Low Temperature Activity of Euro4 Diesel Oxidation Catalysts: Comprehensive Material Analyses and Experimental Evaluation of a Representative Panel

Abstract

Diesel oxidation catalysts of 16 Euro 4 passenger cars were analyzed and tested on an engine bench to attempt to correlate composition and structure to real-life performances. Particular low temperature behavior was evidenced, which was further studied using simplified gas mixtures on a synthetic gas bench. The long chain hydrocarbons are efficiently trapped, while NO 2 plays a major role in CO abatement before the activation of the catalytic oxidation by O 2 .

Simulating the impact of premixed charge compression ignition on light-duty diesel fuel economy and emissions of particulates and NOx

“…These catalyst units are typically constructed as honeycomb monoliths of wash-coated cordierite on which noble metals such as platinum (Pt) and palladium (Pd) are dispersed. 31 In modern after-treatment trains, DOCs are often located upstream of NO x and particulate control devices because the catalyst can also oxidize NO in the engine exhaust to NO 2 , improving the efficiency of the NO x and particulate removal steps. 32 Details of the simplified DOC model used here are provided in a previous publication.…”

Modeling of diesel oxidation catalysts for calibration and control purpose

“…[11][12][13][14][15][16][17][18] Finally, the effect of the H 2 O adsorption mechanism is also implemented in the model. This is an important phenomenon that can strongly influence the HC adsorption and therefore the general DOC performance, especially during the engine warm-up.…”

“…A split among the different HC species representative of the diesel exhaust gas 7 –18 is summarized in Table 1, while Figure 4 shows an example of different HC adsorption curves used in the analyses presented in the next sections. These curves, representing the HC adsorption as a function of the DOC temperature, have been derived from the available literature 7,8,10 and have shown general validity.…”

“…It must be pointed out that the diesel exhaust gas composition is highly dependent both on the engine operating conditions (speed, load, thermal status) and on the engine calibration; therefore, the HC speciation can vary to a certain extent, consequently influencing the DOC performance. 11 –18 Finally, the effect of the H 2 O adsorption mechanism is also implemented in the model. This is an important phenomenon that can strongly influence the HC adsorption and therefore the general DOC performance, especially during the engine warm-up.…”

Planar Zeolite Film-Based Potentiometric Gas Sensors Manufactured by a Combined Thick-Film and Electroplating Technique

“…Zeolites are microporous, crystalline aluminosilicate materials with an enormous inner surface. Their special framework structure and their associated unique physicochemical properties make them an interesting class of materials that is used for catalysts [ 1 ], ion exchangers [ 2 ], and gas adsorbers, for instance, in automotive exhaust gas aftertreatment applications [ 3 ]. Zeolites are composed of [SiO 4 ] 4− and [AlO 4 ] 5− tetrahedra with the metal ion in the centre being linked to oxygen corners.…”