Racing as slowly as possible

Around the world on a full tank, or to Madrid and back on a litre of petrol – it is always the same teams who achieve astronomical scores during the Shell Eco-marathon, an annual contest for economic driving. What are their secrets?

Petrol and diesel fumes drift upwards from a long line of vehicles to a cacophony of banging and clattering. Dozens of cars are lined up at the starting line. Some are as streamlined as a rocket, the only uneven surfaces being formed by the sponsors’ stickers. Others appear to be held together with duct tape. Everywhere there are students darting about, carrying bicycle pumps, small fuel tanks, and screwdrivers. They continue to tinker about on their vehicles up to the very last moment.

It is Saturday 23 May, the third and penultimate race day for the Prototype vehicles. These are futuristic looking cigar-shaped cars that are hardly any wider than a human body. The drivers weigh around fifty kilos and take part in the race lying down. The goal is to cover sixteen kilometres in nine circuits of a special track around Ahoy Rotterdam while using as little fuel as possible. Earlier in the day, other teams raced using more conventional vehicles that allow you to get in and out in a normal fashion – the UrbanConcept cars.

The first ‘cigars’ set off to wild cheering among the spectators. The electric cars start moving without a sound. Meanwhile, the fuel-powered vehicles make a deafening racket, like highly tuned mopeds. They accelerate, and after a few seconds allow the car to roll out for hundreds of metres, assisted by a flywheel that is connected to the engine.

Ideal line

The students of the Delft Ecorunner team are nowhere to be seen. They have sought refuge in their pit box; it is a miserable and windy day. Some students keep a close eye on the weather forecast on a laptop. Others tinker around with the suspension of the Ecorunner V.

The activity outside the tent does not appear to put the Delft students off. Should the Ecorunner not be lining up as well? “No,” says Rowenna Wijlens, a second-year Aerospace Engineering student. “It’s now quite windy. We are waiting for the weather to improve. It’s also better to be among the last to start, just before the track closes. That way, the other vehicles are not so much of a hindrance and you have the best possible chance of following the ideal line.”

It’s a question of lining up at the right time, and that suits the Ecorunner team just fine. On the second day, they chalk up a score of 1170.4 kilometres per cubic metre of hydrogen. Converted to the energy content, that is 3519 kilometres to a litre of petrol. This puts the TU Delft students at the head of the hydrogen classification.

It is important to drive strategically, but of course the vehicle has to be in tip-top shape as well. What are the secrets of the Delft students in terms of technology? “We have the world’s most aerodynamic car,” says Rick Settels, the PR man of the Ecorunners and a third-year Mechanical Engineering student. “It has a resistance coefficient of 0.0512, making it more streamlined than the latest Nuna solar-powered car. We will soon be roaring into action.”

Team member Luc van den Ende adds: “In this competition, reducing the rolling resistance makes no difference, because everyone uses the same tyres. It means the design of the body is what determines who wins. And that is what we are really good at.”

The degree to which the Ecorunner team had tightened up the design was evident earlier in the afternoon between the rounds of the competition in the paddock. During the first test drive, the steering angle of the front wheels was not optimally aligned. It was a matter of a few millimetres. The design was also adjusted to the weight of the driver. Van den Ende: “When the driver lies down in the car, the body drops half a centimetre. When we discovered that, we were able to further optimise the position of the wheels.”

La Joliverie

Back to the line-up. Here, school students from one of the most renowned teams of the Shell Eco-marathon are busy working on their car. Team Microjoule La Joliverie are happy to let the procession of competitor cars drive by. Like the students from TU Delft, they are waiting for the weather to improve. “There is not enough sun,” says school student Kévin Paillard. “When the track is a bit warmer, the wheels will encounter less rolling resistance.”

Dozens of boys from the Lycée Saint-Joseph La Joliverie private school have travelled to Rotterdam in the proverbial wake of their Microjoule car, which is as smooth as glass. In the past four years, this team from France has achieved the best scores in the petrol classification. In 2009, they won with a consumption of 3771 kilometres per litre, which has stood as a record in the classification ever since. The students from the school now believe that petrol has had its day. This year, for the first time, they are driving on compressed natural gas.

Wearing gloves, some of the teenage students are now polishing their car. A little later, the ecological four-wheeler disappears under a special made-to-measure thick cover. The team clearly has plenty of financial resources at its disposal. “Did you ask whether we were waxing the car to enable it to go faster?” Paillard laughs off the question. “No, we were polishing it purely for aesthetic reasons. That is something the sponsors appreciate.”

“Why is it that we always win? We have been taking part for thirty years now and have been using the same car for the past ten years. We have completely optimised the aerodynamics and the rolling resistance of the wheels.” However, the young engineers are not willing to divulge any more details than that.

Ecological footprint

The IUT GMP Valenciennes team – another French outfit – also ranks among the best, having won the diesel classification for the past three years. They repeat their success this year too, with a diesel consumption of 1323.1 kilometres to the litre. Student supervisor Olivier Deblecker wants the students to drive as much as possible, regardless of the weather conditions. While he and some of his students shuffle slowly forward in the queue in their car, he lets the engine warm up. “That is essential,” says Deblecker. “It is an internal combustion engine and it has to be between 85 and 90 degrees Celsius during the run in order to perform at its best.”

IUT GMP Valenciennes is not the only team to be revving up its engine. The noise makes it difficult to hear what the Frenchman is saying. Moreover, the air is thick with diesel and petrol fumes. “It’s not something that Shell is keen to advertise, but the race does have a significant ecological footprint,” laughs Deblecker. “The cars are economical, but a huge amount of fuel is used before they start the race.”

According to Deblecker, teams who start with a cold engine have no chance of winning. Some of the leading teams have on-board heating in order to maintain the temperature of the engine during the race. However, regulating the temperature itself consumes energy and makes the vehicle a good deal more complex.

“I prefer to keep the car as simple as possible,” the Frenchman continues. “We insulate the engine with aluminium foil. That should do the trick. Another very important aspect is the aerodynamics, and the chassis has to be very rigid as well.” A short time later, after Shell employees have meticulously measured the fuel level in the engine – to the last microlitre – the vehicle appears at the starting line. The flag goes up… but the student at the wheel shows no sign of setting off. Two members of the team hurriedly reach for a telephone: there is no point trying to communicate with the driver directly, as the vehicle is too well insulated. “You can go,” they tell her. “The road is clear.” Banging and clattering, the car enters the track.

So does the Ecorunner, just as the sun comes out. “There are people from our team on every bend,” says AE student Oane van der Heide, who is standing at the finishing line, armed with a laptop. His task is to keep track of the lap times of the Ecorunner. “We want to drive as slowly as possible, because then we are less affected by the air resistance. However, we have to complete the race within 39 minutes, otherwise we will be disqualified.”

The students pass on to the driver any information about how busy the track is and about any accidents that have occurred so that she knows what to expect as she approaches each bend, which enables her to follow the most ideal line.

Obstacles, manhole covers, and holes in the road – no detail is omitted. “We even consider the road markings,” says

Van der Heide. “After all, they are several millimetres thick. If you drive over them, it slows you down.”

“The problem for our team is that it only has AE and Mechanical Engineering students – we don’t have any electrical engineers,” adds Van der Heide. “As a result, we have had to manage without telemetrics this year.” Most teams are able to monitor fuel consumption during the race and therefore calculate the most energy-efficient strategy. The students from TU Delft, though, are not.

The Ecorunner finishes in a time of 38 minutes and 40 seconds. “That was a disappointing run,” says driver Kinan Sutopo, as soon as the cover on the car is raised. “The media car – the car in which the journalists were travelling – was in the way the whole time.”

However, her despondency turned out to be misplaced. The team from Delft achieved the best score in the hydrogen classification in the round, with a consumption of 1227.5 kilometres to the cubic metre. Converted to the energy content, that is 3653 kilometres to a litre of petrol. A tank containing 2.9 kilogrammes of hydrogen would be enough to take the car round the world.

​Shell Eco-marathon

What started in France in 1985 with just 25 wooden vehicles has now evolved into a contest with more than three thousand participants from thirty countries. Students compete in two main categories – the futuristic and streamlined Prototypes and UrbanConcept cars that more closely resemble conventional cars. The exact amount of fuel consumed is measured at the finishing line, from which the distance is extrapolated that could be covered using a litre of petrol or one kWh.

The teams can choose between seven types of fuel. Petrol, diesel, ethanol, GTL or the new CNG (compressed natural gas) are the more conventional types. The alternative energy sources are hydrogen and electricity (with possible assistance from solar energy).

Most of the winners are French, but then again, they have been taking part in the contest longer than anyone else.

The records

The records are astronomical. In 2013, the Lycée Pasquet team rode 1224.1 kilometres/kWh on a battery. If you consider the heat of combustion of petrol, then that is comparable to 10,890 kilometres to a litre of petrol.

Polytechnique Nantes is the undoubted champion in the hydrogen category. Another French team, they managed 590 kilometres/kWH in 2011. That is equivalent to 5248.7 kilometres to a litre of petrol. This year, the team only took part in the UrbanConcept hydrogen category, finishing first with an equivalent consumption of 1121.5 kilometres to the litre.

It should be noted, though, that proper comparisons between the scores achieved by vehicles that run on batteries and those on hydrogen fuels cells are not possible. Hydrogen cars have to convert hydrogen to electricity, generally resulting in an efficiency of sixty per cent. Battery-powered cars have an efficiency of a hundred per cent, because they do not have to undergo that conversion.

The absolute king of the petrol vehicle category is Microjoule La Joliverie. In 2009, the team set the record for petrol cars, reaching 3771 kilometres to the litre. Here is an overview of a few records.






Polytechnique Nantes, France (2011)

590 km/kWh


Electric, on battery

Lycée Pasquet, France (2013)

1224.1 km/kWh



Lycée Saint-Joseph La Joliverie, France (2009)

3771 km/l



Optima, France (2003)

2133 km/l


Compressed natural gas

Lycée Saint-Joseph La Joliverie, France (2015)

2551.8 km/l


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