Recap 2022
Our journey 2022
This year we will be the only car driving on Hydrogen. This ‘race’ is meant to show everyone what we do and to convince other teams to join our hydrogen category. This way we can race against other teams next year and we stimulate other teams to discover the possibilities of hydrogen.
Monday: Our subteams
Management
“The connection between the different expertises and team members is of great importance for the team. By stimulating personal growth and innovative thinking, the management raises Green Team to a higher level.”
1. Get an overview of all the processes in the team
2. Contact with companies about support
3. Weekly meetings with the subteams
4. Create a safe environment
5. Set learning goals and evaluate the progress
Hydro-electric
“The powertrain is everything with high voltage, from where the energy is generated to the conversion of energy in motion, which happens in the motor.”
1. Get sufficient background knowledge about similar systems/products.
2. Get the requirements clear.
3. Search for products that meet the requirements.
4. Compare the products and get the best one while still keeping the budget in mind.
5. Integrate the product within the system before ordering.
6. Test the individual parts and if successful, start testing more and more parts together till the entire powertrain functions correctly.
7. Analyse what went wrong or can be done better and start from step 1.
Cooling-system
“The cooling system might be the most important subsystem of the car because it prevents the drivetrain components from overheating.”
1. Get an overview of the cooling requirements of the drivetrain components.
2. Performing heat transfer calculations to make design decisions on the cooling system.
3. Designing radiators that provide sufficient cooling and will still fit in the car.
4. Organizing the liquid-cooled components in a system layout. Therefore we need to take into account each component’s requirement regarding flow, temperature and pressure drop, and heat dissipation.
5. Discuss the duct design with the aerodynamics team. The duct is the piece of bodywork surrounding the radiators. A great duct design increases the efficiency of the heat transfer.
6. Testing of the cooling of individual components.
7. Securely mounting and wiring the cooling system components.
Extern & Finance
“Recruiting new partners and keep in contact with existing ones for money, knowledge and parts. We are continuously searching for partners who want to help us.”
1. Prepared Standard Packages that are adapted to the wishes of the partners
2. First look within your own network, you already know people, there are leads, and you can come through somewhere and search the Trello for companies that have already been approached.
3. Calling and emailing and working towards an appointment
4. Consult with Mechanics and Electronics about the state of affairs and which parts are needed. They approach entire technical companies themselves, but they help externally with concluding a contract. Very specific parts also run through the technical manager.
5. For large amounts and technical things, we work closely together, such as with the fuel cell
6. Also provides information to the sub-teams
Communication
“Educating and spreading awareness about hydrogen and its uses, as well as showing what green team does. The team image.”
Public relations and Graphics
1. Start brainstorming who is it for and what is the goal.
2. Without thinking a lot of ideation.
3. Ask for feedback and see which is the best option
4. Elaborate and ask for feedback until you think it’s right
5. Reflection on whether it belongs to the goal and target group
6. Publish after last feedback
Events
Make sure we know what is expected of us, where should we be, what is in the budget, what do we want to achieve, what do we show, and should we bring
Education
Making schools enthusiastic about hydrogen, subsidies, education series, workshops, green team twente young
Mechanics
“Design all mechanical parts in a way that optimal racing performance is achieved and that all parts work well together.”
1. Analyzing the different parts and understanding the technology behind them
2. Invent and elaborate different designs
3. Define parameters
4. Modeling designs in CAD software
5. Optimizing designs based on force calculations and technical insight
6. Produce the final design yourself or send it to companies for production
7. Enter the workshop to assemble and test all parts
Tuesday: Our car, random facts and information
Random facts about the car
- 1 single cell in the Fuel Cell can produce more than the power we consume with the Aurora Omega. The fuel cell stack consists of 215 of these cells which can produce up to 49 kW altogether.
- The pressure on a car tire is approximately 3 bars. We store our hydrogen at 100 times that pressure, so 300 bars.
- On the energy stored in the capstack we can drive 36 seconds on race pace. The same energy can be used to power a refrigerator for 3 hours.
- The chassis consists of 107 tubes welded together
- One wheel can easily take a load of 1000 kg
We have multiple systems. From our cooling system to the hydrogen system, to the drivetrain, safety system, and mechanical system. All working together as one team. Resulting in the following statistics.
Hydrogen system
The reaction of Hydrogen and Oxygen makes the flow of electricity possible. The voltage coming out of the fuel cell stack is not steady and is too low to power the motors. This is why the DCDC is needed. The DCDC increases the variable voltage to 400 V. After this, a supercapacitor pack (capstack) is used to store the energy for a short while. The motor controller then draws power from the capstack and transfers the electricity from DC to AC and into the two rear motors.
Control and safety
Since we work with high power and a hydrogen system, we have to pay special attention to safety. Our main priority is therefore to drive safely! In order to do this, we have a safety system with sensors detecting deviations throughout the entire car. One is the impact attenuator in case of a frontal crash, another one is the hydrogen sensor placed high up in the car so that it can detect hydrogen. And many more. If any deviation is detected by the sensor, the drivetrain will shut down. This means that every component shuts down and stops working. All the devices ensuring safety need to be powered at all times, so when the main power line fails to deliver power, a secondary independent power source is needed to take over.
-Brake System Plausibility Device-
One part is the BSPD, The Brake System Plausibility Device. As can be quite easy to understand. The Key point of this device is to prevent that power goes to the motor controller when hard braking occurs. This can happen when the motor controller malfunctions or has bad communication with the pedal box. In this case, the Drivetrain needs to shut down.
This is done with multiple sensors, a current sensor, and 2 brake sensors. The brake sensors are attached to the brake system to detect braking and the current sensor measures the current flowing to the motor controller. When both measurements reach their threshold the drivetrain will shut down and stay that way until it is reset. Also when an error occurs within the sensors or has a disconnection, the BSPD will try to detect this and will shut down the drivetrain safely
Cooling system
Designing a cooling system has never been done in the history of Green Team. Making it an exciting but particularly difficult task. Dealing with unknown components, missing information required to do heat transfer calculations and more complications were faced during this year. But as with any challenge, you will overcome it in the end.
We have two cooling cycles. The first one is the fuel cell cycle and the other one is for all the other components in the drivetrain.
-Radiators-
We designed our radiators to meet these requirements. The design of the radiators is vital because these are the components that will transfer the heat from the fuel cell and the drive train to the surroundings.
For each cycle, we use one big radiator, both radiators being able to cool around 24 kW’s, which should be enough to cool the fuel cell at average performance. We place them both under a slight angle. This angle in the radiator placement makes sure we can maximize the heat transfer area in the limited space available to us.
Adding to the performance are a couple of fans and our duct design. Fans on the back of the radiator draw in even more air to pass the radiator fins. And the duct is the piece of bodywork on top of the sidepods, enclosing the radiators, guiding the air flow for more efficient heat transfer.
Mechanics
Since we are switching to the Formula Student, the design of the suspension is totally different than the SEM car. The front and the rear suspension of the FS car are slightly different, as the set-up needs to be different for the car’s performance.
The knuckle and hub are designed by ourselves and are based on different load cases, so we know that one wheel can easily take a load of 1000 kg. It was also a challenge to attach these components together with the double-wishbone structure to the chassis and the spring dampers. There was not much space left for our spring dampers, as we had to place a 22,4 kg hydrogen tank in the car, because of this, as in ordinary cars, we place the engines and gears in the wheel assembly.
Therefore, our spring dampers are placed slightly differently than other FS cars. Our spring dampers are connected to the lower tubes of the back.
Wednesday: Technical inspection
Pre-inspection
This includes underclothing consisting of a balaclava, underwear, and socks. The driver’s overall and accessories, which are suitable shoes, a helmet, and gloves. All these items should be fire-resistant and strong enough to protect the driver when an accident occurs. Besides, the helmet should cover the driver’s mouth and not only his head because a full-coverage helmet is stronger.
Accumulator inspection
The accumulator, our capstack, is an energy stack that is used to store energy. The fuel cell stack delivers constant power. However, the motors don’t need constant power, since they use power in a fluctuating way. Hence this is why we need a energy buffer; the capstack!
When the car accelerates it needs maximum power. When you race, it needs a bit less. With braking, you don’t need power at all. Breaking gives energy back to the capstack, this is called regenerative braking. The capstack exists because of this difference in energy consumption. The capstack will be tested to ensure safety.
– Basic tools –
First, the set of basic tools will be checked. Insulated cable shears and screwdrivers are needed because the capstack works with a high voltage. A multimeter with protected probe tips, face shield, two pairs of HV insulating gloves, two HV insulating blankets, and safety glasses with side shields for all members who work on the accumulator or tractive system. The tractive system covers all high voltage parts of the car to ensure the motor works.
– Charger & temperature –
Next to the basic tools, the charger of the capstack will be inspected and sealed. This is important because a wrong charger can cause a fire. Besides the charger, an official temperature logging device must be installed. This device measures the temperature and makes sure the capstack turns itself off when it becomes too hot. When the driver races, the other team members can also keep track of the temperature because the device sends its data to a computer as well.
Electrical inspection
Before the electrical inspection starts, some requirements are walked through. One of the team members should be assigned as electrical safety officer, ESO. The Tractive system capstack should be mounted to the vehicle. Samples of the self-designed PCBs, printed circuit boards, which are parts of the tractive system should be shown. Tools for the de BSPD, brake system plausibility device, check should be brought and all data sheets of the tractive system. The technical inspection focuses on two tests.
– High voltage vs low voltage system –
The first test is a test about preventing short-circuit. In the car, there is the tractive system, which are all the parts on a high voltage and there is the low voltage system, which are all the parts needed to power the safety system such as the shutdown circuit and cooling system. There should be a high resistance between these two systems to prevent short-circuit and because the systems will not work well when there is low resistance. That is why the resistance between these two systems is tested.
Vehicles with a maximum TS voltage less than or equal to 250 V will be probed with 250 V and vehicles with a maximum TS voltage greater than 250 V with 500 V. To pass this test, the measured insulation resistance must be at least 500 Ω/V related to the maximum TS voltage of the vehicle.
– Insulation monitoring device –
Secondly, you do not want the chassis to be charged unnoticed. This is why you need an earth leakage circuit breaker, which is for the car a device called the insulation monitoring device, IMD. The device shuts down the entire tractive system when the chassis is under high voltage. Therefore, it is very important to check the insulation monitoring device.
It is tested by connecting a resistor between the tractive system measuring port and the low voltage system ground connector. The test is passed if the IMD shuts down the tractive system, within 30 s at a fault resistance of 50 % below the response value which corresponds to 250 Ω/V.
Mechanical inspection
The mechanical inspection mainly consists of providing materials and documents. Copies of any safety structure equivalency forms should be handed in, such as all structures from the chassis. Copies of any impact attenuator data requirement, among which the material specifications and how it is attached to the chassis. This impact attenuator is a hardened bumper, which makes sure the car will not break immediately when crashing into something. There should also be a test piece of the impact attenuator brought to the inspection. The tallest driver of the team should take place in the car, the car should be ready-to-race and a quick jack and red push bars should be present. A quick jack is kind of a pallet jack which can move the car for- and backwards and the push bars are handles on the car which can be used to push and turn the car.
Tilt test
To make sure the car will not spin out it is important to have the right point of gravity. To make sure this is the case a tilt test will be performed. This test will be conducted with the tallest driver fully strapped in normal driving position and all fluids will be at their maximum fill level. The car will be placed on a table which will tilt to an angle of 60°. To pass the test, there should be no fluid leaks and all wheels must remain in contact with the table.
Vehicle weighing
Before the car can race it will be weighted in ready-to-race conditions, so including driver. This is done to prevent teams from removing or adding parts after the inspection. When the weight difference differs more than 5 kg you will get penalty points.
Rain test
Before the test the wheels should be removed and the vehicle must be placed on the quick jack without driver to prevent the car from driving away in case of a short-circuit.
Water will be sprayed at the vehicle from any possible direction, which will be similar to a vehicle driving in rain and not a direct high-pressure stream of water. The test is passed if the insulation measurement device is not triggered while water is sprayed at the vehicle for 120 s and 120 s after the water spray has stopped. The insulation measurement device detects if there is voltage on the chassis, this is why you do not want it to be triggered.
Brake test
– Brakes-
Having a brake test speaks for itself. The car should be able to stop to prevent any accidents. All four wheels should be locked and stop the vehicle in a straight line at the end of an acceleration run specified by the officials without stalling the engine. After accelerating the tractive system must be switched off by the driver and the driver must break only using mechanical brakes.
– Lights –
However, not only the brakes are tested. Next to the brakes the brake lights will be tested and observed if the illumination is good enough. The TSAL light, tractive system active light, should also work. These lights blink red if the tractive system is active to ‘scare’ people. Red means there is high voltage and you should not just touch things. The light will be off when there is an error and green when the voltage is below 60V.
– Sound –
Finally, the horn is tested which will be used to make clear you are ready-to-drive.
Thursday: The Formula student, racing and the circuit
The race is seen worldwide as a gateway for university students to, for example, Formula 1 and the WEC (World Endurance Championship). Besides gaining experience in the racing world, the FS is a perfect way for students to gain all-round engineering/work experience. Ross Brawn, Formula 1 Managing Director, said:
“I can speak from personal experience when I say that practical experience is essential for a good engineering foundation. Formula Student combines the practical applications with the academic study of the students, but also teaches the students important skills such as project management, dealing with finances and teamwork.”
Besides the engineering and racing part, the FS is also about students developing other skills such as designing, presenting and making a business case. The idea of the business case is that you try to make a car for the market of non-professional hobby racers.
The race has three classes, combustion, electric and driverless. We are now going to set up a new classification, the hydrogen classification. This year we will be the only one and we hope to pave the way for other teams to switch or start with hydrogen.
This year we have the honor to be present at Formula Student Netherlands and Germany. These will take place at TT axes and the circuit of Hockenheim.
– Formula Student Netherlands (FSNL) –
This year will see the 5th edition of FSNL. This will be at TT Assen, the home of Motor GP. This will be the first venue where we will show our new hydrogen FS car. Besides us, there will be 50 other teams from three different continents.
– Formula Student Germany (FSG) –
The FSG is considered the world championship in the FS race! It is the largest in the world and is held on the Hockenheim circuit. Formula 1 was held here until 2019. Almost all FS teams want to take part, but in the end “only” 100 are allowed to do so.
KIWA
In every FS race, you always have to go through the technical inspection as told yesterday. This is to check that the car is completely safe and there is little that can go wrong. Making a completely new kind of car is of course not without danger. Hydrogen is not exactly more dangerous than electric or combustion, but of course it has to be checked properly. For this technical inspection we work together with KIWA. KIWA is a specialist in Testing, Inspection and Certification. They also do this in the field of hydrogen and so they can properly check if our car is completely safe.
Friday: Hydrogen
Storage
Hydrogen can be stored in gas or in liquid form, but mostly gas tanks are used with a pressure of 350-700 bar. Hydrogen storage technology has developed rapidly in recent years and is way safer than people think. Modern aluminum-composite tanks provide excellent storage being able to withstand point-blank gunshots without taking a dent.
Easy refueling
Energy density
Proven technology
Hydrogen economy
Sustainable fuel
Hydrogen is produced by electrolysis, using electricity to split water into oxygen and hydrogen. The production of hydrogen can be done with green electricity; energy that is generated by sustainable methods such as solar or wind power. Because of this green production and water is the only byproduct, hydrogen is a sustainable fuel.
Shell Eco-marathon
Our race updates 2022
Day 4 Friday
After a full evening of deliberation and a short nights rest we started the day with a plan. We used the knowledge gained from our first attempt to adapt the car and our driving strategy. With big results! Where we started of with a score of 140 to which our competitor HAN must have felt pretty confident. However each attempt we leapt forward, first 200, then 278.
It is 17:00 Aurora omega rolls up to her last attempt. Disaster strikes, she is not allowed on track. Of all things the seemingly simple horn malfunctioned. The clock chips away at the time as we scramble to find a solution.
One of our competitors had the replacement part we needed. Our fourth and final attempt was saved. We would like to point out the amazing cooperative atmosphere in the paddock. Even though some of us were directly competing we lended our tools and parts out and got ones we needed in return. Giving everyone their best shot at showing of their year long hard work.
Our driver Bas rolled up to the starting line just in time for our final attempt. 275 was the score to beat, held by HAN. As Bas drove off we cheered him on. A little time passed and then Bas told us the terrible news. “A tire is scraping the wheel arch.” It went quiet.
It was a nerve wracking wait. Aurora drove one lap even more gracefull than the last. After she finished on the dot the efficiency was calculated. The field radio buzzed the score. We asked for a repeat, we couldn’t believe it. As we heard 305 again we erupted in total joy.
Dispite all the setbacks, like a broken fuelcell a month before the race. We managed to set an amazing score. 4281 kilometers on a single kilo of hydrogen. That is from Enschede well into the Saharan desert.
We’d like to congratulate Eco-Runner and HAN with their victories and wish them good luck next year. This was a great end of an era for us. We’re looking forward to exploring the high performance possibilities of hydrogen.
Still, in the morning we had to make some adjustments and refinements to be ready for the inspection. For example, we had to integrate the telemetry device, two joule meters and a flow sensor into the car. The telemetry device sends all our data from the car to the Shell Eco Marathon organization. Integrating these parts came with some struggle as the connections didn’t all fit. Some new cables and connections had to be created that hadn’t been in the car before. In response to that also some extra cable management had to be done. At the end of the morning, we plan to be ready to go through the technical inspection and hopefully pass it without any issues.
Part of the team also performed a track walk this morning. It was exciting to inspect the track from up close that so far we have only seen on paper. We got the chance to discuss the optimal racing line and our racing strategy that we have in mind while walking the actual track.
Day 1 Tuesday
Early in the afternoon we arrived at the campsite. After setting up our tents we went to TT Assen for the first day of the SEM. We are not going to race today because this day is purely meant for preparing for the race.
First we had to sign in at the reception, part of this was watching a video on how to act safe in the pitbox. Next, we went to the paddock to unload the car and tools into our pitbox.
Once everything was setup we went to pick up the telemetry devices from the organisation. These report data from our car back to Shell. So they can check us during the race. This includes a flowmeter, joulemeter and an onboard computer.
Thereafter the openings ceremony was about to begin. All the competing cars where set up in the pit lane for a nice group picture, with the Aurora Omega in the front left.
Once the ceremony was over, with only one hour left before the paddocks would close, we started installing the telemetry equipment.
Green Team Twente competes within the Shell Eco-Marathon. This is an unique competition that challenges students around the world to design, build and drive the most energy-efficient car. With three annual events in Asia, America and Europe, student teams compete on efficiency: who can drive the furthest on the least amount of fuel?
The competition is split into two vehicle classes, the Prototype class and the Urban Concept class. Cars in the prototype class are all about the ultimate performance, meaning there are no design boundaries. Cars in the Urban Concept class also drive as efficient as possible, but are design-wise restricted to resemble current cars and are also assessed on their driving performance.
Among these two main classes, cars are divided by energy-categories. There are subclasses for cars propelled by an internal combustion engine fueled by gasoline, diesel or ethanol. As well as for cars driving battery-electric and driving hydrogen-electric. In the final race, the Drivers World Championship, all different subclasses race each other, in the ultimate car of the future race. Green Team Twente is a participant in the Urban Concept class, driving hydrogen-electric.
WORLD CHAMPION
2019
WINNER SHELL ECO-MARATHON
2019, 2017, 2012
3rd PLACE SHELL ECO-MARATHON
2016, 2013
WINNER COMMUNICATION AWARD
2020, 2019, 2018, 2017, 2015
