Self-diagnostic apparatus for exhaust gas recirculating apparatus
US5337725A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 20, 1993 |
| Grant date | Aug 16, 1994 |
| Priority date | — |
| Expiry date | Sep 20, 2013 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF02D41/0055
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A self-diagnostic apparatus for determining whether an exhaust gas recirculating apparatus is in an abnormal condition. The exhaust gas recirculating apparatus includes a second negative pressure path for directly connecting an intake path to an EGR valve for bypassing a modulator, a second switching valve located in line with the second negative pressure path, and a control unit for controlling the second switching valve which fully opens and closes the EGR valve when a vehicle is decelerating. Pressure variations within the intake path are caused by the opening and closing action of the EGR valve. The pressure variations are detected by the intake path pressure sensor in order to determine a deteriorating condition of the exhaust gas recirculating apparatus in accordance with the detected pressure variation values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.