Electric cars were central to the Renault booth at the 2010 Paris Motor Show, with the Zoe Preview and DeZir Preview concepts unveiled by CEO Carlos Ghosn.
DeZir is the first project involving Renault’s new Design Director Laurens van den Acker. The two-seater sports coupe has been designed to use the same basic drivetrain as that used by other Renault electric vehicles; the Kangoo ZE and Fluence ZE, which will enter production in the next 12 months and the Zoe Preview concept—a production version is due in 2012.
For the DeZir, power output is quoted as 110 kW with 226 N·m (167 lb·ft) of torque. The drive motor is mounted in a midrear position driven by a 24-kW·h lithium-ion battery pack located behind the bench seat that accommodates driver and passenger. Like the other Renault electric models, range is estimated at 160 km (100 mi).
Lightweight construction has been used for DeZir, which is fitted with a Kevlar body over a tubular steel frame—similar in construction to the Renault Megane Trophy racecar. Aluminum contrasts with the Kevlar and is used in the side panels, roof, and headlamp covers. The headlamps are prismatic with back lighting. The Renault logo on the front grille is also backlit.
Underbody fairings and a rear diffuser help to reduce aerodynamic drag, with Renault claiming a drag coefficient Cd figure of 0.25. Suspension detail includes a double wishbone arrangement, another feature shared with the Megane Trophy.
Like most electric cars, DeZir is equipped with regenerative braking. Recovered energy can be used by pressing a power boost button on the steering wheel.
The interior is trimmed mostly in white with white leather upholstery used for the seat, dashboard, and floor, contrasted with red lacquer on the center console. Renault says the interior styling is inspired by an amorous encounter. The white leather seat trim is apparently seared with lines of pulsing red light, suggestive, says Renault, of a beating heart.
Although Zoe Preview is also a concept, Renault’s Matthieu Tenenbaum, Deputy Program Director for Electric Vehicles, told AEI that the car on display represents a model that is around 90% ready for production. It will be produced in France and is scheduled for launch in mid-2012.
Although Zoe will share the same drivetrain as Renault Kangoo and Fluence ZE models, it is a purpose-built electric vehicle platform. So where the Fluence ZE has the batteries fitted in the trunk, necessitating it to be lengthened, compared with the internal-combustion engine powered Fluence, the steel monocoque of the Zoe was designed solely for electric power and the lithium-ion batteries are mounted under the floor.
The electric motor is rated at 60 kW with 222 N·m (164 lb·ft) of torque. Like other Renault electric vehicles, it is designed to be charged from a domestic power supply, taking six to eight hours to recharge from fully discharged. A fast charge for emergencies can supply an 80% charge in 30 minutes. The battery pack will also be exchangeable for a fully charged pack at a quick-drop exchange station. Schemes are currently planned for Denmark and Israel with partner Better Place.
Zoe is fitted with humidity sensors in the air-conditioning system to prevent dehydration on longer journeys. Passengers would be soothed by specially selected music from agency Creative Diffusion and light therapy from the central screen, said to stimulate occupants’ energy.
According to Tenenbaum, cooling was an unexpected issue for the Zoe design team. “You still have to cool an electric motor,” he explained. “But cooling is a function of the temperature difference between the motor and the ambient air. An electric motor runs at around 60°C, and for a conventional engine the coolant runs at around 90°C. Since the temperature difference is smaller for an electric motor, you need more air. At first, our designers thought they could close everything off, but you need the same air entrance at the front as a conventional car.”
Zoe uses a conventional steel monocoque construction. “What we have seen is that the weight of the car does not have so much impact on range,” said Tenenbaum. “Because we can recover a lot of energy in regenerative braking, so when you look at where you want to spend money to give more range, it’s better to put the money into a heat pump, for instance, instead of reducing weight.
Zoe will be fitted with a heat pump, as Tenenbaum explained: “It will basically limit the power consumption of auxiliaries such as interior cooling or heating systems. It will use small amounts of power, so it’s better for the range.”
Renault is also researching how to deal with low noise emissions, particularly where pedestrians are close by. The company is considering using parking sensors to trigger a sound alarm at speeds below 20 mph (32 km/h) to warn pedestrians of the car’s presence. “We are working with an institute in France on sound design,” said Tenenbaum. “But we are having to wait for regulations from Europe. There is a regulation in Japan for electric and hybrid cars, but in Europe it’s not clear for the moment what will be done.”