Calculated over the whole fuel chain, from production to use on roads, the new technology could reduce carbon dioxide emissions by up to 80% in the long term compared to traditional diesel operation, if biogas and 100% biodiesel are used, Volvo says.

This unique technology allows us to combine the advantages of gas with the diesel engine’s high efficiency rating, which is about 50 per cent superior to that of the spark plug engine. As a result, this truck consumes about 30 per cent less energy than traditional gas trucks do.

—Lars Mårtensson, Environmental Director Volvo Trucks

In August 2007, Volvo Trucks presented seven driveable FM trucks adapted for use by different biofuels. (Earlier post.) Following further analysis, the company is now focusing on two renewable fuels: DME and methane gas + diesel (biomethane plus biodiesel).

The solution is based on Volvo’s proven Euro-5 diesel engines. When the engines are converted for gas operation, special tanks are added for either liquid volume-efficient methane gas (LNG/LBG) or pressurized methane gas (CNG/CBG). In addition, a separate fuel system is added with gas injectors in the inlet manifold.

A small amount of diesel is injected and ignited by the compression, which in turn ignites the methane gas/air mixture. This saves the need for a spark plug and allows Volvo to make full use of the efficient diesel technology. As a result, the power and driveability are identical to that of a conventional truck.

Processors continuously calculate fuel ratio according to the driver’s current driving pattern. The optimum—i.e. the highest—proportion of gas is achieved during smooth, stable driving.

—Lars Mårtensson

If the gas runs out, the truck can continue operating solely on diesel power. This feature of Volvo’s technology makes this system a realistic option for many customers, especially in areas where the gas distribution network is underdeveloped. To optimize and refine the technology, Volvo Trucks is also collaborating with technology companies Clean Air Power, Hardstaff Group and Westport.

There are two main factors driving the increased market demand for gas-powered trucks, Volvo says. One is cost savings. Methane gas is currently a relatively cheap fuel in many markets. For example, Volvo Trucks’ technology already offers a profitable fuel option for trucks undertaking long daily transport jobs and returning to the same filling station (i.e. municipal or local haulage operations)

The other driving factor stems from the strict environmental regulations in many towns and cities, playing a crucial role in purchasing decisions, particularly in municipal companies. Volvo Trucks maintains a dialogue with several fuel companies to ensure that filling stations are constructed to keep pace with the increasing number of vehicles out on the roads. This will prepare the ground for broad market introduction in the future, the company says.