Heavy-duty diesel engine fuel consumption comparison with diesel and biodiesel measured at different altitudes

This paper devoted to a comparison of fuel consumption of a diesel engine fuelled with diesel and biodiesel. Comparisons were conducted at sea level, 1600 m and 3300 m. A 6.7L, six cylinder turbocharged heavy-duty diesel engine was introduced. The brake specific fuel consumption (BSFC) over the full engine map were measured and plotted. The results indicated that the fuel consumption with diesel fuelling increased with altitude in all the operating conditions except high-speed, high-load mode; while the fuel consumption with biodiesel fuelling mainly increased with altitude under low-speed, low-load and middle-speed, low-load conditions. Under most of the testing conditions, the fuel consumption with biodiesel fuelling was insensitive to the change of altitude. The comparison of fuel consumption between diesel and biodiesel fuelling demonstrated that diesel was still the more economic option for diesel engines operating at sea level. However, biodiesel fuelling could provide a better fuel economy under middle-speed conditions at high altitudes, particularly at 3300 m.