Air-fuel ratio control system for engine
US5080072A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 1990 |
| Grant date | Jan 14, 1992 |
| Priority date | — |
| Expiry date | Dec 7, 2010 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/148
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An air-fuel ratio control system for an engine has an air-fuel ratio sensor which generates an output value which changes according to an air-fuel ratio in an air-fuel mixture fed to the engine. An upper preset value which corresponds to an output value of the air-fuel ratio sensor for an air-fuel ratio which is larger than a stoichiometric air-fuel ratio and a lower preset value which corresponds to an output value of the air-fuel ratio sensor for an air-fuel ratio which is smaller than the stoichiometric air-fuel ratio are set. They are respectively reduced and increased by a predetermined value at one time at regular intervals, and are shifted each time the output value of the air-fuel ratio sensor exceeds the upper preset value at that time and reduces below the lower preset value at that time, to the output value of the air-fuel ratio sensor at that time. It is determined that the air-fuel ratio sensor is abnormal when the difference between the upper and lower preset values becomes smaller than a predetermined reference difference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.