Materials for thermo management – GTM

In the actual context, European emission standards become particularly severe for motor vehicle air pollution problems (EURO 5 & 6). But emission standards become more and more strict. The evolution from Euro 5 to Euro 6 (2014) aims to reduce NOx by 56% (65% efficiency), while Euro 7 will target an efficiency of 80%.
The actual limitation in efficiency of car exhaust treatment comes from the thermal activation at low temperature.
The GTM (Thermal Management thanks to materials) project aims to maximize the time slot catalytic activity of the post-treatment systems used in automotive vehicles. Today, an increase in pollutant emission at low temperature is observed, due to new combustion processes developed to reduce fuel consumption (lean-burn technologies) and therefore also CO2 emissions. We observe a temperature reduction in modern exhaust line, and this phenomenon has direct consequences on post-treatment systems, unable to operate knowing that they are not in their optimal temperature range. With GTM materials, the temperature ignition will be lowered from 10 to 40%.
Direct pollutants include carbon monoxide (CO), hydrocarbons (HC=propene...) and nitrous oxides (NOx or NO+ N2O +NO2), whereas ozone belongs to the family of indirect pollutants produced in-situ by contact between ambient oxygen, NOx and HC. The most toxic pollutant at the moment is NOx. To reduce the production of NOx, a first approach consists of maximizing the combustion efficiency. Motor management allowed making significant gains in CO2, while reducing the exhaust gas temperatures.
GTM project proposes a passive solution to develop a thermal buffer reservoir (based on SiC) coupled with precious metals coating directly on honeycombs ceramics.
The GTM consortium is composed of complementary teams. It includes Renault, specialized in defining and qualifying exhaust systems, CTI, wash-coater and supplier of ceramic honeycombs and four research institutions, which are complementary in the value chain : CEA (nanomaterials and process), C2P2 (catalysis synthesis), l’ICSM / ISCM (barrier coatings and thermal reservoir) and l’IRCELYON (efficiency characterisation versus CO, HC and NOx abatement).
Experimental and theoretical approaches (thermal simulations) will be implemented so as to be complementary during the whole project. Pre-dimensioning of SiC quantities and the head loss induced will be analysed in relation to the obtained thermal gain. Successive generations should allow improving the striking and the efficiency at high temperatures (hot-start materials), the head loss and the aging properties.

The purpose is to reduce the NOx contents by 80% using the deNOX technologya t a temperature as low as 200°C.
Three different generations of architectures will be developed:

-First generation: Proof of concept.
from the specifications of Renault, the aspect ratio of the structure will be tuned versus the processes used. Validation of the heterostructure. Preliminary validation of the performances (light off CO and HC)

-Second generation: Optimized concept
Experimental data will modify the initial specifications. Whole technical implementation integrated.

-Third generation: Industrial concept.
Final specifications. Optimized architecture and process comparison to industrial throughput.