Green light for on-road testing of car exhaust particles

Reducing the emissions of internal combustion engines requires not only establishing ambitious targets as a key technology driver, but also developing solutions that can exceed those goals.

In the case of particle emissions, the type and size of the particles present in exhaust can vary substantially depending on driving conditions, making on-road testing as well as laboratory measurements necessary to accurately gauge actual particle composition.

The cutting-edge technologies being developed in the PEMS4NANO project will enable the measurement of particles as small as 10 nanometres, far smaller than screening capabilities of current exhaust-testing systems.

The project’s results will support further research focused on development of low-emission internal combustion engines, while also leading to new commercial laboratory particle measurement systems and compact, portable on-road testing devices for the automotive industry.

“With ever-growing traffic volumes, the air we breathe exposes us to particulate emissions invisible to the naked eye. The PEMS4NANO project addresses these particulate emissions and aims to validate measurement procedures that are robust and reliable for both the development of lower emission engine technologies, as well as serving as a solid basis for future regulatory actions that will have direct positive social benefits,” says project coordinator Marcus Rieker at HORIBA in Germany.

Ambitious targets

The PEMS4NANO consortium is using a unique two-pronged process to correlate vehicle exhaust measurements in the laboratory with comprehensive test data obtained under real driving conditions. These will contribute to compliance with the EU’s Real Driving Emissions testing requirements for car manufacturers.

Researchers are using a combination of physico-chemical and empirical simulations to gather data on particle characteristics, such as chemical composition, morphology and size distribution, which have a significant influence on the resulting exhaust emissions.

This information will provide insights into the aerosol dynamics within the exhaust line system, including the effects of after-treatment technologies, such as three-way catalysts, particle filters and other components designed to reduce particulate matter in exhaust gases.

Significant steps forward

“The main challenges arise due to the unstable nature of the particles, their different agglomeration behaviour and unknown particle characteristics at various extraction points, ranging from the engine cylinder and exhaust system up to where they exit the exhaust pipe,” Rieker says.

“Tracking the particle characteristics and the exhaust gas composition at multiple extraction points offers a significant advancement in enabling the development of robust and reliable measurement systems to further support the development of future low-emission combustion engines.”

Each partner will benefit from the project commercially, he adds. For instance, CMCL Innovations plans to use the know-how gained in PEMS4NANO to advance its digital engineering toolkit for simulating and optimising fuels, combustion modes and emissions in modern internal combustion engine configurations.

Other partners, including HORIBA, TSI and Bosch, also plan to exploit the advancements made in the project to enhance their products and technologies, while IDIADA will benefit through improvements to its testing and homologation services for the automotive industry.