Exhaust gas recirculation control system
US4690120A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 25, 1986 |
| Grant date | Sep 1, 1987 |
| Priority date | — |
| Expiry date | Feb 25, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49609
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
A closed loop system for controlling exhaust gas recirculation (EGR) in an automotive engine. An electrical program command signal from an on-board engine computer/controller actuator through a motor driven circuit, a stepper motor to turn an axial lead screw having a follower thereon connected to a rod for moving the valve poppet to control flow. An orifice plate with differential flow pressure taps is disposed in the EGR passage downstream of a flow control valve poppet. The differential pressure from the taps is sensed by a pressure responsive diaphragm. A stationary proximity sensor using an eddy current principle detects changes in position of the diaphragm and in response thereto generates an electrical feedback signal proportional to EGR flow through the orifice which compared with the command signal to generate a control signal for controlling the stepper motor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.