Miguel Sánchez
At the time this article is being written, anti-aircraft alarms have sounded again in a European capital. Russian troops advance through Ukrainian territory, returning the war to the borders of the Old Continent. bombed cities. Destroyed infrastructure. Civilians at the expense of mercenaries and enemy soldiers. Millions of refugees exposed to uprooting and trafficking networks. And furthermore, in the center of all this a nothing underground energy crisis caused by the confrontation with a nuclear power that happens to be the world's third largest oil exporter. Undoubtedly, a gloomy scenario for our productive system dependent on hydrocarbons.
However, as history tends to behave this has not happened now for the first time. Far from it, as early as 1973 there was the first serious warning about how fragile oil supplies can be when political problems are involved. On that occasion, the spark responsible for the fire was the Yom Kippur War. A military confrontation between Israel, Syria and Egypt that reminded the world of the consequences of the bloc policy. Thus, a large part of the population began to become aware of the long and tortuous path that crude oil travels from where it is extracted to the deposit of our vehicles.
In this way, the automobile industry undertook one of its most important changes of direction in terms of technological development. Suddenly, moderate consumption should not only be the keynote in modest models like the 2CV or the Beetle. They should also be present in the mid-range and high-end sedans. those in which everything was designed for the comfort provided by large displacement engines with great torque from low revs. Kind of like squaring the circle. Having to offer the consumption of the diesel engine without sacrificing the power, smoothness and performance of those powered by gasoline.
MERCEDES AND ITS PROVISIONAL CHARACTER
Despite the fact that the United States had lived in the notion of inexhaustible resources, the Oil Crisis of 1973 forced it to rethink many elements of its economic system. Thus, In 1975 the federal administration created the Corporate average fuel economy. A series of measures approved by Congress -and implemented through the Ministry of Transportation- for the progressive reduction of hydrocarbon consumption in the country. Of course, avoiding the direct regulation of prices. As well as possible subsidies for the purchase of especially efficient vehicles.
Far from it, these policies introduced sanctions to manufacturers in the case of launching models above the recommended consumption. In this way, the automobile industry experienced one of its most frenetic moments of creation during the seventies. Rethinking engine engineering as it had already done in the early twenties under the theories of Vittorio Jano and the reduction in displacement. However, how would they do it this time? How to reduce consumption without losing power? Well, although in its infancy, within motorsport there was a technology that could solve this paradox.
It was about turbocharging. Born at the beginning of the XNUMXth century in the world of aeronautics, this system was seen as the panacea when it came to increasing power without the need to create completely new engines. A most attractive way of working. Even more so if we take into account the scenario that was being created in countries like Italy. Where the state began to heavily tax models with more than two liters of displacement. Making even Ferrari use the turbo for the first time in series models to create the 208 de 1982 as an access model.
However, when it came to reducing consumption there was also another option. diesel engines. Called noisy, brusque and unhappy in their response, they seemed to be doomed not to leave the scope of the industrial mobile park equipping trucks, vans and tractors. Anyway, by the mid seventies Mercedes had already been equipping several of its sedans with diesel engines. And it is more, in 1975 they doubled the bet using the third unit of the spectacular prototype C111 as a diesel test bench. Something that silenced not a few voices. Especially when in June 1976 he managed to ride the Nardo circuit for 60 uninterrupted hours at an average speed of 252 km/h without any breakdown.
THE FIRST: MERCEDES 300SD
The feat achieved in Nardo had several effects on the automobile industry at the time. To begin with, the fact that a prototype with futuristic and ultra-sporty aesthetics carried a simple, three-liter, five-cylinder naturally aspirated diesel engine made us rethink many things about the world of racing. Secondly, that C111 gave great prestige to Mercedes just at a time when fine-tuning diesels for the world of passenger cars was a necessity almost imposed by law. And finally, thanks to everything learned in this project, Mercedes was ready to take a decisive step further in the world of diesel.
And no, it was not about coupling the engine of that C111 to a series model. At the end of the day, that would have given very brief results since a large part of the success came from careful aerodynamics, a very low weight and a set-up that was impossible to carry on a day-to-day basis. In fact, while the 111 Nardo C1976 reached up to 200CV, its same engine block delivered only 80CV in the 240D series marketed in the United States. So, what to do? How to extract the necessary power from that five-cylinder to make it worthy of equipping a mid-high-end sedan?
The answer came from the turbocharger realm. A technology that hardly anyone had thought to mix with diesel in the application to tourism models. And we focus on passenger cars, since in the distant 1925 the application of a turbocharger to a diesel engine had already increased its power by 40%. In fact, since the XNUMXs the use of turbodiesel technology was normal. Of course, always in industrial vehicles such as Saurer heavy trucks. However, Mercedes once again demonstrated why it is one of the world's most decisive brands in automotive engineering. Applying for the first time in a large series touring model the combination of turbocharging and diesel in the 300 Mercedes 1978SD. Only marketed in the United States and Canada. Included within the W116 range.
Which was also offered there with six and eight cylinder engines and displacements ranging from 2.8 to 6.9 liters. Regarding performance, even mounting the five cylinders of the 240D the Mercedes 300SD reached up to 115CV. In addition, the average consumption in a combined road and city cycle marked just over 10 liters per hundred kilometers. This way, the Mercedes 300SD was much more efficient than its competition. Especially when compared to vehicles from Detroit companies. The result of all that was sales in which 26.634 units were registered. Very noticeable for an import model such as the Mercedes 300SD. In addition, facing the history of motorsports, this has become the first in something as important as turbodiesel engines. A most interesting Mercedes.
Photographs: Daimler
