Click the Flextreme for a high-res gallery


We all got an early look at the Opel Flextreme after the images leaked onto the web the other night. In case you missed it, the Flextreme is Opel's interpretation of the E-Flex architecture that debuted last January in Detroit. Unlike the low-slung, almost coupe-like sedan shape of the Chevy Volt, the Opel features a similarly sleek mono-box shape. The more utilitarian wagon/hatch body style has always been popular in the European market where smaller more efficient cars dominate.

When General Motors gave us the first glimpse of E-Flex just before the Detroit Show, they emphasized the flexibility of the power-train architecture. As a system that is designed to be primarily electrically driven, the AC motor and battery packs are common across all variants. But as we move into a future where world-wide energy demands are increasing and petroleum gets more expensive, locally-soursed fuels will become the norm.

Full details of the Flextreme after the jump.
Related Gallery2007 Opel Flextreme concept

[Source: General Motors]

General Motors has developed a power-train architecture that is easily adapted to whatever fuels are locally available. Essentially the only thing that changes as you go from one E-Flex type to another is the source of electricity for that motor. All of the versions have the ability to be plugged in to a local electrical outlet and draw power from the grid or whatever non-centralized sources might be available.

The original Volt added a gasoline/E85 flex-fuel 1.0L three cylinder engine mated to a 53kW generator to provide on-the-go energy to the battery. The version they showed in Shanghai in April of this year swapped the internal combustion engine for a hydrogen fuel cell. This was done because China is expected to take the lead on hydrogen infrastructure development as their energy requirements and air pollution continue to get worse. In Europe, where diesel engines are already the majority in many countries, the obvious choice for the Opel E-Flex was a diesel range extender.

The Flextreme uses an Opel 1.3L four cylinder common-rail diesel engine to drive its generator. There have been some changes to the configuration of the Opel compared to the Chevy. On the Volt, the range extender sits above and slightly behind the electric motor. On the Flextreme the diesel has been moved out in front of the motor. According to E-Flex Vehicle Line Director Tony Posawatz, this was in part due to the monobox design of the Flextreme. The proportions of the design didn't work as well with the longer hood of the Volt layout. One of the advantages of the E-Flex is that the decoupling of the engine from the drive wheels allows the designers to reposition components like this more easily.














Looking at the two cars in side profile, the difference in the front overhang is clearly visible. It's not known at this time if the production Volt will get the same change in configuration. The Opel does look like it will have better forward visibility than the original Volt design.



Speaking of the design, the Flextreme picks up design cues from last spring's Opel GTC concept that debuted in Geneva. The scalloped shape of the side panels appeared on the earlier concept and have also been clearly visible on many of the spy photos of the next-generation Opel Vectra. Up front, the air ducts that extended down from the headlights of the GTC are carried over to the Flextreme but now curve outward at the bottom.

Since the GTC was developed as a vision of a future Opel performance coupe it features larger air openings to provide adequate air flow for cooling. The Flextreme is intended for maximum efficiency so drag reduction necessitated closing off as much of the front face as possible to get air flowing around the car. The new concept has much smaller front air intakes than most production Opels.

At the rear corners the pronounced shoulders above the rear wheels from the GTC also appear on the new E-Flex concept. The cut-line on the rear edge doors of the Flextreme is shared with the rear cargo openings which are made up of a pair of gull-wing style hatches. While these look cool on a concept they are unlikely to make it to a production car anytime soon. The same goes for the rear hinged back doors. Designers like to use these on concepts because it makes it easy to show off the interior on a rotating show stand. The loss of structural integrity from the missing B-pillar, especially for side impact, makes these even more unlikely for production.

One design element that will probably eventually come to the showroom is the rear-view cameras. Rear-mounted back up cameras are already becoming fairly common on new cars. With the gull-wing rear hatches, this car has a thick pillar in the middle of the rear but a camera mounted at the top gives rear visibility. Similarly, cameras mounted at the base of the A-pillars negates the need for side mirrors, which has a big benefit for aerodynamics. Up top, the Opel E-Flex has glass roof that incorporates the windshield and is bisected by a slim solid section that the rear hatches hinge from.

Another area where the Flextreme design differs from the Volt is the what's located under the rear cargo area. A special compartment opens up behind the rear bumper revealing a storage area for two Segway scooters. The compartment has charging ports for the Segways so that they can be pulled out and used in areas where cars might not be allowed. The Segways provide an extra 23 miles of mobility.



One cost of the storage space for the scooters is less space for a fuel tank. The Flextreme only has capacity for 7 gallons of diesel fuel on board. In spite of the same 16kWh lithium ion battery rating as the flex-fuel Volt, the battery-only range has also decreased from 40 miles to 34 miles. All of this combined with a weight increase due to the diesel and the two Segways and degraded aerodynamics compared to the Volt means that the ultimate range of the Opel dips from an estimated 640 miles to 444 miles. The target for the production version of the Volt remains at 40 miles on the battery. On the plus side the 220V outlets that are standard issue in Europe will be able to charge the battery in half the time of our 110V, with a full charge coming in a little over three hours.

In GM's computer simulations of the E-Flex doing the current European test cycle (ECE R101) they achieved a carbon dioxide emissions rating of 40g/km. That's less than half of the current production champ, the Smart ForTwo CDi which is rated at 88g/km. The Flextreme manages this in a four-seat package with substantial cargo capacity. The proposed EU regulations call for a fleet average of 130g/km and the Flextreme would go a long way toward helping GM achieve that goal.

Now they just have to build production vehicles with E-Flex. General Motors is currently running some "mule" vehicles with non-representative hardware. That means they are using current production vehicles that are modified with components and systems from the new vehicles in order to develop those systems and the related controls software and electronics. They are also bench testing lithium ion cells from suppliers Compact Power and A123. The first prototype full battery packs are scheduled for delivery and bench testing later this fall. Once those have been tested, they will go into the first real prototypes early next year.

GM currently has over 150 engineers working on E-Flex development and they are focusing on the flex-fuel and fuel cell variants first. The diesel variant may come later. Either way, this is a production program targeted for launch at the end of the decade. As long as they don't hit any major potholes with the batteries, we should see something based on these concepts in that time frame.



GM Press Release:

Opel Flextreme Concept Expected to Achieve Less Than 40 gm/km CO2 Emissions
Plug-in Electric Vehicle Features 55 Km of Emissions-Free Range

FRANKFURT – General Motors Corp. today unveiled the Opel Flextreme concept electric vehicle, which based on the current European test cycle for plug-in vehicles is expected to emit only 40 g of C02 per kilometer (km), at the International Motor Show (IAA) in Frankfurt.

The Flextreme uses a diesel version of GM's E-Flex electric-drive system. In contrast to conventional vehicles and hybrids, E-Flex uses an electric motor, powered by a large lithium-ion battery, to propel the Flextreme for up to 55 km (34 miles) of electric-drive-only range. A 1.3 L turbo-biodiesel onboard engine creates additional electricity to replenish the battery and extend the vehicle's driving range to a total of 715 km (444 miles). Fully charged, the Flextreme's 55-km all-electric driving range is enough for most daily commuters in Europe to travel without using any diesel fuel or emitting any CO2.

"The Opel Flextreme diesel concept, the third variant of our E-Flex system, is a natural for the Opel/Vauxhall brand in Europe, where it has long been known for technological innovation and strong design," said Bob Lutz, GM Vice Chairman Global Product Development. "Commutes to major city-centers in Europe will do nothing but grow more challenging in the future, and we see E-Flex vehicles as an elegant solution for commuters."

With the E-Flex system, the generator, battery technology, plug and electric motor are the same in each variant – the source of additional electricity is what varies. The Opel Flextreme's 1.3 L common-rail diesel engine, which is not connected to the wheels, features a cylinder pressure-based closed loop process to control the combustion process and further reduce the vehicle's exhaust emissions.

The Flextreme's electric propulsion architecture also supports two Segway electric scooters with docking stations that are integrated into the vehicle's cargo area. The electric scooters are capable of up to 38 km (23 miles) of range, offering European customers greater access to places where cars are not allowed.

The E-Flex system was first shown in the Chevrolet Volt concept, which had its debut in January at the North American International Auto Show in Detroit. Volt is powered by a 16 kWh lithium-ion battery to power the vehicle for 64 km (40 miles) of all-electric range. A small biofuel engine with a generator is used to extend its range to more than 1000 km (640 miles).

A second E-Flex variant was shown in Shanghai with GM's new fifth-generation fuel cell propulsion technology and an 8 kwh lithium-ion battery to provide up to 483 km (300 miles) of petroleum- and emissions-free electric driving.

GM has initiated production engineering for the E-Flex System. Production timing is dependent on continued advances of key enabling technologies – specifically the development of lithium-ion batteries for hybrid and electric vehicle applications.

"We fully intend to bring this technology to market," said Frank Weber, Vehicle Line Executive and Vehicle Chief Engineer for the E-Flex system. "Although the battery required for the E-Flex system is still being developed, we're increasingly confident that our strategic battery partners – Compact Power, Inc.; and LG Chem, Continental Automotive Systems and A123Systems – will be able to deliver a production-ready battery in the near future."

The presentation of the E-Flex biodiesel variant is the latest step in GM's global efforts to diversify transportation away from petroleum and reduce CO2 emissions with a range of alternatives. These include:
  • The 2008 launch of the Opel/Vauxhall Corsa 1.3 CDTI, the premiere model in the ecoFLEX range of vehicles, which emits just 119 g/km of CO2.
  • Globally, GM is the leading producer of E85-capable biofuel vehicles, with more than 2 million on the road. This year, Saab will expand the availability of BioPower engines across its 9-3 and 9-5 portfolios, and E85 will be available on Cadillacs this autumn in Europe.
  • The introduction of eco-Turbo engines that offer lower consumption and CO2 emissions, with no trade-off in acceleration or top speed compared to the large-displacement engines they replace.
  • The introduction of the HydroGen 4 fuel cell vehicle and its inclusion in a global demonstration project to better understand the steps required to move hydrogen fuel cell vehicles toward commercialization.