At CES Asia 2015 in Shanghai, Audi is showcasing a piloted driving technology study version of its new R8 e-tron battery-electric sports car, introduced earlier this year at the Geneva show. (Earlier post.) Audi is also featuring a piloted driving version of its A7 Sportback. (Earlier post.)
The R8 e-tron—340 kW (456 hp) of power, acceleration from 0 to 100 km/h (62.1 mph) in 3.9 seconds, and a driving range of 450 km (280 miles)—is based on the multi-material Space Frame of the second-generation production R8. The piloted driving technology study integrates a range of future technologies for lightweight design, high-performance drive systems and functions for piloted driving.
Piloted driving in China: the Audi strategy. Audi so far has focused its developments in piloted driving on the US and Europe. Chinese road traffic poses its own special challenges for automated driving functions, the company said. This is attributable in part to differences in driving behavior, but it is also due to the structure of the road network, in which urban freeways and regular streets are laid out directly above one another over long distances.
To offer driver assistance systems that are appealing to Chinese drivers as well, Audi launched a project at its R&D Center in Beijing in cooperation with Tongji University in Shanghai. The researchers developed solutions for specific local driving situations in China. The project is part of a strategy for solving specific local challenges and testing them in local road traffic. Audi has been successfully pursuing this strategy in the US for many years. The brand’s appearance at CES Asia represents the initial results of the company’s collaboration in China.
R8 e-tron piloted driving. The R8 e-tron rear car body module is made of carbon fiber reinforced polymer (CFRP) integrating the luggage compartment, which extends the frame structure. The walls of the luggage compartment shell are corrugated, so that they can absorb extreme amounts of energy with little material weight in case of a rear-end collision.
Due to specific modifications made to the outer shell and wheels, the Audi R8 e-tron piloted driving attains a low Cd value of 0.28. Its front end and sideblades feature e-tron specific lighting solutions.
The T-shaped 92 kWh battery pack (up from 49 kWh in the first generation) is structurally integrated into the center tunnel and behind the occupant cell; its low center of gravity further boosts the already excellent driving dynamics of the R8 e-tron piloted driving. The high-voltage battery is based on a new lithium-ion technology that has, for the first time, been specifically designed for the drive system of an all-electric vehicle, Audi says.
Although the pack energy capacity has grown from 49 kWh to approximately 92 kWh, the vehicle packaging is the same, due to optimized space utilization and improved battery cell technology. Audi produces the high-voltage battery itself.
The R8 e-tron piloted driving achieves an electric range of 450 kilometers (279.6 mi) instead of a previous 215 kilometers (133.6 mi) due to an increase in its energy density from 84 Wh/kg to 154 Wh/kg and several other modifications. The high-performance sports car has the Combined Charging System (CCS) on board, which allows charging with direct and alternating current. With this system, the customer can charge the large battery in significantly less than two hours.
The two electric motors each output 170 kW of power and 460 N·m (339.3 lb-ft) of torque to the rear axle. The R8 e-tron’s electronically-governed top speed is 210 km/h (130.5 mph) or 250 km/h (155.3 mph), depending on the car’s tires. Intelligent energy management and an electromechanical brake system enable high energy recuperation rates. Targeted torque vectoring—needs-based distribution of power transmission between the rear wheels—ensures maximum stability and dynamism.
The R8 e-tron piloted driving technical study is equipped with all of the functions of piloted driving. Data is acquired from the interplay of an array of sensors: a new type of laser scanner, several video cameras, ultrasonic sensors and radar sensors at the front and rear. Based on signals from these sources, the central driver assistance control unit (zFAS) (earlier post) computes a comprehensive picture of the vehicle’s environment.
Audi can build the R8 e-tron in handcrafted quality to meet special customer requests. The company uses its high-performance electric sports car primarily as a high-tech mobile laboratory.
Piloted driving Audi A7 Sportback. Journalists at CES Asia can ride along in the piloted driving Audi A7 Sportback prototype over an approximately 15 km (9.3 mi) route through Shanghai that starts and ends near the trade fair site.
The test vehicle utilizes various production and near-production sensors. The long-range radar sensors of the adaptive cruise control (ACC) system monitor the zones in front of the car. A near-production laser scanner is mounted in the Singleframe grille. The sensors provide redundant information on stationary and moving objects they detect during the piloted drive. A high-resolution video camera by partner Mobileye, a prototype for a future generation of such devices, offers a wide-angle view in front of the car.
The function for piloted driving in traffic jams, which Audi is currently developing, is based on radar-supported adaptive cruise control (ACC) including traffic jam assist that will launch on the market in the new Q7. The system offers relief to drivers in dense highway traffic by handling steering tasks between 0 and 60 km/h (37.3 mph), and it accelerates and brakes autonomously. When the traffic jam pilot reaches its specified limits, such as when the traffic jam resolves itself, or the end of a divided highway is reached, the system prompts the driver to take control of the vehicle again. If the driver does not do this, the system safely brings the car to a stop.
In the future system for piloted driving, the radar sensors will remain an important component of the sensor array. They will acquire information from the zone in front of the car as they do today. A video camera with a wide angle lens detects the lane markings as well as pedestrians and objects, such as other vehicles and guard rails. Up to twelve ultrasonic sensors are used to monitor the immediate space around the car.
A new member of the sensor array is the laser scanner – it delivers highly precise data on objects at a distance of up to 80 meters (262.5 ft). Its laser diode emits nearly 100,000 infrared light pulses per second that are invisible to the human eye.
The control unit computes a surroundings profile from the light reflections. The laser scanner covers a range of 145 degrees on four vertical levels. Because of its wide aperture angle, it can detect vehicles that are merging in front of the car very early on. It also operates in the dark without any limitations. It can detect any objects – including those that exhibit a uniform pattern, such as fences, or objects that do not have any visible texture such as white walls.