US3874355A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ignition device for internal combustion engine equipped with protective device
Assignee: Hitachi Ltd
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Filing: 1973-08-08
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Granted: 1975-04-01
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Expires: 1993-08-08
Abstract
Abstract An ignition device for an internal combustion engine provided with a circuit for protecting the ignition device from thermal damage due to the current flowing across the ignition coil when the engine is stopped. The protective device consists of a charge-discharge circuit having a time constant larger than the ignition period. The charge-discharge circuit is reset by the pulses indicative of ignition timing. When the engine is stopped, the charge-discharge circuit produces an output after the lapse of time determined by its time constant due to the absence of the input pulse. By the output of the circuit the current flowing across the ignition coil is automatically interrupted.
Inventors
- 👤 Seiji Suda
- 👤 Yasunori Mori
- 👤 Shiro Ida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:21
CPC Classifications
F; F02; F02P; F02P15/00; F02P15/12; F02P3/00; F02P3/02; F02P3/04; F02P3/055; F02P3/0552; F02P3/0556
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
304 words
An ignition device for an internal combustion engine, comprising: input means to which pulses indicative of the ignition timing of an internal combustion engine are applied; first switching means being switched off at an ignition time in response to the output of said input means; an ignition coil comprising the primary coil and the secondary coil, said primary coil being connected in series with said first switching means between terminals for supplying a DC voltage, said secondary coil being connected with a spark plug; time constant means comprising a charge-discharge circuit consisting of a capacitor and a resistor, said charge-discharge circuit having a time constant sufficiently longer than the pulse interval of said pulses, said time constant means producing an output the value of which varies with the lapse of time from the time at which an output of said input means is applied thereto and which reaches a predetermined value after the lapse of time determined by the said time cOnstant; and second switching means for turning said first switching means off when the value of the output of said time constant means exceeds a predetermined level, said second switching means comprising a transistor, the emitter and collector of said transistor being connected to one terminal of said DC source and the input terminal of said first switching means, respectively, and the base of said transistor being connected to the output of said time constant means; said resistor and capacitor of said time constant means being connected in series between the base of said second switching transistor and said DC source, and a junction point of said resistor and capacitor being electrically connected with said input means through a first diode, the input terminal of said first switching means being electrically connected with the output of said input means through a second diode.
Claim 2
Dependent Claim
304 words
An ignition device for an internal combustion engine, comprising: input means to which pulses indicative of the ignition timing of an internal combustion engine are applied; first switching means being switched off at an ignition time in response to the output of said input means; an ignition coil comprising the primary coil and the secondary coil, said primary coil being connected in series with said first switching means between terminals for supplying a DC voltage, said secondary coil being connected with a spark plug; time constant means comprising a charge-discharge circuit consisting of a capacitor and a resistor, said charge-discharge circuit having a time constant sufficiently longer than the pulse interval of said pulses, said time constant means producing an output the value of which varies with the lapse of time from the time at which an output of said input means is applied thereto and which reaches a predetermined value after the lapse of time determined by the said time cOnstant; and second switching means for turning said first switching means off when the value of the output of said time constant means exceeds a predetermined level, said second switching means comprising a transistor, the emitter and collector of said transistor being connected to one terminal of said DC source and the input terminal of said first switching means, respectively, and the base of said transistor being connected to the output of said time constant means; said resistor and capacitor of said time constant means being connected in series between the base of said second switching transistor and said DC source, and a junction point of said resistor and capacitor being electrically connected with said input means through a first diode, the input terminal of said first switching means being electrically connected with the output of said input means through a second diode.
Claim 3
Dependent Claim
72 words
An ignition device according to claim 1, in which said input means comprises at least one switching transistor, the collector of which is connected to said time constant means and said first switching means through said first diode and said second diode, respectively, and when said pulse is applied to said input means, said switching transistor of said input means discharges said capacitor of said time constant means through said first diode.
Claim 4
Dependent Claim
92 words
An ignition device according to claim 1, in which said input means comprises a transistor monostable multivibrator, the collector of the transistor of said monostable multivibrator, which is normally in the off state and turned on by the application of an input pulse, is electrically connected with the inputs of said time constant means and said first switching means through said first diode and said second diode, respectively, and said capacitor of said time constant means is discharged through said first diode when an input pulse is applied to said input means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |