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GM Unveils Opel Flextreme: Plug-in Diesel Hybrid Variant of E-Flex

The Opel Flextreme.

GM has unveiled the third variant of its E-Flex electric vehicle architecture in Frankfurt. (Earlier post.) The Opel Flextreme is a plug-in diesel series hybrid that offers up to 55 km (34 miles) of all-electric range. A 1.3-liter turbodiesel powers an onboard generator to replenish the 16 kWh li-ion battery pack and extend the vehicle’s driving range to a total of 715 km (444 miles).

Based on the current European test procedure ECE R101 for range extender vehicles, GM expects the Flextreme to emit less than 40 g CO2/km in combustion mode.

X-ray view of the Flextreme powertrain. Click to enlarge.

The electric traction system delivers 120 kW maximum electrical and mechanical power, with continuous mechanical power of 40 kW. The four-cylinder 1.3-liter CDTI engine produces 53 kW peak power output. The car accelerates from 0-100km/h in around 9.5 seconds and has a top speed of around 160 km/h (99 mph).

High-speed piezo sensors integrated in the glow plugs measure the pressure in the cylinder, so the injections can be matched to the actual combustion in real time. The 1.3-liter four-cylinder engine is the second unit from GM to feature this system, after the 2.9-liter V6 engine displayed at the Geneva Motor Show. (Earlier post.)

The lithium-ion (nanophosphate) battery pack has peak power of 136 kW and voltage of 320 to 350V. The Flextreme can be charged in around three hours via a standard 220 V electrical socket.

Opel packaged two Segway electric personal transporters packaged below the cargo floor of the Flextreme. The Segways can be used in areas that cars cannot enter, thereby adding an extra mobility option. The electric two-wheelers provide up to 38 km (23 miles) of range.

General Motors introduced two other E-Flex variants earlier this year:

  • At the Detroit Motor Show in January 2007, the Chevrolet Volt debuted with a 1.0-liter three-cylinder turbo gasoline engine designed to operate on gasoline or E85, a mixture of 85 percent ethanol and 15 percent gasoline. (Earlier post.)

  • At the Shanghai Motor Show in April 2007, GM presented the Chevrolet Volt with enhanced hydrogen fuel cell propulsion. With four kilograms of hydrogen on board,the fuel-cell powered Volt has a range of up to 480 kilometers. (Earlier post.)



It's good to see GM stirring about. In the distant past they achieved a measure of greatness as a result of imagination and innovation.

This offering is certainly a step in the right direction.

All it needs is 4-wheel in-wheel drive.


An E85 hybrid would be an amazing combo.

I have to say though that I'm sick of all the "show cars". One production hybrid would do more for GM than 2000 show concepts.

Max Reid

Dec-2007 : 2 Hybrid SUV's are coming from GM. I dont know how the Hybrid-SUV's will be received.

Yes, GM have to bring a Hybrid small car which gives around 40-45 MPG.

As for the Plugins, even a car with 10 mile range coming to market should be good.


Adding to my comment below, sorry I left off my name, this is the right direction. A nice diesel hybrid.

Lou Grinzo

The other day I slammed the Mitsu i-Miev for being ugly.

The Flextreme is a perfect example of how attractive a small car can be. Well done, designers.


Very nice. Minor question: What does one call this...a car, a crossover, a hatchback, a minivan? I was leaning towards "car", but not really sure.

Does anyone know why the range is slightly less than the Volt's? Is it because it's heavier?--just wondering.

Rafael Seidl

I strongly advise you take any MPG / CO2 claims for any PHEV with a large grain of salt. There's lies, damn lies and then there's marketing. So ask, ask and ask again *exactly* how vendors obtained the fuel economy/CO2 emissions numbers for their PHEV concepts. Unlike those in California, official EU fuel economy procedures are still hopelessly ill-equipped to deal correctly with hybrids, never mind PHEVs. There is ample scope for sleight of hand.

First, the manufacturer may be counting only the on-board fuel consumed to compute the CO2 emissions your driving will cause, based on some arbitrary total trip length. As you know, grid electricity is produced by elves and fairies. Coal, natural gas and nuclear have nothing to do with it.

Second, the portion driven on grid electricity may have been maximized for marketing purposes by starting with a fully charged battery and deep discharging it. Such abuse will severely shorten its life expectancy. Unless you want to buy a shiny new battery pack every other year, real-world range on grid electricity will almost certainly have to be less than what is claimed.

A credible marketing story would indicate range on grid electricity alone assuming e.g. 10 year/150.000 mile life expectancy (whichever comes first). Also, it would detail miles per kWh for the official duty cycle when driven as much as possible on grid electricity alone and separately, when driven on the ICE alone. The official duty cycles cover defined distances, so with a little math you can use this data to compute miles per kWh as a function of total trip length, assuming the official drive cycle just repeats.

Of course, marketing types want to persuade you that their shiny and no doubt very expensive PHEV is "better" in some way than a conventional car and, worth the premium. So, they thow out some suitably eye-popping MPG number, hoping that you'll be too stunned to ask any questions. As they say in Germany: know your Pappenheimers.


@ Lucus:

Electric drive in wheel technology has a down side, especially when used on cars on the steering wheels. Many race cars design the tires, wheels, brakes and suspensions to be as light as possible to dampen and suppress the rebound of the tires on bumps and in turns. The idea is to keep the tire in contact with the road surface at all times by reducing the unsprung weight. The Tesla roaster only drives the rear wheels and then from the center of the rear axles. Additionally, Locating the electric motor at the wheels subjects them a lot of abuse from water, mud, sand rock, etc. and begs the idea of encapsulation.


Rafael nails it.

But can you explain the "know your Pappenheimers" thing?


Possibly the best design showing more green ingenuity with the capable Segway traveling along for more enjoyment and less energy expelled once you reach your destination. Now all they need to include is the ability to charge the Segway's from the vehicle while you travel to your destination.


its fantastic !

what a wonderful car


I agree the car is attractive. It is sleek and futuristic looking. It looks sporty and oozes techno. It looks like it could be a variation of the Toyota Hybrid X concept car. The similarities are unmistakable with the shape, the sleekness, the open design, the extensive use of glass, right down to the rear passenger suicide doors.

What I find curious is that people describe this as attractive but rag on the Hybrid X as ugly. I get the impression that if the company logos were swapped so would the opinions.

Richard C

Funny, no release dates are ever included in the GM autoshow fairy tales.


@ jack :

When Germans say "Ich kenne meine Pappenheimer" it means they know very well the way some people behave (Pappenheim is a city, a "Pappenheimer" is an inhabitant of this city). Rafael was of course referring to the marketing guys. According to Wikipedia here is the origin of this colloquialism (see "Legacy") :

Max Reid

Time for GM to put the 2-Mode Hybrid in car soon.
Benz showcased Hybrid S-300 with V4 Diesel engine.

Today Oil prices have set a record closing price of $77.49 (earlier high was $77.03 a month ago).

Time for market to move into Hybrids, otherwise everyone will be losing the market share.

Rafael Seidl

@ Jack -

"I know my Pappenheimers" is based on a quote from Schiller's "Death of Wallenstein", set in the Thirty Years War. In it, a loyal cavalry detachment from the city of Pappenheim arrives to ask Wallenstein if rumors of negotiation with Sweden are true.

Today, this popular German ideom has a very different meaning, roughly "I know a bull#### artist when I see one."


The problem is we have no standard way of assessing PHEvs.
There are many good ideas here - small displacement diesel engine used as a generator for instance.
Personally I would leave the segways behind - what were they smoking when they came up with that ?

So we need a PHEV test - perhaps some of the good people of this blog could suggest one - but it is very tricky due to the mix of short and long runs, and the frequency of charging.

For the carbon content of the electric power, you could just use the European or US average and leave it at that.

Then just measure (say) a set of journeys as follows:

3x 10 miles, 3 x 20 miles, 3 x 40 miles, 3 x 80 miles, 3 x 160 miles.

[ or equivalent in KM ]

And average it, or provide the average of the 10+20s and the 80+ 160s as well as the global average.

A good test could sort out a lot of arm waving.

Then you have cost - of the vehicle and battery replacement.

Again, you might be better with a stop/start system which is cheap enough that people can actually buy it - and people can sell it at a profit.

We are basically waiting for the right batteries, or as Beckett put it - waiting for Litho.

Big Fan

BMW_4_ever, good point about concept cars. What in the hell is the point of showing a car that will never see the light of day?



I use to buy computer equipment for a company and I wore a tie that had a very nice design down the middle. When I would listen to a sale presentation and I didn't believe all I hear I would turn the tie sideways so the salesman could read that the design read "Bulls..t." I didn't show it to anyone else but the salesman but I observed that over time the word was out and very few of them made statements they couldn't back up.


Seem like this car is more Baron Munchausen than Gottfried zu Pappenheim.


PHEV fuel economy could be listed as follows:

50km + 5.7l/100km or
30miles + 40mpg

Where the first figure is the all-electric range down to 30% of battery capacity (a distance that doesn't put undue wear and tear on the battery). The second number would be the standard mileage of the car based on HEV operations.

@ Rafael:

"the portion driven on grid electricity may have been maximized for marketing purposes by starting with a fully charged battery and deep discharging it. Such abuse will severely shorten its life expectancy. Unless you want to buy a shiny new battery pack every other year, real-world range on grid electricity will almost certainly have to be less than what is claimed."

I know I'm coming across as a total GM/PHEV fanboy in my posts, but the stuff that has been leaked so far indicates that GM's system only discharges the 16kWh pack to 50%DOD. So if 8kWh is sufficient for 34-40 miles, let's do the math:

40/8= 5 miles per kWh for the Volt concept
34/8= 4.25 miles per kWh for the Flexstreme

If you look at Volvo's projected 62 mile range for the ReCharge 12kWh pack:

62/12=5.16 miles per kWh

Now let's compare that with some real world data from pure EVs:

The gen2 NiMH EV1 got 150 miles max with a 26.4kWh pack:

150/26.4=5.68 miles per kWh

The Tesla roadster gets 200 miles with a *really* heavy 990 pound 53kWh pack:

200/53=3.77 miles per kWh

The manufacturers all seem to be using roughly the same efficiency formulas, so the 34-40 mile range at 50% DOD really doesn't seem too far fetched. Using only partial discharges will help extend battery life, but then there's also the cost and weight issue. However, if the pack lives up to A123's claim that it will do 7000 cycles under *optimum* conditions, that's still a distance of...7000*34= 238,000 miles.


Sorry, last comment was mine. Forgot to sign it.


How often do concepts live up to their initial claims? How often do a combination of claims come to fruition?


Not bad. Build it.

Lose the segways and get that 0 to 60 time up.

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