Saab is displaying a new crossover concept at the 2008 North American International Auto Show called the 9-4X BioPower.

This concept is a preview of an upcoming new production model from the Swedish brand. Following the pattern set by most recent Saab concepts and many of their production cars in Europe, the 9-4X is powered by a flex-fuel engine.

In Sweden the government has set a target of replacing all fossil fuels with renewable equivalents by 2020. In an effort to help meet that goal, Saab has been heavily promoting their flex-fuel engines under the BioPower brand. BioPower Saabs now comprise over 90% of the company's sales of the 9-5 model in the brand’s home market.

Overall, from January through November 2007, two-thirds of Saab sales in Sweden were BioPower models while 21% of total European market sales were of that type.  Saab is the top selling brand of E85 capable vehicles in Europe capturing 44% of that segment. 

The 9-4X is a mid-sized CUV based on a variant of General Motors’ "Theta" platform that's also used for the Saturn Vue and Opel Antara. Power comes from a new all aluminum 2.0L four cylinder engine that the Swedish brand is promoting as "right-sized." The powerplant incorporates technologies that Volkswagen has been using for several years that are becoming increasingly common.

The new Saab will be built in Mexico and is bound for the US. GM hasn’t set a market date, but the 9-4X is expected to join dealerships sometime in 2009.

The idea of a smaller displacement engine using turbocharging and direct fuel injection is gaining popularity as an alternative to larger displacement engines. The smaller displacement boosted engines have the advantage of lower fuel consumption and emissions while also reducing mass of both the engine and the vehicle.

As a result of the emphasis on ethanol use in its home market, Saab has optimized the 9-4X concept engine for operation on the biofuel. Most current flex-fuel engines are tuned primarily for gasoline use with the main changes being the fuel content sensor and higher flow fuel injectors.

Ethanol has a lower energy content than gasoline at about 75,700 Btu/gallon compared to 125,000 Btu/gallon. However, it has an octane rating of approximately 104 compared to 91-93 octane for premium pump gasoline in the US. The lower energy content means that unaltered, a normally aspirated engine will produce less power and use more fuel than with ethanol than gasoline. The higher octane rating allows more spark advance to be used, gaining back some of the power.

Enhanced engines, such as the one in the 9-4X, have an advantage when running on ethanol because the boost levels can be increased compared to gasoline. The new Saab engine also uses a higher compression ratio of 10.5:1 than the 9.2:1 that would be used for an equivalent turbocharged gasoline engine. The lower octane of pump gasoline could result in pre-ignition and engine damage with the same settings.

Variable valve timing is incorporated on both the intake and exhaust camshafts and fuel is injected directly into the combustion chambers. Both of these technologies contribute to improved drivability as well as reduced fuel consumption and emissions.

Running on E85, this new engine has a maximum output of 300hp and 295lb-ft of torque. The latter figure is maintained from 2,600 to 5,100rpm and even at 2,000rpm over 250lb-ft is available. If gasoline is used the engine management system will retard the spark timing and turbo boost resulting in less power but protecting the internals from damage.

JANUARY 2008