Air-fuel ratio control system for internal combustion engines
US5983874A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 14, 1998 |
| Grant date | Nov 16, 1999 |
| Priority date | — |
| Expiry date | Aug 14, 2018 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D2041/1433
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
An air-fuel ratio control system for an internal combustion engine includes an air-fuel ratio sensor arranged in the exhaust system of the engine. An ECU estimates the air-fuel ratio of a mixture supplied to each of the cylinders cylinder by cylinder in response to an output from the air-fuel ratio sensor, by using an observer for observing an internal operative state of the exhaust system, based on a model representative of the behavior of the exhaust system, and calculates cylinder-by-cylinder air-fuel ratio control amounts corresponding respectively to the cylinders for carrying out feedback control of the air-fuel ratio of the mixture supplied to each of the cylinders such that the estimated air-fuel ratio of the mixture supplied to each of the cylinders is converged to a desired value. Upper and lower limit values of the cylinder-by-cylinder air-fuel ratio control amounts are set according to at least one of an rotational speed change amount of the engine and atmospheric pressure, and the cylinder-by-cylinder air-fuel ratio control amounts are limited so as to fall within an allowable range defined by the upper and lower limit values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.