VOLVO TRUCKS FIRST TO RUN DIESEL ENGINES ON GAS IN COMPLIANCE WITH EURO 5

Volvo Trucks will be the first manufacturer with an efficient diesel engine fuelled by a mixture of methane gas and diesel to meet the strict Euro-5 exhaust emission standards introduced in 2009. Field testing will start in Sweden and the UK in 2010.

“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,” comments Lars Mårtensson, Environmental Director Volvo Trucks. “As a result, this truck consumes about 30 per cent less energy than traditional gas trucks do.”

In August 2007, Volvo Trucks presented no less than seven driveable FM trucks adapted for use by different biofuels. Following further analysis, the company is now focusing on two renewable fuels - DME and methane gas + diesel.

“Methane gas is by far the most accessible fuel as an alternative to diesel. There are larger reserves of natural gas than oil. But above all, production of climate-neutral biogas is gaining momentum in many countries, which solves the most urgent problem – reducing CO2 emissions,” says Lars Mårtensson.

It used to be difficult to use methane gas for long-haul transportation. A truck with a spark-ignited engine usually has a restricted range of operation (approximately 150-200 kms). Volvo Trucks solves this problem by combining methane gas with diesel and using this fuel in a diesel engine. This increases the operational range by over 50 per cent. In addition, the diesel engine’s driveability is better compared to a spark-ignited engine.

How Volvo Trucks’ gas truck works
The solution is based on Volvo’s proven, reliable 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 pressurised 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,” explains Lars Mårtensson.

If the gas runs out, the truck can continue operating solely on diesel power. This is unique to Volvo's technology and makes this system a realistic option for many customers, especially in areas where the gas distribution network is underdeveloped.

Field testing to optimise technology
The amount of diesel required during operation varies, but Volvo Trucks aims to minimise the proportion of diesel.

“We expect to be able to run on up to 80-90 per cent methane gas once the technology has been refined and tested,” says Mats Franzén, Manager Engine Strategy and Planning, Volvo Trucks. “Our field tests in 2010 will start with a mixture containing up to 70 per cent methane gas. The remainder will consist of bio-mix diesel, i.e. fossil diesel mixed with diesel produced from renewable raw materials.”

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

Strong interest from the market
There are two main factors driving the increased market demand for gas-powered trucks. 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. To optimise and refine the technology, Volvo Trucks is also collaborating with technology companies Clean Air Power, Hardstaff Group and Westport.