Scania’s latest gas engine designed for long-distance transport

Thursday, November 9, 2017

Scania’s launch of the OC13 gas engine marks the start of alternative fuel solutions for the new truck generation. The OC13 is based on Scania’s well-proven 13-litre engine and works according to the Otto principle with spark plugs and complete combustion.

Improved infrastructure and good economic viability has seen a growing interest in operating vehicles on biogas or natural gas, and the sustainability aspects are also important – even natural gas provides a CO2reduction of approximately 15 percent.

Scania’s gas engines are based on stoichiometric combustion, i.e. complete combustion of both fuel and oxygen. Similar to a petrol engine, the combustion is initiated by means of spark plugs. The pre-mixing of the fuel takes place upon entry into the cylinders.

“Throughout development, our aim has been to ensure the best possible driveability,” explains Folke Fritzson, senior engineer at Scania R&D and part of the team developing Scania’s gas engines. “The performance and characteristics should correspond to that of a modern diesel engine.”

The tank solutions are an important aspect of gas fuel operations and both LNG and CNG tanks can be ordered from Scania. LNG always provides greater range, as a significantly larger amount of fuel is available.

“In combustion, there is no difference between LNG and CNG, but there are significant differences in the operational range,” says Fritzson. “With LNG, it's up to 1,100 kilometres for a typical semi-trailer on a flat road. CNG usually provides a range of up to 500 kilometres. The latter is more than sufficient for many customers.”

In order to improve safety, Scania’s engineers have turned the tank valves backwards, away from the direction of travel. This reduces the risk of the valves becoming damaged if hit by stones or gravel.

Gas engines that operate according to the Otto principle have shorter service intervals than diesel engines, but 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 kilometres for both the spark-plug and oil changes with normal use,” says Fritzson. “This is a clear improvement over previous generation gas engines, with 30,000 kilometres as normal intervals. This reduces maintenance costs and increases availability.”

“Everything indicates that we are heading towards a breakthrough for gas engines, including heavier trucks for long-distance transport and construction-site vehicles,” says Henrik Eng, product director urban, Scania Trucks. “We also see that the rapidly growing gas infrastructure in several European countries spurs interest in using this alternative fuel.”

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.

Technical data

 

OC13 101

Type

Inline

Cylinder capacity

12.7 litres

Firing sequence

1-5-3-6-2-4

Cylinders

6

Valves per cylinder

4

Bore x stroke

130 x 160 mm

Cam type

Normal

Compression

12.6:1

Fuel injection

Bosch

Emissions treatment

Scania EGR and 3-way catalytic converter

Oil volume

43 litres

Max power

410 hp (302 kW) @ 1,900 rpm 

Max torque

2,000 Nm @ 1,100–1,400 rpm