Catalyst preheating system

An internal combustion engine system, comprising:

• an internal combustion engine;
• a main exhaust aftertreatment system with a main catalytic converter configured to receive exhaust gas from the internal combustion engine;
• a catalyst preheating system with a recirculation passage, a pump, and an electrically heated catalyst (EHC) that includes a combined heating element and auxiliary catalyst, the EHC configured to selectively receive exhaust gas from the internal combustion engine, and wherein the auxiliary catalyst is a three-way catalyst (TWC);
• 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:
• determine a cold start, long idle, and/or low main catalytic converter temperature condition;
• activate the pump to draw the exhaust gas through the recirculation passage and the EHC, and create a looped flow of exhaust gas that facilitates minimizing exhaust gas flow and thermal energy loss through a tailpipe of the main exhaust aftertreatment system;
• and
• activate the heating element to rapidly heat the looped flow of exhaust gas.