Saab chose the London motor show for the world premiere of the 9-5 2.3t Biopower. Part of the facelifted 9-5 range, the 2.3 litre variant – able to run on E85 bioethanol, petrol or any mixture of both – joins the 2 litre model, which the company says is Sweden’s best selling environmentally-friendly vehicle.
E85 is a popular in Sweden , where the commonly used biomass is wood pulp and forest residue. Saab claims using E85 bioethanol instead of petrol can cut fossil CO2 emissions by up to 70 per cent, echoing similar views expressed by Ford in its recent announcement about improving the environmental performance of its models.
Provisional figures, pending homologation, show the four cylinder engine producing 210 bhp (157 kw) and 310 Nm torque from E85, compared to 185 bhp (138 kw) and 280 Nm when fuelled on petrol, and cuts the sprint to 62mph (100 km/h) from 8.5s to 7.9s.
The Trionic engine management system optimises turbocharger boost pressure and ignition timing to take advantage of E85’s octane advantage compared to premium unleaded: 104 RON vs. 95 RON. The greater knock resistance of E85 allows greater boost and more advanced timing: important given that ethanol has a lower specific energy content than gasoline.
All controlled parameters are adjusted for any given mix of fuels in the tank.
The usual changes have been made to account for alcohol’s reduced lubricity and greater corrosiveness than petrol: engine valves and seats are hardened, and ethanol suitable materials used throughout the fuel system.
Jan-Åke Jonsson, managing director, Saab automobiles, says: “The launch of a 2.3 turbo model is the logical next step in the roll-out of our highly successful Biopower concept. It is being offered in response to customer demand for an eco-friendly vehicle that delivers even more performance and is the first in a number of future Biopower initiatives that we have under development.”
Shown alongside the 9-5 models, and seen for the first time outside Sweden , was the 9-3 Biopower convertible hybrid concept. Hailed as the first fossil fuel free hybrid, the car uses pure bioethanol E100 together with 300V Li-ion battery power, but retains flex fuel capability: the car can still run on gasoline.
 |
| 9-3 BioPower hybrid: E100 means fossil-free driving |
Saab has further developed its 2 litre biopower engine to extract maximum advantage from E100’s octane rating to produce 260 bhp (194 kw) and 375 Nm torque.
A new direct injection system dubbed SIDI is used, to counter the cold start problems associated with bioethanol; alcohol fuels have a lower vapour pressure than gasoline.
Power is fed through the dual mode hybrid system developed by BMW, Daimler Chrysler and GM, as reported in the May issue of Automotive Engineer. The system features an electric continuously variable transmission (ECVT) and two 75 bhp (56 kw) motor/generators. A rear drive unit features a 55 bhp (41 kw) motor/generator, giving the car electric four wheel capability.
Jonsson said: “This concept allows us to evaluate and explore the potential of hybrid technology in combination with Biopower. As part of this process, we are now developing our expertise further by the two-mode hybrid technology. It shows how we can continue to express the sporty performance associated with Saab while using renewable resources and saving energy overall.”
A switch allows the car to be driven on electric power only at speeds below 31mph (50 km/h) – “city mode” – giving a range between 6 and 12 miles (10-20 km), depending on driving conditions.
Projected performance figures suggest acceleration from 0-62mph (0-100 km/h) in 6.8s, with top speed limited to 155mph (250 km/h).
|
[BACK TO TOP]
|
.jpg)