US3898972A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ignition system for an internal combustion engine with automatic timing shift
Assignee: Robert Bosch GmbH
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Filing: 1973-11-15
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Granted: 1975-08-12
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Expires: 1993-11-15
Abstract
Abstract A timing pulse generator supplies the control current circuit of an electronically controlled switching element in the main current circuit of the ignition system over a full wave rectifier of which one half-wave branch includes a Zener diode preventing rectification unless the voltage exceeds its threshold value. The timing pulse generator provides a pair of succeeding pulses of opposite polarity at the end of each spark timing interval, the second pulse being of smaller amplitude. The Zener diode blocks the first pulse from the output of the rectifier at low engine speeds, so that the second pulse controls the timing. At intermediate engine speeds the first pulse overcomes the Zener diode voltage and takes over control of the timing, producing a jump advance of the spark timing. At high engine speeds a parallel combination of a capacitor and a resistor prevents the second pulse produced by the timing generator from interfering with the prompt quenching of the electronically controlled switching element in the main current circuit of the ignition system, because during the short timing interval the capacitor does not discharge fully through the resistor. By means of a switch, the first timing pulse can be loaded down to transfer the timing to the second pulse at high speeds during conditions when more complete combustion can thus be provided without sacrifice of needed power.
Inventors
- 👤 Georg Haubner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 10:47
CPC Classifications
F; F02; F02P; F02P1/00; F02P1/08; F02P1/086
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
255 words
An ignition system for an internal combustion engine, comprising: an ignition coil having a primary winding and a secondary winding; a semiconductor switching element having a control electrode leading to a control path therein and having a switched path in circuit with said primary winding of said ignition coil; at least one spark plug in circuit with said secondary winding of said ignition coil; a mechanically driven ignition timing pulse generator of the kind producing two electrical pulses of opposite polarity in quick succession for each spark cycle, arranged so that the first of said two pulses has the greater amplitude; a full wave rectifier in circuit with said timing pulse generator and said control path of said semiconductor switching element, so as to apply both of said pulses to said control path of said semiconductor switching element in the polarity required for switching said semiconductor switching element on; a voltage threshold diode means interposed in the path of said full wave rectifier for unbalancing the output thereof in such a way that when said timing pulse generator is driven at low speed, the first of said two pulses is effectively suppressed and the second is applied to said semiconductor switching element for ignition timing, and capacitor means bridged by a resistor in series with said control path of said semiconductor switching element of such electrical magnitudes that at higher driven speeds of said timing pulse generator, the second of said two pulses is counteracted and thereby effectively suppressed by the voltage across said capacitor.
Claim 2
Dependent Claim
255 words
An ignition system for an internal combustion engine, comprising: an ignition coil having a primary winding and a secondary winding; a semiconductor switching element having a control electrode leading to a control path therein and having a switched path in circuit with said primary winding of said ignition coil; at least one spark plug in circuit with said secondary winding of said ignition coil; a mechanically driven ignition timing pulse generator of the kind producing two electrical pulses of opposite polarity in quick succession for each spark cycle, arranged so that the first of said two pulses has the greater amplitude; a full wave rectifier in circuit with said timing pulse generator and said control path of said semiconductor switching element, so as to apply both of said pulses to said control path of said semiconductor switching element in the polarity required for switching said semiconductor switching element on; a voltage threshold diode means interposed in the path of said full wave rectifier for unbalancing the output thereof in such a way that when said timing pulse generator is driven at low speed, the first of said two pulses is effectively suppressed and the second is applied to said semiconductor switching element for ignition timing, and capacitor means bridged by a resistor in series with said control path of said semiconductor switching element of such electrical magnitudes that at higher driven speeds of said timing pulse generator, the second of said two pulses is counteracted and thereby effectively suppressed by the voltage across said capacitor.
Claim 3
Dependent Claim
48 words
An ignition system as defined in claim 1 in which said capacitor (28) and said resistor (29) are interposed between the output (21a, 46a) of said full wave rectifier (21, 46) and said control electrode (15a) of a semiconductor control rectifier (15) constituting the aforesaid semicondUctor switching element.
Claim 4
Dependent Claim
53 words
An ignition system as defined in claim 1 in which said timing pulse generator has a winding (20) and said winding is bridged by resistor means (27) in series with a diode (22) of said full wave rectifier which conducts during the second of said two pulses produced in said timing generator (18).
Claim 5
Dependent Claim
35 words
An ignition system as defined in claim 3 in which both ends (20a, 20b) of said winding (20) of said timing generator (18) are respectively connected to the input terminals of a bridge rectifier (21).
Claim 6
Dependent Claim
59 words
An ignition system as defined in claim 1 in which said timing generator (18) is provided with a winding (41) provided with a tap at an intermediate point of said winding, said tap being connected to ground or chassis, and in which the ends of said winding are each connected to a half-wave branch of said full wave rectifier.
Claim 7
Dependent Claim
58 words
An ignition system as defined in claim 5 in which the winding portions (41a, 41b) on either side of said tap (42) have different numbers of turns, the winding portion (41a) of the branch of said full wave rectifier in which said voltage threshold diode (44) is contained being the winding portion having the greater number of turns.
Claim 8
Dependent Claim
45 words
An ignition system as defined in claim 5 in which the winding portion (41b) on one side of said tap which is connected to the branch of said full wave rectifier that does not contain said voltage threshold diode is bridged by resistor means (49).
Claim 9
Dependent Claim
67 words
An ignition system as defined in claim 7 in which the winding portion (41a) on one side of said tap which is connected to the branch of said full wave rectifier that contains said voltage threshold diode means (44) is bridged by a series-connected combination of resistor means and switch (48) for reducing the amplitude of pulses produced by said winding portion under selected engine operation conditions.
References Cited (Backward Citations)
US3461345A
Cited
US3630185A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |