How the Euro 7 emissions standard is challenging brake manufacturers
The Euro 7 emissions standard also regulates particulate emissions during braking. HELLA is focusing on innovative brake technologies to achieve reductions.
Today around 80 to 85 per cent of particulate emissions from cars can be attributed to tyre and brake wear, and also to road abrasion and the whirling up of dust. For this reason, the new Euro 7 standard regulates not only exhaust emissions and tyre wear, but also the fine dust of particulate emissions from brake systems. The challenge here is to define a measurement strategy that allows reliable comparisons to be made between different vehicles on appropriate test benches. The development of new friction linings and specially coated brake discs ensures a reduction in particulate emissions. The Euro 7 emissions standard will apply from November 29, 2026 for newly type-approved passenger cars and from November 29, 2027 for all newly registered vehicles (Class M1).
What does the new Euro 7 regulation mean?
With the publication of the Euro 7 regulation in the Official Journal of the European Union (2024/1257), the relevant limit values for particulate mass are to apply. For vehicles with combustion engines and hybrid or fuel cell cars, the value is seven milligrams per kilometre. Pure electric cars have lower brake wear as a result of their design. The recuperation of braking energy plays a major role, the brake load is reduced. The limit value here is therefore three milligrams per kilometre. From 2035, the standardised value according to the Euro 7 regulations is to be three mg/km across all vehicle classes.
How is all this checked?
In order to determine brake particle emissions, experts from the UNECE working group "Particle Measurement Programmes" have adopted the UN Global Technical Regulation No. 24 (GTR 24). It comes into its own in independent test centres and in industry. The measurements are carried out on a special brake test stand. This simulates real driving conditions and allows various parameters such as speed, braking force and temperature to be controlled. It involves running through a defined test cycle, the so-called Worldwide Harmonised Light Vehicles Test Procedure Brake Cycle (WLTP Brake Cycle). It includes various braking processes that simulate typical driving situations. During the test itself, which takes place under controlled ambient conditions, the emitted particles are measured. Both the particle mass and also the number of particles are recorded. Fine dust or particulate matter is defined as particles that pass through the size-selective air inlet of a special measuring device that has a separation efficiency of 50 per cent for an aerodynamic diameter of 10 (PM10) or 2.5 (PM 2.5) micrometres (µm) (Source: Federal Environment Agency). PM stands for the Particulate Matter Standard from 1987.
Measurements are also carried out under real driving conditions to further validate the bench tests. The standardised procedures ensure that brake particle emissions are measured precisely and reliably.
Optimum interaction: innovative friction lining formulas and coating concepts counteract the formation of fine dust.
Optimised brakes: less fine dust thanks to innovative materials and coatings
A vehicle must decelerate optimally and comfortably and in the event of danger as quickly as possible. This inevitably creates friction. However, friction not only generates heat, but also causes the friction partners to wear (a phenomenon which particularly affects the brake disc) – in other words: fine dust is emitted. In fact, filtration specialists have already presented filter systems that are arranged around the brake discs and that are designed to catch brake dust. However, it is much more expedient to avoid fine dust in the first place by continuously developing brake components and by using new material compositions. For example, new coating processes for grey cast iron brake discs are used in conjunction with customised friction lining compounds.
HELLA is constantly working on the development of new friction materials and surfaces in order to achieve an optimum balance between brake performance, durability and low particulate emissions in line with Euro 7 regulations. The focus here is on the vehicle-specific demands for the required braking performance – in other words: is it a small car, a mid-range car, an SUV or a "super sports car"?
HELLA started selling brake components under its own brand name on October 1, 2024. Photo: FORVIA/HELLA
Brake components from HELLA: ready for Euro 7!
After FORVIA HELLA took over the HELLA PAGID joint venture at the end of 2023, the sale of brake components under the HELLA brand name began October 1, 2024. The original equipment expertise, for example in the field of brake pedal sensors (brake-by-wire) and also the extensive IAM range of ABS sensors and brake boosters, is now dovetailed with the range of brake-related wear parts and hydraulics. This turned FORVIA HELLA into a full-range brake supplier. The HELLA aftermarket range currently includes around 2,300 different brake pads and also 2,500 different brake discs. HELLA thus covers almost 100 per cent of European vehicle stocks. And against the backcloth of the Euro 7 regulation, HELLA is now focusing on new, innovative brake technologies in order to raise as little dust as possible!