US5268843A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Engine misfiring determining device
Assignee: Subaru Corp
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Filing: 1990-12-26
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Granted: 1993-12-07
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Expires: 2010-12-26
Abstract
Abstract The device for monitoring the combustion state of each cylinder is provided in a multi-cylinder engine and determining if combustion abnormality occurs in the cylinder. The misfiring determining circuit compares an engine speed of a previous interval with that of a current interval, calculates the speed variation of a cylinder between both intervals, and determines the misfiring level by comparing the variation with the misfiring determining level. A cylinder misfiring time counting circuit counts the misfiring time of each cylinder and informs a cylinder misfiring time calculating circuit of the counting result. The cylinder misfiring time calculating circuit serves to average the misfiring time. A cylinder abnormal misfiring determining circuit compares the average misfiring time with a predetermined misfiring time maximum value for detecting the abnormal misfiring in each cylinder.
Inventors
- 👤 Ryuichiro Imai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:37
CPC Classifications
F; F02; F02D; F02D41/00; F02D41/02; F02D41/14; F02D41/1497; F02D41/1498; G; G01; G01M; G01M15/00; G01M15/04; G01M15/11; F02D35/00; F02D35/02; F02D35/023; F02D35/024
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
268 words
A misfiring determining device for an engine including a device for monitoring a combustion state of each cylinder provided in a multi-cylinder engine and for determining an occurrence of abnormal combustion in the cylinder, comprising: calculating means for comparing a first engine speed for a first time interval before combustion with a second engine speed for a second time interval after combustion and for calculating an engine speed variation between said first engine speed and said second engine speed; misfiring determining means for comparing said engine speed variation with a misfiring determining level for determining a misfiring state; cylinder misfiring time counting means for counting number of times of the misfiring in the cylinder; operating cycle number counting means for counting the number of an operating cycle for calculating the engine speed variation of each cylinder; cycle number determining means for supplying an output when the operating cycle number counted by said operating cycle number counting means reaches a predetermined sampling cycle number; cylinder average misfiring time calculating means for calculating a current average number of times of misfiring based on said number of times of the misfiring counted by said cylinder misfiring counting means and a previous average number of times of the misfiring when the cycle number determining means supplies the output; and cylinder abnormal misfiring determining means for comparing said current average number of times of the misfiring given by said average misfiring time calculating means with a predetermined misfiring time maximum value and storing abnormal misfiring data when the current average number of times of the misfiring reaches the predetermined misfiring time maximum value.
Claim 2
Dependent Claim
268 words
A misfiring determining device for an engine including a device for monitoring a combustion state of each cylinder provided in a multi-cylinder engine and for determining an occurrence of abnormal combustion in the cylinder, comprising: calculating means for comparing a first engine speed for a first time interval before combustion with a second engine speed for a second time interval after combustion and for calculating an engine speed variation between said first engine speed and said second engine speed; misfiring determining means for comparing said engine speed variation with a misfiring determining level for determining a misfiring state; cylinder misfiring time counting means for counting number of times of the misfiring in the cylinder; operating cycle number counting means for counting the number of an operating cycle for calculating the engine speed variation of each cylinder; cycle number determining means for supplying an output when the operating cycle number counted by said operating cycle number counting means reaches a predetermined sampling cycle number; cylinder average misfiring time calculating means for calculating a current average number of times of misfiring based on said number of times of the misfiring counted by said cylinder misfiring counting means and a previous average number of times of the misfiring when the cycle number determining means supplies the output; and cylinder abnormal misfiring determining means for comparing said current average number of times of the misfiring given by said average misfiring time calculating means with a predetermined misfiring time maximum value and storing abnormal misfiring data when the current average number of times of the misfiring reaches the predetermined misfiring time maximum value.
Claim 3
Dependent Claim
201 words
The misfiring determining device for an engine, comprising: measuring means for measuring a first engine speed for a first time interval before a combustion in a specific cylinder of said engine and a second engine speed for a second time interval after said combustion; calculating means for calculating an engine speed variation between said first engine speed and said second engine speed; misfire determining means for determining a misfire state of said specific cylinder by comparing said engine speed variation with a preset misfiring determining level, thereby accurately determining that said misfiring occurs; counting means for counting up a number of times of said misfiring in each cylinder for a preset period when said misfiring is determined by said misfiring determining means; averaging means for calculating a present average value of the number of times of said misfiring by taking an average between a previous average value of the number of times of said misfiring and said number of times of said misfiring counted by said counting means; and abnormal combustion determining means for determining an abnormal combustion state in said specific cylinder when said present average of the number of times of said misfiring becomes larger than a preset value.
Claim 4
Dependent Claim
201 words
The misfiring determining device for an engine, comprising: measuring means for measuring a first engine speed for a first time interval before a combustion in a specific cylinder of said engine and a second engine speed for a second time interval after said combustion; calculating means for calculating an engine speed variation between said first engine speed and said second engine speed; misfire determining means for determining a misfire state of said specific cylinder by comparing said engine speed variation with a preset misfiring determining level, thereby accurately determining that said misfiring occurs; counting means for counting up a number of times of said misfiring in each cylinder for a preset period when said misfiring is determined by said misfiring determining means; averaging means for calculating a present average value of the number of times of said misfiring by taking an average between a previous average value of the number of times of said misfiring and said number of times of said misfiring counted by said counting means; and abnormal combustion determining means for determining an abnormal combustion state in said specific cylinder when said present average of the number of times of said misfiring becomes larger than a preset value.
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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) | 1996-12-06 | 1997-06-07 | 1997-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-12-06 | 2001-06-07 | 2001-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-12-06 | 2005-06-07 | 2005-12-07 | $7700.00 | Window Closed / Lapsed |