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Highlights: [•] Highest biodiesel blends result in increased SOF’s percentage to the DPM. [•] O-D SOF and inorganic ions seen not to be affected by the fuel change. [•] F-D SOF was the major constituent comprising 70–90% of total SOF. [•] DPF equipped vehicles exhibited lower oxidation activity per km compared to V2. [Copyright &y& Elsevier]

Highlights: [•] Tested Euro 4+ vehicles with 3 different exhaust aftertreatment systems. [•] Different diesel–biodiesel blends used over 4 different driving modes. [•] Limited increases observed in CO2 with the biofuel blends. [•] Both NO and NO2 increased with the concentration of biofuel in the blend. [•] Biodiesel decreased solid particles number and size in nonDPF equipped vehicle. [ABSTRACT FROM AUTHOR]

Abstract: Biodiesel (fatty acid methylesters) blends with fossil diesel at a mixing ratio between 0.5 and 5vol.% are widely offered as automotive fuels in Europe. The target for the future is to bring this ratio to at least 10%, in order to increase the share of renewable energy in transport. There is however limited evidence on the effects of such blends on the combustion and emissions of diesel engines not originally designed to operate on biodiesel blends. In this study, a number of experiments with 10 vol.% (B10) biodiesel fuel of palmoil origin were performed on a light-duty common-rail Euro 3 engine. The measurements included in-cylinder pressure, pollutants emissions, and fuel consumption. Combustion effects were limited but changes in the start of ignition and heat-release rate could be identified. Emission effects included both higher and lower smoke and NOx, depending on the operation point. The results on the engine bench were compared against a Euro 3 common-rail light-duty vehicle driven on the chassis dynamometer, in order to include the effects of emission control systems (EGR and oxidation catalyst). In addition to the palm biodiesel, an RME-diesel blend was also tested to examine the effects of a fuel with different characteristics. Both biodiesel blends reduced PM emissions and only marginal effects on NOx over the certification test could be identified. The results of this study show that up to 10% biodiesels could be used on current diesel vehicles, without significantly affecting vehicle emission performance. [ABSTRACT FROM AUTHOR]

Abstract: Biodiesel use as an automotive fuel is expanding around the world and this calls for better characterisation of its impact on diesel combustion, and emissions. A neat soybean-oil derived biodiesel (B100) and its 50vol.% blend with petroleum diesel (B50) were used on a Euro 2 diesel passenger car. Measurements of CO2, CO, HC, NO x , PM, particle number and size distribution and carbonyl compounds (aldehydes and ketones) were conducted on a chassis dynamometer. Acceleration tests were performed, fuel consumption was calculated and measured and metals concentration in the lubricant was determined, in order to assess the biodiesel impact on engine performance and wear. Tests were conducted over the certification cycle and real-world driving cycles. Results showed that biodiesel presence had a negative impact under cold start conditions on both regulated emissions and fuel consumption. However the picture was different in the case of warm start real-world cycles, where differentiations were limited and in several cases biodiesel had a beneficial effect on emissions and efficiency. Regarding particle number, solid particles decreased with biodiesel but total particles increased. Certain carbonyl compounds were also increased with B100. Overall, biodiesel at high blending ratios may strongly impact emissions, in a rather non-uniform manner, with the actual effect being dependant on driving conditions and blending ratio. Some of the differentiations observed were not expected when compared to similar results presented in the literature. However this study does not reach definitive conclusions but rather presents a case that may appear in the European passenger car fleet, which requires further attention and research. [Copyright &y& Elsevier]

Abstract: The effect of biodiesel on emissions of diesel passenger cars is a combination of the fuel properties, the blending ratio, and the vehicle technology. In this study, saturated and unsaturated biodiesel fuels were tested neat (B100) and in 30% blend with fossil diesel (B30) on two Euro 3 diesel passenger cars of different engine technologies, namely common rail and unit injector. The measured dataset is enlarged by introducing B10 results from an earlier study in order to produce generalized conclusions over a wider range of blends. None of these vehicles was equipped with a particle filter and different conclusions might be reached for filter-equipped vehicles. The results indicate that the influence of biodiesel on pollutant emissions primarily depends on the blending ratio and secondly on the level of unsaturation and engine technology. Tailpipe CO2, NO x and PM emissions with biodiesel varied from −1% to +3%, −1% to 14%, and −18% to −35%, respectively, compared to fossil diesel. The difference over fossil diesel generally increased with an increasing blending ratio. CO and HC emissions increased over the fossil diesel but remained at low levels and did not threaten the compliance of the vehicles with their respective emission limits. Use of biodiesel on the common rail vehicle led to a smaller NO x increase and a higher PM reduction than in the unit-injector case. The unsaturated fuel generally led to higher NO x emissions from both engine technologies. However, the maximum blending ratio of saturated biodiesel is limited to around B30 due to cold-flow limitations. Hence, the saturated vs. unsaturated species ratio should be carefully designed in market fuels in order to optimize environmental and operational benefits. Overall, it appears that blends up to 10% v/v may be introduced with limited urban air quality implications. [Copyright &y& Elsevier]

Abstract: This study investigates the impact of mid-high biodiesel blends on the criteria and PAH emissions from a pick-up diesel vehicle. The vehicle was a Euro 4 (category N1, subclass III) compliant common rail light duty vehicle fitted with a diesel oxidation catalyst. Emission and fuel consumption measurements were performed on a chassis dynamometer using constant volume sampling (CVS) technique, following the European regulations. All measurements were conducted over the NEDC and Artemis driving cycles. Aiming to evaluate the fuel impact on emissions, a soy-based biodiesel, a palm-based biodiesel, and an oxidized biodiesel obtained from used frying oils were blended with an ultra low sulfur diesel at proportions of 30%, 50% and 80% by volume. CO2 emissions and fuel consumption exhibited increases with biodiesel over all driving conditions which ranged up to 5%. NO x emissions were found to be above the Euro 4 limit and increased with biodiesel between 5% and 10% except for the blends prepared with the palm-based methyl ester. The emissions of PM, HC, and CO decreased with the addition of biodiesel reaching maximum reductions in the order of 10%, 30% and 20% respectively; however, some increases were observed over the NEDC which may be attributed to cold-start. Sharp increases in most PAH, nitro-PAH and oxy-PAH compounds were observed with the application of biodiesel. These increases were particularly noticeable with the use of the oxidized blends, a phenomenon that it is related with the type and quality of this fuel. The emissions were also affected by the operating conditions of the engine. It was found that most PAH compounds were decreased as the mean speed and load of the driving cycle increased. [Copyright &y& Elsevier]

Abstract: This study investigates the impact of low concentration biodiesel blends on the regulated and particle-bound polycyclic aromatic hydrocarbon (PAH) emissions from a modern passenger car. Emissions measurements were performed on a chassis dynamometer using constant volume sampling technique, following the European regulations. All measurements were conducted over the New European Driving Cycle (NEDC) and the Artemis driving cycles. Aiming to evaluate the fuel impact on emissions, a soy-based, a palm-based, and a rapeseed oil based biodiesel were blended with diesel fuel at proportions of 10, 20, and 30% by volume. The emissions of PM, HC, and CO decreased with biodiesel over most driving conditions. Some increases were observed over the NEDC, which may be attributed to the cold-start effect and to certain fuel characteristics. NOx emissions increased with biodiesel and strongly were dependent to the degree of unsaturation of the fuel. CO2 emissions and fuel consumption followed similar patterns and increased with biodiesel. PAH emissions presented discordant results, leading to the hypothesis that the influence of biodiesel source material was particularly strong on the formation of these pollutants. Both increases and decreases were observed in PAH, nitrated PAH and oxygenated PAH compounds with the use of biodiesel blends. [Copyright &y& Elsevier]

This article examines the effect of biodiesel blends on the exhaust aerosol from a Euro 3 passenger car. Five different feedstock oils (soybean, palm, sunflower, rapeseed, and used frying oil) were used to produce fuels with 10% vol. content in biodiesel (B10). Use of the B10 blends led to a systematic reduction of PM mass emissions in the range of ∼9% (rapeseed) to 23% (used frying oil) on average. The combination of particle size distributions based on the aerodynamic and the mobility diameters led to the estimation of the fractal dimension (DF) for non-volatile particles. This was found to range from 2.52 for the baseline (fossil) fuel to 2.62 for the palm oil blend, suggesting that biodiesel can affect the particle morphology, even at this low blending ratio. The differences were statistically significant. The increase of the DF is translated to more compact particle structure, which in turn denotes lower specific surface area. The volatile fraction of PM lies within a range of 1-9% when fossil diesel fuel is employed. Use of palm, sunflower and rapeseed B10 blends results to PM that contain up to 28% volatile particulate mass. The higher emissions of volatile components together with the lower specific area of non-volatile particles, promotes the formation of volatile particles, especially at high speed conditions. This increases the total particle population under motorway driving by up to three times over the baseline levels. [ABSTRACT FROM AUTHOR]