US2552989A - Electronic ignition system - Google Patents

Description

M y 1951 w...c;. MAYER 8 ELECTRONIC IGNITION SYSTEM Filed Jan. 30, 1948 anoentoz William GMayer. atter/nu v I.

Patented May 15, 1951 UNITED STATES eATENr OFFICE 2 Claims.

This invention relates to an electronic ignition system for internal combustion engines.

My present invention provides a generally improved electronic ignition system which, among other features, embodies automatic electrical means for timing the ignition or advancing the spark, avoids misfiring, eliminates the usual troublesome contact points, provides more exact timing and more efficient ignition and has other important advantages, hereinafter set forth or appreciated by those skilled in the art, and furthermore provides a new and more efficient method for firing the explosive mixture in the cylinders of an internal combustion engine. Additionally, the invention may be readily applied to present day engine models.

The mentioned method for firing the explosive mixture in the cylinders of an internal combustion engine, which is not dependent on the apparatus shown for carrying out the method, comprises the transformation of electrical energy, by any suitable means, into the form of a pulse, and preferably a single pulse, which may be a square pulse, and then applying the pulse to effect a spark in the explosive mixture, whereby to secure more efficient ignition and consequently,

more powerful engine strokes.

To outline the apparatus to be described below as illustrating one embodiment of my invention, it may be said that I employ a switch, shown as an electric switch in the form of a tube adapted to be periodically triggered or fired, means for so actuating the switch, which said means may be of any suitable type, such for-example as an A. C. generator operated in synchronism with, or by, the engine, said generator being desirably of the type which, in my ignition system, provides automatic control of the ignition timing, 1. e., automatic spark advance. Additionally, I employ means adapted to be periodically charged and discharged, the charging. being to a constant voltage regardless of the variable engine speed, and independent of the voltage of the mentioned generator or other source used to actuate the switch. The ignition voltage is thereby advantageously maintained constant at all engine speeds to secure the several advantages conless of engine speed, and discharges when the switch is closed. The discharge pulses are preferably transmitted to the distributor and from there communicated to the spark plugs to fire the same. In combination with the mentioned components, I may use a pulse transformer, to duplicate, at a higher voltage, the discharge pulses mentioned, which pass, after their formation, through the primary of the pulse transformer. Said transformer is desirably a low turns-ratio transformer so that, regardless of certain adverse conditions in the distributor, spark plugs and cables, as to be mentioned, the substantially constant voltage of the pulse-forming means may be transmitted to the spark plugs, whereby, among other advantages, misfiring is avoided. It may be here added that a pulse is defined as a sudden change of voltage or current of short duration; which duration is usually measured in microseconds. By using a pulse as aforesaid, I concentrate all the available energy in one intense burst of power, to secure a more effective spark. The spark resulting from the pulse is more reliable in exploding the charge within a cylinder, and also effects a quicker and therefore a more powerful explosion, which means greater engine power and fuel eficiency.

The accompanying drawing illustrates one embodiment of my invention.

Referring to the drawing for a more detailed description, the numeral 3 indicates a known type. of distributor, modified as presently to be explained. The distributor comprises a housing 4',

conductor terminal 5 (one shown) of conductors sequent thereupon. The means to be charged 6 which lead to the several spark plugs (not shown). The distributor shaft 7 rotates a known and used type of distributor arm 8, which extends to within sparking distance of the conductor ter'- minals 5. In accordance with my invention, I provide means for driving a generator I from the drive shaft 1 of the distributor. Thelatter, as stated, is of known design, modified to provide means for driving the generator. The driving means shown comprises a bevel gear l2 fixedly mounted on the distributor shaft 7. Meshing with the gear I2 is a bevel gear Hi mounted on a horizontal shaft l5 which'rotates in a bearing I6 set in the wall of the distributor housing. The gears l2 and I4 have the required ratio.

The generator It may be an A. C. generator, so that its voltage maybe stepped-up by means of a transformer. The generator is shown as comprising a semi-circular permanent magnet I8 mounted .on the shaft 15, tobe rotated thereby to provide a rotating field. Said magnet is designated in the drawing by the numeral 52, and its output impedance is only about 1 5' as much as that of the currently used transformers. This transformer is preferably a pulse transformer and its use as part of the system is a feature of my invention. The importance and value of this feature will be appreciated below. Said pulse transformer comprises a primary 53 having one terminal connected to the pulse forming network 50 and the other terminal grounded at 55. The secondary 5B of this transformer has one terminal grounded and the other connected to the mentioned distributor arm 8 through a cable 58. A load resistor 60 is connected across the secondary and has such value that it matches the characteristic impedance of the pulse-forming network.

A still further feature of my invention provides a single pulse for firing a plug, instead of producing the usual series of damped oscillations given by ignition coils. Further, the comparatively slow rising waves of such oscillations do not immediately develop a firing voltage at the beginning of a cycle, and therefore result, not only in wasted power, but also in a time lag which retards the spark timing as the engine is operated at higher speeds. With my invention, however, the use of the pulse-forming network avoids such a condition, and all the developed power is put into a single pulse, which effects more eiiicient firing of the spark plugs. Any one of the several types of pulse-forming networks may be employed, the one shown being what is known as type E, and is shown as comprising three sections, each consisting of an inductance and capacitance. The values of the latter control the pulse width, as known, and that width may be varied in accordance with the type of fuel used, the compression of the engine, etc. Such a pulse network may be designed, as known, to produce a pulse having the desired steepness of wave front, and preferably is made to produce a wave which is represented graphically by a substantially perpendicular wave front, such as a square wave, whereby the firing voltage is practically instantaneously developed. This is an advantageous distinction and advance over the use of an ignition coil, with which, at high engine speeds, the primary current does not have time to develop to its maximum, due to the high inductance, resulting in lower secondary voltages at the higher speeds, so that the firing voltage is different for different engine speeds, with a consequent undesirable non-uniformity or irregularity of ignition, as contrasted with the uniformity provided by the presently disclosed system.

It will be appreciated from the foregoing that I provide a new and more efiicient method for firing the explosive mixture in an internal combustion engine, comprising the formation of what is technically called a pulse, and preferably a single pulse, which may be square or substantially so, and then effecting a spark Within the mixture by means of the pulse,

The mentioned pulse-forming means and pulse transformer are valuable features of my invention, for the reasons stated, and while known and used in the art of object detection, have long been overlooked as having significant advantages in the present art.

In operation, the pulse-forming network is charged through the primary of the pulse transformer to ground, the thyratron being open. When the thyratron fires, the pulse-forming network, which is connected to the anode of the thyratron, discharges through the thyratron to ground, the current return being through the primary of the pulse transformer. The pulses formed in the primary of the transformer are duplicated in form, at a higher potential, in the secondary thereof, and are transmitted to the spark plugs to fire the same with the efliciency and advantages aforesaid.

I claim:

1. In an ignition system of an internal combustion engine, means for periodically forming a single substantially square pulse only, means for periodically charging said pulse-forming means, a pulse transformer having a primary and a secondary, a distributor and means adapted to be synchronized with the engine to periodically allow said pulse forming means to discharge through said primary of the pulse-forming transformer, the secondary of the transformer being operatively connected to said distributor.

2. In an ignition system of an internal combustion engine, the combination of a switch tube, a distributor driven by the engine and having a shaft, an A. C. generator driven by said shaft and adapted to open and close said switch tube, a full wave rectifier adapted to rectify the voltage of said generator, said generator being characterized by an increase of voltage with speed, to automatically advance the ignition, a pulse transformer, means connected to said transformer and adapted to be periodically charged and discharged, said means being adapted to discharge periodically, through said transformer, to said distributor, a single substantially square pulse only, when said switch tube is closed, said generator comprising a field magnet and an armature core, one of which is rotatable and angularly adjustable to facilitate the proper timing of the ignition system, and a condenser-resistance combination for regulating the voltage of said generator.

WILLIAM G. MAYER.

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

UNITED STATES PATENTS Number Name Date 2,353,527 Touceda July 11, 1944 2,400,456 Haine et al May 14, 1946 2,446,671 Short et al. Aug. 10, 1948 2,463,123 Short et a1 Mar. 1, 1949 2,472,671 McNulty June '7, 1949 2,474,550 Short et al June 28, 1949 2,490,960 Hanchett Dec. 13, 1949

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