The total amount, as well as the partitioning, of the NO
x
emissions of six gasoline passenger cars and 10 light-duty trucks, all of Euro-2 emission standard, was measured in this study. The ...measurements were carried out in the NEDC and FTP75 cycles, in the German “Bundesautobahnzyklus” (federal motorway cycle) and in Swiss real-world cycles. All the vehicles were provided by private owners and brought directly from the road to the chassis dynamometer. In order to obtain results which are as realistic as possible, no servicing was carried out.
Depending on their mass, gasoline light-duty trucks of the Euro-2 emission standard have a legal HC+NO
x
limit which is 20–40% higher than for gasoline passenger cars of the same generation. The measurements show that light-duty trucks emit about eight times more NO
x
in Swiss real-world cycles compared to passenger cars. However, this cannot be due to the higher engine load alone; there have to be major differences in engine construction, engine tuning or in the layout of the exhaust gas aftertreatment system. It can be observed that the overall catalyst efficiencies of light-duty trucks are substantially lower than those of passenger cars. Apart from this difference in total NO
x
emissions, an interesting difference in the partitioning of NO and NO
2 for passenger cars and light-duty trucks can be observed. On average, about 5.3 mass-percent of the NO
x
emissions from the measured passenger cars are emitted as NO
2, without a clear effect on the velocity pattern driven. In contrast to the behaviour of passenger cars, the measured light-duty trucks show a strong dependence on the velocity pattern. They emit on average 18.4 mass-percent NO
2, but this figure goes up to 38.3 percent for motorway driving. The measurements show that the NO
2 mass fraction depends strongly on the absolute NO
x
emission level: the more NO
x
is emitted, the higher is the NO
2 mass fraction.
The deactivation of catalysts by coke-forming structures in the dehydrogenation of higher
n
-paraffins is discussed. The patterns of coke formation on a catalyst subject to process conditions are ...presented. A mathematical model of the process is described to show its adequacy. A calculation algorithm for the optimum mode of operation of a dehydrogenation catalyst is constructed, and the calculation results are given. Dehydrogenation catalysts of different brands are compared with respect to several parameters (coke formation on catalysts, the yield of the reaction by-product, and the dynamics of temperature rise in the reactor). The model can be used to estimate the efficiencies of catalysts in a cycle and to compare them.
Numerous concerns, including environmental impact and public health issues, drive the urgent need to replace nonrenewable fossil fuels with renewable energy sources, with biomass emerging as a viable ...alternative globally. In this comprehensive review, the urgent need to transition from nonrenewable fossil fuels to renewable energy sources is addressed, focusing on biomass as a global alternative. It examines the role of zirconium‐based catalysts in converting biomass into biofuels and hydrogen. Various biomass extraction methods based on the thermochemical processes (pyrolysis, gasification, hydrothermal liquefaction, hydrocracking, and steam reforming) are explored, including their merits and limitations. Additionally, the properties of zirconium‐based catalysts and their catalytic efficiency in biomass conversion are assessed, highlighting the factors influencing their performance. In this literature review, the promising potential of zirconium‐based catalysts in enhancing the sustainability and efficiency of global biofuel production from biomass is revealed. It underscores the critical role of biomass as a renewable energy source and highlights the significance of zirconium‐based catalysts in advancing sustainable biofuel production. It offers insights into addressing environmental concerns, promoting public health, and supporting the global transition toward renewable energy solutions.
Herein, the diverse world of sustainable fuel production from biomass using cutting‐edge zirconium‐based catalysts is explored. Multiple pathways are discovered that transform organic matter into eco‐friendly fuels, reduce GHG emissions, and enhance energy security. The future of renewable energy is delved into with this comprehensive review.
Various driving conditions determine major changes in IC-engined vehicles polluting emissions. The generalized use of three-way catalysts on gasoline-engined vehicles and, in the near future, ...oxidation catalysts on diesel-engined vehicles, is likely to enable the control of such changes. Thus, the influence of driving conditions on the efficiency of such devices was studied in a research program proposed by RENAULT and carried out in collaboration with LHVP and UTAC. This study was performed using a chassis dynamometer with the measurement of both regulated (CO, HC, NOx) and some non-regulated pollutants (sulphur oxides, aldehydes, monocyclic aromatic hydrocarbons, polycyclic aromatic hydrocarbons, nitrated or otherwise). Simultaneously, the mutagenous properties of such emissions were assessed using the Ames test. Test vehicles were operated under urban cold or hot start conditions (a sub-unit of the European cycle) and under extra-urban hot start conditions( another sub-unit of the European cycle). For the two engine types, the extra-urban cycle raises catalyst efficiency to a maximum: >95% for gasoline cars and ∼ 90% for organic compounds of diesel cars. Conversely, for cold start in the urban cycle, the catalyst-related decrease in pollution levels is less significant. It is of the order of 85% for gasoline-engined vehicles and <40% for diesel-engined vehicles. Finally, for the hot urban cycle, the performances of the catalysts installed on gasoline-engined vehicles are similar to those obtained for the extra-urban cycle. But with diesel-engined vehicles, the efficiency of such a device is close to that obtained for cold conditions. Catalytic post-combustion seems to be an efficient system for reducing the mutageneous effect of emissions, in particular on diesel-engined vehicles.
Les diverses conditions de conduite auxquelles sont soumis les véhicules à moteur thermique déterminent de façon majeure les variations des émissions polluantes. Aussi, l'influence des conditions de conduite sur l'efficacité des dispositifs de dépollution a été étudie au cours dun programme de recherche développé par RENAULT et exécuté en collaboration avec le LHVP et l'UTAC. Cette étude a été réalisée avec des véhicules RENAULT fonctionnant sur banc à rouleaux en mesurant les polluants réglementés et certains polluants non-réglementés. Parallélement, les propriétés mutagènes des émissions ont été appréciées par un test biologique (test d'Ames). Les véhicules d'essais ont fonctionné en cycle urbain moteur froid ou chaud au démarrage et en cycle extra-urbain moteur chaud au démarrage.
