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An arrangement for cooling of recirculating exhaust gases of an internal combustion engine

IP.com Disclosure Number: IPCOM000126399D
Publication Date: 2005-Jul-15
Document File: 2 page(s) / 31K

Publishing Venue

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Abstract

Conventional internal combustion engines equipped with EGR have a lower efficiency than internal combustion engines without EGR. This depends mainly on that the recirculating exhaust gases are not cooled to the same low temperature as the air supplied to the internal combustion engine. According to the invention, the recirculating exhaust gases are compressed in a compressor such that they obtain a higher pressure and a higher temperature. An EGR-cooler cools the recirculating exhaust gases by means of a cooling liquid of a cooling system, which cools the internal combustion engine. Thereby, the temperature of the recirculating exhaust gases may drop to a level in the vicinity of the temperature of the cooling liquid. After that, a turbine expands the recirculating exhaust gases. The temperature of the recirculating exhaust gases drops further. In this stage, it is possible to drop the temperature of the recirculating exhaust gases to the same temperature as the air supplied to the internal combustion engine.

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An arrangement for cooling of recirculating exhaust gases of an internal combustion engine

In conventional EGRarrangements, the recirculating exhaust gases of the internal combustion engine are cooled in an EGR-cooler by means of a cooling liquid of a cooling system, which cools the internal combustion engine. Consequently, it is possible to cool the recirculating exhaust gases to a temperature in the vicinity of the temperature of the cooling liquid, which may be in the range of 80-100°. Due to the high temperature of the cooling liquid, it is not possible to cool the recirculating exhaust gases to the same low temperature as the air supplied to the internal combustion engine. As a consequence, the mixture supplied to an internal combustion engine with EGR has a higher temperature than the air supplied to an internal combustion engine without EGR. Therefore, the efficiency of an internal combustion engine with EGR becomes lower than the efficiency of an internal combustion engine without EGR.

The object of the invention is to provide an arrangement for cooling the recirculating exhaust gases to substantially the same temperature as the air supplied to the internal combustion engine in order to accomplish an internal combustion engine with EGR having substantially the same efficiency as an internal combustion engine without EGR. Fig. 1 shows an embodiment arrangement according to the invention. Initially, the recirculating exhaust gases from the internal combustion engine have a pressure p1 and a temperature t1. The arrangement comprises a first EGR-cooler 1, which cools the recirculating exhaust gases by means of a cooling liquid 2 of a the cooling system, which cools the internal combustion engine. The recirculating exhaust gases are cooled to a temperature tc in the vicinity of the temperature of the cooling liquid 2. After that, a compressor 3 compresses the recirculating exhaust gases such that they obtain a higher pressure p2 and a higher temperature t2.

A second EGR-cooler 4 cools the recirculating exhaust gases by means of the cooling liquid 2 of the cooling system. The recirc...