US2161605A - Ignition system - Google Patents

Description

J.. /YOLLES IGNITION SYSTEM Jun 6, 1939.

Filed March 13, 1955 @Imam MTQRNEY,

Patented June 6, 1939 f UNITI-ED fsrATES;

.,-P'Af'rENf-r oFFic-E 2,161,605 e Y l IGNITION SYSTEM JaeohYolles,v Paris,l Franccrassignor toRadio Corporation of America, a corporation of Delaware Application March 13, 1935, serial No. 10,190 i 5 claim. (ci. 12s-14s) An object of this invention is to provide anv ignition system especially adapted for a vehicle which is propelled by an internal combustion engine and so arranging it that itis substantially free from disturbing influences on any radio equipment such as a receiver, carried Aby the vehicle.

A still further object of the inventionis to mount the induction coil and the high tension distributor of such a vehicle within a metallic casing or housing which is located very close to the engine.

A still further object of the invention is to mount a choke coil-and condenser within such l5 a housing, these elements being so connected in thev primary circuit of the induction coil that radio frequencycurrents -arising within the primary circuit are preventedfrom getting out of the housing and more especially getting into the storage battery circuit. When an entirely closed casing is provided it has the further advantage of keeping water and moisture from getting into the coil, distributor and the other circuit elements 'mounted within the housing.

Still other objects of the invention will become apparent to those skilled in the art as the description thereof proceeds. For a better understanding of the invention, however, reference is made to the accompanying drawing in which the 30- single gure shows partly in cross section and partly diagrammatically, an embodiment of my invention. l

In the usual automobile ignition system the primary of the induction coil is usually mounted 35 some distance from the engine or distributor so that this circuit with the battery leads and connections to the circuit breaker forms a loop aerial of large area which is quite effective in radiating radio frequency currents produced by the spark 4o `at the circuit breaker. Also the secondary circuit including successively the several leads running from the distributor points to the spark plugs forms another loop circuit of large area which is effective in radiating the high frequency 45 currents generated at the spark plugs. It is found that the high frequency'energy generated by these circuits gets into a radio receiver mounted within the car or other vehicle by means of the battery connections when the receiver is oper- 50 ated from the car storage battery and such energy is also picked up by the antenna of the receiver to a greater or less extent. By means of my invention, these effects are substantially eliminated.

55 Referring now to the drawing, reference nu-v meral I indicates thecar or storage battery which is `connected bythe lead 3, key or lock switch 2, lead 4, radio frequency choke coil 6, and induction coil primary Winding B, lead 24, to the outer of the breaker contact points 22. The inner 5 breaker contact point is mounted in the usual manner von a spring 2| which is operated at the desired instant of explosion by the cam 20 mounted on the shaft I5, this shaft being suitably driven in any suitable manner from the timing or cam l0 shaft 32 as by the bevel gears 3|. A condenser 23 has its opposite terminals' connected respectively to the breaker points 2. The iron casting I6 in which shaft I5 is journalled carries molded rings I1 formed of Bakelite near its upper end in 15 which are inserted the stationary contacts I2 each of which is connected by a lead 26 with one of the spark plugs 30. The upper portion of the housing or support I6 is entirely covered by a thin metallic cover memberI or casing I 8 within 20 which the primary 8 and secondary coil 9 of the high tension induction coil are mounted. If desired an electrostatic metal shield I ilY may be mounted between the primary and secondary windings and be conductively connected to the casing I8 to prevent the transference `of radio frequency currents from the secondary to the primary winding by means of the capacity coupling therebetween. If desired, a suppressor resistor II or radio frequency choke coil may be inserted between the high potential end of the secondary winding and the distributor arm I3 which in its rotation contacts with or comes very close to the distributor points I2. Y

As a further means for assisting in the prevention of radiation of high frequency currents, I may provide a ground connection 21 between a point 28 on the cylinder head which is substantially-central with respect to the spark plugs of the engine and the casing I8. It will be under- 40 stood that the casting I6 is usually grounded to the engine framework as diagrammatically indicated by the lead I9.

As a further means of preventing interference by radio frequency currents in the external circuit connections, the lead wires 4, 26 and 21, may 'beshielding by a covering of copper braiding or secondary circuit 9 thus avoiding the use of a separate resistor for each spark plug. It will further be seen that by mounting the induction coil and the distributor directly adjacent to the engine the area of the loop circuit formed by the secondary coil 9, resistor Il and the spark plugwire 26 is kept at a minimum, thereby reducing the effect of any radio frequency currents which might ow in this circuit.

Having described my invention what I claim as novel and desire to secure by Letters Patent is:

l. In an ignition system for an engine having spark plugs, the combination of a separable metallic shielding casing mounted adjacent the engine, an induction coil mounted in said casing and having primary and secondary windings, means connecting said secondary Winding consecutively to the several spark plugs, a single impedance in said casing and connected in series with said secondary winding and having a suficiently high Value as to damp the ow of radio frequency currents in said Winding, means mounted in said casing for making and breaking the cur` rent through said primary winding and a rotatable shaft journaled in the base of said casing and having a rotor portion within said casing for operating said last named means.

2. In an ignition system for an enginefhaving spark plugs, the combination of a shielding casing having a closed metallic top portion and a separable metallic bottom portion, a shaft journalled in said bottom portion, means for rotating said shaft, a rotatable metallic arm Within said casing and secured to and insulated from said shaft, a plurality of distributor points located at spaced points around said casing .and having their ends closely adjacent the path of motion of said arm, leads connecting said distributor points to the respective spark plugs, a step-up transformermounted Within said casing, a connection including an element mounted within said shieldv ing casing, between one end of the secondary winding of said transformer and said metallic arm, said element presenting a high impedance for high frequency currents, means mounted within said casing for making and breaking the current through the primary winding of said transformer and a cam secured to said shaft Within said casing for operating said last named means.

3. In an ignition system for an engine having spark plugs, a metallic housing mounted adjacent the engine, a lead connecting said housing and said engine and arranged to provide a return path for high frequency currents passing through said spark plugs, an induction coil having primary and secondary windings mounted in said housing, a distributor mounted in said housing arranged to connect said secondaryA winding to the several spark plugs successively,` said last named connection being made to all of the several spark plugs through a single element mounted within the metallic housing, said element having a high impedance for high frequency currents, means mounted in said housing for making and breaking the current through said primary winding and a single rotatable shaft having separate operating members within said housing for operating said distributor. and said last named means respectively.

4. In an ignition system for an engine having spark plugs, a shielding casing mounted adjacent the engine, an induction coil having primary and secondary windings mounted in said casing, an electrostatic shield between said windings, a conductive connection between said shield and said casing, a distributor mounted in said casing and arranged to connectsaid secondary winding to the spark plugs successively, a switch mounted in said casing for making and breaking the current through said primary winding, a condenser mounted in said casing and having one side connected to one terminal of said primary winding and its other side to said casing, a shaft journaled in said casing and having a portion arranged to engage the movable -blade of said switch and a second condenser within said casing and having one side connected to the other terminal of said primary winding and its other side to the movable blade of said switch whereby said condensers, primary Winding and shaft form a loop circuit enclosed within said casing.

5. In an ignition system for an engine having spark plugs, the combination of a metallic housing having a removable metallic cover portion and a stationary metallic base portion, said housing being mounted adjacent the engine, an induction coil mounted within said housing and having primary and secondary windings, means brought into contact with each other for causing a sudden increase of current through said primary`winding.

JACOB YOILES.

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