LONDON, U.K. --- Volvo Trucks is launching an upgrade of its hybrid refuse truck, Volvo Trucks Europe Division said. 

After a year and a half of initial field testing with positive results, an upgraded truck is now being released with new components and software. The new refuse truck will be tested by Veolia Environmental Services in central London. 

"Up to 30 percent lower fuel consumption, low emissions and a low noise level make this hybrid a very attractive choice. That's why we're keen to test and develop the technology in partnership with Volvo Trucks, with whom we have developed a very strong working relationship," said Rob Stubbs, fleet director at Veolia in London, a major waste management provider in the U.K. The company has ordered the new refuse truck. 

The new truck is an upgraded version of the trucks field-tested in Stockholm and Göteborg, Sweden, over the past 18 months. Like these trucks, the new refuse truck is what is known as a parallel hybrid. This means it has two separate drivelines, one for diesel and one for electricity, which can be used either separately or together. The benefit of this is that each fuel type can be used where it is most fuel-efficient -- the electric motor at low revs and the diesel engine at high revs. 

"The basic concept is the same, but all the components and software have been updated," said Fredrik Bohlin, business manager of hybrids at Volvo Trucks. "Development is extremely fast, and the technology in our latest test vehicle is much closer to a production-ready solution." 

The new refuse truck has electric power steering, completely new control systems and refined battery management strategies to optimize the battery performance. Loading and refuse compaction are completely electrically powered by means of a plug-in compactor that is charged via the main electricity grid. The battery is also new, with improved reliability and a longer lifespan, the company said. 

According to Fredrik Bohlin, a small-scale series production of the hybrids will start in 2012 at the earliest, which is somewhat later than the original plan. The delay is related to the global financial crisis that has affected both Volvo's product development and customers' investment capacity.

The field tests underway have given Volvo Trucks' engineers valuable experience, which will be used when developing the new refuse truck. Making two drivelines work together has proved to be a balancing act. 

"For example, if you want to minimize fuel consumption, you can maximize the use of the electrical power unit. However, this reduces battery life. So to achieve an optimal solution, many different properties must be weighed against each other," explained Fredrik Bohlin. "It's all about satisfying high demands for performance, lifespan, fuel consumption and operability." 

The initial results from all Volvo hybrid test vehicles show that the prediction of up to 30 percent less fuel and carbon dioxide emissions has been validated, Volvo Trucks said. Renova, a waste and recycling company in Göteborg, is among the customers that have been testing Volvo's hybrid refuse truck since spring 2008, and the client can report an even greater reduction. 

"The hybrid has met our expectations and our drivers are highly satisfied," said Lars Thulin, vehicle development manager at Renova. "The electrical power system provides high torque from start-up, low noise level and emission-free loading and refuse compaction. In terms of fuel consumption and climate impact, our measured results are even better than expected. We've achieved reductions of a staggering 35 percent."