Daimler announces EPA 2027 compliant Detroit engines
23 February 2026
Detroit, the Daimler Truck North America’s powertrain brand, announced its new Gen 6 heavy-duty engine portfolio, comprised of the DD13, DD15 and DD16 engines. The engines comply with the US EPA’s 2027 emission standards utilizing the dual-stage SCR technology.
The Detroit Gen 6 DD13 and DD15 engines will be available beginning in January 2027, with Gen 6 DD16 production following in January 2028. The engines will be available for all heavy-duty Freightliner and Western Star trucks.
The Gen 6 DD13 engine (12.8 L displacement) will be available with power ratings of 410-525 hp and 1450-1850 lb-ft of torque. The respective figures for the DD15 (14.8 L) are 425-505 hp/1550-1900 lb-ft, and for the DD16 (15.6 L) 560-605 hp/1850-2050 lb-ft.
The Detroit Gen 6 engines update the previous generation’s design and incorporate new emission technologies to meet the EPA 2027 standards—the 2027 NOx limit (FTP) is 0.035 g/hp-hr, compared to the current limit of 0.2 g/bhp-hr. The updated features include:
- Miller cycle intake timing improves efficiency by reducing the work of compression, and lowers combustion temperatures to lower NOx emissions.
- An oil lubricated injection pump enables a simpler high-pressure common rail fuel system design and eliminates the need for amplified injectors. Direct pressure, non-amplified fuel injectors maintain consistent fuel delivery in a simplified design, improving reliability.
- A variable displacement oil pump regulates flow at low temperatures, feeding a lower pressure oil system to reduce power consumption.
- The asymmetric turbocharger adds a wastegate valve to precisely control pressure across a wider operating range. This also improves engine braking performance and maintains heat for regenerations.
- Detroit one-box aftertreatment system adds pre-SCR (light-off SCR) technology to reduce NOx with no impact to engine performance. The pre-SCR system is positioned on top of the existing aftertreatment unit, while the entire system fits the same space on the frame rail, keeping chassis upfit consistent from previous generations.
Detroit’s DD engine series was introduced in 2007, with successive generations launched in 2010 (Gen 2), 2013 (Gen 3), 2016 (Gen 4), and 2021 (Gen 5). To date, there have been 1.2 million heavy-duty Detroit engines sold for both on-highway and vocational applications. Around 200,000 engines are produced per year. Detroit engines are manufactured in the USA at the Redford, Michigan campus.
Source: Daimler Truck