Saab BioPower 100 Concept E100 Ethanol Vehicle

By Bill Siuru

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Saab’s 9-5 BioPower is Europe’s best selling E85 ethanol car. Saab, a leader in flexible-fuel and turbocharging technology, has broken new ground with it BioPower 100 Concept. An evolution of the Saab 9-5 SportCombi, this is the first production-based turbocharged engine to be optimized for pure E100 ethanol.

Saab’s objective was to show how “rightsizing” through turbocharging can give “large” engine power from small displacement engines. Pure ethanol, with its high 106 RON octane rating, allows higher compression ratios for more power than is normally possible with turbocharging, without harmful knocking (self-ignition).

The BioPower 100 Concept uses a modified version of the 2.0-liter turbocharged, four-cylinder gasoline engine used in the current Saab 9-5. Modifications to the engine management system and internal components allow the engine to fully utilize the benefits of E100’s high octane to allow a higher 11.0:1 compression ratio, compared to 8.8:1 for the gasoline engine. Also, a higher turbocharger boost, up to 17.6 psi, is possible without risk of knocking

The shape of the piston crowns were modified to reduce combustion chamber volume, thereby raising compression ratio. Also added were more durable valves and valve seats as well as bioethanol-compatible fuel system materials.

New software for Saab’s Trionic engine management system handles the different ignition timing and fuel/air mixture requirements of E100. The BioPower 100 Concept is still a flexible fuel vehicle being able to also run on gasoline or E85, but with reduced power. Trionic monitors fuel quality after every fill-up and automatically makes any adjustments for running on E100, E85, or gasoline in any combination.

Pure ethanol presents cold starting challenges, which is one of the reasons why 15 percent gasoline is added to create E85 and overcome this. So how did Saab handle the cold-starting problem inherent with running pure ethanol? Simply, innovation. The BioPower 100 Concept has an experimental fuel heating system with small heating elements in the inlet ports, just downstream of the injectors. Until the engine heats up, these ports warm the incoming fuel sufficiently so it vaporizes and overcomes the problem.

The bottom line is an increase in peak output power from 150 horsepower to 300 horsepower, resulting in a high specific power output of 150 hp-per-liter. Thus, the Saab BioPower 100 Concept car can accelerate from 0 to 62 mph in 6.6 second compared to 10.2 seconds for the regular Saab 9-5. According to Saab, the E100 version gives on demand performance typical of a 4-liter engine.

As expected, fuel consumption is higher with E100 because of ethanol’s lower energy density, but Saab believes that E100 fuel consumption can move closer to gasoline levels with the future addition of direct injection and lean-burn technology. Also, E100 could be combined with hybrid technology as Saab has already shown its BioPower Hybrid Concept.