The Detroit Diesel Dd15 Is The Result Of $1.5 Billion And Nearly Five Years of development, making it the largest investment ever made by a manufacturer to design an engine. Detroit Diesel is not embarrassed about that gigantic figure. In fact, the company is so proud of this replacement for the Series 60 that you'd think the 10-digit bill was a bargain-and after seeing the debut of the DD15, it's hard to argue.
Brand-New DesignThe 14.8L DD15 is not a stopgap engine thrown together to bandage an old platform and meet new emissions regulations for a couple of years. It's a clean-sheet design that was built to surpass the strict controls that will become law during the next few years-but that's not all. In addition to cleaning up the exhaust output, the engineers targeted fuel economy, noise, driveability, and responsiveness while aiming to improve on the massive power output of the classic Series 60.
A Flywheel Turbine?By inventing a new type of turbo compounding system, the DD15 engineers found a way to add 50 hp and still improve fuel economy by 5 percent. The system works by using a conventional Holset HX55 turbo without a wastegate that feeds into a unique "turbo compound axial power turbine" that transfers power directly to the engine flywheel. By scavenging exhaust heat that would normally fly out of the tailpipe, the "axial power turbine" is able to spin a small gearbox that helps create up to 100 lb-ft of torque when the engine is under a full load.
Amplified Common-Rail System (Acrs)The DD15 has a unique fueling system that's not quite HEUI (hydraulically-actuated electronic unit injection) and not a regular common rail. It allows full injection pressure at any engine speed, up to five injections per combustion cycle, and even has the ability to control the rate of fuel delivery during a single injection event. The ACRS uses a relatively low rail pressure that's increased to more than 30,000 psi inside the injectors. The DDEC vI engine electronics and dual solenoids inside each injector give the DD15 extreme flexibility during fueling, allowing it to provide strong and clean low-end torque along with the high power levels you'd expect from a modern common-rail diesel.
Integrated Jacobs BrakeInside the aluminum valve rocker box on top of the compacted graphite iron head, you'll find dual overhead camshafts. The aluminum cams are dedicated to either the intake or the exhaust valves and are hollow to reduce drivetrain weight and improve throttle response at all engine speeds. The cam on the exhaust side features an integrated Jacobs engine braking system that closes the exhaust valves to provide three levels of grade braking and cruisebrake operation on long, downhill slopes.
EGR And DPFThe complex fueling system of the DD15 helps to greatly reduce emissions, but an exhaust gas recirculation (EGR) system and diesel particulate filter (DPF) are necessary to meet current and future emissions regulations. To improve the old EGR system, the DD15 team designed an integrated coolant manifold to better reduce nOX while reducing the "fuel-consumption penalty" of a conventional EGR setup. The DPF system is much like the ones on current 3.4- and 1-ton pickups, but it also has a "fuel doser" injector nozzle that can spray raw fuel directly into the exhaust when the DPF is being regenerated to ensure all the trapped particles get burned off. To meet future regulations, the DD15 may be fitted with a urea-spraying selective catalytic reduction (SCR) system.
More PowerAll of the innovations that were incorporated into the DD15 help it achieve more power than its successor while running cleaner and using less fuel. Using both its turbos, the DD15 is able to produce 560 hp and 1,850 lb-ft of torque in the maximized configuration-that's about 50 hp and 200 lb-ft of torque more than the trusty Series 60.
|NEW vs OLD |
| ||DD15 ||SERIES 60 |
| TYPE ||Inline-six-cylinder ||Inline-six-cylinder |
| DISPLACEMENT ||906 ci (14.8L) ||858 ci (14.0L) |
| BORE X STROKE (IN) ||5.47 x 6.42 ||5.17 x 6.61 |
| COMPRESSION RATIO ||18.4:1 ||17.0:1 |
| TURBO(S) ||Dual fixed/flywheel ||Single variable |
| HEAD MATERIAL ||Compacted graphite iron ||Cast iron |
| BLOCK MATERIAL ||Cast iron ||Cast iron |
| POWER ||560 hp at 1,800 rpm ||515 hp at 1,800 rpm |
| TORQUE ||1,850 lb-ft at 1,100 rpm ||1,650 lb-ft at 1,100 rpm |
| EXHAUST BRAKE ||575 hp ||N/A |
| WEIGHT ||2,970 lbs. ||2,557 lbs. |
| B50 LIFE ||1.2 million miles ||850,000 miles |