Evaluation of Real-World Emissions from Heavy-Duty Diesel Vehicle Fueled with FAME, HVO and BTL using PEMS

摘要

Widespread use of biofuels for automobiles would greatly reduce CO_2 emissions and increase resource recycling, contributing to global environmental conservation. In fact, activities for expanding the production and utilization of biofuels are already proceeding throughout the world. For diesel vehicles, generally, fatty acid methyl ester (FAME) made from vegetable oils is used as a biodiesel. In recent years, hydrotreated vegetable oil (HVO) has also become increasingly popular. In addition, biomass to liquid (BTL) fuel, which can be made from any kinds of biomass by gasification and Fischer-Tropsch process, is expected to be commercialized in the future. On the other hand, emission regulations in each country have been tightened year by year. In accordance with this, diesel engines have complied with the regulations with advanced technologies such as common-rail fuel injection system, high pressure turbocharger, EGR and aftertreatment system. Unfortunately, the engine control system with these advanced technologies is adapted to conventional diesel fuels. Therefore, the use of new fuels to the latest diesel vehicles has a possibility to increase exhaust emissions. From the above background, many researches evaluated emission characteristics of diesel engine fueled with biodiesel such as FAME and HVO in test cells, and indicated the increase in NO_x emission by the use of FAME. As for HVO, it was revealed that the NO_x emission level was almost the same as that of conventional diesel fuel. In order to evaluate the real value of emission characteristic from a diesel engine fueled with biodiesel and disseminate information about environmental impact of biodiesel, it will be necessary to conduct not only evaluation in a test cell but also measurement by on-road driving tests. In this research, real-world emissions from a heavy-duty diesel vehicle fueled with biodiesel such as FAME, HVO and BTL were evaluated by the on-road emission measurement using a portable emission measurement system (PEMS). As a result of statistical analysis of real-world emission data, it was indicated that hydrocarbon biofuels such as HVO and BTL have an advantage of emission characteristics compared with FAME.