In August 2007, Volvo Trucks presented no less than seven driveable demo trucks adapted for 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 km). 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 percent, but when a liquefied gas is used, with higher energy density, the range will double. 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 diesel 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 on only diesel. This is unique to Volvo's technology and makes this system a realistic option for many customers, even 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 percent 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 percent 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 percent in the long term compared to traditional diesel operation, if biogas and 100 percent 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.
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.
Volvo Trucks’ technology for methane gas + diesel – summary of strengths:
- Volvo Trucks is the first manufacturer to run efficient diesel engines on gas in compliance with Euro 5.
- Approximately 25 percent lower energy consumption compared to traditional gas operation.
- Same power and driveability as conventional diesel trucks.
- Using two fuels makes it possible to continue the journey using only diesel if the gas runs out – a useful feature until the gas distribution network is fully developed.
- The engine’s high efficiency rating, combined with the option of using liquid gas tanks, makes the technology a realistic option for long-haul operations.
Facts about methane gas:
Both natural gas and biogas consist of methane. The difference is that natural gas is a fossil fuel, whereas biogas is produced from biodegradable material such as waste.
December 15, 2009
For further information, please contact:
Lennart Pilskog, Corporate Communications,, tel +4631 664926, e-mail lennart.pilskog@volvo.com
Per Nilsson, Media Relations Europe, phone +46 31 323 3349, e-mail per.nilsson.pr@volvo.com
