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World over, emission legislations are becoming stringent day by day. India too, is on the road map for more tough emission legislations. 2/3 Wheeler legislations in India are being considered as the most stringent in the world, where as, Passenger Car and light/heavy duty legislations are reaching Euro III and Euro IV limits in the near future. The present paper describes the system concepts to be followed to reach the emission targets, specially for Euro III and Euro IV for passenger cars. That includes necessity for using more advanced engine technologies such as Turbo Charging with Intercooling, EGR (cooled), Electronically Controlled Direct Injection, Common Rail / Pump - Nozzle systems. The new catalyst technologies required and developed for these applications are described. These technologies not only require to offer efficient emission reduction under fresh conditions, but need to meet the targeted results after long aging of over 80,000 km. The paper is divided in two parts.

World over, emission legislations are becoming stringent day by day. India too, is on the road map for more tough emission legislations. 2/3 Wheeler legislations in India are being considered as the most stringent in the world, where as, Passenger Car and light/heavy duty legislations are reaching Euro III and Euro IV limits in the near future. The present paper describes the system concepts to be followed to reach the emission targets, specially for Euro III and Euro IV for passenger cars. That includes necessity for using more advanced engine technologies such as Turbo Charging with Intercooling, EGR (cooled), Electronically Controlled Direct Injection, Common Rail / Pump - Nozzle systems. The new catalyst technologies required and developed for these applications are described. These technologies not only require to offer efficient emission reduction under fresh conditions, but need to meet the targeted results after long aging of over 80,000 km. The paper is divided in two parts.

India, as a major two and three wheeler production center in the world, is also leading with the stringent emission regulations for this segment of the vehicles. Emission legislations were introduced in 1991 and have been progressively tightened since 1996. The present legislations of 2.0 g/km CO, 2.0 g/km HC+ NOx for two wheelers and 4.0 g/km CO, 2.0 g/km HC+NOx for three wheelers, are being considered as the most stringent in the world. In addition, a voluntary emission warranty of 30,000 km by the manufacturers of two and three wheelers and a deterioration factor of 1.2 on the emission norms of the catalyst equipped vehicles, put an additional strain on the catalyst technologies, as well as on the overall vehicle systems. In order to meet these challenges, and with focus on the cost effective solutions required for developing countries like India, new advanced catalyst technologies have been developed with improved performance and even lower precious metal content.

An overview is given on the state of the art of a new catalytic exhaust gas aftertreatment device for diesel engines. The function of a precious metal based, flow-through type diesel oxidation catalyst is explained. Much attention is paid to the durability of the diesel oxidation catalyst and especially to the influence of poisoning elements on the catalytic activity. Detailed data on the interaction of poisoning elements such as sulfur, zinc and phosphorus with the catalytic active sites are given. Finally it is demonstrated that it is possible to meet the stringent emission standards for diesel passenger cars in Europe with a new catalyst generation over 80.000 km AMA aging.

Stringent standards for the emission of particulate matter by heavy duty diesel engines will come into effect in the nineties in the US and are anticipated to come into effect in the same period in W-Europe and in Japan. This has lead most of the manufacturers to intensify the evaluation of exhaust aftertreatment devices. Although particulate filtering systems proved to be valuable in limited fleet applications, the general introduction did not take place because of complicated and limited durability regeneration. Flow-through catalysts which were introduced for passenger cars in 1989 drew a lot of attention for potential heavy duty diesel applications. In this paper the major parameters affecting the performance of these flow-through catalysts and the particularities related to heavy duty diesel application are outlined. The parameters deal with the fuel sulfur content, the test cycles applied, the catalyst formulation and washcoat composition.

This paper reports first results of research and development work to achieve Nox reduction under lean diesel exhaust gas conditions by using a special coated, zeolite based monolith catalyst. Much attention is paid to the optimization of the activated zeolite system and the influence of group Ib and VIII elements of the periodic system. A major part of the paper deals with the influence of hydrocarbons, carbon monoxide, sulfur dioxide and water on the activity of the catalyst. Another aspect discussed is the influence of the residence time of the exhaust gas components. The thermal stability and the influence of poisoning elements on the catalyst performance is demonstrated by model gas reactor tests on oven and engine aged samples. Finally, first results on the performance of the catalyst system in a vehicle dynometer test are given.

Future emission standards for passenger cars are mainly aiming at a stringent reduction of their hydrocarbon (HC) emissions. A key factor to meet these requirements for passenger cars with otto engines and closed-loop three-way catalyst is the improvement of the cold-start behavior of the aftertreatment device. Amongst other concepts HC-adsorber systems have been proposed to cope with this problem. In the present paper, results of a fundamental research program on these molecular sieve adsorber systems are discussed. Model gas reactor experiments were used to select raw materials for hydrocarbon-adsorption capacity. The materials of choice were used either alone or in combination with state-of-the-art three-way catalysts; the performance of these systems was evaluated on two different vehicles according to the FTP 75 cycle. To get quantitative information about the nature of the stored HC, all investigations were supported by a detailed gas chromatographic HC-analysis.

The use of Pd together with Pt/Rh in automotive emission control catalytic converters is discussed. The drawbacks and advantages of Pd are explained for the conversion of CO, HC and NOx. The performance of high loaded Pd-only catalysts is demonstrated in vehicle tests according to the FTP75, ECE and Japan-10-mode procedures. It is shown that the advantageous lean HC-light-off temperature observed with high loaded Pd-only catalyst can also be reached with similar loaded Pt-only catalysts. Various alternative ways to incorporate Pd in multi-brick converters are evaluated in vehicle tests. It is shown that single brick three metal converters with high Pd-content can have advantages over conventional Pt/Rh-three way catalysts. However, the extent of the improvement depends strongly upon the particular application, and with the present trend of increasing Pd-prices these three metal converters might lead to increased precious metal costs over conventional Pt/Rh-catalysts.

The trend towards lower exhaust gas temperatures related to the introduction of modern, highly efficient diesel engines for passenger cars in conjunction with new legislative emission regulations will require the development of amended catalyst formulations. Not only excellent performance for carbon monoxide(CO), gaseous hydrocarbons (HC) and diesel particulates is desired but also the capability to additionally reduce nitrogen oxide (NOx) under lean conditions. Generally, as for the latter a passive system, i.e. without addition of secondary fuel, is most wanted but also an active system, i.e. with hydrocarbon enrichment before catalyst, could be successful provided the penalties in fuel consumption can be kept low. The present paper illustrates further progress in the area of diesel catalysts for passenger cars and introduces a novel washcoat formulation comprising zeolites as hydrocarbon adsorption components.

Research programs were completed for the development of improved Pd-containing three-way catalysts, which were targeting on the future emission control standards for passenger cars. The influence of newly developed washcoat components as well as an improved precious metal location in special architectured washcoats on the catalyst performance is demonstrated by model gas and engine tests. The most promising catalyst systems were evaluated on different vehicles in U.S. and E.U. driving cycles. The results obtained in this study clearly indicate the potential of Pd-based technologies to be a cost effective alternative for Pt/Rh converters.

Catalyst applications for gasoline and diesel engine powered passenger cars and 2-stroke Two- and Three-wheelers are the main focus of this paper. Catalyst durability and deactivating effects are discussed in detail. Experiences on Indian conditions are also included.