Diagnosis apparatus and method for an exhaust gas recirculation unit of an internal combustion engine
US5703285A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 2, 1996 |
| Grant date | Dec 30, 1997 |
| Priority date | — |
| Expiry date | Jul 2, 2016 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02M26/57
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A difference is obtained between a cylinder pressure during the compression stroke when an exhaust gas recirculation control valve is opened, and a cylinder pressure during the compression stroke when the exhaust gas recirculation control valve is closed. An estimated value for this difference is set from a cylinder pressure detected under the closed conditions and an exhaust gas recirculation proportion. When the difference is smaller than the estimated value, it is assumed that the exhaust gas recirculation quantity is not changing in accordance with open/close control, and the occurrence of a fault in the exhaust gas recirculation unit is thus judged.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.