The combustion, performance and emissions investigation of a dual-fuel diesel engine using silicon dioxide nanoparticle additives to methanol

Highlights: • Nano-SiO₂ addition increases HRRmax and Pmax, especially at high engine load. • SiO₂ nanoparticles cause obvious ignition and combustion duration improvements. • Nano-SiO₂ additives in methanol increase BTE and lessen BSFC. • SiO₂ nanoparticles suppress significantly CO, HC, NO_X and smoke emissions. The study made investigation on the combustion, performance and emissions of a modern dual fuel (DF) diesel engine using silicon dioxide (SiO₂) nanoparticle additives to methanol under different test conditions. The tests were conducted in three operating modes: diesel mode; methanol/diesel mode (methanol mode for short) and methanol-based SiO₂ nanofluid (MSN)/diesel mode (MSN mode for short) where the MSN was injected in the intake manifold. The results displayed that nano-SiO₂ inclusion in methanol increased the peak pressure by 8.6% in maximum and peak heat release rate by 4.3% in maximum. The brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) were improved with all the tested dosages of SiO₂ nanoparticles in the fuel, especially under high load conditions, the improvements of 5.1% in maximum and 6.2% in maximum for BTE and BSFC were achieved. Compared with the cases in methanol mode, CO, HC, NO_x and smoke opacity in MSN mode were reduced by 38.5%, 55.4%, 5.2% and 55.6%, respectively. All the results indicate that the addition of SiO₂ nanoparticle in methanol could enhance the combustion and performance characteristics, and suppress the emissions of the DF diesel engines.