BMW ActiveE Concept

The BMW Group presents yet another milestone along the way to achieving CO2-free mobility. The BMW Concept ActiveE provides a taste of a purely electrically powered BMW. Focused on the requirements of practical use, the study is based on the BMW 1 Series Coupe and embodies the outstanding agility and characteristic driving pleasure of the 1 Series for the first time as part of an emissions-free drive concept.

With the world premiere of the BMW Concept ActiveE at the North American International Auto Show (NAIAS) 2010 in Detroit, the BMW Group is highlighting the continuation of its research and development activities in the field of electro-mobility. The field tests with the MINI E as part of project i in the US and Europe have already provided important insights into the demands required of future production electric vehicles. As a second step, project i has begun development of a second trial fleet of electric vehicles based on the BMW Concept ActiveE. These vehicles are likewise intended for everyday use by private and select fleet customers as part of a large-scale field test. The insights gathered in the process will be fed into the development of an electrically powered serial production vehicle which the BMW Group will put on the market under a sub-brand of BMW in the first half of the next decade.

The BMW Concept ActiveE has allowed BMW to explore new vehicle packaging solutions and components which will be crucial to the success of the Megacity Vehicle. The intelligent integration of drive components within the existing vehicle package of the BMW 1 Series Coupe offers the opportunity to provide four full-size seats and a luggage compartment with a capacity of some 200 litres / 7 cu ft. The motor, specially developed for the model and located in the rear axle, delivers 125 kW/170 bhp and provides maximum torque of 250 Nm / 184 lb-ft. It accelerates the vehicle in less than 9 seconds from zero to 100 km/h (0-60 mph in approx. 8.5 seconds).

The electric drive system draws its energy from new, advanced lithium-ion battery pack optimize developed jointly by BMW and the co-operation partner SB LiMotive especially for the BMW Concept ActiveE. They enable a range of approx. 160 kilometres (100 miles) in everyday use. An intelligent battery management system helps achieve this range largely independently of external climatic conditions. Additionally, the charging period required for the lithium-ion batteries is very short. On the European power grid, the battery pack can be fully charged in just 3 hours at a wall box with a current of 50 ampere at 230/240 volts. In North America, using a high- current (32 ampere continuous) residential wall box, the charge time is about 4.5 hours.

he BMW Concept ActiveE offers the prospect of characteristic BMW driving pleasure without exhaust emissions. The requirements for electro-mobility with characteristic BMW properties are being created based on ongoing development in the powertrain. The latest outcome is a new synchronous electric motor tailored to the BMW Concept ActiveE. It offers a high level of efficiency, power delivery, and compact construction. The maximum output of the new electric drive is 125 kW/170 bhp. The maximum torque of 250 Nm / 184 lb-ft is available from a standstill as is typical for electric motors. The torque remains available over an unusually broad load range. Unlike asynchronous electric motors, the new power unit provides a relatively high level of torque even at higher engine speeds and road speeds; at increased load the torque is not reduced abruptly but decreases gradually. The torque curve at higher engine speeds is therefore much more similar to the pattern familiar from combustion engines.

The vehicle concept and drive system provide the agility and dynamic acceleration performance which are characteristic of the BMW 1 Series Coupé. Based on realistic simulations, a figure of less than 9 seconds was measured for the sprint from zero to 100 km/h (0-60 miles in 8.5 seconds), with the 60 km/h mark being reached after less than 4.5 seconds. The maximum speed of the vehicle is electronically limited at around 145 km/h or 90 mph.

The innovative character of the electric drive is also reflected in the optimized ratio between engine output and space requirements: the compact power package is fully integrated in the rear axle of the BMW Concept ActiveE. Here the drive system occupies the space required in conventional vehicles by the differential, whose function is integrated in the drive system.

Another special feature of the battery pack is its outstanding compactness, despite its output and capacity. The arrangement of battery cells, grouped into several modules, is ideal in terms of packaging, functionality and vehicle balance. The battery pack is located where a combustion engine and fuel tank would normally be located. The largest portion of the battery pack in the BMW Concept ActiveE is located where the conventional propshaft and fuel tank would be in the lower section of the vehicle. In addition, a portion of the battery pack is located where the combustion engine would normally reside. Using intelligent lightweight design and the highly-efficient lithium-ion battery cells, vehicle curb weight is limited to about 1800 kg / 3900 lbs.

Source: BMW press

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