Internal combustion engine system, method of determining occurrence of air-fuel ratio imbalance therein, and vehicle
US8939135B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 6, 2011 |
| Grant date | Jan 27, 2015 |
| Priority date | — |
| Expiry date | Nov 14, 2032 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/1454
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
When an engine is in a predetermined steady operating state, a gradient accumulation average value ΔAulsa corresponding to the amount of change in the air-fuel ratio AF, detected by an air-fuel ratio sensor, over the period of time from when an upper peak is reached, at which the direction of change in the air-fuel ratio AF is inverted to when a lower peak is reached, at which the subsequent inversion of the direction occurs, is calculated (S100 to S160) and, when the calculated gradient accumulation average value ΔAulsa is greater than a predetermined threshold value ΔAref1 that is determined in advance as an upper limit (absolute value) of the range, in which it may be determined that the air-fuel ratio is even between the cylinders of the engine (S165 to S175), it is determined that the engine is in an air-fuel ratio imbalance state, in which there is an imbalance in air-fuel ratio between the cylinders of the engine.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.