US1557566A - Assis-nos to inditstbial kegkaech cobpoha - Google Patents

Description

H. R. DAVIES IGNITION SYSTEM Filed Feb. 21 1921 as :"E- n a 37% INVENTQR. "-5,- rlenry R Dawes ATTORNEYS.

Patented Oct. 20, 1925.

UNITED STATES PATENT OFFICE.

..L RESEARCH CORPORA- TION, OF TOLEDO, OHIO, A. CORPORATION OF DELAWARE.

IGNITION SYSTEM.

Application filed February 21. 1921.

To all whom it may concern:

Be it known that I. HENRY R. DAVIES a citizen of the United States, residing at Toledo, county of Lucas, and State of Ohio, have invented certain new and useful Improvements in Ignition Systems. of which I declare the following to be a full, clear, and exact description.

This invention relates to ignition systems for engines and has particular appliation to the non-seltstarting type of internal combustion engines.

The invention has for an object the provision of means for generating current of approximately maximum pressure during the starting period of the engine.

A further object contemplated is the provision of means for increasing the energy of the ignition circuit at engine starting which shall be entirely automatic in its action. I

Another object also is to establ sh a toll automatic speed adjusting ignition system wherein the employment of movable or vibrating elements are rendered unnecessary.

An important object is to provide a s stem wherein the starting voltage is approximately maximum and which decreases in a more or less uniform rate as the speed increases to an average value most. etiieient for the normal running speed of the engine.

The invention further includes means for automatically decreasing the gradient of normal decrease of the voltage of the system as the speed increases; and novel switch mechanism for effecting simultaneous closure of the ignition and motor circuits while permitting singular operations of those circuits at opening.

Further objects, and objects relating to economics of manufacture and details of construction will become apparent as I proceed yvith the description of the various embodiments of my invention, which may be preferred, illustrated in the accompanying drawings, in which Fi re I is illustrative of the invention a plied to a single unit dynamo-electric mac me normally operative either as a motor or a generator;

Figure II shows the invention .(pplied to a; two unit electric charging an engine Serial No. 446.625.

starting circuit wherein a separate motor and separate generator employed, and:

Figure III illustrates a modification of the arrangement ot Figure II.

Referring to Figure 1 there is shown a storage battery 10, which is designed to furnish current when the engine is not running, for starting and lighting purposes. Connevted to the battery by means of main circuits 11 and 12. through the manual switch 13, is a dynanm-electric machine '14-. the field 150] which is connected in shunt around the dynamo-electric machine or starting generating dynamo, as it may hereinafter be designated. adjacent the main brushes 16 and 17.

The starting generating" dynamo is illustrated as mounted on a shaft 15% which is operatively connecttul to an internal combastion engine (not shown). The starting generating dynamo is designed to transmit power as a. motor through the shaft 18 to start the engine and thereafter to receive power from the engine as generator tor charging and li To obtain these ends the e battery floated across the starting generating dynamo mains as described above and possesses a voltage approxin rely equal to the electric machine.

The ignition system shown oi the high tension type though any other type of ignition would be equally usable in connection with the invention. The primary circuit is illustrated as containing the primary induction coil 19, interrupter contacts 20 and 21, interrupter arm 22, and condenser 23 around the contacts 20 and 21.

One terminal 2 1 of the induction primary is connected through a switch 25 to the main brush 16. The other terminal 26 is connected through the interrupter and condenser to an auxilliary brush 27 which is operatively positioned on the starting generating dynamo armature between the main brushes.

The secondary circuit of the ignition sys tem includes a high tension induction coil 28 connected to ground 29 at one end and connected at the other end through the distributing device 30 with its distributor arm 31 and spark plug circuits 32. to ground 33. The distributor is connected mechanicall to the engine power shaft through the shat 34, which also 0 rates the interrupter cam 35 to open t e interrupter contacts against the resilient pressure of spring 36, which latter bears on the interrupter arm 22.

It should be understood that the showing of the system throughout is diagrammatical. The starting generating dynamo is illustrated as a bi lar machine and merely the commutator is revealed but the various magnetic circuits, pole pieces and armature windings are conventional and are here omitted. Further a four le machine would function as readily in connection with the invention as the 2 pole machine represented. The secondary circuit 15 shown as disconnected from the primary and a four cylinder sparking circuit indicated; but my invention applies as readily to a secondary connected to the primary at 24- and then to ground rather than a direct ground, and any number of sparking circuits might be employed.

In the consideration of the operation of the embodiment of the invention above de scribed the various circuits and switches may be assumed to be initially as illustrated in Figure I with the starting generating dynamo and engine in a state of rest. While in this state the lights 37 or any other miscellaneous load may be supplied, through circuit 38 and switch 39. with energy from the storage battery.

To start the engine the switches 25 and 13 are closed. These switches may be closed simultaneously as more clearly brought out in the modified forms of my invention hereinafter described. or successively, in which latter case preferably the ignition switch 25- should be first closed.

With switches 25 and 13 closed. current from the battery passes into the starting generating dynamo circuits causing rotation of the armature in the direction indicated by the arrow. It is a well known characteristic of dynamo-electric machines that when: operated as a motor the axis of commutation is shifted behind the neutral axis and when operated as a generator the axis ofi commutation is shifted ahead, for a given ditnection of rotation. Since this distortion is due to the magnetic interaction of armature and field: it is evident that tor the shunt machine. considered the maximum angle of lead or lag of the commutation axis occurs for approximately maximum values of current, namely, when the motor is starting under load, or where the generator for a given load is rotating at highest speed;

Assuming that the main brushes 16 and 1? are fixed near the neutral axis it is evident that for the direction of rotation indiouted and: for appropriate values and direction of field flux and current there will a maximum value of voltage between brush 16 and auxiliary brush 27 at starting which voltage willprogressively decrease as the starting generating *dynamd' begins to generate current and its load currentincreases. On the other file load current in the generating starting generating dynamo decreases the voltage between brushes 27 and 16 increases. .75 The characteristics above described are' utilized by connecting the ignition circuit to the auxiliary brush 27 and main brush 16 a! previously indicated. This results in the highly advantageous effect of obtaining maximum voltage in the ignition circuit at: starting when fuel condensation effects in the engine are most disadvantageous carburetion relatively ineflicient. In my Patent Number l,3 72,650 patented: March 22, 1921, I have illustrated the application of the broad features of this invention to a starting generating dynamo wherein both the field and ignition are connected 3 to an auxiliary brush anda main brush,.between which the voltage decreases with speed thus securing a relatively rapid cumiilative decrease of voltage in the ignition cuit. This arrangement is particularly advantageous in automotive traction units} which are subject to continuous variat'ion of} speed; but for some uses particularly 128%,

plied to stationary units, 1' have found arrangement as illustrated in F igure A with the shunt field connected directly across the main brushes. to be more advant us, since the gradient depends almost on the armature reaction variable This? gives a more uniform and less rapid decrease of voltage during the generating period of r the starting generating d name without in any way impairing the e 'ciency of the ma chine at startin y In Figure 11 Thave ill'ustrated' amcdifi cation of my invention as a. plied to 'two unit system, wherein two ynamo e1 Iii; machines, one normally functioning, as a generator and the other as a motor, rsusedi The battery 10 su plies the. liglflfi h through circuit 38 an switch39 as previously described arrangement. q Any type of suitable starting motor It) be utilized but I have illustrated far-1t purposes of this inventiona sari type motor 50 mounted on a five shaflfl W operatively connected with the engine to; 1]} started. One main brush 52 is conn,

54 and the other main brush.55. is connected through the field 53 o one battery fie a nal 5 The generator 58 is shown as a shunt machine mounted on an engine I nected shaft 59. Thereare twomainh through the switch 56 to the batteiystannn 60and 61 and an auxiliary brush 62nd" h a. 1 A. .rjrna iesmaanak hjumjuu .4

xiinuaam a man; His.

shunt field 88 is connected to the auxil ary brush 62 and the main brush 60.

T he generator is connected in parallel with the motor to the battery, the brush ill ha ving a closed circuit. with battery terminal 5- and the main brush (St) is in circuit with the battery terminal 57 through a plurality of switches. I

One of these switches. broadly indicated as 65, is automatic in operation being adapted or closure by the magnetic action of a shunt coil (34. on a movable armature contact arm "i5, which arm carries a contact (56 registerng with a corresponding stationarv contact $7 in the generator circuit. The arm (i?) has permanent electrical connection with a coil 438 also magnetically related to the contact armature 65 and in series with the main circuit from the generator brush (50 to the bat tery terminal 57.

The function of this switch 3 is to close the contacts (36 and 67 when the voltage of the generator has acquired a predetermined value suitable for charging the battery it) and to open the contacts 66 and 6? when the generator voltage has decreased to a point where the combined magnetic effects of both shunt coil 64 and series coil 68 fails to main tain closure against the retractive action of spring (as, an arrangement preventing contact chattering.

The switch 70 has a manual contact arm 71 adapted to effect closure of the main generator circuit and also of the ignition circuit as will be hereinafter set forth. The arm 71 is designed to move freely in a slot 72 cut in an operating handle 73 fixed to the motor switch arm 5(3. spring 'i"-l tends to maintain the switch 56 in a normal open position as indicated in the drawing and in this position switch 71 may be either opened or closed because of the slotted connection to the handle 73. However with both switches in open position as illustrated closure of switch 56 will also simultaneously cause closure of switch 71 which dual closure will remain effective until pressure on the handle 73 is removed, when the switch 56 opens leaving the switch 71 closed. Subsequently the switch 71 may be opened either by a continued upward movement of the handle 73 or by direct manipulation of the switch arm.

The ignition unit is similar in all respects to that described in connecton with Figure I. The primary circuit includes the primary iii-- duction coil 5. contacts 76 and 77. contact arm 78, spring 79 and condenser 80. The secondary circuit includes the grounds 81v and 82 secondary coil 83, distributor arm 84. and spark plug circuit contacts 85. The shaft 86 operates the interrupter cam 87 and the distributor arm 84.

One terminal of the ignition circuit is connected to the auxiliary brush 62 and the other terminal is connected to the main hattor circuit heti'veen the switches 633 and 70. When th Sa'fliCil 63 closed therefore. both the generator field 88 and ignition are con neeted in parallel to the hrushes and subjected to the same armature reactive eti ec in tlcscribinu the operation oi the system illustrated in ..igiiie it may be assumed that the engine is at rest and the various i- ,'it '-hes in the po:' ons shown. Compressing the s it) closes the motor circuit and a circuit n the battery terminal 111 '71 primary igniature windings and brush .3 c to batt terminal 'Ilhereupon the ig :i-on devices and motor are energized and the engine starts up under its own power.

As the engine speeds up the directly connected generator builds up a voltage which closes the switch 63 at approximately the battery voltage. Current then passes from the generator through the switches 63 and T0 to the battery and charging of the same begins. Simultaneously on the closing of the switch 63, ignition current is supplied the ignition system from the generator.

The particular tures of the arrangement of Figure ll are that current for ignition is initially supplied as battery voltage and with no armature reactive effects. but that as soon as the generator functions, which is very shortly utter the engine is started, a cumulatively varying voltage gradient dependent on at least two variables is present. One of these variables is th main line voltage which is diminished with increase of speeds because of armature reaction. therehv affecting the voltage oi the ignition circuit. The second variable is the generator voltage on the ignition circuit which diminishes with increase oi generator or engine speed or with increase of load as indicated with reference to Figure I. These factors combine to produce a relatively rapid voltage drop characteristic on the ignition circuit, subsequent to closure of the automatic switch.

The arrangement oi Figure IT has been found iiarticularlv acvantaecous when used in connection w th small capacity batteries subject to more or less continuous charging conditioi'is such as occur in automotive vehicle or railway cars. Under high speed conditions charging proceeds at a n'iininnun rate and may in tact entirely cease the auto matic switch breaking the circuit. Similaz ly at low speeds the switch ("13 atitoniaticalh opens. But between the extremes of speed the switch 63 is closed and the generator Furnishing ignition and cliarp ii'ig current. the charging current being of course most etlective. at the lower speed ranges. In this way gvercharging of the battery is prevcntet.

tion circuit.

Ill)

In the modification of Figure III the same units and circuits are utilized as shown in Figure II with the addition, however, of a resistance coil 90 in the primary ignition circuit.

The obfect of the resistance 90 resides in the necessity in some instances of providing in a system such as illustrated in Figure II means for diminishing the ignition voltage in the lower generator speed ranges without at the same tim correspondingly decreasin the ignition voltages at the higher speer ranges to an inefficient value. A resistance coil with a high temperature coefficient such as iron has if properly designed relatively high resistance for large current but small resistance for small currents: and the use of such a device tends to flatten out the ignition voltage curve at lower speed ranges without diminishing the effectiveness of the high speed ignitionand armature reactive influences described in reference to Figure II.

I am aware that the specific embodiment of my invention herein described and illustrated are subject to variation without dcparting from the spirit of the invention. and, therefore, I desire to claim the same broadly as well as specifically as indicated by the appended claims.

I desire to claim as my invention:

1. In an ignition system for gas engines. the combination of a dynamo-electric machine having main brushes and an auxiliary brush; a shunt field connected to the main brushes: an ignition circuit connected to the auxiliary brush and one of the main brushes: a storage battery connected to the ignition circuit and to the dynamo-electric machine for supplying current to the dynamo-electric machine to operate the same as a motor, and to receive current from the Y is increased.

2. In an ignition system, the combinatiofl f of a dynamo-electric machine having a, oom i mutator, main brushes. and an auxiliary" brush between said main brushes a shunt field connected to the main brushes of dynamo-electric machine and an ignition ctrcuit having one terminal connected to of said main brushesand the other tcrminol connected'to the auxiliary brush, the voita of the machine between the wuxiiiary br and that one of the main brushes to which. the ignition is connected, tending to dimin-fj ish with increase of machine speed.

3. In an ignition system, thecomhination fl of a dynamo-electric machine having main brushes and a third brush; a shunt fish; a.

. i 4. The combination of a dynamo-electric l! machine, having a field circuit: an ignition. circu t: and means dependent on armature reaction for diminishing the voltage on ignition circuit only asthe mach'me speed i In testimony whereof, I aflix my sigma? ture.

HENRY R. DAVIES;

Images