EXHAUST GAS CONTROL IN AN ENGINE HAVING A TWO-STAGE TURBOCHARGER

摘要

A control system (58) for controlling the extent to which a valve (50) selectively bypasses exhaust flow around one of two turbines (18T, 20T) in an engine exhaust system (14). A desired set-point (TCBC_DES) and the actual set-point (EBP_KPG) of operation of the valve are used to develop a set-point error (TCBC_ERR) for closed-loop control of the actual set-point (EBP_KPG). A data value for closed-loop gain (KP, KI) is selected from a schedule (164, 166) based on engine speed (N) and fueling (MFDES). The selected data values of closed-loop gain (KP, KI) and the set-point error data value (TCBC_ERR) are used to create a data value for a closed-loop output (TCBC_DTY_P, TCBC_DTY_I) that is used along with a feed forward parameter (TCBC_DTY_FF) to create a data value for a final output (TCBC_DTY_PIF) for forcing the actual set-point (EBP_KPG) to the desired set-point (TCBC_DES).