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Vauxhall Ampera – the electric car powered by petrol

This is the future of cars according to Vauxhall. The Ampera is an electric car, but with a petrol engine to power the electric motor when the battery runs low.

Yes, that’s right, it’s an electric car powered by petrol. It’s known as an ‘E-REV’ – an ‘Extended-Range Electric Vehicle’. It has a petrol engine (or a ‘range extender’) under the bonnet – together with an electric motor. Under the centre of the car and between the rear wheels, is a large t-shaped battery – the heart of the Ampera.

Vauxhall Ampera
This is how it works. You plug the car in to your household electric socket and recharge it. Just three hours will give the battery a full charge which will take you around 40 miles. That, according to GM’s figures, should be enough for most people most of the time, as 80% of journeys are less than 30 miles per day. You can then recharge the car again at your ‘home fuel station’ and use it as an electric vehicle once more.

If you need to drive from London to Scotland, unlike with normal electric cars, you can do this, as the 1.4 litre 4-cylinder petrol engine kicks in when the battery drops to 20% of its full charge. The 20% limit is due to damage occurring to the batteries when they regularly drop below this 20% charge level.

‘Extended range’ driving should provide a range of over 300 miles. If the car is faced with a hill when the petrol engine is in use, extra power can be taken from the battery. However the petrol engine does not recharge the battery. Vauxhall is comfortable with this engineering decision, as they say it’s far more efficient for the National Grid to charge the battery.

Why a petrol engine rather than a diesel? Petrol engines are smaller, lighter and cheaper. And the engine can also run on E85 bioethanol biofuel.

Note that unlike today’s hybrids, Vauxhall is using the 80hp petrol engine to run the electric motor rather than to power the wheels directly. The electric motor runs at 98% efficiency, whereas a petrol engine runs at 35% efficiency due to issues such as heat losses.

It’s interesting to note that the petrol engine does not run at variable speeds; it runs at a constant two-thirds load at all times, which is its most efficient state.

The concept behind the Ampera means that it displays the characteristics of an electric car at all times when driving – complete with full torque from the start of acceleration. The Ampera reaches 60mph in around 9 seconds, with a top speed of 100mph. The styling is influenced by aerodynamic considerations in order to ensure maximum efficiency.

Other innovations include minimal energy draw, including interior heating that runs from the electrics – meaning that the car interior can be warmed up by a remote control from the house.

The benefits are that the Ampera should emit an average of less than 40g/km CO2, over the current European test cycle, yet the five door hatchback can carry four people and their luggage without the ‘range anxiety’ associated with most electric vehicles. Of course in purely electric mode, theoretically the CO2 emissions should be zero if recharged with renewable electricity – which will be increasingly likely in the future as new developments such as the Round 3 offshore windfarms come on stream.

However the Ampera will still have the same problem as other electric cars if the owner doesn’t have secure off road parking or a garage – there’s no way to recharge until more on-street recharging points appear. The Ampera will still work if it has petrol in its tank, but that’s hardly using its technology to its full potential. The plan is for more recharging points to appear; even a 40 minute charge at a supermarket would help to inject some power into the battery.

The Ampera has ‘Voltec’ technology, which uses lithium-ion batteries, but the 200 cells are different to most lithium-ion technologies in cars today. Lots of work has been done to ensure safety in crash tests, as well as to ensure that the cells don’t overheat. Vauxhall claims that the Ampera is designed to last for 160,000 miles, or 10 years.

Will it be priced like a family saloon? Probably not. More work needs to be done on the pricing, and talks with government about incentives need to happen first.

However based on current fuel prices, Vauxhall predicts that the Ampera will cost roughly one-fifth of the current cost per mile of an equivalent petrol-engined car.

The Ampera is due to be here in the UK in 2012. The Opel version will be available in Europe in 2011. That means GM will be first to market with this technology.

What’s the next future technology for GM after E-REV? Hydrogen. Find out more next week.