US1138569A - Ignition system. - Google Patents

Description

D. B. HUGHES.

IGNITION SYSTEM.

APPLICATION FILED 111 11.21. 1910. RENEWED sEPT.25. 1914.

1,138,569, Patented 1111 4, 1915.

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new 3. HUGHES, or CLEVELAND, OHIO, ASSIGNOR ho THE cI'rIzENs SAVINGS AN TRUST COMPANY, TRUSTEE, or CLEVELAND,

Y IGNITION SYSTEM.

Application filed April 27, 1910, Serial No. 557,889.

To all whom it may) concern:

Be it known that 1, Dow B. HUGHES, a

citizen of the United States, residing at terminals of the Spark plug connected to that secondary and thereby reduces the re- Cleveland, in the county of Cuyahoga and State of Ohio, have'inventeda certain new and useful Improvement. in Ignition Sys-' tems, of which the following is a full, clear, and exact description. r

This invention relates to ignition Systems for internal combustion engines and is de- I signed as an improvement over an ignition system disclosed in my pendin application, filed. 553,111. I r p The Specific objects of the present invention are to provide a system which is more satisfactory in operation than the one disclosed in my pending application referred to, and to simplify the construction of parts and the number and arrangement of elec-' tric conductors and connections, and to reduce the cost of construction and installation.

In accordance with the present invention, I employ in connection with a suitable source of current, such as a magneto having a low Voltage winding, suitable means for making and then breaking a short circuit about the winding and connect the wind' ing to a distributer, the stationary segments or contacts of which are each connected to one of the spark. plugs to a disrufitive discharge coil and to a condenser. denser which is connected to one of the dis" tributer segments. is connected to ground in series with the primary of the corresponding disruptive discharge coil and in shunt to the corresponding spark plug and the secondary of the coil, the secondary and Spark plug being in series.

The voltage of the generator is ordinarily insufficient to establish arcs across the terminals of the spark plugs, but with the arrangenient above described, by temporarily sort-circuiting the armature winding, and then opening the same, the condenser which is in circuit with the segment which happens to be connected to the armature winding through the movable member of the distributer is charged and discharged with great rapidity, setting up in the primary which is in series with that condenser, a high frequency current of high voltage but of extremely low. amperage. The high fre quency current induces a. high frequency Specification of Letters Patent.

April 2nd, I910, erial No..

ach conmarized as consisting in certain novel com- OHIO, A CORPORATION OF OHIO.

- 'Patented May 4, 1915. Renewed September 25, 1914. Serial No. 863,550."

-current in the corresponding -secondary, and

this induced high frequency current establishes an arc oflow heat value across'the sistance of the; air gap to an extent such that this are of low heat value is followed up by an arc of 'high heat value produced by magneto current, the voltage of the magneto to establish the are of high being sufficientheat value when the resistance of the air gap is reduced. The make and break device vertical position betweenthe "field poles, and

the short circuiticontin'ues while the armature turns through'a suitable are or fr'ac-' the magnetic field'and building' upthe volt age so that when the Short circuit is broken" and the high frequency current-is induced in one of the spark plug circuits, the mag'- neto voltage will be suflicient to establish"- the arc of high heat value. This are of high heat value having been established be:

tween the electrodes, it continues for a con-.- siderable period and, in fact, it continues until after the armature has. been moved through a considerable arc-and has passed beyond the position of highest Volta e.

The invention may be further brie y sumbinations and arrangements of parts which will be described in thespecification and set forth in the appended claims.

Reference is had to the. accompanying sheet of drawings wherein Figure lis' a diagrammatic view of my improvedignition system for a four cylinder engine, parts on the magneto armature shaft being projected at right angles so as. to show more clearly the operation and electric con- 105 nections; Fig. 2 is a diagrammatic view of a portion of the fields and armature of the magneto and showing by dotted lines the' approximate positions of-the armature when the armature winding is short circuited, and

tion of a-revolution and is sweeping intoshaft sections Hand 12 when the short circuit is broken; Fig. 3 is a sine voltage curve showing graphically the approximate comparative voltages when the winding is short circuited-and opened.

Referring now to the figures of the drawing, and firstto Fig. 1, 10 represents the magneto armature. which is su ported on and is provided with a single'low voltage winding 13, one end of which is grounded at 141, and the other end of which is connected to a collector ring 15 which is supported on shaft .section 12, and is engaged by a brush 16.

At the opposite side of the generator from the ring 15 is a make and break device for short-circuiting and opening the short circuit of the armature winding, this make and break device including a cam 17, a lever 18. adapted tov be shifted by the cam, and a contact member 19 adapted to be engaged by a corresponding contact member 20 on the lever, this contact member 19 being insulated from the frame work of the machine and being connectedby a conductor 21 to the brush 16. .The cam is constructed in a manner such that at each half revolution thereof, the contact members 19 and 20 are brought into engagement, and therefore, as the cam and lever 18 are both grounded, the armature winding will be temporarily shortcircuited upon itself at each half revolution. The cam and lever are shown Fig. 1, for the sake of clearness, as grounded by conductors, but in reality, by being mounted on the .grounded shaft section 11, and the lever 18 Wlll be grounded by being pivotedupon a portion of the magnetoframe.

At 22 is shown a distributer or timing device which, for a four-cycle four cylinder enginewill' be driven at one half magneto speed, and which is provided with a mova le distributer arm 22, and stationary con facts or segments 22, the former being per manently connected by a conductor 23 to the brush 16 which engages the collector ring 16, to which oneend of the armature winding is connected. The distributerarm is therefore at "all times electrically connected to the armature winding. Each ofthese segments 22? is connected through the primary 24 of a disru tive discharge coil. .24 and through a con enser 25 ,to ground, and is also connected through the'secondary 24 'of the disruptive discharge coil vto oneof the spark plugs 26, one terminalof which is, of

'course," grounded. The primary of the coil and condenser are therefore in shunt to the secondary of the coil and thespark plug. The condensers 25 have small-capacity, as compared with the vcondensers ordinarily employed in ignition systems, and in fact, I find that a condenser formed of substanr tially twenty square inchesof tin-foil arranged instrips, and separated by mica, pro:

the cam is grounded duces very good results, whereas the condenser ordinarily employed in an ignition system containsjhundreds of square inches of tin-foil. Also the disruptive discharge coils have very ,low reactance, this condisegments of the distributer and consequently the different spark plugs are successively connected to the armature Winding, and by driving the distributer at one half the speed of the magneto and by providing a make and break device which short circuits the armature winding and then opens the same twice at each revolution of the magneto, as the distributer arm passes onto one of the segments, the armature is short circuited and remains short-circuited for a fraction of a revolution of the armature, and is then opened. By opening the short-circuit, the condenser 25, which is connected to that segment, is charged and discharged, causing a high frequency current to be set up in the primary 2& to which the condenser is connected, and this high frequency current which is of high voltage but almost'negligible amperage, induces a high frequency current in the corresponding secondary 2 1". This induced high frequency current being of very high voltage, although of low amperage, causes an arc of low heat value to be established across the corresponding spark lug. This are is of insufficient heat value to ignite the explosive mixture in the cylinder of an engine, but it reduces the resistance of the air gap of the spark plug to an extent such that the magneto current at the generated voltage will establish a flaming arc of, high heat value at the spark plug, the current passing directly from the distributer arm to the segment previously referred to, and into the plug through the secondary of the induction coil. The condenser or high frequency circuit does not includethe armature winding because of the make and. break device which, as before stated, is in shunt to. or. short circuits the armature winding. On the opening of the make, and break device the latter serves as 'a spark gap device across which the condenser is disruptively discharged. As the distributer arm passes to the next segment,

' the armature winding is again short circuit-' high frequency current which induces in the denser for each spark plug, each of the stationary members of the distributer being connected to ground through the primary of a disruptive discharge coil and condenser, and each being connected to a spark plug through the secondary of the disruptive discharge coil.

5. In an ignition system, a magneto having an armature winding, one end of which through a condenser and a primary of a.

disruptive discharge coil, and being connected to ground. through the secondary of the coil and through a spark plug, the

condenser and primary being 1n serles relation and being in shunt to the secondary and the spark plug which are in series relation,

and means for making and breaking a short circult'about the armature winding.

6. In an ignition system, a generator, having a winding with means fortemporarily and periodically short-circuiting the same, a plurality of spark plugs, a distributer havlng its movable member connected to the "winding and having stationary contacts connec'ted to the difierent spark plugs, a'condenser connected to each of the distributer contacts, a plurality of disruptive discharge rent, a plurality of spark plugs,

coils, each having a primary connected to the condenser and a'secondary connected to a spark plug.

' 7 Inan ignition system, a source of cura disruptive discharge coil and a condenser for each spark plug, each condenser and a primary of one coil being in series relationship, and a spark plug and the secondary of the same coil being in series relationship, and means including a distributerfor establishing connection between the source of current and the different condensers, and also between the source of current andthe difierent spark plugs.

I 8;" In an ignition system, a source of current, a imake and break device associated therewith,'a plurality of spark plugs, a distributer having its movable member connected to the source of current and having stationary contacts connected to the different A 65 spark plugs, a condenser connected to each of the distributer contacts, a plurality of disruptive discharge coils, each having a primary connected to a condenser, and a secondary connected to a spark plug. In testimony whereof, I hereunto afilx my signature in the presence of two witnesses.

DOW HUGHES.

Witnesses:

H. R. SULLIVAN, A. F. Kwrs.

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