That is why Mercedes-Benz Trucks is doing everything it can to make its diesel engines as efficient and ecofriendly as possible

The workshop defines the principal leverage points for the future and works out what measures will give customers what benefits.

• Over the medium term, long-distance haulage in particular will continue to depend on trucks with combustion engines
• For the customers, a reduction in fuel consumption is one of the most effective ways of reducing the overall cost of their trucks
• Realistic simulations identify the potential for further optimising fuel efficiency at Mercedes-Benz Trucks
• Fuel consumption and CO₂ emissions are linear variables: the more stringent emissions limits of the future can only be adhered to by reducing consumption
• The variety of configurations and application areas makes exact fuel consumption calculations for trucks a complex matter – the engineers at Mercedes-Benz Trucks have been leaders in this field for 30 years 

The same thing applies to large truck fleets as to smaller hauliers: when it comes to fuel consumption, even the slightest potential savings can have a huge impact on overall truck running costs. A sample calculation: let's assume that a new long-distance-haulage truck receives aerodynamic and powertrain improvements that reduce diesel consumption by three percent. With an annual mileage of 120 000 km, a diesel price of €1.20 per litre and an average fuel consumption of about 30 litres per 100 kilometres for the old truck, this equates to a saving of around €1290 per year for the operator. The projected total for a fleet of 100 tractor units would therefore be a six-figure sum, allowing an additional vehicle to be purchased. Reducing fuel consumption is and will remain essential for the transport operators to ensure the profitability of their business. But fuel consumption is also always linked to the environment.

Exact calculations provide the basis for further optimisations

Fuel consumption and CO₂ emissions are linear variables and therefore linked to each other. Therefore, lower fuel consumption automatically means lower emissions. With respect to the increasingly stringent emissions standards in particular, improvements in fuel efficiency therefore play a key role. "The only way to detect and tap into potential for optimising fuel consumption and CO₂ emissions is through exact calculations and absolutely realistic simulations," says Wolfgang Sülzer, who performs consumption simulations and efficiency calculations for the group's entire model range at Daimler together with his team. "Our simulation results therefore make an important contribution in the development of even more efficient vehicles."

The optimisation of fuel efficiency in trucks poses stiff challenges for the developers: exact calculations are an extremely complex undertaking due to the variety of possible configurations and application areas. In contrast to passenger cars, trucks have a huge range of variable components such as different engines, transmissions or axles. Furthermore, the body, design and number of trailers as well as the truck's application have a major impact on the consumption. For a realistic simulation, it is also necessary to take account of exact environmental data and different driver types. Wolfgang Sülzer: "We do this work so that we can continue providing Mercedes-Benz Trucks customers with trucks that earn money due to their low fuel consumption and also meet the increasingly stringent regulatory requirements."

Computer simulations – as realistic as possible

A team from Daimler developed the first simulation software for calculating fuel and energy consumption as well as CO₂ emissions more than 30 years ago. And the basic principle back then has not changed to this day: the vehicle model drives in a simulated environment on a route with exactly the same operating profile that a certain customer group needs. The Daimler engineers have continually enhanced the software's performance over the years. New and increasingly complex parameters have been taken into account to make the calculations ever more exact. The current version of the software can even simulate the behaviour of individual control units in the truck. This replication of the electronic network in the truck provides much important impetus for improving the fuel efficiency of the entire system.

Simulations complement on-road tests

By analysing the fuel consumption and CO₂ emissions figures determined by simulation, the developers can identify further optimisation potential; tests under real conditions are still necessary alongside the simulations, however. Besides the simulations, consumption is also measured in road tests. The two disciplines complement each other rather than competing with each other. The tests and involve comparisons between competitor vehicles and in-house vehicles under the same general conditions, for example, i.e. with the same operating profiles and the same routes. It would not be possible to simulate these comparisons fully because Daimler does not have access to all the data of competitor vehicles. However, simulation does result in the calculation of many measures and, consequently, a reduction in costs.

The current Actros model alone has clocked up more than 20 million test kilometres on "real" roads – supplemented by extensive tests in material laboratories and on dynamometers. For the market launch in the growth regions of the Middle East and Africa, Mercedes-Benz Trucks asked its truck to complete a further six million test kilometres under the toughest of conditions in the United Arab Emirates – both on-road and off-road, in high humidity and extreme temperatures of up to 50 degrees Celsius or more, and with extremely heavy loads. The data gathered here then flow into the models, which Wolfgang Sülzer and his colleagues use to further develop their computer simulations.