Emission control system for internal combustion engine
US8893473B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 2013 |
| Grant date | Nov 25, 2014 |
| Priority date | — |
| Expiry date | Jun 19, 2033 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/1476
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An emission control system for an engine includes an upstream sensor provided upstream of a catalyst in a flow direction of exhaust gas, a downstream sensor provided downstream of the catalyst to detect an air-fuel ratio so that the air-fuel ratio approaches a target air-fuel ratio in a sub feedback control, a constant current supply portion which changes an output characteristic of the downstream sensor by applying a constant current on a pair of electrodes thereof. A characteristic control portion controls the constant current supply portion in the sub feedback control to advance a timing of lean detection of the downstream sensor when the air-fuel ratio is richer than the target air-fuel ratio, and to advance a timing of rich detection of the downstream sensor when the air-fuel ratio is leaner than the target air-fuel ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.