Sustainable emission reduction in diesel engines using hybrid nanocatalyst and producer gas‐assisted soapstock biodiesel

The integration of waste biodiesel, metal oxide nanocatalysts, and gaseous dual‐fuel combustion enhances compression ignition (CI) engine performance and reduces emissions. This investigation has been carried out on soapstock biodiesel (SB) produced from soapstock (waste material of vegetable oil processing), enhanced with a hybrid nanocatalyst of graphene oxide (GO) with titanium dioxide (TiO 2 ) nanoparticles at 50 parts per million (ppm). Producer gas (PG), a fuel gas mixture produced through biomass gasification, is also used to facilitate combustion at 4 and 8 lpm in a CI engine. The nano‐enabled fuel blend, B50 (50 SB + 50 D) containing GO/TiO 2 at 50 ppm augmented with PG at 8 lpm also showed superior combustion, performance and emission results. Maximum cylinder pressure increased by 5.6% over diesel, while the heat release rate (HRR) rose by 9.75%, indicating enhanced combustion. The brake thermal efficiency (BTE), representing the capacity of utilizing the fuel energy to produce the mechanical work in the engine, increased by 6.45% and the brake specific energy consumption (BSEC), which is the energy consumption per unit brake power, decreased by 2.73%, indicating better fuel utilization. The analysis of emissions revealed decreases of 41.7% in carbon monoxide (CO), 29.8% in hydrocarbons (HC), and 20.9% in smoke opacity (the amount of soot in the exhaust). Nitrogen oxide (NOx) emission was reduced by 6.67% with the nano‐assisted dual‐fuel operation. Results indicate that integrating nanocatalysts and producer gas with waste‐based biodiesel enhances CI engine performance, reduces emissions, and improves sustainability.