European OEM considerations for aftertreatment systems 

European commercial vehicle manufacturers are preparing for the next phase of emissions regulation. Today, most vehicles operate under the Euro 6 standard, but the industry is already looking ahead.

For OEMs, meeting the next emissions standard will involve more than simply adding new technology. Engineers must balance emissions performance, vehicle packaging, cost and platform design. These factors make aftertreatment systems a key part of vehicle development for the European market.

Cummins works closely with OEMs across Europe, combining aftertreatment engineering and application expertise to develop solutions that address vehicle integration challenges while supporting evolving emissions requirements.

Stricter emissions limits drive technology changes

At its core, the role of an aftertreatment system is straightforward: reduce emissions while maintaining engine performance and efficiency.

Upcoming regulatory requirements in Europe place particular focus on two areas: nitrogen oxides (NOx) and particulate matter. Meeting these limits requires continued development across several aftertreatment components.

For NOx control, selective catalytic reduction (SCR) systems play a central role. To meet stricter limits, SCR catalyst size and overall system volume may increase so the system can process higher levels of NOx coming from the engine. 

Cummins engineers its SCR systems as part of an integrated powertrain solution, helping OEMs achieve strong emissions performance while maintaining engine efficiency.

Particulate matter limits are also becoming more demanding. In addition to reducing overall particle emissions, regulations increasingly address particle size. This places additional importance on diesel particulate filter (DPF) technology and filtration performance. 

Another important factor is exhaust gas mixing. Proper mixing of reductant and exhaust gases helps improve SCR performance and maximize NOx conversion efficiency, while helping minimize particulate formation associated with AdBlue decomposition. Advances in mixer design are therefore an important part of ongoing aftertreatment development at Cummins.

Together, these technologies help reduce emissions while maintaining the reliability and performance that commercial vehicle operators expect.

Packaging remains a major constraint in Europe

While emissions performance drives many technical requirements, packaging constraints often shape the final design of an aftertreatment system.

European commercial vehicles typically operate within tighter chassis layouts and more compact vehicle designs than trucks in some other regions. This leaves limited space for aftertreatment components, particularly as catalyst volumes increase to meet stricter emissions limits. 

Packaging challenges are especially common in medium-duty trucks, light-duty commercial vehicles and urban buses. As aftertreatment systems grow larger to improve emissions performance, engineers must find ways to integrate them into vehicles with limited available space.

Cummins addresses these challenges by offering multiple aftertreatment architectures designed to fit different vehicle layouts while maintaining emissions performance.

OEMs seek solutions that limit vehicle redesign

European manufacturers are also focused on minimizing disruption to existing vehicle platforms.

The commercial vehicle industry is navigating uncertainty as electrification, hydrogen and other alternative technologies continue to develop. In this environment, many OEMs prefer to avoid large investments in redesigning diesel vehicle platforms. 

As a result, manufacturers often prioritize aftertreatment solutions that allow them to maintain existing chassis layouts, share vehicle platforms across multiple models and limit engineering and tooling changes.

Cummins works with OEM customers early in the vehicle development process to design aftertreatment systems that integrate with current vehicle architectures whenever possible.

Modular architectures provide integration flexibility

One way Cummins supports OEM integration needs is through modular aftertreatment system designs. One example of Cummins’ approach to vehicle integration is the U-Module, a compact aftertreatment solution designed to address packaging requirements in commercial vehicle applications. More broadly, Cummins offers different aftertreatment configurations to support varying vehicle integration needs.

Different module configurations allow manufacturers to choose the configuration that best fits their vehicle platform while meeting emissions requirements. These configurations can include single-module systems, U-shaped modules and other modular layouts used across Cummins’ global product portfolio.

This approach gives OEMs greater flexibility when integrating aftertreatment systems into vehicles with limited packaging space, allowing the system architecture to be developed around specific vehicle and application requirements.

For European OEMs facing tight packaging constraints, this flexibility can simplify vehicle integration while supporting emissions compliance.

Thermal management is another key requirement

Beyond emissions and packaging, thermal management is another important factor in aftertreatment system design.

Aftertreatment systems require sufficiently high temperatures to operate efficiently, while European regulations place limits on external surface temperatures to support vehicle safety. As a result, insulation and shielding are often integrated into system design. 

Cummins works with OEMs to support thermal management solutions such as insulation systems, mounting zones and enclosed aftertreatment packaging that help control surface temperatures and simplify vehicle integration.

The importance of a systems approach

Optimizing aftertreatment performance requires coordination across the entire powertrain, particularly as emissions standards evolve. 

Engine calibration, exhaust system design, catalyst performance and thermal management all influence how effectively the system reduces emissions. Because Cummins develops both engines and aftertreatment technologies, engineers can design these systems to work together as an integrated solution.

This systems-level approach helps OEMs balance emissions performance, packaging constraints and overall vehicle efficiency.

Preparing for the next generation of emissions standards

The transition to Euro 7 represents another step in the evolution of European emissions regulations. While the upcoming standard introduces new engineering challenges, it also reinforces the importance of thoughtful system design and close collaboration across the powertrain.

By working with partners like Cummins and taking a systems approach to aftertreatment integration, OEMs can continue delivering reliable, efficient commercial vehicles that meet both regulatory requirements and customer expectations.