US2550026A - Starting and ignition system - Google Patents

Description

April 24, 1951 B. H. SHORT 2,550,026

STARTING AND GNITION SYSTEM Filed May 14, 1946 Patented Apr. 24, 1951A STARTING AND IGNITION SYSTEM Brooks H. Short, Anderson, Ind., assigner to General Motors Corporation, Detroit, Mich., a. corporation of Delaware Application May 14, 1946, Serial No. 669,498

2 Claims.

This invention relates to ignition apparatus for internal combustion engine and more particularly the type of apparatus shown in the copending application of B. H. Short and A. G. Tynan, Serial No. 611,402, filed August 18, 1945, now Patent No. 2,463,123. The apparatus disclosed in said application comprises a source of direct current, a main condenser and an auxiliary condenser charged thereby, a thyratron tube which, upon being rendered conducting, provides a discharge path from the main condenser through the primary of a high frequency ignition coil, and a circuit including the auxiliary condenser, the grid of the thyratron and an ignition timer which at the proper instant causes the auxiliary condenser to ydischarge through the thyratron grid to render it conducting.

One object of the invention is to provide in connection with ignition apparatus, such as the type referred to, means for withholding the application of voltage from the D. C. source to the thyratron tube for a predetermined time following the closing of a main control switch which renders the D. C. source operative to supply voltage to the tube. This time is sufficient for the heating of the cathode of the thyratron. In this connection it is a further object to prevent the use of the engine starter during the interval required to heat the thyratron cathode. If the D. C. source is a vibrator power pack operated by the storage battery and having rectier tubes, the time interval required for heating the thyratron cathode would include the time required for heating the cathodes of the rectier tubes.

A further object of the invention is to suppress the emanation of high frequency disturbances so that the operation of adjacent radio apparatus is not interfered with.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred embodiment of the present vinvention is clearly shown.

The ligure of the drawing is a wiring diagram disclosing an embodiment of the invention.

A's disclosed in the copending application referred to, the ignition apparatus comprises a terminal I connectible with a D. C. source and connected with a voltage divider comprising resistance elements II and I2 connected by a tap I3 and grounded at y. A resistance I4 connects tap I3 with condenser I5 which is grounded. Terminal I0 is connected by resistance I6 with a vmain condenser I'I connected with-primary P of (Cl. 12S-179) a high frequency ignition coil whose secondary S is connected with an ignition distributor 20 for distributing sparking impulses to a plurality of spark plugs, one of which is indicated atv 2I. The charging of the main condenser is from the high voltage terminal I0, resistance I6 and through primary P to ground. The discharge of the main condenser I6 is controlled by a hydrogen lled thyratron tube 22 whose plate 23 is connected between resistance I6 and condenser I'I and whose grid 24 is connected by resistance 25 with ignition timer contact 26 cooperating with timer contact 2'I connected with resistance I4 and auxiliary condenser I5. Tube 22 has a grounded cathode 28 heated by a lament 28a.. A resistance 29 connects grid 24 and resistance 25 with ground.

Suitable electrical dimensions -of the condensers and resistances are as follows:

Resistance II megohms 5 lResistance I2 do .75 Resistance I4 do .'75 Resistance I6 do .1 Resistance 25 ohms-- 2500 Resistance 29 do 25,000 Condenser I5 mf-- .001 Condenser Il mf .02

While the dimensions given have proven satisfactory for certain types of service it may be understood that other dimensions may be selected depending upon the type of service. A satisfactory thyratron tube is type 4G35. The high frequency ignition coil may be constructed in the manner disclosed in the copending application referred to. The operation of the ignition system is disclosed in detail in said application.

Briefly stated, the operation is as follows: Condensers I5 and I'I are charged by applying a suitable voltage from a D. C. source to the terminal Ill. When the timer contacts 26 and 21 are closed, condenser I5 discharges thereby rendering the tube 22 conductive whereby the condenser I'I is discharged through the primary P of ignition coil 30 and a sparking impulse is distributed to the required spark plug 2I by the distributor 20. When condenser I'I is discharged the thyratron 24 becomes nonconducting and cannot be rendered conducting again until condenser I5 is discharged by another closing of the timer contacts.

The ignition apparatus is operable by any suitable source of direct current of sufficient voltage. One suitable source is what is known as a vibrator power pack comprising a power high frequencies.

48a and 41a or with contacts 48h and 41D con-v is caused, to vibrate by currently. The reed l] Y an electromagnet (not shown) having a coil which is intermittently energized and. then def..` energized by a short circuit controlledV by the V reed in the well known manner. For full wave rectification the power pack includesrect/incr,`

tubes 5I and 52 having cathodes 53 and 54 resupply from the battery through the line. The 4 mf'. condenser 11 supplies the demand for low frequency current at point l5 and the .l mf. condenser 13 for certain higher frequency currents; Demand vfcr currents of other frequencies which the upper choke 'I4 does not entirely ridinirnize will be supplied by upper condenser 13. If there is still an unsatisfied demand for transient current not minimized by the lower choke 14, the lower condenser 'E3 will supply it. In

vthis way the long line from the battery to the power-pack is not required to transmit transient currents which would interfere with operation spectively and plates 55 and 56, respectively. 1- I The respective cathodeheater filaments 5l and 58'. of .the tubes are connected respectively with the transformer secondaries 44 and 45. Plate 56' and cathode 53 are connected with the upper endl of secondary winding 43, the lower end of which is connected by wire 59 with a switch contact 66 which at the proper time makes engage-4 mentV with fa .contact t! connected by a wire 52 with a. terminal t3.l iA condenser 64 is connected between .terminal E3 and cathode 54. Alcondenser '65 is connected between terminal 63 and plate 55' which is grounded. Cathode F14-is connected with the terminal Ill. A condenser t5 is connected across ythe terminals of secondary winding 43.

Y,'l'he low .voltage currentY for operating the power pack is obtained 'from the storage battery which is grounded andv which is connected ythrough ammeter 'il'. and ignition switch 'l2v with a chain of concentriccondensers 13 alternating with choke coils 14 connected in series with the switch'l2 yand a terminal l5 which is connected with the 'center taps ofn primary windings 4land 42: rEhe outer terminals ofthe condensers T3. are connected with-a grounded wire 'It'.V A

condenser 'll is located between wire 'i6 and The elements 13, 14 and 7'! ,con-

terminal 15.

nected las shown 'provide for the suppression of emanations from the ignition yapparatus which would Yinterfere with adjacent radio apparatus. The lead. Vfrom the secondary VS of coil 38 to the distributor 2li` may be prcvidedwith a lgrounded shield a. Satisfactory suppression, ofjradio interference has been obtained when the condenser capacities are as follows: Condenser 1l, 4 mf;

uppermost condenser 13, .l mf.;` and the two lowercondensers 13, .7 mf.

"The, reasons why thecondensers 'il and 13 and the, choke 'i4 are effective to suppress interfer- .ence with radio operation are as follows. When the vibratorcontacts kclose and open, the form of the electrical wave in the parts of the transformer primaries is substantially rectangular. These rectangular waves are the resultants of component fundamentalwaves of relatively low frequency andharmonies ofdiierent relatively Therefore. if no Suppressors were. placedin the relatively long line between the battery and the power pack, this line would serve as.an.,antenna which would broadcast waves resulting from the ytransient currents which would occur in the line bylreason of `the components of the rectangular wavesY in the Vtransformer primary. The function of the condensers is to .supply the transient currents as contact l0 l ofl the carA radio.V Obviously, the power pack, its Suppressors, the ignition apparatus, the thernial switch and the-relay switch connected with the powerpack would be closely grouped and shielded. l

v'Ihe'apparatus for withholding the application of voltage to the terminal l0 of the ignition apparatus'until'after the cathode 28;` has' been sufficientlyheated willV now be described. The cathode heater filament, 28a is connected by wire 8.0 Vwith terminall l5." A. wire 8l connects wire .8G `witha contact 82 engageable with a contact Bimounted on the upper wall of a flexible metal bellows 84 whose Vlower wall is provided by va metal plate 85 which insulatingly supports ter,- minals S6 andv 3l connected with a heater coil ,88 located kwithin the bellows 84. Contact 82 is connected by wire S9 with a relay armatureA 90 carrying a contact 9| normally engaging a contact 92 connected by wire 93 with terminalY 81.

Terminalr is grounded. Plate 85 is connected heater'lament 28a' is connected with the battery l0. While the cathode 28 is being heated to the temperature required for proper operation of the tube 22, the power pack cannot supply a voltage to the terminal l0 because a circuit of the transformer secondary winding 43 is interrupted by the separated contacts 6i!A and 6|. While cathode v28is being `heatedvthe heater' within the Sylphonis connected with the `battery through a circuit which includes the `terminal l5, wire El); wire 8l, contact 82, wire 8,9, armature contactr 9i', contact `t2, wire 93, terminal:l 8l', heater 8S and terminal 8E.' By the timev the cathodes 2t Ahave beenV heated sufficiently for proper operation of the tube 22, the air within the bellows 84 will have expanded to such extent thatv contact 83 will Vengage contact 82 vand the magnetr coil 95 will be connected with the battery through a circuit which includes: Terminal l5, wire 8B, wire 8l, contact 82, contact 83, bellows B4, plate 85, wire 94 and coil 9,5. Armature 9i!y will be actuated downwardly to separate con-.- tact El from contact 92 thus Open circuiting the heater coil 88 and causing the contact 60 to engage contact 6I whereupon the pov/er packr 40 `will `be eifective to supply the proper-voltage to the terminal IG. v

In order that the car driver will not inadvertentlyattempt -to operate the engine starter while there is no ignition available, means areprovided for preventing the connection of the storagebattery Vwith thestarting motor until after ignition is available.` For this purpose, Ya control of the connection of the starting motor with the battery includesl aI contactY Il carried vby the armature Sill.A and normally separated from a stationary Various means can be provided for utilizing contacts lili).Y and llllfor controlling the Aconnection .-betweenthe :storage battery andthe starting motor. For example, in a starter system using the accelerator or throttle pedal for causing the battery to become connected with the engine starting motor the contacts and |0| would be connected into a series circuit which includes the following elements: Battery 10, ignit-ion switch l2, terminal l5, wire 09, wire 8|, contact 82, wire 39, armature 90, contact |00, contact |0i, a switch |02 which can be closed by the accelerator pedal only when the engine is not self-operative, a relay coil |03 and a pair of normally closed contacts |04 and |05 which are opened automatically by the cut-out or reverse current relay (not shown) used to control the connection between the generator (not shown) and the storage battery, Therefore, before the cathode 28 has been heated suihciently for proper operation of the tube 22 no current can iiowy from the battery through the relay magnet coil |03. When armature 90 is attracted downwardly after the lapse of time suicient for the proper heating of cathode 23, then the battery becomes connected with the magnet coil |03 through the series circuit which has been described. When this occurs, the armature 509 of the relay moves a contact |07 into engagement with a contact |08 thereby connecting the battery through wire |09, Contact |83, contact I0?, armature |06 and wire ||0 with a solenoid magnet coil of relatively coarse wire and a solenoid magnet coil Il?. of relatively fine wire. The circuit of winding is completed through the starting motor ||3 to ground. The circuit of the line winding ||2 is completed directly to ground. The energization of both windings and i2 is suiicient to eiect left movement of a solenoid armature H4 against the action of a spring H5 to cause a contact ile to bridge contacts and H8 thereby connecting the battery 'i0 with the starting motor H3 through the wire |09, contact Il?, contact H6 and Contact |40. When this occurs, the coil is short-circuitcd, but coil is able to maintain the contacts in engagement since the air gap between the armature H4 and the core, not shown, is relatively small. The left movement of the solenoid armature H4 may be used to shift the starting motor drive which is not shown. When coil l i2 is deer-iergized, 'the spring l is permitted to separate the contact E6 from the contacts EH and. |18 and to disengage the engine starter drive from the iiywheel loi. the engine. Coil ||2 is deenergized when relay coil |03 is disconnected from the battery. This is vaccomplished by the separation of contacts |04 and |05 when the cut-out relay closes to connect the generator with the battery after the engine becomes self-operative, as disclosed in Dyer Patent 2,167,646, and also by the opening of throttlepedal-operated switch |02 in the manner disclosed in said Dyer patent which shows in detail one form ofsuch switch or in the manner disclosed in Dermond Patent 2,324,125 which shows another form of such switch.

While the embodiment of the Ipresent invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted all coming within the scope of the claims which follow.

What is claimed is as follows:

l. Ignition apparatus for internal combustion engines, comprising an ignition coil, a condenser, a power pack for charging the condenser, a thyratron for withholding the discharge of the condenser to the thyratron until the required instant of iring, a timer driven by the engine for effecting the thyratron, a low voltage current source for operating the power pack and for supplying current to the lament of the thyratron, an electric motor for cranking the engine, and means for withholding the application of a voltage by the power 'pack to the plate of the thyratron and for withholding the connection of the current source with the electric motor, for a time during which the thyratron is heated to operating temperature.

2. Ignition apparatus for internal combustion engines, comprising an ignition coil, a condenser, a thyratron for controlling condenser discharge to the coil, a power pack for applying a charging voltage to the condenser and a suitable voltage to the plate of the thyratron, means including a timer driven by the engine for rendering the thyratron conducting, a low voltage current source for operating the power pack and for supplying current to the lament of the thyratron, an electric motor for cranking the engine, and means for withholding the application of voltage by the power pack to the condenser and .to the plate of the thyratron and for withholding the connection of the current source with the electric motor for a time suiicient for the proper heating of the thyratron to operating temperature.

' BROOKS H. SHORT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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