Analyzing the effect of carbon nanoparticles on the combustion performance and emissions of a DI diesel engine fueled with the diesel-methanol blend

With the energy crisis and worsening environmental pollution, methanol, as a carbon-neutral fuel, has become a research hotspot in the field of internal combustion engines. This study discusses the influence of different kinds (graphite oxide, GO; multilayer graphene, MG; carbon nanotubes, CNT) and concentrations of carbon nanoparticles, which do not introduce any new elements, added to the diesel-methanol blend on combustion performance and exhaust emissions in a direct injection (DI) diesel engine across diverse operating load conditions. The results showed that the nano-fuels with carbon nano-additives had a better combustion process, with higher peak cylinder pressure (Pmax) and peak heat release rate (HRRmax), and lower ignition delay (ID) and combustion duration (CD). Moreover, the presence of carbon nano-additives resulted in an improvement in brake thermal efficiency (BTE) and a decrement in the break-specific fuel consumption (BSFC). The nano-fuels with GO showed the best optimization effect on the combustion process, followed by MG and CNT. As for emission, the nano-fuels had fewer emissions of CO, HC, and smoke opacity. The nano-fuels with CNT achieved the most significant decrease in emissions of CO and HC. While the presence of GO had the best reduction effect in smoke opacity. However, there was a slight increase in NOx emission. The experimental findings demonstrate that the utilization of carbon nanoparticles in nano-fuels can effectively enhance the application of methanol in internal combustion engines. •Nano-fuels with graphene oxide, multilayer graphene and carbon nanotubes were tested.•Carbon nanoparticles improve the ignition of the diesel-methanol blend under low load.•Oxidized graphene has the best optimization effects on Pmax, HRRmax, ID and CD.•Nano-fuels shows lower BSFC and higher BTE than the diesel-methanol blend.•Nano-fuels effectively reduce CO, HC and smoke opacity, but NOx will slightly increase.