US2638565A - Electric spark ignition apparatus for internal-combustion engines - Google Patents

Description

May 12, 1953 J LAIRD 2,638,565

. ELECTRIC SPARK IGNITION APPARATUS FOR INTERNAL-COM TION ENGINES Filed Jan. 1950 Patented May 12, 1953 ELECTRIC SPARK IGNITION APPARATUS FOR INTERNAL-COMBUSTION ENGINES John Andrew Laird, Coventry, England, assignor to Joseph Lucas Limited, Birmingham, England Application January 24, 1950, Serial No. 140,191 In Great Britain February 7, 1949 6 Claims.

This invention has for its object to provide improved electric spark ignition apparatus, of the kind in which a condenser, or each of a plurality of condensers, is charged from a magneto, ignition coil or like energy source, and subsequently discharged across a sparking plug after a predetermined voltage has been attained.

The invention comprises a system in which between the energy source, a condenser or condensers, and the sparking plugs, is arranged a distributor adapted to effect charging of the condenser Or each condenser across a gap, and to effect discharge across an associated gap.

In particular, the invention comprises for use in a system as defined in the preceding paragraph, a distributor consisting in part of a rotary member adapted to efiect the condenser charging and discharging operations across different gaps in the desired sequence.

In the accompanying drawings, Figures 1, 2, 3 and 4 are diagrammatic views illustrating four typical embodiments of the invention.

In one arrangement as represented in Figure l for producing sparks at each in turn of four sparking plugs a, there are employed four condensers b, each being adapted for connection to a sparking plug. The energy required for charging the condensers is supplied by a magneto, ignition coil or the like. In each of the examples illustrated the source comprises an ignition coil having a primary winding and a secondary winding (2, the primary winding being supplied with current from a battery or dynamo through a conventional interrupter e across which is connected the usual spark-suppressing condenser f.

In the example shown in Figure l, the connection of each condenser b in turn to the source and the associated sparking plug a is effected through a distributor which comprises a rotary arm 9 adapted to be connected to one end of the winding (1, and in the distributor are arranged at 90 apart four pairs of stationary electrodes h, a gap being provided between each pair. Also the arm 9 (during its rotation) provides a gap between its outer end and one of the electrodes in each pair 71..

The electrode in each pair with which the rotary arm g co-operates is connected to one side of a condenser, and the other electrode in each pair is adapted for connection to an associated sparking plug a. The other sides of the condensers are connected together and to the other end of the winding 11.

The arrangement is such that when the rotary arm 9 comes opposite any pair of stationary electrodes h, a charge is given to the associated condenser across the gap between the arm and the adjacent electrode, and when the voltage of the condenser reaches a predetermined amount, the condenser is discharged to the associated sparking plug across the gap between the said stationary electrode and its neighbouring stationary electrode, the action being repeated at each pair of stationary electrodes during the rotation of the distributor arm.

In the arrangement shown in Figure 2, a single condenser b is used, and in this case one of each of the stationary electrodes h are connected together and to one side of the condenser. The action is similar to that above described, excepting that the one condenser is charged and discharged each time the arm g comes opposite the stationary electrodes h. To ensure prompt action of each discharge gap between the electrodes h at the appropriate time, it is necessary that when a discharge occurs across the gap between the part g and any of the adjacent stationary electrodes h, it should ionise the gap between the stationary electrodes. This may be ensured in a variety of ways. formed in each of one of the electrodes h as shown. But preferably an arrangement as shown in Figure 3 is used.

In this arrangement four pairs of discharge electrodes h are mounted at equal distances apart in an insulating enclosure 2 (two only of which appear in the diagram), and connected to one in each pair of the electrodes n is an adjacently arranged fixed electrode a with which the arm 9' co-operates. The condenser b is charged across the gaps between 9* and a, and when the condenser is fully charged the discharge between gand 7 ionises the gap between the adjacent electrodes h, thus ensuring prompt action of the gap between the latter electrodes.

In another embodiment of the invention in which a single condenser is used and as shown in Figure 4, the rotary part of the distributor consists of an annular screen It having a gap in in its periphery. At the centre of the screen is arranged a charging gap formed by a pair of stationary electrodes n, and around the screen are disposed four equi-spaced discharging gaps formed by four pairs of electrodes h. One of the charging electrodes is connected to one end of .the winding d. The other electrode and one of each of the discharge electrodes h are connected together and to one side of the condenser b, the other side of the condenser being connected to the other end of the winding d. The other elec- For example a hole may be.

trodes of the discharge gaps are connected to the associated Sparking gaps a. It will be understood that in this example (as in that shown in Figure 3) there are four pairs of electrodes h and four sparking gaps a. The arrangement is such that the condenser b is caused to be charged across the charging gap n when the gap m in the rotary screen 70 is opposite any one of the discharging gaps h, and the spark across the charging gap serves to ionise the exposed discharging gap, so that the condenser can discharge across it when the required voltage is reached.

Preferably all the above described means are intended for use in an ignition system in which the sparking plugs are adapted'to operate at a relatively low voltage and have a permanent leak between the firing ends of their electrodes, each plug being preferably of the kind in which the firing ends of its electrodes are flush and are separated by a narrow annulus of insulating material.

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

1. An ignition distributor comprising in combination a plurality of pairs of fixed electrodes, the electrodes of each pair being separated by an ionisible gap, and means consisting at least in part of a rotary member whereby the gaps between said electrodes are exposible in sequence to an ionising eifect, said pairs of electrodes being -situated in spaced relationship about the rotational axis of said rotary member.

2. An ignition distributor comprising in combinati'on a plurality of pairs of fixed electrodes, the electrodes of each pair being separated by an ionisibl'e gap, and a rotary arm whereby the gaps between said electrodes are exposible in sequence to an ionising effect, said pairs of electrodes being situated in spaced relationship about the rotational axis of said arm, so that the latter serves during rotation to form a gap between itself and one electrode of each pair in turn.

3. An ignition distributor comprising in cornb-i'nation a plurality oipairs of 'fixed electrodes, the electrodes of each pair being separated by an io'nisible g'a'p, means electrically interconnecting one electrode of each pair, and a rotary arm whereby the gaps between said electrodes are exposible in sequence to an ionising effect, said pairs of electrodes being s'itnated in spaced relationship about the rotational axis of said arm so that the latter serves during rotation to form a gap between itself and each of the electrically interconnected electrodes in turn.

4. An ignition "distributor comp-rising in cornbination a plurality of pairs of fixed electrodes,

the electrodes of each pair being separated by an i-onisible gap, a plurality of additional fixed electrodes situated adjacent to said pairs of electrodes, means electrically connecting said additional electrodes respectively to one of each of said pairs of electrodes, and a rotary arm to cooperate with said additional electrodes for sequentially exposing the gaps between the first mentioned electrodes to an ionising effect, said pairs of electrodes and said additional electrodes being situated in spacedrelationship about the rotational axis of said rotary arm so that the latter serves during rotation to form a gap between itself and each of said additional electrodes in turn.

5. An ignition distributor comprising in co2nbin'at'i'on a plurality of pairs of fixed electrodes, the electrodes of each pair being separated by an ionisible gap, an additional pair of fixed elec trodes having a gap between them and arranged centrally between the other pairs of electrodes, and an ap'ertured rotary screen surrounding said additional electrodes to *co-operate therewith for sequentially exposing the gaps between the first mentioned electrodes to an ionising effect, the first mentioned pairs of electrodes being situated in spaced relationship around the rotational axis of said screen so that the latter serves during rotation to expose the first mentioned pairs of electrodes in turn to said additional pair of electrodes.

6. An electric spark ignition system comprising in combination a plurality of sparking plugs, a, condenser, a source of electrical energy for intermittently charging said condenser, electric circuital means connecting said condenser to said source and sparking plugs, and a distributor comprising a plurality of pairs of stationary electrodes forming parts of and providin ionisible gaps in said electric circuital means at positions between said condenser and sparking plugs, and means consisting at least in part of a rotary member whereby said gaps are sequentially exposible to an ionising effect so that successive charges received by said condenser from said source are discharged across said gaps in turn, said pairs of electrodes being situated in spaced relationship around the rotational axis of said relay member.

JOHN ANDREW LAIRD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,246,822 Shaw et al Nov. 13, 1917 1,418,518 Bell June 6, 192.2 1,907,515 Davis May 9, 1933 2,163,055 Olson June 20, 1939 2,489,780 Hooven l 1- Nov. 29, 1949 2,507,277 Smits i May 9, 1950

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