The Formulec EF01 is an electric Formula 1 racing car which is claimed to be the fastest electric car in the world. Designed and created by Formulec and its technology partner Segula Technologies, it is capable of accelerating from 0-100 km/h in three seconds flat and has a top speed in excess of 250 km/h.
With sponsorship from France’s FCI, the EF01 is being shown during the 2011 international motor racing season as an opening highlight at a number of top motorsport events. In 2012 the first electric single-seater race series will be established. This will be called the Formulec World Series and will comprise 10 events across five continents. South Africa will host one of the races.
The format will continue in 2013, allowing selected top class international drivers to measure their skills at the wheel of the EF01 on race tracks around the world. The vision for the 2014 season and beyond is for the Formulec World Championship to be created. Heralding a new era in racing, the EF01 is an aggressive and exciting vehicle. It has been tested on the Bugatti track in Le Mans by Alexandre Premat, and has proved that energy efficiency is now a reality in racing.
The system has an output power of 176 kW, corresponding to an efficiency of 98%. By contrast, conventional combustion engines have a thermo-dynamic efficiency of only about 30%, the remaining energy being lost as waste heat. Looking at the functional chain from the source of energy to its consumption (the well-to-wheel value), electric cars achieve a value of over 70%, whereas the value for combustion engines barely exceeds 20%.
Many technological innovations were used in designing this car, with priorities being a highly compact and integrated architecture and optimised battery distribution. To achieve this level of performance, Formulec counted on some world class technical partners. The energy to race for 20 to 25 minutes is stored in lithium ion batteries from French company Saft. The drivetrain is from Siemens. The key technology is a special interconnection system that relies on FCI’s high performance connectors, which are recognised for their compact size and low weight. FCI has one of the smallest solutions for the high current and high voltage DC connection (250 A/400-800 V) needed for the battery, junction box and inverter.
The drivetrain encompasses the electric motor; the inverter, which converts the direct current from the battery into three-phase alternating current; and control units. The car needed a powerful, light and compact motor. To achieve this, Siemens researchers coupled two engines, each with a peak output of 125 kW. Since the power input is limited by the battery, a total of 176 kW is actually available for driving purposes. Each of the two motors weighs 52 kg, resulting in a power density of 1,7 kW/kg.
The gears for the twin motor are changed by a central two-speed transmission. This is unusual because electric cars have a high torque across the entire rpm range and can generally accelerate to their top speeds without needing gear changes or even a transmission. However, on racetracks with very tight curves, such as the Circuit de Monaco, drivers have to temporarily reduce the vehicle’s speed so much that it is advisable to change gears by means of a rocker switch.
In first gear, the EF01 twin motor accelerates the car from 0 to 100 km/h in three seconds, while in second gear it can achieve speeds of up to 250 km/h. To keep the interruption of the tractive force at the wheels as short as possible, the car’s specifications stipulated that gear changes must take place particularly quickly. Shifting takes place in an incredible 150 ms in the Electric Formula car. A highly precise control system is needed in order to achieve this on a clutchless transmission.
For more information visit www.formulec.com
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