On 24th October 2011, Cidaut started one exciting jorney on board a Nissan Leaf. Since that day, the vehicle has been used as a laboratory for understanding the users’s acceptance, the influence of the weather and the driving style on the battery behaviour, the regenerative braking efficiency and so many other issues that have allowed our sustaineble movility and intelligent transport department to fix important knowledge to build many.
All the vehicle movements have been tracked to understand the influence of driving profiles, roads orography, weather conditions, battery temperature and vehicle payload on energy consumption. Also the charging processes have been monitored to evaluated the influence of low charging vs fast charging, battery temperature and voltage and current evolution along the charging.
Braking system has been instrumented to understand the influence of driving style and battery state of charge on regenerative braking working. Noise measurements in the interior and exterior of the vehicle have been performed and on board thermal analysis has allowed to understand some charateristics of the HVAC system.
The vehicle has been used by more than 200 drivers that have completed surveys and have participated in interviews to better understand the initial users’ acceptance to the electric vehicle use. This information has been valuable for Cidaut in order to advance in the evolution of several projects related not only with the electric vehicle, but also with the connected one.
The finalization of RefreeDrive Project, led by Cidaut, has confirmed that it is possible to manufacture electric motors not only free of rare earths but also avoiding the use of critical materials coming from outside the European borders. The challenge was really ambitious, because the performance objective of the motors was to overcome the figures of a well-known American manufacturer. The ambition was also related to the number of motors to be developed because two technologies have been considered (induction motor and synchronous reluctance motor), two power levels (75kW and 200kW) and two manufacturing processes for each of the technologies.
The eight motors manufactured in the project have been tested stand-alone in a motor test bench to confirm the performance. Two of the solutions have been integrated with the power electronics and the cooling system and have been tested in a specific test bench. And finally, the pure reluctance motor, the power electronics and the rest of auxiliary systems have been integrated into a vehicle to perform acceleration, consumption, dynamic, and range tests.
This development has been made in the frame of the European Project ReFreeDrive, a three years European Project that has recently reached his end. The research leading to this result has received funding from the European Union Horizon 2020 Programme under Grant Agreement nº 770143.
High strength steel tubular frames are a cost effective solution for urban electric vehicles. On one hand the high mechanical characteristics of HSS together with advanced design methodologies makes possible to create an almost non-deformable cabin to guarantee passengers’ and battery’s safety, on the other hand, their predictable behavior and high elongation allow to improve the energy absorption of the collapsible zones.
But one of the challenges of the high strength structures when they are highly demanded is the welding process. In this case the welding process has been optimized to nearly obtain the same mechanical properties of the base material, mainly DP800 and DP1000. But the development has gone one step forward, because Cidaut has developed a methodology to determine the effect of the welding process in the fatigue life of the joints in the vehicle structure.
The methodology is based in the use of finite elements simulations and takes into account not only the longitudinal geometry of the beams, but also the section of the beam and the influence of the welding process. The methodology has been validated through the testing of specimens at laboratory scale, and nowadays is been validated in a full vehicle structure test.
The fatigue loads have been determined thanks to the use of a multiboby analysis, where the everyday manoeuvers have been modelled (curves, braking, small potholes, braking in turn, acceleration,…) and the forces in the four corners of the vehicle have been determined to be used in both the finite element simulation and the validation test.
This development has been made in the frame of the European Project Avangard, a three years European Project that has recently reached his midterm. The research leading to this result has received funding from the European Union Horizon 2020 Programme under Grant Agreement nº 869986.
In the frame of Multi-Moby European Project, which aims at developing of technology for safe, efficient and affordable urban electric vehicle, Cidaut is responsible of the integral safety of the vehicle’s occupant but also of the rest of the vulnerable road users.
Multi-Moby is the last, by now, of a large row of projects that were born from the idea of developing environmental friendly, sustainable vehicles considering circular economy concepts, and will finish with the development of a digitalized micro-factory for the assembly of the final solution. In this project the vehicle safety is being improved that’s to the introduction of automated driving solutions that will contribute to increase the integral safety of occupants and the rest of road users.
Cidaut is in charge of the structural design, the development of the restraint system and the implementation of innovative solutions for vulnerable road users’ protection, all of them supported by the automated driving capabilities of the vehicle. The vehicle will be equipped with artificial intelligence to look out the environment and make decisions to avoid or mitigate the possible accident. In the worst case, if the accident happens, Cidaut’s solutions will minimize its consequences on both, the occupant and the vulnerable road users.
Acknowledgment
The research leading to these results received funding from the European Union (EU) project MULTI-MOBY (GA #101006953).
Since the last update, ReFreeDrive project has attended several international events for disseminating the progress and the main outcomes of the project so far. Recently, on the 1st December, ReFreeDrive participated in H2020RTR Conference, the 4th European-wide conference dedicated to the presentation of results from road transport research in H2020 funded projects. Together with the other two EU projects from the GV-04 cluster (ModulED and DRIVEMODE), ReFreeDrive provided an insightful view of how the European R&D is allowing taking the lead in the electric powertrain field, benefiting the environment, the economy and the society overall.
Besides, we are glad to announce the celebration of the third webinar of the ReFreeDrive’s webinar series the next 16th December, 11:00AM CET. This time, three members of the Consortium will explain some interesting manufacturing facts for advanced induction motors: hairpin stator winding (Mario Vetuschi, Tecnomatic), die-cast copper rotor with zero porosity (David Schmitz, Breuckmann e-mobility) and fabricated copper rotor production process (Denise Willems, Aurubis). You can join us on the following registration link.
Last March, ReFreeDrive Consortium should have celebrated the 30-months General Assembly meeting at IFPEN premises (Paris, France). Unfortunately, the strike of coronavirus pandemic in Europe was at its peak by those dates, which forced serious travel restrictions and made impossible to celebrate a face-to-face meeting as originally planned. Instead, a virtual General Assembly meeting was carried out on 17th March.
This time, the meeting had two main aims. Firstly, to evaluate the impact of the pandemic on each of the partners’ activities and try to figure out to which extent ReFreeDrive’s ongoing project tasks would be affected. And secondly, to monitor and share the results of the tasks carried out in the previous months.
At this point, the e-drive design is finished, including not only the motors, but also the power electronics and its conceptual in-vehicle integration, for both 75 kW and 200 kW applications. Now the focus is on manufacturing and testing activities. Permanent magnet-assisted synchronous reluctance prototypes have been already successfully manufactured, and now we are waiting for the re-opening of experimental facilities to begin testing activities. For the other cases (pure synchronous reluctance motor, die-cast induction motor and fabricated induction motor) some delays will be experienced, so we will work hard in the upcoming months to minimize their impact on the project development. Besides, all components required for the powertrain testing and integration such as gearbox and battery pack have been selected.
Therefore, in the following months it is planned to finalize the manufacturing of the pending prototypes, as well as its testing. Then it will be time to integrate them in the target vehicles and demonstrate its operation in a real environment.
