π Case Study
Kubota M8560 β DOC Light-Off Failure Leading to Chronic DPF Clogging
DOC never reaching light-off temperature (β₯ 250Β°C); downstream DPF accumulating soot without oxidation assistance
ποΈ Project Overview
Rice farm with frequent low-load irrigation pumping in Arkansas
π― Challenge
DOC never reaching light-off temperature (β₯ 250Β°C); downstream DPF accumulating soot without oxidation assistance
π§ Design Approach
Exhaust flow path redesign β added insulated turbo downpipe + repositioned DOC upstream of turbo β enabled exothermic oxidation pre-turbo
π Design Diagram
AI-generated project design illustration
π Key Calculations
DOC Light-Off Energy Requirement
E = m_doc Γ Cp Γ ΞT
Result: 142 kJ
Achievable only with β₯ 320Β°C inlet temp at rated load
Exothermic Gain from Pre-Turbo Oxidation
Q_ox = αΉ_fuel Γ LHV Γ Ξ·_ox
Result: 8.3 kW
Enables self-sustaining DOC temp above 400Β°C
π Results
DOC light-off achieved within 90 sec of load application; DPF regen frequency dropped from hourly to once per 120 hrsπ‘ Lessons Learned
- β’DOC placement relative to turbo significantly impacts thermal inertia and light-off capability
- β’Low-load applications demand DOC thermal managementβnot just catalyst formulation
β Key Takeaways
- 1DOC placement relative to turbo significantly impacts thermal inertia and light-off capability
- 2Low-load applications demand DOC thermal managementβnot just catalyst formulation