Hyundai begins rollout of Ioniq Hybrid, PHEV and EV; most efficient non-plug vehicle, most efficient EV in US; powertrain discussion
Hyundai has begun the US sales rollout of its Ioniq line of electrified vehicles, which come in hybrid, plug-in hybrid and battery-electric variants. (Earlier post.) At a media preview in Santa Barbara this week, Hyundai executives said the the hybrid will be moving into showrooms shortly, the battery-electric version in April (in California initially), and the plus-in hybrid in Q4. The Ioniq Hybrid boasts the highest fuel economy in the US (up to 58 mpg) for a non-plug-in vehicle and the Ioniq Electric is the industry’s most efficient EV (136 mpge).
All three variants were available for media drives this week (drive impressions embargoed until next Monday); the hybrid and EV versions were production cars, the plug-in was still characterized as “prototype.” Nevertheless, technical executives and engineers from Korea and from the Hyundai-Kia America technical center in the US were on hand to provide market and technical background. Furthermore, two engineers from the US technical center gave presentations last week at the SAE 2017 Hybrid & Electric Vehicle Technologies Symposium in San Diego, discussing aspects of the hybrid and battery-electric powertrains, including some of the unique features and Hyundai “firsts” represented in the Ioniq.
|Ioniq Hybrid. Click to enlarge.|
This Ioniq project is more meaningful for us than a normal eco-friendly vehicle project. The Ioniq hybrid and electric platforms will be our future e-mobility foundation.— Ki-Sang LEE, Hyundai Senior Vice President R&D
Market background. Mike O’Brien, Hyundai vice president of corporate and product planning, noted that the “green car market” in the US has declined a bit—about one hundred thousand units since its high in 2013 with 3.8% market share for all electrified vehicles (hybrid, PHEV and BEV). The market has stabilized over the past two years at about 2.87% share for electrified powertrains.
Overall, the number of hybrid models on sale in the US has declined (from 47 in 2015 to 31 in 2016), but average sales per model has increased (up to 11,194 in 2016). Plug-in hybrids have seen a steady increase in the number of models, accompanied by a decline in the sales per model, as the demand has not kept up with the new model introductions. For EVs, both the number of models and the sales per model have been increasing steadily year over year.
Government policies and regulations will continue to drive the development and adoption of alternative powertrains, O’Brien noted. In addition to the regulatory impetus, a number of megatrends are transforming the automotive marketplace. Among these are the generational shift from Boomers to Millenials, urbanization, the development of connected and autonomous vehicles, and the benefits of electrification.
This is our first dedicated green vehicle. It is the first vehicle available globally that has three available powertrains for it. The idea is to give our customers choice. They can choose the level of green, the level of electrification that mets their driving style and wallet.
We are the highest fuel economy of any hybrid, of any gasoline car without a plug sold in the US. We are the highest in EV efficiency of any car sold in America. That means less carbon and lower cost of ownership. And we are the best in operating costs.
According to the EIA, still today, 67% of the electricity that goes into EVs comes from carbon. All we are doing is moving the tailpipe from the car to a smokestack someplace else. The important thing to remember is that if we are serious about reducing carbon in personal mobility, we have to be very serious about efficiency. [Efficiency is] The most important metric. We focus a lot on range, which is very important, but we need to focus more on efficiency. With 67% of our electricity today coming form carbon, we need to think about efficiency being a more important metric as we move forward.—Mike O’Brien
Development background. Hyundai has been developing eco-focused vehicles for some two decades. Its current offerings are electric, hybrid, plug-in hybrid and fuel cell technologies.
Hyundai is on its second-generation of Hyundai Sonata and Kia Optima hybrids. (Earlier post.) Customer and reviewer response to these has led Hyundai to the higher volume and more competitive eco segment—e.g., the Hyundai Ioniq and the Kia Nitro, said Dean Schlingmann, Senior Hybrid Powertrain Engineer at Hyundai-Kia America Technical Center, at SAE 2017 Hybrid & Electric Vehicle Technologies Symposium.
The Hyundai Ioniq/Kia Nitro platform is designed from ground up to maximize efficiency and minimize compromises that have been seen in the past when trying to hybridize an ICE vehicle. The Ioniq and Niro powertrains are, for all intents and purposes, identical. Design objectives included:
Fuel economy. Ioniq and Niro represent high volume segments for Hyundai/Kia US fleet; the engineers were tasked to design a hybrid powertrain with segment-leading fuel economy.
Cycle vs off-cycle fuel economy. The vehicles need to attain high fuel economy in the real world.
Driveability. Hyundai targeted designing the powertrain for a “segment-appropriate” drive experience.
Cost effective. Hyundai intends to be competitive both with fuel economy and sticker price.
Collaboration. All departments need to work together to achieve the goals.
This is kind of a moon launch for us. The interior can no longer function separately from the fuel economy team. Everybody has to work together, communicate, focus on same objectives.—Dean Schlingmann
The end result for the Ioniq was an up to 58 mpg (4.05 l/100km) combined fuel economy—the highest rating of any non-plug-in vehicle sold in the US market—and 50 mpg (4.7 l/100 km) for the Niro. (The 58 mpg rating is for the “Blue”, entry-level trim on the hybrid. The two higher trims see their fuel economy drop slightly.)
Hybrid Powertrain. The Ioniq hybrid powertrain consists of a new Kappa 1.6 direct-injected Atkinson-cycle four-cylinder engine with a thermal efficiency of 40%, delivering an estimated 105 horsepower (78 kW) and an estimated 109 lb-ft (148 N·m) of torque. This engine is combined with a six-speed double-clutch transmission and new, transmission-mounted electric device (TMED). A 1.56 kWh Li-ion polymer pack from LG Chem provides the energy storage. Total system output is 139 horsepower.
|Top: Rear view (i.e., facing forward) of the hybrid system in the Ioniq Hybrid. Bottom: Front quarter view. Click to enlarge.|
Each of the major powertrain elements is new or newly optimized for the hybrid application, and features some firsts.
The engine added a number of technologies, some Hyundai has not used previously on a hybrid system. The Atkinson cycle engines features head-block split cooling with a hollow exhaust valve, a long stroke, cooled EGR, and low-friction coating. An electric water pump and variable pressure oil pump add to the efficiency of the engine, which also uses an OCV (oil control valve) dual Continuous Variable Valve Timing (CVVT) system.
The new 6-speed DCT—specifically designed for hybrid applications—with integrated motor features fast and controllable mode changes, with shift assist motor torque control. The 6DCT features low-friction technology with best-in-class torque transfer efficiency (95.7%) to maximize fuel economy. The hybrid power control unit integrates two motor control units (traction motor and hybrid starter generator) and DC converter are all in the same package. The cost-effective DCT transmission delivers a familiar automatic transmission drive response.
The new, water-cooled traction motor reduces the thickness of core components by up to 10% and adopts rectangular-section copper wire to decrease core and copper loss, rather than the previous round wire. The rectangular wire improves the slot fill factor (from 51 to 54%). Improved efficiency and new software methods increased the peak power, which started at 25 kW and went to 32 kW. The new Hyundai motor, with 170 N·m (125 lb-ft) of torque has a torque density of 75.8 N·m/L and an efficiency rating of 95.3%.
The high-voltage Li-ion battery package includes not only the energy storage system for the hybrid powertrain, but also a Li-ion 12V auxiliary battery; this packaging allowed Hyundai to remove the 50 Ah AGM battery, saving 26 lbs (12 kg) in the process. The Ioniq always monitors state of charge (SOC). If the 12V battery is deactivated for some reason, the driver can push a battery reset button/ If the button does not work, or if there is some unforeseen scenario, there are jumpstart studs. In the worst case, the 12V battery, which is modularized within the larger package, can be serviced.
The 240V, 6.5 Ah, 42 kW traction battery uses NMC cells; the pack is mounted under the rear seat to open up additional passenger space and cargo space. The pack is 20% lighter than non-polymer lithium-ion batteries and can be shaped more optimally to the interior than standard cell format batteries, Hyundai said.
This is a very simple system. Imagine a conventional transverse engine and a 6-speed DCT architecture. Just split the engine and DCT and insert a clutch and motor between the two, with the clutch dividing the engine form the motor.—Dean Schlingmann
System response is quick as a result of this simple design, Schlingmann said, and easy to control when changing modes from EV to HEV. The engine can be synched with motor speed through a combination of torque demand from the hybrid starter generator as well as engine rpm control (unless the engine has started switching from HEV to EV mode and decoupling and shutting down).
Shift control and gear torque balance has increased tunability. The new 6DCT has a measurably higher power transmission than the automatic transmissions used in past systems. Gear shifting is much quicker, with increased system efficiency and regeneration energy capture, mainly because the system is in gear more often than the traditional automatic, Schlingmann said.
The Ioniq Hybrid offers three primary operational modes, with a fourth (series mode) for special cases only.
EV mode. For low-speed and light throttle. The clutch is open, hence no motive power from the engine. When the battery SOC is low, the DCT couples to the engine and Ioniq moves to HEV mode.
HEV mode. The vast majority of operational time is spent in either EV or HEV modes.
Charge mode. This is a driver-selectable mode capable of increasing SOC—and is more useful in the plug-in hybrid version.
Series mode. In this mode, the clutch is open, but the engine is running, sending power to the battery via the generator. A use case is creeping up a steep grade—driving too slowly to couple the engine to the motor. This mode will provide continuous electrical power to the motor.
Enhancing the car’s fuel efficiency and dynamic driving characteristics, the driver can select either SPORT or ECO modes. The SPORT function holds lower gears longer and combines power from the engine and electric motor for maximum performance. In ECO mode, the DCT optimizes gear selection for efficiency, upshifting earlier to achieve its class-leading fuel economy.
Hyundai has improved the synching strategy for engine startup while transitioning from EV to HEV. Previous systems saw an engine rpm overshoot while attempting to synch engine and motor speeds, Schlingmann said. This can result in some additional clutch slippage.
For this system, Hyundai minimized rpm overshoot by improving upon past software strategies, moving from a map-based strategy to self-adaptive synch logic. As an example, it rpm overshoot is detected, the software notes this and adapts for the next event. This helps to shorten the synch timing as well as dampen engine startup shock.
Additionally, first and second gears are low enough that rpm increases rapidly during launch events, allowing for lower engine speed to motor synching.
Plug-in hybrid. Hyundai will later (Q4 2017) introduce a plug-in hybrid version of the Ioniq (and Kia a PHEV version of Niro). These will incorporate a 390V, 8.9 kWh pack with a 45 kW motor, 3.3 kW on board charger and approximately 27 miles (43 km) of electric range.
The plug-in hybrid uses the same Kappa 1.6L GDI engine and the 6-speed DCT (albeit integrated with the higher power traction motor.
The larger battery pack extends rearward from the rear set, taking some of the storage space from the rear cargo area.
Both the Hybrid and Plug-in Hybrid use information and communications technology to improve fuel economy by predicting and minimizing energy for a designated driving route using precise 3D map information.
|Ioniq Electric. Click to enlarge.|
Battery-electric powertrain. The Ioniq Electric features a 28 kWh lithium-ion polymer battery for an estimated driving range of 124 miles. The electric motor has a maximum output of 88 kW (118 horsepower) and 218 lb-ft of torque mated to a single-speed reduction-gear transmission. The battery pack is forced-air-cooled and resistive-heated.
The Ioniq Electric has an EPA-estimated 136 MPGe rating, the highest efficiency rating of any electric vehicle sold in the US market.
The Ioniq Electric applies a torsion-beam rear axle, providing more space for the 28 kWh lithium-ion polymer batteries, placed below the rear seats and into the cargo area. Braking force is optimized for maximum efficiency from the regenerative braking system, helping Ioniq to maintain a steady state of charge (SOC). Regenerative braking also operates with reduced noise, using a third-generation recuperating stopping system.
Regenerative braking force can be adjusted to meet the driver’s preference and driving conditions through steering-column-mounted regenerative brake-level control paddles. An Integrated Brake Assist Unit (iBAU) and Pressure Source Unit (PSU) also contribute to quieter operation. This helps ensure ultra-low friction for maximum energy recuperation and efficiency levels.
The Electric Power Control Unit (EPCU) features a highly integrated and high-power-density inverter, which supplies power to the motor and transfors AC to DC current to charge the HV battery system.
The Ioniq Electric features Hyundai’s third generation of active hydraulic braking, noted Ryan Miller, Hyundai-Kia America Technical Center, at his presentation at SAE 2017 Hybrid & Electric Vehicle Technologies Symposium. The regenerative braking sub-system is key to the performance of electric vehicles, Miller noted, adding that Hyundai-Kia focused intently on optimizing that system for the Ioniq Electric.
The third generation is a 50% improvement over the previous generation.—Ryan Miller
The Ioniq EV also features a sophisticated heat pump system that integrates recovered waste heat from the power electronics. At 32 ˚F, the heat pump system can increase range by about 14% compared to a resistive heater, Miller said. Looking at the average power of a driving cycle, use of the heat pump system can result in a 61% reduction of load at 32 ˚F ambient, Miller said.
All Ioniq Electric models are equipped with standard Level-3 DC fast-charging capability that can take up to 100 kW. Charging the Ioniq Electric’s lithium-ion polymer battery up to 80 percent only takes approximately 23 minutes using a SAE Combo Level-3 DC, 100 kW fast charger. An integrated In-Cable Control Box (ICCB) also allows drivers to charge their Ioniq using a standard household electric socket.
Hyundai is also working with ChargePoint to further enhance the Ioniq Electric ownership experience. Ioniq owners will receive welcome kits, informing them with key information and benefits in the use of the ChargePoint charging network, and ChargePoint access cards that are easy to activate. In addition, owners will have the capability to conveniently locate ChargePoint chargers on their mobile devices using the MyHyundai/Blue Link app.
Lightweighting focus. Ioniq sought significant weight reduction targets without compromising fun-to-drive and comfort characteristics. Ioniq uses aluminum in the hood and tailgate, reducing weight by 27 lbs. compared with conventional steel and no measurable disadvantages in noise or vibration. Lightweighting also extended to less obvious areas like the cargo-screen cover. With higher usage of lightweight components and a more compact build, the cargo-screen cover is about 25% lighter than the types used in other Hyundai models.
Aerodynamics. The Ioniq sleek silhouette and simple, carefully wrought contours assist the efficient management of airflow around the exterior. Applications such as front wheel air curtains, a rear spoiler and diffuser, side sill moldings, floor undercover and a closed-wheel design all contribute to the car’s high aerodynamic efficiency of 0.24 Cd.
Additionally, the Hybrid and Plug-in Hybrid feature a three-stage active air flap (closed; 50% open; 100% open) integrated with the front grille, while a sleek, closed front fascia differentiates the Electric model. The active air flaps take into account engine coolant temperature, vehicle speed and other variables to intelligently control air inflow relative to air drag.
Pricing. The entry-level Hybrid (Blue trim)—the most fuel-efficient—carries an MSRP of $22,200. This rises to $23,950 for the SEL trim, and $27,500 for the Limited.
The Ioniq Electric starts at $29,500—without any subsidies—and increases to $32,500 for Limited trim. Both hybrid and BEV carry $835 in freight charges.
Pricing for the plug-in model will be announced closer to vehicle introduction.
The Ioniq Electric costs $7,120 less than the Chevrolet Bolt, which offers 114 miles of extra range. (More on driving comparisons between the two when drive impressions can be released next week.) The Ioniq Electric is also $1,180 less than the 112-mile-range Nissan LEAF.
Chevrolet Bolt is a great car. If you look just the starting MSRP of the Ioniq Electric versus the Bolt, you are looking at about a $7,000 price difference. That’s critical, because if you look at the average transaction price paid for a compact car, it’s in the high teens to low 20s. The Chevrolet Bolt is outside the affordability of a lot of compact car buyers. What we are hoping to do with Ioniq Electric is to make it more accessible to a majority of compact car buyers. With the Bolt you do get 114 more miles of range, but at what cost, is the question. If you look at Hyundai’s sedan models from Accent to Sonata—a two-class price jump—that price jump is less than $7,000. We hope customers are cognizant of that when shopping electric vehicles.—John Shon, Sr. Manager, Product Planning, Hyundai Motor America
(A post on driving impressions of the Hybrid, PHEV and BEV Ioniqs will be published next Monday.)