In public debate, the greater part of fine dust emissions found in cities is attributed to road traffic. Measures such as driving bans are continually being considered. Fleet operators are increasingly forced to justify themselves and consider their ecological footprint. In this process, the focal point is mostly exhaust emissions.
But the fine dust emissions of a vehicle are not limited to exhaust emissions. Additional particles penetrate the ambient air through braking, tire, and road abrasion. Therefore, the problem of fine dust is independent of the type of drive and also applies to electric vehicles. When there is high air pollution in cities, particles and harmful gases can also penetrate the inside of vehicles. The concentrations of the harmful substances can be particularly high inside vehicles.
Wear abrasion of the brake disks and pads in the braking process generates dust. And this is a significantly higher volume of dust than that generated by exhaust gases. Up to now the greater part of these dust particles have entered the ambient air and have contributed towards the bad quality of air in many cities. Fine particles constitute more than 90% of the brake dust and these fine particles can penetrate deep into human lungs.
It is therefore necessary to consider the overall balance of the fine dust emissions of a vehicle. The emissions in a city are produced by power stations, factories and households. Motor cars, transport vehicles, busses and railways move around frequently in confined spaces during the day. If it were possible to improve the overall balance for the particulate emissions of these vehicles, it would also be possible to reduce the level of air pollution.
MANN+HUMMEL has developed three applications designed to contribute to the reduction of fine dust pollution from vehicles. A filter installed on the roof or underbody of vehicles retains fine dust from the ambient air. A particulate filter on the brake system is designed to prevent brake dust from being released into the environment. Passengers are protected by an NO2 fine dust combination filter. The use of numerous filters could reduce fine dust pollution in a city. As more vehicles are equipped with the filters, more fine dust will be filtered out of the air.
The MANN+HUMMEL fine dust particle filter enables vehicles to compensate for the emissions they release to the ambient air. When fitted, for example, to the roof or underbody of a vehicle, the filter can retain particulates present in the air. For this purpose, fans convey ambient air into the system mounted at the vehicle. This means that vehicles can filter particulates out of the surrounding air even when the vehicle stands still. The filtration specialists use sensors and contact to a network cloud to record and assess the filtration performance and also collect air and weather data.
First tests indicate that the filter retains as many particulates from the ambient air as a vehicle with a modern gasoline or diesel engine emits in the combustion process. It makes sense to fit fine dust filters to vehicles which frequently move around the city. The filter is hardly noticeable on the roof or underbody of transport vehicles, buses, or suburban trains.
Thanks to its robust housing directly next to the brake caliper, the filter acts directly at the point of production to prevent the escape of brake dust particles into the environment. In particular, the filter protects the ambient air from brake dust particles in city traffic where frequent breaking is necessary.
The filter medium is a material resistant to temperature and corrosion that efficiently filters the different particle sizes.
The brake dust particle filter considerably reduces the release of particles to the air directly at the source. The filtration experts have confirmed a significant reduction of brake dust in laboratory tests. They are now testing the performance of the filter under real driving conditions in test drives with Fine Dust Eater vehicles in greater Stuttgart and as part of test projects with partners. The filter can find application in motor cars, commercial vehicles, railway applications and industry with all types of power trains including electric, hybrid, gasoline and diesel vehicles.
In presence of heavy air pollution in cities, significant amounts of particles and harmful gases could possibly enter the interior of vehicles leading to high concentrations of pollutants inside the vehicles. The NO2 fine dust combi filter from MANN+HUMMEL protects the vehicle occupants against the risks to health posed by air pollution.
A particle filter layer coated with ultra-fine nanofibers enables improved protection against fine particulates. The use of different layers of activated carbon enables the filter to offer improved protection against numerous harmful gases such as toxic nitrogen oxides. Due to special coating of the filter also ammonia can be reduced on a higher level, while a biofunctional layer binds allergens and prevents the growth of bacteria. As a result unpleasant odors are reduced.
The NO2 fine dust combi filter is installed in the Fine Dust Eater vehicles. In general, it is suitable for use with all passenger cars, commercial vehicles, the railway sector and industrial applications.
Our newly-developed filter technologies are subject to regular tests. The results from test drives carried out in Germany, India, and China have shown that in city traffic with high air pollution levels, the fine dust particle filter actually filters out more fine dust from the air than the volume of fine dust produced by the exhaust pipe of a vehicle with a modern combustion engine. The fine dust particle filter exceeds the desired separation efficiency of 80 percent of the fine dust (PM10).
The effectiveness of our brake dust particle filter has proven itself under real driving conditions. The filter retains up to 80 percent of the brake dust particles. The temperature stability was confirmed in the course of many alpine drives on the Grossglockner mountain in Austria. We estimate that the service interval will correspond to the service interval of the brake pads. The developers at MANN+HUMMEL are also confident that the product weight will be less than 500 grams.
The use of 5000 StreetScooter delivery vehicles has so far enabled the Deutsche Post DHL Group to prevent considerable quantities of harmful gases such as carbon dioxide and nitrogen oxide as well as noise from entering the environment. Now the problem of particulates has been addressed. Equipped with a fine dust particle filter developed by MANN+HUMMEL, the StreetScooter Work is now the world's first emission neutral vehicle.
Electric vehicles also release particulates into the atmosphere due to tire, brake, and road abrasion and are therefore not free of emissions. Through use of the filter the overall balance of the vehicle in terms of particulates is now neutral. The fine dust particle filter retains as many dust particles as are produced by tire, brake and road abrasion.
The filter modules will initially be fitted to five StreetScooter test vehicles which with immediate effect will enter service in five German city centers. The successful completion of the test could lead to the series implementation of the fine dust particle filter.
The vehicle is completely neutral under consideration of the overall balance of emissions during driving operations: That means
• no carbon dioxide (CO2)
• no nitrogen oxide (NOx)
• no noise
• no particulates.