Air-fuel ratio controller of internal combustion engine
US4958611A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 1, 1989 |
| Grant date | Sep 25, 1990 |
| Priority date | — |
| Expiry date | Mar 1, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/4067
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The air-fuel (A/F) ratio controller of an internal combustion engine related to the invention detects occurrence of abnormal condition in a heater on the basis of the resistance value of this heater which heats an oxygen sensor generating a specific voltage responsive to the difference of oxygen concentration between atmosphere and exhaust gas of the engine and of an oxygen pump allowing the pump current flow in order that the voltage can be the predetermined value. If abnormal condition arises in the heater, the A/F ratio controller stops fuel feedback control operation. The A/F ratio controller related to the invention forms a Wheatstone bridge circuit which includes the heater mentioned above and detects occurrence of an abnormal condition in the heater on the basis of the equilibrium condition of signal outputted from the Wheatstone bridge circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.