Testing For The Big Freeze

| Environmental Testing

The prototype BMW i5 electric vehicle was put through a one-year endurance test

BMW combines test facilities and proving grounds to put its latest electric vehicle through challenging winter tests

The first BMW 5 Series car with a fully electric drive system has yet to make its global debut, but it has already come through an extended endurance test in the harshest of conditions. During this crucial testing phase, the BMW i5 had the opportunity to demonstrate both the stability of its electric powertrain and its dynamic performance qualities over the course of arduous test drives in winter conditions.

The programme of testing on ice and snow lasted about a year in all, from the initial test runs to the final stages of fine-tuning. During the extensive testing on country roads, motorways and specially prepared test tracks, the development engineers mainly focused their attention on the car’s ability to drive at low temperatures and on surfaces offering little grip.

The innovative powertrain and chassis control systems on board the i5 need to perform a lot of tasks in order to optimise its traction, dynamism and driving stability, and nowhere is this more apparent than on a solid blanket of snow, icy mountain roads or frozen lakes. It was only right that the dynamic winter testing of the purely electrically powered car recently finished exactly where it began: in the biting cold of the BMW Group’s winter test centre at Arjeplog in northern Sweden.

Sub-zero temperature testing

As part of the production development process, the car first had to prove its mettle back in February 2022, when it completed a road trip from Munich to the BMW test centre at Arjeplog. A fully camouflaged prototype model fitted out with a special wrap, plastic attachments, grilles and provisional headlights and rear lights set off on a five-day test drive from the foothills of the Bavarian Alps up to Denmark, then on to the edge of the Arctic Circle in Swedish Lapland.

The journey of around 3,000 kilometres (1,850 miles) provided an early opportunity for the motors, power electronics, high-voltage battery and integrated heating and cooling system for the cabin and battery pack to demonstrate their advanced level of readiness on a long-distance journey. Featuring cutting-edge battery cell technology and intelligently controlled thermal management, the fifth-generation BMW eDrive technology – further upgraded for the BMW i5 – forms the basis for long ranges and short charging times during breaks in the journey, even in extreme sub-zero ambient temperatures.

The final destination of Arjeplog provided the team of development and test engineers with the ideal venue for their test programme. The snow-covered roads and frozen lakes of northern Sweden, with their vast expanses of ice, create the perfect setting for exploring how the chassis components, steering and braking systems, and driving dynamic and driving stability systems all interact with one another in extreme outdoor conditions. As a result, the groundwork for the handling of the i5 were already laid in the first test drives in Arjeplog.

This was followed by more testing over the course of 2022, both at other BMW Group test facilities and in everyday driving in and around Munich as well as in the vicinity of BMW Group Plant Dingolfing. The task here was to continue refining the car’s chassis technology and acoustic properties under a wide variety of conditions, as well as honing the drive unit’s power delivery, in order to produce a well-resolved driving experience at all times.

Here again, part of the development work was deliberately carried out during the colder months on icy and snowy roads in the Alpine foothills. Last winter, BMW i5 prototypes – now sporting less camouflage and near-production headlights – were regularly sent out for testing to verify the functionality and reliability of their powertrain and chassis control systems in extremely demanding road and weather conditions. The BMW engineers involved in the vehicle project were able to directly inspect the current state of development through testing in the BMW brand’s native Bavaria before it was time to return to endurance testing near the Arctic Circle in February 2023.

Snow and ice handling

The purpose of this second round of testing in Sweden was to fine-tune all powertrain and chassis control systems. Thanks to their low-grip surfaces, the test areas sited on frozen lakes around Arjeplog were particularly well suited for delicately adjusting the drive torque control system in the car under precisely reproducible conditions. The DSC (Dynamic Stability Control) system, the near-actuator wheel slip limitation function and the drive torque control system are interlinked so that they can interact and complement each other flexibly in any driving situation. As a result, the electric car performs at least as proficiently as any conventionally powered model on ice and snow.

The integrated application of all powertrain and chassis systems underpins the outstanding handling abilities displayed by the car in winter testing. The more challenging the conditions, the more impressive were the speed and precision of the control systems in the fully electric version of the well-established BMW 5 Series in its new electric guise. It produces a blend of optimum traction when pulling away and supreme driving stability when cornering or braking, which is unique in the competitive environment.

New Proving Ground

The BMW Group has also recently launched its new test site in Sokolov (Czech Republic) referred to as the Future Mobility Development Centre (FMDC).

As the first development location of its kind in central Europe, the FMDC, in which 300 million euros have been invested, will play a key role in the company’s future mobility development. The former mining region has transformed into an innovation hub employing more than one hundred skilled workers. The surrounding terrain offers the best real-world conditions for testing of highly and fully automated driving and parking to supplement the virtual simulation of driving situations. Through this combination of virtual simulation and real-world testing, the BMW Group meets the highest safety requirements of its customers. The FMDC in Sokolov rounds off BMW’s existing group of test sites in Aschheim near Munich, Miramas in France, and Arjeplog in Sweden.

According to Frank Weber, BMW Board Member for Development, with its Future Mobility Development Centre, BMW has created a one-of-a-kind test site, designed exclusively for the highly demanding testing of automated driving and parking up to level 4 autonomy. On 600 hectares of land, BMW is able to test all possible driving conditions with maximum flexibility and tremendous efficiency, whether that’s city, countryside, highway or even automated parking.

“The special thing is that we can run our test modules one after the other without stopping, which makes our testing as realistic, reliable, and customer-oriented as possible,” Weber says.

The test site is also claimed to be an example of how the highest environmental protection and sustainability standards have been implemented. Throughout the planning and establishment of the test track, BMW worked in close cooperation with specialized ecological construction monitoring.

BMW Real Estate board member, Ilka Horstmeier believes that making mobility electric, digital, and sustainable goes beyond just vehicles and extends to the entire value chain, including BMW’s own sites.

“Together with our partners, we were able to develop a former surface mine site here in Sokolov into a modern and efficient test site with its own charging infrastructure supplied with one hundred percent green electricity from renewable energy sources,” says Horstmeier.

Jonathan Newell
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