Method for exhaust-gas aftertreatment with reduced emissions

A drive for a motor vehicle, the drive comprising an exhaust-gas recirculation device and an internal combustion engine connected to the exhaust-gas recirculation device, the exhaust-gas recirculation device comprising:

• a turbine, wherein the turbine has an inlet connected to an exhaust manifold and wherein the turbine is designed to convert kinetic energy contained in an exhaust-gas flow through the exhaust manifold into rotational energy;
• an exhaust-gas aftertreatment device having an inlet connected to an outlet of the turbine, the exhaust-gas aftertreatment device configured to reduce a pollutant content in the exhaust-gas flow, the exhaust-gas aftertreatment device further comprising an electric grid heater arranged between the outlet of the turbine and the inlet of the exhaust-gas aftertreatment device and configured to heat the exhaust-gas flow;
• a medium pressure EGR loop including an inlet downstream of the electric grid heater and upstream of the exhaust-gas aftertreatment device, an outlet upstream of a compressor, and a medium pressure EGR valve;
• a high pressure EGR loop including an inlet upstream of the turbine, an outlet upstream of the compressor, a high pressure EGR valve, an EGR cooler, and an EGR cooler valve;
• a bypass line fluidically coupling the high pressure EGR loop with the medium pressure EGR loop, having an inlet downstream of the high pressure EGR valve and upstream of the EGR cooler and EGR cooler valve, and an outlet downstream of the medium pressure EGR valve and upstream of the compressor;
• and
• a temperature sensor arranged downstream of the electric grid heater and upstream of the exhaust-gas aftertreatment device and which measures a temperature of the exhaust-gas flow.

A method for engine emissions reduction, comprising:

• during a first condition, powering a grid heater using an energy storage device to raise an exhaust-gas temperature;
• during a second condition, injecting fuel to raise the exhaust-gas temperature;
• and
• during a third condition, maintaining the exhaust-gas temperature by outputting power to the grid heater, injecting fuel, recycling the exhaust-gas, and cooling recycled exhaust-gas with an exhaust-gas recycle cooler coupled upstream of a charge-air cooler, wherein recycling the exhaust-gas comprises diverting a portion of the exhaust-gas to one or more exhaust-gas recycle lines, wherein the one or more exhaust-gas recycle lines comprise a high-pressure exhaust-gas recycle stream directed through the exhaust-gas recycle cooler and a high-pressure exhaust-gas recycle valve upstream from the grid heater, and a mid-pressure exhaust-gas recycle stream and a mid-pressure exhaust-gas recycle valve downstream from the grid heater.