Exhaust gas recirculation cooler

Abstract

The invention provides an EGR cooler comprising tubes (3) and a shell (1) enclosing the tubes (3); cooling water (9) is supplied into and discharged from said shell (1); exhaust gas (10) is guided from a diesel engine into the tubes (3) for thermal exchange of the exhaust gas (10) with the cooling water (9). A bypass flow path for guiding the cooling water (9) is constituted within the shell (1) so as to prevent stagnation of the cooling water (9) in the shell (1).

Description

technical field [0001] The invention relates to an exhaust gas of a recirculating diesel engine, attached to an exhaust gas recirculation (EGR) device for reducing the generation of nitrogen oxides, and an EGR cooler for cooling the exhaust gas for recirculation. Background technique [0002] As a conventionally known technology, there is an EGR device that recirculates part of the exhaust gas of an engine such as an automobile and reduces the generation of nitrogen oxides in the engine. However, in such an EGR device, when cooling the exhaust gas recirculated in the engine, in order to By lowering the temperature of this exhaust gas and making its volume smaller, the combustion temperature is lowered and the production of nitrogen oxides is effectively reduced without excessively reducing the engine output. The EGR cooler for exhaust gas is a known technology, such as disclosed in Japanese Patent Application Laid-Open No. 2001-74380. [0003] figure 1 and figure 2 It is...

AI Technical Summary

Problems solved by technology

[0016] However, in the case of the EGR cooler of the third example, even if a plurality of tubes 33 are arranged in multiple circles at intervals centered on the axis O of the housing 31, the high-temperature exhaust gas 40 flowing from the exhaust gas inlet 37 still has Most of them tend to flow through the tube 33 on the central side, so the temperature of the tube 33 on the central side is higher than that on the outer peripheral side, and there is still the possibility of local thermal deformation. At the same time, it also brings about the problem of deterioration of the heat exchange rate.

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