Turbocompounding spreads its wings to Mack

Turbocompounding, developed by Volvo Powertrain, is finding more applications within the group as Mack Trucks unveils its new product lineup for 2017.

Mack Trucks has revealed what it calls "the next step" in the evolution of its integrated powertrain by introducing its 2017 Mack MP series engines, bringing significant improvements in fuel efficiency, power and productivity, while reducing greenhouse gas emissions.

Thanks to several upgrades and enhancements, the new engines boost fuel efficiency from 2.1 to 8.8 percent compared with prior model year engines.

Mack’s 11-litre MP7 and 13-litre MP8 engines received a number of advancements for 2017, simplifying maintenance and improving efficiency and productivity.
The 2017 Mack MP8 will be available for order in April 2016, while the 2017 MP7 and MP10 engines will be available for order in July 2016. The Mack MP8 with turbo compounding will be available for order in October 2016.
Both engines feature an updated wave piston design that raises the compression ratio and enables more complete combustion of fuel, while a common-rail fuel system “more precisely injects fuel”. Combined with a two-speed coolant pump, these features help increase MP7 fuel efficiency by up to 5.1 per cent and MP8 fuel efficiency by up to 5 per cent. And the new MP8 is 20kg lighter than the outgoing design.

A number of additional improvements were made to both engines, including a new two-piece valve cover, shimless rockers and a low-pressure fuel system with an enhanced, integrated aftertreatment dosing module to reduce maintenance needs.

An updated, double-walled EGR flow sensor helps reduce condensation and soot buildup in cold weather, while a new intake throttle enables a faster warmup when the engine is started.

                              Weight-sensitive applications

“In addition to efficiency and maintenance improvements, we’re also delivering more power,” said Stu Russoli, Mack highway and powertrain products marketing manager. “With a new 425 bhp rating, the 2017 MP7 offers 13-liter power in a lightweight, efficient 11-liter package ideal for weight sensitive applications.”

For customers with long-haul applications, Mack will offer the 2017 MP8 engine with a turbo compounding system engineered to give customers a “no-compromise” increase in power and efficiency. Turbo compounding converts waste energy from the exhaust into mechanical energy that is fed back to the engine. The system adds up to 50 bhp (a figure claimed also by Volvo earlier this year), enabling a substantial increase of fuel efficiency of up to 8.8 percent.

The Mack MP8 with turbo compounding is available with Mack’s Super Econodyne down-speeding package. The additional power generated by the turbo compounding system allows the engine to maintain full torque as low as 900 rev/min. This not only enables a broader operating range in top gear, but also allows truckers to hold top gear longer when overtaking a hill, even with falling engine speed.

“With the current MP8, our Super Econodyne applications required a minimum top speed of around 63 miles per hour in order to stay in top gear,” explains Russoli. “Now, with turbo compounding, we can offer Super Econodyne and its fuel efficiency benefits to more customers.”

The 16-litre Mack MP10 engine, the most powerful Mack engine offered, carries over unchanged. With up to 605 bhp and 2,060 lbft torque, the MP10 comes standard in the Titan by Mack model, the ideal choice for heavy-haul, severe-duty applications.

Mack suggests that several of the revised components and technologies found on Mack’s 2017 MP series engines – including the patented wave piston, turbo compounding and the common rail fuel injection system – were derived from research and development work associated with the U.S. Department of Energy’s SuperTruck programme.

                          Cost-shared engine development

The SuperTruck programme, a cost-shared, public-private partnership, aims to help accelerate the research and development of advanced efficiency technologies to improve the freight-hauling efficiency of heavy-duty Class 8 long-haul tractor-trailer trucks. Mack also benefits from Volvo's powertrain expertise in Sweden and is thus a good example of present-day "badge engineering". As readers will be aware, both Scania and Volvo have exploited the benefits of turbocompounding.

Mack trucks built for the North American market are assembled at its Lehigh Valley Operations facility in Macungie, Pennsylvania. Volvo Trucks North America builds its trucks at a facility in Dublin, Virginia.
Mack-badged engines and transmissions for the North American market are built at its powertrain facility in Hagerstown, Maryland. Mack is part of the Volvo Group, one of the world’s leading manufacturers of trucks, buses, construction equipment, marine and industrial engines.

The plant in Hagerstown develops and manufactures all of the brand’s heavy-duty diesel engines, transmissions and drivelines.  Mack says that every powertrain built in Hagerstown meets and exceeds all federal and state legislation, including greenhouse gas certifications. Since 2001, Mack has invested more than $385 million to upgrade the 1.5 million square-foot plant, including the addition of a new engine development laboratory.

The address of Mack Powertrain North America is 3302 Pennsylvania Avenue, Hagerstown, Maryland. The address of Volvo Powertrain is 13302 Pennsylvania Avenue, Hagerstown, Maryland!