US2787649A - Magnetic and a photoelectric system for replacing metallic make and break contacts in automobile ignition systems - Google Patents

Description

April 1957 J. w. BALLARD r-rrAl. 87,

MAGNETIC AND A PHOTOELECTRIC SYSTEM FOR REPLACING METALLIC MAKE AND BREAK CONTACTS IN AUTOMOBILE IGNITION SYSTEMS Filed May 20, 1953 INVENTOR. JAMES W. BA LLA RD ILTON M. MOORHEADJR ATTORNEYS cyl n e -o th e Unitcd States Patent MAGNETIC AND A PHOTOELECTRIC SYSTEM FOR REPLACING METALLIC MAKE AND BREAK -CNACTS IN AUTOMDBILE IGNITION SYS- flT M James W. Ballard, Dayton, Ohio, and Milton M. "Moorhead,'Jr.,Stamford, Conn assignors to The Commonwealth Engineering Company of Ohio, Dayton, Ohio, acorporation of ()hio Application May .20, 1953, Serial No. 356,264 18 Claims. (Cl. 123-148) This invention pertains to an electronic ignition system for automobiles and the likeand especially pertains to an ignition system wherein the conventionalmechanical make and break of the ignition current is replaced bya completelyelectronic system.

Conventional ignition systems of today for firing the cylinders of the automobile engine include essentially, a spark coil, a rotary distributor, breaker points and a battery connected in a well-known manner, that is, the battery and primary winding are connected in series with the breaker ,points and the distributor rotor is connected to the secondary of the coil, while the stator segments thereof are connected to the various spark plugs in the A cam which rotates with the distributqr is used to make and break the breaker'points.

In operation, the primary circuit carries a vvery high camping operation, a large voltage in the nature of 20,000

volts is induced in the secondary coil which in turn is routed to the distributor and thence to the particular spark plug causing firing of the cylinder.

A very serious limitation in the above described system lies in the deterioration of the breaker points. This is due to the interruption by the breaker points of the large inductive-current flowing in theprimary each time these points open. Thusa large arc is vdrawnacross: the; points resulting inpitting and burning thereof. ,The points must be cleaned at frequent intervals and many times complete re cem nt -QQ S NY- in our prior corpending application S. N, 355,106 filed May 14, 195 3, now abandoned,anignition system is disclosed wherein the breaker points are connected in .a low sutr QF Pi PQ iW? i uit. thu a oidin arcing at the contacts. -It would, however, be highly; advantageous to som le e velim nate esems ha cal n a s n t substitute inlieu thereof, a completely electronic system involving no metal to metal contact. This app1icati,on

therefore, is a further improvement on the ignition system dis l se n u .c penrlins. applic ti n cited b ve- Vlliththis in mind, it is a primary object of our invention to eliminatemechanicalcontactors as the-means for interruption of current in an ignition system.

Another object ofour invention'is to replace the mechanical breaker contacts of an ignition system with a completely electronic system.

An important feature of this invention is to control the errand off condition of the primary current in an ignition system by electronic tube means.

Another feature of our invention is to make and break the primary current in an ignition system by :a series of time ma ne ie s- Another feature of our invention is to make and break the primary current in an ignition system by an electronic tube triggered by a pulsed photo-electric device.

These and other objects will become more apparent when viewed in connection with the accompanying dess i t one d aw ng in hi ur is a s hem t r e itrdieer m showing an is- 2,787,649 Patented Ap 195,7

nition .system incorporating the features of this invention;

Figure 2is a modified arrangement of the magnetic system shown in Figure 1;

Figure 3 is a modification of the arrangement shown in Figure 2 showing the use of a rotatinghorseshoetype magnet; and V Figure 4 shows a partial modification'of' the 'system shown in Figure 1 and relates to a photoelectricxdevice which can be substituted at AA in'Figure 1.

Referring now more particularly to Figure -1-of the drawings, the transformer or spark coil 10 isprovided with primary 12 andsecon'day 14 windings. The secondary is connected by the proper high 'voltageca'bles to the rotating arm 16 of distributor118. Each of the stationary distributor segments 20 is in turnconnected to'one of the various spark plugs 22 residingin a cylinder of the engine. This secondary circuit is conventional in most present day ignition systems.

The primary winding 12 of the transformer 10 is connected in series with a high current grid controlled gas type tub-e 24, such as-a thyratron and a'source of voltage 26 for ope-rating the tube. The thyratron may be either a hot or cold cathode gas trio'de, as desired. The plate circuitof the thyratron 24-i's provided with the'usual dropping resistor 28 and with aresistor 30, condenser 32 and neon tube 34, the latter elements being used to control the thyratron and to be explained more 'fully as the description proceeds. I

Connected between the grid and cathode (at points A-A) of the tube'24 is a magnetic pulsing or'triggcring device 36 for the thyratron. It consists of a stationary set of fixed coils 38 corresponding in number and relative location to the stationary segments of the distributor (and of course to the number of spark plugs). These coils are mounted on the periphery of a circular form such that the axis of each coil is radially-disposed relative to the center of the form. Furthermore, the degrees of angular separation of the coils correspond to that of the'distributor segments, for. example, in Figure 1 representing -a six cylinder engine, the coils are spaced 60 from each other as are the distributor segments.

The magnetic pulsing'device is also-provided with'a magnet 40 rotatable about the center of the coils 38 and disposed such that its magnetic'field will cut the coils as it passes by them. This rotating magnet ismechanically connected to the distributor rotor 16 for rotation in timed relation therewith. Adjustment is made between-the distributor rotor and rotating magnet so that at the instant contact ismade between the distributor rotor and a particular stationary segment 20, the field of magnet 40 is cutting one ofthe coils 38. V

Thus it will beseen that eac-h time magnet 40 induces a voltage-in a particularcoil'3'8, this voltage appears across the grid and cathode of tube 24 thereby acting to'trigger or pulse thetube.

Although it forms no part of the present invention per se, a brief explanation of the theoryof a gas filled tube is believed warranted. p

A gas'filled tube such as the thyratron has a constant .voltagedrop, independent of anode current over a wide range of currents. Furthermore, once conduction is begun by pulsing the grid with a positive voltage, current can only be interrupted by reduction of the plate voltage to practically zero even after the grid voltage'has been removed.

-With these principles in mind, the operation of this ignition system is as follows:

Assuming the distributor rotor to be somewhere between two of the segments 20 and thus the magnet 40 to lie somewhere between two of the coils 38, the tube 24 is cut ofi andthe circuit is in a dormant condition. -At the instant rotor 16 contacts one of the segments 20, the field of magnet 40 will have cut one of the coils 38 so as to induce a sutficient voltage therein to fire the tube 24. A heavy surge of current then flows in the plate circuit of tube 24 and thus through the primary winding 12 of spark transformer 10. This sharp rise of current in the primary produces a large inductive voltage in the secondary 14 of the transformer which is routed to the particular spark plug 22 in an obvious manner, thus firing the cylinder.

When the distributor rotor 16 breaks contact with the particular segment 20 and the particular coil 38 is out of the field of the magnet 40 so that the grid voltage is no longer present, some quenching means must be provided to turn off the gas tube 24 so that it may be ready for the next pulsing action. This is accomplished in the following manner: As soon as tube 24 is triggered into conducting, condenser 32 charges through resistor 30 up to a value of voltage equivalent to the voltage of source 26 less the drop across the tube 24. Since the tube drop is comparatively small, this charge is about equal to the voltage at 26. However, a neon tube 34 is connected from one side of the condenser 32 to the negative side of the voltage 26. When the charge across the condenser 32 reaches the firing potential of the neon tube, conduction begins therein and since the drop across a neon tube is negligible, the condenser is eflectively placed across the plate and cathode of the tube. The time constant of the condenser 32 and resistor 30 is such that the neon tube will fire just after rotor 16 breaks contact with the particular segment 20 involved and the magnetic field of magnet 40 is sutficiently removed from the particular coil involved, so that the negative voltage of the condenser placed on the plate of the tube will act to cut the tube otf, thus preparing it for the next cycle.

In Figure 2, there is shown a modification of the magnetic pulsing device of Figure 1. In this embodiment it will be noted that only one stationary coil 42 is provided while there are a number of spaced rotating bar magnets 44. Again the number and spacing of these magnets corresponds to the distributor segments 20. Magnets 44 are mounted on a central rotary axle or shaft 46 which is mechanically connected to distributor rotor for rotation therewith. The coil 42 is provided with an iron core 48 which is positioned so as to be coaxial with each magnet as the latter presents itself in its turn. Thus as the distributor rotor 16 makes contact with one of the segments 20, the field of one of the magnets 44 will be cutting across the coil 42 thereby inducing a voltage therein to be applied to tube 24 at points AA of Figure 1, in a similar manner to that described in connection with Figure 1.

Figure 3 shows a further modification of Figure 2 in that horseshoe magnets 49 are employed instead of the bar magnets 44 of Figure 3. It is believed evident that as the legs of the magnet 49 pass by core 48' of coil 42, a voltage will be induced therein which may be utilized as a triggering voltage, as before. In all other respects, this modification is similar to that of Figure 2. It will be evident that horseshoe magnets could be employed in the embodiment of Figure 1.

Although the above systems have been described such that ignition firing occurs on rendering tube 24 conductive, it is apparent that the reverse operation could be utilized. That is, tube 24 could be normally conductive and the time constant of condenser 32 and resistor 30 adjusted so that tube 24 would cut off when rotor 16 made contact with one of the segments 20. In such a system magnet 40, for example, would be adjusted so as to induce a voltage in the coils 38 during the interval between contact of rotor 16 and segments 20. Thus ignition firing would take place on rendering tube 24 non-conductive rather than conductive as described in the preferred system.

Referring now to Figure 4 a modification of the system for pulsing the tube 24 is shown. This system is identical in all respects to the system of Figure 1 except that the circuit shown in Figure 4 is substituted at AA of Figure 1 for the magnetic pulsing device. This modification consists of a photoelectric tube 50 having a cathode 52, and an anode 54 connected in series with a voltage source 56 and dropping resistor 58. A stationary light source 60 is positioned so that light emitted therefrom will fall on the cathode 52 of the tube. Surrounding the light source 60 is a rotating shield 62 having slits 64 cut 1n the periphery thereof. The spacing and number of these slits 64 correspond to the spacing and number of distributor segments 20, as in the case of coils 38, explained above. The rotary shield is mechanically connected to rotate with the distributor rotor and the positioning of the slits 64 is adjusted so that each time the distributor rotor contacts a segment 20, one of the slits 64 will open a light path or passage between the source 60 and the cathode 52 of phototube 50 as shown in Figure 4. Thus periodic firing of phototube 50 will produce pulses of voltage across resistor 58 which in turn are applied as triggering pulses for the thyratron 24. It will be understood that the size and wave length of light source 60 must be sufiicient to produce enough current through phototube 50 to develop the proper triggering voltage across resistor 58 for firing tube 24. Operation of the modified ignition system of Figure 4 is identical to that of Figure 1 except for the substitution of the phototube circuit and thus further explanation is believed unnecessar Ii should be understood that a photocell, either of the electrolytic or electronic type, could be substituted for phototube 50 and voltage source 56, if desired.

As in the magnetic pulsing system, so also can the photoelectric system operate to cause ignition firing by rendering tube 24 non-conductive rather than conductive. Thus by assuming tube 24 to be conducting, the time constant of resistor 30 and condenser 32 could be adjusted to cut otf tube 24 at the instant rotor 16 makes contact with one of the segments 20 causing interruption of current in the primary and a resultant inductive surge in the secondary. In this modification, the light passages or slits 64 of shield 62 are arranged to permit light to fall oncathode 52 during the interval when rotor 16 is between contact segments 20 and light is shut off when the rotor 16 makes contact with a segment 20. This reverse operation is believed evident without further explanation. Thus it will be seen that basically two systems have been disclosed for breaking the current in the primary circuit of an ignition system, neither of which involves the mechanical make and break or metal to metal contact usually employed. Thus there is no heavy arcing or deterioration of breaker points and as a result, the life of the ignition system as a whole has been lengthened.

While we have discussed and described certain preferred forms of the invention, yet its construction can be modified without departing from the spirit of the invention, and those modifications that fall within the scope of the appended claims are intended to be included therein.

We claim:

1. An ignition system for eliminating the mechanical. interruption of ignition current comprising a spark coil,

said coil being connected to a rotary distributor means and to an electron tube means, electromagnetic means for firing said tube means and being synchronized with said distributor means, and gas tube means connected to said electron tube means for rendering said electron tube nonconductive.

2. An ignition system for eliminating the mechanical make and break of ignition current comprising an induction coil, means for connecting a rotary distributor to said coil, electron valve means connected to said coil, means for switching said valve on in timed relation with said distributor means, and gas tube means for switching said valve off in timed relation with said distributor means.

3. "In an ignition system comprising a source of ignition current and an induction transformer :having primary and secondary coils, and having rotary distributor means I connected to said secondary, an electronic switching means for said ignition current comprising: normally inactive electron tube means connected in series with said primary and .said source of current, means for activating said tube for flow of current therethrough comprising an electromagnetic responsive means synchronously operated with said rotary distributor means, and neon tube means for deactivating said electron tube means in synchronism with said rotary distributor means.

.4. An ignition system having primary and secondary circuits, a rotary distributor means connected to said secondary circuit, said primary circuit including a gridcontrolled normally inactive gas tube means connected in series with a source of ignition current, magnetic induction means connected to the gridof said tube synchronized with said rotary distributor for periodically pulsing said tube into .a conductive state and means connected to said tube ,fordeactivating the same after a predetermined period of conduction, said last-mentioned means comprising a gas tube.

5. An ignition system having primary and secondary circuits, a rotary distributor connected to said secondary circuit, said primary circuit including a grid-controlled gas tube means and a source of ignition current in series therewith, means for switching said tube between alternate states of conduction and non-conduction including magnetic induction means connected to the grid of said tube and rotatable with said distributor and a quenching means connected to the plate of said tube and being alternately operable with said induction means, said quenching means comprising a gas tube.

6. An ignition system for elimination of mechanical interruption of ignition current and having primary and secondary circuits, a rotary distributor connected :to said secondarycircuit, said primary circuit including a source of ignition current, a normally non-conductive grid-controlled gas tube means in series with said source of current, induction coil means coupled to the grid of said tube and magnetic field producing means rotatable with said distributor for periodically cutting said coil means whereby to render said tube periodically conductive, and quenching means connected to the plate of said tube and operable after a predetermined period of conduction in said tube for rendering said tube non-conductive, said quenching means comprising a gas tube connected between the plate of said grid-controlled gas tube and said source of ignition current.

7. In an ignition system including a secondary circuit having a distributor and a primary circuit coupled thereto, said primary circuit comprising an electron tube, a source of ignition current connected in series with said tube in said primary circuit, means for cyclically switching said tube on in timed relation with said distributor including photoelectric means, means connected to said distributor for activating said photoelectric means, and means including a gas tube for cyclically switching said electron tube oft.

8. An ignition system having primary and secondary circuits, a rotary distributor in said secondary circuit, a source of ignition current and a grid-controlled electron tube in series with said source of current, light sensitive photocell means connected to the grid of said tube, a source of radiation and means for periodically directing said radiation toward said light sensitive means in timed relation with said distributor, and gas tube means for deactivating said electron tube.

9. An ignition system having primary and secondary circuits, a rotary distributor means connected to said secondary circuit, said primary circuit including a gridcontrolled normally inactive gas tube means connected in 6 series with a sourceof ignition current, light sensitive electron tube means connected to the gridpf saidtube and means synchronized with said rotary distributor for periodically energizing said last mentioned tube means whereby said gas tube means is rendered active and means including a neon tube connected to said gas tube .means for deactivating the same after a predetermined period of activation.

10. An ignition system having primary andsecondary circuits, a rotary distributor connected to said secondary circuit, said primary circuit including a grid-controlled gas tube means and a source .of ignitioncurrent in series therewith, means for switching said tube means between alternate states of conduction and non-conduction including normally inactive phototube means, asource of voltage in circuit with said phototube means, means for activating said phototube during periodic intervals in timed relation with'said distributor, means in circuit with saidphototube for producing a voltage when said phototube is activated and means for applying said latter voltage to the grid of said gas tube, and gas tube means for deactivating said grid-controlled gas tube after each activation thereof.

11. An ignition system for eliminating the mechanical make and break of ignition current and having primary and secondary circuits, comprising a rotary distributor connected to said secondary circuit, said primary circuit including a source of ignition current, a normally nonconductive grid-controlled gas tube ,means in series with said source of current, means connected to the grid of said tube for producing a triggering .voltage comprising a normally inactive photoelectric tube and a source .of

voltage in series therewith, a light source adjacent said photoelectric tube and means for activating said latter tube during periodic intervals by pulsing said light source periods of said photoelectric tube, and gas tube means to render said grid-controlledgas tube non-conductive after each activation thereof.

12. An ignition system for eliminating the mechanical make and break of ignition current and having primary and secondary circuits, comprising a rotary distributor connected to said secondary circuit, said primary circuit including a source of ignition current, a normally nonconductive grid-controlled gas tube means in series with said source of current, means connected to the grid of said tube for producing a triggering voltage comprising a normally inactive photoelectric tube and a source of voltage in series therewith, a light source adjacent said photoelectric tube, means normally shielding said light source from said photoelectric tube and timed means synchronized with rotary distributor for periodically removing said shield thereby activating said photoelectric tube to produce a triggering voltage for said gas tube and quenching means comprising a neon tube connected to the plate of said gas tube and operative after a predetermined period of conduction therein to render the same non-conductive.

13. An ignition system for eliminating the mechanical make and break of ignition current and having primary and secondary circuits, comprising a rotary distributor connected tosaid secondary circuit, said primary circuit including a source of ignition current, a normally nonconductive grid-controlled gas tube means in series with said source of current, means connected to the grid of said tube for producing a triggering voltage comprising a normally inactive photoelectric tube and a source of voltage in series therewith, a light source adjacent said photoelectric tube, a rotary shielding means for said light source having a plurality of light paths therein, said shielding means connected for rotation with said rotary distributor and operative to periodically activate said photoelectric tube thereby producing a triggering voltage for said gas tube and means comprising a neon tube to 7 quench said gas tube between periods of activation of said photoelectric tube.

14. An ignition system for elimination of mechanical interruption of ignition current and having primary and secondary circuits, a rotary distributor connected to said secondary circuit, said primary circuit including a source of ignition current, a normally non-conductive grid-controlled gas tube means in series with said source of current, induction coil means coupled to the grid of said tube and a plurality of spaced rotary magnets connected for rotation with said distributor for periodically inducing a voltage in said coil means whereby to render said tube periodically conductive, and quenching means comprising a neon tube connected to the plate of said tube and operable after a predetermined period of conduction in said tube for rendering said tube non-conductive.

15. An ignition system for elimination of mechanical interruption of ignition current and having primary and secondary circuits, a rotary distributor connected to said secondary circuit, said primary circuit including a source of ignition current, a normally non-conductive gridcontrolled gas tube means in series with said source of current, induction coil means coupled to the grid of said tube comprising a plurality of spaced coils and magnetic field producing means rotatable with said distributor for periodically cutting each of said coils whereby to render said tube periodically conductive, and quenching means comprising a neon tube connected to the plate of said tube and operable after a predetermined period of conduction in said tube for rendering said tube nonconductive.

16. An ignition system having primary andsecondary circuits, a distributor means having stationary contacts and a rotary contact arm connected to said secondary circuit, said primary circuit including a grid-controlled gas tube means connected in series with a source of ignition current, means connected to the grid of said tube and synchronized with said rotary distributor for pulsing said tube into a conductive state when said contact arm is not in contact with any of said stationary contacts, and means including a gas tube connected to said grid-controlled tube for rendering said grid-controlled tube nonconductive when said contact arm makes contact with any of said stationary contacts.

17. An ignition system having primary and secondary circuits, a distributor means having stationary contacts and a rotary contact arm connected to said secondary circuit, said primary circuit including a grid-controlled gas tube means connected in series with a source of ignition current, electromagneticmeans connected to the grid of said tube and synchronized with said rotary distributor for pulsing said tube into a conductive state when said contact arm is not in contact with any of said stationary contacts, and means including a neon tube connected to said tube for rendering said tube nonconductive when said contact arm makes contact withany of said stationary contacts.

18. An ignition system having primary and secondary circuits, a distributor means having stationary contacts and a rotary contact arm connected to said secondary circuit, said primary circuit including a grid-controlled gas tube means connected in series with a source of ignition current, photoelectric means connected to the grid of said tube and synchronized with said rotary distributor for pulsing said tube into a conductive state when said contact arm is not in contact with any of said stationary contacts, and means including a neon tube connected to said tube for rendering said tube non-conductive when said contact arm makes contact with any of said stationary contacts.

References Cited in the file of this patent UNITED STATES PATENTS 2,053,016 Wilder Sept. 1, 1936 2,169,818 Scott Aug 15, 1939 2,338,906 Dausinger Jan. 11, 1944 2,476,128 Wintsch July 12, 1949 2,552,989 Mayer May 15, 1951

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