Abstract: An engine system includes an engine including intake and exhaust camshafts, a transmission, a turbocharger including a compressor and a turbine, a surge valve to selectively bypass the compressor, a main exhaust aftertreatment system with a main catalytic converter, and a light-off catalyst bypass system with a bypass valve configured to selectively provide exhaust gas to a bypass passage and a bypass catalytic converter. An emissions control system includes a controller configured to monitor a temperature of the main catalytic converter to determine if the temperature is below a light-off temperature, move the bypass valve to an open position to provide exhaust gas flow through the bypass passage and bypass catalytic converter when the main catalytic converter is below the predetermined light-off temperature, and move the surge valve to an open position to enable intake air to bypass the compressor to minimize pressure loss during a cold catalyst mode.

Abstract: Hybrid powertrain control techniques include determining whether a regeneration event of a gasoline particulate filter (GPF) is necessary using a GPF loading model, commanding a full cylinder deactivation system to temporarily disable all of the cylinders of the engine instead of performing a deceleration fuel shutoff (DFSO) event of the engine and disabling fueling to the engine when the GPF regeneration event is not necessary, commanding the full cylinder deactivation system to keep all of the cylinders of the engine open and disabling fueling to the engine to perform the DFSO event when the GPF regeneration event is necessary, and controlling an electric propulsion motor to supply a requested drive torque, wherein keeping all of the cylinders of the engine open to perform the DFSO of the engine mitigates or eliminates insufficient regeneration of the GPF to thereby increase or extend its useful life.

Abstract: A control system and method utilize an exhaust oxygen (O2) sensor and a controller configured to operate a turbocharged engine in a scavenging mode, and while the operating the engine in the scavenging mode: command a target in-cylinder air/fuel ratio (FA) for achieving a target exhaust gas FA, adjust the measurement of the exhaust O2 sensor based on a scavenging ratio and the target in-cylinder FA to obtain a modified O2 concentration, adjust an exhaust system temperature modeled by a thermal model to obtain a modified exhaust system temperature, and adjust the target in-cylinder FA based on the modified O2 concentration and the modified exhaust system temperature.