Automotive Intelligence - the web for automotive professionals and car enthusiasts
November 14, 2007
“The Shaping Future Transportation initiative demonstrates that we take our responsibility toward customers and the environment very seriously. The initiative encompasses all of the globally networked research and development activities in the area of alternative drives and fuels for all of the brands at Daimler Trucks and Daimler Buses. The Shaping Future Transportation initiative also demonstrates that the environmentally friendly commercial vehicles from Daimler are no longer prototypes, but real vehicles that are being used by customers.”
Daimler plans to employ alternative drive systems in additional vehicle models and regions, focusing primarily on hybrids. In North America, Freightliner will manufacture 1,500 M2 hybrid trucks over the next three years and also produce a hybrid version of a Thomas Built school bus. In the meantime, the second-generation Mitsubishi Fuso Aero Star Eco Hybrid will be launched on the market in Japan. In Europe, the first Mercedes-Benz Atego BlueTec Hybrids will be delivered to customers in Germany, France, and the CzechRepublicnext year. At the same time, customers in the UKwill be conducting a pilot project with ten Mitsubishi Fuso Canter Eco Hybrids. For public transportation needs, Daimler unveiled a three-axle articulated Mercedes-Benz bus with the designation Citaro G BlueTec Hybrid, which will go into series production in 2009.
Because of their decreased fuel consumption, trucks and buses equipped with hybrid drives also produce fewer pollutants and less CO2. Daimler is also investigating the possibility of using alternative fuels in order to preserve fossil sources of energy. According to the commercial vehicle experts at Daimler, the most promising fuels from renewable resources are vegetable oil-derived hydrated fuels (HVOs). Later, they will be joined by BTL (biomass to liquid) fuels. In cooperation with the oil company OMV and the vehicle fleets of two of its customers (DHL and SSB-Stuttgart), Daimler has now commenced fleet testing of HVO fuel in Mercedes-Benz trucks and buses.
Biodiesel (FAME) has been commonly used in Mercedes-Benz trucks for the past ten years. And Mercedes-Benz has been producing and delivering buses and municipal vehicles that run on compressed natural gas (CNG) for almost just as long.
Daimler’s diesel engines have evolved into high-tech drive systems. As such, they will remain the chief means of commercial vehicle propulsion for many years to come. Diesel engines still have great potential, as evidenced by their minimized emissions and continuously increasing energy efficiency. As a result, emissions of particulates and nitrogen oxides have decreased by more than 90% on average since 1990. Mercedes-Benz trucks and buses equipped with BlueTec diesel technology combine environmental improvements with economic benefits for the vehicle operator. That’s because BlueTec technology has led to further substantial reductions in fuel consumption. In the case of long-haul trucks, for example, the annual reduction amounts to around 2,000 liters of fuel or more than five tons of CO2 emissions. “We often talk of the 'three-liter car,'" said Renschler (a vehicle capable of covering 100 kilometers on around 3 liters of fuel. “However in comparison, Daimler already has the 'one-liter commercial vehicle,' if you take the high transport volumes into account.”
Hybrid technology represents a further milestone in the reduction of fuel consumption on the path toward achieving economically viable zero-emission fuel cell drives. Hybrid vehicles incorporate two different types of drive system: an electric motor and an internal combustion engine. The energy released during braking is recovered as electric power, which is stored in batteries until it is used again to propel the vehicle via an electric motor. Thanks to this additional drive system, diesel engines can be made smaller and lighter without reducing driving performance.
Daimler has decided to use parallel hybrids for its trucks. In parallel systems, the electric motor is incorporated into the powertrain, where it generally works in parallel with the diesel engine to propel the vehicle. Due to the way they are used, Daimler’s hybrid buses are equipped with a serial hybrid drive. In this arrangement, a generator directly connected to the diesel engine provides the energy for the electric motors. In addition, all of the auxiliary systems of the Mitsubishi Fuso and Mercedes-Benz hybrid buses are electrically powered, which makes completely electrical and emission-free driving possible for short stretches. The technological transition to the zero-emission vehicle is being ushered in by the Mercedes-Benz Citaro G BlueTec Hybrid, which employs an innovative drive concept featuring wheel-hub motors. In principle, future generations of the vehicle will only need to replace the diesel-engine generator with fuel cells, as the electric drive components have already been tried and tested.
Fuel cell vehicles have already proved their suitability for day-to-day operations in the world’s largest field test, which involved 30 Mercedes-Benz Citaro buses. The vehicles were driven more than two million kilometers in over 125,000 hours of operation. However, the fuel cells’ service life needs to be substantially lengthened and their cost drastically reduced before they can be used in series-produced commercial vehicles. These goals will remain a challenge for the development engineers for some time to come. Another difficulty is that the necessary hydrogen infrastructure still needs to be created.
Because hybrid vehicles cost one-third more than today’s diesel vehicles, economic aspects will play a crucial role in the acceptance of alternative drive systems by operators. Although the overall cost of ownership of hybrid vehicles is substantially improved by their fuel savings, incentives will be needed for at least a few years following the market launch. This is confirmed by the success of alternative drive systems in the U.S.and Japanthanks to government incentives. Fleet operators in Europedo not yet have such inducements to purchase a hybrid vehicle. "Environmental protection will only be effective in the long term, if it also provides customers with economic benefits,” said Renschler.
(Nov 12, 2007)