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The clear objective of future powertrain development is strongly characterized by lowest emission impact and minimum overall system cost penalty to the customer. In the past decades emission impact has been primarily related to both optimization of combustion process and exhaust after-treatment system efficiency. Nowadays, weight reduction is one of the main objectives for vehicular applications, considering the related improvements both in fuel consumption (i.e. CO2 production) and engine-out emissions. The state of the art of catalytic converter systems for automotive ZEV-oriented applications has yet to be introduces into mass production. This paper investigates the successful application o metallic turbulent structures for catalytic converters along with innovative packaging considerations, such as structured outer mantle, which lead to significant weight reductions, exhaust backpressure minimization and improved overall emission conversion efficiency.

The use of hydrogen (H2) as a fuel for urban private and public transport may represent a major solution to reduce pollutant emissions and CO2 production in urban areas. Looking for short-term solutions, the introduction of moderate quantities of H2 (up to 30%) into Natural Gas (NG) SI engines may be a feasible solution to get a faster combustion process, and therefore less HC and CO2 emissions, and a slight NOx increase which may be potentially limited by the adoption of lean-burn engine control strategies. However, concurrent effects of volumetric efficiency reduction and maximum temperature in the combustion chamber require a careful optimization of operating conditions to fully exploit the H2 potential and to determine the most convenient H2/NG mixture ratio. In that context, 3D numerical tools may be useful to analyze the effect of H2 introduction on engine performance.

The use of biodiesels is an effective way to limit greenhouse emissions and partly limit the dependence on fossil primary sources. Biodiesel fuels also show interesting features in terms of PM-NOx emissions trade-off that appears more favorable toward an optimized control of the Diesel Particulate Filter (DPF). In fact, the DPF, which is the assessed aftertreatment technology to reduce PM emissions below the limits, suffers from fuel consumption penalization or excessive exhaust system backpressure, as a function of the frequency of the regeneration process. On the other side, issues such as the impact of the higher ash content of biodiesel on the DPF performance have also to be better understood. In the given scenario, an experimental study on a DEUTZ 4L off-road Diesel engine coupled to a DOC-DPF (Diesel Oxidation Catalyst-Diesel Particulate Filter) system is proposed in this paper.

Recent engine development has been mainly driven by increased specific volumetric power and especially by fuel consumption minimization. On the other hand the stringent emission limits require a very fast cold start that can be reached only using tailored catalyst heating strategy. This kind of thermal management is widely used by engine manufactures although it leads to increased fuel consumption. This fuel penalty is usually higher for high power output engines that have a very low load during emission certification cycle leading to very low exhaust gas temperature and, consequently, the need of additional energy to increase the exhaust gas temperature is high. An alternative way to reach a fast light off minimizing fuel consumption increase is the use of an Electrical Heated Catalyst (EHC) that uses mechanical energy from the engine to generate the electrical energy to heat up the catalyst.

Future stringent emission limits both in the European Community and USA require continuously increased conversion efficiency of exhaust after-treatment systems. Besides the obvious targets of fastest light-off performance, overall conversion efficiency and durability, catalytic converters for maximum output engines require highly optimized flow properties as well, in order to create minimum exhaust backpressure for low fuel consumption. This work deals with the design, development and serial introduction of a close coupled main catalyst system using the innovative technology of Perforated Foils (PE). By means of PE-technology, channel-to-channel gas mixing within the metal substrate could be achieved leading to dramatically reduced backpressure values compared with the conventional design.

1 An experimental study has been carried out on a production vehicle by means of roller-bench emission tests in order to optimize alternative aftertreatment systems. To this aim different comparisons between the production exhaust system and new strategies are discussed in the present paper with aid of both modal emission data and bag tailpipe figures. The present work shows the application of a alternative solution that complies with future emission legislation with regard both to HC, CO, NOx and PM without any major engine power output or fuel consumption penalty.

It is well known that the optimal management of cold start is crucial to fulfill present and future emission legislation. During past years the catalytic converter has left its original under floor position to get increasingly closer to the engine in order to exploit higher exhaust gas temperature. Simultaneously, the exhaust gas temperature is becoming significantly lower, both in gasoline engines due to the extensive use of turbo charging, and in diesel engines thanks to very high combustion efficiency and in some cases the use of two stage turbo charging. A well established way to reach the catalyst light-off temperature fast enough to fulfill emission limits consists of artificially increasing the exhaust gas temperature. This has the drawback of a higher fuel consumption which conflicts with the tight CO2 targets now required of the OEMs.

The Environmental Protection Agency (EPA) and California Air Resources Board (CARB) requirements for high mileage durability of emission components make it necessary to ensure the mechanical robustness of metallic catalytic converters. In addition, the robustness of design features must be assessed in the early design development phase without resorting to vehicle fleet testing. By following established reliability methods, a new approach for time and cost efficient accelerated durability testing was developed, which can account for the combined effects of critical stressors of a metallic catalytic converter. This paper describes the methodology used to determine the critical stressors and their levels in actual operating conditions which were determined by analyzing a broad range of vehicle test information. This information was used to develop a temperature profile and a high vibration load profile for the new life test method.

Metal based Diesel Particulate Filters (PM-TRAPs) could represent a short time solution to face with particulate (and NOx) emissions with a small influence on CO2 emission. In fact, the operation principle of the PM-TRAP, based on fluid dynamical behavior of exhaust flow in “ad hoc” shaped geometries, allows to separate the particle content of exhaust-gases but needs to be carefully assessed to optimize filter performances. In this paper a mixed numerical and experimental procedure has been developed; it allows to finely tune the design parameters which can be used to achieve pre-defined targets in terms of particulate matter and fuel consumption. By adopting the previously declared procedure, a PM-TRAP “optimal” geometry has been chosen. Its performance has been verified with respect to experimental data. Results are encouraging and suggest further development of the system.