Search Results

With the implementation of Euro V emissions legislation in 2010, the vast majority of light-duty diesel vehicles now employ a diesel particulate filter. The expansion of the Diesel Euro V standard outside Europe is inhibited in part by the low availability of ≺50 ppm sulfur fuel. Having said this, countries such as India and China have ≺50 ppm sulfur fuel available in many urban centers today, with the geographical area covered growing each year. Whilst it is well known that diesel DPF applications require ≺50 ppm sulfur fuel for optimum long-term operation, the ability of the system to withstand periodic "high" sulfur events would be a useful enabler for the early implementation of Euro V legislation to these markets. In this paper, the authors set out to assess the capability of the DOC and cDPF exhaust gas aftertreatment system to cope with periodic high sulfur fuel events.

Modern Diesel Engines equipped with Common-Rail Direct Injection and EGR are characterized by an increasingly high combustion efficiency. Consequently the exhaust gas temperature, especially during a cold start, is significantly reduced compared to typical values measured in previous engine generations. This leads to a potential problem with CO emission limit compliance. The present paper deals with an experimental investigation of turbulent-flow metal substrates, carried out on a vehicle roller bench using a production 1.3 Liter diesel engine equipped passenger car. The tested metal supported catalysts proved to yield extremely high conversion rates both during cold start and in warm operation phase. The improved mass transfer efficiency of the advanced metal substrates is related on one hand to the optimized coating technology and, on the other hand, to the enhanced flow performance in the single converter channels which is caused by structured metal foils.

Future stringent emission levels for NOx and PM will lead to the introduction of innovative combustion processes for diesel engines, such as premixed combustion, with the results to enhance the engine out emission of HC and CO. Therefore very efficient oxidation catalyst will be needed to face this possible issue. This paper deals with the optimization of a EU IV exhaust system by means of innovative metal supported catalyst, as for example the Pre Turbo Catalyst and the Hybrid Catalyst in combination with dedicated catalyst coatings. Moreover a base study over the use of PM-Filter Catalyst has been made, to show the efficiency of such a device with EU IV engine calibration. The second part of the paper deals with the turbulent like structured foils substrates to have an even more efficient diesel oxidation catalyst with very high volumetric efficiency.

The regeneration of a loaded particulate filter is one of the biggest challenges in the development of filter systems. The reason is under certain conditions the exhaust gas temperature does not reach the required minimum regeneration temperature for a longer period of time. This paper describes results achieved with a catalytically coated filter alone and in combination with engine parameters, which are used to increase the exhaust gas temperature. The activity of the catalytically coated filter was evaluated by using the well-known balance temperature test. The soot-burning rate was determined at different exhaust gas temperatures. The investigated engine control parameters included intake air throttling and a control of lambda. A special low-temperature transient test was designed to evaluate the regeneration efficiency of the catalytically coated filter and the described engine control parameters under more realistic conditions.

The present work intends to examine the selective NOx reduction efficiency of a current commercial Titanium-Vanadium washcoated catalyst and to develop a transient numerical model capable of describing the SCR process while using a wide range of inlet conditions such as space velocity, oxygen concentrations, water concentration and NO2/NO ratio. The concentrations of different components (NO, NO2, N2O, NH3, H2O and HNO3) were analyzed continuously by a FT-IR spectrometer. A temperature range from 150°C up to 650°C was examined and tests were carried out using a model exhaust gas comparable to the real diesel exhaust gas composition. There is a very good correlation between experimental and calculated results with the given chemical kinetics.