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  • Detroit Diesel DD16; Detroit’s Biggest Compound Turbocharged Heavy Haul Engine

Detroit Diesel DD16; Detroit’s Biggest Compound Turbocharged Heavy Haul Engine

Detroit Diesel DD16

John Lehenbauer
Oct 6, 2017
Photographers: Courtesy of Manufacturer
Class 8 trucks are the workhorses of the highway. The heavy loads of cargo these rigs haul across interstates demand engines that can provide substantial amounts of reliable torque and horsepower. However, despite this need for big-time performance, today’s modern oil-burners can’t produce horsepower and torque only. They must also must meet strict economy and emissions standards in order to truly be viable—especially in the U.S.
Building a powerplant that is able to meet all the required contemporary benchmarks is not an easy task. Many different technologies must be employed. Detroit Diesel meets these expectations and surpasses them with its Detroit DD16, the biggest, cleanest, and highest-output diesel in the company’s 80 years of building engines.
Photo 2/6   |   The compound turbochargers on the Detroit DD16 convert thermal energy normally expelled through the exhaust system into usable energy by way of a second exhaust turbine mounted downstream of the primary turbo. The turbine uses the energy left in the exhaust to generate power that is transmitted through a hydraulic coupler to the crankshaft.
The DD16 is a state-of-the-art 15.6L monster that produces 600 hp and 2,050 lb-ft of torque while meeting all current emissions standards. As with most modern diesel engines, several different systems and components have to work in unison in order for the powerplant to function well. One system that plays a key part in the overall functionality of this oil-burner is Detroit’s second-generation amplified common-rail system. The ACRS operates at 38,000 psi (in the injector, to reduce stress on other fueling components), which is at the higher end of the pressures used on many common-rail fuel systems. The higher-pressure fuel is injected in variable patterns for precise delivery at the exact moment it is needed for optimal combustion. By optimizing delivery, the system improves performance and throttle response while lowering emissions, noise, vibration, and fuel consumption. The more precise combustion also reduces stress on internal components.
Further enhancing the DD16 is a unique compound-turbocharging system, which uses a turbocharger and secondary exhaust turbine mounted downstream of the turbo. This design recovers thermal energy that would typically be lost and turns it into additional power. The secondary turbine does this by using the heat energy from the exhaust to spin and create kinetic energy. The kinetic energy is transmitted through a hydraulic coupler to the crankshaft. This provides an increase in force without using additional fuel. The constant drive on the crankshaft also helps smooth out the engine’s rhythmic combustion and supplies usable torque across a broader power range.
Photo 3/6   |   The cutaway diagram details how the turbo feeds exhaust into the second turbine and the link between the turbine and the crankshaft via a hydraulic coupler.
A 24-valve cylinder head ensures the DD16 breathes properly. Valves are actuated by two geardriven overhead camshafts. One shaft actuates the 12 exhaust valves, and the other opens and closes the remaining intake valves. The head also has an integrated Jacobs engine brake with three settings for enhanced downhill control.
Another important innovation that brings the entire package together is Detroit Diesel electronic control. The system controls normal engine functions and allows an operator to manage fuel economy, engine performance, driving efficiency, and maintenance scheduling. It also helps drivers control speed and assists in passing, improves shifting techniques, and manages DPF regeneration. By precisely controlling the engine’s systems for improved efficiency, DDEC helps extend service intervals and reduces downtime.
All the different engine systems work in conjunction with an EGR and Detroit’s 1-Box exhaust-aftertreatment technology to meet 2016 OBD criteria and 2017 greenhouse-gas regulations for medium- and heavy-duty trucks. The 1-Box system consists of selective catalyst reduction, diesel oxidation catalyst, diesel particulate filter, and diesel exhaust fluid injection in one compact unit mounted downstream of the engine. The system’s efficiency (by reducing the amount of exhaust that needs to return to the cylinders) helps lessen demand on the EGR.

SPECIFICATIONS

Engine: Detroit Diesel DD16
Displacement: 15.6L (952 ci)
Engine Layout: I-6
Valvetrain: DOHC 24-valve
Bore x Stroke: 5.47 x 6.73 inches (139 x 171 mm)
Compression Ratio: 17:1
Head Material: Graphite iron
Block Material: Cast iron
Piston Material: Steel
Power: 600 hp
Torque: 2,050 lb-ft
Emissions: 2017 greenhouse gas regulations
Induction: Compound turbochargers
Exhaust: Cast iron
Intercooler: Air-to-air
Cooling System: Liquid-cooled
Fuel System: Amplified common-rail system (ACRS)
Lubrication System: Wet sump
Lubrication Capacity: 45 quarts (43 L)
Dry Weight: 2,837 pounds (1,287 kg)
Length: 63.7 inches
Width: 51.1 inches
Height: 52.4 inches

Sources

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