Every Diesel Truck Has a Chemical Plant Bolted Underneath
2 days ago
- #diesel-emissions
- #aftertreatment-system
- #euro-vi
- Modern Euro VI trucks feature a complex aftertreatment system that converts harmful diesel emissions into nitrogen, water vapor, and CO2.
- The system includes four catalysts, a ceramic particle filter, a chemical injection system, and up to 44 sensors monitoring temperature, pressure, and gas composition.
- Key components include the DOC (Diesel Oxidation Catalyst), DPF (Diesel Particulate Filter), SCR (Selective Catalytic Reduction), and ASC (Ammonia Slip Catalyst).
- The DOC oxidizes CO, HC, and converts NO to NO2, which is crucial for passive DPF regeneration and SCR efficiency.
- The DPF traps soot particles and regenerates passively (using NO2) or actively (via high-temperature oxidation).
- SCR uses AdBlue (urea solution) to convert NOx into nitrogen and water, with optimal performance between 250-450°C.
- Cold starts and urban driving cycles pose challenges, as the system requires high temperatures to function effectively.
- Euro 7 regulations will introduce stricter limits, including cold-start NOx sub-limits and extended durability requirements.
- Tampering with the aftertreatment system is illegal and harmful, increasing emissions of NOx and particulate matter.
- The system's complexity and cost (maintenance, AdBlue consumption) motivate some operators to delete components, despite legal and environmental consequences.