Scania’s new 13-litre engine can be specified on a range of G- and R-series trucks, including 4×2 tractor units and 4×2, 6×2, and 8×4 rigids, with vehicles operating on compressed natural gas (CNG), compressed bio gas (CBG) or liquefied natural gas (LNG). In CNG/CBG format, a total of eight gas tanks are fitted.
These are either 95 or 118 litres each, depending on wheelbase and battery position, giving a maximum capacity of 944 litres. This equates to a range of up to 500 kilometres, depending on road conditions and application.
For LNG tractor units, two tanks provide a capacity of 740 litres and a range of up to 1,000 kilometres, while LNG rigids can accommodate single or double tanks, giving a capacity of 400-1,100-litres and a maximum range of up to 1,600 kilometres.
Designated OC13 101 and based on Scania’s proven six-cylinder 13-litre diesel platform, the new dedicated gas-powered unit utilises the Otto principle and stoichiometric combustion, where all fuel and oxygen is burnt completely. Combustion is initiated using spark plugs, and pre-mixing takes place prior to the fuel entering the cylinders.
Andrew Jamieson, sales director of Scania (Great Britain), said: “With 2,000 Nm torque from 1,100rpm through to 1,400rpm, the new 13-litre gas engine delivers similar performance to comparable diesel engines.
“Furthermore, when running on biogas, emissions of carbon dioxide are reduced by up to 90 per cent. As such, this new engine will appeal to operators looking to switch to a renewable and sustainable fuel source while reducing their environmental impact, without compromising performance.”
The new 13-litre engine has been designed to operate with Scania Opticruise, Scania’s fully-automated gear selection system, ensuring fast and smooth gear-changing and high levels of driver comfort.
Gas engines operating on the Otto principle (with pre-mixing of fuel and with spark plugs) have shorter service intervals than diesel engines, with spark plug life as the key determinant.
Senior gas engine R&D engineer Folke Fritzson said: “We have set the interval at 45,000 kilometres for both spark plug replacement and oil changes under normal use. This is a clear improvement over previous generations of gas engines, which had a normal service interval of 30,000 kilometres, and therefore reduces maintenance costs and increases uptime.”
The introduction of the 13-litre gas engine provides a competitor to Iveco’s 460 Stralis NP, and the soon-to-be launched 420 and 460 hp Volvo FH and FM trucks.
While the Iveco, like the Scania, uses spark-ignition and indirect injection, Volvo has opted for Westport/Delphi technology which injects both gas and a small amount of diesel (which acts as the ignition medium) through the same injector (Transport Operator 67).