Abstract: A method is disclosed for preventing an underspeed event of a turbocharger. The method includes interpreting a turbocharger speed, a compressor differential pressure (CDP) and a turbocharger differential pressure (TDP). The method further includes calculating a thrust load capacity (TLC) based on the turbocharger speed, and calculating a current thrust load (CTL) based on the CDP and the TDP. The method further includes calculating a thrust margin based on the TLC and the CTL, and controlling an actuator in response to the thrust margin. Controlling the actuator includes maintaining the thrust margin to a thrust margin target, which may be a function of the turbocharger speed. The actuator is a turbine bypass valve, a compressor bypass valve, a variable geometry turbocharger position, an exhaust throttle and/or an exhaust gas recirculation valve that controls the turbocharger speed.

Abstract: An embodiment is an apparatus for providing thermal management of a diesel aftertreatment device. The apparatus includes an intake throttle, at least one exhaust gas recirculation (EGR) valve coupled to the intake throttle, a turbine bypass valve coupled to the at least one EGR valve and a control mechanism coupled to the intake throttle, the at least one EGR valve and the turbine bypass valve for selectively actuating at least one of the valves based on an engine operation profile.

Abstract: A method is disclosed for preventing an underspeed event of a turbocharger. The method includes interpreting a turbocharger speed, a compressor differential pressure (CDP) and a turbocharger differential pressure (TDP). The method further includes calculating a thrust load capacity (TLC) based on the turbocharger speed, and calculating a current thrust load (CTL) based on the CDP and the TDP. The method further includes calculating a thrust margin based on the TLC and the CTL, and controlling an actuator in response to the thrust margin. Controlling the actuator includes maintaining the thrust margin to a thrust margin target, which may be a function of the turbocharger speed. The actuator is a turbine bypass valve, a compressor bypass valve, a variable geometry turbocharger position, an exhaust throttle and/or an exhaust gas recirculation valve that controls the turbocharger speed.