Cylinder abnormality diagnosis unit of internal combustion engine and controller of internal combustion engine
US7487035B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 13, 2007 |
| Grant date | Feb 3, 2009 |
| Priority date | — |
| Expiry date | Nov 13, 2027 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/1454
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
It is determined whether an engine operating state is within a specified operating range. When the engine operating state is within the specified operating range, the air-fuel ratio of an i-th cylinder is estimated based on the detection value of the air-fuel ratio sensor, and a cylinder deviation, which is the deviation of an estimated air-fuel ratio from a reference air-fuel ratio, is computed. When this cylinder deviation becomes larger than a specified determination value, the processing of incrementing the count value of an abnormality counter is started at a point in time when a specified delay time elapses after the cylinder deviation becomes larger than the specified determination value. At a point in time when the count value of the abnormality counter becomes larger than a specified abnormality determination value, it is determined that the air-fuel ratio of the i-th cylinder is abnormal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.