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The automotive industry permanently enhances Downsizing concepts due to environmental commitments and energy consumption concerns. Even in the category of city- and supermini-cars, great efforts are made for the development of highly charged engines with small displacement. So far the main focus of these developments is set on the reduction of CO2 emissions and fuel consumption. However these are not the only aspects, which have to be fulfilled by the vehicle in order to meet the demands of the customers and to be successful in competition. The NVH characteristics of such Downsizing vehicles have to match a class-specific level, which can only be achieved by additional measures. Regarding this, a view of the dynamic behavior of the entire vehicle is required. At the Institut für Kraftfahrwesen Aachen (ika) the potential for reducing fuel consumption and CO2 emissions of a Downsizing concept is investigated using a city-car as reference.

This paper presents an introduction to the requirements for shock absorbers in e-vehicles by means of a comparative study of two pure-electric vehicles from different OEM's tested in real road conditions. In this investigation the focus was on the shock absorbers, the most critical suspension components with regards to ride comfort. Different damper designs were used to investigate both in the vehicle and on the test bench. The results of the analysis in the time and frequency domains are presented.

Environmental pollution is likewise characterized by noise emissions. As a result, according to the European ambient noise directive 2002/49/EG, noise pollution of inner-city areas, in particular congested urban areas, is a major issue of the future European policy. In areas of bus stops and roofed installations, such as bus stations, there are high values of disturbing noise emissions induced by urban bus traffic. Concerning this matter, hybrid urban buses are able to offer promising solutions for an effective noise emissions reduction. At the Institut für Kraftfahrzeuge (ika), RWTH Aachen University, the project "HYBOB," financed by the BMWi (Bundesministerium für Wirtschaft und Technologie), is being conducted in cooperation with the EvoBus GmbH/Daimler Buses. The project is aiming to design and develop a highly sophisticated serial-hybrid diesel-electric propulsion system for urban bus applications.

The reduction of fuel consumption remains an important criterion in the development of new vehicles. Apart from parameters such as drag and rolling resistance, the efficiency of the drive train also plays an decisive role. Following a concentration on the engine and transmission over the past few years, attention has now turned to apparently less important components such as axle joints and how these can be incorporated into the fuel consumption reduction process. Since the transmission losses of axle joints are relatively low, “classic” methods to determine the efficiency (such as MD-measurements using wire strain gauges) are inapplicable due to the attained accuracy. A new method has thus been developed at the Institute of Automotive Engineering (ika), which enables a very accurate recording of the efficiency of joints (±0.03 percentage points).

In April 1996 the European Project „Electric Vehicle Fleet Demonstration with advanced Batteries” has been started with financial support of the European Commission. Sixteen electric vehicles equipped with ZEBRA batteries have been built up as prototypes and are now operating in five major European cities. Today, after 1½ years of fleet operation the fleet of 10 OPEL Astra Impuls has covered a mileage of more than 275.000 km and the project can be evaluated sufficiently exact to extrapolate the project results. Energy consumption structures, mobility structures (daily trip length) and user acceptance have been analyzed and will be discussed in detail.