US2494749A

US2494749A - Electronic ignition and generator

Info

Publication number: US2494749A
Authority: US
Publication date: 1950-01-17
Anticipated expiration: 1967-01-17

Description

Jan. 17, 1950 w. F. FAGEN ET Au.

ELECTRONIC IGNITION AND GENERATOR CONTROL APPARATUS Filed April 25, 1945 Patented Jan. 17, 1950 ELECTRONIC IGNITION AND GENERATOR CONTROL APPARATUS William F. Fagen, Indianapolis, Ind., and Charles W. Klug and Arthur C. Allen, Chicago, Ill., assignors to Stewart-Warner Corporation, Chicago, Ill., a corporation of Virginia g Application April 23, 1945, Serial No. 589,806

(Cl. 29o-41) 8 Clalml.

The open air contact is subject, however, to very serious defects, the most prominent of which, of course, are actual mechanical wear, and oxidation due to the combined effects of heat and air. It has, therefore, seemed desirable to produce a 'system in which the excellent characteristics of the thermionic tube in respect to making and breaking contact may be made use of. Among these characteristics are freedom from variation in qualities due to change in barometric pressure, long trouble-free life with little or no deteriora` tion until the end-point, extreme reliability of operation, and perfect flexibility of control.

The existing automotive systems make use of the storage battery or accumulator in conjunction with an electro-mechanical generator connected to the internal combustion engine by means suitable for maintaining the necessary power relationships for charging the battery. By virtue of the fact that thegenerator is mechanically connected to the internal combustion engine a variable voltage is generated which must be controlled by means calculated to limit the charging current. This means may, in the commonly used systems, consist of a simple compound wound direct current generator, the series winding of which provides the rising characteristic with load and the shunt of which is controlled by external means to produce the flat voltage characteristic, with respect to angular velocity of the mechanism. The external shunt field control means most often consists of a system of contactors so arranged as to reduce the controlled field excitation as-the voltage generated across the armature rises.

In the system of the present invention, this control is effected by means of a grid-controlled, gas-discharge tube so connected as to reduce the field excitation as the generated E. M. F. across the generator amature rises with the angular velocity of the mechanism. This may readily be accomplished by providing a source of alternating voltage which is a .function of the generated continuous'or direct current voltage appearing across the generator brushes. Such an alternating voitage may easily be obtained from the conventional direct current generator by connecting diametrically a pair of slip rings to the generator armature and taking the resultant E. M. F. from these slip rings. This alternating voltage will be very nearly inthe mathematical ratio of .'707 of the generated continuous voltage. The addition of these slip rings to the generating unit is a simple mechanical expedient which adds little to the cost of the machine. This alternating voltage may then be increased by means of a suitable transformer.

It is apparent that in a system oi the foregoing type the frequency of the generated alternating current will be a' function of the angular rotative velocity of the machine. However, in the system of the present invention, variation in frequency may be eliminated as a problem in control of the field excitation, by means of suitable energystoring capacitance.

$5 The generated alternating current voltage is vrectified to produce a proportional direct current control voltage which is utilized to control the generator field excitation to produce a generator output voltage having a flat characteristic with respect to the angular velocity of the machine.

Another feature of the system of the present invention is the vprovision of electronic ignition pulse generating means energized from the alternating current supplied by the generator. This is accomplished by means including a simple rectifying system providing a source of relatively high continuous voltage which may be used with a cold-cathode, grid-controlled, gas-discharge tube in association with a capacitance, charged through a relatively high resistance, and a conventional type of ignition coil, Initiation of the ignition pulse is effected by a voltage source so connected to the timing mechanism as to produce an instantaneous, highly-peaked pulse connected across the grid input circuit. Means for producing this pulse preferably includes a simple ratchet arrangement having a number of teeth corresponding to the number of cylinders in the associated internal-combustion engine and so constructed as to give a change in position of anl element of a magnetic circuit, independent of the rotative speed of the internal-combustion engine, at the desired time. The output of the ignition coil is supplied to the rotor of the conventional distributor.

The present invention contemplates the proy duction of ignition impulses before the engine is actually running by means including a disconnect clutch between the generator and its driving pulley enabling the generator to voperate as a converter, energized from the battery, until the engine speeds up. When this occurs the generator is connected tothe engine and maintains a charge in the storage battery in accordance with desired and predetermined characteristics.

The system of the present invention provides. in addition, a source of alternating current for general purposes at al1 timeswith the additional advantage of a high efliciency of conversion without the inherent disadvantages of vibrating contacts. A whole new field is therefore open in the matter of automotive accessories, such as the radio, induction defrosters, electrical instrumentation, and heating equipment. It is economical,

more reliable, and more satisfactory than the existing types of systems. t In addition, the characteristics of the thermionic tubes are auch that the operation is not subject to the rapid deterioration after adjustment that is 'encountered with the existing mechanical systems.

An important 'application of the ignition system is in high-altitude aircraft operation where the independence of the characteristics of the thermlonic tube from barometric pressure is of vital importance. yIn this connection it may be mentioned that the ignition contacts are replaced after each flight in high-altitude ilying. The tremendous-advantage of a system which is independent of altitude is thus apparent.

One of the primary objects of the present invention is the provision of new and improved voltage regulating and ignition apparatus for internal combustion engines.

Another of the primary objects of the present invention is to provide a new and improved ignition and generator control system for internal combustion engines, and more specifically, a control including electronic devices for controlling both the ignition'and generator.

4, novel generata;- included in the embodiment of the invention-illustrated in l'ig. i.

The control systeme! the present invention is adapted particularly for internal combustion engines of various and especially high altitude aircraft where mechanical ignition and control devices yhave serious disadvantages. The control system inmain: anv ignition system Il; a voltage regulator I2; a generator I4, used also as a converter. and supplying power to the ignition system and voltage regulator; a disconnect clutch II: a control switch Il, which may be the customary ignition switch: and a battery 2l.

The battery may be of any conventional type. One terminal is connected to ground by conductor 22 and the other to one terminal of switch il by conductor 24. The other terminal of the switch is connected by conductor 2l to the terminal 28 of the generator I l.

The generator Il is of novel construction in that it includes means for producing an alternating current control voltage proportional to its angular velocity, which voltage, in accordance with the primary features of the present invention is supplied to the ignition system it and the voltage regulator system l2, of which the latter controls the direct current winding of the generator to give it the desirable "fiat characteristic."

The generator includes the customary high impedance shunt ileld Il, a low resistance series field t2, a commutator 24 connected to the armature winding 3l (of the distributed type). One terminal of the shunt field is connected to ground and the other to terminal .22. One terminal of the series field is connected to the previously referred to terminal 2l and the other is connected by conductor to one of the generator brushes 4t, the other of which is connected to ground.

t0 The alternating current voltage is obtained from thef' armature winding Il, preferably by a pair of slip rings 42 connected to diametrically opposite points ofthe winding. This voltage is proportional to the angular velocity of the arma- A further object of the present invention is to 45 ture and is very nearly in the mathematical ratio provide a new and improved internal combustion engine control system comprising an alternating' current generator.

A still further object of the present invention is to provide a new and improved internal combustion engine control system including a battery and a converter, and more speciiicallya converter having both direct and alternating current windings, the latter of which is utilized for producing a control voltage for imparting desired characteristics to the direct current windings andl for supplying energy to the ignition means.

Another object of the present invention is to provide a new and improved internal combustion a0 engine ignition system of the electronic type having -means mechanically synchronized with the distributor for producing sharp peaked con trol pulses to control the electronic means.

A further object of the present invention is the provision of a new and improved generator for use with internal combustion engines.

Other objects and advantages of the present invention will become apparent from the ensuing description of an embodiment thereof, in the 7 course of which reference is had to'the accompanying drawing, in which Fig. 1 is a diagrammatic representation of one embodiment of the invention; and

Fig. 2 is a schematic circuit diagram of the of .707 of the continuous voltage generated by the generator. 'Ihe slip rings can be added to a conventional generator and the n conn nections can be made both readily and eco- 50 nomically.

55 that the excitation decreases as the angular velocity of the generator increases, the regulator being supplied with the generator alternating current voltage. The regulator includes means u for rectifying the alternating current voltage to provide a direct current control voltage.

It is preferred that the alternating current voltage be stepped up before it is supplied to the rectiiler by suitable means, such as a transformer It. The alternating current control voltage is supplied to the primary winding Il of the transformer by the conductors Il and ,I2 connected to the slip rings 42. The secondary winding I4 is connected to conductors latter is grounded.

The voltage regulator is connected across the secondary winding of the transformer by conductors Il and l2 and it is constructed and arranged to provide a shunt field excitation which Itincludesthepreviouslyreferredtorcctiiier.

type. auch as automobiles, tanks I! and Il, of which the oi the copper oxide type, and grid-controlled.

Y gas discharge tubeiof the 2051 type or o! the M.

type) connected to operate as a voltage regulator. The control grid B6 oi.' the tube is supplied with a negative continuous voltage, very nearly proportional to the generator alternating current voltage, by the rectifier.`

The rectiner is connected to the junction of the voltage divider resistors B8 and 10, of which the iormer is adjustable, and which are connected across the secondary winding by the conductors Il and 82. The other terminal or the rectiiler is connected to the grid 66 of the tube and to the shunt ileld terminal 38 through the parallel connected capacitance 'I2 and grid leak re sister 14. the connection being eiiected by conductor 15. The anode 18 or tube BI is connected to conductor 60 and the cathode 80 is connected to the conductor 18. A filter condenser 82 is connected in parallel with the shunt field winding to render the excitation of the shunt eld free .ci any frequency variation eiects.

The ignition system includes a cold cathode. grid controlled gas discharge tubeS (as of the 631121 type) adapted to be rendered conductive in timed relation with the operation of the engine and controlling ignition pulse producing means. The pulse producing means includes a capacitance 92 and an ignition coil or transformer 94, having a primary winding 86 in 'series with the tube and capacitance and through which the capacitance is discharged at timed intervals. The secondary winding 9,8 of the coil is connected across the distributor it! and the ground connection 58. The distributor may be of any desired or conventional type audit has therefore not been illustrated in detail.

The capacitance 92 is connected to the anode i0! of tube 90 by conductor |04 and the cathode it! oi' the tube is connected to one terminal of the primary winding 96 by conductor |08. The other terminal winding 9,8 is grounded.

The ignition pulse producing means is supplied with energy from the generator I4, preferably, by means including a rectiiier tube ||0 (which may be, for instance, oi the GF4 or 80 type) and a filter capacitance ||2 connected in series across the secondary winding 54 oi the transformer lli. The capacitance 92 is charged through a relatively high value resistor I |4 connecting the anode end of the capacitance to the cathode oi' -the rectifier tube.

The ignition pulses are produced at timed intervals synchronized with distributor operation by control voltage pulse producing means. The latter may take different forms. It may include a sharp peaked pulse voltage producing pickup |20 connected by conductor |22 to the control grid |24 oi' tube 8l operated as by a ratchet wheel |26 rotated in synchronism with the distributor. Each time an ignition pulse is to be produced, the ratchet wheel operates the pickup to apply a sharp peaked control voltage to the grid, thereby to render the tube conductive to eilect the discharge of condenser 92 through the tube and the primary winding of the ignition coil.

In order that ignition pulses be produced before the engine is actually running, the generator is disconnected from its driving pulley by the disconnect clutch IB so that it may operate as a converter and supply alternating current voltage to the ignition system. Under these conditions, the direct current windings of the generator operate as a motor (obtaining energy from the battery) to rotate the armature. thereby to produce an alternating current voltage across the slip rings.

The disconnect clutch I8 is shown between the generator I4 and/the generator driving pulleys |30 and |32, which are interconnected by a belt |34. Thus it normally disconnects the generator from the engine but connectsl the generator to the engine when the latter accelerates to some suitable speed. l

The operation of the system as a whole will now be described. When the switch I8 is open the apparatus is inoperative. vWhen the switch is closed the battery supplies energy to the generator I4, which runs as a. converter to supply alternating current to the ignition system I0 and voltage regulator |2 through the step-upy transformer I6. This alternating current is. of course, available for such other purposes as may be desired. The disconnect clutch I6 is open so that the generator may readily operate as a converter without driving any mechanical load.

When the internal combustion engine is started. as by closing a conventional starter switch, A .the ratchet l|26 operates the pickup to produce control voltage pulses which are supplied to the control grid |24 of the tube 90, with the result that the capacitance 92, which is charged by the alternating current output from the rectifier ignition transformer 94 to produce high voltage ignition pulses in timed relation with the distrib- The alternating current voltage generated by f the generator is a fixed proportion of .the continuous voltage so that, as the latter rises, the alternating voltage will also rise. However, as the alternating voltage rises the negative bias applied to the grid 86 of the voltage regulator tube 8l increases. As the negative bias increases the average current passed by the tube decreases,

thereby to decrease the excitation of the shunt field winding 30. The voltage regulator circuit may be made to level ofi at any desired charging rate and may be designed to produce different excitation voltages dependent upon the requirements of particulanv systems. Adjustment is effected by the adjustable resistor 68 whereby the regulator may be` adjusted, in effect, to an infinite number of control points and the present apparatus is, in this respect also, superior to the usual regulators which have but two or three control positions.

While but a single embodiment of the invention has been described in detail, it should be understood that the details thereof are not to be con strued as limitative of the invention, except in so far as set forth in the accompanying claims.

Having thus described our invention, what we clatim as new and desire to secure by Letters Paten is:

1. An ignition and generator control system for use with an internal combustion engine, including in combination, a generator having a dilrect current exciting ataque 7 winding and means for producing an alternating current voltage proportional to the direct current output of the generator. clutch means normally disconnecting the generator from theengine. a step-up transformer coupled to the alternating current output oi' the generator. means coupled to the transformer for supplying ignition pulses to the engine, means coupled #Q1 the transformer for controlling the excitation of the direct current winding, means connecting the generator to a source of power during starting of the engine whereby the generator is operated as a converter to produce an alternating current output whereby ignition pulses are supplied to the engine, and means including said clutch means for connecting the generator to the engine after the engine has started.

2. An ignition and generator control system for use with an internal combustion engine, including in combination, a generator having a direct current exciting winding and means for producing an alternating current voltage porportional to the direct current output of the1 generator, clutch means normally disconnecting the generator from the engine, a step-up transformer coupled to the alternating current output of the generator, means coupled to the transformer for supplying ignition pulses to the engine, voltage regulator means coupled `to the transformer for controlling the excitation oi' the direct current winding, a battery, means connecting the generator to the battery whereby the generator is operated as a converter to produce an alternating current output whereby ignition pulses are supplied to the engine, and means including said mally disconneetinl the generator from the engine and adapted to connect it'to the engine.

clutch means for connecting the generator to the engine after the engine has started, whereby the battery is charged under the control of the voltage regulator during operation of the engine.

3. A control system as claimed in claim 2,

wherein said ignition and voltage regulatorv means are of the electronic type.

4. An ignition and generator control system for use with an internal combustion engine, including in combination, a generator having a direct current exciting winding and means for producing an alternating current voltage propcrtional to thel direct'current output of the generator, clutch means normally disconnecting the generator from .the engine, a step-up transformer coupled to the alternating current output of the generator, means including rectifying means-coupled to the transformer and a grid controlled gas discharge tube coupled to the rectifying means for supplying ignition pulses to the engine, voltage regulator means including a grid controlled gas discharge tube and rectifying means coupled to the transformer for controlling the excitation of the direct current winding, means connecting the generator to a source of power during starting of the engine whereby the generator is operated as a converter to produce an alternating current output whereby ignition pulses are supplied to the engine, and means including said clutch means for connecting the generator to the engine after the engine has started.

5. A control system for an internal combustion engine, including in combination, a generator adapted to be driven by the engine, means normeans for operating the generator as a motor and for producing an output voltage during the starting of the engine, and means energized by said output voltage for supplying ignition pulses to the'engine.

6. An internal combustion engine control sys'- tem, including in combination, a generator havlng direct and alternating-current voltage outputs for supplying a battery and the engine ignition, respectively, said alternating current output being proportional to the angular velocity ct the generator, means energized by said alternating current output for supplying ignition pulses to the engine. and voltage regulator means ,energized by the alternating current output for controlling the direct current voltage output of the generator. V Y

7. An internal combustion engine control system, including in combination, a generator having direct and alternating current voltage outputs for supplying a battery'and the engine ignition, respectively, means energized by said alternating current output for supplying ignition pulses to the engine, and voltage regulator means energized by said alternating current output for controlling the direct current voltage youtput o! the generator.

8.1 A control system for an internal combustion engine, including in combination, a dynamo electric machine including shunt and series iield windings, a uniformly distributed armature winding, a commutator and slip rings connected to armature winding, means for energizing said series and armature windings with direct current to operate said device as a motor and to produce an alternating current voltage across said slip rings, means including electronic rectifying and pulse producing means for supplying ignition pulses to the engine, and means supplied with said alternating current voltage for controlling the excitation of said shunt field winding.

WILLIAM F. FAGEN. CHARLES W. KLUG. ARTHUR C. ALLEN.

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

UNITED STATES PATENTS Number Name Date 1,234,676 Langner July 24, 1917 1,917,565 Williams July 11, 1933 1,924,462 Bconeld Aug. 29, 1933 1,941,076 Edwards Dec. 26, 1933 1,957,016 Loudon May 1, 1934 1,981,738 McNeil Nov. 201934 1,998,104 Sole Apr. 16, 1935 2,021,396 William'1 Nov. 19, 1935 2,100,076 Gilmore Nov. 23, 1937 2,140,349 Dawson Dec. 13, 1938 2,169,818 Scott Aug. 15, 1939 2,301,440 Nardone Nov. 10, 1942 2,319,835 Williams May 25, 1943 2,338,906 Dausinger Jan. 11, 1944 2,353,527 Touceda et al July 11, 1944 2,367,960

Partt Jan. 23, 1945