Detroit Launches Really Integrated Powertrain

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Freightliner Cascadia Evolution

DETROIT, MI — Detroit Diesel Corporation has introduced the new and fully integrated Detroit Powertrain (IDP), which combines the Detroit DD15 engine with a Detroit DT12 transmission and Detroit axles front and rear in a Freightliner Cascadia Evolution or Western Star 5700. Orders will be taken in the third quarter of this year with production beginning in January 2015.

The company claims a fuel economy advantage of 5 to 7 percent in the Cascadia compared to an equivalent 2010 model without the DT12 and various new calibrations. Both 6×2 and 6×4 versions of the IDP will be on offer, the single-drive being the configuration able to hit that 7 percent mark.

The IDP is said to build on other technologies developed by parent-company Daimler Trucks North America (DTNA) by providing what it calls “state-of-the-art component communication that seamlessly work together.”

With everything designed and manufactured under one roof, DTNA says the individual components have been specifically tuned to work together to deliver maximum efficiency.

This is, of course, the European model.

According to Brad Williamson, manager, engine and component marketing for DTNA, Detroit’s axle engineers developed new axle ratios to match the engine rating. Engineers also tuned the transmission electronics to ensure all of the calibrations fit together perfectly to deliver the integration and performance customers demand.

With a new 2.41 axle ratio for the 6×4 configuration and a low 2.28 for the 6×2, downspeeding is the byword with the IDP.

The DD15 engine has a new ‘downsped’ rating of 400 hp and 1750 lb ft, which enables it to cruise at lower rpm regardless of road speed, ultimately reducing fuel consumption and friction. Think 1200 rpm instead of 1350. A new fuel map and shift strategy bring peak torque down to a very low 975 rpm, so driveability and performance will not suffer.

“Downspeeding improves fuel economy by shifting usable power and torque to a lower rpm range,” said Williamson. “Because we understand how important driver retention is to the real cost of ownership, Detroit engineers made sure to deliver a product that drivers will like.”

The proprietary Detroit Virtual Technician on-board diagnostic system is also integral to the IDP. The DD15 features the 1-Box emissions package that combines DOC, DPF, SCR catalyst and DEF doser, creating packaging flexibility for a variety of truck configurations. The DD15 also meets OBD13 and GHG14 standards.

The integrated DT12 automated manual transmission has the new Intelligent Powertrain Management (IPM) technology, which uses pre-loaded terrain maps and GPS to know the route ahead; it automatically adjusts transmission and engine functions resulting in an even smoother ride. Other features include eCoast, which allows the engine to operate at an idle of 500 rpm when engine power isn’t needed, and creep mode, which improves low-speed maneuverability.

“Whether approaching a grade, cresting a hill or traveling along rolling hills, Intelligent Powertrain Management makes sure the truck is carrying the most efficient momentum into the road ahead,” said Williamson. “The DT12 transmission is the critical link between the engine and the axles, and with the addition of the IPM, we are providing a seamless solution that has a direct impact on fuel savings.”

The 6×2 Detroit axle configuration incorporates a non-driven tag axle on the tandem, reducing total weight by almost 400 lb.

A new Demand Detroit app will be available for Android and iOS devices in early June at

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Rolf Lockwood is editor emeritus of Today's Trucking and a regular contributor to

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