国外SCR系统介绍.pdf

All PACCAR Engines Selective Catalytic Reduction: will utilize SCR Technology for the Environment Business technology to meet 2010 emissions Environmental regulations and concern about clean air impact all of us. requirements and Protecting and preserving the environment is a core value at PACCAR. By 2010 provide customers all PACCAR engines will achieve near-zero emissions of NOx, a greenhouse gas and smog causing compound. increased reliability and fuel economy. Two emissions technologies will be available, Selective Catalytic Reduction (SCR) and in-cylinder, Exhaust Gas Recirculation (EGR). PACCAR has carefully evaluated each technology and concluded that SCR will provide the most fuel efficient and cost-effective solution to 2010 regulations. The SCR system operates downstream from the engine, removing much of the stress and heat rejection related to EGR-only engines to improve reliability and increase fuel economy. How Does SCR Work? SCR is very simple. There are four major components to the SCR system: a Diesel Exhaust Fluid (DEF) tank, a DEF doser, the SCR catalyst, and an ammonia (NH3) catalyst.