The Saab BioPower 100 Concept, presented at the Geneva Motor Show, showcases the first production-based turbo engine to be optimized for pure, eco-friendly bioethanol (E100) fuel. The result is a level of performance never seen before from a road car using this fuel.
This exciting concept takes Saab BioPower technology to a new level by showing the true potential of combining turbocharging and sophisticated engine management with pure bioethanol fuel. And in demonstrating that greener motoring means even sportier driving, it also extends Saab’s technical leadership of Europe’s emerging ‘flex-fuel’ segment.
At the heart of the Saab BioPower 100 Concept is a modified version of a 2.0-liter turbo production gasoline engine from the current Saab 9-5 range, which in standard specification gives peak power of 150 hp. A test and development program - involving modifications to the engine management system and internal components - now enables it to exploit the high octane benefits of E100 fuel by using a higher compression ratio, together with more boost pressure. The outcome of this work is peak power of 300 hp and a remarkably high specific power output of 150 hp per liter.
“This exciting concept shows the tremendous potential of bioethanol, in terms of both performance and future opportunities to ‘rightsize’ engines,” says Jan Åke Jonsson, Saab Automobile’s Managing Director. “Bioethanol is already entering the European market as E85 fuel and we look forward to seeing further supply infrastructure developments that will make it more widely available in the future.”
The Saab BioPower 100 Concept is presented as an evolution of the Saab 9-5 SportCombi. It is visually distinguished by styling features such as ‘ice block’ front and rear light units – extending a theme seen on the 9-3 SportCombi - and 19-inch ‘turbine’ alloy wheels inspired by those of the award-winning Saab Aero X concept, first shown at Geneva last year. The interior is upholstered in unique white leather, complemented by the main fascia and door trims, which are finished in black leather overlaid with a carbon fiber-effect pattern. The car is also equipped with Saab’s innovative AlcoKey, an easy to use, pocket-sized alco-lock device that helps drivers steer clear of drinking and driving.
Saab is already established as the leading player in Europe’s emerging market for ‘flex-fuel’ vehicles able to run on gasoline and/or bioethanol (E85). Its current Saab 9-5 BioPower model is the best-selling flex-fuel car in Europe and Sweden and, at Geneva this year, Saab also announces BioPower’s introduction throughout its 9-3 product range.
So far, Saab BioPower development has been focused on using E85 fuel, (85% bioethanol/15% gasoline). Now, with the announcement of the fully functioning BioPower 100 Concept, Saab confirms its leadership position by showing how bioethanol technology could be further extended. In combining pure bioethanol with Saab’s expertise in turbocharging, the BioPower 100 Concept offers drivers an exciting win/win proposition: greener motoring with dramatically enhanced power and performance.
Running on E100, the concept car´s engine delivers peak power of 300 hp at 5,800 rpm and an exceptionally strong 400 Nm of torque between 3,000 and 5,100 rpm, withalmost 85% available at just 2,000 rpm. This strong and flexible power delivery gives the Saab BioPower 100 Concept car zero to 100 kph acceleration in just 6.6 secs and 80 - 120 kph (fifth gear) in an even more impressive 8.2 secs. The standard 150 hp gasoline engine produces 240 Nm of torque from 1,800-3,500 rpm, giving zero to 100 kph in10.2 secs and 80-120 kph (fifth gear) in 16.3 secs.
The secret behind such enhanced performance is the ability of E100 fuel to resist harmful self-ignition, or ‘knocking’, as the fuel/air mixture is compressed in the cylinder. This attribute is denoted by E100’s high 106 RON octane rating. It permits the use of an engine compression ratio that is higher than normally possible with turbocharging, giving more power and greater combustion efficiency without risk of knocking.
The BioPower 100 Concept’s engine operates with a compression ratio of 11.0:1, compared to 8.8:1 for the standard gasoline engine. This has been achieved by modifying the shape of the piston crowns to reduce the volume of the combustion chamber, thereby raising the engine’s compression ratio.
New software for Saab’s powerful Trionic engine management system, which controls the throttle setting, ignition timing, fuel injection and turbo boost pressure, looks after the different ignition timing and fuel/air mixture requirements of E100 fuel.
More durable valves and valve seats are fitted to the engine, together with bioethanol-compatible materials throughout the fuel system. The only other modification necessary is pre-heating of the fuel. This is required to achieve good cold-starting performance, which is the main reason why bioethanol is currently blended with gasoline and sold as E85 fuel.
In ambient temperatures below 15°C, the chemistry of E100 makes it resistant to vaporization and, as a result, it can be difficult to start the engine. To overcome this issue, the Saab BioPower 100 Concept has an experimental fuel heating system, using small heating elements in the inlet ports downstream of the injectors. When the engine is cold, these elements warm the incoming fuel sufficiently to allow it to vaporize. Shortly after start-up, the function is automatically deactivated.
On The Road
In optimizing the potential of bioethanol fuel, the Saab BioPower 100 Concept turbo engine offers improved driveability, as well as greater full power performance. The high compression ratio allows the engine to generate more torque more quickly, particularly from low engine speeds. On the road, the driver of the BioPower 100 Concept will immediately notice a sharper engine response, with a better low speed pick-up before the turbo is engaged.
On full throttle openings, the turbocharger packs up to 1.2 bar boost, without risk of ‘knocking’ from the high octane fuel. It gives the BioPower 100 Concept driver access to the sort of in-gear performance typical of a modern, naturally-aspirated engine of four liters or more. The smooth power delivery - without fossil fuel emissions - takes Saab’s traditional ‘less is more’ turbo philosophy to a new level.
That impressive 150 hp/liter specific power output also indicates considerable future potential for engine ‘rightsizing’, giving the driver the performance characteristics of a ‘large’ engine without incurring its additional weight, greater complexity or higher fuel consumption. In this way, E100 offers significant potential to reduce the displacement of an engine - thereby reducing fuel consumption - while still achieving a desired power level.
The overall fuel consumption of the current Saab 9-5 BioPower engine using E85 is about 30% higher than on gasoline and the optimized BioPower 100 engine is expected to yield a near 10% gain against this. Bioethanol burns at a lower temperature than gasoline, which reduces thermal stresses on the engine and benefits fuel consumption at higher cruising speeds. With the future addition of direct injection and lean-burn technology, E100 fuel consumption can move even closer to gasoline levels.
For optimum energy saving, future E100 applications could also be combined with electric hybrid technology, reducing fuel consumption and CO2 emissions still further. This development has already been previewed in the Saab BioPower Hybrid Concept, the world’s first such vehicle to use pure bioethanol.
Whilst the BioPower 100 Concept is focused on performance, it still retains a ‘flex-fuel’ capability and the engine will also run on gasoline, or E85, although power levels are not so high. Trionic monitors fuel quality after every visit to the filling station and automatically makes any adjustments necessary for running on E100/E85 and/or gasoline in any combination.
To handle the increased performance, the BioPower 100 show car is fitted with a limited-slip differential and larger front brake discs (345 mm) and calipers, while using the sports chassis settings of Saab 9-5 Aero SportCombi. It also has a dual pipe rear exhaust system, with tailpipes similar to those of the Aero X Concept.
Bioethanol is a clean burning fuel that can be produced in many parts of the world from a wide range of agricultural crops and biomass. More efficient second-generation processes, using ligno-cellulose extracted from forestry and agricultural products, are also under development.
Bioethanol’s simple, fixed chemical composition opens up new possibilities in engine management and control. It consists of just one hydrocarbon molecule, whereas retail gasoline is a cocktail of several hundred different hydrocarbons, as well as additives to prevent engine deposits which may not be necessary with bioethanol. It is also biodegradable and will dissolve in water.
As it is a single chemical compound, bioethanol allows engineers to exercise much greater precision in maximizing engine performance. For example, it is possible to maintain an ideal fuel/air mixture (Lambda 1) at all throttle openings without impairing the smooth running of the engine.
Saab’s experimental variable compression (SVC) engine, revealed at Geneva in 2000, has played an important role as a test bed for BioPower development work. It has been used to help determine the optimum relationship between compression ratio and boost pressure for the BioPower 100 application.
“Bioethanol is a potent, high quality fuel which opens up exciting possibilities in helping to meet the environmental challenges that face us,” says Kjell ac Bergström, President and CEO, GM Powertrain – Sweden, who has led the Saab BioPower 100 engine development team.
He adds: “As the need to reduce energy consumption increases, we are exploring ways to run smaller engines that give relatively high power, with and without hybrid technology. Bioethanol can play a key role in this ‘rightsizing’ process, while also minimizing fossil fuel emissions.”
Helping to Prevent Drink-Driving
The Saab BioPower 100 Concept incorporates Saab’s innovative AlcoKey, a vehicle ‘alcolock’ system designed to prevent the car being used if a driver is under the influence of alcohol.
The pocket-sized AlcoKey unit incorporates a cap covering a mouthpiece where the driver provides a breath sample before starting the car. Its radio transmitter then sends a signal to the engine’s electronic control unit. This will allow the car to be started or, if the breath sample is found to contain alcohol above the permitted legal level, keep it immobilized.
AlcoKey recently won the Swedish Automobile Association’s annual award for innovation and it is currently on user field trials in Sweden, where car fleet operators and public service providers want an effective means of reassuring the public that drivers cannot get behind the wheel if their blood/alcohol level is over the limit.
The field trials are focused on verifying AlcoKey’s convenience and ease of use. Its transmitter has a range of up to 10 meters and if a breath sample is provided before entering the car, its quick three to four second clearance process should not delay the driver. In everyday use, AlcoKey can provide a useful check if a driver has had a drink some time before intending to drive or has been drinking the night before. It could be offered as an option for Saab 9-5 and 9-3 models sold on the Swedish market, priced at around SEK 3,000.