Effect of glycerine and water emulsion of diesel-biodiesel blends on engine performance and emissions with EGR

Abstract

The globally rising temperatures and its impact on our ecosystem and earth’s natural processes have raised an environmental concern worldwide. The pollution caused due to the burning of fossil fuels has resulted in climate change, thus, compelling the researchers to look for eco-friendly fuels. Biodiesel derived from biomass have emerged recently as a possible fuel due to their role in decreasing CO emissions. However, the excessive production of biodiesel has raised a disposal concern for its by-product glycerine and higher NOx emissions produced through its use has initiated the need to look for other alternative fuels. In the present study, a systematic comparison was performed with multiple blends of diesel-biodiesel and their glycerine emulsions to compare it with water emulsion and investigate the performance and emissions of the related fuels along with the EGR system. All fuel blends and their emulsions were tested on a light-duty and heavy-duty engine. Hydrophilic-lipophilic balance (HLB) was formulated using suitable surfactants to attain the desired stability for various emulsion fuels. Emulsion stability, mean particle droplet size, fuel properties, engine performance, and emissions were observed. It was concluded that brake-specific fuel consumption (BSFC) and brake-thermal efficiency (BTE) increased with the increase in biodiesel and water-glycerine concentration. For emissions, the rise in CO and HC were noted but reductions in exhaust gas temperature, smoke and NOx were observed with emulsion fuels without EGR. Also, there was a significant decrease in smoke (approximately 80%) with increased concentration of glycerine at 3000 rpm, at high load. With the use of EGR, an increase in BSFC and decrease in BTE was observed. Additionally, EGR was seen to increase smoke, CO and HC emissions but lowers NOx and exhaust gas temperatures. The reduction of NOx in B100 was 20.41% and 16.39% when compared to water emulsion and glycerine emulsion at 10% concentration without EGR, and this reduction continued to 44.07% and 43.25% at maximum EGR % at 3000 rpm and high load respectively.