The RAC Green Grand Prix was held at Silverstone on 12 October and Green-Car-Guide took part.
The Green Grand Prix was a demonstration of techniques to improve eco-driving in some of the latest green cars, in advance of the RAC Future Car Challenge taking place between Brighton and London on Saturday 5 November 2011.
Members of the public, RAC patrol staff, and a selection of media took part in the Green Grand Prix. Laps of Silverstone’s Stowe circuit were driven in a range of electric, hybrid and conventionally-fuelled cars to see what levels of fuel economy could be extracted from each vehicle.
There were a number of interesting cars taking part in the Green Grand Prix. It was the first opportunity for most of the public and the RAC patrol staff to drive an electric car, and there was a rare opportunity for people to get behind the wheel of one car in particular, the Delta Motorsport E-4 Coupe. This car isn’t on sale, but it is a vehicle that has been developed as part of the Technology Strategy Board (TSB) EEMS Accelerate programme.
Each vehicle had to be driven to achieve maximum miles per gallon, or minimum energy usage in the case of the electric vehicles. However this wasn’t just a case of driving at a constant 30 mph around the circuit, as all vehicles had to reach 50 mph on the two straights.
To maximise the efficiency of your driving, it turned out that different tactics were required with each car. Our first ‘race’ was in the Delta Motorsport E-4 Coupe. This is a bespoke electric car designed from the ground up by Delta, a motorsport engineering company based at Silverstone. The battery-electric E-4 Coupe has a top speed of 150 mph and a range of 200 miles. It can also accelerate from zero to 60 mph in less than five seconds. It has a carbon composite chassis which weighs just 85 kg – two-thirds less than a comparable steel structure, despite being designed to pass EU crash tests.
The car features high performance direct-drive electric motors which produce over 120 hp each and over 600 Nm of torque, while only weighing 23 kg. The E-4 is designed around the low, floor-mounted batteries, it can seat four people, and it even has decent boot space.
Despite the Stowe circuit featuring a number of corners, including a sharp hairpin, the E4 Coupe could be driven around the entire track without applying the brakes. And the brake regeneration system was switched off for the event, so there was no additional slowing under deceleration. This exercise proved that the Delta has excellent handling, with the car feeling extremely stable and secure through the corners. The 50 mph speed had to be reached at the optimum point on the straights to strike the right balance between careful acceleration and not entering the corner at the end of the straight too quickly.
Next up was a drive in the Peugeot 508. With a diesel engine, this was the only conventionally-powered car in the event. However it features an e-HDi stop and start system, returning 109 g/km CO 2
– although the stop and start didn’t help us much on the race track. Even so, we achieved 61.8 mpg on our drive around the circuit, which is not bad over a short, twisty course.
Our final drive was in a Peugeot 3008 Hybrid4 , the world’s first-ever diesel hybrid. We had recently driven this car on its European launch and we awarded it a 10 out of 10 Green-Car-Guide rating. So we were intrigued to see how the car would perform on the track.
The 3008 was able to start off in ZEV or electric mode only, and the trick was to drive in a way that kept the car in electric mode for as much of the time as possible. This would have been helped if the hybrid battery had been fully charged when we started driving the car, but it only had one bar out of six on the battery charge indicator – presumably because everyone else was trying to drive it exclusively in electric-only mode, to eke the maximum miles per gallon out of the car.
So it wasn’t long before the diesel engine had to kick in to sustain the battery charge. The one thing about the 3008 that was evident on the track, that we didn’t notice as much on the launch, was the brake regeneration. This system recaptures the energy that would otherwise be lost when braking and uses it to recharge the battery. It did this very effectively and it wasn’t long before we had 3 bars showing that our hybrid battery was half-charged. The other outcome of this was that the brake energy recuperation was highly effective in slowing the car, so you could accelerate very gently and reach the required 50 mph just before the corners, and the car would slow itself whilst recharging itself at the same time. All this clever technology meant that we also achieved 58.7 mpg in the 3008.
There was also a non-hybrid 3008 diesel available for drives. This car featured ‘Grip Control’ – Peugeot claims that this gives the front-wheel drive 3008 similar levels of ability in the snow to a higher emitting four-wheel drive vehicle.
Although we appeared to be achieving some of the highest miles per gallon figures on the track, there was also a driving simulator, and our performance on this was less impressive. We obviously spend too much time driving real cars on real roads and too little time playing computer games, as our record of crashing the car on the simulator was better than our fuel economy record.
The eventual ‘general public’ winner of the Green Grand Prix was Scott Penny, from Woking. An RAC member, Scott entered for the competition online, and it was the first time he had ever driven an alternative-fuelled car. His normal everyday mode of transport is a Mazda RX-8 so it’s perhaps no surprise that he particularly enjoyed taking the Delta E-4 Coupe around the track.
The day of eco driving proved that we could achieve an average of over 60 mpg from two family-sized Peugeots thanks to a light right foot and by taking the correct racing lines around corners. Avoiding braking means that you also avoid having to accelerate again – which is the time when you really burn through your fuel. Although you’re likely to have to brake on real roads more than you would on a track, you can minimise the amount of time you brake by looking ahead and planning your driving more thoughtfully – in other words, all the established techniques of advanced driving. Making sure that your car has the correct tyre pressures and ditching any unnecessary weight from the vehicle also makes a big difference.
The RAC Future Car Challenge event takes place between Brighton and London on Saturday 5 November 2011. Green-Car-Guide will be piloting an electric BMW ActiveE in the event. The aim of the challenge is to drive 60 miles from Brighton to London using the least energy possible within the 2 hrs 45 min minimum and 3 hrs 30 min maximum time permitted. Imperial College London will monitor the energy usage using data-loggers which will measure fuel consumption and CO 2
emissions, or current and voltage (in the case of electric vehicles).
The formal finish of the event will be in Pall Mall followed by a special ceremonial finish and presentation in Regent Street. Here, the vehicles will join the display of around 100 pre-1905 motor cars in the London to Brighton Veteran Car Run International Concours in front of an audience of an estimated 250,000 people.
For more information see:
Other cars that took part in the Green Grand Prix:
The electric Mitsubishi i-MiEV has been around for a while. It’s based on a petrol car rather than being a clean-sheet electric design. It’s almost as refined to drive as the all-electric Nissan LEAF, but it’s smaller; its narrow width makes it great for driving in urban areas, but not as ideal for family use. However it can still seat four people, can reach 81 mph, and has a range of 93 miles. It’s priced at £23,990 (after the £5,000 government electric car grant).
The smart fortwo looks like it should have been an electric car from the start. Its miniature size mates well with an electric powertrain – in our view it’s better to drive than the petrol and diesel-powered versions with their frustrating semi-automatic gearboxes. The fortwo ed has been around as a trial for over two years, with 100 cars leased to a very limited audience. The ed can travel up to 72 miles between charges, which typically take around 8 hours for a full charge. It achieves the equivalent of 300 mpg and has an electronically-limited top speed of 60 mph. The smart fortwo ed is fine for city use, but it doesn’t have the performance or range to drive it far outside of city limits.
The Toyota Prius is seen as the original hybrid, offering low emissions of 89 g/km CO 2
and excellent economy of 72.4 mpg in a decent-sized family hatchback thanks to its full petrol-electric hybrid system.
The Toyota Auris Hybrid offers hybrid technology in a smaller package than a Prius. The result is 74.3 mpg and 89 g/km CO 2
for models with 15-inch wheels, or 70.6 mpg and 93 g/km and for versions with 17-inch wheels.