Scania, a member of the Volkswagen Group, has launched its new OC13 13-liter (swept volume 12.7 liters) natural gas engine, based on Scania’s well-proven inline 6-cylinder, 13-liter engine. The Euro 6 engine works according to the Otto principle with spark plugs and complete combustion and delivers 410 hp (302 kW) @ 1,900 rpm with 2,000 N·m torque @ 1,100–1,400 rpm—well in line with diesel engines of a similar size.
There is a growing interest in operating vehicles on biogas or natural gas in countries such as Italy and France as a result of increased availability, improved infrastructure and good economic viability for truckers. FPT Industrial also recently introduced its newest and most powerful natural engine, the 13-liter Cursor 13 Natural Gas, specially developed for long-haul missions. (Earlier post.)
Scania’s gas engines are based on stoichiometric combustion, i.e. complete combustion of both fuel and oxygen. Similar to a gasoline engine, the combustion is initiated by means of spark plugs. The pre-mixing of the fuel takes place upon entry into the cylinders.
Criteria pollutant emissions are handled by Scania EGR and 3-way catalytic converter. The newly developed engine offers CO2 reductions of 15-90% compared to diesel, depending upon the source of the natural gas (e.g., biomethane).
Throughout development, our aim has been to ensure the best possible driveability. The performance and characteristics should correspond to that of a modern diesel engine.—Folke Fritzson, Senior Engineer at Scania R&D and part of the team developing Scania’s gas engines
The new 13-liter gas engine is always available with Scania Opticruise, Scania’s automated gearboxes.
Both LNG tanks (for refrigerated, liquefied gas) and CNG tanks (for compressed gas) can be ordered directly from Scania. With LNG, a semi-trailer truck of up to 40 tonnes can drive 1,100 km (684 miles) without refueling. With twin LNG tanks on rigid trucks, a range of up to 1,600 km (9994 miles) is possible.
In order to improve safety, Scania’s engineers have turned the tank valves backwards, away from the direction of travel. This is a seemingly simple but important detail that reduces the risk of the valves becoming damaged if hit by stones or gravel.
Gas engines that operate according to the Otto principle (with pre-mixing of fuel and spark plugs) have shorter service intervals than diesel engines. However, Scania has achieved a significantly longer service interval, with the lifespan of the spark plugs currently setting the limit.
We have defined the interval at 45,000 kilometers for both the spark-plug and oil changes with normal use. This is a clear improvement over previous generation gas engines, with 30,000 kilometers as normal intervals. This reduces maintenance costs and increases availability.—Folke Fritzson
Gas engines are generally quieter than diesel engines, and are therefore well suited for urban environments. Scania’s new Euro 6 gas engine meets the requirements of the PIEK noise limitation standard, which stipulates a noise level of no more than 72 dB(A) in areas with stringent noise limits.