Method for lifting locomotive media reductive nitrogen oxide

Abstract

The invention relates to a method for improving efficiency that using catalyst to reduce the nitrogen oxide in vehicle, wherein it comprises: a secondary air feeding tube between the air inlet and the waste gas outlet of engine; at least one electromagnetic valve on the tube, to be controlled by the electric controller, to make the vehicle in low-speed and low discharge temperature start the flux control valve to feed the secondary air to the waste gas outlet, to keep the efficiency that catalyst catalyzes the carbonic oxide and hydrocarbon; and the electric controller has one preset temperature valve, that when then engine discharge temperature is over said valve, the electromagnetic valve will close the secondary air, to reduce the air / fuel ration at the waste gas outlet, to improve the efficiency of catalyst. The invention can improve the transform efficiency of nitrogen oxide (NOx), and reduce the nitrogen oxide content discharge to the air.

Description

technical field [0001] The invention relates to a method for lifting a locomotive catalyst to reduce nitrogen oxides. In particular, a constant speed per hour is set in an electronic control unit to compare it with the engine speed detected by the electronic control unit, so as to control the introduction of secondary air Technology for timing at the exhaust end. Background technique [0002] The locomotive engine in the market, in order to reduce the emission of nitrogen oxides (NO X ) content is mainly to install a catalytic converter in the exhaust pipe of the locomotive engine, and use the rhodium (Rh) precious metal component contained in the catalyst to convert harmful nitrogen oxides (NO) in the exhaust gas. X ) is reduced to harmless nitrogen (N 2 ) and oxygen (O 2 ). [0003] As we all know, the most ideal air-fuel ratio (Air / Fuel) in the general engine operating environment is controlled within a predetermined range around 14.7 (as shown by the slashed area in ...

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Problems solved by technology

[0005] Among them, the installation technology of the catalyst, the traditional method at this stage is to set one or more catalytic converters coated with precious metals such as platinum (Pt), palladium (Pd) and rhodium (Rh) in the exhaust gas. In the pipeline, however, this approach can only improve the conversion efficiency of carbon monoxide (CO) and hydrocarbons (HC) in the exhaust gas. X ) conversion efficiency, the effect is obviously not obvious;

[0006] In addition, there is also a technology of introducing secondary air at present. The method is to introduce secondary air into the exhaust pipe of the locomotive engine before the catalyst carrier, and through the intermittent negative pressure when the engine is running, the fresh air from the outside is introduced into the exhaust. In the trachea, to increase the quantitative oxygen content in the exhaust gas, so that the air-fuel ratio (A / F) of the exhaust gas is greater than or equal to 14.7, so as to promote the conversion efficiency of the above catalyst to oxidize carbon monoxide (CO) and hydrocarbons (HC). However, in In this case, due to the increased oxygen content in the exhaust gas, the air-fuel ratio (A / F) of the exhaust gas passing through the catalyst carrier cannot be less than or equal to 14.7, and the high temperature will be generated during the oxidation reaction of the catalyst, which is not conducive to the catalyst Nitrogen oxides (NO X ) conversion efficiency, so that nitrogen oxides (NO X ) content will only increase and not decrease, which is the main cause of acid rain and damage to the ozone layer. It has a huge impact on the natural environment and needs to be improved urgently

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