US5426587A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Misfire discriminating method for an engine
Assignee: BACK-A-LINE Inc
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Filing: 1993-12-08
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Granted: 1995-06-20
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Expires: 2013-12-08
Abstract
Abstract A method of discriminating the misfire of a multicylinder engine for each cylinder (FIG. 1A), comprising the steps of discriminating a cylinder number (#i) at a present combustion stroke (S101); calculating a present momentum at the present combustion stroke, in a period in which no combustive work is done (S105); computing a second momentum at a second stroke preceding the present combustion stroke two times, in a period in which no combustive work is done (S106); averaging the present and second momentums (S107); deriving a first momentum at a first stroke preceding the present combustion stroke one time, in a period in which no combustive work is done (S107); taking a difference between the averaged momentum and the first momentum (S107); setting a misfire judgement level from a map of combustion conditions in a function of said first momentum and engine load data (S108); and comparing the difference with the misfire judgement level (S109), thereby to judge the misfire condition for each cylinder without being affected by a manufactural allowance.
Inventors
- 👤 Ryuichiro Imai
- 👤 Izuru Kawahira
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:36
CPC Classifications
G; G01; G01M; G01M15/00; G01M15/04; G01M15/11; F; F02; F02P; F02P17/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
128 words
A method for discriminating a misfire occurrence of an engine having a plurality of cylinders, comprising: detecting sequentially a plurality of engine speeds, each of said engine speeds being detected in a period after a combustion in each cylinder of said engine with respect to an ignition sequence of all cylinders; detecting a variation in said detected engine speeds; setting a misfire judgment level as a function of an engine parameter representing an operation condition of the engine; comparing said variation with said misfire judgment level; judging a misfire occurrence in one of said cylinders when said variation is larger than said misfire judgment level; and renewing said misfire judgement level according to a plurality of engine speeds sequentially detected during a fuel cutoff state of the engine.
Claim 2
Independent Claim
128 words
A method for discriminating a misfire occurrence of an engine having a plurality of cylinders, comprising: detecting sequentially a plurality of engine speeds, each of said engine speeds being detected in a period after a combustion in each cylinder of said engine with respect to an ignition sequence of all cylinders; detecting a variation in said detected engine speeds; setting a misfire judgment level as a function of an engine parameter representing an operation condition of the engine; comparing said variation with said misfire judgment level; judging a misfire occurrence in one of said cylinders when said variation is larger than said misfire judgment level; and renewing said misfire judgement level according to a plurality of engine speeds sequentially detected during a fuel cutoff state of the engine.
Claim 3
Independent Claim
149 words
A system for discriminating a misfire occurrence of an engine having a plurality of cylinders, comprising: engine speed detecting means for detecting sequentially a plurality of engine speeds, each of said engine speeds being detected in a period after a combustion in each cylinder of said engine with respect to an ignition sequence of all cylinders; variation detecting means for detecting a variation in said detected engine speeds; setting means for setting a misfire judgment level as a function of an engine parameter representing an operation condition of the engine; comparing means for comparing said variation with said misfire judgment level; judging means for judging a misfire occurrence in one of said cylinders when said variation is larger than said misfire judgment level; and renewing means for renewing said misfire judgement level according to a plurality of engine speeds sequentially detected during a fuel cutoff state of the engine.
Claim 4
Independent Claim
149 words
A system for discriminating a misfire occurrence of an engine having a plurality of cylinders, comprising: engine speed detecting means for detecting sequentially a plurality of engine speeds, each of said engine speeds being detected in a period after a combustion in each cylinder of said engine with respect to an ignition sequence of all cylinders; variation detecting means for detecting a variation in said detected engine speeds; setting means for setting a misfire judgment level as a function of an engine parameter representing an operation condition of the engine; comparing means for comparing said variation with said misfire judgment level; judging means for judging a misfire occurrence in one of said cylinders when said variation is larger than said misfire judgment level; and renewing means for renewing said misfire judgement level according to a plurality of engine speeds sequentially detected during a fuel cutoff state of the engine.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1998-06-19 | 1998-12-19 | 1999-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-06-19 | 2002-12-19 | 2003-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-06-19 | 2006-12-19 | 2007-06-20 | $7700.00 | Window Closed / Lapsed |