Cummins retains single DEF injector for 2027 X15 and X10 with twin SCR aftertreatment
Cummins will meet EPA 2027 heavy-duty emissions with the same single DEF injector as today, backed by a new twin-SCR aftertreatment that cuts back pressure 44%.
- up to 3%
- 44%
- more than 80%
- up to 800,000 miles
What Happened
Cummins will keep its proven single-dose diesel exhaust fluid (DEF) injector for the HELM X15 and X10 engines when they meet EPA model year 2027 heavy-duty emissions standards. The company says the single doser avoids the complexity and extra DEF consumption of dual-dosing designs used by some rivals. Cummins calls the system the EPA27 Twin Module Aftertreatment.
“If you are dual dosing, what that truly means is you are allowing your engine to emit a relatively high amount of NOx and then planning on reducing that all in the aftertreatment space. You need more DEF fluid than Cummins requires to do that and your fluid economy will suffer because of that.”
Twin SCR canisters with parallel exhaust flow replace a single longer canister, cutting back pressure by 44% and contributing to improved fuel economy. A maintenance-free electric heater powered by a dedicated alternator sits in front of the SCR, with a second heater at the diesel particulate filter (DPF) assembly; the battery-free system provides precise, on-demand heat and supports emissions reduction during startup and low-load operation. The X10's aftertreatment is a scaled-down version of the X15's, and inlet/outlet configuration options support a range of chassis installations.
44%percent
Twin SCR module with parallel exhaust flow vs a single longer canister.
“We put a heater right in front of our DPF/DOC, and we have another heater in front of our SCR. Compared to electric heat, engine exhaust is a little crude in the sense that the heat is created relatively far away and has to travel through the system and piping before arriving at the aftertreatment. With electric, we have on-demand heat when and where we need it.”
Cummins says the aftertreatment system adds no weight over the previous model and keeps maintenance intervals unchanged. V-band clamps allow quick replacement of the diesel oxidation catalyst (DOC) and DPF, with DPF filters engineered to last up to 800,000 miles. The DPF and DOC maintain the same catalyst volumes and meet more demanding particulate matter requirements. Fleet customers are relieved that the same doser and part number carry over, according to Hauswald.
Why this matters
Fleet operators keep familiar maintenance and avoid higher fluid costs, since DEF is over $4 a gallon and diesel over $5. The X15's up to 3% fuel-economy gain and 44% lower back pressure can cut total cost of operation. The system stays the same weight and keeps today's service intervals.
Terms in This Story
- DEF
- Diesel exhaust fluid, a urea-based liquid injected into exhaust to help convert NOx into harmless nitrogen and water.
- SCR
- Selective catalytic reduction, an emissions-control system that uses a catalyst and DEF to cut nitrogen oxide emissions.
- DPF
- Diesel particulate filter, a device that traps soot and ash from diesel exhaust.
- NOx
- Nitrogen oxides, pollutants formed during high-temperature combustion that contribute to smog and acid rain.
Summarised from the linked release; details can be imperfect — always verify against the original source.