Synergetic effect of hydrogen supplementation with waste cooking oil biodiesel – An assessment of the emission, combustion and performance parameters of a compression ignition engine

Abstract

This investigation aims at examine the effects of hydrogen gas at different flow rates in combination with biodiesel made from used cooking oil on the combustion, emissions, and performance parameters of an engine. In order to improve the thermal performance and combustion characteristics of the stationary engine and lower its emissions, hydrogen is injected through the main manifold at varying flow rates ranging from 3 to 9 LPM, and waste cooking oil biodiesel (WCO B20) is injected through the injector as the main fuel. Both of these fuels are used in conjunction with each other. Results of combustion characteristics revealed that the cylinder pressure enhanced by about 7.32 % using 9 LPM hydrogen flow through the main manifold compared to diesel fuel. Similarly, the HRR from the engine using 9 LPM hydrogen flow enhanced by about 9.43 and 13.76 % compared to diesel and WCO B20, respectively. A comparison is made between diesel fuel and with the proposed modified fuel on the engine's performance, which is assessed in terms of BTE and BSFC. For a range of different engine loads, several emission parameters including HC, NOx, CO, CO2, and smoke opacity are monitored and analyzed for the fuel that has been produced. The results showed that the BTE of the engine is higher in the case of WCO B20 with hydrogen fuel in the flow rate of 9 LPM by about 35.38 % at various engine loads in comparison with the other flow rates of hydrogen fuel, WCO B20 blend, and diesel fuel. Similarly, there is a significant decrease in the SFC by about 17.85 % of the fuel using hydrogen fuel at higher flow rates. The CO emissions with WCO B20 biodiesel blend and diesel fuel are higher, whereas there is a substantial reduction in the CO emission about 22.58 % using a higher concentration of hydrogen fuel along with the WCO B20 biodiesel blends. Similarly, the other emissions such as CO2, smoke and HC decrease about 5.38 %, 10.41 % and 5.38 % whereas the NOx formation increases about 7.67 % at peak loads due to a higher rate of combustion.