Advanced Regeneration Technologies for Diesel EXhaust Particulate Aftertreatment

Title of Programme
Financing Code for Project
Project start year - end year 2000 - 2002
Financing organisation
Coordinator Centro Ricerche Fiat (CRF)
Other partners
Renault Recherche Innovation (RENAULT)
Johnson Matthey PLC (JM)
Zeuna-Staerker GmbH. & Co. KG
Clausthaler Umwelttechnik Institut GmbH (CUTEC)
Politecnico di Torino (POLITO)
Aerosol and Particle Technology Laboratory (APTL)
Budget / APTL Budget ? € / 317,335€
Scientific Manager / Project researcher A. G. Konstandopoulos / D. Zarvalis
Project website
A new kind of filter to remove smoke from the exhausts of diesel engines has been developed by an international team of scientists and engineers. Designed to meet the strict Euro 4 emission regulations that will come into effect in 2005, the filter employs a catalyst to burn out accumulated soot at lower temperatures than usual, minimising the effects on fuel consumption. Cars incorporating a refined version of the new filter are already in production, and the first models will be on sale early in 2004.
Diesels were expected to make up half of all new cars sold in Europe by 2010. Their growing popularity was largely due to their superior fuel efficiency, which also means that they emit less carbon dioxide to the atmosphere than petrol engines. Although modern fuel-injection diesels are much cleaner than those of only a few years ago, they had a reputation for being smokier than petrol engines. The emission regulations Euro 4 that came into effect from 2005, had the permissible emissions of particulates and other pollutants, and had spurred manufacturers into making their diesel engines cleaner still. 
To promote the environmentally friendly diesel, the European Commission has sponsored a cluster of projects known as DEXA (Diesel Exhaust Particulate Aftertreatment). They cover such topics as design and simulation of diesel exhaust systems, methods of measuring particulates, and research on ceramic materials for exhaust filters. One project, Art-Dexa (Advanced Regeneration Technologies), is concerned with developing a new filter to remove smoke from the exhaust.
Maintenance-free filter
Normally the filter temperature would need to be raised to 620-650°C by injecting fuel from the engine, but such high temperatures can greatly increase fuel consumption while the heating is in progress. Existing filters use a fuel additive to help clear out (or ‘regenerate’) the filter at lower temperatures, but the Art-Dexa team wanted a filter that would be completely self-contained and would not need regular maintenance to remove the ashes that are left by the additive. So they decided to use a catalytic coating on the filter. The team tested many different materials to see which was best at removing smoke particles from the exhaust fumes.
Catalyst materials
The partners also screened several different catalyst materials, including some developed within Art-Dexa itself. They settled on three technologies – a noble metal formulation produced by Johnson Matthey, an innovative mixed-oxides formulation developed by APTL, and a perovskite-based technology from Politecnico di Torino. All three were scaled-up into full-sized filters.
Art-Dexa also examined the engine control strategies needed to make the engine and exhaust system work properly during the filter regeneration phase. The engine management also had to account for the accumulating particles in the filter, so APTL provided an algorithm for monitoring the amount of soot.
Both CRF and Renault constructed demonstrator cars equipped with the new technology, and found that the filter increased fuel consumption by less than 2%, a very acceptable figure. The project has been so successful that the research results have already been incorporated into production vehicles, only months after the project was completed in January 2003.