Here’s How the Hyundai Ioniq Beat the Juggernaut Toyota Prius in MPG Ratings
The Toyota Prius hasn’t just been synonymous with hybrid technology; the idea has been the most fuel-efficient design within the U.S. market for years. along with also also since its 2016 redesign, the Prius Eco has been the most fuel-efficient gasoline-powered car without a charging port, ever. So how does the Hyundai Ioniq hybrid’s Blue design, right out of the gate, jump to a spot ahead of the Prius having a combined 58 mpg, producing the idea the most fuel-efficient hybrid available within the United States?
First, Hyundai has more development years invested than you might think. A dedicated team within Hyundai began working on hybrid powertrains nearly 12 years ago, along with also also developing its so-called TMED (transmission-mounted electrical device) hybrid system 10 years ago. TMED made its debut, as a system, at the 2008 Los Angeles auto show along with also also then in production form within the 2011 Hyundai Sonata hybrid.
As we concluded on our first drive of the Ioniq hybrid, that will is actually a car with reasonably not bad drivability, along with also also while we won’t call the idea downright sporty, the idea carries a perkiness that will’s missing via the Prius’ powertrain. the idea’s hard to believe the Ioniq’s hybrid kit is actually derived via the system in that will 2011 design, in which a lack of finesse in that will hybrid powertrain made drivability downright clumsy. nevertheless with reworked software Hyundai has made tremendous strides since then. The Ioniq makes the most of the efficiency potential in that will hybrid design, having a different engine along with also also transmission than the Sonata hybrid, along with also also a Centeng structure along with also also platform that will were conceived via the start to be hybrid specific.
At the Ioniq’s U.S. media launch that will past week, we asked several key project members how they managed to best the Prius with the automaker’s first attempt at a dedicated hybrid. along with also also here’s what they pointed to:
An engine that will runs lean. According to Yong-Seok Kim, the team leader for eco-technology performance development, thermal management along with also also that will engine’s claimed 40 percent thermal efficiency (same as that will of the Prius) are two of the most significant factors, as are some fundamental design choices, such as the engine’s long 1.35 stroke-to-bore ratio. The 1.6-liter Atkinson-cycle Kappa four-cylinder uses the engine-block dimensions otherwise reserved for engines within the 1.0- to 1.4-liter class, keeping its thermal mass to a minimum. Split cooling circuits for the head along with also also block as well as a cooled EGR system help keep the air charge consistent along with also also cool. A 2900-psi direct-injection system (the high end of today’s gasoline DI) aids combustion efficiency.
Battery along with also also power controls. The second most important thing, according to Kim, is actually the Hyundai’s battery-control strategy. Compared with Toyota along with also also various other automakers, Hyundai has more experience using lithium-ion batteries, he says, along with also also much more (higher resolution) data on how to use the battery at particular temperatures along with also also conditions. “So even if GM, within the Volt or Bolt EV, uses the same chemistry along with also also battery, we guarantee the idea with more warranty, along with also also our efficiency is actually better because our control algorithm is actually better,” said Kim.
Very little lost in translation. Hyundai’s choice of transmissions also works toward maximizing efficiency; the dual-clutch automatic within the Ioniq carries a torque-transfer efficiency of 95.7 percent—better than a planetary automatic transmission, a CVT, or the Prius’s two-motor power-split arrangement. The various other advantage, as we’ve already found out with some driving time, is actually that will you feel more connected to the powertrain while accelerating; there’s none of the detached, motorboat-like sounds you get within the Prius—or within the Honda Accord hybrid, where Honda has shown how the idea can eliminate the transmission (along with also also those mechanical losses) completely.
Cutting drag. The Ioniq team attacked all aspects of drag, starting with carefully tweaked aerodynamics. All versions of the Ioniq have a super-slippery 0.24 coefficient of drag (along with also also we’re impressed that will the team didn’t have to skimp on side mirrors to get there). All Ioniq versions with an internal-combustion engine (hybrid along with also also plug-in-hybrid versions) have automatic grille shutters. Underbody shielding is actually used across the lineup. The brake calipers’ pistons retract slightly to avoid any unwanted pad-on-disc drag when you’re not stepping on the pedal, while Blue versions have special aero-optimized wheels. Getting very low rolling resistance is actually the various other crucial piece. Hyundai is actually using Michelin tires—Michelin Energy Saver A/S tires on Blue along with also also SEL versions along with also also, on Limited versions, Primacy MXM4 tires (priced at $166 each by Tire Rack), which Kim said are the most expensive tires he has ever used.
Putting the 58-mpg Blue on a special diet. Obviously, reducing weight is actually an important step, too. Hyundai didn’t just work to keep mass at a minimum in major components—aluminum hood, liftgate, along with also also suspension components, 54 percent high-strength steel for the core Centeng structure—the idea also spent a lot of effort micromanaging weight on the features level. that will’s especially true within the base Blue design—the one that will gets a 58-mpg combined rating, while the rest of the lineup gets 55 mpg.
that will bears a little more explanation, though. The U.S. EPA requires vehicles to be grouped into 125-pound weight classes—inertia classes, actually. If an option—leather seats, for example—is actually applied on more than 33 percent of vehicles, then the weight of the seats has to be accounted for within the vehicle’s ETW. Sunroofs are a not bad example, because they weigh about 28 pounds—an amount that will can easily push a vehicle into the next test class—according to John Shon, the manager of product planning at Hyundai Motor America.
While there’s no difference in powertrain or core functionality via Ioniq Blue to mid-level Ioniq SEL along with also also the top-of-the-range Limited, Hyundai whittled the Ioniq Blue, which has no major options, to a lower test class than the rest of the lineup by keeping a tight rein on equipment (along with also also actually, there are just 5 build combinations of the entire Ioniq hybrid lineup, aside via coloration choices). The Blue omits the various other versions’ rear center fold-down armrest, power driver’s seat, heated front seats, lower door molding, along with also also blind-spot monitor, all of which add weight, as well as LED headlamps, which don’t. within the noise-isolation area, the Blue design gets its own (lighter) dash pad, trunk mat, along with also also carpet. A wheel design specific to the Blue design saves two-thirds of a pound per wheel.
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the idea’s all part of some careful planning made by Shon along with also also his U.S. team to manage expectations along with also also make sure that will buyers of the most fuel-efficient Ioniq get what they want—along with also also that will buyers of more lavishly equipped versions aren’t disappointed with their real-world mileage. “You see quite a bit of that will throughout the industry,” explained Shon. “Ultimately, you want to give those customers that will choice, because as you add weight along with also also features, you’re going to get lower fuel economy.”