New Leaf EV previews Nissan's future autonomous drive technologies
Earlier this week, Nissan unveiled its second-generation Leaf EV (electric vehicle) with an improved driving range and a lower U.S. $29,990 starting price. The new model features a 150-mi (242-km) driving range, aerodynamic exterior, roomy interior, and advanced technologies including ProPILOT Assist and e-Pedal. It is the first step in the relaunch of Nissan's EV platform and will be followed in model year 2019 with a higher-performance version with increased motor power and battery capacity.
José Muñoz, Chief Performance Officer, Nissan Motor Co., Ltd. and Chairman, Nissan North America, Inc., unveiled the 2018 Nissan Leaf at a media event at Las Vegas' Thomas & Mack Center, following the Leaf's global launch in Tokyo. “The value equation for the new Leaf is even stronger than ever before—beginning with a starting MSRP under $30,000,” said Muñoz. “That's a lower price than the Leaf in the market today and it includes more power, range, and technology—all wrapped in a beautiful new exterior and interior design."
Nissan hopes the redesign can help accelerate its pioneering EV sales effort. To date, Nissan has sold more than 112,000 Leafs in the U.S. and more than 283,000 globally—and spawned a Renault spinoff.
The product development team for the second generation of the pioneering Nissan electric vehicle focused on improved power, range, refinement, comfort, and convenience—and incorporation of the global Nissan Intelligent Mobility initiative that focuses on how the brand’s vehicles are “driven, powered, and integrated into society.” Headlining the intelligent driving technology are ProPILOT, ProPILOT Park, e-Pedal, and the Nissan Safety Shield.
The Leaf’s new ProPILOT Assist—Nissan's advanced single-lane driver assistance technology—helps ease driver workload by reducing the amount of driver acceleration, steering, and braking input needed under certain driving conditions. While it is a "hands-on" system, it previews Nissan's ongoing development of future, more autonomous drive technologies.
ProPILOT is designed for driving on the highway in traffic. When switched on, it can automatically control the distance to the vehicle in front using a speed preset by the driver between about 30 and 100 km/h (19 and 62 mph). It also helps the driver steer and keep the vehicle centered in its lane. If the car in front stops, the system automatically applies the brakes to a full vehicle stop if necessary. When traffic restarts, the car resumes driving after the driver touches the switch again or lightly presses the accelerator.
ProPILOT Park helps automatically control accelerating, braking, handling, and shifting to guide the car into a parking spot, activation requiring three steps. It combines advanced image-processing technology using four high-resolution cameras and information from 12 ultrasonic sensors around the car. All inputs for various parking maneuvers, such as parallel parking, are automated. The system can automatically identify a parking space around the car.
The new Leaf is also equipped with a set of Safety Shield advanced driver assistance systems including intelligent lane intervention, lane-departure and blind-spot warning, intelligent emergency braking, traffic-sign recognition, rear cross-traffic alert, intelligent around-view monitor with moving-object detection, and emergency assist for pedal misapplication.
The e-Pedal, similar to offerings from other EV makers, allows the driver to use the accelerator pedal alone to start, accelerate, decelerate, stop, and hold the car. No brake pedal is needed, with deceleration rates up to 0.2 g, except for aggressive braking situations. Studies by Nissan in Japan, Europe, and the U.S. have shown that the e-Pedal significantly reduces the number of brake applications especially in heavy traffic. It lets drivers use a single pedal for more than 90% of driving needs.
“Drivers of the new Nissan Leaf will quickly come to love the e-Pedal, as it makes the usual experience of urban driving far smoother and more fluid, and less demanding,” said Hiroki Isobe, Chief Vehicle Engineer.
The electric powertrain offers improved energy efficiency and increased output. Compared with the previous generation car, EM57 electric traction motor power output is up 38% to 110 kW from 3283 to 9795 rpm and maximum torque is increased 26% to 320 N·m (236 lb·ft) from 0 to 3283 rpm. Driving range is increased by the car’s new 40-kW·h lithium-ion battery pack to 400 km (250 mi) by Japanese (JC08) standards—much greater than the 150-mi (240-km) range by U.S. measurements. Zero to full charging time is normally 16 h at 3 kW or 8 h at 6 kW, with 80% under quick charging needing 40 min.
The new battery design adds energy-storage capacity while occupying the same dimensions as that of the previous-generation car. Improvements to the individual cell structure of the laminated lithium-ion battery cell results in an impressive 67% increase in energy density versus the 2010 model. Enhanced electrode materials with revised chemistry also contribute to higher power density and greater battery durability on charge and discharge.
Nissan engineers enhanced the car’s chassis for better stability. Heavy components, including the battery, are placed closer to the center of the body, helping to achieve smaller yaw moments of inertia for improved directional stability and smoother cornering. Power steering goals of more linear feel and enhanced road-surface feedback were accomplished with a software upgrade, new control logic working in conjunction with the steering angle sensor, and a 10% increase in steering torsion bar stiffness.
Though inspired by the IDS Concept car from the 2015 Tokyo Motor Show, the production car hews closely to current conventional Nissan product design, with cues such as a V-Motion grille, “boomerang” light signature, and floating roof. A clear-blue 3D mesh pattern inside the V-Motion grille and other blue accents are a nod to EV-uniqueness.
Key Japanese-model dimensions are 4480-mm (176.4-in) length, 1790-mm (70.5-in) width, 1540-mm (60.6-in) height, with a 2700-mm (106.3-in) wheelbase. Curb weight is 1490-1520 kg (3285-3350 lb), and gross vehicle weight is 1765-1795 kg (3890-3960 lb).
Contributions to the car’s 0.28 drag coefficient are the underfloor, a diffuser-type rear bumper that also contributes to zero lift, and aero-design wheels. The angle of the front port is reconfigured to more easily and comfortably connect the electric charger.
Along with less drag, aerodynamic upgrades and exterior refinements result in wind-noise reduction, among other NVH enhancements. Other noise reduction measures include optimization of the redesigned inverter’s structural rigidity, a noise-isolating cover on top of the power delivery module, and a quieter electric motor.
The interior design is also brought more into line with Nissan convention, but with vibrant blue stitching marking it as a Nissan EV. An analog speedometer is used in conjunction with a multi-information display. The center display is for audio and navigation systems, and it displays Safety Shield status, the vehicle’s state-of-charge, and a power gauge. NissanConnect features include continuously updated information on location and operating hours of free charging stations and charging station availability. Apple CarPlay has been added in cars equipped with navigation.
Interior dimensions of the five-seater remain essentially unchanged. However, the rear cargo area has been redesigned to provide increased luggage space of 435 L, according to VDA measurement methods, and a squarer space that can now accommodate two large suitcases or three medium-sized, airline carry-on suitcases.
The new Leaf goes on sale October 2 in Japan, with deliveries in January in the U.S., Canada, and Europe. It will be sold in more than 60 markets worldwide. Nissan plans to start full production of the car by the end of calendar year 2017 at Nissan's Vehicle Assembly Plant in Smyrna, TN, and Nissan Motor Manufacturing (UK) Ltd. in Sunderland, UK, joining the Oppama Plant in Japan in producing the Leaf.