Air-fuel ratio control system for internal combustion engine
US5797370A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 21, 1997 |
| Grant date | Aug 25, 1998 |
| Priority date | — |
| Expiry date | Feb 21, 2017 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D2250/21
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An air-fuel ratio control system for an internal combustion engine having a fuel injection valve for each cylinder and an electronic air control valve (EACV) for controlling intake air bypassing the engine throttle valve. When the target air-fuel ratio is switched over from a rich value to a lean value, the amounts of fuel injected into the cylinders, for example, #1, #2, #3 and #4 cylinders are controlled so that they are sequentially decreased at predetermined intervals, and the EACV is controlled to be opened stepwise. This causes a decrease in engine torque generated by the switching-over of the target air-fuel ratio to be offset by an increase in engine torque generated by an increase in amount of air drawn, thereby preventing the generation of a torque shock. At this time, the target opening degree of the EACV is corrected based on the magnitude of the interval and the magnitude of a loading of the internal combustion engine, thereby further effectively preventing the generation of the torque shock.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.