Effect of altitude on the emission characteristics of a DI diesel engine

To evaluate the effects of altitude on common rail electronic-controlled diesel engine, an experiment was carried out on a test bench with the simulated altitude system. The results indicated that the emissions of CO and Soot increased, while the impact of altitude on NOx varied based on the specific loads and speed when altitude increased from 0m to 4000m. The increment rate of CO and Soot increased with altitude, and the impact of altitude was greater on CO and Soot than those of NOX. The average emissions of CO and Soot increased with altitude, while the average emission NOx first increased at 1000m then decreased with altitude. The average increasing rate of CO ,Soot and NOx was 14.5%~59.5%, 13.4%~25.6% , -5.6%~0.5% respectively.