Scania’s new powertrain improves fuel consumption in city buses
7 DECEMBER 2020
For bus operators, fuel is one of the main costs. This makes it essential to choose the right bus for each operation. Scania’s new bus generation saves fuel in several ways, as the weight of both chassis and body are significantly lower than before. The new engines are considerably more efficient, and the start-stop function adds further to the fuel savings.
“We know that the environmental aspect is important when operators choose their vehicles,” says Anna Gustavsson, Product Manager for City & Suburban Buses in Europe. “And since a vehicle’s fuel consumption is directly related to its CO2 emissions, a fuel saving also means a decrease in emission levels.”
Less weight has an impact
The various improvements on Scania’s city bus contribute to a better fuel economy. “Carrying unnecessary weight always costs fuel. That is why we have introduced major weight savings on the new generation. The new body concept saves no less than 800 kg on low-floor buses and 400 kg on low-entry buses.”
The improved engines
All engines have been updated and upgraded for the new bus generation and have also been tuned for more torque at low revs, which reduces the need for changing gears, while contributing to a silent, relaxed ride. “The 7-litre engine is optimised for urban operations, and the powertrain is truly made for city traffic.”
Start-stop
The start-stop function – a really good match with the 7-litre engine – switches off the engine when stopping, either at bus stops or in traffic. Besides saving fuel, shutting off the engine reduces noise and emissions.
How we measure
The Standardised On-Road Test (SORT) is an established way of assessing performance and fuel economy. With this test. it is easy to compare different bus configurations and competitors over corresponding routes. “Our new low-floor buses show significant improvements in these tests thanks to the new chassis concept, with its inline, longitudinal powertrain,” says Niklas Berglund, Expert Engineer at Energy Consumption, Bus Chassis Development.
The low-floor bus with the 7-litre engine really stands out, boosted by the SCR-only (Selective Catalytic Reduction) emission technology. “The fuel consumption has gone down by up to 9 liters/100 km resulting in a SORT consumption below 31 liters/100 km, an excellent result both in comparison with the performance of previous generations as well as our competitors.” If fossil-free fuels are used, the carbon footprint is close to nothing.
“We are truly happy to offer this improved city bus to our customers. Lower chassis and body weight, more efficient engines and start-stop are the main contributors to less environmental impact and lower costs.”
Weight:
Low-floor chassis : the shift from a transverse to a longitudinal engine, with an inline powertrain saves up to 200 kg.
The new longitudinal powertrain is more efficient and cuts fuel consumption by 2–3%, and the weight saving on chassis another 0.5%.
On the three-axle low-entry buses, the new electro-hydraulic tag axle saves both weight and fuel since it only operates when needed energy is saved.
Engines:
The 7-litre engine is now fully integrated in the Scania range in terms of function, installation and maintenance, with service intervals on a par with other Scania engines.
The 9-litre engine has been revised to reduce internal friction and has a higher compression ratio that further improves efficiency.
The 9-litre gas engine has also been improved with more torque at low revs, which improves both driveability and efficiency.
