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Viewing 1 to 9 of 9
2017-04-11
Journal Article
2017-01-9178
Arash E. Risseh, Hans-Peter Nee, Olof Erlandsson, Klas Brinkfeldt, Arnaud Contet, Fabian Frobenius lng, Gerd Gaiser, Ali Saramat, Thomas Skare, Simon Nee, Jan Dellrud
The European Union’s 2020 target aims to be producing 20 % of its energy from renewable sources by 2020, to achieve a 20 % reduction in greenhouse gas emissions and a 20 % improvement in energy efficiency compared to 1990 levels. To reach these goals, the energy consumption has to decrease which results in reduction of the emissions. The transport sector is the second largest energy consumer in the EU, responsible for 25 % of the emissions of greenhouse gases caused by the low efficiency (<40 %) of combustion engines. Much work has been done to improve that efficiency but there is still a large amount of fuel energy that converts to heat and escapes to the ambient atmosphere through the exhaust system. Taking advantage of thermoelectricity, the heat can be recovered, improving the fuel economy.
2008-04-14
Technical Paper
2008-01-0068
Gerd Gaiser, Patrick Mucha, Björn Damson, Josef Rudelt
Active engine-based measures are currently used to assist the exhaust aftertreatment. This paper presents the current predevelopment of a system for active exhaust aftertreatment of diesel engines which enables exhaust aftertreatment to be decoupled from engine-based measures. At the heart of the system, the Fuel Processor is the active component which is used to combust, reactively evaporate or partially oxidise the fuel, as required. Active catalytic converter heating, active particulate filter regeneration or heating of a SCR catalytic converter are possible without engine-based measures.
2008-04-14
Journal Article
2008-01-0809
Patrick Mucha, Gerd Gaiser, Michael Kuehnle
This paper presents a new metallic catalyst substrate design that allows an integrated mixing behaviour and flow homogenisation within the substrate. In addition it offers a high mass transfer from the flow to the interior substrate surface. The design consists of corrugated walls with crosswise orientation of adjacent layers. The walls are permeable so that their high specific surface is directly accessible for the flow and consequently the length for diffusion is reduced and the mass transfer is enhanced. The crosswise corrugated design causes the intensive internal mixing of the flow within the substrate. Thereby local differences in velocity as well as in temperature and in concentration are equalized. Thus the new metallic substrate design concept offers homogeneous reaction conditions throughout the entire substrate. It allows a compact design and in case of a Diesel oxidation catalyst an additional soot reduction due to the design with permeable walls.
2007-04-16
Technical Paper
2007-01-1074
Gerd Gaiser, Christian Seethaler
This study aims at a new concept for a fast catalyst light-off in combining a latent heat storage with a catalyst. The arrangement of a latent heat storage device into the exhaust system offers significant benefits for the catalyst light-off. Different arrangements have been examined. The first arrangement, called the sequential arrangement, comprises a latent heat storage device and a subsequent catalyst. This offers a significantly faster heat up of the catalyst compared to the standard arrangement. By that emissions during the cold start phase can be significantly reduced. The setup of the latent heat storage device is designed for a high heat transfer between storage material and the exhaust gas. A second integrated arrangement of a latent heat storage and a catalyst into one common substrate has also been set up and investigated. The main advantage of this arrangement is that the catalyst itself is kept on its operation temperature during the engine off time.
2007-04-16
Technical Paper
2007-01-0655
Gerd Gaiser, Patrick Mucha, Lorenz Hermann, Michael Kühnle, Daniel Wagner, Klaus Meiser
The work presented here describes the pre-development of a new diesel particulate filter that features an easy set-up. The system is based on a sintered metallic fibre fleece as filtering material. The filter set-up consists of a simple folded arrangement. In this folded configuration the entire filter structure can be set up without one single weld. In addition the filter concept offers a mass flow adapted cross section of the channels which allows very compact filters with a low pressure drop. Another development of the structure with a corrugated arrangement of the filtering walls results in an intensive mixing characteristic of the flow in the structure. By that a homogeneous temperature profile within the structure can be achieved which ensures homogeneous regeneration conditions throughout the structure and thereby avoids partial regenerations.
2004-03-08
Technical Paper
2004-01-1424
J. Oesterle, G. Gaiser, P. Zacke
Based on the results achieved with the progressive spin element in previous work [1], the focus in this paper is on the loading and regeneration behaviour with a spin element during different engine operating conditions and driving cycles. The temperature distribution inside the diesel particulate filter, the ash and soot loading and regeneration behaviour during different driving cycles have been examined. It can be shown that the use of a progressive spin element leads to superior performance of the DPF through better usage of the available filter volume and minimises the disadvantages e.g. for catalytic coated filters concerning aging. Through careful design of the available parameters of the progressive spin element the additional backpressure due to the spin element can be reduced without loosing the positive influence onto the flow distribution.
2004-03-08
Technical Paper
2004-01-0158
Gerd Gaiser, Patrick Mucha
Published investigations on the calculation of pressure drop of diesel particulate filters consider the contribution of substrate, soot, channel flow and inertial effects at the inlet and outlet of the channels. The model presented in this work considers further contributions as the oil ash and additive ash and their effects on the DPF pressure drop. It is shown that different types of ash deposit which are caused by different driving cycles and different regeneration modes, will result in a significantly different pressure drop even at the same total amount of ash. It will be shown that in the case without soot load the ash deposit at the wall will result in a higher pressure drop than the same amount of ash being deposited at the rear end of the channels. It is also shown that at a higher soot load this behaviour will be inverted. In addition this work considers a variable permeability of the soot layer varying with the soot load of the filter.
2003-03-03
Technical Paper
2003-01-1165
B. Damson, J. Rudelt, J. Oesterle, G. Gaiser
Temperature control is essential for lean NOx-catalysts due to their limited maximum working temperature and their fast aging at high temperatures. Therefore, under high load efficient cooling is necessary. On the other hand light-up has to be fast, and cooling under low load has to be small. This can be achieved by switching the exhaust flow between an insulated tube at low temperatures and a cooling element at high loads. Conventional systems consisting of a valve with actuator are expensive and might fail during life-time operation. Therefore, a purely passive flow switch without moving parts was designed. At low exhaust velocities the exhaust gas moves through an insulated central tube, whereas at high exhaust velocities the exhaust gas flows through an outer tube which acts as a cooling element. The switching is characterized by the relative mass flow through the two ways as a function of total mass flow and temperature.
2003-03-03
Technical Paper
2003-01-0840
G. Gaiser, J. Oesterle, J. Braun, P. Zacke
A new concept for achievement of homogeneous flow distributions in catalytic converters and particulate traps is presented. New applications such as NOx-adsorbers, SCR-catalysts and diesel particulate filters call for more homogeneous flow distributions. The new concept of the progressive spin inlet serves for homogeneous flow distribution within a short inlet cone. A spin is imposed on the flow at the outer radius of the catalyst inlet using helical-type flow elements. It is essential that the centre part of the flow is almost free of spin. Best results can be obtained when the spin elements are designed to impose a progressive spin. The combination of a progressive slope angle and a progressive height serves for a relative minimum in pressure drop. It is shown, that the progressive spin element also proves very good results with eccentric arrangements of the catalyst inlet cone. The parameters are optimised using CFD-calculations.
Viewing 1 to 9 of 9