Detroit debuts DT12 transmission series and updates DD15 engine

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Detroit’s updated DD15 engine includes up to 50% new componentry to provide performance enhancements

Detroit’s series of DT12 transmissions enable down-speeding capabilities for improved fuel efficiency while the updated DD15 engine features up to 50 per cent redesigned componentry to provide performance enhancements.

Enhancements to the Detroit DD15 engine and an expanded line-up of the Detroit DT12 automated manual transmission will benefit buyers of the new Freightliner Cascadia range of prime movers.

DT12 transmission

The DT12 transmission has evolved into the DT12 On-Highway Series to offer three purpose-built options to meet the needs of various on-highway applications.

At the top of the range is the DT12-HE transmission which is engineered to accommodate increasing customer adoption of down-speeding with faster rear axles ratios to achieve maximum powertrain fuel efficiency.

The DT12-HE boasts higher overall ratios for improved down-speeding and an improved oil system design, both contributing to increased efficiency.

Also included in the DT12 On-Highway Series, is the DT12-HL transmission, a lightweight carry-over option offering comparable efficiency and durability to the rest of the portfolio and intended for weight-sensitive applications.

Lastly, the DT12-H, a revised designation for the stalwart of the portfolio, retains the same characteristics that have made the DT12 a favourite of fleets small and large.

DD15 engine

The fifth generation DD15 engine has been updated and engineered with enhanced performance and fuel economy.

A rethink and the application of precision engineering principles combine to provide improvements including increased down-speeding, better combustion and a new swirl piston design.

With nearly 50 per cent new componentry for the DD15 and fine-tuning by the global team of Detroit engineers, the DD15 Gen 5 brings up to a three percent improvement in fuel efficiency from propulsion.

As an additional benefit of more efficient operation, the engine also stands to reduce carbon dioxide emissions.

A new ball bearing simple geometry turbocharger reduces friction and allows peak power and torque to be reached faster.

Peak power is reached at lower engine RPMs of 1,500rpm versus the prior generation’s 1,625rpm, and peak torque is achieved at 900rpm versus a previously rated 1,075rpm.

Modified inlet ports in engine cylinders and a new piston bowl shape combine to create a swirl effect that creates a fuel spray pattern for better atomisation.

Along with an ultra-high compression ratio, the new swirl design piston makes combustion cleaner and more efficient than the previous generation of the DD15.

The durability of many key components is improved thanks to reduced design complexity and increased robustness.

A new EPA GHG21-compliant after treatment system for the DD15 Gen 5 debuts a smaller unit design to reduce weight by more than 27kg while increasing nitrous oxide conversion and, dependent on duty cycle, allowing increased diesel particulate filter service intervals.