Watch the most efficient Mercedes of all time: the Vision EQXX. On Tuesday, April 5, this test drive car traveled 626 miles — or 1,007 kilometres, just over a megameter — from its hometown of Stuttgart, Germany, up and over 6,900 feet up the Gotthard Pass in Switzerland to the French Riviera on a single battery 100. kilowatt-hours of charge. The car averaged 56 mph by strictly adhering to all speed limits, peaking at 87 mph along the No-Limit Highway. They stopped twice for 15 minutes, and reached the Cassis after draining just 88 percent of the battery with 87 miles of range remaining (certified by German TÜV authorities). We traveled to the Nice Design Center that crafted the fantastic EQXX to see how this remarkable feat was accomplished and to see how close the upcoming EQC could achieve similar results.
Prioritizing efficiency efforts
The overall goal set for the EQXX team was to achieve a single-digit consumption figure per kWh/100 km (9 kWh/100 km = 233 mpg-e). The Riviera’s race resulted in exceeding 8.7 kWh/100 km (241 mpg). The team prioritized its efforts proportionally to the forces acting on the compact electric sedan at speed: 62 percent of the power expended goes to overcome aerodynamic forces, 20 percent goes to overcome vehicle weight and rolling resistance, and 18 percent goes to powertrain losses.
Lowest Pull Without Fender Skirts
Aero was clearly the development team’s number one priority, and the wheels are a big problem (the front wheels usually create a third of a sedan’s air intake). The easiest (and ugliest) way to fix this is to fit the wheels into the bodywork with skirts or clips, but the team at Nice has been able to reduce wheel drag with very soft, non-obtrusive wheel covers, by outlining the tire wall contours and requiring all stickers to be engraved in the rubber, not the embossing on them, and by inserting the rear wheels approximately 2 inches relative to the fronts, and placing them in the “wind shadow” of the front wheels. The large taper of the greenhouse’s width makes those sensual rear shoulders that hide this “design no” possible (it also benefits in the air), but at a significant cost of backseat shoulder space.
The next biggest aero advancement (good for 0.01 Cd) is the rear diffuser, which extends about 8 inches and dips 3 degrees at speeds over 35 mph to work with the rest of the sharp edge that rings the vehicle’s tail to manage separation airflow and reduce turbulence that causes drag . The rest of the story is more conventional: the smooth bottom and A-pillars, smaller, more aerodynamic mirrors, and a lower “cooling pad” that rejects heat directly to the air passing under the vehicle, meet most vehicle cooling needs, so a conventional radiator should only be used for climate control. or extreme heat. It is fed through the closed vents in the lower grille that removes air through the hood vents. The bottom line: a drag coefficient of less than 0.17 and 2.10 square meters of headroom to reduce overall drag by 29 percent for the EQS sedan (0.20, 2.51 square metres).
Mercedes claims the EQXX tips the scales at 3,870 pounds—slightly less than the 3,902-pound long-range Tesla Model 3 engine we weighed in 2017 with a smaller 75 kWh package. A more energy-dense battery pack that relies on passive cooling is partly responsible. At 1,091 pounds including the one-box charger/controller, it weighs about the same as the 75-kWh actively-cooled package. Electronic design. The team used ZBrush “digital sculpting” software (such as Disney/Pixar used to render Shrek) to shape this massive broadcast, as well as molded front shock turrets, molded rear shoulder strap stabilizers, and 3D-printed aluminum support for the windshield wiper motor. These parts feature only metal where mechanical stresses require it, with lightning holes where pressure does not flow. When necessary, these holes are covered with UBX polymer plates produced from post-consumer waste. There are also composite springs, a carbon fiber rear drivetrain, and aluminum brake rotors.
Engine/battery and solar roof optimization
Mercedes has yet to reveal the full specifications for the EQXX’s battery and motor, except to say it runs at 900V to reduce amperage, cable size (and mass), and overall system losses. The battery still uses nickel-manganese-cobalt chemistry that uses high-silicon anodes and is said to provide 95 percent of the input energy for thrust (90 more typical). The 241 hp eATS-based engine developed by Mercedes uses a new stator coil that takes advantage of Formula E technology that puts more copper closer to the rotor for greater power and efficiency. The roof and rear window area covers 19.4 square feet of 25 percent efficient photovoltaic panels intended to significantly power the infotainment and other non-drive systems, extending the vehicle’s range by up to 16 miles on a sunny day.
Riding in EQXX
With engineering development vehicles developing from scratch in the span of 18 months, this vehicle looked incredibly production ready. The 47.5-inch 8K resolution precision LED (not OLED) display provided impressive navigation information, with an easy-to-use interface and lag-free response. Five different technical data visualization screens displayed plenty of engineering information and environmental training in sharp graphics for players. Sun incidence and wind direction are used to accurately predict solar gain, and aerodynamic effects, road grade and traffic forecasts help estimate the instantaneous range remaining throughout the journey.
The navy and white interior also catches the eye while showcasing an array of new eco-friendly materials (bamboo rug, vegan cactus and mushroom “leather” and e-coli-product faux silk woven textiles) that seem to meet the luxury expectations of the present time. The noise and vibration level could use a bit of work, but the suspension soaked up the bumps with reasonable comfort and the car was nicely boxed and flat. Performance sounded roughly on par with the Tesla 3 motor. On the downside, the low-power woofers, “personal listening” didn’t deliver Burmester accuracy, the back seat was laughably unusable, one had to bend under the low door frames, and the Take a peek at the trunk of the car.
Could the next class C be a megameter amyl?
The size of the EQXX is similar to the upcoming C-class MMA architecture, but the production version will not reach 100 kWh. Raising the roof and widening the rear track and/or greenhouse just enough to provide a competitive rear seat will erode much of the EQXX’s aerodynamic advantage. Engineers describe the EQXX technology as a third now production ready, a third soon, and a third fully experimental. We wonder if the unsealed wheels and aluminum rotors can pass the production car’s brake durability test. Passive-cooled battery power is limited to 100 kW, which may not be considered sufficient in commercial terms. Finally, you should check out a few other drag factors to put the rain gutters on the A-pillars and make the mirrors meet the size and rainfall requirements. But we’d call it a big win if it at least looked like this – inside and out – and was going 450 miles on 100 kWh.