US1389646A - Ignition system - Google Patents

Description

D. B. HUGHES.

IGNITION SYSTEM.

APPLICATION FILI-:n APR.2. 1910.

1,389,646. PatentedSept. 6, 1921.

2 SHEETS-SHEET1.

D. B. HUGHES.

IGNITION SYSTEM.

APPLICATION FILED APII.2. I9Io.

1,389,646. PatentedSept. 6, 1921.

2 SHEETS-SHEET 2.

f UNITED STATES PATENT ol-FICEL DOW B. HUGH, OF CLEVELAND, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, T MOTOR IGNITION & DEVICES COMPANY, A. CORPORATION OF WEST VIRGINIA.

i IGNITION SYSTEM.

.Specification of Letters Taten't.

Application led April 2, 1910. Serial N0. 553,111.

To all wwm it may conce/m.:

Be it known that I, Dow B. HUGHES, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Ignition Systems, of which the following is a full, clear, and exact description.

This invention relates to the ignition systems for explosive or internal combustion ennes. One of the objects of the invention is to provide anignition system which has a very highy eiciency and will cause complete or total ignition of the explosive charge conl tained in the cylinder of an engine.

A further object is to provide a system which is more economical in the electric energyor wattage expended in establishing an igniting arc, than the systems Yemployed heretofore. Y

A still further'object is to provide a system which is inexpensive and easy to assemble and maintain 1n good working condition, and which permits' the usel of a magneto which lis wound for low voltages only and is otherwise simple in construction and inex.

pensive to manufacture.

In -carryingout my 1nvent1on,.I provide a system inclu ng a source of current, preferably in the form of a magneto having a low voltage winding, and which is adapted to supply to the spark plug or plugs lowv voltage current which produces an arc of high heat value and of sufiicient duration to secure complete or total ignition or combustion of the combustible charge. Under normal conditions, the voltage of this magneto is ,insuiiicient to establish the arc and therefore to obtain the arc at the generated voltage,'I provide means for temporarily reducing the resistance of the air gap between the spark electrodes. This is preferably accomplished by sup lying to the electrodes a current of high requency and high voltage, this current formin an arc which 1s of low heat value vbut whlch reduces the re-` sistance of the air gap to an extent suchthat an' arc of 'high heat value may be established by the magneto.

In the preferred embodiment of my .invention the magneto armature winding 1s permanently connected to the spark plugs and provision is also made for periodically forming a local or short circuit through a portion of the winding and then openingthe same, for the purpose of charging and discharg- Patented Sept. 6, 1921.-'

ing a condenser which is utilized for generating high frequenc currents. This is accomplished byl a ma e and l:break device nected to the condenser and the secondary of which `is connected to the spark plug,- a high frequency current is induced in the cir. cuit. of the-spark plug so as to create-the high frequency arc of low heat value which, as before stated, is followed up by the arc o f high heat value due to the magneto current. In a system adapted fora multi-cylinder engine, the condenser may be connected t9 the movablemember of a distributer which distributes the high frequency currents to different low, reactance disruptive discharge coils corresponding to the different y cylinders.

The invention may be further briefly summarized as consisting in certain 'novel com-- binations and arrangements of parts which .will be described in the specification and set forth in the appended claims.

In the accompanying sheets of drawings, I have shown the preferred embodiment o my invention, the ignition system and the mag- .neto which is employed therein being adapted for a fourcylinder four-cycle engine.

Inthe drawings, Figure' 1 isl a vertical sectional view of the magneto, certain portlons -being shown diagrammatically or conventionally for vthe sake of clearness; Fig. 2 A,is

an endA view ofthe same with portions shown in section; and Fig. 3 is a diagrammatic.

View of'the main parts of the ignition system.

o The magneto includes permanent field magnets l0 of the ordinary two poleI type, an

'an armature 11 which is' supported on shaft sections 12 and 13, and which is provided preferably with a single low voltage winding 14. Atone end of the armature is a casing 15 which incloses a pair of' collector rings 16 and 17 which are engaged by brushes 18 and 19 respectively, and at the opposite side of the machine is a casing 20 containing a pair of two-to-,one reducing gears 21-and 22 for a distributer, and a casing 23 which incloses an insulated collector ring 24 mounted on the end of the shaft section 12 and engaged by abrush 25. Said casing 23 also incloses a make and break device, including a cam 26 which is mounted on the shaft section 12 a lever 27 which is pivoted on'the interior of the casing and 1s adapted to be pressed by the cam into engagement with the stationary element 28 ofthe make and break device, this element 28 being connected to the brush 25'by a con ductor 29.

The distributer includes' a shaft 30 on which the gear 22 is mounted and which is provided at its outer end with a rotary distributing arm -31 adapted to successively engage a number of spaced contacts or segments 32, these segments Vand the arm 31 being inclosed within a suitable casing 33 mounted upon the gear casing 20. Supported on the pole pieces' between the legs of the field magnets 10 within a suitable casing 34 is a condenser 35, one terminal of which is connected by a conductor 35a to the brush 19 which engages the collector ring 17 and the Vother terminal of which is connected vbv a` vdiiferent spark plugs 38, four of which are shown in the drawing. It may be here noted that by so connecting the spark plugs to the armature winding, the full voltage of the magneto is at all times impressed on the electrodes of the different spark plugs, but the voltage of the magneto issuch that under ordinary conditions no arcs could be established at the spark plugs because of the resistances of the air gaps. In order, however, that arcs of high heat value may be established at the generated voltage, the resistances of the air gaps are reduced succ essvely at the dierent plugs by impressing on the spark electrodes a high voltage and supplying to the same high frequency curends of the armature winding 14 a tap, and

this I connect by a conductor 40 and by an insulated rod 41 extending through the shaft vdistributer.

vsection 12 which is hollow as shown, to the insulated collector ring 24, which as stated before, is engaged-by a brush 25 electrically connected to the stationary element 28 ofthe make and break device.

The cam 26 of the make and break device isv of the two point type, that is, at each` half revolution of the .magneto armature` it causes the closure of the make and `break device. It will be seen, however, that each time the make and break device is closed a portion of the armature between the tap or point 39 and the round point 36 is short. circuited on itself, the short-circuit connections from the grounded point 36 including the section of the armature winding to the point 39 of the latter, the conductor 40,'insulated rod 41, ring 24, brush 25, brush 28, lever 27 of the make and break device and the cam 26 which is grounded on the shaft section 12.

This circuit just described ,which for con venience'of description may be termed the 'lcal circuit lis connected by conductor 42 to the collector ring 17, which as stated before, is connected by brush 19 and conductor 35a.to one terminal of the condenser 35. the other terminal of which is connected to the rotary arm of the distributer. Therefore, each time the local` circuit is closed, current is generatedltherein, and when it is opened, the condenser which as will appear is con'- discharged with great rapidity, setting up 1n the condenser circuit a high ,frequency cur.

rent of high voltage but extremelyr low and almost negligible amperage, the make and break device serving as a spark gap device across which the condenser is disruptiviely discharged.

' In order that this high frequency current may be emplo ed for creating arcs of low heat value in t e'air gaps of the yspark plugs,'

I employ high frequency or disruptive dlscharge coils 43 each of low reactance or inductance, and one of which will beprovided for each cylinder of the en ne. Each of these coils 43 includes a prlmary winding A 43, one terminal of which is grounded, and

the 'other terminal of which is connected to one of the stationary contacts or segments 32 of the distributer, and each coil also includes a secondary winding 43" connected to one of the spark plugs, each spark plug therefore havingin its circuit the secondary of a disruptive discharge coil, the primary of which is connected to one of the segments 32 of the It will be understood Athat as the distributer arm is rotated, vthe primaries of the coils are successively connected in series with the condenser. The low reactance of the coils 43, issecured by employing coils of few turns and without iron cores.

The parts are so'arranged and operated that when the poles of the armature sweep into the magnetic field of the magnet, and

infact at each half revolution of the 'armal ture, with the parts constructed and arranged as here shown, the make and break device is closed, short circuiting a portion of the winding so that a current is generated in this portion, and vimmediately after. the short circuit is opened. When this occurs,

`.the rotating arm of the distributer is in engagement with one of the contacts or segments of the distributer grounding the condenser through the primary of one of the induction coils. The opening of the short cir#V cuit at this time causes the condenser to be make and break device 'therefore serving,

when opened, as a spark gap device. A high frequency current is therefore induced in the secondary of the coil, and-this inducedhigh frequency current of high voltage and low amperage passes to groundy through the spark plug, creating an arc of low heat value. This arc reduces the resistance of the air gap of the spark plug to an extent such that an arc of hlgh'heat value is established suicient duration to cause (complete ignif by thecurrent of the magneto at the voltage generated therein, -itl being understood that when thearc of low heat valueoccurs, the.

armature is in a position suchfthat the maximum voltage of the magneto is generated in the armature winding. This are of high heat v alue which follows immediately after the arc of low heat value, is partly sustained .or carried by the high frequency arc and continues at the spark plug until the .armature poles sweep outof the magnetlc vheld,

or until the voltage drops from its maximum value to'a value such that vit is Aunable to maintain the arc. This arc is, however of tion of the charge-in the cylinder.v The arc of low heat 'value followed b an arc of high` heat value occurs successive y at the different spark plugs as the armature and distributer are rotated. V-

In this manner an arc of hlgh 'heat value and of suiicient duration is obtained with a' small expenditure of electrical energy,' as compared withthe expenditure which takes place with the systemsthat are generally" jemployed.v At the same time,4 it is a-very simple matter to wind the armature,4 inas-l much as there is onl a single winding, and" no high voltageins ation need be provided.

The system is otherwise inexpensive toy manufacture and assemble, and'is very reli able, particularly .as there islittle danger of" ythe spark plugs the insulation being-broken down or of a short-circuit accidentally taking place at anyt point.

will be understood of course thatl my invention is not limited in its application to ignition systems for any particular number4v of cylinders; it may be employed with advantage in` any type of engine and with any number of cylinders.

I do not desire to be confined to the exact details of arrangements shown, but aim in my claims to cover all modifications which do not involve a departure from the spirit and scope of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Pat- A ent is:

1. In an ignition system, spark electrodes, means for supplying to the electrodes high 4frequency current of high voltage so as to form an arc of low heat value and for supp lying to the electrodes a current at rela- .tively lowvoltage so as to form an arc of high heat ',value which follows after the arc lof low heat value, comprising a gen# erator having an armature winding, means for forming a local short circuit for the armature winding and for opening the short circuit, a condenser and a' disruptive discharge coil, the condenser being connected to said circuit in series with the primary-of the coil, and the Ielectrodes being connected to the armature winding in Aseries with .the secondary of the coil.

2. .In an ignition system, spark electrodes,

Qa generator connected to the electrodes, a make and break device, and connections between-the latter and the winding of the generator for -form' voltage when 'said' circuit is ,closed and opened, 'and' a disruptivev discharge 'coil having a primary' connected to said circuit in series with the condenser and a secondary connected to the generator vin series vwith the electrodes, whereby a` high frequency current is linduced'in the electrode circuit causing an arc of low vheat value to be establishe 3. In anignition system, a plurality ,of spark plugsa generator having anar-mal a short circuit for the vwinding and for lnterrupting thesame, a vcondenserV connected to sald circuit and generating a high frequency current at a high rlll ture winding connected to the electrodes ofso as to impress on the same a voltage whicheis normally 'insuicient toform arcs at vthe same,' and means for supply'inghigh frequency currents to the electrodes of the spark plugs so as to reduce the 5 resistances of the air gaps of the latterv comprising a vmake and. break device, an connections between the latter and the'arma-` ture winding for forming alocaljshort cir.-`

cuit through the' latter, a-cOndenSer, a ,dis tributer, said condenser havlng one terminal connected to said circuit and the other terminal connected to the movable member of the4 distributer, andv disruptive discharge coils having primaries connectedto the stationary segments of the distributer, Wherethey are alternately connected in series with the condenser and having secondaries each connected to the generator in series with one of the spark plugs.

An ignition system comprising a source of current, a spark plug, means receiving current from said source and producing anl oscillator discharge of high voltage, connections or subjecting the spark plug to the entire oscillatory discharge to initially establish a spark at the plug, and connections between' the source and the spark plug through which current received from the source is supplied directly to the spark plug following the initially established spark.

5. An ignition system comprising a source of current, a spark plug, means receiving current from said source -for producing va disruptive discharge of high voltage, con-A nections for subjectingthe spark plug tothe entire ,disruptive discharge for initially establishing a spark at the spark plug, and

g other means for supplying current received from the source to the spark plug following the initially established spark.

6. An ignition system for internal combustion engines comprising as a source of current a dynamo electric machine, a spark plug, means receiving current from said source to establish a spark at the spark plug, said means including a path in electrical circuit with said source for delivering current generated by said source through the spark `plug after said spark has been established.

7. An ignition system comprising a source of current, a spark plug, means receiving current from said source for producing an oscillatory discharge to'nitially establish a spark to the spark plug, lsaid means including a path in electrical circuit with said source :for delivering current generated by said source through the spark plug following the initially established spark.

In testimony whereof, lI hereunto affix my signature in the presence of two witnesses.

DOW B. HUGHES Witnesses: H. R. SULLIVAN,

A. F. Kwis.

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