Regulated and unregulated emissions from Euro VI Diesel and CNG heavy-duty vehicles
本研究比较了欧六标准下柴油和压缩天然气公交车在-7°C至35°C温度范围内的排放，发现两者虽符合欧六但可能超出拟议的欧七限值，尤其氮氧化物和颗粒物。
This study compares emissions from Euro VI-D Diesel and CNG buses across temperatures from −7 °C to 35 °C. Pollutants including NOx, THC, CH 4 , CO, NH 3 , N 2 O, HCHO, Solid Particle Number larger than 23 nm (SPN23) and larger than 10 nm (SPN10) were measured. Both buses complied with Euro VI-D but exceeded European Commission’s proposed Euro 7 limits, notably for NOx and SPN10. The CNG bus also surpassed NH 3 , CO, and CH 4 limits, while the Diesel exceeded N 2 O limits. High NH 3 emissions were observed from CNG (up to 0.320 g/kWh), with Diesel reporting lower levels (up to 0.021 g/kWh). HCHO emission from both vehicles were very low. SPN23 was under limits, but SPN10 exceeded Euro 7 limits at cold start tests. CNG’s CH 4 and N 2 O emissions constituted up to 4.6% and 3.5% of CO 2 equivalent, respectively. Diesel bus showed negligible CH 4 but N 2 O emissions represented up to 37% of CO 2 equivalent.