Tham khảo tài liệu 'new trends and developments in automotive industry part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Automotive Catalysts Performance Characterization and Development 349 chemisorptions of compounds on the surface of the catalyst and due to chemical reactions that produce volatile compounds or inactive phases. The thermal deactivation occurs due to the sintering process and active metal diffusion. The mechanical deactivation is due to the deposition of particles from the gas phase onto the pores and catalyst surface and effects of abrasion caused by mechanical crushing of the catalyst. Figure 2a shows a typical catalyst module formed by a metal housing containing the catalyst. Figure 2b shows a new catalyst and the visual effect of deactivation in a poisoned catalyst is shown in Figure 2c and 2d. The amount of soot deposited in an used catalyst depends of the fuel quality since gasoline contains some amount of contaminants such as sulfur and oxygen and nitrogen compounds. A new catalyst sample is shown in Figure 3a and 3b and Figure 3c shows the clogging of the honeycomb structure caused by the poisoning of the catalyst. Fig. 3. a Photography of a catalyst sample b SEM micrograph of a honeycomb structure c clogging of the honeycomb structure caused by the catalyst poisoning. Beyond the vehicles powered by gasoline there has been a move for the utilization of other types of vehicles that have been developed to use different fuels that produce less CO2 which cause the greenhouse effect. These fuels are the alcohol renewable bio-fuel derived by sugar-cane or corn gases such as liquefied petroleum gas LPG and compressed natural gas CNG or mix of fuels as the used in flex-fuel technology. These alternative fuels have a lower carbon to hydrogen ratio than gasoline producing less CO2 per travelled distance and reduce the needed of fossil fuel consumption Cohn 2005 . 350 New Trends and Developments in Automotive Industry Some technologies have been developed adapting the engine for the mixtures of fuels like gasoline and ethanol with predetermined composition. Moreover .
