Automated Calibration for Compressor Recirculation Valve Control 2017-01-0594
Turbocharger compressors are susceptible to surge – the instability phenomena that impose limitations on the operation of turbocharged engines because of undesired noise, engine torque capability constraints, and hardware strain. Turbocharged engines are typically equipped with a binary compressor recirculation valve (CRV) whose primary function is to prevent compressor surge. Calibration of the associated control strategy requires in-vehicle tests and usually employs subjective criteria. This work aims to reduce the calibration effort for the strategy by developing a test procedure and data processing algorithms. An automated calibration for CRV control is developed that will generate a baseline calibration that avoids surge events. The effort to obtain the baseline calibration, which can be further fine-tuned, is thereby significantly reduced. Procedures are developed for testing and analysis that combines a previously developed surge characterization method with unconstrained nonlinear optimization. An adaptive algorithm is also presented that can update the CRV control calibration online. The developed procedures are demonstrated on vehicle data and compared with manually obtained calibrations.