Core Components (What Stays the Same)
The Cummins 2027 X15 aftertreatment system keeps the proven backbone intact.
The familiar DOC, DPF, single DEF dosing, and SCR architecture remain at the core—components that technicians already trust and know how to service.
Technician Takeaway: The system still uses the same architecture you already know and service.
Electric Inlet Heaters (What’s New)
One of the biggest updates to the Cummins 2027 X15 aftertreatment system is the addition of electric inlet heaters.
These heaters raise exhaust temperatures during cold starts, idle, and low‑load operation conditions notorious for high NOx output.
Key facts:
- Powered by the engine’s 48V generator (no battery required)
- Designed in‑house for durability
- No scheduled maintenance expected
Technician Takeaway: Heaters improve NOx control during low‑load operation without adding service complexity.
Twin‑Module Layout (Flexibility)
The system now uses two separate modules instead of one.
This modular approach gives fleets more installation options – whether stacked or rotated- making integration across different chassis far simpler.
Technician Takeaway: Modules can be stacked or rotated, giving fleets more installation options.
Dual‑Flow SCR (Efficiency)
The SCR catalyst now uses a parallel flow design.
Instead of one long path, exhaust gases split into two shorter paths.
Benefits:
- Lower back pressure → better fuel economy
- Improved heat retention → stronger NOx reduction
- More efficient “breathing” for the engine
Technician Takeaway: Parallel flow reduces strain on the engine while improving thermal management.
Maintenance (Simplified)
Despite the new technology, service remains straightforward.
Only two components require routine attention:
- DPF filter (now lasting up to 500,000 miles)
- DEF filter
If a module is damaged, fleets don’t need to replace the entire catalyst. Thanks to V‑band clamps, individual modules can be swapped out quickly and cost‑effectively.
Technician Takeaway: Only two serviceable parts, longer intervals, and modular replacement reduce downtime.
Compliance (Nationwide)
The Cummins 2027 X15 aftertreatment system is fully certified for all 50 states, covering both EPA and CARB requirements.
For fleet managers, that means one system, one certification, and no regional restrictions. Trucks can operate seamlessly across the country without worrying about mismatched standards or stickers.
Technician Takeaway: One system, one certification—trucks can operate seamlessly across the U.S.
Summary of changes
- Familiar DOC, DPF, DEF dosing, and SCR remain
- NEW: Electric heaters in DOC and SCR inlet
- Twin‑module catalyst layout improves installation flexibility
- Dual‑flow SCR enhances thermal efficiency
- Only two serviceable parts: DPF and DEF filters
- No heater maintenance expected
- Fully compliant across all U.S. states
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