Daimler drives for efficiency
DAIMLER TRUCK HAS ANNOUNCED a third generation update of the OM 471 heavyduty engine for the Mercedes-benz truck line-up.
Customers in Europe can already order the upgraded engine in both Actros and Arocs model lines with availability from October 2022.
Manufactured at the Mercedes-benz Mannheim plant, the updated OM 471 features a range of innovations to decrease the Total Cost of Ownership and reduce fuel consumption without sacrificing performance, driving dynamics or driving comfort.
The efficiency gains are the result of a number of engine innovations. For example, the geometry of the piston recess, the injection nozzle design and the parameters of the cylinder head relevant for gas exchange were subject to an extensive optimisation process.
The compression ratio of the six-cylinder inline engine has also been raised from 18.3:1 to 20.3:1, providing more efficient combustion with a peak ignition pressure of 250-bar.
Daimler Truck says one of the most important levers in increasing fuel efficiency in modern diesel engines is turbocharging optimisation.
The third generation OM 471 introduces two new turbochargers developed and manufactured in-house. The consumption-optimised variant, with the focus on the lowest possible fuel consumption, is used in engines rated up to 350kw (476hp). The second turbocharger variant is designed for high performance and a high engine braking force for engines rated up to 390kw (530hp).
It’s estimated the lower and medium performance levels of the OM 471 achieve a fuel saving compared with the previous generation of up to 4%. For the upper performance levels the saving is up to 3.5%.
Friction reduction is the third important lever for improving fuel efficiency and the genthree OM 471 has a newly developed engine oil pressure control valve - installed behind the engine oil pump and in front of the oil thermostat.
Available reductions in engine oil pressure are determined in a complex matrix that takes into account all engine components and their specific requirements, such as lubrication or cooling. A newly-developed engine oil with low viscosity enhances oil pressure control and improves fuel efficiency without reducing oil change intervals or increasing the wear on engine components.
The exhaust gas aftertreatment system has also been adapted to the new combustion and control system.
The system limits the counterpressure and also increases the uniformity index of the Adblue, which leads to improved NOX conversion and lower fuel consumption. The NOX sensors together with the closed and adaptive NOX closed-loop control circuit and a predictive SCR temperature model have enabled emission stability to be improved even further.
The engine complies with Euro VI-E, which calls for effective limitation of exhaust gas emissions over the entire normal service life of a vehicle under normal usage conditions.
The driving dynamics of the third generation of the OM 471 are enhanced by the new Powershift Advanced automated transmission control which enables smoother moving off and acceleration thanks to precise gear selection. Faster gear changes reduce the torque interruption time by up to 40% in the upper range.
T&D