The new Euro 7 limits, which will apply to newly registered vehicle types from November 2026, will also set particle limits for non-exhaust emissions such as tire and braking systems for the first time. After 2026, these requirements will also become relevant for the aftermarket.

As well as setting particle emission limits for all new type approvals, the corresponding European Regulation 2022/0365 (COD) also requires emission test for braking components that are offered as replacement parts for these new vehicles. The specifications required for the system used to measure particle emissions are defined in the Particle Measurement Programme – Global Technical Regulation 24 (PMP-GTR24).

Bosch has already equipped a brake test rig with the appropriate measurement technology and has been carrying out particle emissions tests for braking systems since the end of 2022. This test system allows to determine when and under what conditions particles are generated by the braking system during driving.

To understand the emissions behavior of brake components over the entire test cycle, Bosch has equipped its brake test rig with measurement technology that far exceeds the requirements of the Euro 7 standard. As well as measuring the size of PM₁₀ and PM_2.5 particles, the test stand also calculates emissions of ultra-fine PM₁ particles.

In addition to determining total particle emissions, the measurement technology used in the Bosch brake test stand can also determine the particle size distribution between ten nanometers and ten micrometers at any time during the test cycle.

This high-precision system provides Bosch engineers with detailed information on emissions behavior in a multitude of different driving situations. It took more than a year to design and develop the brake test rig upgrade, including the special measurement technology. In total, the company invested more than €1 million in the project.

As well as helping to meet future emissions limits, the tests are also designed to reduce emissions of ultra-fine particles, which are particularly harmful to health and are not yet included in Euro 7 regulations. The test results will also be used to make further improvements to Bosch brake pads and discs, which will ultimately help to reduce particle emissions on the roads.

In addition, research has shown that brake pads and discs that emit fewer particles have significantly lower wear rates. Compared with conventional brake pads, which have to be replaced several times over the life of a vehicle, alternative pads that emit fewer particles are likely to last longer between replacements.