Exhaust system and method of operating the same

A system comprising:

• an exhaust discharge line configured to receive exhaust gases from an engine;
• a first junction disposed at a first location along the exhaust discharge line;
• a second junction disposed at a second location along the exhaust discharge line downstream of the first location and fluidically coupled to a tailpipe;
• an after-treatment system disposed between the first junction and the second junction, the after-treatment system configured to reduce pollutants comprising Nitrogen Oxides (NOx) in the exhaust gases from the engine using a catalytic converter;
• an exhaust recirculation line fluidically coupled to the first junction and the second junction of the exhaust discharge line,
• a pressurized exhaust storage tank disposed along the exhaust recirculation line;
• a first control valve disposed in the exhaust discharge line downstream of the second junction;
• a second control valve disposed in the exhaust recirculation line between the second junction and the pressurized exhaust storage tank;
• a third control valve disposed in the exhaust recirculation line between the pressurized exhaust storage tank and the first junction;
• wherein each of the first control valve, the second control valve, and the third control valve comprise butterfly valves having an aperture of configurable diameter occupying a state inclusively between open and closed;
• and
• an electronic control unit (ECU) comprising a memory and at least one processor, where the ECU is communicatively coupled to the after-treatment system, the first control valve, the second control valve, and the third control valve, and the processor is configured to execute commands stored on the memory comprising:
• executing a filling phase by at least partially closing the first control valve, opening the second control valve, and closing the third control valve to accumulate a portion of the exhaust gases in the pressurized exhaust storage tank, thereby increasing a tank pressure of the pressurized exhaust storage tank, and increasing a system pressure of the after-treatment system and pressure heating the catalytic converter,
• determining, with a pressure sensor, whether the tank pressure exceeds a predetermined pressure threshold,
• ending the filling phase by at least partially closing the second control valve and at least partially opening the first control valve, while maintaining the tank pressure, in response to the determination that the tank pressure exceeds the predetermined pressure threshold,
• measuring a temperature of the catalytic converter,
• determining a maximum predicted conversion capacity of the after-treatment system based, at least in part, on the temperature of the catalytic converter,
• determining whether the temperature of the catalytic converter exceeds a light-off temperature of the catalytic converter, and
• opening the third control valve to release the portion of exhaust gases in response to the determination that the temperature of the catalytic converter exceeds the light-off temperature,
• wherein the third control valve is opened to an aperture that provides a flow rate across a predetermined unit of time less than or equal to the maximum predicted conversion capacity of the after-treatment system.