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Scania to Unveil Ethanol-Fueled Series Hybrid Bus Concept

Scania’s ethanol hybrid.

Scania will introduce its ethanol-fueled hybrid bus concept at the UITP public transport congress in Helsinki 21-24 May 2007. The full-size low-floor city bus is designed to cut fossil CO2 emissions by up to 90% when running on the ethanol blend and reduce fuel consumption by at least 25%.

The series hybrid powertrain combines a 9-liter diesel engine genset adapted to run on ethanol with a 150 kW traction motor and 4 125V Maxwell BOOSTCAP supercapacitors for energy storage. The new Scania concept bus, which also meets Euro 5 and EEV emissions standards, is the result of a three-year development project conducted at the Scania Technical Centre in Södertälje, Sweden.

The series hybrid configuration. Click to enlarge.

The engine is an adaptation of Scania’s latest 9-liter diesel engine with air-to- air charge cooling and exhaust gas recirculation, EGR. The 5-cylinder engine has unit injectors for each cylinder and a compression ratio of 28:1.  Power output is 199 kW (270 hp) at 1,900 rpm and torque is 1,200 Nm (885 lb-ft) at 1,100-1,400 rpm. The engine is mated to a water-cooled Voith ELVO Drive TFM Generator.

The traction motor is a water-cooled Voith ELVO Drive which delivers maximum torque of 2,750 Nm (2,028 lb-ft), and continuous torque of 1,800 Nm (1,328 lb-ft) with a maximum speed of 2,400 rpm.

Supercapacitors on the roof. Click to enlarge.

The Maxwell supercapacitors store more than 400 Wh of energy.

Twelve conventional ethanol buses equipped with Scania’s hybrid-drive system will start regular operation in Stockholm in 2008 and 2009 in cooperation with the city’s public transport operator, SL (Storstockholms lokaltrafik). Ten of these are partly financed by the Swedish Energy Agency.



This is the eventual architecture of the US large SUV, I think a Deisel Genset would be better, if ethanol gives a 25% improvement in fuel consumption then diesel should be at least 50-60%

How cool would it be if we could have SUV's doing 30-40 mpg of BioDiesel


This looks like a fine application.

And as is often true when the announcement comes out of Europe it is actually being done. Now, not someday.

I'm also glad to see the Maxwell SuperCaps mentioned. This is exactly the sort of vehicle that can use them.

Finland has plenty of wood stock. If celluosic ethanol can be produced in volume it can remove an entire nation, albeit a small one, from the fossil fuel mess.


Great to see more market acceptance for hybrid buses, but the numbers given don't seem to make sense. Based on the energy return of producing ethanol, a 25% reduction in fuel use doesn't seem like it would produce a 90% reduction in green house gases.

In the US I believe it's estimated that at best 1.3 units of ethanol energy are produced for each 1 of fossil fuels used in it's making. Does anyone know why this would be radically different in Finland? Otherwise, it would seem only about 40-45% CO2 reduction... certainly nothing to sneeze at, but it's not 90%.


We don’t have the exact breakdown of numbers behind the 90% cut in CO2 reduction. However, here are three reasons: 1) The mentioned 25% reduction in fuel use. 2) Finland produces less than 40% of its electricity from fossils compared to about 70% from fossils in the US (and that electricity is used for ethanol production). 3) The shift from diesel to ethanol also means that CO2 that are released for energy use when drilling fossil oil, transporting it and refining it is saved.

Maybe I should add that not only does Finland have plenty of wood stock. So does Sweden and Norway. Plus Russia has enough wood stock to supply the rest of EU with cellulose ethanol when this technology is ready. They will probably try to sell fossil fuels but I think that at some point global warming will be so threatening to and destructive for the survival of other species that eventually all use of fossils will be banned.


Why all this talk about Finland? The bus is developed in Sweden, by a Swedish company, and will be used in Stockholm in Sweden. It will only be displayed in Finland.


Good enough. I remembered Helsinki when I began to type the comment.

Sweden it is.


It seems odd to use ethanol in a diesel engine. Ethanol has higher octane that works well in high compression gasoline engines, but diesel fuel is rated for cetane. I would think that extensive engine changes would have to be made. It makes me wonder why they did not use biodiesel.

Of course, they run diesel buses on CNG and that is very high octane and at 28 to 1 compression, I guess it might not matter much, except for cold starts.

Michael Franke

Hi all,

running a diesel engine on ethanol is not such a big think and works similiar to CNG. Minor changes in engine management and some modifications on injection parts to compensate for higher pressure and more aggressive fuel.
Cold start is not really a topic for a city bus. Normally standing in a building overnight it runs all day long. Of course with the hybrid the engine will be switched off now and then.
90% CO2 reduction was related to fossil emissions using ethanol instead of diesel. Of course the emissions at the exhaust are much less, but nearly CO2 neutral.
Sweden is serious about becoming fossil oil independent. The huge number of ethanol gas stations and the availability of E85 vehicles (E100 from Saab coming soon) is a clear statement.
By the way, nearly all buses in small Liechtenstein run on CNG.
Greetings from Ethiopia.

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