The Geec at Shell Eco-marathon Europe 2018: Monday to Friday
We started in September 2017 when this Geec team came together. Some members were veterans of several years, and others were new. We inherited the 2017 car and spent the year making it better: brakes, drivetrain, electronics, chassis, body. After 5 years of development, the Geec has moved into a regime where improvements are harder and harder to find.
How it works
We arrived in Queen Elizabeth Olympic Park, London, on 1st and 2nd July for Shell Eco-marathon 2018. This is truly an Olympics of engineering. 140 teams of students are gathered here from Europe and Africa. Every team has built an Urban Concept car (practical city car, with 4 wheels, lights and wipers, and an upright seat) or a Prototype (unrestricted rules for maximum efficiency, typically 3 wheels, with the driver lying flat). They race over a 14.55 km course; the winner is not the fastest car, but the one that uses the least energy. Speed doesn’t matter as long as the average is over 25 km/h. Teams compete in categories according to their energy source – battery-electric, hydrogen fuel cell, or internal combustion (gasoline, diesel, ethanol, or biofuel). The Geec is a battery-electric prototype.
Races are organised like F1 qualifying sessions. We’re not racing head-to-head with other cars, but we share the track with them. Our drivers seek out the best lines and jockey for position with rivals in a dynamic game of chess. They use the accelerator as little as they can, and the brakes only if they have to. Race organisers have our car instrumented to monitor energy draw from the battery, and they give us a score in kilometres per kilowatt-hour (km/kWhr) after every run. Every team gets up to 4 attempts over 3 days, and only the highest of our 4 attempts will count in the final reckoning. The team with the biggest score takes the trophy home, and that’s all.
We came, we saw, we got the car ready to race. We arranged our tools in our little garage in sector E of the tent village and spent a few days getting ready for the dreaded technical inspection. We have to convince scrutineers that the car complies with competition rules for safety and fair play. Can the driver escape the car in an emergency? Are the electrics robust? Can the brakes actually, you know, stop the car? Actually, yes. Apart from a small adjustment needed on the internal wheel-guards, we had the smoothest passage through inspection in the Geec’s 4-year SEM history. We get the precious stickers to show we’ve earned a place on track, and cleared the first obstacle.
Our first opportunity to race would be on Friday afternoon. On Friday morning, we got a surprise visit to the garage: judges for the Technical Innovation Award, an off-track award “presented to the team which demonstrates outstanding technical ingenuity along with optimal use of new materials, components and inventions.” Aerodynamics team leader Tom Dillon had discovered that wheels, and the holes in around them in the bodywork, can account for nearly half of aerodynamic drag on our car. For the back wheels, it’s easy enough to reduce this problem by closing the bodywork down to a narrow slot wheel. But the front wheels have to move to steer the car. Tom invented an ingenious aerodynamic seal that revolves with the steering mechanism to minimise the hole in the bodywork. On the back of this, we were shortlisted for the innovation award. Let’s spell it out: out of 200-odd teams, we are on a short list for an award. Hence the name. Shortlist. We’ll find out where this is going at the awards ceremony on Sunday!
Moment of truth
Friday afternoon comes around slowly. Prototype teams queue for hours for a slot on the start line. London is baking: we measure the temperature of the ground at 50°C. The inside of the car is at 32°C before it’s closed up with a human and a live motor inside. Finally, the Geec rolls to the start line with Laura strapped in. The moment of truth. The green flag waves.
And then, the Geec is on track, ticking off the laps. But all is not well. We need average lap times no more than 2 minutes 20 seconds to make the required 25 km/h average, but the first laps are 2:20 to 2:40. Laura, in contact with Tom H and Niamh in mission control, claws back the time deficit, lap by lap. She sprints across the finishing line just 5 seconds inside the 35 minutes allowed. We have a valid run.
The hardest 99% of the campaign is over, and we’re at the races. We have a score safely on the board, and from here on we can fine-tune and take some risks. The score comes in at 286 km/kWh, putting us in 10th place of 36 battery-electric prototype teams. Not too bad, but we know there’s room for improvement. Laura had to use power almost constantly to make up time, though we should need it only for short bursts between long freewheeling glides. That’s not good for efficiency. We start to analyse, debate and plan. Three runs to go.