With the new gas-powered engine, the challenge for Volvo Trucks engineers was to develop a new driveline that could reduce CO2 emissions immediately, offer customers the same high performance as diesel and be a viable solution for the future. The final solution meant re-thinking the whole usage of the diesel principle.
Volvo Trucks have realised the need for alternative fuels due to the growing concern over global warming, increasing the pressure to move away from fossil fuels. Many cities in the world are already moving to adopt new ways of reducing emissions with some looking to ban diesel powered cars from their cities altogether, in as little as a few years.
The question is: what will be the alternative? Which fuel source can reduce CO2 emissions, deliver the required power and performance and still be a commercially viable option for the average transportation company? Volvo Trucks believes that the answer – at least partly – is gas.
Volvo claim that the Volvo FH LNG and Volvo FM LNG are the first gas-powered heavy-duty trucks on the market that can offer enough power to meet the needs of heavy regional and long haul operations. Both models, which are available with 420 hp and 460 hp, offer the same performance and driveability as their diesel equivalent and can drive up to 1000km before having to stop and refuel.
In fact, the only difference is the fuel – liquefied natural gas (LNG) – which cuts both fuel costs and CO2 emissions significantly. When powered by natural gas – which in the short-term is a more viable option for most transport operators – CO2 is reduced by 20 per cent compared to diesel. For a truck covering 120,000 km per year in heavy transport, this translates to a saving of 18-20 tonnes of CO2 a year. But the greatest potential for savings is when the vehicle is powered by biogas, in which case tank-to-wheel CO2 emissions are reduced by 100 per cent. Furthermore, while fuel consumption is on par with Volvo Trucks’ diesel engines, it is 15 to 25 per cent less than conventional gas engines.
LNG is by no means a new fuel. However Volvo Trucks is the first to use it to deliver this level of horsepower in a heavy-duty gas truck.
Lars Mårtensson, Director Environment and Innovation at Volvo Trucks said: “LNG is promising as an alternative to diesel since it offers a good combination of both environmental and business benefits,” – “Natural gas is in high abundance globally, and the infrastructure network for LNG is expanding.”
“Until now the challenge has been that gas cannot be ignited by compression alone – you need something to start the gas burn process. Compression ignited diesel pilot is what ignites the gas in the engine,” explains Anneli Soppi, Chief Project Manager at Volvo Group Trucks Technology. “But that raises the challenge of how to inject two different fuels into the cylinder, since it is very difficult to have two injectors.”
The answer came in the form of two concentric needles that can inject both diesel and gas directly. Using this unique technology, a small amount of diesel is injected into the cylinder prior to the gas, to initiate the ignition.
“The diesel is essentially like a liquid spark plug,” says Anneli Soppi. “The engine runs predominately on gas – in fact it substitutes over 90 per cent of the diesel used in a conventional diesel engine, yet we still get all the advantages of a diesel engine, including the same high power and torque.”
For more information on how Volvo Trucks came up with their solution to tackle current emissions goals and what they plan to introduce in the future, read here.