US1248828A - Ignition device. - Google Patents

Description

UNITED STATES PATENT ornroil.

BURNS DICK, OF ST. LOUIS, MISSOURI, ASSIGNOR TO WAGNER ELECTRIC MAN'UFAG- TUBING COMPANY, OF ST. LOUIS, MISSOURI, A CORPORATION OF MISSOURI.

IGNITION DEVICE.

Specification of Letters Patent.

Patented Deo. 4, 1917.

Application filed July 19, 1915. Serial No. 40,601.

To all whom it may concern:

Be it known that 1, Bonus DICK, a subject of the Kin of England, residing at the city of St. Louls, State of Missouri, United States of America, have invented a certain new and useful Ignition. Device, of which the following is such a full, clear, and exact description as will enable any one skilled in the art to which it appertains to make and use the same,"reference being had to the accompanying drawings, forming part of this specification.

My invention relates to ignition apparatus for lnternal combustion engines, and more particularly to improved means for automatically causing the maximum explosion pressure to occur at an efficient point of the crank revolution under all load conditions.

The timing of the ignition spark and therefore the time of occurrence of the maximum explosion pressure has heretofore, so

. far as I am a-Ware,'been placed. either under the direct control of the operator or driver, or has been made dependent Onthe speed of the engine. When placed under the dirent control of the driver, the timing of the spark is usually accomplished by 'IDOVlIlg a lever operatively connected with a part of the timer and arran ed to move said part with relation to anot er and generally sta 'tionary portion of the same apparatus. When made dependent upon the speed, the

movable part of the timmg apparatus is placed under the control of some form or ccntrifugal governor driven by the engine. In the'apparatus herein described, I provide a plurality of spar-h gaps, locate them at different distances from the main body of the compression chamber, and so constitute the electrical circuits within which said s ark-gaps are located that the one nearest the mam body of the compression chamber will be efi'ective at low cylinder compressions While that farthest away from said main body. will be effective at high cylinder compressions. This arrangement yields the'de sired results by virtue of the facts that at a irer. speed the torque varies with the cyl indcr compression, that the resistance of a spark gap increases with the compression, and that the rate of flame propagation decreases as the distance of the effective spark' gap from the main body of the compression chamber increases.

In the accompanying drawings, Figure 1 diagrammatically illustrates an embodiment of my invention. Fig. 2 shows a modification. Fig. 3 illustrates one form of a spark plug provided with a plurality of spark gaps in accordance with the invcntiom Referring to Fig. l, the compression and explosion chamber 2 otthe cylinder 16 is provided with a pocket or ignition chamber 3 within which are located spark terminals forming two spark gaps 4 and 5, of which .4 is placed in close proximity to the main body of the c-:..=mpression chamber 2, while 5 is located back in the pocket 3. Both of these spark gaps are in circuit with the high tension winding 7 of an ignition coil, the primary or low tension winding 8 of which is connected in series with the battery 9 and the interrupter 10. The interrupter is controlled by the spring 12 and is actuated by the cam 11, driven by the engine, to break the primary circuit in the usual way at the contacts 13, 14. The terminals forming the spark gap 4:, whiph is placed near the main body of the explosion chamber 2, are directly -connected to the high tension winding 7 of the spark coil, but the terminals forming Jtlie spark gap 5, which is removed frorlrvthe mam body of the explosion chamber, are connected to the high tension winding 7 through. air-gap 6 placed outside of the cylinder 16. The magnitudes of thespark gap 5, and of the air-gap 6, and that of the spark gap 4', are so chosen that when all of them are subject to atmospheric pressure, 01' when galps 5 and 4. are under the influence of low cy inder compressions, the spark, followinc ideal driver is-supp'osed to achieve by mamis, with increasing mechanical compression within the cylinder, and for reasons hereinafter pointed out, there may be a time when sphrks will be produced at both spark gaps, but, after the mechanical compression produced within the chamber 2 has further in: creased, the spark gap 1 will become dead and the spark gap 5 alone will be effective. When spark gap 1 is effective, the rate of flame propagation will be rapid and the explosion pressure will occur with n a very short time after the separation of the contacts 13 and 14;. When the mechanical compression has increased to an extent suflicient to make the spark gap 4 ineffective and to render spark gap 5 active, the rate of flame propagation will be considerably slower, due to the'fact that spark gap '5 is located. deep within the pocket 3 and therefore at some distance from the main body of the chamber 2. The rate of flame propagation being slower, a longer time interval will elapse between the separation of the contacts- 13, 14' and the production of-th e maximum explosion pres mre. These conditions correspond j to a retardation of the spark with increasing torque, and therefore, achieveautomatically the results which an ual' manipulation of: the spark timing lever. It has beenfoundthat the resistance of a given spark gap increases wlth the pressure 7 of the medium withinwhich a is located, and it-is this fact that I make'use of .to 'make the spark gap 4 ineffective and to render the] spark gap 5 effective at the higher cylinder To this end all of the 1mcompressions. v 'pedance' of the circuit wlth ni which spark gap dis located is concentratedin said spark gap itself,- whereas the impedance of the other spark gap circuit is divided between the spark gap 5. and the air-gap 6. Under these conditions an increasein'cylinder compressi'on will increase all of the impedance inthe circuit-of the spark gap 4:, but will.

only increase a part'of the impedance 1n the circuit of the spark'gap5, since a por-,..

tien of that total impedance, re sented by' the. resistance of the air-gap is located outside of, the cylinder and is only sub ect to the atmospheric pressure, which 18 practically "constant.-

Speaking generally, an impedance is ex pressed'as r z- (I -F where rstands for the ohmic resistance and w for the react'ance, which maybe "ositive' (inductance) or neg-atiye (cap impendance, therefore, fility'cpn ist pure 1 ohmic resistance, or of pure 1n uctan-ce or of pure capacity, but the hamlet r cases are not met within practice, for so'm ohm1c resistance is "almost always present, In the modification shown in Fig. 2, the external air-ga 6, within the circuit of spark gap 5 whic is located at some distance from the main body of the explosion chamber, is 'replaced b a positive reactance or inductance clamped between it and a cap The sul'ator 18'supports'the 'rod'21 in'ca sed in an insulator 20 which fits loosely into a cen-' tral opening through the insulator'18, passes through the insulatingv washer 25 and reaches into the insulating washer, 26. projection'of the insulator 20 rests on the lower part of the insulator 18.1-All upward movement of the rod 21 is revented; by a distance piece 23 and a' was er 22"clajmped under the head of the rod 21. A"ni1t"27,

which screws onto the upper part of the rod 21, presses the washer 22, the distance piece 23, the insulator 9-0, and the insulating Washers 25 and 26 against the'insulator holding all of these together with the foe 21 in a fixed' position relatively to the insulator 18. Formed integralwiththe metal washer 22 is a sparking electrode 24, which forms the spark gap 4 together with the in nor Wall of the spark plug housing 17. l A

thin metal c linder 31 is located between the insulators 1 and 20. At its lower end it carries the sparking electrode 32 which I -passes through suitable opening provided new insulator 20 and forms the spark gap 5 together with the inner wall of the spark plug housing 17. Connected to the upper end of the conductin tube 31 is the spark gapelectrode =33. whic passes out of the-in sulati'ng b0dy18 through a suitable opening therein and reaches' u wardgifitoan opening '6 provided in the'lnsuleting washer 25.

Clampe d between the in'siiliihing washers 25.-.

and 26 is a conducting .late 30 provided with a spark gap-jeledt'ro e reaching down-i washer 25. Clamped between the nut 27 and the thumb nut 29 is a'terf ninal.28which connects with the spark electrode 24;,

ward into the opening 6 of-the insulating" through the nuts 27, 29, the rod 21, and the washer 221 The, central openings in the insulators 18, and 20 are sealed with a suitable compound, so as to prevent the escape. of gases from the cogr'hustmn chamber 2; The

terminals 28 and- 3 0 are both connected to 3 one end of the secondary 7. of the ignition coil, the othepiend' of which is grounded. The primary 0 this coil 8 is in circuit with the battery 9 and the mechanically-operated} interrupter contacts 13, 14. It is seen that" this spark plug providestwo spark gaps; lo-

cated inoperative relation with regard to neeaze the ignition chamber The longer of these spark gaps is located at l, in close. proximity to the main body of the cmnbnstion chamber 2, wlm'reas the smaller gap 53 is located deep within the pocket 3 formed by the housing'oi': the spark plug. The larger spark 'gap l directly connected to the .oncary 7, whereas the smaller spark 5 is separated from the secondary T by the auxiliary gap located in the opening (3 of the insulating; washer "l second. gap is exposed to atmospheric pres-sure only, whereas the spark gaps 4: and 5 are subject to whatever pressure may exist within the combustion chamber 2.

It will be understood that more than two spark gaps may be provided for within each cylinder. Such spark gaps suouid be located at different distances from the main body of the explosion chamber, and the total impedances of the various spark gap circuits and the portions of said impedances which are located outside of the cylinder, should be so chosen that at low fuel pressures ignition s' arks are. )roduced at a snark a") .ilaccd l r; l

near the main body of the explosion chain her, while at increasing fuel pressures said ignition sparks are produced at spark gaps located farther and farther away from the anain body of the explosion chamber.

Having. fully described my invention, What I claim as new and desire to secure by Letters-Patlent of the United States is:

1. In an internal combustion engine, the combination of electrodes forming a. plurality of stationary ignition spark gaps at differentpositions, and means preventing the production of an ignition spark at one of said gaps at the higher fuel pressures.

2. In an internal combustion engine, the combination of an explosion chamber, elec trodes forming a plurality of stationary ignition spark gaps, and means for causing the ignition spark to be produced atone of said gaps at low fuel pressures in the explosion chamber and at a different gap at the higher fuel pressures in said chamber.

3. In an internal combustion engine, the

combination of an explosion chamber, electrodes forming two stationary spur-z gaps for igniting the fuel, said gaps being at difiercnt positions and of different lengths, and an impedance unaffected by pressure in the explosion chamber and in circuit with the electrodes forming one of the spark gaps.

t. In an internal combustion engine, the

combination of an explosion chamber, elec-.

trodes forming two ignition spark gaps, and. an impedance unaffected by pressure in the explosion chamber and in circuit with the electrodes formingone of said gaps.

In an internal combustion engine, the combination of an explosion chamber, elecum forming two ignition spark gaps 0peratwcly located with respect to the explocombination of an explosion chamber, an

auxiliary chamber communicating therewith, electrodes forming two ignition spark gaps, one of the said gaps being Within the auxiliary chamber and farther from the explosion chamber than the other, a source of ignition 'voltage connected to the said elec trodes, and means preventing the production of an ignition spark at one spark gap when the compression of the fuel is high.

7. In an internal combustion engine, the combination of an explosion chamber, an auxiliary chamber communicatingtherewith, electrodes forming two ignition spark gaps, one of the said gaps bein "within the auxiliary chamber and farther roin the explosion chamber than the other, a source of ignition voltage connected to the said electrodes, and means for causing the ignition spark to be produced at one of said gaps at low fuel pressures in the explosion chamber and at a different gap at the higher fuel pressures in said chamber.

8. In aninternal combustion engine, the combination of an explosion chamber, an auxiliary chamber in communication therewith, electrodes forming two spark ps for. igniting the fuel, said gaps bein 0 different length, and the shorter gap lieing situated within the auxiliary chamber and farther from the explosion chamber than the other, and an impedance unafl'ected by pressure in the explosion chamber and in circuit with the electrodes forming the shorter spark gap.

the

-with, electrodes forming two spark gaps for igniting the fuel, said gaps being ofdifi'crent length, the shorter gs. being situatedwithin the auxiliary cliamber and farther from the ex losion chamber than the other, a. source 0 ignition voltage connected to the said electrodes, the electrodes forming one spark gap, being connected to the said'source in parallel circuitwith the electrodes forming the other spark gap, and

an impedance unaffected by pressure in the explosionchamber and in series with the electrodes forming the shorter gap.

10. In an internalcombustion engine, the combination of an explosion chamber, an auxiliary chamber in communication there: with, electrodes forming two spark gaps for igniting the fuel, said gaps being of difi'erres - said electrodes, the electrodes forming one 0 the two subscribing witnesses.

spark gap being connected to-the Sit-1d source ent length, the shorter ga being situated shorter gap and positioned outside the fuel 10 within the auxiliary chain er and farther chambers. v from theeiiplosion chamber than the other, In testimony whereof, Ihave hereunto set a source of ignition voltage connected to the to hand and aflixed my seal in the: presenoe BURNS DICK. [1451 in parallel circuit with the eieet-rodesfor m Kitnesses: ing the other spark gap, and a third spark CARL C. ADAMS,

gap in series with the electrodes forming the HAReY HENzE.

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