Misfire detection method based on a change in crankshaft rotation
US5506778A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 1994 |
| Grant date | Apr 9, 1996 |
| Priority date | — |
| Expiry date | Feb 3, 2014 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D2200/1015
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A misfire detection method is provided, which method makes it possible to accurately detect the occurrence/absence of misfire by eliminating a detection error in misfire detection. This error is caused by a vibrational increase or decrease of the rotational changing rate of a crankshaft after a misfire state occurs. A processor, which receives pulse outputs from a crank angle sensor, calculates in sequence angular accelerations D.omega..sub.n-2, D.omega..sub.n-1, D.omega..sub.n, and D.omega..sub.n+1 in crank angle areas which correspond to a preceding cylinder, two cylinders checked for misfire, and a succeeding cylinder, respectively. If the values D.omega..sub.n-1 and D.omega..sub.n n significantly decrease in comparison with the values D.omega..sub.n-2 and D.omega..sub.n-1, respectively, then it is tentatively determined that misfire has occurred in both cylinders checked. Then If the value D.omega..sub.n+1 significantly increases compared to the value D.omega..sub.n, then the restoration to the normal combustion state is confirmed, and the occurrence of misfire in the two cylinders checked is definitely determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.