SCR urea spraying system for dimethyl ether engine

Abstract

The invention provides an SCR urea spraying system for a dimethyl ether engine, and belongs to an internal combustion engine waste gas purification system. The SCR urea spraying system comprises a dimethyl ether fuel tank, a pressure reduction tank, a urea tank, a urea tank switch valve, a urea spray nozzle, an electric control unit and the like. The saturated steam pressure of the dimethyl etherfuel is used for pressurizing the urea tank; the pressure regulation valve is regulated, so that the pressure in the urea tank is constant; the urea tank switch is arranged on a connection pipeline between the urea tank and the urea spray nozzle; the electric control unit sends instructions to control the starting time of the urea spray nozzle, so that the set quantity of the urea solution is sprayed into an exhaust pipe of the engine. The system has the advantages that the structure is simple; the pressure is stable; the spraying metering precision is high; a urea pump is omitted; the cost ofthe SCR urea spraying system is greatly reduced.

Description

technical field [0001] The present invention relates to an SCR urea injection system for dimethyl ether engines, more specifically, to a selective catalytic reduction system (Selective Catalyst Reduction) for reducing NOx emissions from dimethyl ether engines, which belongs to the exhaust gas purification of internal combustion engines system. Background technique [0002] Dimethyl ether is a new alternative fuel for automobiles in recent years. Dimethyl ether, referred to as DME, its chemical formula is CH 3 -O-CH 3 , Dimethyl ether is a colorless, slightly odorous gas with a boiling point of -24.9°C and a saturated vapor pressure of 0.51MPa at ambient temperature. The cetane number of dimethyl ether is greater than 55, which is higher than that of diesel oil. It has good self-ignition characteristics and is very suitable for compression ignition engines. Since the weight percentage of oxygen in the DME molecule is 34.8% and there is no C-C bond, there is almost no soot...

AI Technical Summary

Problems solved by technology

[0005] The disadvantages of the prior art are that the urea pump is used to pressurize the urea aqueous solution, the pressure is adjusted by the pressure control device, and the pressure fluctuation is controlled by the pressure stabilizing device. The system control process is complicated, there are too many parts, and the processing cost is high.

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