Press Release
Comprehensive diesel expertise at Mercedes-Benz
Rudolf Diesel??????????????????????????????????????s principle of self-ignition is closely linked with the history of Mercedes-Benz. The brand has acquired more than 70 years?????????????????????????????????????? experience with the diesel engine worldwide. Milestones such as the world??????????????????????????????????????s first production diesel passenger car (1936), the delivery of the one-millionth diesel passenger car in the post-war era (1971), the first use of a diesel particulate filter in the USA (1985) and premieres of the four-valve technology (1993) and the diesel direct injection passenger car (1996) are just a few of the highlights in the diesel engine??????????????????????????????????????s success story. Since the presentation of the top-of-the-range model S400 CDI in 2000, Mercedes-Benz has offered the widest range of diesel engines in Europe ?????????????????????????????????????? from the powerful V8 to the economical three-cylinder engine for the smart. And in autumn 2003, Mercedes-Benz became the world??????????????????????????????????????s first automotive brand to offer diesel engines complying with the EU4 emissions standard in combination with diesel particulate filters. Today, Mercedes-Benz offers all 42 diesel passenger car models with a maintenance-free diesel particulate filter as standard equipment ?????????????????????????????????????? thereby setting a unique standard.
The diesel??????????????????????????????????????s popularity is due to the unmatched efficiency of its combustion process. The developments of the last 15 years ?????????????????????????????????????? for example, the electronic valve timing, four valve technology, common-rail-direct injection and turbochargers with variable geometry ?????????????????????????????????????? have enabled the Mercedes developers to build on its good consumption characteristics, and so to extend its lead over the spark ignition engine. What??????????????????????????????????????s more, thanks to the engine??????????????????????????????????????s excellent torque characteristics, these have been joined by convincing driving pleasure and comfort ?????????????????????????????????????? properties that put the diesel on a level with the petrol engine, and sometimes even a cut above.
Fifty-seven per cent of all Mercedes customers in Western Europe alone decide to purchase a fuel-efficient diesel car. In the USA, diesel passenger cars have fallen back after their great successes in the 1980s. However, there are now positive signs of a change in the perception of this drive system, which has undergone enormous development both economically and technologically. The factors behind this change are the currently extremely high crude oil prices and the concern over national security of supply. Thanks to this political background and the US traffic conditions, with vast overland stretches ideally suited to the diesel, the engine continues to hold great potential in the USA.
Three E 320 CDI production vehicles impressively demonstrated that the V6-CDI is not just a proverbially economical and reliable engine at record drives in Laredo, Texas, last spring. They also showed their stamina and their sportiness by setting a number of world records at an average speed of 224.823 km/h over 100,000 miles.
The vehicles participating in the world record drives were also equipped with the current state of the art in exhaust purification technology. Thanks to the use of a maintenance-free diesel particulate filter, the particulate emissions typical of diesels were cut by more than 90 per cent ?????????????????????????????????????? better than the EU 4 exhaust gas limits require. And once the tough and unusual stresses of the record drive were over, the T?????????????????????V (Technical Inspectorate) was able to confirm that the strict legal limits were still being maintained.
Fuel still holds great potential
Every efficient and environmentally friendly drive concept is a partnership of two elements ?????????????????????????????????????? the engine itself and the fuel. Only when the fuel is burnt as completely as possible, with the minimum of residues, can the drive system operate with the lowest emissions. That means that every fuel ?????????????????????????????????????? for petrol and diesel engines ?????????????????????????????????????? should be matched to the respective combustion concept.
Sulphur, a natural component of petroleum, is a decisive player in this context, as it has a substantial effect on the emissions. On the one hand, sulphur and its products, the sulphates, have a negative effect on the particulate emissions. On the other, sulphur damages NOx traps. That??????????????????????????????????????s why Mercedes-Benz is backing BLUETEC ?????????????????????????????????????? which is more tolerant of sulphur ?????????????????????????????????????? for reducing oxides of nitrogen in diesel exhausts. Nonetheless, the worldwide use of fuels with a maximum sulphur content of 10 ppm ?????????????????????????????????????? that corresponds to a concentration of ten parts of sulphur to one million parts of fuel ?????????????????????????????????????? is to be desired.
This low sulphur concentration is already standard in large parts of Western Europe. However, this is still a long way from being the case in other parts of the world. In the USA, for example, diesel grades with sulphur contents of 350 ppm and more are still normal. Plans, however, call for sulphur levels to be cut to 15 ppm in the USA by 2006. Mercedes-Benz is therefore actively supporting the introduction of cleaner fuels as a part of its efforts to offer customers vehicles with the most modern technology possible and so with the lowest possible emissions. Consumption and emissions can only be further optimised by means of the combination with optimised fuels ?????????????????????????????????????? for diesel and petrol engines. And what??????????????????????????????????????s more, this step would immediately have a significant positive effect on the pollutant emissions of older engines too ?????????????????????????????????????? over the entire vehicle fleet. Mercedes-Benz therefore views efforts to reduce the sulphur content of fuels worldwide as an urgently needed improvement in fuel quality, although it is not the only improvement necessary.
The natural gas alternative: Good for the environment and the wallet
A logical option for an environmentally friendly drive system, in that it??????????????????????????????????????s already available, is a switch to natural gas. Mercedes customers have had this option since the spring of 2004, with the E 200 NGT (Natural Gas Technology). The E 200 NGT, the top-performing natural gas-powered saloon on the market, can run on either natural gas or unleaded premium petrol. Switching between the two drives is also possible while the car is being driven, and the transition isn??????????????????????????????????????t even noticed by the driver. The engine is based on the E 200 Kompressor, and it is tuned so that power (120kW/163 hp) and maximum torque (240 Nm) are the same with either fuel. The fact that the 18 kilograms of natural gas are transported in a gas cylinder, in addition to the petrol tank, results in the vehicle having a range in excess of 1,000 kilometres.
The natural gas drive has economic and environmental benefits. Depending on its origin, natural gas consists of far more than 90 per cent methane (CH4). Methane??????????????????????????????????????s purity and high hydrogen content mean that its combustion produces less pollutants than burning conventional liquid fuels. And as a result of its low carbon content, the CO2 emissions are 20 per cent lower. And the operating costs are lower by half, a very welcome added benefit for the customer. Based on the current price of natural gas, about 0.72 euros per kilogram, that corresponds to a per-litre price of 0.48 euros, when calculated as the energy equivalent of petrol. This shows that natural gas is not only an environmentally friendly alternative but also an economical choice: With the definition of the minimum tax rates valid until the year 2020, customers can enjoy the security of long-term planning.
Gas To Liquid: Fuel from natural gas
Another viable transition to a fuel of the future could be a liquid fuel synthesized from natural gas, which otherwise wouldn??????????????????????????????????????t be economical to use. This conversion produces what??????????????????????????????????????s known as a ???????????????????????????????????gas-to-liquid???????????????????????????????? (GTL) fuel. This indirect application of natural gas after it has been liquefied would have a decisive advantage: A dedicated network of filling stations would not be necessary. In contrast to the direct use of natural gas, which must be stored in pressurised tanks, GTL can be handled at the filling station like conventional diesel fuel and offers further benefits in terms of emissions. It has already been demonstrated that it will be possible to economically produce such a fuel in the future. In view of rising crude oil prices, this represents an economically feasible and environmentally friendly alternative. Such ???????????????????????????????????designer fuels???????????????????????????????? are free from sulphur and aromatics and can, within certain limits, be ???????????????????????????????????customised???????????????????????????????? for future combustion processes.
