The first generation of the A-Class (W 168 series)
- More than 1.1 million cars from 1997 to 2004
- The small Mercedes-Benz established itself firmly in the market
- Long and short wheelbase as well as many engine variants
The two A 140 and A 160 models with gasoline engines were the first variants of the A-Class to be launched onto the market in October 1997. The A 140 had an engine with 1397 cubic centimeter displacement, with which it developed 82 hp (60 kW), while the A 160 with 1598 cubic centimeter displacement generated 102 hp (75 kW). The top speeds were 170 km/h and 182 km/h, respectively.
Within the model range more than 20 technical innovations were incorporated which were previously not available in this car category. The unique sandwich concept for the bodywork had been fully developed and implemented: engine, transmission and axles were housed in front of and below the passenger compartment. This had many advantages. In the event of a head-on crash the drive system unit dived underneath the passenger compartment of the A-Class. The model achieved the safety levels of larger Mercedes-Benz sedans with a vehicle length of only 3.57 meters (50 centimeters shorter than comparable competitors) and with a weight of only 1000 kilograms.
Thanks to the sandwich principle the A-Class also attained the levels of spaciousness of a medium-size sedan. The innovative rear seat assembly and optionally removable front passenger seat provided the variability of a mini-van. In total 72 different seat variations were possible, and in terms of load volume the A-Class achieved the level of large station wagons: between 390 and 1340 liters depending on the position of the rear seat, or even 1740 liters with the front passenger seat removed. The flat floor, the large tailback and the low loading edge facilitated loading of the luggage compartment.
The stable floor assembly made up of a network of straight longitudinal and cross members was an integral element of the innovative safety concept. At the front end of the longitudinal members there was a novel front module made of aluminum with two lateral crash boxes. These were bolted to the longitudinal members and could be replaced quickly and relatively cheaply after an accident. For the first time in Mercedes-Benz large-scale production, plastic was used for the front fenders which resumed their original shape again after a light collision without requiring repair or paintwork. In order to save on weight the tailback was also made of plastic. The easy-to-repair structure of the A-Class not only reduced the cost of repairs after an accident but also resulted in a low insurance classification.
In terms of passive safety the model series achieved practically the same level as the exemplary Mercedes-Benz E-Class. Besides the sandwich principle the restraint systems installed as standard and which were specially adapted to the A-Class concept with its short crumple zones contributed to this result. They included full-size airbags for driver and front passenger, inertia-reel seat belts with belt tensioners on the front and outer rear seats, as well as belt force limiters on the front seats.
The Mercedes-Benz engineers broke new ground in the development of the drive system. For the engine and transmission of the A-Class represented elementary components of the spatial and safety concept like in no other car. Not only the targeted displacement class but also the dimensions and the location of the engines ruled out the use of components from the traditional modular system but required new designs. The result was a completely new generation of four-cylinder engines with a light-alloy engine block: two gasoline engines from the M 166 series, and two turbodiesel engines from the OM 668 series. As a result of strict weight-shedding, all four engines turned out to be more than 25 percent lighter than other four-cylinder models of their displacement category. The drive system was installed immediately below the pedal floor in an oblique position. The top side of the drive unit facing the passenger compartment floor was designed as a sliding surface so that in the event of a frontal impact the engine-and-transmission assembly could slide downwards along the pedal floor.
The new ASSYST active service system which continuously analyzed the oil quality in the engine, allowed maintenance intervals for all A-Class engines according to the actual operating conditions – with intervals thus being extended to up to 40,000 kilometers. The innovative four-cylinder engines were produced at the Untertürkheim plant where passenger car engines have been manufactured since 1904.
The chassis of the A-Class was also a completely new development. The design engineers were not able to carry over existing designs, as these were not compatible with the innovative spatial concept. At the front a modified McPherson system with coil springs, twin-tube gas-filled shock absorbers and anti-roll bar was therefore used. The axle components were mounted together with the rack-and-pinion steering and the engine-transmission assembly on a frame-type integral support which was bolted to the bodywork at eight points. At the rear, a trailing-arm suspension with coil springs, single-tube gas-filled shock absorbers and anti-roll bar was used. This axle assembly could be arranged beneath the load floor without impairing interior space. The shock absorbers and springs were mounted obliquely in front of the wheel center in a space which could not be used in any other way.
The A-Class appointments followed the proven concept of different design and equipment lines. In 1997 three variants – Classic, Elegance and Avantgarde – were available. The three design and equipment lines were presented at the 57th Frankfurt International Motor Show a few weeks before the market launch.
All lines had comprehensive standard equipment in common. Compared with the basic Classic version, Elegance offered a range of additional equipment related to both the interior and the exterior: light-alloy wheels, radiator grille and exterior mirror casings painted in bodywork color, chrome inlays in the door handles and two-tone tail light covers. Avantgarde was the technically progressive model variant. It was characterized by light-alloy wheels with wide tires, a silver-painted radiator grille and exterior mirror casings painted in bodywork color, as well as monochrome tail light glass.
The model series was very well received. Public opinion was matched with accolades from the experts. In 1997 the A-Class received two coveted prizes. On November 10, Jürgen Hubbert, member of the Board of Management, accepted the “Großer Österreichischer Automobilpreis 1997″ (Grand Austrian Automobile Prize) from Austrian Chancellor Viktor Klima. Two days later the A-Class was honored in Berlin with the “Goldenes Lenkrad” (Golden Steering Wheel) awarded by the newspaper Bild am Sonntag.
Manufactured in an integrated production network
Large-scale production of the gasoline-engined A 140 and A 160 models began in Rastatt in 1997. Daimler-Benz’s third passenger car assembly plant manufactured the A-Class as part of an integrated production network with six other domestic plants: sheet steel panels were obtained from Sindelfingen, engines, transmissions, front axles and drive shafts from Untertürkheim, oil and water pumps, crankshafts and camshafts from Berlin, differentials from Kassel, steering systems from Düsseldorf and finally rear axles, jacket tubes, exhaust manifolds and lever-type parking brakes from Hamburg.
In body-in-white assembly, a complete A-Class body was produced from 290 individual sheet steel panels with 3,700 welding spots, and then painted in a globally unique process with high levels of environmental compatibility, efficiency and quality. The principal elements of this fully-automated process, which was developed in collaboration with partners BASF and Dürr Systems, were the integrated painting concept which allowed the omission of the filler layer, the powder-slurry method for the solvent-free clear coat as well as a novel corrosion protection concept which did without cavity conservation.