Tight coupling diesel engine exhaust aftertreatment system and method

Abstract

The invention discloses a tightly-coupled diesel engine exhaust aftertreatment system, belongs to the field of diesel engine aftertreatment devices, and solves the problems that the treatment effect is affected and the installation is inconvenient due to the fact that the temperature of an exhaust inlet is too low during low load in an existing aftertreatment system. The system comprises a first-stage after-treatment unit, a second-stage after-treatment unit and a third-stage after-treatment unit, the first-stage after-treatment unit is installed at an exhaust outlet of the diesel engine in a coupling mode, and a front-stage diesel oxidation catalyst and a front-stage selective catalytic converter are sequentially packaged in the first-stage after-treatment unit in the exhaust direction. And a post-stage selective catalytic converter and an ammonia gas catcher are sequentially packaged in the second-stage post-treatment unit along the exhaust direction. According to the diesel engine exhaust aftertreatment system, a three-level system framework is adopted, and reasonable installation and efficient matching of the aftertreatment system on a whole vehicle are achieved. The invention further discloses a tight coupling diesel engine exhaust aftertreatment method, and the exhaust aftertreatment effect is effectively improved.

Description

technical field [0001] The present invention relates to a diesel engine aftertreatment device, and more particularly, to a tightly coupled diesel engine exhaust aftertreatment system and method. Background technique [0002] For conventional China VI emission light-duty vehicle diesel engines, the technical routes generally adopted for after-treatment are: 1. Adopt high and low pressure EGR, and the after-treatment system adopts DOC+SCRF+SCR+ASC; 2. Use high-pressure EGR, and the after-treatment system adopts DOC +SCR+ASC+DPF. like figure 1 As shown in the figure, when the aftertreatment system unit is installed in the whole vehicle, it is usually packaged as a whole, that is, the first level package, which is installed on the chassis of the whole vehicle. The turbocharger is connected to the aftertreatment through a connecting pipe, or the diesel oxidation catalyst is coupled. Installed on the engine, and the rest of the catalytic converters are generally packaged and arr...

AI Technical Summary

Problems solved by technology

In addition, for light vehicles such as pickup trucks, the single-stage post-processor is too large and long, making it difficult to arrange it on the chassis. The main impact is that the ground clearance cannot meet the demand, or it interferes with the chassis operating mechanism and other factors.

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