Tail gas aftertreatment device, selective catalytic reduction (SCR) front exhaust gas temperature control system and control method thereof

Abstract

The invention relates to a tail gas aftertreatment device, a selective catalytic reduction (SCR) front exhaust gas temperature control system and a control method thereof. The SCR front exhaust gas temperature control system comprises a urea storage device, a urea pump, a urea supply control valve, a urea injector, an exhaust gas temperature sensor and a controller, and further comprises a coolingchannel used for connecting DPF with SCR and allowing tail gas to pass through; the urea ejector communicates with the cooling channel, the urea pump is connected with the urea storage device and theurea ejector and is connected with the controller in a controlled mode, and the urea storage device comprises a non-thermal regeneration urea storage chamber used for storing a urea solution used during non-DPF thermal regeneration and a thermal regeneration urea storage chamber used for storing a urea solution used during DPF thermal regeneration; and the concentration of the urea solution stored by the thermal regeneration urea storage chamber is lower than that of the urea solution used during non-DPF thermal regeneration. With the technical scheme, the technical problems of high complexity and high cost of an SCR front exhaust gas temperature control system in the prior art are solved.

Description

technical field [0001] The invention relates to the technical field of exhaust gas post-treatment of internal combustion engines, in particular to an exhaust gas post-processing device, an exhaust gas temperature control system before SCR and a control method thereof. Background technique [0002] There are two types of purification of diesel engine exhaust: organic internal purification and exhaust post-treatment. The after-treatment devices of diesel engines include DOC (oxidation catalytic converter), DPF (particulate filter), SCR (selective catalytic reduction technology), etc., which in turn In series in the exhaust system of the diesel engine. Among them, DPF is used to reduce engine particulate (PM) emissions. After the DPF has been used for a period of time, the particles adhere to the surface of the DPF, which affects the exhaust flow, increases fuel consumption, and deteriorates the economy of the diesel engine. At this time, it is necessary to remove the PM accum...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a kind of exhaust gas temperature control system before SCR, to solve the technical problem that the exhaust gas temperature control system before SCR in the prior art is more complicated, the cost is higher; The purpose of the present invention is also to provide an exhaust gas Post-processing device to solve the technical problems of complex structure and high cost of exhaust gas post-processing device in the prior art; the purpose of the present invention is to provide a control method that can effectively control the exhaust temperature before SCR

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