Mercedes-Benz has unveiled the third generation of its OM 471 heavy-duty commercial vehicle diesel engine for Actros and Arocs trucks. The new version offers up to 4% better fuel economy and compliance with stricter emissions standards such as Euro 6e. The in-line six-cylinder will be manufactured at Mercedes’ plant in Mannheim, Germany.
"With the third generation of the OM 471, we consistently focused on the needs of our customers,” says Mercedes-Benz Trucks CEO Karin Rådström. “Our goal was to decrease the total cost of ownership (TCO) and reduce fuel consumption. Our customers will benefit, as will the environment."
Application-Specific Turbos
Mercedes developed a number of innovations for the next-gen OM 471. “All innovations that consistently aim at reducing the total cost of ownership in terms of fuel-saving driving, lower operating costs, and higher yields, without sacrificing performance, driving dynamics, or driving comfort,” says Daimler Truck’s Christoph Mertens, the project manager for the new engine.
The manufacturer increased the new OM 471’s compression ratio from 18.3:1 to 20.3:1 for more efficient combustion. Tweaks to the injection nozzle, the cylinder head, and the piston recess geometry yield a peak ignition pressure of 250 bar (25,000 kilopascals). A new exhaust aftertreatment system improves emissions reduction as well as fuel economy.
Mercedes also engineered two custom turbochargers optimised for top fuel efficiency and performance with the new OM 471 engine. The fuel-economy turbo will be paired with a motor with up to 350 kilowatts (476 horsepower) for long-distance haulage. The high-performance, high engine braking force turbocharger will boost a version of the OM 471 for heavy-duty and construction vehicles with up to 390 kW (530 HP).
A fair portion of an internal combustion engine’s energy is lost to friction, so Mercedes came up with ways to reduce its effects. A new engine oil pressure control valve intelligently reduces power-robbing oil pressure when all engine components are sufficiently cooled and lubricated. Also, a new, low-viscosity oil was also developed to facilitate pressure control while maintaining parts protection and the same oil change interval.
Drivetrain Improvements
Mercedes also developed new drivetrain features to enhance the driving dynamics of a truck with the OM 471 engine. The PowerShift Advanced automated transmission control speeds up gear shifts for up to 40% less torque interruption. It also increases and smooths out acceleration, including from a standing start. Moreover, the truck’s accelerator pedal will provide greater response as needed, such as for coming out of roundabouts, as well as more sensitive manoeuvrability at low speeds.
Finally, an extended Top Torque range provides “power at the press of a button” when more acceleration is required, such as on on-ramps and when overtaking other vehicles. It applies 200 newton-metres (147.5 pounds-foot) of torque to the crankshaft in gears 7 through 12. The new feature is available for 330- and 350-kW (450- and 476-HP) OM 471 engines with a G281 transmission.
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Source: Mercedes-Benz