All others
The Diesel Oxidation Catalyst (DOC) is monitored to ensure it is capable of converting hydrocarbons and carbon monoxide. While entry conditions are met, a small quantity of fuel is post-injected late in the combustion cycle (similar injection timing as DPF regen). The actual exothermic efficiency is calculated from the temperature rise across the DOC and normalized by the expected exothermic efficiency (based on quantity of fuel injected), which results in a ratio having values between 0-1. If the normalized exotherm is below the threshold, a fault is indicated. No other preconditioning is required. The monitor entry conditions include:
The Diesel Oxidation Catalyst (DOC) is monitored to ensure it is capable of converting hydrocarbons and carbon monoxide. While entry conditions are met, a small quantity of fuel is post-injected late in the combustion cycle (similar injection timing as DPF regen). The actual exothermic efficiency is calculated from the temperature rise across the DOC and normalized by the expected exothermic efficiency (based on quantity of fuel injected), which results in a ratio having values between 0-1. If the normalized exotherm is below the threshold, a fault is indicated. No other preconditioning is required. The monitor entry conditions include:
- distance since last monitor completion 400km (248miles)
- time since entering normal Engine Operating Mode (EOM0) 300sec (transitioning from Regen or Catalyst Warmup) or 600sec (transitioning from Aftertreatment Overheat Mode)
- engine coolant temperature is greater than 70°C (158°F)
- engine speed greater than 1, 000 RPM
- engine torque greater than 50Nm
- OC inlet temperature 210-280°C (410-536°F)
Monitor requires 3 failing results in order to diagnose a failed DOC. In the event of a failing result, the monitor will immediately run again, bypassing the 400 km threshold above, until either a passing result or three consecutive failing results are obtained.