Saab reinvents the convertible with the 9-X AIR CONCEPT

The Saab 9-X Air now takes this proven flex-fuel technology further with an engine that fully exploits the high octane benefits of E85 fuel. It uses a higher compression ratio (10.2:1) and turbo boost pressure (up to 1.6 bar) than would be possible with a petrol-only engine. This is because E85 has a higher octane rating (104 RON) than pump petrol (95 RON), which makes it more resistant to harmful pre-detonation, or ‘knocking’, as the fuel/air mixture is compressed in the cylinder.

Running on E85 fuel, this lightweight yet sophisticated BioPower engine delivers the power characteristics of a much larger powerplant. That impressive torque of 280 Nm (207 lb.ft), for example, is available all the way from just 1,750 to 5,000 rpm. It’s another demonstration of Saab’s rightsizing engine strategy – offering exceptional power without the greater weight, size, fuel consumption or emissions of a larger, naturally-aspirated engine.

Whilst optimised for E85, the engine retains a flex-fuel capability and will still run on petrol, although it will not produce as much power. The engine management system is able to adjust the ignition timing and boost pressure to ensure there is no pre-detonation due to the higher compression ratio.

The advanced specification of this engine also includes direct injection (DI), with centrally-located fuel injectors, and continuously variable valve timing (VVT) on both the inlet and exhaust sides. The result is greater low-end torque and further improved fuel consumption.

Next-Generation GM Hybrid System

Fuel consumption and CO2 emissions are reduced yet further by the addition of the next-generation GM Hybrid system, which features a significantly higher power capability to capture more energy and more electric boost than the current GM Hybrid system. An electric motor/generator, belt-driven from the engine’s crankshaft, replaces the conventional alternator. Electrical power is delivered and stored by the compact lithium ion battery pack, located under the rear cargo floor.

At take-off from rest and during overtaking manoeuvres, the electric motor adds accelerative power. It is also used to re-start the engine, supporting the automatic fuel-saving function whenever the car is stationary. To further improve efficiency, the hybrid system enables a longer fuel cut-off during deceleration and braking.

The electric motor also acts as a generator. It can be powered by the engine to charge the battery pack and support vehicle electrical loads. Or it can be used for ‘regenerative braking’ by capturing the vehicle’s kinetic energy when decelerating and storing it in the battery pack. Sophisticated electronics manage AC/DC and all voltage interfaces, including the 12-volt in-car supply.

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