US1424185A - Device for simultaneously starting a plurality of internal-combustion engines - Google Patents

Description

M. SCHAFER.

DEVICE FOR SIMULTANEOUSLY STARTING A PLURALITY OF INTERNAL COMBUSTION ENGINES.

APPLICATION FILED 0c.12.1919.

11 AQNJ 85 Patented Aug. 1, 1922.

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Application filed December To all whom it may concern:

Be it knownthat 1, Max SCH'AFER, a citizen of Germany, residing at Stuttgart, Germany, have invented certain new and useful Improvements in Devices for" Simultaneously Starting a Plurality of Internal-Combustion, Engines, (for which I have filed an application, in Germany September 2, 1918, No. 319,065), of which the following is a specification:

Many internal combustion engines for aeroplanes and 'airshi s are now made with a verylarge number 0 cylinders. The usual numbers of cylinders in earlier practice were six and eight, but now-a-days twelve cylinders are frequently met with. If the speed of engines having a hi h number of c lin-' ders, say twelve, excee s a certainlimit, it is not impossible that the magneto ignition apparatus arranged for the ignition of all of the twelve cylinders will fail, because the interruptions of the primary circuit occur in a too rapid succession. High speed twelve I cylinder engines of this kind are therefore frequentl ignited in two. groups with two six-cylin er ignition ap aratus in such a about by one apparatus to-be followed when the engine crank has turned through an angle of by an ignition due to the other apparatus. In the same measure as the described substitution of a twelve-cylinder ignition apparatus by. two six-cylinder ignltion apparatus is suitable for causing ignitions during the regular wolrking of the engine, it is unsuitable for this purpose in the case of starting ignition devices having starting magnetos with crank handles. For" if the starting magneto? were to be connected to only one of the two six-cylinder apparatus,

only one group of six cylinders of the twelvecyhnder engine won (1 be supplied with ignition currents; The starting ignitions of two consecutive cylinders would then occur at intervals corresponding to crank turns of 120, instead of 60 as required. But intervals ofl20 are too large because with such intervals a single starting ignition would have to overcome the resistance of com ression of several cylinders.

I recourse were had to another expedient, which consists in dividing the current lead from the one starting magneto used into two ignition brought Specification of Letters Patent. P m mm 19 1922,

12, 1919. Serial No. 344,477;

branches, and in connecting each branch to one of theosix-(iylinder apparatus equipped with a starting evice, there would be a poss blllty that, when the rotating distributing member is 1n certain positions, the starting lgnlting currents would not ignite the cylinders in the proper order in Ign ted during the normal running of the englne, when an ignition-occurs at every 60 of rotation of the crank shaft, but that the current, would leave out the correct cylinder-in the sequence and pass on to the next cylinder on account of the spark gap of the correct cylinderhappening to be in a less favorable condition for theiiassage of an ignition current than the S31 next cylinder. F or this reason the connecting of one and the same starting magneto to two six-cylinder apparatus cannot be recommended. The same difficulties are encountered if, instead ofequipping an aeroplane with a twelve one cylinder of the one engine is ignited together with a c linder of the other engine.

The drawbachs described abovewill be immediately removed if a separate starting magneto 'is connected to each six-cylinder apparatus and both starting .rnagnetos are driven together, for example by a common coupling member such as adriving chain or the like. But this expedient, would be cumbersome and expensive. I

The ob'ect of this invention, is to obviate this cum ersomeness and expense by enabling the sub-divided cylinder groups of an engine with a high number of cylinders, or a pulrality of separate engines, to be started in a reliablemanner by a single magneto.

This object is accomplished lo a device in which each engine, or each cy inder group of an engine with a high number of cylinders, has a main ignition apparatus that o crates durin the ordinary running of tire engine and t at is equip ed with a starting ignition device, and in w ich a single starting magneto is connected. to the various main ignition apparatus through the medium'of a distributer in such manner that the current impulses produced in the starting magneto are alternately conducted to the various main ignition apparatus. The distributedwhich they are loo 1 on the shaft of the magneto armature and co-operates with two fixed distributer contacts which are displaced on a circle by 180.

But if more than two main apparatus or magnetos are used the distributer contacts and the rotating distributor member is geared in such manner that whenever the armature of the starting magneto generator has executed a turn of 180 a current impulse will pass intoa fixed distributer contact.

Since an ignition by starting ignition sparks shall still be possible at speeds of the internal combustion engine amounting to 200 to 300 revolutions per second, the number of current impulses produced by the ordinary magneto generators will not suffice in the case of a large number of engines or of engines with a number of cylinders as high as twelve. This difliculty is met by a further feature of the invention which consists, either in driving the armature of the starting magneto by gear-wheels inserted between the crank-handle and the armature at a specially high speed, or in employing flux -directing members that r0- tate between a fixed armature and the magnet pole faces of the magneto generator so as to affect the paths taken by the magnetic lines of force that passfrom the pole faces and through the iron core of the stationary armature.

If, for example, a cylindrical iron shell with two windows or perforations is used as a flux-directing member, four current impulses will be obtained at each revolution of the shell and it will therefore be possible to mount the rotating distributer .member upon the armature shaft, and to arrange around this member four stationary distributer contacts or current-receiving members at angular intervals of 90.

A manner of carrying out the invention is diagrammatically illustrated in the drawing in which a twelve cylinder engine is represented with its cylinders divided into two groups. For convenience of illustration the one group of six cylinders is shown above the other group. The upper group is associated with the normal or main ignition apparatus A and the lower group of cylinders is associated with the main ignition apparatus B. These main ignition apparatus, of.

which the distributers only are shown, comprise starting ignition devices which are in themselves known (see German Patent No.

253894;). (An auxiliary brush-fordistributing starting ignition currents, which in standard machines is made in a shape of a nickel point from which sparks jump to the stationary distributer members, is arranged to lag behind the brush that distributes ignition current during the normal running of the engine.v Hence the starting ignition.

current is always only able to pass through a normal ignition apparatus into the particular explosion cylinder whose piston has just passed its dead point position) In the drawing the secondary winding 'D, and the distributor E, which is a feature of the invention, represent the starting magneto generator C which is arranged to be driven by a crank handle (not shown). The

end of the secondary winding D which is not connected to earth leads to the metallic sparking member f that rotates with the armature shaft of the starting magneto. Fixed in a stationary distributer disk composed of insulating substance are the sparking points g and h. The distributer point 9 is connected to the lagging point i of the normal or main ignition apparatus A, and the distributing point It is connected to the lagging point is of the main ignition apparatus B.

The device operates in the following manner: At every half of a revolution executed by the starting magneto generator C when turned by its crank handle, a current impulse is produced, and these impulses are distributed through the sparking points 9' and h to the ignition apparatus A and B alternately. By thus compelling the starting ignition currentsto be distributed to the two main ignition apparatus in the described manner, a starting ignition is producedin the engine at every 60 of revolution of the crank, because the gearing of the two main ignition apparatus or distributers is such that each ignition current sent through one distributer into the engine is followed, after the engine crank has turned through another 60, by an ignition current through the other main distributer. In other words, the intervals between the ignition currents sent through any one of the main distributers, amounting to 120 of rotation of the engine crank, are divided by starting ignition currents sent at the middle of each interval through the second main distributer.

if an aircraft or land vehicle is equipped wlth two six-cylinder. engines that are to be started at the same moment, the distributor of the starting magneto is arranged in the same Way, and the two normal or main distributers are connected its-illustrated. If the vehicle has three separate engines or a multi-cylinder engine whose cylinders are arranged in three groups with separate ignltion apparatus, the distributer disk of the tating starting magneto that measles starting magneto is arranged so that the rosparking member 7 is driven at of the speed of the armature. The rotating member f will then move past three stationary sparking points which are disposed around the circle at intervals of 120. In the case of four separately ignited cylinder groups of a multi-cylinder engine the rotating distributing half of the speed of the starting magneto armature and four stationary ,distributer points 90 apart are connected to the laggin current-transferring or sparking points 0 the four normal distributers. I

It may happen that the cylinder groups of an engine are still to receive starting ignition current when the speed ing the operation of starting has reached 200 to 300 revolutions. vIn order to produce the large number of current impulses in the would then be requlred per minute, the armature of the same would have to be driven at an extraordinary high speed, especially if more than two cylinder groups'are to be dealt with. This can be accomplished by a step-up gearing ar ranged between the crank handle and the armature. A preferred method of producing a high number of impulse consists in making the armature stationary, and arranging a rotating, slotted, iron, between the pole faces and the armature of the starting magneto. groups for instance the cylindrical fluxafiecting shell would have two slots and the current-transferring member 7 would be arranged to rotate with it.- This member would then receive four current impulsesin each revolution of the shell.

The scope. of theinvention is not limited to systems shown in the German Patent No.

253894, but also includes other systems if member f is driven at oneattained durfiux-afle'cting shell- With four cylinder applied in the sense of the above description.

I claim:

1'. Groups of cylinders of an internal com-' bustion engine or engines, each group having a separate normal ignition apparatus with a normal ignition current distributer, in combination with a starting ignition device comprising a starting current distributing member in each normal .distributer, a single starting magneto generator for generating starting currents, and "an auxiliary distributer for alternately transferring cur-- rent impulses produced by the startingmagneto generator to the said'various distributing members in the normal distributers.

2. Groups of cylinders of an internal combustion engine or engines, each group having a separate normal ignition apparatus with a normal ignition current distributer, in combination with a starting ignition device comprising -a starting current distribut ing member in each normal distributor, a,

single starting magneto, generator for generating starting currents, spark plugs in the said cylinders, connections between the distributers and the spark plugs, stationary current-receiving members each individually connected to one of the said distributing members in a normal distributer, an auxiliary current-transferring member rotating past the said stationary current-receiving members, and a connection between the said generator and the said current-transferring member. 1

In testimony whereof I have aflixed my signature in presence of two witnesses.

MAX SCI-IAFER.

l/Vitnesses;

MAX LIBLIERs, J. Monron MEYER.

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