Air/fuel ratio control system including means to well time start of feedback
US4707241A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 28, 1986 |
| Grant date | Nov 17, 1987 |
| Priority date | — |
| Expiry date | Feb 28, 2006 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/1456
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The invention relates to a control system for feedback control of the air/fuel ratio in an internal combustion engine by using a solid electrolyte oxygen sensor to sense oxygen in the exhaust gas. The oxygen sensor is of the type having an oxygen concentration cell and an oxygen ion pump cell to which a pumping current is supplied to vary the partial pressure of oxygen in the exhaust gas admitted in a measurement space in the sensor. The pumping current is controlled so as to nullify a difference between the output voltage of the oxygen concentration cell and a target voltage. A signal derived from the controlled pumping current is used as an air/fuel ratio signal on the premise that a definite correlation exists between the magnitude of the pumping current and the oxygen concentration in the exhaust gas. To commence feedback control of the air/fuel ratio soon after starting the engine and after establishment of the definite correlation without unnecessary delay, the control system includes discrimination means for forming a judgment that the expected definite correlation has been established if the output voltage of the oxygen concentration cell surely falls within a predetermined…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.