Research on Technical Characteristics of CDPF + SCR for China-III Heavy-Duty Diesel Vehicles Emission Retrofit Based on Remote Monitoring Method

Abstract

Abstract In order to study the technology of reducing heavy-duty diesel vehicles PM and Nox emission, a China-III sprinkler driving on Tianjin expressway was selected to equip with CDPF+SCR for demonstration of PM and NOx emission retrofit. By using the remote monitoring method, the vehicle speed, engine speed, exhaust temperature and pressure drop of upstream and downstream CDPF, NOx concentration upstream and downstream SCR, geographical location and other data were collected and analyzed in real time, and analyze the characteristics of CDPF passive regeneration, SCR conversion efficiency and DPF matching with SCR. The results show that :the idling speed and the middle and low speed operating conditions of the sprinkler are evenly distributed, exhaust temperature at 175∼275 °C accounts for 74%, and CDPF started passive regenerative emission retrofit at 220°C, NOx concentration after installing SCR was mainly concentrated below 800ppm,the average NOx concentration was 620ppm, and the reduction rate of NOx concentration was 51.6%.