After one year of preparation the TUfast Eco Team achieved their goal: On Saturday, July 16 2016 their world record team undertook the official world record attempt and set a new high mark for vehicle efficiency. The team started at the break of dawn to prepare everything in time at the test track that long-standing sponsor Audi had reserved. Last tests done on the previous day had them hoping for a good chance at reaching their own goal of 1000km/kWh.
As vehicle for the world record attempt the team chose eLi14, which they had built for the 2014 season. They saw it as the ideal candidate because it has aerodynamic advantages to more current models (which are built to a newer version of the Shell Eco Marathon competition rules) but it is still very light and has a flexible running gear train. Based on experiences with eLi15 and eLi16 they tuned up eLi14. The custom-built motor controller with optimised acceleration and speed simulation, new rims with extremely low friction bearing, a motor with optimised magnet placement and silver wire coils for reduced ohmic losses and an aerodynamically optimised top cover without solar cells were all fitted into eLi14.
The track was inspected and the vehicle was thoroughly checked over by the judges from Guinness World Records as well as Professor Herzog of Technical University Munich and Manfred Schedl of TQ Systems / Robodrive. Gently eLi14 accelerated to the preset speed to cover the necessary distance of 25 km/h within one hour. This average speed thus complies with that of the Shell Eco-marathon.
60 tense minutes followed - any technical problem, however small, could have cost precious time. But eLi14 completed lap for lap with constant timing and despite turning off the motor early rolled almost a kilometer past the finish line. They received the first result: 1142 km/kWh. The conservative first run had to be improved and at once the team modified the speed control, changed the rear tire and increased tire pressure. The acceleration profile was also redone and the team calculated a new earlier motor shutoff point based on the vehicle's glide.
The second run completed without any hitches and despite stronger wind was a significant improvement. The final result: 81.16 Wh/100km, equivalent to 1232 km/kWh or 10956 km per litre of 95 octane gasoline (by caloric value). In units more familiar to motorists that is about 0.009l per 100km or, for the United States, 26135mpg.
The team proudly received the Guinness World Record certificate and now proudly hold the title of "most efficient electric vehicle".
IDTechEx comment: Now let's see this combined with extending solar panels and wind turbine for when it is parked and we have a formidable robot Energy Independent Vehicle EIV for a host of tasks. For more see the IDTechEx reports on High Power Energy Harvesting, on Robotics and on Energy Independent Vehicles.
Source and top image: TUfast
Learn more at the next leading event on the topic: Energy Independent Electric Vehicles 2017 on 27 - 28 Sep 2017 in TU Delft, Delft, Netherlands hosted by IDTechEx.