Apparatus for controlling an air-fuel ratio in an internal combustion engine
US4872117A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 14, 1987 |
| Grant date | Oct 3, 1989 |
| Priority date | — |
| Expiry date | Dec 14, 2007 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/04
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An air-fuel ratio control apparatus for an internal combustion engine supplies an output signal from an O.sub.2 sensor detecting the concentration of oxygen in the exhaust gas to an electronic control unit having a microcomputer, and a control valve of the carburetor is controlled by a control signal from the microcomputer so as to control the air-fuel ratio in a feedback manner. A desired upper limit value is set for the control signal and, when the control signal exceeds this upper limit value in a transient operating condition of the engine, when its operating state is shifted from an idling state to a partial operating state, the microcomputer promptly changes the rich air-fuel ratio to a proper value. According to a preferred form of the invention, the control constant of the air-fuel ratio correction value is set to a large value for only a predetermined period of time in the transient operating condition of the engine, thereby correcting and controlling the air-fuel ratio to a proper value in a feedback manner. In this way, the quantity of gases such as CO or the like in the exhaust can be minimized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.