Air/fuel ratio estimation system for internal combustion engine
US5566071A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 3, 1995 |
| Grant date | Oct 15, 1996 |
| Priority date | — |
| Expiry date | Feb 3, 2015 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D2041/1433
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A system for estimating air/fuel ratios in the individual cylinders of a multicylinder internal combustion engine from the output of a single air/fuel ratio sensor installed at the exhaust system of the engine. A mathematical model is first designed to describe the behavior of the exhaust system which accepts the output of the air/fuel ratio sensor. An observer is designed to observe the internal state of the mathematical model and calculates the output which estimates the air/fuel ratios in the individual cylinders of the engine. In this configuration, when engine speed becomes high, the observer matrix calculation is discontinued, because it is difficult to ensure a time enough for calculation. Similarly, at a low engine load etc., the calculation is discontinued. Apart from the above, when a desired air/fuel ratio changes frequently such as when air/fuel ratio perturbation control is conducted, the desired air/fuel ratio is input to the observer as a second input. This will similarly be applied in a situation where the desired air/fuel ratio changes abruptly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.