Overview: Vauxhall Flextreme GT/E Concept show car
The Flextreme GT/E sets out to illustrate how extended-range electric vehicle (E-REV) technology can be plugged into large or mid-sized vehicles, as well as compact cars like the upcoming Ampera. E-REV is Vauxhall’s name for a series hybrid vehicle, in which motive power is provided by an electric motor, while a combustion engine acts as a generator when needed to extend the car’s operating range. Vauxhall intends to adapt this methodology to passenger cars of all sizes and market segments. The Flextreme’s motor is fed from a T-shaped lithium-ion battery pack located under the floor and rear seat.
In good show car tradition, the Flextreme is visually striking. Long and low, it abandons modern upright packaging in the interest of reducing the car’s frontal area. The payoff is an overall length of over 4.7m. A Cd value of 0.22 is quoted, along with a commensurately impressive maximum speed of 125mph. The underbody is panelled for smoothness and sweeps up towards the rear with a venturi-like profile to reduce drag. Relatively narrow 195-section tyres are fitted to keep the frontal area down.
The Flextreme also explores the potential for active shape shifting. At speeds above 30mph, a vertical panel extends along the body from the air extraction slot behind each rear wheel-arch. These 350mm-long side spoilers guide the airflow around the rear corners of the car, reducing turbulence. The roof features a fixed glass panel whose transparency is adaptive: sunlight is admitted to warm the interior in cold weather, but the panel darkens for coolness in the summer.
To control weight, carbon composite outer panels are used, along with polycarbonate window glazing and aluminum alloy structural components. Compared with conventional materials, these offer a 40 per cent. weight saving.
Vauxhall’s E-REV series hybrid drive system has been seen before, being developed for the forthcoming Ampera. Despite its greater size and a maximum speed of more than 125mph, the Flextreme GT/E is estimated to offer performance similar to that of the Ampera: a battery-powered driving range of up to 40 miles and a total range of over 300 miles. Vauxhall estimates that the car will turn in fuel consumption figures around 175mpg, with CO2 emissions of less than 40g/km.
The Flextreme’s electric motor delivers a substantial 370Nm, delivering more than adequate standing start acceleration: Vauxhall estimates that the 0-100km/h sprint will take less than nine seconds.
Vauxhall describes the Flextreme as a logical next step towards an emerging strategy for the electrification of the car, which will in time include products using battery, serial hybrid, serial-parallel hybrid and fuel cell technologies.