EP0441603A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Misfire detection
Assignee: ZF International UK Ltd
•
Filing: 1991-02-05
•
Granted: —
•
Expires: 2011-02-05
Abstract
Abstract An engine misfire detector comprises an opto-electric sensor (6) for monitoring light produced by combustion inside a cylinder. The sensor (6) is connected to a variable gain amplifier (9) having a gain control circuit for controlling the amplifier gain. The output of the gain control circuit is compared with a threshold in a comparator (10) to provide a misfire detection signal. The transfer function of the gain control circuit includes an integral term. <IMAGE>
Inventors
- 👤 David Nutton
- 👤 Brian Graham Nicholson
- 👤 Adrian Leslie Trace
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 06:08
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/22; G; G01; G01M; G01M15/00; G01M15/04; G01M15/10
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
91 words
An apparatus for detecting misfire, comprising an opto-electric sensor for producing a signal representing light produced by combustion, and a comparator characterised by a variable gain amplifier (62-65) for amplifying the signal from the sensor (7), and a gain control circuit (66-84) connected between an output and a gain control input of the variable gain amplifier (62-65), the comparator (10) being arranged to compare an output signal of the gain control circuit (66-84) with a threshold, the gain control circuit (66-84) having a transfer function including an integral term (68-70, 72).
Claim 2
Dependent Claim
28 words
An apparatus as claimed in Claim 1, characterised in that the gain control circuit (66-84) includes a capacitor charging and discharging circuit (66-70, 72) providing the integral term.
Claim 3
Dependent Claim
42 words
An apparatus as claimed in Claim 2, characterised in that the capacitor charging and discharging circuit (66-70, 72) has a charging time constant less than or equal to 100 microseconds and a discharging time constant of the order of several hundred microseconds.
Claim 4
Dependent Claim
42 words
An apparatus as claimed in Claim 2 or 3, characterised in that the capacitor charging and discharging circuit (66-70, 72) is connected to an input of a high gain amplifier (71) whose output provides the output signal of the gain control circuit.
Claim 5
Independent Claim
91 words
An apparatus as claimed in any one of Claims 2 to 4, characterised in that the capacitor charging and discharging circuit comprises a capacitor (68), a discharging circuit (70, 72), and a charging circuit (66, 67, 69), the charging circuit comprising a differential amplifier (66) having a non-inverting input connected to the output of the variable gain amplifier (62-65) an inverting input connected to a first plate of the capacitor (68), and an output connected via a diode (67) and a resistor (69) to the first plate of the capacitor (68).
Claim 6
Dependent Claim
43 words
An apparatus as claimed in Claim 5 when dependent on Claim 4, characterised in that the discharging circuit comprises a further resistor (70), which is connected in parallel with the capacitor (68), and an input resistor (72) of the high gain amplifier (71).
Claim 7
Independent Claim
39 words
An apparatus as claimed in any one of the preceding claims, characterised in that the comparator (10) is connected to gating means (11) for passing a misfire detection signal during a time window corresponding to an engine combustion phase.
Claim 8
Dependent Claim
29 words
An apparatus as claimed in Claim 7, characterised in that the gating means (11) is arranged to generate the time window in response to a crankshaft position transducer (12).
Claim 9
Dependent Claim
30 words
An apparatus as claimed in Claim 7 or 8, characterised in that the gating means (11) is arranged to generate the time window in response to an ignition controller (5).
Claim 10
Independent Claim
30 words
An apparatus as claimed in any one of Claims 7 to 9, characterised in that the gating means is arranged to prevent passage of the misfire detection signal during deceleration.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.