With more than 500,000 units produced within three and a half years, the A-Class is among the bestsellers in the Mercedes-Benz passenger car range. Now the latest generation of this compact car is showing itself to be more youthful, attractive and environmentally compatible than ever before.
2009 Mercedes-Benz A-Class2009 Mercedes-Benz A-Class features a completely revised design, high-grade appointments and new technical developments which further improve safety, comfort and economy. A convenient ECO start-stop function which reduces urban petrol consumption of these BlueEFFICIENCY vehicles by up to nine percent is now available for the high-volume models A 150 and A 170, for example. For the three-door A 160 CDI Mercedes-Benz has developed an additional BlueEFFICIENCY package which lowers the fuel consumption of the Coupé by more than eight percent. Independent experts have acknowledged these great advances in the environmental field with an internationally valid environmental certificate, which the A-Class is the world’s first compact car to achieve.
The new-generation A-Class with the 160 CDI BlueEFFICIENCY system will average 52mpg and should be a model of fuel economy. Thanks to detailed improvements, the fuel consumption of the state-of-the-art direct-injection diesel engines has been reduced by more than eight percent or 0.5 litres per 100 kilometres compared to the preceding series. From autumn 2008 Mercedes-Benz will introduce a standard BlueEFFICIENCY package for the three-door A 160 CDI with a manual transmission, with further improvements in engine efficiency, aerodynamics, rolling resistance, energy management and weight. The sum of these measures achieves a fuel saving of 0.4 litres, which means that the A 160 CDI BlueEFFICIENCY has an NEDC consumption of just 4.5 litres per 100 kilometres. As a result the CO2 emissions of the 60 kW/82 hp Coupé are 119 grams per kilometre.
The BlueEFFICIENCY package also includes an aerodynamically optimised radiator grille. This has a closed-off interior face to reduce the airflow to the engine, though the CDI engine is still cooled effectively at all times. The suspension has also been lowered by ten millimetres to reduce the drag coefficient even further.
Mercedes engineers have exploited an additional fuel-saving potential by controlling the onboard power supply of the A 160 CDIBlueEFFICIENCY according to demand, and therefore on an energy-saving basis. A sensor constantly monitors the battery so that the output of the generator can be reduced for certain periods when the battery is well charged. This reduces the work required of the engine, which therefore consumes less fuel. To recharge the battery with optimum energy efficiency, the generator management system utilises the engine’s overrun phases to produce electrical energy.
Start-stop function: the engine switches off automatically when idling
In the case of the petrol engines, Mercedes engineers have achieved NEDC fuel savings of up to 0.4 litres per 100 kilometres with a newly developed ECO start-stop function. From autumn 2008 this system will be available for the high-volume models A 150 and A 170 on request. It automatically switches off the engine when the driver shifts the manual transmission to neutral at a low speed while applying the brakes. If the conditions for engine switch-off are met, the driver is informed by a special display in the instrument cluster.
Within fractions of a second, and almost noiselessly, the engine is restarted as soon as the clutch is operated or the brake released. This rapid and comfortable engine start is a major advantage of the ECO start-stop function versus other systems of this kind. To this end Mercedes-Benz uses a starter generator which is linked to the crankshaft via the drive belt. As a result the engine starts much more rapidly and quietly than with the conventional starter. During a journey the starter generator feeds electrical power to the onboard network of the A-Class.
Economy: nine percent lower fuel consumption in city traffic
With the ECO start-stop function the NEDC fuel consumption is reduced by a further 6.5 percent or so. The A 150 BlueEFFICIENCY (70 kW/95 hp) absolves a measured test journey with a fuel consumption of 5.8 litres per 100 kilometres, which corresponds to 139 grams of carbon dioxide per kilometre.
Even greater advantages can be achieved in normal road traffic, as the results of extensive practical trials have confirmed: Mercedes employees tested the system in 175 test cars, covering a total of around 1.2 million kilometres. Roughly half of this enormous mileage was covered in city traffic, where the new ECO start-stop function enabled fuel savings of up to nine percent to be achieved.
Ecology: the A-Class is the first compact car with an environmental certificate
Practical trials such as this are of immense importance to Mercedes-Benz when it comes to evaluating new technologies. The environmental compatibility of vehicles is not only assessed on the basis of standardised emissions and fuel consumption measurement, but also taking into account the entire vehicle lifecycle – from production and many years of operation to eventual recycling and disposal. An analysis of more than 40,000 individual processes provides an overall picture and enables the development work to be objectively assessed.
This form of environmental audit is the basis of the environmental certificate according to the stringent international ISO standard 14062 (Design For Environment), which Mercedes-Benz is the world’s only automobile brand to have received. This certificate also applies to the new-generation A-Class, confirming the considerable advances made in the field of environmental protection. An analysis over a vehicle mileage of 150,000 kilometres shows that CO2 emissions are around seven percent below the figure for the preceding model (W168) of 2004, for example. Nitrogen oxide emissions have been reduced by no less than 13 percent.
Even better results are achieved by the A 150 BlueEFFICIENCY with the ECO start-stop function. Thanks to this new technology, carbon dioxide emissions over the entire lifecycle are reduced by a further five percent, which means that the environmental audit shows a remarkable reduction in CO2 emissions by more than twelve percent compared to the preceding model.
Aspects other than favourable fuel consumption and low exhaust emissions are also important for the environmental certificate. For example the recycling concept of a vehicle: the A-Class already meets the EU regulation coming into force from 2015, which prescribes a recycling rate of 95 percent. Plastic components with a total weight of 30.8 kilograms can be produced from high-grade recyclates – twice the figure achieved for the preceding model.
The A-Class also demonstrates its environmentally compatible concept by the use of renewable raw materials. Mercedes-Benz has various components of the compact car produced with the use of flax, olive stones, cotton, coconut fibre, wood veneers and abaca fibres. The weight of these components has increased by one third versus the preceding model. Detailed information about environmental audits may be found in a Mercedes-Benz brochure, which is available on the internet at www.media.daimler.com .
