New Car Tech: 2014 Mercedes-Benz S-Class
Even though the new S-Class could have been first out of the gate, Mercedes decides to take a pass on autonomous driving, for now.
"The car would do it [autonomous driving] today," said Jochen Haab technical support manager, "we have had test cars doing that, but what happens if a child steps out into the street and the radar misses it?"
English in the simulator
Distronic Plus Steering Assistance System
It is Mercedes' new Distronic Plus steering assistance system that gives the forthcoming S-class< autonomous driving potential. It has a lane-guidance capability, which locks on dotted white-lane markings, or the car in front on highways at speeds up to 124 mph on turns of less than 15 degrees. But while that and other systems would allow the S-class to maintain its distance from the car in front, braking to a complete halt, restarting from stationary and even stopping for cross traffic, the driver has to keep hold of the steering wheel. If the system detects that he isn't imparting torque to the wheel rim then it will warn after 10 seconds and switch the system off after 15.
Driving the simulator
The sort of self-driving envisioned for the new S-class would "have happened at certain places and at certain speeds," admits one expert. We understand that it would have been at low speeds of less than 24 mph only on congested highways where all the traffic is going in the same direction, at similar speeds, with no pedestrians and no cross junctions. "For sure there was a debate about it," admits Haab, "but what if you have an accident?"
He says that while the product liability issues and potential for crippling legal suits against Mercedes were major deterrents to launching the world's first self-driving car, there were other, equally important constraints.
"We would have to have full data recording on board," said Haab, "and would our customers be willing to accept such a system?"
English being watched in the simulator
In addition there were issues about the technology and its potential to cover all eventualities. "Can the car detect whether it can drive autonomously for the next 20 seconds?" asked Haab. "Probably not at the moment."
At the heart of the Distronic Plus steering system is the new 360-degree sensing systems, comprising a bewildering range of six separate radar systems, a stereoscopic camera, 12 ultrasonic sensors, which can detect close objects and four additional cameras all around the body. The stereoscopic camera recognizes the speed and trajectory of moving hazards up to 164 feet away, which means cross-traffic hazards are detected and the twin-stage infra-red detection system sees those hazards in the dark as well. Complex algorithms identify and differentiate humans and animals and reacting accordingly, braking for both but flashing a headlamp warning at humans only.
New S-class sensor range
Most industry experts reckon limited self-driving capabilities will be introduced within the next few years. General Motors' division has a self-driving system on test known as "Super Cruise", capable of fully automatic steering, braking and lane centering on highways under certain conditions and according to Nady Boules, GM's director of electrical and controls integration research, autonomous driving cars will go on sale within the next ten years.
We drove the system on Mercedes-Benz's driving simulator at its research department at Sindelfingen in Germany. This massive installation gives a computer-generated 360-degree view around a real car installed in the hydraulically powered pod, which has a 40-foot base on which it is able to react realistically to acceleration, braking and cornering inputs. In a short urban `drive', the sensor systems picked up all the artificial hazards (pedestrians running into the road, cars crossing intersections against the light) that were thrown in its way, but then it would have been extraordinary if they hadn't. Even Mercedes-Benz engineers admit, however, that there are some `holes' in the barrage of systems. Fog poses an almost impenetrable barrier to the sensor systems and the computer algorithms are still far from perfect.
World's First All-Light Emitting Diode Car
Mercedes is also claiming that its new car will be the world's first bulb-less motorcar, although automobile historians will know that simply can't be true as Karl Benz's 1886 Benz Patent Motorwagen appeared a full 13 years before Thomas Edison first patented the electric light bulb. What the S-class is, however, is the world's first all-Light Emitting Diode car, with all its exterior lighting and interior illumination courtesy of LED sources.
LED rear lamps in low-intensity mode
It also has what seems like the world's most complicated and sophisticated headlamps, which incorporate an optional motorized masking system for the high-beam headlamps so drivers can keep the high beams on virtually all the time. Developed in collaboration with Automotive Lighting, Bosch's old lighting division now owned by Magnetti Marelli, the optional headlamp system is called Adaptive Highbeam Assist Plus and each unit is expected to cost about the same as a current Bi-Xenon headlamp.
New S-Class LED headlamps
Using it stereoscopic camera and recognition algorithms, the new Mercedes recognizes either on-coming headlamps, or the tail lamps of vehicles ahead. It then deploys a moving motorized masking system, which actively vignettes those light sources to prevent their drivers being dazzled and allow the S-class's main beams to be left on all the time. Three motors are used in each headlamp unit to allow this high-beam system to operate: one each for vertical and horizontal positioning and a third motor, which actively changes the light distribution.
Vignetting system of new LED headlamps
Mercedes claims its LED units require 34 watts per vehicle to produce the same light output as that 120 watts of Halogen lighting or 84 watts of Xenon lighting, saving up to 0.05 liters of fuel per 100km.
The S-class uses three main single-chip lighting units at the front: a 10 LED low beam and cornering unit, a 4-LED high beam unit, 10 daylight running LEDs and 6 for each turn indicator. The infra-red night vision system uses its own LED light sources to `light up' animals and humans when they have been identified at a long distance.
All these LED units are sealed in a single, common main-beam unit in which the LEDs' heat is re-circulated, which means no separate heating is required for the main glass. The system also dims the rear brake lights and turn indicators at night and even more when stationary to prevent dazzling drivers behind.
Active seat belt
There are also innovative rear seat-belts, which form part of the Pre-Safe system which prepares the car in the event of a crash. In this case the rear belt goes through its normal pre-crash tightening procedure, but then inflates the belt itself on impact. This jams the belt in the latch, which has the effect of allowing the lower part of the belt to remain tight, but the diagonal part of the belt to be progressively released on impact to help mitigate upper chest injuries. It also disperses forces over a wider area of the chest for the same effect.
