Exhaust System For An Internal Combustion Engine, and Method For Operating Such An Exhaust System
an exhaust system and internal combustion engine technology, applied in the direction of machines/engines, separation processes, transportation and packaging, etc., can solve the problems of increasing production costs, corrosion problems in the filter structure on which they are applied,
Inactive Publication Date: 2008-01-24
ROBERT BOSCH GMBH
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- Abstract
- Description
- Claims
- Application Information
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Benefits of technology
The invention relates to an exhaust system for vehicles that reduces soot emissions. The system includes two filter devices, with the first device promoting soot burnoff and the second device promoting the oxidation of CO and NO. The first device has a higher corrosive activity than the second device, so a less expensive substrate can be used in the second device. The system is cost-effective and reduces production costs. The method of regenerating the filter devices involves elevating the exhaust gas temperature upstream of the first device to a level that ensures soot burnoff, and then elevating the temperature further upstream of the second device to promote the oxidation of CO and NO. This method can be implemented without the need for a separate heater and is advantageous for reducing emissions in vehicles with diesel engines.
Problems solved by technology
However, it is a problem that many catalytic materials that promote the soot burnoff lead to corrosion problems in the filter structure onto which they are applied.
This necessitates the use of special filter materials, which increases the production costs.
Method used
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Embodiment Construction
[0023] In FIG. 1, an exhaust system of an internal combustion engine 10 is identified by reference numeral 12. It includes an exhaust tube 14, which delivers the exhaust gases from combustion first to a first filter device 16 and after that to a second filter device 18. The engine 10 operates on the diesel principle. Soot particles produced in combustion are at least partially filtered out of the exhaust gas in the two filter devices 16 and 18.
[0024] As FIG. 2 shows, the first filter device 16 includes a housing 20, in which a filter structure in the form of an open-pore ceramic or metal foam 22 is located. The first filter device 16 is accordingly a depth filter. The second filter device 18 likewise includes a housing 24, in which a filter structure 26 in the form of alternatingly closed honeycombs or conduits 28 is located.
[0025] A detail of an internal region of the filter structure 22 of the first filter device 16 is show in FIG. 3. As shown, this filter structure 22 has pores...
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Abstract
An exhaust system of an internal combustion engine includes a first filter device and a second filter device located downstream of the first. Both filter devices filter soot particles out of the exhaust gas. At least the first filter device has a catalytic material, which promotes an exothermic soot burnoff in such a way that as a result of the corresponding heating up of the exhaust gas, the soot burnoff in the second filter device is set in motion. The materials of the two filter devices are selected such that the soot burnoff in the first filter device ensues at a lower temperature and / or at a similar temperature is stronger than in the second filter device.
Description
PRIOR ART [0001] The invention relates first to an exhaust system for an internal combustion engine, in particular in a motor vehicle, having a first filter device and a second filter device, located downstream of the first, which each filter soot particles out of the exhaust gas, and at least the first filter device has a catalytic material which promotes an exothermic soot burnoff in such a manner that as a result of the corresponding heating up of the exhaust gas, the soot burnoff in the second filter device is set in motion. The invention also relates to a method for operating an exhaust system of this kind. [0002] An exhaust system and a method of the type defined at the outset are known from German Patent Disclosure DE 101 56 191 A1. This shows an exhaust system which has a main filter device and a prefilter device preceding it. In both the prefilter device and the main filter device, soot from the exhaust gas is accumulated. For regeneration, the soot accumulated in the prefi...
Claims
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IPC IPC(8): F01N3/021
CPCB01D46/0063B01D46/2418B01D53/945B01D53/9459B01D2255/1021Y02T10/22B01D2255/104B01D2255/915B01D2258/012F01N3/021F01N3/035B01D2255/1023Y02A50/20Y02T10/12B01D46/84F01N3/02
Inventor WIDENMEYER, MARKUS
Owner ROBERT BOSCH GMBH