US2305290A

US2305290A - Fuel injection apparatus for internal combustion engines

Info

Publication number: US2305290A
Application number: US330125A
Authority: US
Inventors: Fuscaldo Ottavio
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-04-14
Filing date: 1940-04-17
Publication date: 1942-12-15
Anticipated expiration: 1959-12-15

Description

Dc. 15, y1942. o. FUscALDo 2,305,290

FULL INJECTION APPARATUS FOR INTERNAL COMBUSTION ENGINESq Original Filed April 14, 1937 lili INVENTOR Orr/Iwo Fuse/44 0o,

ATTORNEY S.

Patented Bec. l5, i942 essere llflUElL 'ENECTEON APPAR'US FR. ENTER/NAL @GMUS'IFHN ENGENES Uttar/io Fnscaldo, Milan, italy; vested in the AMien Property Custodian Original application April ld, i937, Serial No. 136,733. Divided and this application april i?,

will, Serial No. 33i),25.

5 Claims.

This invention relates to fuel injection appa-- ratus :for internal combustion engines, and more particularly to apparatus wherein fuel is injectn iuel under pressure is supplied to a fuel chamber delivering into the combustion chamber of each engine cylinder through an orifice normally maintained closed by a movable valve having its stem located in the fuel chamber. A part of the valve stem composed of iron has play within a solenoid, forming an armature therefor, the arrangement heing such that, when the solenoid is energized, the valve stem is moved. to open the orifice, thus permitting the fuel which, as previously stated, is under pressure, to be injected into the cylinder, whereas, when the solenoid is deenergizecl, the valve stem under the action of a spring is moved to close the orioe and cut off the fuel supply. There is at least one electromagnetically controlled valve for each engine cylthe duration or period of each fuel injection.

lfliccording to the invention, the control :means includes a series of pairs of contacts, one pair ior each Vengine cylinder and each pair being adapted, when and while the contacts thereof are in engagement to complete an electric circuit that energizes the solenoid of the injection valve associated with that cylinder, thereby opening the valve and admitting fuel into the cylinder. When said contacts are disengaged or separated, the circuit is broken and the solenoid deenergized, whereupon the injection valve is closed. Each pair of contacts includes a non-movable contact which is relatively xed with respect to a ring that surrounds and is concentrically located with re spect to the axis of a rotating cam, and an oppo" siteor movable contact arranged. on a lever or rocker arm having a xed pivot and which has an extension portion or follower adapted to en gage said cam. A spring urges the rocker arm in a direction to hold the follower on the cam and close the contactsbut, because of the cam conm figuration, the closing is permitted only during a' Ybrief portion of the cams rotation, the rocker arm being normally held against the thrust of the lin italy torti itl,

(lll. Zilli-3u) rotation, and in a position wherein the contacts are separated.

Considering that the rocker arm moves from its normal position wherein the contacts are sep arated and open into its position in which the contacts are closed and then baclr again to nor mal position, all in a given angular movement of the cam, it will be apparent that the angular movement can be divided into three stages, nainely, (l) that wherein the rocker arm moves from its normal position to the position in which the contacts are closed, (2) that during which the contacts remain closed, and (3l that wherein the rocker ann moves back to its normal position. Such being the case, it can be seen that by vary= ing the rst and last stages, the intermediate stage will vary inversely; in other words, if the first and last stages are lengthened, the intena mediate stage will he correspondingly shortened;

whereas, if the iirst and last stage are shortened,

the intermediate stage will be correspondingly lengthened. in this way is afforded an effective regulation of the time that the solenoid remains energized and, consequently, the period ci fuel injection.,

in accordance with the present improvements, the regulation referred to is effected by varying the initial or normal distance between the conf tacts of each pair, or the width or their gap when full open, so that, for any given speed of cam rotation, the period of valve opening and iniec=l tion is made relatively longer when said distance is decreased and relatively shorter when the disu tance is increased.v This ei'iect is accomplished by turning adjustably the ring or carrier upon which the relatively hired contacts are mounted, through a limited distance in one direction or the other, depending upon whether the gap between. the contacts is to he increased or decreased to shorten or lengthen the l'injection period. The rotary adjustment of the ring may he accorn= plished either manually or automatically under control of the engine itself.

These and other specific characteristics of the invention will now be explained with special reference to the drawings which are given merely indicatively as examples, but not limitative as to the scope of the invention.

Fig. l is a schematic View of a device embody? ing the invention, which is suitable for engines operating at relatively low pressures.,

Fig. 2 is a schematic view showing the regu1at= ing switch hereof in association with an electro:- magnetically operated valve suitable for two= strokev cycle engines operating atrelatively high pressures, like Fig. 3 of the parent application; the switch being shown in elevation and the valve in vertical section.

Fig. 3 is a sectional view through the switch shown in Fig. 2 taken on the crooked line 3-3 of Fig. 2.

As is shown generally in Fig. 1, the apparatus comprises an electromagnetically governed injector of which there is one for`each engine cylinder 2; a current distributor 4 for governing the supply of current from source 3 to the several injectors on the motor, and which varies in its details according to the number of injectors it has to serve; and the fuel feeding supply 5 and Apipe I0 delivering under pressure to the several injectors. This apparatus varies according as the injection is to be at low pressure into the air feeding conduits of the motor (motors with separate ignition), or at high pressure into the compression chamber of the motor (motors with spontaneous ignition by compression). Since the invention forming the subject matter of this divisional application is concerned chiefly with the switch controlling the operation of the electromagnetically operated valve, the fuel injection valve selected for illustration is one suitable for use with engines operating at high pressures, al-

though it is to be understood the invention is equally applicable to injection valves for use with engines operating at relatively low pressures as previously stated.

The electromagnetically operated valve il1ustrated will rst be described in detail. Within the valve casing 6 is a cylindrical fuel chamber I6, filled at all times with fuel and which during non-injection periods is maintained closed to the combustion chamber 34, by a valve assembly 1 which slides freely in the casing 6, said assembly 1 comprising a valve stem 1b of substantially reduced diameter and formed at its left end with a conical valve portion 1l arranged to engage a valve seat 8 beyond which is the injection ori fice 9.

The valve stem 1b is arranged for limited longitudinal movement in the fuel chamber to effect the opening and closing of the valve, and for this purpose is centrally located and is guided by an enlarged portion 1c formed in the stem near the left or combustion chamber end thereof, and which portion slides on the inner surface of said cylindrical fuel chamber. The enlarged guiding portion 1c of the valve stem is formed with a series of longitudinal grooves or liquid displace` ment passages I8 extending its full length so as,

on the one hand to enable the fuel to flow freely past said portion, and, on the other hand, to enable the valve stem to move freely without hindrance by the fuel.

At its opposite or right end, the valve stem is provided with another enlarged portion or head 1e1 of magnetic material, as for instance iron, this head having a sliding fit with the valve solenoid I3 and constituting an armature therefor. When the valve is closed, the rightmost end of the enlarged portion 1d is located in slightly spaced relation, as shown, with a fixed core portion I0 of the solenoid, which core projects inwardly, through part of the length of the solenoid from a casing, or shroud which houses the solenoid and is mounted upon the valve casing 3. The portion of the armature or movable core which is carried by the valve stem .,1b isiprovided with a cylindrical recess 1, open at the rightend, and in which there is accommodated' a restoring spring I2 reacting between the head dand the fixed core portion I0, the spring constantly urg ing the valve to its closed position.

Since the solenoid shroud II is of magnetic material, there wil be a substantially complete path of magnetic material for the flux of the solenoid, broken only by the normal slight gap between the fixed core portion carried by the casing and the movable core or armature carried by the valve stem.. Liquid displacement passages |5 at the base of the recess in the armature portion 1d permit the free fiow of fuel between the main valve chamber and the recess 1. n

According to the arrangement just described, when the solenoid I3 is energized, the armature ld carried by the valve stem will be moved instantaneously, against the resistance of the spring |2, in a direction to close the magnetic gap, and this movement will effect an instantaneous and complete opening of the valve so as to allow the discharge of fuel for injection toward or into the combustion chamber 34. Later, when the solenoid is deenergized, the spring I2 will act instantaneously to move the valve to its closed position, thus cutting off quickly the flow of fuel and injection. Because of the liquid displacement passages I5 in the armature and the grooves or liquid displacement passages |8 in the enlarged portion Ic near the left end of the valve stem, it will be apparent that the valve assembly is in effectfloating and freely movable in the liquid fuel, and that there is no pumping action which, on the one hand, wouldretard the movements of the valve to its opened or closed positions, or, on the other hand interfere with the flow of fuel to the combustion chamber 34 when the valve is opened. The quick closing is enhanced by the fuel outflow in the same direction.

Corning now to the distributor switch 4, the details of which are shown in Figs. 2 and 3, this consists of a series of pairs of contacts, one for each cylinder, each pair comprising contacts |25 and |28 and the several pairs, t'wo being shown, being arranged equidistantlyfrom each other in a series arranged around a cam |22 which is mounted upon a cam shaft |22a journalled in a support |30 attached to a fixed shell or casing I21. There being one pair of contacts for each cylinder of the engine, the cam |22, depending upon whether the engine operates on the fourcycle or two-cycle principle, rotates at half the speed or at the same speed as the main shaft of the engine. Each pair of contacts includes a relatively fixed contact |28 mounted upon a carrier or annular ring |29 which is seated movably in a groove formed for the purpose in the support |30. Each of the other contacts |25 is mounted at the outer end of a pivoted lever or rocker arm |2|, these lever arms being pivoted each upon a pin |23 fixed in the support |30. The relation between each pair of vcontacts may be initially set by a threaded and nutted mounting |28 of each non-moving contact |28.

The rocker arm |2| may be of non-conducting y material,k or the contact |24 may be insulated thereon, whereas the ring |29 may be an electriaaoaaao cal conductor as also the spring |24. Electrically connected to the spring |24 is a' binding post |26 from which a conductor extends to the solenoid I3, another lead extending from the solenoid to a source of electrical energy, as, for instance, a batquickly opening the injection valve for a. predetermined duration so as to permit the fuel to be injected into the cylinder for this period as previously described; and when the contacts |25 and |28 become separated, the electrical circuit is broken, thereby deenergizing the solenoid, causing the valve to be closed by the action of the spring I2, and terminating the injection.

The timed opening and closing of the contacts |25 and |28 is controlled from the cam |22. This cam has a general contour portion which may be concentric and will be called the high portion z, also a low portion z, and the two inclines y, y between :r and z. When the rocker arm |2| is opposite the high portion x of the cam, the contacts are disengaged, as seen at the right of Fig. 2, whereas when the rocker arm is opposite a low portion z or part of y of the cam, engagement of the contacts is effected by the action of the spring |24 asl seen at the left.

the period in which the contacts .remain in engagement. And conversely, when the contact |28 is shifted in a direction to shorten the gap between the contacts, the time-required for the rocker arm to move between its extreme positions will be shortened, and the time of contact engagement will. be correspondingly lengthened.

' In this way, the periodof energization of the The drop y of the cam from its highest portion a: to its lowest portion z-is gradual as is also the corresponding rise y of the cam. As the cam rotates, it will be apparent that as the rocker larm 2| rides down along the drop y', it will swing under the action of the spring |24 until it is arrested by the engagement `of the contacts which then remain closed until the rocker arm is picked up again by the other slant or rise, whereupon the contacts become separated. Thus, the rotation or angular movement of the cam from the time the rocker arm leaves the high portion thereof until the time it is again engaged by the high portion of the cam can be divided into three stages, as previously explained, the intermediate' stage (2) being that during which the contacts remain in engagement, a ilrst stage (I) during which the rocker arm moves from its normal position to its contact engaging position and a last stage (3) during which the rocker arm moves from its contact engaging position back to normal position. Consequently if the first and last stages are adjustably varied the intermediate v Astagewill be varied in an inverse manner. That is, assuming a given speed of rotation of the cam,

it will require a fixed period or time, or of angular rotation, for the cam to rotate from the position wherein the rocker arm leaves the high portion thereof to the position wherein it again attains the high portion of the cam. IIt follows from this that the period during which the contacts |25 and |28 remain in engagement will depend upon the time itl takes the rocker arm to move at constant speed between its two limits of f motion (provided by the cam portion :r and the solenoid I3, and consequently the period of fuel injection, is regulated.

The adjustment of all of the contacts |28 for such regulation is simply and readily effected by adjusting the ring |29 on which the contacts |28 'are xedly mounted. A very slight rotary adjustment of the ring changes substantially the of ring |29 is brought aboutby the following illustrative means. A rockshaft 3| joumalled in the 'casing |21 near the bottom thereof, carries at its inner end an offset or eccentric portion or stud |3|a which enters a slot |29l formed in the ring |29. An operating handle or arm |32 pinned to the shaft .|3I at the outer end thereof forms a convenient device for the rotary adjustment of the shaft |3I to effect the adjustment of the ring. This arm 132 may be either manually controlled or automatically controlled from anv engine governor, or by connecting the arm with manometric capsule or other pressure responsiveinstrument operated for example from the engine intake pressure. Since there is a contact |28 mounted on the ring |29 for each engine cylinder, the period of fuel injection in all -of the cylinders will be the same, since all the contacts will partake of thesame degree of adjustment, when the shift of handle |32 adjusts the ring.

Whilegin the embodiment disclosed the contacts |28 are those through which regulation is effected, through the ring |29, it will be apparent that the adjustment could be reversely effected equally as well by maintaining the ring |29 xed and providing instead for the rotary adjustmentof the circular member |30.

In the accompanying drawing the invention has been shown merely by way of example and in preferred form, but obviously many Yvariations and modifications may be made therein which will still be comprised within its spirit. 'It is to be understood therefore that the-invention is not limited to any specific form or embodiment, except in so far as such limitations are specified in the appended claims.

What is claimed is.:

l. A circuit controller or distributor for a. series of electromagnetic actuators adapted to effect the timed closing and interrupting of the circuits of the respective actuators thereby to de.- termine the duration of each energization thereof said controller comprising for each circuit a pair of contacts having separate supports and normally spaced apart on their supports with a predetermined open gap, an operating member or rotary cam for regularly causing the to-and-fro movement of the rst contact on its support Y across the spacing gap ,thereby to close and incontact |28) since the speed -of rocker arm swinging movement does not vary. assuming as previously stated that the cam is rotating at a given speed. Consequently an adjustment of the contact |28 in a direction to widen the normal gap between the contacts will lengthen the time necessary for the rocker arm to move between its extreme positions and consequently will decrease terrupt the circuit with a predeterminedperiod of closure, and means tc adjust one of said supports relatively to the other to vary the normal width of open gap between the two contacts thereby to regulate the period of each closure of circuit and the duration of each energization of actuator. Y

2. A controller as in claim 1 and wherein the operating member is an open cam with spring- 44 pressed follower thrust by the cam to retract themovable contact.

3. A'controller as in` claim 1 and wherein the `adjusting means, lever or handleis connected to adjust finely the position of the support of the non-moving contact.

4. A controller as in claim 1 and wherein the tion thereof; said controller comprising for each circuit an active and a passive contact-mounted I on separate supports. and normally spiced apart operating member is an open cam with sprinz-` f on their supports with a predetermined open gap, the support of the several passive contacts being shiftable annularly, a central rotary cam for regularly causing the toandfro movement of the active contact on its support across the spacing gap thereby to close and interrupt in sequence the several circuits with a predetermined 'angular period vof closure. and means to adjust annularly said rotarlly shiftable support relatively to the other support to vary finely the normal width of open gap between each pair of contacts thereby to regulate the angular duration of each closure of circuit and each enersization of actuato v OfI'rAVIO FUBCALDO.