Dual function catalyst preheating and EGR system

An internal combustion engine system for an electrified vehicle, the engine system comprising:

• an internal combustion engine;
• an air intake conduit configured to receive intake air;
• an exhaust system with a main exhaust conduit and a main catalytic converter configured to receive exhaust gas from the internal combustion engine;
• an electric turbocharger assembly including a compressor and a turbine rotatably coupled by a shaft;
• a combined catalyst preheating/exhaust gas recirculation (EGR) system with a recirculation passage, a heating element, and a preheating/EGR valve configured to selectively allow flow through the recirculation passage, wherein the recirculation passage includes a first end fluidly coupled to the air intake conduit in a location downstream of the compressor, and an opposite second end fluidly coupled to the main exhaust conduit in a location upstream of the turbine;
• and
• a controller having one or more processors and a non-transitory computer-readable storage medium having a plurality of instructions stored thereon, which, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
• operating in a catalyst preheating mode, comprising:
• opening the preheating/EGR valve to allow intake air into the recirculation passage;
• and
• operating the electric turbocharger compressor to force intake air through the recirculation passage to the main exhaust conduit at the location upstream of the turbine, and through the heating element to rapidly heat the main catalytic converter to a predetermined light-off temperature;
• and
• operating in an EGR mode, comprising:
• opening a throttle to allow intake air to flow into the engine;
• opening the preheating/EGR valve to allow exhaust gas into the recirculation passage;
• and
• operating the internal combustion engine system to create a pressure differential to draw exhaust gas into the recirculation passage and recirculate the exhaust gas to the air intake conduit at the location downstream of the compressor.