There are a lot of ways to convert an older, dirtier car to something that uses less fuel. Most often, if you're going to start with an old diesel Mercedes, you want to add an SVO system. If you work at Mercedes-Benz, though, a recent experiment was to convert a diesel engine to, well, another diesel engine. The old diesel in question here was a 190 D from 1990. The new diesel powerplant comes from an up-to-date C-Class BlueEFFICIENCY model (above, left). The results, power output was tripled while fuel economy was improved from 32 mpg (U.S) in the original to 48 mpg (U.S.) in the converted vehicle (using the NEDC method in effect when the 190 D was made). Another easy-to-understand improvement: the original 190 D made the 0-62 mph run in a leisurely 18.1 seconds. The converted vehicle can get to that speed in 6.2 seconds.
The Mercedes 190 D BlueEFFICIENCY experimental vehicle
Back to the future: Baby-Benz with an up-to-date C-Class diesel engine
- Driving enjoyment: almost three times the output of a 190 D
- Economy: considerably more frugal fuel consumption
- Protection: many more safety and comfort features today
- What if? Practical implementation of a theoretical discussion
The idea for this unusual experimental vehicle came about during an evening discussion about the enormous developments in diesel technology over the last 20 years. The question was: "How might one make this progress directly tangible, in isolation from the equally profound changes in the safety and comfort of the car as a whole?" The result was a factory-tuned car of a different kind: the 190 D BlueEFFICIENCY. It accelerates from 0 to 100 km/h in 6.2 seconds. It therefore manages this standard sprint 11.9 seconds faster than a 190 D of the time, which caused a sensation on its 1983 introduction with its newly developed, fully encapsulated "whisper-diesel".
The differences between the two diesel generations are even more impressive when it comes to fuel consumption: despite the significant increase in output by 72 hp (OM 601, 1988) to 204 hp (OM 651, 2009), the new engine in the old body consumes 4.9 litres per 100 kilometres (NEDC) instead of the 7.3 litre figure for 1988.
But what is really astonishing is that measured according to the DIN standard used during the time of the 190 D, the Euro-Mix consumption of the current C 250 CDI BlueEFFICIENCY is a mere 4.6 litres per 100 kilometres, and 5.1 litres per 100 kilometres according to the present NEDC method. This represents an improvement of around 30 percent – not to mention the exhaust emission levels.
The playing field is by no means level: a Mercedes 190 D is 385 kilograms lighter than a current C 250 CDI BlueEFFICIENCY, for example. In addition to more interior space – the current C-Class model is 16 centimetres longer, and around nine centimetres wider and higher than a 190 – this is due to the high standard of comfort and safety features.
As a genuine Mercedes, the model 190 was ahead of its time in terms of safety technology. Nonetheless, customers at the time enjoyed nothing like the extensive array of passive and active safety systems to be found as standard in the current C 250 CDI BlueEFFICIENCY. These include seven airbags, the adaptive AGILITY CONTROL suspension and numerous assistance systems such as ESP® and ADAPTIVE BRAKE. Comfort-enhancing features like the ergonomically exemplary, multi-adjustable seats or electrically adjustable and heated exterior mirrors also contribute to the higher weight.
A number of factors are responsible for the outstanding efficiency of the current C-Class. Aerodynamics is one of them: with a Cd figure of 0.34 the 190 set an example for its time. The new C-Class betters this figure by far, however, and is once again the trendsetter in this segment with a Cd figure of 0.27. The progress is equally impressive where the powertrain is concerned: while the 190 D was equipped with a four- or optionally five speed manual transmission, the C 250 CDI has six gears available. Plus a large number of friction-reducing measures. The radiator fan, power steering and generator also operate much more efficiently than 20 years ago.