The way to improve the efficiency of the neutralization system of nitrogen oxides of diesel internal combustion engines and its efficiency

Abstract

The article analyzes the work of the neutralization systems of nitrogen oxides used on modern trucks with diesel ICE. It is stated that the modern development of technologies for electronic fuel injection and catalytic neutralization of combustion products provides an opportunity to implement the processes of neutralization of nitrogen oxides with an efficiency up to 90%. The most effective method to reduce the exhaust emissions of diesel engines is to purify exhaust gases in the car exhaust system using the SCR-NH3 method. A significant drawback of this system is the presence of a toxic substance ammonia regulated by Regulation No. 49-06. Regulation No. 49-06 provides for the control in operation of emissions of nitrogen oxides by the on-board diagnostics system by introducing emission limit values, but monitoring of ammonia emissions in operation is not provided. It is noted that the state sanitary standards of the Russian Federation and the environmental monitoring service, prescribe in regulatory documents the control of the limit of emissions of harmful substances of ammonia and nitrogen oxides with MPCss 0.04 mg / m3. Thus, an identical approach to limiting these emissions is provided. In order for the purification system to function effectively with ammonia and to support the neutralization reaction, it is necessary to adjust the purification system and maintain the optimum temperature range of operation. It is noted that to ensure a high activity of reduction reactions, it is necessary to adjust the cleaning system and maintain the optimum temperature range of operation, the temperature is about 350-550 ° C. In this regard, the possibility of refining the neutralization system by the injection of urea into the cylinder of an internal combustion engine at the expansion stroke to neutralize nitrogen oxides and reduce ammonia emissions, as well as to increase the efficiency of a diesel engine, using the heat of exhaust gases by creating high pressure in the working cylinder work and boost pressure. When dosing urea solution having a high heat capacity through the nozzle and the subsequent process of expansion of exhaust gases, the temperature value in the cylinder of the internal combustion engine reaches the required value for the reduction reaction. High temperature, ensuring the removal of the reaction products, contributes to the high efficiency of maintaining the process of neutralization of NOx. Intra-cylinder cooling of the engine with urea-injected water solves the problem of thermal stress of the parts of the cylinder-piston group of a highly forced internal combustion engine without a significant increase in heat loss of the internal combustion engine.