Abstract Exhaust emissions from Euro 2-6a cars using diesel, gasoline, high concentration ethanol (E85) fuel and compressed natural gas (CNG) were studied comprehensively, with a focus on results obtained at −7 °C test temperature. Higher emissions than desired were noticed in some cases, e.g. elevated methane emissions from natural gas fuelled cars, as well as methane and acetaldehyde emissions from E85 fuelled flexible fuel vehicles. Additionally, mutagenicity of PM samples and oxidative potential of semivolatile samples were observed. However, emission performance improved significantly when moving from older to newer Euro 6a cars, showing that low tailpipe exhaust emissions can be achieved when combining new car technology with CNG, E85, gasoline and diesel fuels. Furthermore, the climate impact of these technologies could reduce by using renewable counterparts of these fuels.

中文翻译：

---

替代燃料汽车尾气的综合排放表征

摘要 对使用柴油、汽油、高浓度乙醇 (E85) 燃料和压缩天然气 (CNG) 的欧 2-6a 汽车的尾气排放进行了综合研究，重点是在 -7 °C 测试温度下获得的结果。在某些情况下发现排放量高于预期，例如天然气燃料汽车的甲烷排放量增加，以及 E85 燃料灵活燃料汽车的甲烷和乙醛排放量。此外，还观察到 PM 样品的致突变性和半挥发性样品的氧化潜力。然而，当从较旧的欧 6a 汽车转向较新的欧 6a 汽车时，排放性能显着改善，表明将新汽车技术与 CNG、E85、汽油和柴油燃料相结合可以实现低尾气排放。此外，