Lexus is entering the growing compact CUV segment with a model that will be available is hybrid and turbocharged versions, the 2015 Lexus NX.
Lexus said the 2015 NX debuts in two versions, the NX 200t with a turbocharged 2.0-liter four-cylinder engine and the NX 300h hybrid, which brings the brand’s number of hybrid offerings to six.
According to Lexus, the hybrid offers a real driving kick, thanks to a new transmission with a kick-down function. The racers on the team insisted on splitting the hybrid battery into two separate pods for better weight distribution, with the benefit of more efficient use of cabin space.
Both NX models are said to offer their own version of pro-active all-weather drive (AWD); each model is available with front-wheel drive or all-weather drive.
In the NX 200t, Lexus explained the available Dynamic Torque Control AWD system can instantly vary front and rear torque split between 50:50 and 100:0 for optimum traction and fuel economy. The NX 300h hybrid offers the Lexus E-Four AWD system with an electric motor to drive the rear axle when required.
Lexus explained the E-Four proactive all-weather drive system in the NX 300h hybrid uses an electric motor to drive the rear axle, while the front axle is propelled by gasoline or electric power, or a mixture of both. The sophisticated E-Four system varies torque distribution to the rear wheels, depending on driving dynamics and road conditions, and provides some rear-wheel torque at start-off to minimize chance of wheel-spin under acceleration and on slippery road surfaces.
E-Four is said to save energy and fuel, because the vehicle only uses all-wheel drive when needed. When the system detects loss of traction of the front wheels it reduces the electricity supply to the traction motor in the transaxle and increases supply to the rear-axle motor. The rear motor acts as a generator when the NX is in regenerative braking mode, increasing the amount of kinetic energy recovered.
Lexus wanted this new entry to look more sports-car than sport-utility. Meanwhile, Lexus stated the 2015 NX’s cabin is bristling with new, onboard, standard and available technology, including a Lexus-first Wireless Charging Tray for compatible phones and devices; the new Lexus Remote Touch Interface (RTI) with a touch pad; and a comprehensive Multi-information Display that features a Lexus-first G-Force meter and boost gauge.
There will also be an F SPORT version, powered by the turbocharged engine and named NX 200t F SPORT, which looks a bit sinister with its more aggressive grille and front lower bumper. Special wheels, black exterior mirrors and exclusive interior trim and front sport seats round out the package.
For its first-ever turbocharged gasoline engine, Lexus said it created an all-new engine architecture. The 2.0-liter turbocharged port and direct-injection engine uses an advanced valve control system to switch between Atkinson cycle and Otto cycle operation to optimize performance and fuel efficiency.
To minimize turbo lag, the four-into-two exhaust manifold system pairs cylinders according to their expansion or compression stroke to reduce pumping losses and eliminate exhaust gas interference. This results in improved acceleration response and wide torque band. The turbo engine produces 235 horsepower at 5,600 rpm with 258 pound-feet of torque between 1,650-4,000 rpm and up to 17psi of boost at wide open throttle. A balance shaft enhances smoothness.
Lexus tuned the 2AR-FXE 2.5-liter gasoline engine especially for use in the 2015 NX 300h. Enhancements include a water-to-oil cooler for the electric drive motor and a revised front drive reduction ratio, improving fuel economy and hill climbing.
Put your foot down on the highway, and you’ll feel the hybrid’s performance-tuned attitude, said Lexus. Its new P314 transmission provides a kick-down function for greater acceleration performance. The transmission consists of an electric motor generator and an electric drive motor linked by a double set of planetary gears. The planetary gearset simultaneously fulfills three roles: as a power split device between the generator and the front wheels; as a reduction gear for the electric motor and, when both work together, as an electronically controlled continuously variable transmission (CVT).
The transmission is said to offer sequential shift which allows maximum power to be delivered on demand and increases engine braking when decelerating.
The NX 300h employs Lexus’ electronically controlled braking system known as ECB-R to provide cooperative control of stopping power and regenerative braking while saving on vehicle weight.
As explained earlier, the hybrid battery pack is said to be split into two modules, each weighing 44 lbs. and located on each side of the rear seat, improving space efficiency and also center of gravity for enhanced car control. The company said this battery pack is one of the lightest among Lexus hybrids.
Package efficiency improvements listed by Lexus include downsizing the Power Control Unit (PCU) with a double-sided inverter cooling system. The PCU inverter boosts direct current (DC) voltage from the HV battery and converts it to alternating current (AC) to drive the electric traction motor and, where applicable, the rear-drive E-Four electric motor. It also converts AC from the generator to DC for storage in the hybrid battery.
Lexus added the PCU also includes a DC-DC converter to provide 12-volt power for vehicle ancillaries, including the lights and audio system. The DC-DC converter saves fuel, because the gasoline engine does not have to drive a separate alternator. The entire 2WD PCU is installed in the engine compartment. In the AWD model, the inverter and DC-DC converter are located at the rear of the vehicle.
Lexus continued by stating the 2015 Lexus NX makes extensive use of low energy consumption LEDs for front and rear lights. Two types of LED headlights are available. The NX 200t uses LEDs for the low beams and halogen bulbs for the high beams. Available for NX 200t and standard for NX 300h, the same LED light source provides the high beam and the low beam, yielding uniform light distribution with no chromatic variation. A two-color (black and clear) molding method gives the thick-walled lens a crystal glass appearance even when not illuminated.
Price and fuel consumption information are expected to be released soon.