FRANKFURT, Germany–Every year, around 10,000 tons of brake dust are produced in Germany. Companies, like Mann+Hummel, are coming to market with filters to restrict this source of pollution.
Regulators in Europe, as ell as in the the U.S. by way of the influential California Air Resources Board, are imposing new regs on brake dust that is spurring on a new segment among supplier companies to develop various filter and trapping systems.
Mann + Hummel has devised a brake dust particulate filter, which is now technically ready for production. The company is currently testing the new filter together with car manufacturers in cooperation with a brake manufacturer. After the usual lead times in the industry, the filters must be adapted to the models – the brake dust filter can be installed in vehicles in two to three years.
How bad is the problem? Measurements in the London Underground, for example, have revealed air pollution with deeply inhalable particles of 500 to 1120 micrograms per cubic meter. The limit of 50 micrograms given by the European Union, which some still regard as still too high, is thus far exceeded.
It is worth noting that while all vehicles create fine brake dust particles, the levels produced by internal-combustion-engine vehicles and trains far exceed that of electric and fuel-cell vehicles. Why? Because most of the braking resistance is recaptured in regenerative braking systems to help power the batteries.
Mann + Hummel says its filters are suitable for all vehicles. The system consists of a robust housing, which attaches directly to the caliper and absorbs the particles formed during braking. According to the company, the new development fits into any available space and can be adapted to different brake sizes and concepts.
M&H engineers rely on a metal fiber fleece as the filter medium. These are corrosion resistant and can withstand the high temperatures that can occur on the brake. There have been extensive tests with downhill runs that have gone well, the company reports. Testing showed that road dirt, a concern when using encapsulated filters, did not inhibit heat dissipation. To increase the filter area, the material in the housing is created in folds and pockets. When the filter is full, it is changed and disposed of, which should be done in the course of the regular vehicle maintenance.
M&H completed a field test lasting a year in which the objective was to actually catch more particulate matter than the vehicles produce. The fine dust predators are equipped with three different filter systems: a particulate matter particulate filter, a novel NO2 particulate matter combination filter for the interior and the brake dust particle filter.
In the future, says M&H, cars could reduce their particulate emissions by filtering particulate matter out of the air as well as catching it directly at the brake. This will lower the emissions of the entire vehicle, which can play an important role if there are stricter limits for particulate matter.