinder and a piston therein, means defining a magnetic circuit, a magnetic element secured to said piston and cooperating with said magnetic circuit for cyclically varying the reluctance thereof on reciproation of the piston, winding means inductively associated with said magnetic circuit, an electric output circuit connected to said winding means for providing a variable output in response to variations in the reciprocation of said piston, and means for feeding back said variable output to said engine for regulating the operation thereof.

2. In combination with a floating-piston engine having a cylinder and a piston therein, means defining a magnetic circuit, a magnetic element secured to said piston and cooperating with said magnetic circuit for cyclically varying the reluctance thereof on reciprocation of the piston, winding means inductively associated with said magnetic circuit, an electric output circuit connected to the Winding means for providing a variable output in response to variations in the reciprocation rate of said piston, an adjustable feed regulating member for said engine, and means connected with said output circuit and said regulating member and responsive to said variations in output for adjusting said member.

3. The combination claimed in claim 2, wherein said regulating member comprises a settable valve, and said output responsive means comprise electromagnetic winding means connected to said output circuit and a spring biased armature positionable by said electromagnetic winding means in response to said output variations and mechanically connected to said valve.

4. The combination claimed in claim 2, wherein said regulating member comprises an intermittently operable injector valve member, electromagnet means associated with said member and energizable with voltage pulses for intermittently operating said member, a variable pulse generator connected for energizing said electromagnet means, and means connecting said pulse generator to said output circuit for varying the duration and timing of said pulses.

5. The combination claimed in claim 2, wherein said responsive means is responsive to the frequency of said output, and including means for converting variations in said frequency into regulating displacements of said member.

6. In combination with a floating-piston engine having a cylinder and a pair of opposed conjugate pistons IEClPI'O cable therein, means defining similar magnetic circuits associated with the respective pistons, magnetic elements secured to the respective pistons and cooperating with the respective magnetic circuits for cyclically varying the reluctance thereof, energizing winding means inductively associated with said respective magnetic circuits, and means connecting the respective windings in a balanced electric circuit, whereby a lack of synchronism in the reciprocation of both conjugate pistons will result in a flow of current over said balanced circuit and a consequent transfer of energy from one magnetic element to the other effective to restore said synchronism.

7. In combination with an engine of the type described having a cylinder and a piston reciprocable therein, a multi-legged magnetic core having spaced legs each formed with a gap therein, magnetic elements secured to the piston for reciprocation therewith and adapted to The arrangement of st bstantially fill respective ones of said gaps in respective. a d pq ion of the p ston, windings sp i y ssociated with said legs adapted when energized to generate magnetic forces tending to displace said elements into and u of sa d at d gap nd l ctr c ean or en: ergizing said windings in timed relationship to cause a. reciprocation of said elements and piston for starting the in said. lect i mea inclu g mea s or app y voltage pulses to said windings in a timed sequence, and means for controlling the timing of said applied pulses to provide an increasingly rapid reciprocation of said e emen s. duri an ng -sta in operation- References Cited in the, tile of this patent UNITED STATES PATENTS Noacket a1. Dec. 16,

Norton fl v n Nov. 16,

Turner Aug. 11,

, Colgate Sept. 15,

FOREIGN PATENTS France June 9,

France Sept. 29,