Renault Electric Car Uses Energy Wisely, Maximizes Range

Alternators spun by gasoline or diesel engines can produce lots of electrical power for a vehicle’s lights, on-board computers, entertainment centers, climate control systems, and more with very little impact on the distance a vehicle can travel between fill-ups. In battery electric vehicles, though, these electrical accessories compete for the electric power needed by the traction motor and supplied by the battery. Thus, their use can significantly reduce vehicle range. Aerodynamic drag, rolling resistance and other parasitic losses – important in all vehicles – are even more critical in EVs.

Minimizing energy consumption was a key goal in designing Renault’s Z.E. Concept. The Z.E. (‘Zero Emission’) is based on the new Renault Kangoo be bop. The 13-foot long urban car is propelled by a 95 horsepower (peak) electric motor powered by lithium-ion batteries. Performance parameters and driving range are not identified.

Several innovative features are incorporated to minimize the heating and cooling load on the electrically powered HVAC (heating, ventilation and air conditioning) system. The bodywork uses two insulating panels with a sandwich of air between them, much like a Thermos bottle. Air – a very effective insulator – limits variations in temperature between the exterior and interior of the vehicle.

Heat-reflective paint used on large surface areas and acid green-tinted glass helps reduce temperature fluctuations. The temperature regulation system is powered by roof-mounted solar panels. All this adds up to a pleasant interior even when the car is parked, avoiding the necessity to always switch on the climate control when starting the vehicle.

The interior temperature is maintained at 59 degrees F, but warmer air is directed at the head, hands, and feet. That’s because the impression of heat is especially felt on the face and hands. Accordingly, warmth can be channeled as close as possible to key zones, such as through a heated steering wheel, so occupants feel comfortable while using less electrical energy.

Aerodynamic drag is reduced by replacing conventional side view mirrors with streamlined, low-energy cameras that are also powered by the roof-mounted solar panels. Low-drag, full disc aluminum alloy wheels also improve aerodynamic performance while Michelin Pilot Sport PS2 tires reduce rolling resistance.

The headlamps use efficient, high-performance light-emitting diodes (LEDs) that not only last longer, but also use much less electrical energy. A linear display on the outside of the door shows how much driving range remains even before a driver gets into the vehicle. A mobile phone-based navigation system is used to eliminate the need for an energy-consuming onboard computer.

Electric power is further conserved by Man Machine Interfaces that help pinpoint the nearest charging stations as a function of the remaining range. When things get really congested, an electric scooter, charged by the car’s battery, can be easily unloaded from the vehicle’s trunk.

Finally, the Z.E. Concept contains very few fluids that need recycling at the end of the car’s lifecycle, and its pedestrian-friendly, polyurethane gel bumpers deform easily to soak up minor knocks. All in all, this is one eco-friendly concept that’s in tune with the times.