Hyundai unveiled the 2017 Ioniq at the Geneva Show, a car only available with an electrified powertrain. There will be three variants of the car, offering a conventional parallel hybrid, plug-in hybrid and battery electric drive.
Hybrid and plug-in versions use the new Hyundai/Kia Kappa 1.6-L direct injection gasoline engine announced in October 2015. The long-stroke engine uses Atkinson Cycle principals and cooled exhaust gas recirculation (EGR) to achieve a claimed 40% brake thermal efficiency. According to company engineers, the engine's EGR rate exceeds 20%, with a 98% cooling efficiency for the EGR cooler and a 56.9-ms response time for the EGR valve. These three features are said to provide a claimed 3% gain in fuel economy.
Hyundai claims that fuel savings are boosted by setting separate thermostat cooling temperatures for the block and cylinder head, set at 105°C and 88°C, respectively.
Other details of the Kappa engine include six-hole laser-drilled GDI injectors and a 200-bar fuel system pressure. The engine is rated at 77.2 kW (104 hp) with peak torque of 147 N·m (108 lb·ft).
3 electrified powertrains
In the hybrid and plug-in hybrid variants, the engine is coupled with a 6-speed dual clutch automated transmission and the slim electric motor/generator is conventionally sandwiched between the engine and clutch. The motor is rated at 32 kW (43 hp) and produces peak torque of 170 N·m (125 lb·ft).
Electric power is supplied by a lithium-ion polymer battery of 1.56 kW·h capacity. Hyundai claims the Ioniq can achieve a maximum velocity of 185 km/h (115mph). No official emissions and fuel consumption figures are currently available, but Hyundai claims target CO2 emissions of 79 g/km or lower.
The same basic architecture is used for the plug-in hybrid, but both battery and electric motor are uprated. Hyundai claims battery capacity of 8.9 kW·h, using lithium-ion polymer chemistry again. The electric motor is rated at 45 kW (60 hp) and Hyundai claims range greater than 50 km (31 mi). CO2 emissions are said to be as low as 32 g/km.
The Ioniq EV also relies on a lithium-ion polymer battery pack, rated at 28 kW·h. The battery can be charged from a regular domestic power point or fast charger. Hyundai claims that using a 100-kW fast charger, the battery can be charged to 80% capacity in 24 min. The motor is rated at 88 kW (118 hp) and drives the front wheels through a single-speed reduction gearbox.
The motor in all three Ioniq variants is of the permanent-magnet synchronous type, with the thickness of the electrical sheet steel core components reduced by up to 10%, claims Hyundai. Rectangular-section copper wire is also used to improve efficiency.
In all three models, the battery is located under the rear passenger seat. Battery electric variants carry more batteries under the spare wheel well. Up to 750 L of cargo space is said to be available in hybrid models and up to 650 L in plug-in and battery electric models.
Aero and mass reduction measures
Hyundai states a 0.24 Cd drag coefficient for the Ioniq. To achieve this, the development team used a variety of techniques including front wheel air curtains, rear spoiler and diffuser, molded rocker panels, a cover beneath the car and closed wheel designs.
All Ioniq models are fitted with low rolling resistance Michelin tires on 15-, 16- or 17-in rims. Hybrid models with 17-in wheels are fitted with silica tires, which can combine good grip characteristics with low rolling resistance.
Weight reduction measures include the use of aluminum in the hood and tailgate, reducing weight by 12.3 kg (27 lb) compared with using steel. Other weight saving measures include the roller cover over the cargo space claimed to be around 25% lighter than similar covers in other Hyundai models.
Aluminum is used extensively in the suspension components, reducing weight by around 10 kg (22 lb). Each front lower arm weighs a claimed 2.3 kg (5 lb) less with a 3.57-kg (8-lb) weight saving for each rear lower arm. The chassis is made from a claimed 53% of high-strength steel to improve rigidity and limit weight.
Two different rear suspension arrangements are used. Battery electric models use a torsion beam rear axle to provide greater space for the battery pack. Hybrid and plug-in models are fitted with a multi-link system.