Gasoline and diesel internal combustion engine (ICE) technology has improved dramatically over the years. Combined with the growing adoption of electric vehicles (EVs), tailpipe emissions are on the decline and scrutiny is shifting towards non-exhaust emissions, such as those from braking systems. Tiny metal particles released into the air have been linked to lung damage and respiratory problems, and regulators are cracking down.
Measuring brake emissions
Euro 7, which is set to take effect in 2025, will mark the first emission standard to limit particle emissions from brakes. Pivotal to that will be establishing an official procedure to measure brake particle emissions under standardised conditions. This is exactly what the United Nations Economic Commission for Europe’s Working Party on Pollution and Energy has been developing, as have various braking experts. For brake suppliers, these coming standards are reshaping current R&D and guiding future product strategies.
Tenneco’s Ferodo OE Braking business is a case in point. It is arguably one of the oldest players on the market, recently celebrating 125 years of operation. Today it is a leading supplier of friction materials, accounting for 40% of the global high-value front brake disc friction market, and boasts the broadest range of friction materials in the world. Over its long history, it has learned the importance of innovation. The Ferodo Engineering team’s efforts are backed by 230 engineers devoted to the global OE market.
Holger Schaus, Vice President, Engineering, tells Automotive World that the company is actively collaborating “with various partners and relevant groups” to get on top of the emissions focus. Regarding new Euro 7 solutions under development, Schaus hesitates to share details publicly but confirms the team is “working with discs and developing new friction material to drastically reduce friction.” He concedes that “automakers will need a solution for this. We have been collaborating with some OEMs for more than three years, focussing on product development and finetuning to improve friction performance. Each OEM has its own philosophy and its own approach.” The company’s current customer list spans most of the major vehicle manufacturers, including Volkswagen, Ford, BMW and Mercedes-Benz, along with new entrants like Tesla and BYD.
Tenneco has also developed a dyno to simulate and measure brake emissions. Validation testing on this state-of-the-art measurement test rig is underway and should accelerate the development of new friction materials that meet Euro 7 requirements. The aim is to receive certification by Q4 2023.
Sustainability within braking goes beyond Euro 7 and emission testing. At Ferodo, it has been a hot topic for years, with considerable effort poured into its low-copper and copper-free offerings. Ferodo introduced its low-copper and copper-free brake pad range for the aftermarket in 2012, followed in 2019 by the technical release of its advanced copper-free hybrid friction material composites for OE vehicle applications.
“California kick-started the move towards low and then zero copper in the product,” explains Neville Rudd, Group Vice President and General Manager of Tenneco’s Global OE Braking business. Research in the US linked brake dust to water contamination and damage to aquatic life, prompting tighter restrictions. “Having that particular issue in one state meant it rolled out across the US, and now it is pretty standard globally to produce friction material products without copper,” he adds. “That’s the basic change we made to make sure no water source becomes potentially contaminated.”
Towards electric and autonomous
Low-carbon mobility is also characterised by growing use of EVs and automated driving. These trends are making themselves felt on the braking front. “Vehicles that use much more regenerative braking [like EVs] mean the value proposition of our product will change,” notes Schaus. “With less braking you will have more corrosion, and you still need to ensure top performance for emergency situations.”
There is also the weight issue: EVs are generally about 19% heavier than their equivalent ICE models due to the addition of the battery pack. “That could mean a shift to a high performance brake,” says Rudd. “Even though the brake would only be used in emergency situations, it’s needed to retard the vehicle speed very quickly.” He also points out that heavier vehicles will need bigger brake pads. Coatings could be another area for further development in the wake of e-mobility. “Automakers are starting to apply various coatings to discs, and that will develop further, particularly with the particle emission reduction targets we are seeing to ensure discs remain clean and there is less wear on discs themselves,” says Rudd.
As for the move to autonomous driving, this could result in more fleet vehicles putting in much higher mileage. “Instead of sitting parked for most of the day, vehicles could be almost constantly in operation. That leads to faster wear of the components,” Schaus explains. For a brake supplier, durability will need to be considered under these harsher conditions.
The good news is that none of these innovations should entail a hefty price increase. “While friction material changes involve significant R&D investment on our part, the pricing impact is relatively small,” Rudd confirms. “Each individual customer is pursuing its own slightly different approach to resolving particle emissions through changes in braking technology. Over the next couple of years, as the most cost-effective solution becomes known, the price impact will depend on each customer’s volumes and how successful their platforms are.”