为了研究不同排气热管理方案对柴油机性能和排放特性的影响，针对不同工况选择满足DPF再生温度需求且性能更优的热管理方案。以柴油机及后处理系统为研究对象，研究了1 200 r/min中低负荷工况及800~1 000 r/min低怠速工况下排气节流、进气节流及后喷对车用柴油机排气温度、燃油消耗率及排放污染物等的影响。结果表明：1 200 r/min中低负荷下仅采用进/排气节流方案，排气温度就能满足DPF主动再生目标温度要求；而低怠速工况需采用进/排气节流结合缸内后喷方案才能满足DPF主动再生目标温度要求；最低怠速800 r/min工况采用排气节流结合缸内后喷方案，最高排气温度可提升到254 ℃。相同排气温度下，1 200 r/min中负荷下排气节流方案在燃油消耗率及NOx排放方面表现更优，随着负荷率降低，进/排气节流方案在燃油消耗率及NOx排放方面逐渐接近；1 200 r/min低负荷下进气节流方案在燃油消耗率及NOx排放方面表现更优，相比排气节流方案燃油消耗率降低12%以上，NOx比排放降低32%，但在烟度、THC排放控制方面处于劣势；怠速工况，相同排气温度下进气节流加缸内后喷方案的THC排放是排气节流加缸内后喷方案的2倍左右，且随着后喷油量的增加，排气节流方案较进气节流方案在烟度和THC方面的优势更加显著。各试验工况下，相同排气温度时排气节流方案的过量空气系数及进气歧管压力更优。

In order to study the influences of different exhaust thermal management schemes on the performance and emission characteristics of diesel engines, the thermal management scheme that can meet the DPF regeneration temperature requirements and has better performance was selected for different operating conditions. The effects of intake and exhaust throttling, and post injection on the exhaust temperature, specific fuel consumption rate, and pollutant emissions of automotive diesel engines were studied under the operating conditions of low idle from 800 r/min to 1 000 r/min and low-to-medium load at 1 200 r/min by using diesel engines and after treatment systems as research objects. The results show that either intake/exhaust throttling schemes can achieve the required exhaust temperature for DPF active regeneration at low-to-medium loads of 1 200 r/min. Under low idle conditions, a combination of intake/exhaust throttling and in-cylinder post injection is necessary to meet the DPF active regeneration temperature target. At the minimum idle speed of 800 r/min, using exhaust throttling combined with post injection can increase the maximum exhaust temperature to 254 ℃. At the same exhaust temperature, the exhaust throttling scheme yields lower fuel consumption rate and NOx emissions under medium load at 1 200 r/min. As the load rate decreases, the fuel consumption and NOx emissions of intake/exhaust throttling schemes become comparable. Under low load of 1 200 r/min, the intake throttling scheme offers superior specific fuel consumption and NOx emission by comparing to exhaust throttling scheme, which decreases by more than 12% and 32% respectively. However, the intake throttling scheme performs worse in controlling smoke and THC emissions. Under idle conditions, the intake throttling with post injection scheme produces approximately twice the smoke and THC emissions of the exhaust throttling with post injection scheme at the same exhaust temperature. Furthermore, the advantage of exhaust throttling scheme over the intake throttling scheme in reducing smoke and THC becomes more pronounced as the post injection quantity increases. Under all tested conditions, the exhaust throttling scheme can achieve more favorable excess air coefficient and intake manifold pressure at the same exhaust temperature compared to other schemes.