Luxemburg – Road traffic is a major source of particle-based air pollution in cities. It originates from exhaust emissions by internal combustion engines, and from particulate matter produced by wear and tear on brakes, tires and roads. EU-funded researchers addressed this with breakthrough solutions that cut brake-dust emissions by at least 50 percent
Despite lower-emission vehicles hitting the roads, one of the sources of highway air pollution remains constant: brake-dust particles. According to studies, brake wear ranges between 16 percent and 55 percent of total mass of particles amongst non-exhaust road traffic emissions in urban environments.
These tiny particles could negatively impact the environment and also our health.
“Brakes wear out over time and thus produce wear particles. Some of these particles stick to the wheel rim, while some others fall out on the ground or disperse in the air,” said Guido Perricone, material development manager at Brembo.
New materials and systems, lower emissions
Aiming to reduce brake particle emissions by 50 percent, the EU-funded LOWBRASYS project studied brake emissions and developed new solutions using more durable materials for brake discs and pads, and a particle-capturing system for brakes. The novel brake-disc and pad materials can easily be integrated into existing cars during normal maintenance, while new cars could be fitted with the LOWBRASYS low-emission brake solution from the start.
Project researchers developed a ceramic coating for protecting the surface of brake discs and pads.
“Tests demonstrated that our coating material is more durable to wear and reduces the total number of particles by about 90 percent, while also limits the total mass of particles by 25 percent. The discs differ from current technology as they have ceramic coatings on top of conventional cast-iron brake discs,” explained Perricone.
In addition, a braking strategy provided by software on board the vehicle allows a 40 percent reduction in the number of emitted particles and a 20 percent reduction in the overall particulate mass. This is possible by blending the brake action between the front and rear axle to keep the physical parameters triggering the particle emissions as low as possible.