| 摘要 |
<p>A control valve (26) for an EGR system employs a variable pressure actuator (106) connected to a valve for (98) metering EGR flow and a differential pressure valve connected to supply actuation pressure to the actuator. The differential pressure valve (126) incorporates a proportional solenoid (94) connected to a pressure balancing piston (97) which receives EGR pressure on one side and exhaust flow pressure on the other. The piston (97) is connected to a shaft (130) having an orifice (128) positionable adjacent a pressure source (104) in a first position and a pressure vent (108) in a second position, an outlet of the orifice communicating with the pressure actuator. EGR control is accomplished by providing a signal to the proportional solenoid (94) which shifts the pressure balance point for the piston (97).</p> |
