"Auto 2000" research car - Towards an economical, low-emission future.
V8 petrol engine with cylinder shut-off and bi-turbo diesel engine.
Pointing the way forwards for aerodynamics.
Despite its complicated wording, the project title nevertheless succeeded in firing the imagination: "Demonstration of automotive engineering research results in the form of integrated overall concepts for passenger car test models." This was how the Federal Ministry for Research and Technology worded the call it made to German car manufacturers in 1980 to devise proposals for the passenger cars of the future. The primary objective was a reduction in fuel consumption: the target limit was 9.5 litres per 100 kilometres for cars with a kerb weight of between 1250 and 1700 kilograms and 11 litres per 100 kilometres for kerb weights up to 2150 kilograms.
The cars also had to be able to accommodate at least four persons and carry a payload of over 400 kilograms, all without comprising in any way on performance, comfort or range. Clear improvements were also expected in terms of service life, ease of repair, safety and environmental compatibility compared to series-production cars of that time.
Manufacturers had until spring 1981 to prepare road-worthy prototypes of their visions for the future, which would then be unveiled to the public in September of the same year. The Federal Ministry for Research funded this ambitious project to the tune of around 110 million Deutschmarks, a figure which was then matched by the German automotive industry.
Economy, preservation of resources, reduction of emissions – all challenges to mainly test the skills of drive system researchers. Mercedes-Benz soon had two new engine concepts ready to try out in the new "Auto 2000" research car.
Despite being built around quite different technologies, the two powerplants still had one thing in common: their rated output of 110 kW/150 hp, which was deemed to be adequate at the time in view of the lightweight, streamlined body with its Cd value of just 0.28.
The petrol engine designed for the research car was derived from a standard V8 powerplant with a displacement of 3.8 liters. What made the modified engine so special was its fuel consumption, which was significantly lower at partial throttle. The key to achieving this was an automatic cylinder shut-off system that temporarily shut down four of the eight combustion chambers whenever the extra power was surplus to requirements. The fact is that four cylinders operating at full load consume less fuel than twice as many cylinders operating at partial load, resulting in the fuel consumption figure for the Euromix driving cycle (urban, 90 km/h and 120 km/h) being reduced to just 9.3 liters per 100 kilometers.
‘Safety first’ seemed to be the theme at the Frankfurt Motor Show of 1981. But as well as the occupant protection issue, Mercedes was also already addressing environmental concerns: the Auto 2000 was a pioneering concept with frugality high up on the agenda.
The Frankfurt Motor Show always offers up some surprises. In 1981 this was no different, and in addition to the production car debuts such as the W126 S-Class coupé and Porsche 944, several design studies also captured visitor interest. Mercedes surprised in the climate of unbridled performance with three versions of its Auto 2000 concept car. It sounded like the future – after all, the year 2000 was still 19 years away – and in retrospect, it even gave styling cues to the W140 S-Class which went on sale a decade later.
Aerodynamics lessons learnt in Stuttgart several years earlier during the development of the W126 flagship were built upon, resulting in the Auto 2000 concealing its windshield wipers and washers behind the A-pillars. Also, the sloping tail was more than a styling feature: the ‘Kamm-tail’ is a drag-reduction feature which can be found today on most current hybrids.
The interesting transformation of the once-conservative estate car had only one goal: to use aerodynamics and mechanical ingenuity to create a car as parsimonious with fuel as possible. Mercedes dug deep within its design department to produce three prototype vehicles each with a different propulsion method and innovative design features. The first was a petrol-engined V8 with an inventive cylinder shutdown system: four of the engine’s cylinders were idled to conserve fuel under partial engine load, a technology which is only making its way into mainstream Mercedes models three decades later.
The second car had a 3.3-litre six-cylinder diesel engine with twin turbochargers, and managed an impressive average of 31.3mpg at 75mph. However, it was the third version that was the most pioneering: a gas-turbine engine which brought several benefits, including low-pollutant combustion, low weight, compact dimensions, favourable torque characteristics, and the elimination of water cooling. The concept was still considered novel when it was used in the Jaguar C-X75 of 2010 – a testament to how forward-thinking the early-1980s Mercedes engineering department was.
While it might not have been a styling icon, the Auto 2000 concept had a raft of technological and design features that have made their way into Mercedes cars decades later. And given that gas turbine technology is yet to be used in a full-scale production car, perhaps its influence will continue decades into the future.
Source: DaimlerChrysler; www.classicdriver.com