Method for monitoring components in an exhaust aftertreatment system and engine arrangement including exhaust aftertreatment system monitoring arrangement

An engine arrangement with an exhaust after treatment system (EATS) monitoring arrangement, comprising:

• an engine with an exhaust line;
• an EATS attached to the exhaust line, the EATS comprising, in order from upstream to downstream, a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), and a selective catalytic reduction catalyst (SCR);
• means for measuring a first O2 level at a first location between the DOC and the DPF;
• means for measuring a second O2 level at a second location downstream of the SCR;
• means for measuring a first NOx level at the first location;
• means for measuring a second NOx level at the second location;
• and
• a controller configured to calculate SCR efficiency based on the first and second NOx levels and to determine whether the DOC, the DPF, and the SCR are functioning properly based on:
• whether the first O2 level is within a first O2 target,
• whether the second O2 level is within a second O2 target, and
• whether SCR efficiency is within an SCR efficiency target.