Cold start catalyst bypass system

A method of operating an internal combustion engine system that comprises:

• an internal combustion engine including an intake camshaft and an exhaust camshaft;
• a transmission;
• a turbocharger including a compressor and a turbine;
• a surge valve to allow intake air to selectively bypass the compressor;
• a main exhaust aftertreatment system with a main catalytic converter configured to receive exhaust gas from the internal combustion engine;
• 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;
• and
• an emissions control system including a controller configured to operate in a cold catalyst mode, the method comprising:
• monitoring, by the controller, a temperature of the main catalytic converter to determine if the temperature is below a predetermined light-off temperature;
• moving, by the controller, 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
• moving, by the controller, the surge valve to an open position to enable intake air to bypass the compressor to minimize pressure loss during the cold catalyst mode.