Auxiliary heating device for vehicle SCR (selective catalytic reduction) system and heating method

Abstract

The invention discloses an auxiliary heating device for a vehicle SCR (selective catalytic reduction) system and a heating method. The device comprises a tail gas and high-temperature gas mixing device, a signal collecting system, a controller, an ignition module, a liquefied gas combustion device, a combustion device fuel supply system, proportional solenoid valves and an igniter. The heating method comprises steps as follows: the controller judges whether to perform auxiliary heating on the system according to signals collected by the signal collecting system, when heating is required, the proportional solenoid valves are opened, liquefied gas, air and diesel engine waste gas enter the combustion device and are mixed, mixed gas is ignited by the ignitor and combusted to form high-temperature gas, the high-temperature gas enters an exhaust pipe through a mixing device to be mixed with diesel engine tail gas, the temperature of the tail gas is increased, and finally, the SCR system temperature is increased. By means of heating, the problems that the conversion efficiency of the SCR system is low and the exhaust pipe is blocked by sediments when the diesel engine tail gas is at the low temperature are solved.

Description

technical field [0001] The invention relates to the field of engine nitrogen oxide emission control, in particular to an auxiliary heating device and a heating method for a vehicle SCR system. Background technique [0002] SCR (Selective Catalytic Reduction, Selective Catalytic Reduction) technology for vehicles uses NH after pyrolysis of urea on the catalyst carrier 3 As a reducing product, the NO X Revert to N 2 and H 2 O, to reduce NO in exhaust gas X emissions. Under this technology, NH 3 will preferentially restore NO X , without the O in the exhaust 2 reaction, so it is called "selective catalytic reduction technology". [0003] During the actual engine operation, there are many factors affecting the catalytic conversion efficiency of the SCR system: temperature, flow rate, NO 2 concentration, moisture content in tail gas and sulfide formation in tail gas. Among them, temperature is the most important influencing factor. First, during the operation of the SCR...

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Problems solved by technology

[0006] The technical problem to be solved by the present invention is to provide an auxiliary heating device and heating method for a vehicle SCR system, through heating, to solve the problems of low conversion efficiency of the SCR system and clogging of deposits in the exhaust pipe when the exhaust gas of the diesel engine is at a low temperature

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