German luxury carmaker Audi is working with Tier 1 supplier MANN+HUMMEL to develop a particulate filter for electric cars that collects particulate matter from the surrounding area both while driving and charging.
The technology already has demonstrated its effectiveness to help improve air quality in cities during a first pilot phase. The innovative technology will be demonstrated at the Greentech Festival in London.
The OEM says regardless of a vehicle’s drive system, 85% of fine dust in road traffic is caused by brake, tire, or road abrasion. The smallest dust particles, hardly noticeable to the naked eye, are only a few micrometres in size with a diameter of only 10 micrometres and can therefore be easily inhaled. In the past year, the World Health Organisation (WHO) has recommended significantly lower particulate matter limits than in the past but according to experts, it would be impossible to comply with these new values in many urban areas in Germany.
The pilot project was launched in 2020 and will run for a period of four years, Fabian Groh, Project Manager in Attachment System Development at Audi explained: “This particulate filter is an example of our pursuit of innovation for everyone’s benefit and a successful collaboration with specialised suppliers. We are already doing a lot today on our own initiative. We anticipate it will also become a legal requirement in the future.”
How does it work?
The filter is integrated into the vehicle’s existing airflow in front of the radiator so that only a few modifications to the car are necessary, keeping costs down. The filter element is controlled via the switchable cooling air inlet and its mechanical function is comparable to that of a vacuum cleaner. By a similar principle, the fine dust particles remain stuck in the filter and the air can still flow through it.
Thus far, the filter has been used in Audi e-tron test vehicles. While driving, it passively filters by means of the movement of the vehicle; air flows through the filter system, which captures even the smallest particles. Another possibility is filtering during stationary charging. A fan that is already built into every electric vehicle conveys ambient air through the radiator – the system takes advantage of this process and can thus actively filter the air flowing through it, using the fine dust filter, ensuring the smallest particles are absorbed, even when stationary. This is ideal for use in urban environments, where the particulate matter pollution is much higher than in rural areas.
No impact on the vehicle health
The assessments conducted on the test vehicles were not only used to analyse the effectiveness of the filters, but also to determine whether the technology affects overall vehicle usage. After over 50,000 kilometres (31,068 mi.) of endurance tests on the Audi e-tron, the answer was clear: the filters have no negative effect on the operation of the electric vehicle, including on hot summer days or during fast charging.
The system is so effective that, depending on the usage scenario, the Audi e-tron particles are completely filtered out in a highly polluted city such as Stuttgart. In polluted cities, fine dust emissions can be actively and passively absorbed by up to three vehicles in a typical customer scenario. To make the system even more efficient, Audi is working with MANN+HUMMEL to connect with existing sensors such as weather stations, plus they plan to develop a display logic in the vehicle, allowing passengers to determine when the system is active and how much has already been filtered.
The filter is easy to maintain and must only be replaced when the regular service interval has been reached. A lifecycle analysis of the entire filter system has shown that it will account for 14.9 kilograms (32.8 lbs.) of CO2 equivalents. Additionally, the filter itself consists of 15% recycled material and the entire system is 60% recycled.