To offer the greatest range without adding ever larger batteries, manufacturers must play with aerodynamics. A challenge that Hyundai has taken to heart with its new Ioniq 6.
You don’t have to be a talented engineer to know that the more aerodynamic a car is, the more it will lower its consumption, whether of fuel or electricity. It is for this reason that large SUVs are sometimes accused of all evils for their overconsumption, despite the progress made. This is even more true when we look at the case of the electric car.
To display the greatest autonomy, the manufacturers of electric cars can put ever larger and heavier batteries, or work on aerodynamics to gain precious additional kilometers. Hyundai offers us a good case study with its Ioniq 6 sedan, which we recently tested. This model shares the same base as the Ioniq 5 family SUV, yet the Ioniq 6 can go up to 107 km further. A difference in autonomy that is not negligible on a daily basis.
Gains of a few kilometers which, once accumulated, make the difference
When addressing the issue of the difference in efficiency between sedan and SUV, two examples can be used:
The example of Hyundai seems to us to be even more telling than that of Tesla. Up to more than 100 km difference in the announced ranges are visible, depending on the configurations:
| 77 kWh – propulsion | 77 kWh – HTRAC (4 wheel drive) | |
|---|---|---|
| Ioniq 6 small rims (18p) | 614km | 583km |
| Ioniq 5 small rims (19p) | 507km | 481km |
| Ioniq 6 large rims (20p) | 545km | 519km |
| Ioniq 5 large rims (20p) | 476km | 454km |
However, these two models, Ioniq 5 and Ioniq 6 share the same technical basis: same platform, same battery, same engine:
- e-GMP platform
- 77.4 kWh battery
- Engine 168 kW propulsion or 239 kW in all-wheel drive
One can imagine that the SUV is larger and heavier than the sedan, but this is not the case. The SUV is certainly significantly heavier than the sedan, between 7 and 25 kg more depending on the configuration, which remains low. On the other hand, the sedan is longer with 4.85 m, against 4.63 m for the SUV. The big difference lies mainly in the design and the result on their drag coefficient:
| ioniq 6 | ioniq 5 | |
|---|---|---|
| Mass | Between 1985 and 2113 kg | Between 2010 and 2120 kg |
| Length | 4.85m | 4.63m |
| Drag coefficient (Cx) | 0.21 (or 0.22) | 0.28 |
We can measure several elements when we talk about aerodynamics: the Cx — coefficient of drag or penetration in the air — or the SCx which is the number related to the front surface of the vehicle. In this little game, an SUV and a sedan can display a Cx with the same value, but a very different SCx. The Ioniq 6 has good results for both elements. Comparisons between manufacturers are made more regularly on the basis of the drag coefficient (Cx).
To position this Hyundai Ioniq 6 against the competition, on the question of Cx, it is placed between the Mercedes EQS and the Tesla Model 3:
- Mercedes EQS: Cd of 0.20
- Ioniq 6 with camera mirror: Cd of 0.21
- Ioniq 6 with conventional mirrors: Cd of 0.22
- Tesla Model 3: Cd of 0.23
We are still quite far from the Cx of the Mercedes EQXX concept which displays a very good 0.17 and a range of more than 1,000 km. Finally, with a score of 0.28, the Ioniq 5 is not as bad a student as it seems.
Hyundai’s Secrets to Efficient Design
Aerodynamics was at the heart of the development of this model. From the concept called Prophecy, Hyundai set the tone with its design inspired by the current “Streamliner”. Then, the design teams and the engineers worked hand in hand to optimize the airflows on all the mechanical and bodywork elements. The work in the wind tunnel alone has allowed Hyundai to gain an additional 10% in efficiency.
The Ioniq 6 sedan isn’t really the only sedan that draws inspiration from the current Streamliner. The Mercedes EQXX concept or the Lightyear 0, which has since been discontinued, also relied on this style. Teardrop aerodynamics did not only inspire the automobile, it was also a trend observable in aviation and on trains between the 1930s and 1960s. Except that this design current, which nevertheless offers good performances, never really found its audience. Let’s hope this new generation does a little better.
Several elements will therefore actively play a role in increasing range by reducing air resistance: in front, behind, above and under the car.
At the front, the Hyundai Ioniq 6 is equipped with an active air flap that will allow the car to intelligently manage the airflow. The damper opens when the system needs to cool down. We could observe it during our test, the shutter opened to cool the battery at the end of our Ionity recharge. Thus opened, the air flows are guided towards the radiator to facilitate cooling. The shutter only remains in this way for a few minutes, before returning to the closed position. When the active flap is closed, the air propelled against the shield is pushed to the sides. The airflow is then redirected to a reducer at the wheel arch, forming an effective air curtain at the wheels.
The other notable element, concerning the design, is located at the rear of the vehicle. The spoiler has been extensively reworked compared to the Prophecy concept car. More than 70 variants of the rear spoiler have even been tested to find the best recipe. The objective is both to ensure efficiency, but also safety, with sufficient rear support to properly stick the Ioniq 6 to the road.
The car’s underbody and rear diffuser also received a lot of attention during development. They should also help to optimize airflow under the vehicle, both for efficiency and to stick the car to the road.
During our test of the Hyundai Ioniq 6, in very windy weather, we felt that all of these aerodynamic elements actively contributed to our handling and our electricity consumption, even if we were above consumption wltp.
Our recommendations to take advantage of maximum efficiency
To take full advantage of the gains made by the aerodynamic work of this model, the customer must know two things to choose his configuration wisely:
- 70 km difference for rims : by opting for 20-inch rims, instead of 18-inch rims, you can lose up to 70 km of autonomy. If you are looking for efficiency, do not hesitate to take the 18-inch rims, you will save on your consumption, but also on the price of the vehicle. The 18-inch rims remove 500 € from the displayed price.
- 10 to 15 km difference for mirrors : camera mirrors offer 10 to 15 km more autonomy than mirror mirrors. The option is on the other hand at 1,200 € and requires a little time to adapt to use.
During our test, we had a rear-wheel-drive version, with 18-inch rims, but classic mirrors. We were therefore quite close to the ideal configuration to obtain the best autonomy. We also recommend choosing 18-inch rims over 20-inch rims. In addition to lowering average consumption, they also provide a little more comfort in use. This is the preferred configuration for us.
For camera mirrors, the contribution of this technology to efficiency is less significant than for rims. It is a choice that is then more your taste for this technological novelty.
Hyundai could do even better on the average consumption displayed by offering the Ioniq 6 with the small 53 kWh battery. This small battery was offered on the Ioniq 5 when it was launched, but French customers mainly favored the large battery. A choice that is quite logical in the face of a model that is not efficient enough. The 53 kWh battery is thus no longer in the catalog in France, neither on Ioniq 5 nor on Ioniq 6. However, Ioniq 6 would lend itself better to the small battery than the Ioniq 5 SUV. We hope that Hyundai will change its opinion on the matter, because it would also lower the entry price of the model which is currently €52,300.
Stylistic choices and work on aerodynamics are not always perceived by the customer. It is an element which, apart from the judgment of aesthetics, is not always very concrete. Nevertheless, on an equivalent route and in similar weather conditions, the Ioniq 5 SUV would necessarily have made more than 10 kWh / 100 km more than average. This difference quickly becomes noticeable when recharging. Lower consumption means: fewer recharging stops, less recharging costs and also a journey time much closer to a journey in a thermal vehicle, for those who are still making this comparison. To save money in the long term, choose an electric sedan whose aerodynamics has been well thought out, rather than an SUV. You will win there.
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