Mercedes-Benz S-Class, W 220 series (1998 to 2005)
At the Paris Motor Show in September 1998, the public was introduced to six S-Class saloons in the W 220 series, which succeeded the W 140 series after seven and a half years. It was almost delicate by direct comparison, for somehow the designers succeeded in accommodating the same feeling of space and presence within a much more slender body. But unchanged was the same aspiration to set the trend for automotive design as a whole. On its debut the new S-Class displayed over 30 technical innovations, including the DISTRONIC autonomous intelligent cruise control, navigation system with integrated congestion warning and automatic cylinder shut-off in the V8 engine of the S 500. And later came the pioneering safety system PRE-SAFE®.
When the W 220 was presented in 1998, Dr. Dieter Zetsche, then Board Member at Daimler-Benz AG with responsibility for Sales, made the comment: “In total, the new S-Class derives its desirability from the classic virtues of a Mercedes-Benz – by associating reason and emotion. Thanks to its familiar strengths of comfort and safety it guarantees a sense of calm, and with its elegant design and well-balanced driving characteristics it embodies sheer enjoyment.”
When the W 220 series was launched, there were initially two body and three engine variants. The customers were given a choice between the saloon with a short wheelbase (2965 millimetres) and the model with a wheelbase 120 millimetres longer (3085 millimetres). For each body there were three engines available. The S 320 had a 3.2 litre V6 engine (165 kW/224 hp); the S 430 a V8 engine which delivered 205 kW (279 hp); and the V8 in the top-of-the-range S 500 provided 225 kW (306 hp). All three units offered optimum combustion thanks to their three-valve technology and dual ignition. Dual ignition also made it possible to increase the volume of exhaust gas fed back into the engine, with a consequent beneficial impact on emissions.
Automatic cylinder shut-off
The newly developed automatic cylinder shut-off turned the eight-cylinder S 500 temporarily into a four-cylinder – a feature which had a dramatic impact on fuel consumption without compromising on smoothness, torque or quietness. To put that into figures, when four of the eight cylinders were shut off under partial load conditions, NEDC fuel consumption (New European Driving Cycle) for the S 500 was cut by an average of seven percent. Indeed, thanks to the automatic cylinder shut-off even greater economies were to be achieved depending on driving circumstances: At a constant 120 km/h (75 mph) gasoline consumption fell by about 13 percent, and at a constant 90 km/h (56 mph) by as much as 15 percent. The automatic cylinder shut-off was activated whenever the V8 engine was obliged to deliver only a fraction of its output and torque – for example, in city traffic, on trunk roads or for steady motorway driving at moderate speed.
At the Geneva Motor Show in 1999, a new family member, the CL coupe, celebrated its world premiere. It featured for the first time as standard the innovative suspension system Active Body Control ABC, which represented a hitherto unachieved optimum balance of sportiness and comfort. A system based on signals from sensors and using special hydraulic cylinders on the axles, ABC compensated almost entirely for any rolling and pitching motion of the body when moving off, cornering or braking. Two engines were available: The CL 600 had the twelve-cylinder unit with 270 kW (367 hp), and the CL 500 the 225 kW (306 hp) V8 engine.
The IAA Frankfurt Motor Show in 1999 presented the twelve-cylinder saloon S 600 and the six and eight-cylinder diesel versions, the S 320 CDI and S 400 CDI. The other engines were revised.
The S 600 was only available as a long-wheelbase version. The newly developed V12 engine was the same as the unit used in the CL. It was fitted as standard with such technical innovations as automatic cylinder shut-off, phased-control dual ignition, three-valve technology and AC ignition, and delivered 270 kW (367 hp) with maximum torque of 530 Nm (391 lb-ft) at 4100/min. That took the S 600 from 0 to 100 km/h (62 mph) in 6.3 seconds and gave it an electronically limited top speed of 250 km/h (155 mph).
The S 320 CDI was powered by an advanced six-cylinder unit with direct diesel injection, VNT turbocharger (Variable Nozzle Turbine) and four-valve technology. It generated 145 kW (197 hp) and at 1800/min developed maximum torque of 470 Nm (347 lb-ft). In the new European driving cycle the six-cylinder saloon used just 8.0 l/100 km (29.40 mpg/US, 12.50 km/l), giving it a range of almost 1,100 kilometres with a full tank (88 litres/23 US gal).
A bi-turbo diesel
The V8 engine with bi-turbo system in the S 400 CDI marked a further milestone in the long history of Mercedes-Benz compression-ignition engines. From a displacement of 3,996 cubic centimetres the CDI eight-cylinder unit developed 175 kW (238 hp) of output at 4000/min. Maximum torque – an impressive 560 Nm (413 lb-ft) – was available much earlier, at between 1800 and 2600/min. As for fuel consumption, the advanced diesel injection engine here proved far superior to comparable gasoline engines, with a value of just 9.0 l/100 km (26.13 mpg/US, 11.11 km/l) (NEDC combined consumption).
All W 220-series engine variants were equipped as standard with five-speed automatic transmission that also featured two driving modes, slip-controlled torque converter lock-up and an advanced lightweight design. This meant that even the transmission made a major contribution to fuel economy. Daimler-Benz had taken operation of the five-speed automatic system to a new stage of development with its so-called ‘touch shift’ function: While it was still possible to select the positions “P”, “R”, “N” and “D” as usual, in position “D” the driver could engage driving stages 4 through 1 by gently pushing the shift lever to the right or left. The manual gear selection was monitored by the transmission electronics, which only carried out shift commands that lay in the permitted engine speed range. A display in the instrument cluster kept the driver informed of the current shift position.
The W 220 series made advances in all areas of automotive design. As such, the W 220 series weighed over 300 kilograms (661 lbs) less than its predecessors with the same equipment options – one of the most important conditions for reducing fuel consumption and increasing agility. Thanks to lightweight design, exemplary aerodynamic efficiency (drag coefficient Cd = 0.27) and advanced V6 and V8 engines, the W 220-series vehicles saved somewhere between 12 and 17 percent on fuel, depending on the specific engine, over predecessor models.
In spite of having a lighter body the designers also managed to further optimize protection for vehicle occupants. Window airbags came as standard and stretched from A-pillar to C-pillar, sidebags were fitted to all doors and great attention was paid in the area of body design to reduce the risk of injury in the event of a side impact. Other standard safety innovations included belt force limiters for front seats and outer seats in the rear, front passenger airbag with two-stage gas generator and an automatic front passenger/child seat recognition system.