US5027073A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High voltage ignition system monitoring circuit
Assignee: Robert Bosch GmbH
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Filing: 1990-03-01
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Granted: 1991-06-25
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Expires: 2010-03-01
Abstract
Abstract In order to protect catalytic converters from damage caused by continued engine operation with a malfunctioning ignition system, a monitoring circuit checks current in the ignition coil primary winding. Primary winding current (i) is transformed by a measuring circuit (11) into a test primary voltage (U pr ) which is fed to an evaluation circuit for comparison with ignition system supply voltage (U v ) from the battery. During each primary current pulse, an instantaneous value is sampled, preferably during the earlier half of the pulse, and when the instantaneous test voltage (U pr ) exceeds the supply voltage (U v ) by more than a predetermined amount, the evaluation circuit (10) generates an error or malfunction indication. The ignition system can then be serviced before the catalytic converter is ruined.
Inventors
- 👤 Ernst Kaller
- 👤 Karl-Heinz Kugler
- 👤 Christian Zimmermann
- 👤 Hans Koehnle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:34
CPC Classifications
F; F02; F02P; F02P17/00; F02P17/12
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
217 words
Circuit for monitoring a high voltage ignition system, of an internal combustion engine of a motor vehicle having an ignition coil (2) with primary (3) and secondary (12) windings and a series circuit, formed by said ignition coil primary winding (3) and a breaker switch (5), connected to a supply voltage (U v ), against short circuits, comprising a measuring circuit (11), having an input tapping said series circuit, which transforms current (i) in said ignition coil primary winding (3) into a test primary voltage (U pr ), and an output, said measuring circuit (11) including a shunt element (7) connected in a primary current path of said ignition coil (2); and an evaluation circuit (10) including a comparator having a first input connected to said output of said measuring circuit (11) to thereby receive said test primary voltage (U pr ) and a second input connected to said supply voltage (U v ), comparing said test primary voltage (U pr , with said supply voltage (U v ) by defining a reference value (U R ) corresponding to said supply voltage (U v ) and sampling at least an instantaneous value of said test voltage (U pr ), and generating an error signal whenever said sampled test voltage exceeds said supply voltage by a predetermined amount.
Claim 2
Dependent Claim
217 words
Circuit for monitoring a high voltage ignition system, of an internal combustion engine of a motor vehicle having an ignition coil (2) with primary (3) and secondary (12) windings and a series circuit, formed by said ignition coil primary winding (3) and a breaker switch (5), connected to a supply voltage (U v ), against short circuits, comprising a measuring circuit (11), having an input tapping said series circuit, which transforms current (i) in said ignition coil primary winding (3) into a test primary voltage (U pr ), and an output, said measuring circuit (11) including a shunt element (7) connected in a primary current path of said ignition coil (2); and an evaluation circuit (10) including a comparator having a first input connected to said output of said measuring circuit (11) to thereby receive said test primary voltage (U pr ) and a second input connected to said supply voltage (U v ), comparing said test primary voltage (U pr , with said supply voltage (U v ) by defining a reference value (U R ) corresponding to said supply voltage (U v ) and sampling at least an instantaneous value of said test voltage (U pr ), and generating an error signal whenever said sampled test voltage exceeds said supply voltage by a predetermined amount.
Claim 3
Dependent Claim
54 words
Circuit according to claim 1, wherein said measuring circuit (11) includes, connected in parallel to said shunt element (7), a filter circuit (9) formed by connecting in series a resistor (R) and a capacitor (C), and wherein voltage across said capacitor (U c ) is defined as said test primary voltage (U pr ).
Claim 4
Dependent Claim
36 words
Circuit according to claim 1 wherein the instant for sampling said instantaneous value is selected, with reference to the duration of a primary current pulse, to be within an earliest half of said primary current pulse.
Claim 5
Dependent Claim
23 words
Circuit according to claim 3, wherein said sampling instant is selected as a function of the configuration of the high voltage ignition system.
Claim 6
Dependent Claim
25 words
Circuit according to claim 1, wherein said evaluation circuit (10) generates an error signal when said instantaneous value exceeds said reference value (U R ).
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-24 | 1994-12-24 | 1995-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-24 | 1998-12-24 | 1999-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-24 | 2002-12-24 | 2003-06-25 | $7700.00 | Window Closed / Lapsed |