(19)
(11) EP 0 589 603 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
15.02.1995 Bulletin 1995/07

(43) Date of publication A2:
30.03.1994 Bulletin 1994/13

(21) Application number: 93307213.4

(22) Date of filing: 14.09.1993
(51) International Patent Classification (IPC)5: F02P 3/08, F02P 9/00, F02P 7/03, F02P 11/00
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 22.09.1992 US 949319
22.12.1992 US 994865

(71) Applicant: SIMMONDS PRECISION ENGINE SYSTEMS, INC.
Akron, Ohio 44334-0501 (US)

(72) Inventors:
  • Bonavia, Howard Vincent
    Groton, New York 13073 (US)
  • Geislinger, Dale Frank
    Norwich, New York 13815 (US)
  • Terzo, Michael John
    Bainbridge, New York 13733 (US)

(74) Representative: Foster, David Martyn et al
MATHISEN MACARA & CO. The Coach House 6-8 Swakeleys Road
Ickenham Uxbridge UB10 8BZ
Ickenham Uxbridge UB10 8BZ (GB)


(56) References cited: : 
   
       


    (54) Exciter circuits and methods with protective measures for solid state switches


    (57) An exciter for an internal combustion engine igniter plug (12) comprises a continuous AC charging circuit (20) and a discharge circuit (22). The discharge circuit (22) is connectable to the plug (12) and the charging circuit (20) includes a transformer (T1) having a primary winding connectable to an AC power source (28) and a secondary winding connected to the discharge circuit. The discharge circuit includes a storage capacitor (38) connected to the transformer secondary winding such that current induced in the secondary charges the capacitor (38) at a generally constant rate. A switching device (46) is connected in series between the capacitor (38) and the plug (12). A trigger circuit (52) triggers the switching device (46) in response to charge on the capacitor (38). The charging circuit (20) and trigger circuit (52) operate to maintain a generally constant spark rate. A current multiplier (76) is also provided to substantially increase the peak currents delivered to the plug (12). A clamping diode (150) is also provided in parallel with the storage capacitor (38) to prevent reverse currents and voltages due to resonance between the capacitor (38) and stray inductance.






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