A statistical investigation of biodiesel effects on regulated exhaust emissions during transient cycles

In the present work, a statistical investigation is conducted in order to quantify the effects of biodiesel blending on the regulated exhaust emissions. To this aim, the available literature on biodiesel emissions during transient/driving cycles up to the end of 2011 was gathered and the reported measurements were statistically analyzed with respect to the biodiesel percentage in the fuel blend. From the analysis, collective results, statistical data and best-fit quadratic regression curves are derived based on the emission measurements from all driving cycles. Furthermore, the effects of engine type (heavy or light-duty), dynamometer schedule (chassis or engine), engine model year and biodiesel feedstock are deducted, with separate best-fit curves provided for each case and for each exhaust pollutant. The various trends observed are discussed and explained based on fundamental aspects of diesel engine combustion and emissions. It is believed that the results of this study can prove useful to administrations and international institutions by providing a good estimate of the vehicle fleet’s expected emission changes when running on biodiesel blends over neat diesel, enabling long-term planning and accommodating decision making.

► Gathering all exhaust emission measurements during transient cycles of biodiesel blends.
► Statistical analysis of the gathered data for evaluation of general trends.
► Identifying the effects of engine type and model year, transient schedule and biodiesel feedstock.
► Discussion of the trends observed based on combustion mechanism and emission formation principles.