Method and system for exhaust aftertreatment

An exhaust system comprising:

• a main exhaust passage;
• a branched exhaust assembly with a first peripheral branch and a second peripheral branch branching from the main exhaust passage;
• a first sub-branch, a second sub-branch, and a fifth central sub-branch branching from the first peripheral branch;
• a third sub-branch, a fourth sub-branch, and a sixth central sub-branch branching from the second peripheral branch;
• wherein each of the first sub-branch, the second sub-branch, and the fifth central sub-branch are positioned on a first side of the main exhaust passage, and each third sub-branch, a fourth sub-branch, and a sixth central sub-branch are positioned on a second side of the main exhaust passage, the first side opposite to the second side.

An engine system comprising:

• an intake manifold;
• an exhaust manifold;
• a branched exhaust assembly with a first peripheral branch comprising a first sub-branch, and a second sub-branch, and a second peripheral branch comprising a third sub-branch, and a fourth sub-branch;
• a first four-way valve coupled to the exhaust manifold upstream of each of the first peripheral branch, and the second peripheral branch;
• a second four-way valve coupled to a first end of the first peripheral branch, and a third four-way valve coupled to a second end of the first peripheral branch;
• a fourth four-way valve coupled to a first end of the second peripheral branch, and a fifth four-way valve coupled to a second end of the second peripheral branch;
• turbine coupled to the first sub-branch;
• a diesel oxidation catalyst (DOC) coupled to the second sub-branch;
• a diesel particulate filter (DPF) coupled to the third sub-branch;
• a selective catalytic reduction (SCR) catalyst coupled to the fourth sub-branch;
• and
• a controller with computer readable instructions stored on non-transitory memory for:
• inferring temperature demand of each of the turbine, the DOC, the DPF, and the SCR, based on one or more of desired boost, engine temperature, DPF soot loading, and SCR catalyst NOx loading, and;
• when turbine temperature demand is higher than DOC, actuating each of the first valve, the second valve, and the third valve, to flow exhaust first through the turbine, when DPF temperature demand is higher than SCR catalyst, actuating each of the first valve, the fourth valve, and the fifth valve, to flow exhaust first through the DPF.