Abstract: Butterfly valves of this invention generally comprise a flapper element that is rotatably disposed within an annular bore of a valve housing. The valve may be configured to provide an improved degree of gas flow control sensitivity from a closed to a partially opened position through the use of projections that extend radially inwardly from the housing bore, are positioned at diametrically opposed positions within the bore, and that are specifically configured to provide a gradual increase in gas flow across the valve as the flapper is moved from a closed position to a partially opened position. The butterfly valve may be configured having further projections that extend radially inwardly a distance therein, that are positioned at diametrically opposed positions in the bore, and that include faces that are sized and shaped to cooperate with respective opposed surfaces of the flapper to seal off gas flow within the bore when the flapper is placed into a closed position.

Abstract: An exhaust gas recirculation (EGR) system for an engine with a variable geometry turbocharger (18) incorporates a master rotary electric actuator (REA) (50) with a microprocessor controller (53) receiving condition signals (46, 48a-e) from sensors (48) associated with the turbocharger and the engine control unit (ECU) (54) and positioning the turbine inlet nozzle (44) geometry of the turbocharger in response to a predetermined matrix of the condition signals. A slave REA (52) is connected through an internal processing unit (58) to the controller to position an EGR valve (34). The processing unit provides an actual position signal to the controller which responds with a desired position signal based on the predetermined condition signal matrix. The processing unit engages the slave REA to position the EGR valve.

Abstract: An exhaust gas recirculation (EGR) system for an engine with a variable geometry turbocharger (18) incorporates a master rotary electric actuator (REA) (50) with a microprocessor controller (53) receiving condition signals (46, 48a-e) from sensors (48) associated with the turbocharger and the engine control unit (ECU) (54) and positioning the turbine inlet nozzle (44) geometry of the turbocharger in response to a predetermined matrix of the condition signals. A slave REA (52) is connected through an internal processing unit (58) to the controller to position an EGR valve (34). The processing unit provides an actual position signal to the controller which responds with a desired position signal based on the predetermined condition signal matrix. The processing unit engages the slave REA to position the EGR valve.