Adaptive variable geometry turbocharger strategy

A turbocharger including a variable geometry controller, the turbocharger including a variable geometry member located in an airway of the turbocharger, an actuator operative through a range of actuation positions to move the variable geometry member through a first range of variable geometry member positions that extends between a hard-stop closed position and a hard-stop open position, and that includes a smaller, second range of variable geometry member positions corresponding to desired flow conditions intermediate the hard-stop closed position and the hard-stop open position corresponding to desired flow conditions, and a sensor configured for sensing actuation information indicating the actuation position of the actuator, comprising:

• a memory device operative for reading and writing information;
• and
• a processing device operative with the memory device to write and read positional information, the written and read positional information including a transfer function relating sensed actuation information to actual variable geometry member positions throughout the second range of variable geometry member positions;
• wherein the processing device is operative to intermittently direct the actuator to force the variable geometry member to a hard-stop position, to read the actuation information sensed by the sensor device with the variable geometry member forced to the hard-stop position, and to re-establish the transfer function based on the sensor information read with the variable geometry member at the hard-stop position.

An actuator for operation with a variable geometry turbine including a variable geometry member located in an inlet of the turbine, comprising:

• an actuation mechanism operative through a range of actuation positions to move the variable geometry member through a first range of variable geometry member positions that extends between a hard-stop closed position and a hard-stop open position, and that includes a smaller, second range of variable geometry member positions corresponding to desired flow conditions intermediate the hard-stop closed position and the hard-stop open position corresponding to desired flow conditions;
• a sensor configured for sensing actuation information indicating the actuation position of the actuator;
• a memory device operative for reading and writing information;
• and
• a processing device operative with the memory device to write and read positional information, including a transfer function relating sensed actuation information to actual variable geometry member positions throughout the second range of variable geometry member positions;
• wherein the processing device is operative to intermittently direct the actuation mechanism to actuate the variable geometry member to the hard-stop closed position, to read the actuation information sensed by the sensor device with the variable geometry member at the hard-stop closed position, and to re-establish the transfer function based on sensor information read with the variable geometry member at the hard-stop closed position.