013171 Lesson 2 Component Description（013171课2组件的描述）.pdf

Lesson2–ComponentDescription DieselParticulateFilter(DPF) Overview The introduction of direct fuel injection, an increase in systems pressure and advances in engine management Diesel particulate are typically soot particles with systems has significantly improved the performance, adherent hydrocarbons, sulphate and other condensed economy, and refinement of diesel engines. compounds. Legally a particulate is anything in the Also of significance is the reduction of exhaust gas exhaust stream that can be captured on a filter paper at emissions, the maximum levels of which have to be 52º C. continuously improved to meet with changes in Soot particles are called PM (particulate matter). legislation. High injection pressures, nozzle design, Combustion quality is dependent on how the mixture timed commencement of injection and improved of oxygen and fuel, is formed. Soot production is combustion chamber design have lowered the CO, HC, inherent in the diesel combustion process. Particles are and diesel particulate emissions to a large extent. The formed in the rich mixture zones of the combustion Nox emissions produced by an excess of air during process. combustion are effectively reduced by exhaust gas Soot itself has no harmful effects on the human Reticulation systems which are constantly being organism. Pollutants such as Hydro Carbons are optimised. deposited on the soot particles and in this way h