Mercedes-Benz Actros: economical and environmentally compatible

Benefit for companies: outstanding economy.

Never before has a long-distance truck been as systematically designed for maximum efficiency as the Mercedes-Benz Actros. It stands for the ultimate in economy in the tough transport business. With the introduction of the second generation OM 471 heavy-duty engine, the already low fuel consumption is further reduced by up to three percent.

This is thanks to sophisticated engine technology such as the second generation of the unique X-Pulse injection system, a patented solution for exhaust gas recirculation and simultaneous control of the exhaust gas turbocharger, a highly precise turbocharger developed and produced in house, plus a wealth of other measures including a longer axle ratio.

Economy also means maximum robustness: several components can be omitted because the engine is systematically pilot-actuated. The motto for this is as simple as it is logical: if it's not installed, it can't wear out. In this way the outstanding reliability of the OM 471 is further enhanced.

Benefit for drivers: further enhanced dynamism.

For the driver of the Actros with the second generation OM 471, lower fuel consumption nevertheless means greater driving dynamics. A fast and steep increase in output ensures powerful starting and acceleration, even from the bottom of the rev range. Even from idle speed, the engines pull powerfully and almost reach their peak torque before the rev counter even hits 1000 rpm. Some 95 percent of the maximum torque is then available between around 1300 and 1400 rpm, and the rated speed is now 1600 rpm.

Despite nominally identical maximum output and torque data, the engines operate far more powerfully in the most frequently used engine speed range between 1000 and 1500 rpm. On the road this translates into outstanding drivability under all conceivable conditions across an extremely wide engine speed range of around 1000 rpm.

Benefit for society: maximum environmental compatibility.

In the case of heavy-duty commercial vehicles, maximum efficiency is automatically linked to the best possible environmental compatibility. The low fuel consumption achieved by the Mercedes-Benz Actros is not only good for the company's bank balance, it also preserves resources: assuming a typical mileage of 130.000 km per year, predominantly demanding routes and full capacity utilisation, the Actros with the second generation OM 471 saves around 1100 litres of fuel per year compared to its predecessor. This is equivalent to a reduction in CO₂ emissions of around three tonnes for every single truck.

Extremely long maintenance intervals for engine oil service and cleaning of the particulate filter likewise help to protect the environment. The emissions of the Actros with Euro VI emissions standard are already at the limit of detection.

Up to three percent lower fuel consumption proven in precise tests.

The Mercedes-Benz test engineers have proven the outstanding economy of the Mercedes-Benz Actros with the second generation OM 471 in tough tests – rather than being theoretical, its lower fuel consumption is proven in practice.

Standard test routes include the motorway link from Stuttgart to Hamburg and back, which has been used by the testing department for around two decades. The 1520 km stretch is not only one of the most important main routes in Central Europe, it also offers a varied route profile: a mix of hilly stages, demanding mountain sections and flat stretches.

Daimler Trucks does not just compare its own trucks with each other, competitor models also take part in the tests. Thorough preparation is vital when it comes to making objective measurements. The trucks must be directly comparable in terms of engine power and torque, transmission, axle ratio, and control systems such as Predictive Powertrain Control (PPC). The cabs and the trailers, including the load and tyres, are likewise standardised. Further prerequisites for an in-house comparison test include painstaking checking of all components on an output dynamometer, wind-tunnel measurements for correctly installed and adjusted aerodynamic attachments plus calibration of the speedometer and fuel measuring system.

The vehicles are always driven under the same conditions as the reference vehicle, with as few driver interventions as possible. Additional test requirements include stable general conditions such as avoidance of heavy traffic and environmental influences such as strong winds or rain. Changing drivers and swapping trailers evens out any external influences.

Despite everything and even with the most painstaking of preparations, the fuel consumption differs by up to three percent per tour due to various influences such as the weather or traffic. These differences are evened out by performing several test drives in succession and conducting a detailed assessment.

Meticulous preparation for comparative tests.

Certain values show how important maximum neutrality is in comparative tests. A truck's fuel consumption falls by about two percent during its running-in phase from around 80.000 km. Tyre type and brand can influence fuel consumption by around five percent. Different tread depths can have the same effect. The difference between summer and winter diesel likewise affects fuel consumption by around five percent. Last but not least, having one tonne less weight on a 40 t articulated truck used for long-distance transport reduces fuel consumption by around 1.5 percent.

As well as being checked by incorruptible measuring equipment, the fuel consumption is also determined by precise refuelling. Important factors here include an always constant position at the identical fuel pump, precise refuelling up to a specified mark and measurement of the fuel temperature. Even a difference in fuel temperature of around ten degrees makes a difference of about one percent due to the different expansion of the fuel. In a tank holding 500 litres, this means a difference of five litres.

The test engineers have taken all these parameters and many others into account. The result is clear: on the road, the Mercedes-Benz Actros with the second generation OM 471 really does consume around three percent less fuel. And it has verifiably lower fuel consumption than its competitors. The Actros truly does represent maximum efficiency among the long-distance trucks in its class.

Four years on from the debut of the Mercedes-Benz OM 471 heavy-duty engine, the next evolution is here – and will allow the Mercedes-Benz Actros from Daimler Trucks to consolidate its lead in the efficiency stakes. Fuel consumption is reduced again by up to three percent whilst driving dynamics are enhanced. The series is spearheaded by a unit offering new top performance figures of 390 kW (530 hp) and 2600 Nm of torque. Last but not least, the engines are more robust than ever. In short, the second generation OM 471 once again sets the standards for heavy-duty engines.

OM 471 in-line six-cylinder engine: a new era in engine manufacturing.

A perfect blend of economy and ecology: in spring of 2011, Mercedes-Benz presented an all-new engine generation in anticipation of the Euro VI emission standard. The first member of the new engine family was the OM 471.

With its technical features and the resulting capabilities and qualities, the heavy-duty engine took engine manufacturing for heavy-duty commercial vehicles into a brand new era. The 12.8-litre in-line six-cylinder unit made its mark with a robust design and technical innovations with significant benefits for the customer. Key features included two overhead composite camshafts, the unique common-rail injection system with X-Pulse pressure booster, the asymmetric exhaust gas turbocharger, the powerful engine brake and emission control with SCR technology, exhaust gas recirculation and particulate filter to meet the requirements of the strict Euro VI emissions standard.

Four years on, the engine developers have further greatly enhanced the excellent characteristics of the OM 471. The main aim: engines that are systematically designed to ensure low running costs.

New: five output ratings up to 390 kW (530 hp).

The Mercedes-Benz OM 471 is available in five basic versions:

Output	Torque
310 kW (421 hp) at 1600 rpm	2100 Nm at 1100 rpm
330 kW (449 hp) at 1600 rpm	2200 Nm at 1100 rpm
350 kW (476 hp) at 1600 rpm	2300 Nm at 1100 rpm
375 kW (510 hp) at 1600 rpm	2500 Nm at 1100 rpm
390 kW (530 hp) at 1600 rpm	2600 Nm at 1100 rpm

The variants delivering 310, 330 and 350 kW are complemented by three “top torque” versions. With these engines, an extra 200 Nm of torque is placed on tap as required whenever the highest gear of the Mercedes PowerShift 3 automated transmission is engaged. This reduces the shift frequency and, in combination with a longer rear axle ratio, increases the transport speed without increasing fuel consumption.

New: the second generation of the X-Pulse injection system.

A key component of the second generation of engines is the second generation
X-Pulse injection system – the unique common-rail system with pressure booster in the injector and unrestricted flexibility for modelling the injection system. Maximum rail pressure has been increased from 900 to 1160 bar, resulting in a maximum injection pressure of 2700 bar.

The injection nozzle is an eight-hole injector. Also new is the geometry of the piston bowl, a compression ratio increased from 17.3:1 to 18.3:1 and the reduced exhaust gas recirculation rate (EGR rate). All of this together adds up to a further improvement in efficiency across the entire range of the engine mapping. This in turn lowers fuel consumption significantly. Corresponding to the new torque curve, the best figures on the consumption map shift to lower engine speeds.

Systematically configuring the engine for low fuel consumption means that untreated NO_x emissions rise in return. This is countered by SCR technology featuring an innovative and efficient SCR catalytic converter. AdBlue consumption is therefore on a par with earlier Euro V engines at around five percent of fuel consumption.

The costs work out: the drop in fuel consumption of up to three percent comes at the expense of nothing more than a slightly higher quantity of the far cheaper AdBlue needed for emission control. Assuming an annual mileage of 130.000 km in long-distance transport and a consumption of approx. 28.5 l/100 km on a demanding route covered at full load capacity, every single Mercedes-Benz Actros with the second generation OM 471 engine would save around 1100 litres of fuel a year and emit about three tonnes less CO₂.

New: top-of-the-range engine with 390 kW (530 hp).

The second generation X-Pulse system with its far higher injection pressure is also a vital prerequisite for the new top-of-the-range version of the OM 471 engine. It generates an output of 390 kW (530 hp) while delivering an outstanding peak torque of 2600 Nm. Even just above its idle speed, the new engine produces a mighty 1600 Nm of torque. Special mention should be made of both the specific output of 30.5 kW (41.4 hp) per litre of displacement and the torque of 203 Nm per litre of displacement.

New: high torque even from the bottom of the rev range.

All of the OM 471 output variants benefit from the new injection system. Although the maximum output and peak torque figures remain nominally unchanged, the output and torque curves in the lowest rev range rise far more sharply, endowing the engines with quite different performance characteristics. The engines already muster up at least 2000 Nm of torque at just under 800 rpm. Depending on the output rating, close to peak torque is now already on tap between around 800 and 950 rpm.

The output curves of the new engines look just as favourable. Depending on the output variant, 95 percent of maximum output is already being generated at around 1300 to 1400 rpm. The rated speed is now 1600 rpm, yet even at the previous speed of 1800 rpm, output is just one percent below maximum.

What this means in practice is outstanding drivability under all conceivable conditions across an extremely wide usable engine speed range of about 1000 rpm. At low revs in particular, the already powerful engines now rank at least one output category higher than previously.

Mercedes-Benz uses these characteristics for a longer standard ratio on the rear axle. The ratio of i=2.533 reduces the engine speed level by three percent. With 315/70 R 22.5 tyres, this results in a speed of around just 1150 rpm at a speed of 85 km/h. At the same time, the engines have far higher reserves when driving uphill.

New: patented solution for exhaust gas recirculation.

The asymmetric turbocharger has been one of the special features of the OM 471 engine from the very start. To ensure fast build-up of the charge pressure, the exhaust gases from cylinders four to six are forwarded directly into the turbine without detour. A defined quantity of the exhaust gases from cylinders one to three, on the other hand, is used for exhaust gas recirculation to reduce NO_x emissions.

This solution has been decisively enhanced. One new feature is an EGR flap moved a long way forward in the exhaust manifold, which allows infinitely adjustable and very precise control of the exhaust gas distribution between exhaust manifold and turbocharger across the entire range of the engine map. This results in effective thermal management and a lower EGR rate in general with advantages for fuel consumption.

Both the EGR rate and the exhaust gas flow to the turbocharger can now be controlled in accordance with the engine operating characteristics. The repositioning of the EGR flap furthermore opens up a whole new spectrum of asymmetry: the quantity of exhaust gases directed from the three donor cylinders to the combustion process can be varied exactly as required between zero and 100 percent – something which is unprecedented in engine manufacturing and therefore patented.

New: asymmetric injection optimises emissions quality.

The asymmetric injection is another new feature. During normal driving, the injectors for all six cylinders in the OM 471 engine are supplied with an identical quantity of fuel. If regeneration of the diesel particulate filter is required at low loads, a high EGR rate of up to around 50 percent is set in order to raise the exhaust temperature.

In order to prevent incomplete combustion in this situation, which would result in a higher proportion of soot particles in the exhaust gas, the fuel quantity is smoothly reduced in cylinders one to three as the EGR rate rises and increased in cylinders four to six. In extreme cases, the injection quantity for the first three cylinders can be zeroed, while the other three cylinders operate as if at full throttle. Consequently, the exhaust gas quality increases while particulate emissions are reduced.

New: supremely efficient turbocharger manufactured in-house.

A new asymmetric turbocharger is partly responsible for the swift and substantial increase in power delivery. It was developed by Mercedes-Benz and is manufactured at the Mannheim engine plant. An in-house turbocharger ensures customised adaptation to the requirements of the OM 471. The turbocharger impresses with its outstanding efficiency. Very tight production tolerances are a guarantee for supreme quality and durability.

As before, the asymmetric turbocharger features a fixed turbine geometry. From a technical standpoint, this variant is far less complex and thereby less prone to fail than a turbocharger with variable turbine geometry, for instance. It also does without a wastegate valve, further simplifying the design.

New: even more robust thanks to the omission of sensors and pilot-actuated operation.

Mercedes-Benz has also dispensed with boost pressure control, the EGR sensor and EGR control in the second generation of the OM 471. The thermodynamically thoroughly optimised engine is always operated in pilot-actuated mode and is therefore even more efficient. At the same time, the engine has become even more robust owing to the omission of numerous components and parts.

Fuel consumption cut by up to 13 percent in just four years.

The advances are remarkable: since 2011, following the introduction of the new Actros with Euro VI emissions rating, the Predictive Powertrain Control (PPC) cruise control system and the new engine generation, average consumption has dropped by up to 13 percent compared to the predecessor Actros model. By contrast, long-term improvements in consumption normally average out at around 1.0 to 1.5 percent per year in the commercial vehicle sector, which further underlines the expertise and innovative strength of Mercedes-Benz.

The second generation of engines combine supreme economy on the one hand with extraordinary performance capabilities on the other. It is a further high point in a fascinating development.

It is systematically designed for low operating costs like no other truck: as a result of an unrivalled complete package of technology and service, the Mercedes-Benz Actros sets standards with its outstanding efficiency. One instance where the Actros has proven its unparalleled economy is in the Fuel Duel - a fuel consumption comparison test in more than 1500 fleets all over Europe. The Fuel Duel is now entering its next round with the second generation of Mercedes-Benz OM 471 engines in the Actros.

Fuel Duel: The Actros never shies away from
a consumption contest.

In the Fuel Duel the Actros lines up against the best trucks in each fleet for the fuel consumption test. In just short of three years, it has now entered more than 1500 consumption contests, clocking up around 7.5 million kilometres in the process. The results are impressive: the Actros has won more than 90 percent of these duels. On average it consumes over ten percent less fuel than its competitors.

This is how the Fuel Duel works: the Mercedes-Benz Actros takes on the jobs of a competitor vehicle in a fleet and handles its loads and routes for two weeks. The driver receives detailed instruction in advance and, at the beginning, is accompanied by an expert. He then carries out his customary work with the Actros alone, supported by the Fleetboard telematics service.

This fuel consumption comparison test takes place in 22 countries, from Finland to Italy, from Spain to Romania. 90 Actros trucks are used, predominantly 1842 LS and 1845 LS tractor units. Anybody who wishes can follow the contest on the internet: the website www.fuelduel.com continuously updates the overall standings and the results in the individual countries in the language of those countries.

Now the Fuel Duel is entering its next round: Mercedes-Benz is this year providing the Actros with the second generation of OM 471 engines as a test vehicle for customer fleets.

The fuel consumption factor: 30 percent of overall costs.

The economy of the Mercedes-Benz Actros and its cost advantages are backed up by hard facts. Fuel consumption accounts for about 30 percent of the Total Cost of Ownership (TCO), i.e. the total cost over the entire time a long-distance truck is owned. Maintenance and repairs account for a further ten percent of the TCO.

A vehicle manufacturer can have a direct influence on this 40 percent of the TCO. Other factors such as personnel costs (around a quarter of overall costs) plus fleet management, road tolls, road tax and insurance – together likewise around a quarter of overall costs – are outside of the manufacturer's scope of influence. Compared to these blocks of costs, the procurement costs for a truck are relatively secondary as they only account for about ten percent of the TCO.

A simple calculation example highlights the pivotal significance of the costs for fuel, maintenance and repairs in the overall reckoning: ten percent lower fuel costs increase a transport company's profit margin by three percent, ten percent lower maintenance and repair costs increase it by a further percentage point. This calculation also works the opposite way round: trucks with unnecessarily high costs for fuel, maintenance and repair ruin a transport company's profit margin.

Outstanding aerodynamics and economical auxiliary consumers.

Alongside safety, ease of use and comfort for the driver, the Mercedes-Benz Actros therefore focuses on economy. Its cab has spent 2600 hours being optimised in the wind tunnel, for instance. The result is an aerodynamically optimised basic body, immediately obvious on the StreamSpace cab especially. Visible evidence of the aerodynamic detailing includes the attachments on the cab from the front spoiler to the side flaps, low-edged door sections and a radiator shutter that opens or closes depending on the engine's cooling requirements. Even if it may seem a little unusual at first, the positioning of the air horn behind the trim alone reduces fuel consumption by 0.2 percent.

Like the engine, transmission and drive axle, the auxiliary consumers in the Actros are honed for maximum efficiency, one example of this being the two-stage air compressor, which is preferably operated in deceleration mode. Or the E-APU air control system with high reservoir pressure in the lines and air pressure production during braking. The list goes on. As a result, the amount of fuel consumed by the Actros Euro VI newly introduced in 2011 was up to five percent lower than that of its already economical predecessor.

Predictive Powertrain Control reduces consumption
by up to five percent.

The list of consumption-reducing measures has been growing continuously ever since. Another milestone was reached in autumn 2012 with the introduction of Predictive Powertrain Control (PPC). PPC links GPS information with three-dimensional map data. Together with the now perfectly used EcoRoll gliding function, this results in a driving style precisely adapted to the topography.

With PPC on board, the Actros accelerates, rolls and changes gear like a foresighted driver with excellent knowledge of the route. However, the technology suffers from neither lapses in fitness nor drowsiness and is familiar with almost all of the motorways and main roads in Europe. The result is yet another reduction in fuel consumption of up to five percent.

Overall economy beyond the powertrain.

Fuel consumption can be reduced by a further three percent thanks to the second generation Mercedes-Benz OM 471 engine, which is systematically designed for maximum efficiency like no other truck engine currently on the market.

Mercedes-Benz always looks at the whole picture when it comes to economy, however, and goes way beyond sophisticated fuel-saving technology. Because, when it comes to the tough transport business, one perceived truism is undeniable: a truck can only earn money when it's on the move. The second generation OM 471 is therefore even more robust than its famously reliable predecessor engines thanks to its purely pilot-actuated operation and the omission of certain components.

Furthermore, the Actros achieves extremely long maintenance intervals of up to 150,000 km. Its particulate filter does not need to be cleaned until reaching 450,000 km and subsequently every 300,000 km. The maintenance-friendly arrangement of the components minimises service downtime.

Unique network of services ensures high economy.

Apart from this, every Mercedes-Benz Actros can call upon a unique network of services. Starting with tailored financing concepts and also including sensible warranty and service packages as well as Europe's most extensive workshop network with customer-friendly opening hours. The FleetBoard telematics system supports companies with extensive and practical services, the MercedesServiceCard* allows straightforward transactions on the road, and Service 24h is available Europe-wide around the clock and 365 days a year should the worst come to the worst.

All in all the Mercedes-Benz Actros ensures pure economy for the operator – right up until its sale at TruckStore, Europe's number one for used trucks.

* MercedesServiceCard is not applicable to the UK market