US3150286A

US3150286A - Ignition system for internal

Info

Publication number: US3150286A
Authority: US
Current assignee: Edison International Inc
Publication date: 1964-09-22
Anticipated expiration: 1981-09-22

Description

P 1954 H. P. QUINN 3,150,286

IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES Filed Feb. 9, 1962 2 17/5 l'ribu 'm' (/ase 40 -Open 40 Uur/"en/ f Tfimuyh Pain/s 42 X42 V/ V2 [L m y; q fi A M 4/ 4/ V 4/ hp 2 flnaae l/o/fage V4 V V Spark VOALdge INVENTOR.

BY e wwwmw A7 TTORNE YS United States Patent 3,150,285 IGNTTTDN SYSTEli l FOR INTERNAL (IQM -USTION ENGWES lalsey P. Quinn, Morris Plains, NJEZ, assignor to Tung- Sol Electric line, a corporation of Delaware Filed Feb. 9, 1952, Ser. N 172,193 4 Claims. (Cl. 315-289) This invention relates to an ignition system which provides a high intensity spark at the spark plugs at the time when the breaker points are opened.

The development of new and more efiicient internal combustion engines provides a need for a more eflicient and a more dependable ignition system which can provide hi intensity sparks even though the pressure within the cylinders is quite high. Since the engines of present day automobiles and other forms of internal combustion engines are arranged to fire when a pair of breaker contacts are opened, the present invention is designed to provide the same type of operation, thereby making this system compatible with systems now in use. The invention uses a capacitor discharge pulse for generating the spark. The pulse is provided by a storage capacitor discharging a heavy current through a gaseous discharge device. This system produces a fast rise time and for this reason an intense spark can be produced at the points of a spark plug even though the plug has some leakage resistance.

One of the objects of this invention is to provide an improved ignition circuit which avoids one or more of the disadvantages and limitations of prior art circuits.

Another object of this invention is to provide an electronic i nition system which is compatible with modern day automobile ignition systems.

The invention comprises an ignition circuit for internal combustion engines having a spark plug in each combustion chamber and includes a source of direct current, a primary circuit which includes the power source, the primary of a charging transformer, the primary of a firing transformer, and a transistor amplifier. The transistor amplifier is controlled by a set of breaker points which open and close under control of the movement of the pistons in the engine. The circuit also includes a storage capacitor which is connected in series with a diode rectifier, the primary of an output transformer and the secondary of a charging transformer. The circuit also includes a discharge path which includes the above mentioned storage capacitor and primary of the output transformer shunted by a gaseous discharge device which is controlled to conduct by a control electrode connected to a secondary winding of a firing transformer. The connections are such that the storage capacitor discharges through the output transformer primary at the time when the breaker contacts are opened, thereby providing a spark at one of the spark plugs in the engine coupled through the usual distributor.

For a better understanding of the present invention, together with a specific embodiment thereof, reference is made to the following description taken in connection ith the accompanying drawing.

FIG. 1 is a schematic diagram of connections of the circuit used by this system.

FIG. 2 is a series of graphs showing the variations of certain currents and voltages in the system during its operation.

Referring now to FIG. 1, the circuit includes a source of direct potential 143 which may be a battery, 2. pair of breaker points 11 operated by a cam 12 which is turned by a shaft 13 coupled to the distributor and to the pistons (not shown) the engine. A transistor 14 is provided for current amplification of the pulses generated by the breaker points 11. The transistor has its base connected 'ice to one of the contact points in series with a small resistor 15. The transistor collector is connected to a ground connection in series with a second small resistor 16, while the emitter is connected to the positive terminal of the potential source it in series with the primary winding 17 of a charging transformer, the primary winding 2i) of a firing transformer 21, and a third resistor 19.

The circuit includes a charging path for charging a storage capacitor 22, this path including the secondary 23 of charging transformer 18, a diode rectifier 24, and the primary winding 25 of an output transformer 26. After the storage capacitor 22 is charged, it is discharged by a discharge circuit which includes a thyratron gaseous discharge device 27, the primary winding 25, and the storage capacitor 22. The control means for starting the discharge includes the firing electrode within the thyrat-ron 27 and a coupling circuit which includes a capacitor 28 and resistor 36 connected to a secondary Winding 31 on transformer 21.

The output circuit includes a secondary winding 32 on transformer as, a distributor 33, and a series of spark plugs 3 The distributor 33 has the usual stator electrodes, each connected respectively to one side of a spark plug and a rotating arm 35 whose rotary motion is controlled by shaft 13 coupled to cam 12.

During the operation of this circuit some excess voltage pulses may be generated which are not helpful to the efficient operation of the system. A diode rectifier 36 is connected between the negative electrode of battery it? and one side of a primary winding 17a. If for any reason during the operation of the system capacitor 22 is not discharged, the next voltage pulse through winding 17 will produce an excessive current pulse in both windings and this pulse is limited by diode 36 which sends the excess current through battery 13 in a direction which charges it. A second diode 37 is connected around one portion of secondary winding 31 and limits the negative portion of the pulse applied to the firing electrode in thyratron 27. The elimination of the negative portion of this pulse produces a more dependable firing action. A diode 38 is interposed in the input circuit between winding 26 and the emitter of transistor 14.

The operation of this device is as follows:

Transistor 14 is normally non-conductive when the contacts 11 are open and no current flows from the source of potential 1%) through windings 17 and 29, through the emitter-collector electrodes to the other side of the battery. When the points close, the transistor is made conductive and current flows through the above mentioned circuit causing the generation of a magnetic field in the core of transformers 18 and 21. The rise of current in this circuit is limited by resistor 16 and the resistances in windings 17 and 2% These pulses are shown graphically in FIG. 2 by pulses 40. When the contacts are opened, the current through windings 17 and 24 is cut oil abruptly and the magnetic flux in the cores of transformers 1S and 21 collapses and generates voltage pulses in secondary windings 23 and 31. The first time that the circuit is operated there is no charge on capacitor 22 and the rise of potential of the firing electrode in the thyratron produces no effect. However, the voltage generated in winding 23 passes through rectifier 24 and charges capacitor 22, this charging pulse 41 being shown in FIG. 2. The second time, and during all succeeding cycles the device is operated, the pulse generated by secondary winding 31 (pulse 42 in FIG. 2) sends a voltage through the

coupling circuit

30, 28 to the firing electrode of thyratron 27, maldng it conductive and discharging storage capacitor 22 through the tube 27 and primary Winding 25. This discharge current generally lasts for only 3 microseconds and occurs before the voltage generated by secondary winding 23 has a chance to charge capacitor 22. The duration of the disand the high voltage spark sent through the distributor to the spark plugs is shown in FIG. 2 as pulse 44.. The other voltage variations shown in FIG; 2 are self-evident. t will be noted that the voltage across the thyratron 27 swings negative during the discharge of the capacitor 22 due to the fact that the discharge circuit contains both to be interpreted in a limiting sense. The only limitatio'nsto be determined are from the scope of the appended claims. 7 V V i I claim: 7. a e

1. An ignition system for internal combustion engines 7 having 'a spark plug in each combustion chamber comprising: asource of direct current; a pair of; contacts controlled to open and close in synchronism with the movementsof pistons in the combustion cha'mbers; a

transistor having a base, an emitter, and a collector, with the base and collector connected across said contacts for control of the emitter-collector conductance; a charging transformer for generating an electrical pulse, said transformer including a primary winding connectedrin series between said source of current and the emitter; a

storage ca acitor for storin' an electrical char e forl V V V g 'nishe'd by said transformer when the current through the primary winding is reducedto zero; a rectifier diode I charge is shown by the short horizontal line 43 in FIG; 2

, inductance and capacity. This negative swing makes the anode of the thyratron negative for a short time interval @10 connected-in series between the storage capacitor and a secondary winding of the charging transformer; an out put circuit connected across the storage capacitor and the secondary of the charging transformer for delivering the charge stored by the capacitor to said spark plugs; a gaseous discharge device having an anode, a cold cathode, and a firing electrode with its anode connected to one side of said capacitor and its cathode connected to one side of the output circuit; and a firing circuit coupled to said firing electrode, said firing circuit including a firing transformer having a primary winding connected in series between the emitter and one side of the primary winding of the charging transformeigsaid firing transformer having a secondary winding coupled between the firing electrode and the cathode of said discharge device for firing the discharge device wh n said contacts are opened." a

2; An ignitionsystem as claimed in claim 1 wherein a portion of the secondary Winding of the firing transformer is bridged by a diode rectifier for preventing the firing electrode in the gaseous discharge device from going said output circuit includes an output transformer, a

distributor, and a plurality of sparkplugs.

' Jaeschke Aug. 4, 1959 3,032,685 Loornis May 1, 1962 3,047,728 Martin July 31, 1962 Quinn Aug. 14, 1962

Claims

1. AN IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES HAVING A SPARK PLUG IN EACH COMBUSTION CHAMBER COMPRISING: A SOURCE OF DIRECT CURRENT; A PAIR OF CONTACTS CONTROLLED TO OPEN AND CLOSE IN SYNCHRONISM WITH THE MOVEMENTS OF PISTONS IN THE COMBUSTION CHAMBERS; A TRANSISTOR HAVING A BASE, AN EMITTER, AND A COLLECTOR, WITH THE BASE AND COLLECTOR CONNECTED ACROSS SAID CONTACTS FOR CONTROL OF THE EMITTER-COLLECTOR CONDUCTANCE; A CHARGING TRANSFORMER FOR GENERATING AN ELECTRICAL PULSE, SAID TRANSFORMER INCLUDING A PRIMARY WINDING CONNECTED IN SERIES BETWEEN SAID SOURCE OF CURRENT AND THE EMITTER; A STORAGE CAPACITOR FOR STORING AN ELECTRICAL CHARGE FURNISHED BY SAID TRANSFORMER WHEN THE CURRENT THROUGH THE PRIMARY WINDING IS REDUCED TO ZERO; A RECTIFIER DIODE CONNECTED IN SERIES BETWEEN THE STORAGE CAPACITOR AND A SECONDARY WINDING OF THE CHARGING TRANSFORMER; AN OUTPUT CIRCUIT CONNECTED ACROSS THE STORAGE CAPACITOR AND THE SECONDARY OF THE CHARGING TRANSFORMER FOR DELIVERING THE CHARGE STORED BY THE CAPACITOR TO SAID SPARK PLUGS; A GASEOUS DISCHARGE DEVICE HAVING AN ANODE, A COLD CATHODE, AND A FIRING ELECTRODE WITH ITS ANODE CONNECTED TO ONE SIDE OF SAID CAPACITOR AND ITS CATHODE CONNECTED TO ONE SIDE OF THE OUTPUT CIRCUIT; AND A FIRING CIRCUIT COUPLED TO SAID FIRING ELECTRODE, SAID FIRING CIRCUIT INCLUDING A FIRING TRANSFORMER HAVING A PRIMARY WINDING CONNECTED IN SERIES BETWEEN THE EMITTER AND ONE SIDE OF THE PRIMARY WINDING OF THE CHARGING TRANSFORMER, SAID FIRING TRANSFORMER HAVING A SECONDARY WINDING COUPLED BETWEEN THE FIRING ELECTRODE AND THE CATHODE OF SAID DISCHARGE DEVICE FOR FIRING THE DISCHARGE DEVICE WHEN SAID CONTACTS ARE OPENED.