Solid SCR (selective catalytic reduction) control system for diesel engine

Abstract

The invention discloses a solid SCR (selective catalytic reduction) control system for a diesel engine, which comprises an ammonia supply system, an ammonia ejection control system, a CAN (controller area network) communication line and a catalyst, wherein the ammonia supply system comprises an ammonia reservoir and a pressure regulation valve; at the normal temperature, NH3 is stored in the ammonia reservoir in a solid mode; after the diesel engine beings to work, engine cooling liquid heats the ammonia reservoir via a cooling liquid pipeline; NH3 in the ammonia reservoir is released in a gas mode so as to reduce NOx in diesel engine exhaust; the ammonia ejection control system comprises an SCR controller, a flow metering control unit and a nozzle, wherein the SCR controller calculates the required ammonia ejection control flow according to the working condition of the diesel engine; the flow metering control unit is used for controlling ammonia flow fed into the ammonia nozzle; meanwhile, a thermal type sensor in the flow metering control unit is used for detecting the actual ammonia flow; the signal is fed back to the SCR controller to carry out feedback control on the ammonia flow; the ammonia is injected into a diesel engine exhaust pipe via the nozzle; and the NOx in the diesel engine exhaust is reduced in the catalyst so as to achieve the purpose of controlling NOx discharge.

Description

technical field [0001] The invention relates to an SCR control system, in particular to a diesel engine solid SCR control system, which belongs to the technical field of automobile emission control. Background technique [0002] With the rapid growth of global motor vehicle production and ownership, motor vehicle pollution has become the main source of air pollution. Especially in areas with a high density of motor vehicles, motor vehicle emissions pose severe challenges to the urban environment. Therefore, taking practical measures to reduce motor vehicle emission pollution is a prerequisite for the sustainable development of the automobile industry. [0003] Diesel engines have less HC and CO emissions, and the key emissions are particulate PM and NOx (nitrogen oxide compounds). However, it is difficult to solve the trade-off relationship between PM and NOx by using traditional internal purification measures, and many internal purification measures are at the expense of ...

AI Technical Summary

Problems solved by technology

The relatively large volume of the urea SCR system limits the application of this technology to light-duty diesel vehicles

In addition, when the exhaust gas temperature is higher than 380°C, the aqueous urea solution sprayed into the exhaust gas stream may be dehydrated quickly and turn into cyanuric acid deposits to block the exhaust pipe, resulting in increased engine back pressure, decreased power, and increased fuel consumption.

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