US3072823A - Internal combustion engine ignition system - Google Patents

Description

Jan. 8, 1963 T. E. KIRK INTERNAL COMBUSTION ENGINE IGNITION SYSTEM INVENTOR.

THOMAS E. KIRK a RI MM HIS ATTORNEY Filed June 23, 1960 3,ti72,823 TNTERNAL (IOMBUSTHON ENGINE TGNHTIGN SYSTEM Thomas E. Kirk, Anderson, Ind, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Fitted dune 23, 196i Ser. No. 38,204 12 Claims. (Cl. 315-205) This invention relates to an ignition system for an internal combustion engine and more particularly to an ignition system wherein a semi-conductor such as a transistor is used to control current flow through the primary winding of an ignition coil.

One of the objects of this invention is to provide an ignition system for controlling the firing of a spark plug of an internal combustion engine that includes a pair of semi-conductors that are connected to be alternately conductive and wherein one of the semi-conductors is connected to control the current fiow through the primary winding of an ignition coil.

Another object of this invention is to provide an internal combustion ignition system including a pair of interconnected transistors, one of which controls current flow through the primary winding of an ignition coil and the other of which has its conductance controlled by a device which operates in timed relationship to rotation of the crank shaft of the engine.

A further object of this invention is to provide an ignition system for an internal combustion engine that includes a first transistor that controls current flow through the primary winding of an ignition coil and a second transistor connected with the first transistor, the second transistor being normally biased to a state of conduction and being periodically rendered non-conductive by a voltage pulse generating device that operates in synchronism with the engine.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE 1 is a schematic illustration of an ignition system made in accordance with this invention.

FIGURE 2 illustrates a modified ignition system made in accordance with this invention.

Referring now to FIGURE 1 the reference numeral designates a source of direct current power which in this case is a storage battery. The storage battery in the motor vehicle is connected to be charged by a generator (not shown) and when the generator is in operation the generator does provide power for the ignition system. It is seen that one side of the battery 10 is connected directly to ground whereas the opposite side thereof is connected with an ignition switch 12.

The ignition system includes an ignition coil generally designated by reference numeral 14 having a primary winding 16 and a secondary winding 18. One side of the primary winding 16 is connected directly to ground as well as one side of the secondary winding 18. The opposite side of secondary winding 18 is connected with a rotor contact 20 of a distributor which cooperates with the contacts 22 carried by the distributor cap 24. The contacts 22 are connected by suitable lead Wires with spark plugs and, as is well known to those skilled in the art, as the rotor 20 rotates, spark impulses are supplied to the spark plugs of the engine. In the schematic illustration only one spark plug 26 is shown, it being understood however, that each distributor cap contact is connected with a spark plug. It will, of course, be appreciated that the rotor 20 is driven in synchronism with the en- 3,072,823 Patented Jan. 8, 1963 gine in a manner well known to those skilled in the art.

One side of the primary winding 16 of ignition coil 14 is connected with the collector electrode 28 of a pnp transistor generally designated by reference numeral 30. This transistor has a base electrode 32 and an emitter electrode 34. The emitter electrode 34 is connected with the lead wire 36 which, in turn, is connected to one side of ignition switch 12. The base electrode 32 of transistor 30 is connected with a junction 38 and it is seen that resistor 40 is connected between lead wires 36 and the base electrode of transistor 36 and, thus, is connected across the emitter and base electrodes of transistor 30.

A second transistor generally designated by reference numeral 42 is provided which has an emitter electrode 44, a base electrode 46, and a collector electrode 48. This transistor is also a pnp transistor although it will be apparent to those skilled in the art that npn transistors could be used for transistors 30 or 42. The emitter electrode 44 of transistor 42 is connected directly with lead wire 36 whereas the collector electrode 48 is connected with junction 38. The junction 38 is connected to ground through a resistor 50.

The device for causing a timed firing of the spark plugs in the ignition system of this invention includes a voltage pulse generating device having a pickup coil 52 and a permanent magnet rotor assembly 54. The permanent magnet assembly 54 is driven by a shaft 56. The shaft 56 is driven in synchronism with the rotor contact 20 and both of these elements are driven by the engine. The rotor assembly 54 will have six permanent magnets when used with a six cylinder engine so that as the permanent magnet assembly 54 rotates with respect to pick up coil 52 six pulses of voltage are generated in the pickup coil for every revolution of the shaft 56. It is pointed out that the number of permanent magnets included in the rotor assembly 54 forms no part of this invention and as many magnets may be used as are required depending upon the number of cylinders of the engine.

In the operation of the ignition system of FIGURE 1, when the ignition switch 12 is closed a circuit is completed to one side of the storage battery 10. It will be observed that the emitter electrode 44 of transistor 42 is at the same potential as one side of the battery it and further that the base electrode 46 of transistor 42 is substantially at the same potential since it is connected with lead wire 36 through the pickup coil 52. It, thus, is seen that with the ignition switch 12 closed the emitter and base electrodes of transistor 42 are at substantially the same potential so that the transistor 42 is non-conductive between emitter and collector.

On the other hand, when the ignition switch 12 is closed, the transistor 30 is biased to be fully conductive between emitter and collector so that upon initial closing of the ignition switch current will flow through the primary winding 16 of the ignition coil. If the engine is now cranked so that the shaft 56 and rotor contact 20 are rotated, pulses of voltage will be generated in the pickup coil 52 as the permanent magnet assembly rotates with respect thereto. These pulses of voltage are of such a polarity as to cause the emitter electrode 44 of transistor 42 to become positive with respect to the base electrode 46 and thus cause the transistor 42 to become conductive between emitter and collector. With transistor secondary winding 18 which is applied to the spark plugs 26 through the rotor contact 20. The same operation occurs once the engine has been started since the rotor assembly 54 causes pulses of voltage to be generated in the pickup coil 52 and thus causes transistor 42 to be periodically turned on with a consequent periodic shutting E of transistor 30.

It will be apparent from the foregoing that the transistor 42 is normally non-conductive except when a pulse of voltage is induced in the pickup coil 52. It will also be apparent that the conduction of transistor 30 is opposite to the state of conduction of transistor 42, or in other words, when transistor 42 is fully conducting, transistor 30 is fully non-conductive and vice versa.

Referring now more particularly to FIGURE 2, a modified ignition system made in accordance with this invention is illustrated. In FIGURE 2 the same reference numerals have been used as Were used in FIGURE 1 to identify the same circuit element in each figure. The FIGURE 2 arrangement illustrates an ignition system that is operable without the use of breaker points, a distributor or a distributor cap.

In the FIGURE 2 arrangement a pair of ignition coils are employed, one of which is designated by reference numeral 60 and the other of which is designated by reference numeral 62. The ignition coil 60 has a primary winding 64 and a secondary winding 66. In a like manner, the ignition coil 62 has a primary winding 68 and a secondary winding 70. It is seen that the secondary winding 66 is connected directly with spark plugs 71 and 72 whereas the secondary winding 70 is connected directly with spark plugs 76 and 78.

In the embodiment of FIGURE 2 a magnetic rotor assembly 80 is provided having four permanent magnets and this rotor assembly is rotatably driven by a shaft 82. It will, of course, be appreciated that the magnetic rotor 30 might be affixed directly to the fly wheel of an engine, it being understood that any arrangement may be employed wherein a magnetic rotor assembly is rotated in timed relationship with the engine.

The rotor assembly 80, as it rotates, induces voltages in pickup coils 84, 86, 88 and 90. The pickup coils 84 and 88 are used in starting the engine to provide a somewhat retarded spark. The pickup coils 86 and 90 are, on the other hand, used when the engine is running and have an advanced spark as compared to the situation where the coils 84 and 88 are used. This being true, it is necessary, of course, that the coils 84 and 83 be circumferentially spaced and, in a like manner, it is necessary that coils 38 and 90 be circumferentially spaced so that a pulse of voltage will be induced, for example, in coil 86 before one is induced in coil 84 as the rotor member 80 rotates.

In the system of FIGURE 2 either the coils 84 and 88 are connected into the circuit or the coils 86 and 90. This is accomplished by switching means which includes movable contactors 92 and 94 which are ganged together and which cooperate respectively with contacts 96 and 98 and with contacts 100 and 102. It is seen that the shiftable contactors 92 and 94 are connected with the base electrodes of the transistors 42.

It can be seen from the FIGURE 2 embodiment that the ignition coils 60 and 62 are fed through two different channels or circuits which are identical with a part of the circuit illustrated in FIGURE 1. In other words, a pair of transistors 30 and 42 control the current flow to the primary winding 64 of ignition coil 60 while still another pair of transistors 30 and 42 control the current flow to the primary winding 68 of ignition coil 62. It will be appreciated that when current flow is interrupted to either primary winding 64 or 68, a spark impulse is applied to spark plugs 71 and 72 or the spark plugs 76 and 7 8.

The pickup coils 84, 86, 88 and 90 are so spaced that the spark plugs 71 and 72 will fire when, for example,

at the point of time where the piston within the cylinder that is fired by spark plug 71 is in the right point in its compression stroke. It will, of course, be appreciated that simultaneously with the firing of spark plug 71 the spark plug 72 is likewise fired, but at that time, the piston in the cylinder which is fired by spark plug 72 is in such a portion of its cycle that this firing has no harmful effect. The same is true of the spark plugs 76 and 78 and it is, thus, seen that the four cylinder engine will have properly timed sparking without the use of a distributor rotor, for example, like that illustrated by reference numeral 20 in FIGURE 1.

As pointed out hereinbefore, when the engine is to be started the contactor 92 is shifted into engagement with fixed contact 96 and the contactor 94 is shifted into engagement with fixed contact 100. This brings the pickup coils 84 and 88 into the circuit so that the spark is somewhat retarded during cranking or starting of the engine. On the other hand, once the engine is operating the contactors 92 and 94 may be shifted over into engagement with fixed contacts 98 and 102 to bring the pickup coils 86 and into operation whereby a slightly advanced spark from that previously had is achieved.

In summary, it can be seen that the ignition system of FIGURE 2 provides properly timed spark impulses to a four cylinder engine for firing the spark plugs of this engine wthout the use of breaker contacts or a distributor rotor and distributor cap. In addition, this control is achieved through the use of two circuit networks of transistors as explained above.

While the embodiments of the present invention as herein disclosed, constitute preferred forms, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. An ignition system for controlling the firing of a spark plug in an internal combustion engine comprising, a source of direct current power, an ignition coil having a primary winding and a secondary winding, means connecting said secondary winding with said spark plug. first and second semiconductors, means interconnecting said semiconductors and said power source whereby said first semiconductor is substantially fully conductive when the second semiconductor is substantially fully non-conductive, means connecting said first semiconductor between said power source and the primary winding of said ignition coil, and means for controlling the conduction of said second semi-conductor in timed relationship with operation of said engine.

2. An ignition system for controlling the firing of a spark plug in an internal combustion engine comprising, a source of direct current power, an ignition coil having a primary winding and a secondary winding, means connecting said secondary winding with said spark plug, first and second transistors. means interconnecting said transistors and said power source whereby one of said tran sistors is rendered substantially fully conductive when the other of said transistors is substantially full non-conductive and vice-versa, means connecting one of said transistors between said power source and the primary winding of said ignition coil whereby the current flow through said primary winding is controlled as a function of conductance of said one transistor, and means for controlling the conduction of said other transistor in timed relationship to the operation of said engine.

3. An ignition system for controlling the firing of a spark plug in an internal combustion engine comprising, an ignition coil having a primary winding and a secondary winding, 21 direct current power source, means connecting the secondary winding of said ignition coil with said spark plug, first and second transistors, means interconnecting said transistors and said power source whereby one of said transistors is substantially fully conductive when the other of said transistors is substantially fully non-conductive and vice-versa, means connecting one of said transistors between said power source and the primary winding of said ignition coil, a pulse generating device operative to supply pulses of voltage in timed relationship with operation of said engine, and means for applying said pulses of voltage to the base circuit of said other transistor.

4. An ignition system for controlling the firing of a spark plug of an internal combustion engine comprising, a source of direct current power, an ignition coil having a primary winding and a secondary winding, means connecting said secondary winding with said spark plug,- semiconductor means connected between said primary Winding and said power source for controlling the current flow through said primary winding as a function of conductance of said semiconductor means, a pulse generating device including a pair of pickup coils and a magnetic device rotatable with said engine, and means for alternately connecting said pickup coils with said semiconductor means.

5. An electrical ignition system comprising, a source of direct current power, first and second ignition coils each having a primary winding and a secondary winding, first and second spark plugs, means directly connecting the secondary windings of said ignition coils respectively with said spark plugs, first semiconductor means connected with the primary winding of one of said ignition coils, second semiconductor means connected with the primary winding of the other ignition coil, and pulse generating means operated in synchronism with said engine for controlling the conduction of said semiconductor means.

6. An electrical ignition system comprising, a source of direct current power, first and second ignition coils each having a primary winding and a secondary winding, a first plurality of spark plugs directly connected with the secondary winding of said first ignition coil, a second plurality of spark plugs directly connected with the secondary winding of said second ignition coil, first and second semiconductor means connected respectively between the power source and the primary windings of said ignition coils, and pulse generating means operated in synchronism with said engine for controlling the conduction of said semiconductor means.

7. An ignition system for controlling the firing of spark plugs in an internal combustion engine comprising, a first ignition coil having a primary winding and a secondary winding, a second ignition coil having a primary winding and a secondary winding, spark plugs directly connected with the secondary windings of said ignition coils, a source of direct current power, means for controlling the current flow between said source of power and the primary winding of said ignition coiis including first and second semiconductor means, pulse generating means including a member rotatable with said engine and first and second pairs of pickup coils, and means alternately connecting one of each of said pairs of pickup coils in controlling relationship with one of said semiconductor means.

8. An ignition system for controlling the firing of a spark plug of an internal combustion engine comprismg, a source of unidirectional voltage, an ignition coil having a primary winding and a secondary winding, means connecting said secondary winding with said spark plug, first and second transistors each having emitter, base and collector electrodes, an energizing circuit for the primary winding of said ignition coil including in a series connection, said voltage source, said primary winding and the emitter-collector circuit of said first transistor, means connecting the emitter-collector circuit of said second transistor across said voltage source, a biasing circuit for normally maintaining said first transistor conductive in its emitter-collector circuit, said biasing circuit including in a series connection, said voltage source and the emitter-base circuit of said first transistor, means connecting the base electrode of said first transistor with the collector electrode of said second transistor whereby said first transistor has its conductivity sub- 10. The system according to claim 8 wherein the tim-' ing means includes a coil winding connected across the emitter-base circuit of said second transistor which is capable of having voltage pulses induced therein in timed relationship with operation of said engine.

11. An ignition system for controlling the firing of a spark plug in an internal combustion engine comprising, a source of unidirectional voltage, an ignition coil having a primary winding and a secondary winding, means connecting said secondary winding with said spark plug, first and second transistors each having emitter, base and collector electrodes, an energizing circuit for the primary winding of said ignition coil including in a series connection said source of voltage, said primary winding and the emitter-collector circuit of said first transistor, means connecting the collector electrode of said second transistor and the base electrode of said first transistor together and to one side of said source of voltage, means connecting the emitter electrode of said second transistor to an opposite side of said voltage source, a coil winding in which voltage pulses are induced in timed relationship with operation of said engine, and means connecting said coil winding across the emitter and base electrodes of said second transistor, said coil winding being operative to place the emitter and base electrodes of said second transistor at substantially equal potentials when no voltage is induced in said coil winding and operative to cause a difference in potential between said emiter and base electrodes when a voltage is induced in said coil winding.

12. An ignition system for controlling the firing of a spark plug in an internal combustion engine comprising, a source of unidirectional voltage, an ignition coil having a primary winding and a secondary winding, means connecting said secondary winding with said spark plug, first and second transistors each having emitter, base and collector electrodes, an energizing circuit for said primary winding including in a series connection, said source of voltage, said primary winding and the emittercollector circuit of said first transistor, timing means including a coil winding in which pulses of voltage are induced in timed relationship with operation of said engine, means connecting one side of said coil winding and the emitter electrode of said second transistor with one side of said source of voltage, means connecting the opposite side of said coil winding with the base electrode of said second transistor, means connecting the collector electrode of said second transistor with the side of said source of voltage opposite to that which is connected with the emitter electrode of said second transistor, and a circuit connecting the collector electrode of said second transistor with the base electrode of said first transistor.

References Cited in the file of this patent UNITED STATES PATENTS 1,272,056 Kettering July 9, 1918 1,676,503 Rippingille July 10, 1928 2,953,719 Guiot Sept. 20, 1960 3,034,018 Rosenberg May 8, 1962 FOREIGN PATENTS 1,137,949 France --.r-,- Jan. 21, 19 57

Claims (1)

1. AN IGNITION SYSTEM FOR CONTROLLING THE FIRING OF A SPARK PLUG IN AN INTERNAL COMBUSTION ENGINE COMPRISING, A SOURCE OF DIRECT CURRENT POWER, AN IGNITION COIL HAVING A PRIMARY WINDING AND A SECONDARY WINDING, MEANS CONNECTING SAID SECONDARY WINDING WITH SAID SPARK PLUG, FIRST AND SECOND SEMICONDUCTORS, MEANS INTERCONNECTING SAID SEMICONDUCTORS AND SAID POWER SOURCE WHEREBY SAID FIRST SEMICONDUCTOR IS SUBSTANTIALLY FULLY CONDUCTIVE WHEN THE SECOND SEMICONDUCTOR IS SUBSTANTIALLY FULLY NON-CONDUCTIVE, MEANS CONNECTING SAID FIRST SEMICONDUCTOR BETWEEN

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