Saab BioPower for ‘Green Performance’
On the ground and in the air, the Aero X promises exceptional levels of performance. The BioPower V6 twin-turbo engine not only delivers impressive power, it also offers the prospect of zero fossil CO2 emissions.
• Next step in Saab BioPower technology
• 400 bhp, 2.8-liter V6 engine
• 100% bioethanol for zero fossil CO2 emissions
• Saab Active Chassis for greater driving safety
• All-wheel-drive with variable front/rear torque split
• Seven-speed, double clutch automated manual transmission
The Aero X concept showcases the potential of Saab BioPower to offer drivers ‘green performance’: increased engine power with a greater regard for the environment.
Running on 100% bioethanol, a renewable and sustainable fuel, its advanced 2.8V6 BioPower engine delivers 400 bhp maximum power at 5,000 rpm and massive torque of 500 Nm between 2,000 and 5,000 rpm. Computer simulations anticipate zero to 100 kph acceleration in just 4.9 seconds and a 250 kph (limited) top speed.
For optimum handling, the powertrain is mounted entirely behind the front axle line, giving the Aero X a near perfect 50/50 weight distribution. All-wheel-drive, with a variable torque split between the front and rear axles, provides superb traction and Saab Active Chassis, with continuously variable damping, gives excellent real-life driving safety and control.
By combining bioethanol with turbocharging, Saab BioPower exploits the high octane performance of this fuel, as well as its environmental benefits. The technology is already well-proven by the outstanding sales success of the Saab 9-5 2.0t BioPower in Sweden and its introduction on other markets.
For the Aero X, Saab takes BioPower to a new level by using pure bioethanol (E100) fuel, with a higher octane rating of 106 RON compared to gasoline’s 95 RON. Using a 12:1 compression ratio and twin turbochargers running at 1.0 bar boost, this high-feature engine delivers an impressive 143 bhp/ per liter. Turbocharging with E100 fuel allows the use of a higher compression ratio – giving more engine power – than is possible with gasoline because of the risk of harmful ‘knocking’ or pre-detonation.
The all-aluminum, 24-valve, four-cam engine is a high performance development of the current version in the Saab 9-3 range. For the Aero X, it is longitudinally installed and features a Spark Ignited Direct Injection system (SIDI) for optimum combustion; variable inlet and exhaust cam phasing for improved breathing, and dry-sump lubrication for a lower chassis installation and reduced oil pumping losses. Both turbochargers have variable geometry turbine (VGT) wheels to give a quick low-end response.
More durable valves and valve seats are fitted, together with bioethanol-compatible materials in the fuel system, including the tank, pump, lines and connectors. The addition of the SIDI system ensures the same cold starting performance as a normal gasoline engine.
The 32-bit engine management system simultaneously controls the ignition timing, fuel injection, turbo boost pressure, air mass measurement and the throttle setting. For minimized exhaust emissions, the two close-coupled catalysts are equipped with electronically controlled, secondary air injection, which gives extremely quick ‘light-off’ following cold starts.
By using 100% bioethanol, the Aero X driver can enjoy ‘supercar’ levels of performance – without raising atmospheric levels of CO2, the ‘greenhouse’ gas that is regarded as a major contributor to global warming. Bioethanol fuel is produced commercially from agricultural crops or forest residues. Unlike gasoline, its consumption does not add more CO2 to the atmosphere because emissions during driving are balanced by the amount of CO2 that is removed from the atmosphere when crops for conversion are grown. In this way, the CO2 already present in the atmosphere is simply recycled, whereas the use of a fossil fuel, such as gasoline or diesel, releases new amounts of CO2 which have been locked away underground.
"Turbocharging and bioethanol make excellent partners," says Kjell ac Bergström, Executive Director of Saab Automobile Powertrain AB. "In developing this BioPower V6 engine we have been able to take the next step by using E100 fuel, pure 100% bioethanol. That means there are zero fossil CO2 emissions because we are not using any gasoline at all.
"Although the engine is optimized for E100, the engine management system will still make adjustments for any bioethanol/gasoline blend in the tank. So, if there is no bioethanol available, the customer can still use gasoline at any time."
The sophisticated, seven-speed automated manual transmission uses a wet double clutch system to allow fast, full throttle, sequential gear changes via the steering wheel paddles. Power is transmitted to all four wheels through a multi-plate clutch, allowing an infinitely variable front/rear torque split.
Saab Active Chassis
Suspension is by double wishbones at the front and an independent multi-link layout at the rear. Continuously adjustable damping (Saab Active Chassis) is adopted for enhanced body control, ride comfort and driving safety.
Saab Active Chassis involves processing signals from a number of on-board sensors which measure the vehicle’s vertical, lateral and body-in-roll movements. These inputs are fed into a central control unit, which monitors the behavior of each wheel as often as 100 times per second. It can then calculate and make small adjustments to the valving of each relevant damper as required in just 10-30 milliseconds. Opening the valve increases oil flow to allow softer damping, while closing the valve produces firmer damping. A range of pre-settings can be selected by the driver.
The Aero X has stopping power to match its performance. Large brake discs (380 x 34 mm, internally ventilated front and rear) clasped by eight-piston, monobloc aluminum calipers ensure rapid and virtually fade-free retardation.