Fast removal of pollutants from vehicle emissions during cold-start stage

Abstract

Recently, enormous research passion has been devoted to reduce air pollution caused by vehicle emissions. Effective vehicle emission control method is to convert exhaust pollutants by placing catalyst in the exhaust pipe. However, the major stumbling block is that a large portion of emission occurs in the initial 20–30 s during the engine cold-start stage, before catalyst can reach its operating temperature. To address the challenge, herein we developed a catalyst utilizing Pd and Rh as active components, Ce-Zr solid solution as assistant, γ-Al2O3 as coating and Fe-Cr-Al as supporter. The catalyst component was optimized (atom ratio of Ce:Zr is 6:4, mass ratio of Pd:Rh is 8:2, total weight of Pd and Rh is 1.2 g/L, pore density is 700 pores/inch2) and high-frequency electrical heating technique was employed to decrease operating temperature from 400°C to 350°C and improve exhaust conversion efficiency by 78%.

Keywords

• vehicle exhaust
• emission control catalyst
• high-frequency electrical heating
• engine cold-start stage