US1463855A - Ignition device for internal-combustion engines - Google Patents

Description

Aug, 27, E923,

Filed July 14, 1921 S Sheets-Sheet l IIgI /7/s/7Trof? NSY Aug., 7, H923, v MB E. H. TARTRAIIS.

IGNITION DEVICE FOR INTERNAL-COMBUSTION ENGINES Fig@ ug. 7, E923.

3,463,855 E. H. TAM-mus IGNITION DEVICE FOR INTERNAL COMBUSTION ENGINES' Filed July 14, 1921 3 Sheets-Sheet 5 @y m/C/ Patented Ang.. 7, 11923..

EUGNE HENRI TARTRAIS, 0F MAISONS-LAFFITTE, FRANCE.

IGNITION DEVICE FOR INTERNAL-COMBUSTION ENGINES.I

Application filed July 14, 1921. Serial No. 484,805.

T o all whom t may concer/n.1

Be it known that I, EUGNE HENRI 'IAR- TRAIs, citizen of the French Republic, residing at. Maisons-Laffitte, Seine-et-Oise, in the Republic of France, have invented new and useful Improvements in Ignition Devices for Internal-Combustion Engines, of which the following is a specification.

My invention relates to a device for effecting the initial ignition of the charge in internal combustion engines wherein lliquid fuel is injected into the working cylinder, said liquid fuel being chiey heavy oils. In such engines, the ignition is auton'iatically carried out when in normal running, but upon starting and when the engine is cold, the ignition requiring the use of an igniter I have ascertained that an ignition device of this kind should comply with the following conditions. Upon starting inasmuch as the Carburation is very imperfect, the fuel should be enabled to reach the igniter, and after the first ignitions have been effected, the gases which are in a state of whirling motion, this condition increasing with the speed of the engine, should be prevented from directly reaching the igniter, as they wouldcool the latter to an undue extent and the ignition would cease beforethe normal operating conditions has been attained. When the normal Conditions of working have been established, it is likewise necessary to break the elec-tric current which supplied the said igniter during the starting in order to prevent the melting of the filament.

Furthermore, @en the engine is operating at regular speed, the gases in whirling motion now become highly heated, and all parts of the igniter` must withstand the very high temperature which will prevail.

The device tobe described hereunder is intended to provide for these various conditions.

The accompanying drawings show by way of example various embodiments of my invention.

Fig. l is a longitudinal section of the igniter proper..

Fig. 2 shows a detailof-the filament and the coupling plugs thereof.

Fig. 3 is a section of the upper part of the engine showing the ignition plug in position and the relief cock, this representing a two-cycle engine; the oriices for the fluid disposed at the lower end of the'cylinder are not shown.

Fig. 4 shows in the case of two cylinders the relief cocks with their control device combined with the control device for the -igmtion current, in the closed position of the cocks.

Fig. 5 shows a modiied form of the outer terminal of the ignition plug.

1 indicates a. working cylinder of the engine having moving therein the piston 2 provided with a cylindrical extension 3, which latter is adapted at the end of the compression stroke, as herein shown, to engage an annular member 4 screwed into the combustion chamber 6. An annular space 5 is left between the extension 3 and the bore of the member 4. 7 indicates the cover of the combustion chamber and 8 the atomizing device for admission of liquid fuel. A water circulation 9, 9a, is provided around the cylinder and the atomizer; the water inlet and outlet orifices are not shown.

The ignition device used for the initial ignition comprises a. main body 10 screwing into the chamber 6 and a metal filament 11 of platinum-iridium or like alloy which is mounted upon the plugs 12. A central conductor 13 is provided at the end thereof with a head 37 resting upon an insulating bushing 14 of quartz, steatite, or the like, the said conductor being surrounded by an insulating sleeve of plastic material 15 such as asbestos, and by a like sleeve 15a which is held by a pressing member or follower 16. The insulating washer 17 o-f asbestos, mica or the like is used to insulate the member 16 from the main body 10 of the igniter. A spring 18 bears upon the said pressing member and maintains the conductor 13 in position, the said spring pressing against a washer 19 which forms at the same time a spring terminal for holding a wire connector.

In the wall of the cylinder is disposed a relief cock 20 for connecting the interior of the cylinder with the exhaust chamber 23 through the passages 21, 22. The passage 21 is closed by the piston in the position here represented. The distance .fr correspends to about 1l the stroke. The relief cock 20 of each cylinder is provided with the control lever 24. In the example here represented wherein the engine has two cylinders, the levers 24 of the two cocks are connected together by a rod 25 (Fig.v4). The cable 26 provided with the ring 26 are used to draw upon the said rod in order to open the said cocks, the latter being returned to their closed position by the spring 27. The rod 25 actuates a switch lever 29 carrying a carbon brush 30 which may contact with an.insulated Contact piece 31 which is connected for instance with the negative pole of a battery.

Before explaining the operation of the device, it is preferable to set forth the working of the engine under the normal running conditions. The engine of the two-cycle or four cycle type takes in air exclusively into the cylinder in the first place, this air being then strongly compressed in the cylinder on the return stroke of the piston. When the piston has made about 0.93 of its stroke, or in other words when the crank is situated at about 25, before the inner dead point, the edges 32 and 33 will reach the same level as shown in the broken lines Fig. 3 and the air contained in the chamber 34 thus temporarily formed between the piston and the end of the cylinder will be violently impelled into the combustion chamber through the annular space 5 vand will assume whirling motion according to the arrows 35. During this transfer, the atomizer 8 projects a spray of liquid fuel according to the arrows 36 in an equal distribution about the axis thereof. This fuel, which is admitted without air, on the solid injection principle, is taken up by the annular air stream 5 and drawn into the portion in whirling movement 35. The more volatile portions are at once vaporized and mixed with the air. The portions still in the liquid state are projected by centrifugal force against the walls of the chamber which are in a highly heated state in the absence of any water circulation; the said portions are thereby vaporized in turn and the gases thus formed becomes included in the moving current 35. At this time, under the combined action of the heat of compression and that of the walls, the ignition takes place, giving rise to a substantially isopleric combustion. The cycle is then 'completed in the known manner.

It will be observed that these conditions of operating are very unfavorable for the starting of the engine. The latter being cold at this moment, a small part of the fuel is vaporized instantly'while the remainder is projected against the cold wall and is thus lost. These drawbacks have been obviated by the following dispositions where` within a recess 42 and thus removed from the whirling air, and as soon as the fuel reaches this small chamber it becomes vaporized and is ignited. 'A small explosion takes place in this side recess, and a flame is thereby projected into the main chamber which will be enabled to ignite the fuel conta-ined therein in the liquid state but in a state of sufficiently fine division. rlhe imperfect combustion which ensues will however be sufficientto enable the engine to rotate without load, and at each succeeding instant the combustion effects will become better by reason of the very rapid heating of the walls of the combustion chamber which are purposely made thin.

The first ignition effects are obtained in this manner but as the speed increases, it becomes necessary, as stated in the introduction, that the whirling air shall not be directed upon the igniter to such an extent as to extinguish the same,'but nevertheless the fuel mixture should flow at least slightly over it in order to renew the surrounding air. This result is still obtained by reason of the location of the ignition plug. The gas stream 35 flows in fact parallel to the entrance of the recess 42, and the gases around the filament 11 are renewed simply by the slight movement or eddies in the fluid which takes place at the entrance. Experiments will readily show the most favorable distance which the filament should be inserted into the said recess.

When the temperature rises in the combustion chamber, .it becomes necessary to break the electric current passing in the filament, inasmuch as the latter would be heated by two different sources and would soon become melted irrespectively of the alloy which was used. To prevent any neglect in breaking the current, the control of the relief cock is combined with the control of the ignition switch, as shown in Fig. 4. In this manner the ignition current is necessarily broken upon closing the said cock. It will be observed that it is hardly possible that the operator would forget to close the cock, inasmuch as the engine could not be used under these conditions, and moreover, as in the example herein represented, the cock may be provided with a spring-controlled closing ydevice and opened for instance by means of a cable provided witha ring for hand control. Even in case the operator should see fit to draw upon the ring for an indefinite length of time or to attach the same, this would have no effect upon the ignition device, for the heat supplied to the filament under these conditions is not sufficient to melt the same.

On the other hand, the ignition device itself is constructed in a special manner whereby it is enabled to withstand very high temperatures. When the combustion Lacasse chamber is raised to a red heat, the ignition device thus exposed will be likewise heated to redness. Although no exact measurements of temperature have been made, it appears probable that the forwardly situated portions reach or exceed 1000 degrees C. as observed by the color of the visible parts. Under these conditions it is evident that special precautions will be necessary in order that the device shall have a sufficient mechanical strength and shall not be subject to oxidation, and that it shall be Huidtight and electrically insulated.

The insulation is herein facilitated in a satisfactory manner by reason of the very be observed in F ig. l that the insulating ring 14 which is produced by machine and ground as in the case of a mechanical piece 1s disposed and adjusted in a recess formed in the end of the main body 10. The central conductor, which is made of a special alloy as for the main body, is itself fitted in the ring 14 with only the necessary play, not shown, to provide for the expansion thereof. The head 37 thereof which is fitted closely upon the end of said ring is caused to enter to a fairlv considerable extent into the said recess in order to provide between the two metal pieces, the main body and the insulated central conductor, a certain play 38 which is made as small as possi-ble. The effect of this arrangement upon the electrical insulation will be set forth hereunder.

`From a mechanical standpoint, the advantages are at once apparent. Should the ring 14 be brokemthe pieces which might fall into the engine will necessarily be very small whereby they will occasion practically no damage, but this circumstance will not occur as a matter of fact. While it is true that the said ring is subject to occasional breakage when it is made of certain substances such as steatite, this breakage is in fact of rare occurrence, and in any case will give rise to large-sized pieces all of which may be found upon dismounting the device. Under these conditions the ignition device is or appears to be of a good use, by reason of the low voltage employed. This same circumstance enables the use of the very small amount of play 38. ln fact, the operation of this engine is such as to obviate any deposit of carbon when working under the normal running conditions,

by reason of the high temperature ein ployed.. At starting, and'when the engine is cold, a deposit of carbon is certainly produced in such manner as to temporarily obstruct the space 38, but this is automatically cleared away by reason of the high temperature. During the time when the said deposit remains, this carbon which is only recently formed appears to lack the necessary cohesion to cause it to constitute a body having sufficient conductivity to afford any considerable shunting of the current, and the operation will therefore not be subjected to any inconvenience for this reason.

The joint as well as the insulation of the central conductor are provided for in a special manner. `When the ignition plug is subjected to the action of the fiame, the entire length of the central conductor is at a substantially higher temperature than the main body 10 which is cooled by the outei air throughout the whole of the exterior portion thereof, this having a small diameter as shown in F ig. 3. This will render it impossible to use either a cement or a joint in which end pressure is exerted by means of a simple screwthread. According to the construction herein employed, the conductor passes through the main body with the inter-position of the plastic insulating sleeve (of asbestos) 15 which is only slightly pressed in order to provide for the loose sliding of the conductor. The spring 18 is caused to bear through the intermediary of the pressure member 16 upon the main body 10 in such manner as to constantly maintain the ring 14 well pressed between the body and the head of the conductor. lf the said ring were free to move, it would soon become reduced to powder. rlhe sleeve 15 which is only slightly pressed is not sufficient to provide for a tight joint, but this 'latter is obtained by the washer 17 which at i the same time constitutes an electric insulator and by the pressure member 16. The bottoni surface of the member 16 is so designed that the total pressurev which. may be exerted upon the said'base by reason of Ithe inner pressure of the engine, and consequently the force of the spring 18 counterbalancing this latter, shall correspond to a I tractive stress affording all desired safety in the portion 13a 0f the central conductor" this portion being subjected to the greatest strain by reason of the temperature-and to a compression stress likewise affording all desired safety for the ring 14. The spring 18 is sufficiently removed from the source of heat by reason of the long and narrow form of the ignition plug, and is sufficiently cooled by the air not to lose its temper. The current conducting terminal has preferably the form of a slotted end 19 rat-her than a screwthreaded end, for in case the conductor 13 should be rotated unawares by a nut engaging said screwthread, the filament might be damaged thereby,

The filament is secured at one end thereof to the main body and at the other end to the conductor by means of connecting plugs 12 made of an alloy of a refractory nature which are sufliciently free from oxidation and preserve a sui'licient mechanical strength when heated, and having substantially the same coefficient of expansion as the members (the main body and the said central conductor) wherein they are secured by means' of conical ends inserted after the manner of pins. The heads of the said plugs have small apertures formed through the same wherein are inserted the ends of the filament, these latter being then seated by means of a small press. A more suitable electric contact may be obtained by a small soldered joint. at 40, ybut not at 41, inasmuch as in this case owing to the danger of melting the lament, a more readily fusible soldering substance would be required.

Fig. 5 shows a modified form of construction of the terminal portion of the ignition plug. The central conductor 13 is provided with a slot 48 at the end thereof for making suitable contact with the bell-shaped member 42 having formed therein the apertures y43 for cooling the spring 18 and secured firmly to the main body 10 by the screwthreaded ring 44. The said bell-shaped member is insulated by the washers 17 and 45. The device is completed by the nut 46 whereby the wire 47 may be clamped without any risk of turning the central conductor 13, the free expansion and the tight fitting of the latter being secured by the same members as above mentioned.

It is obvious'that this vinvention is not limited to the details of construction hereinbefore set forth. f

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. An ignition device for effecting initial ignition in internal combustion engines, comprising a combustion chamber having the shape of a torus, a valve fuel atomizer extending into said combustion chamber and adapted to inject the fuel under the forin of a thin sheet at right angle to the axis of the combustion chamber, a recess formed in the wall of said combustion chamber on a level with the valve of the atomizer, and an electric igniter with an incandescent filament mounted on said combustion chamber in such position that the incandescent filament is located in the said recess, and may be reached by the atomized fuel discharged by the atomizer.

2, An ignition device for internal combustion engines comprising a combustion chamber having the shape of a torus, a valve fuel atomizer extending into said combustion chamber, a recess formed in the wall of said combustion chamber on a level with the valve of the atomizer, and an electric igniter,

the incandescent filament of which is located recess in the body and is separated by a small gap from the inner lateral wall of said recess, an insulating layer surrounding the central rod, a ring made of an insulating material, between the head of the rod and the bottom of the recess in the body, yielding means for pressing the head upon the ring and a filament extending from the body to the head of the rod.

3. An ignition device for internal combustion engines comprising a combustion chamber having the shape of a torus, a valve fuel atomizer extending into said combustion chamber, a recess formed in the wall of said combustion chamber on a level with the valve of the atomizer, and an electric igniter, the incandescent filament of which is located within the said recess, said igniter comprising an igniter body having a recess in its inner end, a central conducting rod extending through said body and having'a head which extends by a short distance into said recess in the body and is `separated by a small gap from the inner lateral wall of said recess, an insulating layer surrounding the central rod, a ring made of an insulating material, between the head of the rod and the bottom of the recess in the body, packing pressing members surrounding the rod, an insulating washer between said packing pressing members and the igniter body, a nut screwed on the rod, a spring between the nut and the packing pressing members and a filament removably secured at its ends to the igniter body and the head of the rod, respectively.

4. An ignition device for effecting initial ignition in internal combustion engines comprising in combination: a working cylinder, a combustion chamber in communication with said cylinder, an igniter on said combustion chamber, means for supplying said igniter withA electric current, current controlling means for interrupting said current, a relief cock on said working cylinder, means for operating said relief cock `and means for operatively connecting said current controlling means and said means for operating the relief cock whereby the current is broken when the relief cock is closed.

In testimony whereof I have signed my name to this specification.

EUGNE HENRI TARTRAIS.

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