轻型车燃用费托柴油的实际道路排放特征

Emission characteristics of a light-duty vehicle fueled with Fischer-Tropsch diesel under real-world driving conditions

利用便携式车载排放测试系统,对某款采用增压中冷和高压共轨技术的国Ⅳ轻型柴油车进行实际道路排放测试,研究其分别燃用石油基柴油、费托柴油和混合柴油(费托柴油与石油基柴油按一定比例混合而成)时,不同车速下的CO、THC、NO_x和CO_2排放特征和油耗变化情况。实验结果表明:对于3种柴油,所测4种气态物的排放均随着车速的增加而降低,当速度达到一定程度后趋于稳定;与石油基柴油相比,费托柴油和混合柴油的CO、NO_x和CO_2排放分别降低23%和5%,30%和24%,20%和20%,但THC排放均略有增加;通过碳平衡计算,费托柴油和混合柴油的体积油耗相对石油基柴油分别降低12%和17%。总的来说,燃用费托柴油和混合柴油时的气态污染物排放与石油基柴油具有相似的速度变化趋势,但费托柴油和混合柴油的整体尾气排放和油耗要低于石油基柴油。使用费托柴油或混合柴油是降低轻型柴油车实际道路排放的一个有效途径。

The portable emissions measurement system （PEMS） was used to investigate the CO, CO2, NO, THC emissions and fuel consumption of a light-duty vehicle at various speeds under real-world conditions. The test vehicle equipped with the common rail （CR） , turbocharging and inter-cooling system was compliant with the China IV standards. The vehicle was tested with Fischer-Tropsch synthetic （F-T） diesel first, and followed by the conventional petrol diesel and hybrid diesel （blend of the conventional diesel and F-T diesel） , separately. All the tests were conducted without any modification of the engine. The results show that CO, CO2, NOx and THC emissions factors of the test vehicle with all the three type diesels decreased with the velocity increased and tending towards stability when the velocity was high enough. Significant reduction of CO,NOx and CO2 emissions were observed for F-T diesel and hybrid diesel. For F-T diesel and its blend, the reduction percentages were 23% and 5% for CO,30% and 24% for NOx, 20% and 20% for CO2 emissions, respectively. THC was slightly higher for F-T diesel and hybrid diesel. The volume fuel consumption calculated based on carbon balance of F-T diesel and hybrid diesel reduced by 12% and 17% , respectively. Overall, F-T diesel and hybrid diesel can re- duce the gaseous emissions and decrease the fuel consumption effectively. Using F-T diesel or hybrid diesel is an effective way to reduce the real road emissions of light-duty diesel vehicles.