HYBRID VEHICLE RAPID CATALYST EXHAUST COOLING

A hybrid electric vehicle (HEV) includes an internal combustion engine and a motor/generator configured to drive the engine or be driven by the engine to generate electricity to charge a high voltage (HV) battery and/or drive an electric traction motor. The HEV includes an exhaust system, a HV system electrically coupling the HV battery and the electric traction motors, and a control system including a controller for monitoring an underhood environment of the HEV and performing a cooling operation to cool the exhaust system. The controller is programmed to determine if a temperature of the underhood environment, the internal combustion engine, and/or the exhaust system is above a predetermined threshold indicating a potential degradation of HV system performance, and operate the internal combustion engine in fuel shut-off to generate a flow of air to the exhaust system for cooling of the exhaust system to thereby cool the HV system.