Improving combustion characteristics of diesel and biodiesel droplets by graphite oxide addition for diesel engine applications

Graphite oxide (GO) is an important member of the graphene family of carbon nanomaterials with remarkable physical, chemical, and thermal properties. We conducted an experimental investigation on the combustion characteristics of diesel and biodiesel droplets dosed with 0.1% GO. The fuels were tested by a single droplet combustion experiment in which the temporal variation in the burning behavior of a suspended droplet was captured using a high-speed camera. Numerical analysis of the combustion data suggests that the addition of GO in both fuels resulted in shortened ignition delay (by up to 38.2%), increased burn-rate constant (by up to 29.4%), lowered peak temperature (by up to 7.8%), and shortened burning period (by up to 11.6%). To illustrate, the burn-rate constant increased from 0.68 to 0.88 mm²/second, and the burning period reduced from 2.7 to 2.2 seconds when GO was dosed in diesel. By contrast, the ignition delay and peak temperature both decreased from 1.6 to 1.4 seconds and 659 to 611 K, respectively, when GO was added in biodiesel. Our results suggest that the fuel additive–induced benefits could effectively reduce emissions and improve fuel consumption for diesel engine applications.