In 2005, Mercedes-Benz unveiled its new top-of-the-range model, the S-Class W221 series, at the IAA in Frankfurt/Main. The saloon built in Sindelfingen went on sale at dealerships and sales partners in the autumn of 2005. As every S-Class before, this S-Class incorporated technical innovations into its standard equipment, enabling this series to continue the position the S-Class had gained as role model and trendsetter in automotive engineering. Innovative safety and the highest driving comfort were always the hallmarks of the S-Class. Like its predecessor, the new saloon set standards with its agile handling and provided an exceptional driving experience with its new, more powerful engines. The new S-Class replaced the previous W220 series, which, with almost 500,000 vehicles, was the best-sold saloon in the world.
Compared with its predecessor, the new top-of-the-range model from Stuttgart had grown in every respect. The body was available in two lengths: 5076 and 5206 mm, which was respectively 33 and 43 mm longer than the predecessor. The wheelbase was extended by 70 and 80 mm to 3035 and 3165 mm respectively. The body was also 16 mm wider and 29 mm higher. These new dimensions created conditions for an interior makeover that provided premium comfort for all of the occupants.
Some twelve technical innovations became part of the standard equipment in the S-Class 221 - from the Brake Assist BAS PLUS with radar sensors; the drive-dynamic multi-contour seat with massage function; the Night View Assist with infrared technology; the enhanced COMAND system; the preventative PRE-SAFE® occupant safety system with additional functions; through to the Active Body Control, ABC.
The ride comfort was increased by equipping the body with the enhanced air suspension AIRMATIC, which Mercedes-Benz combined with the Adaptive Damping System ADS, which adapted the damping force according to the requirements and the condition of the road, while taking the driving style and the saloon's load into account. Within only 50 milliseconds, the system adjusted the damping force on each wheel according to the situation. The functionality of the ADS was further enhanced with degressive damping characteristics, which enabled a better distribution of the damping forces between the compression and rebound stage and contributed considerably to the saloon's agile handling. The system recognized the condition of the road, which it also took into account when adapting the damping force thanks to an improved calculation method that was more accurate than before.
Another unique feature in the S-Class 221 series was the ‘S/C/M' button in the centre console used to switch between the three driving programmes ‘Sport', ‘ Comfort' and ‘Manual'. Changing the driving programme automatically changed the settings for the body, the height and the transmission. In ‘Manual', the automatic transmission was operated with paddles in the steering wheel. If the S-Class was travelling on a bad road that required more room between the body and the road, all the driver had to do was press a button and the body rose by 30 mm. From 120 km/h in the ‘Sport' programme, the body was automatically lowered by 20 mm to improve the vehicle's driving dynamics, aerodynamics and fuel consumption.
The Active Body Control ABC (standard in the S 600) was considered a milestone in automotive engineering and was further enhanced in the S-Class 221 series. The active body was equipped with four microprocessor-controlled spring struts with plunger cylinders that almost entirely compensated roll, pitch and vertical movements. The computer analyzed information it received from different acceleration sensors about a particular driving situation and compared it with the information in the pressure sensors in the spring struts and the level sensors in the control arms. The system then calculated the control signals, which were converted by servo-hydraulic valves in the front and rear axle into exact oil flow rates. Oil flowing into the plunger cylinders moved the base of the steel springs that were integrated in the spring struts thus creating enough energy to counter the body's movements. The constant hydraulic pressure of up to 200 bar enabled the ABC to respond to body movements in a fraction of a second. The system controlled body vibrations in a frequency range up to 5 hertz that are typically caused by rolling and vertical movements on uneven road surfaces, a strong side inclination when cornering, and pitching when braking. The higher frequency vibrations were handled by passive twin-tube gas-charged shock absorbers. But the main advantage of the second-generation ABC was the improved driving performance when body movements were reduced. This propelled the S-Class into a new dimension in dynamic driving, while adding additional comfort. The body's roll angle in a dynamic driving manoeuvre was reduced by more than 60 percent, namely from 3.1 to 1.2 degrees. When corners were taken at a high speed - for example, on a slip road - the second-generation ABC reduced the roll angle to just 0.75 degrees. That was more than 60 percent less than in the previous W220 series.
Mercedes-Benz had enhanced and improved proven safety systems such as Brake Assist and PRE‑SAFE® for the S-Class 221 series. The high-tech innovations played an essential role in collision prevention, occupant safety and driver assistance. The new Brake Assist (BAS) PLUS used radar to detect vehicles travelling ahead and warned the driver if he/she was approaching the vehicle too quickly or there was not enough distance between the two vehicles. As soon as the system detected a potentially dangerous situation, it calculated the best brake assist force and applied it - even if the driver didn't press the brake pedal hard enough. This helped reduce the number of collisions considerably.
The anticipatory BAS PLUS was part of the DISTRONIC PLUS Package. In addition to the 77-gigahertz long-range radar in the adaptive cruise control, it used a brand new 24-gigahertz short-range radar. The systems complemented each other: While the DISTRONIC radar was positioned at an opening angle of 9 degrees that enabled it to scan three motorway lanes up to a distance of 150 m, the new 24-gigahertz radar was positioned at an angle of 80 degrees enabling it to scan directly around the vehicle up to a distance of 30 m.
The area the adaptive cruise control DISTRONIC PLUS covered was also wider compared with the previous series: It now ranged from 0.2 to 150 m. The electronic controls analyzed the information from both of the radar systems and calculated the shift operations for the engine, automatic transmission and the brakes that were necessary to maintain the correct distance. The range in which the speed could be controlled was also increased: From previously 30 to 180 km/h to 0 to 200 km/h. This meant that When traffic slowed down, DISTRONIC PLUS would automatically decelerated until the vehicle came to a standstill and then accelerated the saloon to the requested speed, providing the traffic situation so allowed. To start the vehicle automatically, all the driver had to do was activate the DISTRONIC lever on the steering wheel or briefly press the accelerator.
Mercedes-Benz combined BAS PLUS with the equally unique occupant safety system PRE-SAFE®, which had even more safety features in the S-Class 221 series. PRE‑SAFE® detected potentially dangerous situations before they arose: When the rate of deceleration exceeded a certain level or there was a risk of skidding, the system preventatively tightened the front seatbelts and pumped air into the multi-contour seats that enclosed and supported the driver, the passenger and the rear occupants. Combining the new BAS PLUS and PRE-SAFE® further increased occupant safety. Mercedes-Benz was the world's first and only automobile brand to introduce such a comprehensive safety system that self-activated in the event of an impact.
With the brand new Night View Assist, which premiered in the S-Class, Mercedes-Benz made yet another contribution towards reducing the risk of night-time collisions. The system used infrared light, which is invisible to the human eye and does not dazzle oncoming traffic. Two infrared headlights illuminated the road and clearly increased visibility when driving with dipped beams. As soon as Night View Assist was activated, the display in the centre of the instrument cluster automatically changed and displayed the images captured by the infrared camera installed on the inside of the windscreen. The large 8-inch display was in the driver's main field of vision and could be used in the same way as the speedometer or cockpit instruments. By regularly scanning the infrared images, the driver could assess the situation ahead of the vehicle and adjust his or her driving style accordingly. When the system was switched on, the usually round speedometer was displayed as a horizontal bar at the bottom of the display.
Mercedes-Benz engineers had tested the functionality of the infrared system in the field before it was put into operation. During test drives with Bi-Xenon dipped beams and the new Night View Assist, drivers noticed obstacles on the road a lot earlier when driving with the infrared system switched on. They saw test dummies dressed in light clothes on average at a distance of approximately 210 m and thus 41 m earlier than with the Bi-Xenon dipped beams. The system was even more effective when pedestrians in dark clothes walked down the road. With the Night View Assist switched on, drivers recognized the test dummies at a distance of approximately 164 m, but only at about 72 m with the Bi-Xenon dipped beams. This equates to 125 percent safety.
In the autumn of 2007 Mercedes-Benz made switching lanes much safer with the introduction of the new Blind Spot Assist. The new assistant used six short-range radar sensors positioned in the front and the rear bumpers from where they monitored the area beside and behind the vehicle. They covered the infamous blind spot, the area that drivers cannot see in their door mirrors. As soon as the system detected another vehicle in the warning zone, a red warning light would illuminate in the door mirror and notify the driver that it was potentially dangerous to change lanes. If the driver ignored the warning and activated the indicator, the red signal in the mirror would start flashing and an audible warning signal was emitted.
The ‘Cockpit Management and Data System' - in short, COMAND - was presented with a new design and even more functions. The idea was for the occupants to develop a harmonious relationship with their S-Class right from the start. A key feature of the new COMAND generation was quick access to frequently used functions. That's why the system had a redundant design: Based on his or her habits, the driver could control the radio, TV receiver, CD/DVD changer, telephone and navigation with the conventional buttons, the paddles on the multifunction steering wheel or by using the enhanced COMAND system. The direct select buttons on the centre console were positioned ergonomically so the driver could reach them without having to look. In addition to the familiar telematic and audio devices, a number of vehicle functions that previously had their own buttons were integrated in the system. The new COMAND Controller was the main control element on the centre tunnel. The controller was used to select the main and sub-menus and activate functions. The telephone keypad was concealed underneath the lid of the hand rest. The COMAND's large, tiltable colour display was at the same height as the instrument cluster making it easier to see by both driver and passenger. COMAND came with radio, CD/DVD player and a PCMCIA card reader, and was optionally available with a Pan-European navigation system, whose data were stored on a hard drive. It calculated the router faster than ever.
The steering wheel and instrument cluster were the heart of this new control concept. They integrated all of the information and functions that the driver needed during the journey. The 8-inch high-definition colour display (16:9) with the latest TFT technology was the central component. It displayed a graphically animated speedometer, whose indicator was partially overlaid to highlight the information in the centrally located main display. Depending on the interior equipment, the graphic computer displayed a line of control text at the bottom of the TFT screen that contained up to seven main menus and a variety of sub-menus for individual settings, notifications and control functions. The control elements on the multifunction steering wheel were designed so that the driver could quickly select the settings and functions: The previous paddles were replaced with a thumb-operated circular, illuminated five-way-paddle. Selections and settings were confirmed by pressing the ‘OK' button in the middle of the paddle. Pressing ‘Return' took the user back a menu level. The main control area also contained the redesigned levers on the steering column, which were within the driver's immediate reach and field of vision. As before, the DISTRONIC PLUS cruise control (optional), windscreen wipers, indicators, steering wheel heating (optional) and the position of the steering column could be programmed. True to the belief that ‘ everything has its right place', the control to set the desired vehicle distance was integrated in the DISTRONIC lever. In the previous version, it was in the centre console.
In the S-Class 221 series, the driver could also use LINGUATRONIC (optional) to operate the telephone, audio system and the navigation system. LINGUATRONIC was activated by pressing a button on the steering wheel. A few words were all that were needed to search for or store a radio station, skip to the next track on a CD or programme the navigation system with the desired destination. LINGUATRONIC enabled the driver to remain focused on traffic.
Passengers could adjust the S-Class' new seats to their personal level of comfort. Electrically adjustable 12-way front seats with lumbar support were part of the standard equipment. Heated and actively ventilated luxury seats and multi-contour seats (front and rear) were optionally available, as were drive-dynamic multi-contour seats in the front. Mercedes-Benz had refined the multi-contour technology: The front seats were now equipped with eleven air cushions that enabled the occupant to adjust the seat contour to his or her liking. New piezo valves in the air chambers worked faster than the previous technology, which noticeably improved the drive-dynamic function of the multi-contour seat: Depending on the steering angle, lateral acceleration and the speed at which the vehicle was travelling, the piezo valves would inflate or deflate the lateral air chambers in seconds, giving the driver and the passenger even better side support. The drive-dynamic multi-contour seats were also equipped with seven separate air chambers in the lumbar region that would inflate and deflate according to a pre-programmed pattern, giving the passenger a pleasant, rolling back massage. The massage stimulated the muscles and the blood circulation, and helped prevent fatigue. The multi-contour seats for the driver and the front and rear passengers were awarded the seal of approval from the ‘Campaign for Healthy Back' by the German association ‘ Aktion Gesunder Rücken'.
The high level of comfort and the modern technology in the S-Class 221 series relieved fatigue and had a positive effect on the driver's attention span. This was confirmed by scientific comparative tests between the S-Class and competitor models over a distance of 500 km during which the typical stress indicators were recorded. Under the same driving and traffic conditions, the heart rate of the drivers in the Mercedes-Benz was on average up to 6 percent (or five beats per minute) lower than the values measured in the comparison vehicles. According to the experts, this was a clear indication that the new top-of-the-range model clearly reduced stress caused by driving. Drivers had a higher attention span and were able to react faster and better to potentially dangerous situations because they didn't have to use their reserves. The high level of comfort in the S-Class not only contributed to the wellbeing of the occupants, but also to road safety.
The bodyshell also played an important role in increasing safety, comfort, dynamic, durability and other key features of the S-Class The body's static torsional stiffness - an indicator of safe and easy handling - improved compared with the previous series by approximately 12 percent. Some 50 percent of the components in the bodyshell were made of lightweight high or super-high tensile high-tech alloys. Mercedes-Benz used aluminium for the bonnet, front wings, doors, boot lid and other components. High-quality recycled materials and renewable raw materials played an important role in the S-Class' material balance. Natural materials were used to make 27 components with a combined weight of approximately 43 kg. This was 73 percent more compared with the previous series.
The new luxury saloon was the first automobile in the world to obtain an environmental certificate, confirming the company's green product development philosophy, which had made clear advances in key environmental areas. For example, the exhaust emissions of the S 350 were up to 85 percent lower than required by the applicable Euro 4 emission standards. The integration of environmental protection in the development process (Design for the Environment) for the S-Class was certified by the certifying body of TÜV Management GmbH in Munich. The assessors also examined the environment-related data and statements in the product information for the new S-Class.
Mercedes-Benz offered the S-Class 221 series in two body and four engine versions. The S 350 and S 500 petrol-engine models were introduced in the autumn of 2005, and supplemented from the first quarter of 2006 with the six-cylinder S 320 CDI diesel engine and the S 600 V12 saloon. The output generated by the engines ranged from 173 kW (235 hp) to 380 kW (517 hp). The V6 and V8 models were optionally available with a 130 mm longer wheelbase; the S 600 was only available with a long wheelbase.
All of the engines for the new S-Class had been developed from scratch or enhanced. Compared with the previous series, they had up to 26 percent more output, 15 percent more torque and consumed 9 percent less fuel.
A new eight-cylinder in the 221 series was unveiled. With a displacement of 5.5 litres and an output of 285 kW (388 hp), it was one of the most powerful engines in its displacement class. Compared with the previous V8 engines, maximum torque increased to 530 Nm and was now generated between 2800 and 4800 rpm. The new S 500 accelerated from 0 to 100 km/h in 5.4 seconds (predecessor: 6.3 seconds). Despite a 26 percent higher output, the NEDC fuel consumption (combined) remained with 11.7 to 11.9 litres per 100 km at the same level as the previous model.
The two six-cylinder engines were also new. Under the bonnet of the S 350, the powerful 200 kW (272 hp) V6 engine with an 11 percent higher output used 1 litre of fuel less per 100 km, proving that fuel economies could be achieved with more powerful engines. NEDC combined consumption was 10.1 to 10.3 litres per 100 km. The new S 350 accelerated from 0 to 100 km/h in 7.4 seconds, making it 0.3 seconds faster than its predecessor.
From the first quarter of 2006, the range of engines was supplemented with a new 173 kW (235 hp) six-cylinder diesel engine. It replaced the previous six-cylinder engine in the S 320 CDI and outclassed its performance by 15 percent. The maximum torque increased by 40 Nm to 540 Nm, guaranteeing exceptional elasticity from 1600 rpm. The modern diesel direct-injection engine consumed 8.3 to 8.5 litres of fuel per 100 km (NEDC combined) and was outfitted with a maintenance-free particulate filter.
The new top-of-the-range S-Class model also went on sale in the first quarter of 2006. Thanks to its enhanced 380 kW (517 hp) twin-turbo engine, the twelve-cylinder S 600 saloon produced 12 kW (17 hp) more than before. The maximum torque increased from 800 Nm to 830 Nm and fuel consumption decreased by 0.5 litres to 14.3 litres per 100 km. The V12 engine accelerated the S-Class from 0 to 100 km/h in 4.6 seconds.
In December 2006, the range of engines was extended with another diesel version, the S 420 CDI. The new eight-cylinder model was powered by a state-of-the-art V8 CDI engine with an output of 235 kW (320 hp) and a torque of 730 Nm. With a fuel consumption ranging from only 9.4 to 9.6 litres diesel per 100 km (NEDC total consumption), the S 420 CDI stayed below the magical 10 litre mark. The tank's 90-litre volume enabled the vehicle to travel up to 1000 km on one filling.
One of the most fuel-efficient and therefore economical luxury saloons in the world, the new S 320 CDI BlueEFFICIENCY, was introduced at the end of 2008. With a fuel consumption of 7.6 litres (0.7 l less) and CO2 emissions of 199 g per kilometre (21 g less), the S 320 CDI BlueEFFICIENCY achieved the best results in its segment. Targeted fine tuning and innovative technology reduced fuel consumption and CO₂ emissions in the new models by some 10 percent compared with their already very economical predecessor. The first BlueEFFICIENCY model in the S-Class was outfitted with on-demand power steering, automatic transmission with standstill decoupling, and low rolling resistance tyres. Comfort, performance and driving pleasure remained unchanged.
Mercedes-Benz equipped the V6 and V8 models with the 7-speed automatic transmission 7G-TRONIC. Yet another novelty was DIRECT SELECT - the electronic control of the 7G-TRONIC by gently pushing a lever on the right of the steering column.
The new Mercedes-Benz S 65 AMG was unveiled at the North American International Auto Show in Detroit on 8 January 2006. Its 6-litre V12 twin-turbo AMG engine produced a driving performance that some sports car drivers could only dream of: It took the vehicle 4.4 seconds to accelerate from 0 to 100 km/h and just 13.3 seconds to reach a speed of 200 km. The maximum speed was 250 km/h (electronically limited). These unique drive dynamics were achieved by the V12 engine with a displacement of 5980 cc that had been developed by AMG and showed exceptional figures: The maximum output of 450 kW (612 hp) was constantly available between 4750 and 5100 rpm, while the maximum torque of 1000 Nm was generated between 2000 and 4000 rpm. The engine generated a torque of 570 Nm on the crankshaft already at 1000 rpm, and of 750 Nm at 1500 rpm. The transmission was handled by the AMG SPEEDSHIFT 5-speed automatic transmission with paddles and Direct-Select gear changing. The conventional automatic selector lever in the centre console was replaced with a selector lever in the steering column that the driver gently pushed to shift into ‘ P', ‘N', ‘R' or ‘D'. Flared wheel arches and a specially designed front apron with larger air intakes gave the S 65 AMG a vigorous touch. The two slanted struts and integrated round fog lights set in chrome rings made the S-Class look even wider and lower. The side skirts continued the line from the front apron and emphasized the vehicle's dynamic note when viewed from the side. It also had V12 twin-turbo lettering on the front wings.
In September 2006, the S-Class featured the full-time all-wheel drive, 4MATIC. This brand new, in-house developed drive system combined flawless traction, unsurpassed ride comfort and distinctive driving dynamics with excellent fuel economies. Two powerful eight-cylinder models were available: the S 500 4MATIC and the S 450 4MATIC. The S 320 CDI 4MATIC was the first all-wheel S-Class vehicle with a fuel-efficient V6 diesel engine. The new drive system had a centre differential with planetary gearing. The constant, fixed power distribution of 45 percent to the front axle and 55 percent to the rear axle gave the vehicle superior and predictable handling on all road surfaces. An integrated multi-disc clutch guaranteed additional traction and optimal stability as soon as the wheels started slipping. Together with the electronic driving safety systems ESP®, ASR and 4ETS, the 4MATIC models always provided for a dynamic, comfortable and safe ride, even on the worst roads. The 4MATIC logo on the boot lid and the wooden trim on the centre console were the hallmarks of the new four-wheel drives.
Mercedes-Benz added the S 600 Guard, an armoured special protection vehicle, to the high-end range of S-Class models in the autumn of 2006. Thanks to the protection components that were incorporated in the S-Guard at the factory, the vehicle offered unrivalled protection against violent assaults and threats. The special armour warded off military-grade rifle projectiles, and corresponded to the European ballistic resistance class B6/B7. In addition to meeting the conditions for assaults with hand grenades, the S 600 Guard successfully passed tests for additional conditions that weren't subject to standards. The chassis was entirely redesigned to accommodate the additional weight of the protective elements. The armoured model was exclusively available as S 600 Guard with twelve-cylinder engine and long wheelbase. Two years later, the S 420 CDI Guard was also available as an armoured diesel-powered saloon.
January 2007 saw the introduction of the armoured Pullman saloon, which was a longer version of the S 600 with a long wheelbase. This luxury limousine provided ample space for government officials and other high-ranking occupants as well as a lavishly furnished interior that included a fully equipped mobile office. The oldest automobile manufacturer in the world thus continued its long-standing tradition of incorporating high-protection components in luxury vehicles at the factory. The first saloons were delivered at the end of 2008.
The S-Class 221 was extensively redesigned in the spring of 2009. Its many innovations enabled it to maintain its position as role model and trendsetter in automotive engineering.