US2392171A - Ignition unit - Google Patents

Description

Jan. l, 1946. M. o. MARSH IGNITION UNIT Filed Jan. 1, 194e Inventor: Myfle O. Marsh, by WM His Attorney.

Patented Jan. 1, 1946 IGNITION UNIT Myrle 0. Marsh, Fort Wayne,

General Electric Company,

New York Ind., assigner to a corporation oi' Appllcaton January 1, 1943, Serial No. 470,980

12 Claims.

My invention relates to ignition units and particularly to a high frequency electric spark discharge unit such as may be used in connection with internal combustion engines.

An object of my invention is to provide an im proved ignition unit oi the high frequency type.

Another object of my invention is to provide an improved ignition unit provided with an oscillation discharge circuit for supplying a high frequency current to discharge electrodes thereof.

Further objects and advantages of my invention will become apparent and my invention will be better understood from the following description referring to the accompanying drawing, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In the drawing, Fig. l is a sectional view through an ignition unit embodying my invention wherein the unit includes an improved form of oscillation transformer and discharge electrodes; Fig. 2 is a sectional view showing a modification of the arrangement in Fig. 1 wherein the unit includes the features of Fig. 1 and in addition a compact oscillation circuit formed by a capacitor, a quenched spark gap device, and an oscillation transformer connected to discharge electrodes; and Fig` 3 is a further modication of the arrangement shown in Fig. 2 wherein a single high dielectric constant insulating material is used to insulate the primary and secondary windings from each other and from the barrel of the unit.

Referring to the drawing, I have shown in Fig. 1 an embodiment of my invention wherein an ignition unit is provided with a barrel or shell iii which is adapted to be secured in a threaded opening in an engine cylinder bloei: by engagement therewith of a lower threaded portion ii of the barrel. A source of high frequency electric current is supplied to the unit by a distributor lead conductor i2 arranged within a radio shielding armor i3 and insulated therefrom by an insulating covering il. The conductor i2 is secured to the ignition unitl in an insulating terminal plug element i5 in which a terminal screw Iii is threaded into good electrical contact with the end of the distributor conductor i2. This terminal plug I5 is held in position in the upper end of the barrel i by securing a flange il of the plug i between the upper end of the casing i0 and a flange IB formed on the end of the shielding armor i3. This assembly is retained in assembled relationship by a nut I9 which threadedly engages the upper end 29 of the barrel ill and is provided with an inturned flange 2| which engages the outer surface of the ilange I8 and biases the flange IB toward the end of the barrel IB. The terminal screw i8 forms an electrical contact with spring lingers 22 of a terminal cap 23 provided with a threaded retaining end portion 2| molded within a core member 25 of high dielectric constent and fusing point insulating material, such as porcelain or other suitable material. The high frequency current supplied to the ignition unit by the distributor conductor i2 is adapted to be supplied at a relatively low voltage to a primary winding 26 of an oscillation transformer which is connected at one end 21 to the terminal 24 and at the other end 23 thereof to the barrel Ill through a sleeve 29 of electrically conductive material. The oscillation transformer is provided with a secondary winding 30 which is arranged about the upper portion of the insulating member 25 which forms a SuDDOrting core for the secondary winding 39 extending substantially the full length thereof and is insulated from the transformer primary winding 26 by an insulating sleeve eiement 3i. One terminal 32 of the transformer secondary winding 30 is connected to the terminal element 24 and to the adjacent end 21 ci the transformer primary winding, and the other end 33 of the transformer secondary winding extends through an opening 34 in the insulating core 25 into a central opening 35 formed in the lower end of the core element 25. The end 33 of the transformer secondary winding is electrically connected to a central spark discharge electrode 36 which is mounted in the opening 35 in the insulating core element 25 and is held in position therein by a pin 3l which extends through the electrode 33 and. into pockets formed in the insulating core member 25. An insulating plug 38 is arranged over the end of the pin 3l in the core member to prevent electrical discharges between the pin 3l and the sheii Iii. The insulating core member l25 is secured in position within the shell iii by a shoulder 39 formed thereon arranged in engagement with a gasket 4D pressed between the shoulder 39 and a flange AI formed on the barrel l0. Provision is made for the desired expansion due to the variations in temperature of the ignition unit by the arrangement of the sleeve 29 about the shoulder portion 39 of the insulating core member 25 and by the gasket 4i which varies in dimension under the different heat conditions to provide for an'y relative difference in expansion and contraction between the barrel IIJ and the core member 25. The shoulder 39 of the core member 25 is held in the above-mentioned position by a ring 42 arranged in the lower end of the barrel i in engagement with the lower edge of the shoulder portion 39 between this lower edge and a set of discharge electrodes 43. A ange or lip 44 formed on the lower end of the barrel I0 is turned in to hold these elements in assembled relationship. This arrangement provides a spark discharge gap between the central electrode 35 and the electrodes 43 which is supplied with a high frequency current at a relatively high voltage by the transformer secondary winding and minimizes the possibility of electrical losses and discharges between the source of high-voltage high-frequency current and the spark discharge electrodes.

In Fig. 2, I have shown a modification of the arrangement shown in Fig. 1 wherein the ignition unit includes a self-contained oscillatory circuit. As in the arrangement shown in Fig. 1, the ignition unit includes a shell Il! in which an oscillation transformer having a primary winding 28 and a secondary winding insulated from each other by an insulating sleeve 3| are mounted about a core of insulating material 25 to supply high-voltage high-frequency current to a central ignition electrode 35. This central electrode is supported by the insulating core 25 to provide a spark discharge gap between it and cooperating spark discharge electrodes 43 supported in electrica] contact with the lower end il of the shell i5 by -an inturned lip portion 44. One terminal 33 of the transformer secondary winding 30 is electrically connected to the central discharge electrode 36, and the other terminal 32 is electrically connected to a terminal of the primary winding 21 and to a terminal screw 45 about which the upper end of the insulating core 25 is molded. This terminal screw is adapted to be electrically connected directly to one terminal of a quenched spark gap device so as to reduce the variations in capacitance and inductance due to the arrangement of the distribution leads or connections between the parts of the oscillatory circuit and the oscillation transformer. 'I'his connection is formed by a non-inductive linger spring 48 arranged in contact with the head of the screw and mechanically and electrically connected by a rivet 41 to a terminal cup 48 of a quenched spark gap device. This quenched spark gap device is provided with a second terminal cup 49 arranged on the opposite side of the device from the terminal cup 48 to provide an enclosing housing or casing for the quenched spark gap. The two terminal cups 48 and 49 are secured together and insulated from each other by an annular seal 58 of suitable material, such as glass, which is rigidly secured to the open ends of the cups by being molded thereabout. This quenched spark gap is formed between a pair of similar spark discharge buttons 5I and 52 provided with sparking faces 53 and 54 of suitable material, such as cadmium, and are provided with stem portions 55 and 55 which extend through openings in supporting and spacing members 51 and 58 and are secured thereto by upset rivet head portions 59 and 58. The spacing members 51 and 58 are held in predetermined spaced apart relationship by a spacing ring 5i formed of a suitable insulating material, such' as pressed mica, arranged between the adjacent inner edges thereof and firmly biased towards each other and against the sides of the ring 5I by pressure exerted on the outer edges thereof by the terminal cups 48 and 43 through locating rings 52 and 53. 'I'he spacing members 51 and 58 are held in their centered positions by a locating ring 84 of suitable insulating material, such as a h'eat hardenable resin, arranged about the outer cylindrical sur faces of the spacing elements 51 and 59. An insulating sleeve 55 extends between the outer surface oi' the quenched spark gap device and the inner portion of the barrel i0 to insure against electrical discharges therebetween. The termi nal cup 49 of the quenched spark gap device is electrically connected to a distributor lead 55 through a terminal screw 81 which contacts the terminal cup 59 and is held in position in a terminal element 58 electrically connected to one terminal of a capacitor 89. The capacitor 59 is electrically connected across the series circuit formed by the spark gap device and the primary winding 28 of the oscillation transformer. and one side thereof is electrically connected to the distributor lead 55 by the terminal 58 and the other side thereof is electrically connected to an enclosing electrically conductive casing 1li which forms an upper closure for the shell III. The casing 1li is secured in position by a cap nut 1I provided with an inturned flange 12 which extends over an outturned flange 13 formed on the lower end of the casing 1li to secure the casing flange 13 between the nut flange 12 and the upper edge of the barrel I8. The nut is drawn up tightly by threaded engagement of the lower threaded portion 14 thereof with a complementary threaded portion on the upper end of the barrel Iii. With this construction, the lengths of the connecting portions of the oscillation discharge circuit are reduced to a minimum and these connections are all formed by relatively non-inductive elements so that the inductances and capacitances of the oscillation circuit are essentially provided by the units designed for this purpose. With such a construction, a standard 40 ignition unit having a fixed oscillation circuit can be provided for all of the cylinders and for all of the ignition units of each cylinder and the different lengths of the distributor leads have a minimum effect on the oscillation of the circuit.

In Fig. 3, I have shown another embodiment of my invention in which a self -contained oscillation discharge circuit is provided for the ignition unit somewhat similar to that shown in Fig. 2. In this construction, the oscillation circuit includes a capacitor 59 arranged within the casing 10 and one side thereof is electrically connected to the casing 10 by a resilient non-inductive finger spring 15 arranged to bias the condenser 59 away from the upper end of the casing 1li. The other side of the condenser 59 is connected to the distributor lead 86 by the terminal element 58 and to the terminal cup 49 of the quenched spark gap device 'by the terminal screw 51, as in the construction shown in Fig. 2'. In this arrangement, the spark discharge device is made substantially the same as that in Fig. 2, and is formed with two similar terminal cups 48 and 49 which are sealed and held together by an annular glass element 55. In order to minimize the possibility of electrical discharge between different parts of the oscillation transformer and between parts of the oscillation transformer and the barrel i0, the oscillation transformer elements are formed and enclosed within an insulating member 16 of suitable insulating material, such as a lead borosilicate type glass which has a coefficient of thermal expansion substantially the same as that of the barrel I0. The barrel i0 and the windings of the oscillation transformer are formed of a material, such as nickel-iron, with substantially the same assainwinding 11 formed of a con having s few turns with one terminal 1l thereof electrically connected to a terminal I8 electrically connected to the terminal cup I8 of the quenched spark gap device, and provided with a terminal I8 electrically connected to the barrel Hl. A secondary transformer winding Il formed of a large number of turns is arranged within the primary winding 11 with one terminal B2 thereof electrically con' nected to the terminal 1! of the spark discharge device and the other terminal 83 thereof electrically connected to a central spark discharge electrode 84. The transformer primary and secondary windings I1 and BI and the discharge electrode B4 are supported in their desired relationship to each other by having parts thereof molded in theinsuleting element 18. Thus, the insulating element l5 provides a single high dielectric constant high temperature fusing point insulating material between all of the parts of the oscillation transformer and the barrel Ill and minimizes the possibility of discharges therebetween. As in the arrangement shown in the other figures, a plurality of discharge electrodes 85 is connected to the lower end of the barrel lil by an inturned lip 8S and held in spaced apart relationship relative to the central electrode all to provide the desired spark discharge gap between these electrodes. 'Ihe various elements of the ignition unit are resiliently held together within the barrel il) by the biasing action of the contact finger spring I5 to minimize the transmission of destructive forces and vibrations from the engine to the eiements forming the unit. In addition, it is desirable that the electrodes, the oscillation transformer, and the quenched gap discharge device should be held rigidly within the unit to provide the desired xed relationship between the discharge electrodes 84 and 85 and to minimize the possibility of breaking the electrical connections between the various units. This is obtained by rigidly clamping together these units by the cap nut 'll which transmits a clamping pressure through the inturned nut flange 'l2 to the casing nange 13 and a flange 81 formed on the outside of the insulating sleeve 65. The insulating sleeve $5 is arranged with a surface which firmly engages the outer surface of the spark discharge annular glass sealing element 50 and holds the spark discharge device rigidly against the upper end of the glass insulating member 1B and thereby rigidly holds the oscillation transformer and the central electrode 84 in position within the barrel l0. With this construction, a minimum number of parts and breakdown circuits is provided as well as a self-contained oscillation circuit within the ignition unit with substantially non-inductive short electrical connections between the various parts of the circuit.

While I have illustrated and described particular embodiments of my invention, modifications thereof will occur to those skilled in the art. desire it to be understood, therefore, that my invention is not to be limited to the particular arrangements disclosed, and I intend in the appended claims to cover all modifications which do not depart from the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. An ignition unit including a barrel, a spark electrode electrically connected to said barrel, a second spark electrode, an oscillation transformer having a primary winding and a secondary wlnding arranged in said barrel. means for electrically connecting one terminal of said secondary winding to said second spark electrodeI means for insulating said primary winding from said secondary winding, a central core of insulating material about which said secondary winding is arranged substantislly the full length of said secondary winding and in which said second electrode is mounted insulated thereby from said barrel and arranged to provide a spark discharge gap with said first-mentioned electrode, means for electrically connecting one terminal of said primary winding to said barrel, and means for providing an electrical connection between the other terminal of said transformer primary winding and a source of electrical power supply.

2. An ignition unit including a barrel, a spark electrode connected to said barrel, a second spark electrode, an oscillation transformer having a primary winding and a secondary Winding arranged in said barrel, means for electrically connecting one terminal of said secondary winding to said second spark electrode, means for insulating said primary winding from said secondary winding, a central core of high dielectric constent and high temperature fusing point insulating material about which said secondary Winding is arranged substantially the full length of said secondary winding and in which said second electrode is mounted insulated thereby from said barrel and arranged to provide a spark discharge gap with said first-mentioned electrode, means for electrically connecting one terminal of said primary winding to said barrel, and means for providing an electrical connection between the other terminals of said transformer primary and secondary windings and a source of electrical power supply.

3. An ignition unit including a barrel, a spark electrode electrically connected to said barrel, a second spark electrode, an oscillation transformer having a primary winding and a secondary winding arranged in said barrel, means for electrically connecting one terminal of said secondary winding to said second spark electrode, means for insulating said primary winding from said secondary winding, a central core of insulating materiai about which said secondary winding is arranged and in which said second electrode is mounted insulated thereby from said barrel and arranged to provide a spark discharge gap with said first-mentioned electrode, means for electrically connecting one terminal of said primary Winding to said barrel, and means including a quenched spark gap device arranged in and insulated from said barrel providing an electrical connection between the other terminal of said transformer primary winding and a source of electrical power supply.

4. An ignition unit including a barre1 a spark electrode electrically connected to said barrel, a second spark electrode, a transformer having a primary winding and a secondary winding arranged in said barrel, means for electrically connesting one terminal of said secondary winding to said second spark electrode, means for insulating said primary winding from said secondary winding, a central core of high dielectric constant insulating material about which said secondary winding is arranged and in which said second electrode is mounted insulated thereby from said barrel and arranged to provide a spark discharge gap with said first-mentioned electrode, means for electrically connecting one terminal of said primary winding to said barrel, and means including a quenched spark gap device providing an electrical connection between the other terminal of said transformer primary winding and a source of electrical power supply.

5. An ignition unit including a barrel, a spark electrode electrically connected to said barrel, a second spark electrode, an oscillation transformer having a primary Winding and a secondary winding arranged in said barrel. means for electrically connecting one terminal of said secondary winding to said second spark electrode, means for insulating said primary winding from said secondary winding, a central core of high dielectric constant high temperature fusing point insulating material about which said secondary winding is arranged and in which said second electrode is mounted insulated thereby from said barrel and arranged to provide a. spark discharge gap with said first-mentioned electrode, means for electrically connecting one terminal of said primary winding to said barrel, and means including a quenched spark gap device providing an electrical connection between the other terminal of said transformer primary and secondary windings and a source of electrical power supply.

6. An ignition unit including a barrelI an oscillation discharge circuit arranged substantially within said barrel and including a spark elec-Y trode electrically connected to said barrel, a second spark electrode, a transformer having a primary winding and a secondary winding arranged in said barrel, means for electrically connecting one terminal of said secondary winding to said second spark electrode, means including a single high dielectric constant insulating material element for insulating said primary winding from said secondary winding arranged to support said windings and said second electrode in said barrel and insulated therefrom and arranged to provide a spark discharge gap between said firstmentioned electrode and said second electrode, means for electrically connecting one terminal of said primary winding to said barrel, and means including a quenched spark gap device providing an electrical connection between the other terminal of said transformer primary winding and a source of electrical power supply.

7. An ignition unit including a barrel, an oscillation discharge circuit arranged substantially within said barrel and including a spark electrode electrically connected to said barrel, a second spark electrode, a transformer having a primary winding and a secondary winding arranged in said barrel, means for electrically connecting one terminal of said secondary winding to said second spark electrode, means including a single high dielectric constant insulating material element lor insulating said primary winding from said secondary winding arranged to support said windings and said second spark electrode in said barrel and insulated therefrom and arranged to provide a spark discharge gap between said first-mentioned electrode and said second electrode, means for electrically connecting one terminal of said primary winding to said barrel, and means for providing an electrical connection between the other terminal oi said transformer primary winding and a source of electrical power supply.

8. An ignition unit including a barrel, a spark electrode electrically connected to said barrel, a second spark electrode, a. transformer having a primary winding and a secondary winding arranged in said barrel, means for electrically connecting one terminal of said secondary winding to said second spark electrode, means including a single high dielectric constant insulating material element for insulating said primary winding from said secondary winding forming a central bore forsaid secondary winding and in which said second electrode is mounted insulated thereby from said barrel and arranged to provide a spark `discharge gap with said firstmentioned electrode, means for electrically connecting one terminal of said primary winding to said barrel. means for providing an electrical connection between the other terminal of said transformer primary winding and a source of electrical power supply, and a capacitor in said barrel electrically connected to said barrel and to said source of electrical power supply.

9. An ignition unit including a barrel of electrically conductive material, a spark electrode electrically connected to said barrel, a second spark electrode, an oscillation transformer having a primary winding and a secondary winding arranged in said barrel, means for electrically connecting one terminal of said secondary winding to said second spark electrode, means including a single high temperature fusing point insulating material element for insulating said primary winding from said secondary winding arranged to support said windings and said second electrode in said barrel and insulated therefrom and arranged to provide a spark discharge gap between said mst-mentioned electrode and said second electrode, said barrel and said insulating material element having substantially the same thermal coefficient of expansion, means for electrically connecting one terminal of said primary winding to said barrel, and means for providing an electrical connection between the other terminal of said transformer primary winding and a source of electrical power supply.

10. An ignition unit including a barrel, an oscillation discharge circuit arranged substantially within said barrel and including a spark electrode electrically connected to said barrel, a second spark electrode, an oscillation transformer having a primary winding and a secondary winding arranged in said barrel, means for electrically connecting one terminal of said secondary winding to said second spark electrode, means for insulating said primary windlng from said secondary winding, a central core of insulating material about which said secondary winding is arranged and in which said second electrode is mounted insulated thereby from said barrel and arranged to provide a spark discharge gap with said first-mentioned electrode, means for electrically connecting one terminal of said primary winding to said barrel, means including a quenched spark gap device providing an electrical connection between the other terminal of said transformer primary winding and a source of electrical power supply, and a capacitor electrically connected to said barrel and to said source of electrical power supply across said circuit formed by said quenched spark gap device and said transformer primary winding,

ll. An ignition unit including a barrel, an oscillation discharge circuit arranged substantially within said barrel and including a spark electrode electrically connected to said barrel, a second spark electrode, a transformer having a primary winding and a secondary winding arranged in said barrel, means for electrically connecting one terminal of said secondary winding to said second spark electrode. means including a single high dielectric constant insulating material element for insulating said primary winding from said secondary winding arranged to support said windings and said second electrode in said barrel and insulated therefrom and arranged to provide a spark discharge gap between said rust-mentioned electrode and said second electrode, means for connecting one terminal of said primary winding to said barrel, means including a quenched spark gap device providing an electrical connection between the other terminal oi said transformer primary winding and a source of electrical power supply, and Va capacitor electrically connected to said barrel and to said source of electrical power supply across said circuit formed by said quenched spark gap device and said transformer primary winding.

12. An ignition unit including a barrel, an oscillation discharge circuit arranged substantially within said barrel and including a spark electrode electrically connected to said barrel, a. second spark electrode, a transformer having a primary winding and a secondary winding arranged in said barrel, means for electrically connecting one terminal of said secondary winding to said second spark electrode. means including a single high dielectric constant insulating material element for insulating said primary winding from said secondary winding forming a. central core for said secondary winding and in which said second electrode is mounted insulated thereby from said barrel and arranged to provide a spark discharge gap with said iirst-mentioned electrode, means for connecting one terminal of said primary winding to said barrel, means including a quenched spark gap device providing an electrical connection between the other terminal of said transformer primary winding and a source of electrical power supply, and a capacitor electrically connected to said barrel and to said source of electrical power supply across said circuit formed by said quenched spark gap device and said transformer primary winding.

MYRLE O. MARSH.

DISCLAIMER 2,392,l7l.-Mfyrle 0. Marsh, Fort Wayne,

Company.

Ind. IGNITION Uma'. 1, 1946. Disclaimer ied Jan. 18,*1946, by the asslgnee,

Patent dated Jan. General Electric Hereby enters this disclaimer to claims l, 2, 3, 4, 5, and l0 of said patent.

[Oficial Gazette February 26, 1.946.]

ing to said second spark electrode. means including a single high dielectric constant insulating material element for insulating said primary winding from said secondary winding arranged to support said windings and said second electrode in said barrel and insulated therefrom and arranged to provide a spark discharge gap between said rust-mentioned electrode and said second electrode, means for connecting one terminal of said primary winding to said barrel, means including a quenched spark gap device providing an electrical connection between the other terminal oi said transformer primary winding and a source of electrical power supply, and Va capacitor electrically connected to said barrel and to said source of electrical power supply across said circuit formed by said quenched spark gap device and said transformer primary winding.

12. An ignition unit including a barrel, an oscillation discharge circuit arranged substantially within said barrel and including a spark electrode electrically connected to said barrel, a. second spark electrode, a transformer having a primary winding and a secondary winding arranged in said barrel, means for electrically connecting one terminal of said secondary winding to said second spark electrode. means including a single high dielectric constant insulating material element for insulating said primary winding from said secondary winding forming a. central core for said secondary winding and in which said second electrode is mounted insulated thereby from said barrel and arranged to provide a spark discharge gap with said iirst-mentioned electrode, means for connecting one terminal of said primary winding to said barrel, means including a quenched spark gap device providing an electrical connection between the other terminal of said transformer primary winding and a source of electrical power supply, and a capacitor electrically connected to said barrel and to said source of electrical power supply across said circuit formed by said quenched spark gap device and said transformer primary winding.

MYRLE O. MARSH.

DISCLAIMER 2,392,l7l.-Mfyrle 0. Marsh, Fort Wayne,

Company.

Ind. IGNITION Uma'. 1, 1946. Disclaimer ied Jan. 18,*1946, by the asslgnee,

Patent dated Jan. General Electric Hereby enters this disclaimer to claims l, 2, 3, 4, 5, and l0 of said patent.

[Oficial Gazette February 26, 1.946.]

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