Optimizing Thermal Efficiency and Emissions in Hybrid HCCI-DI Combustion with Biodiesel-Diethyl Ether-Nanoparticle Blends

Abstract

This study used a Homogeneous Charge Compression Ignition-Direct Injection (HCCI-DI) engine to test the combustion, performance, and emissions of neem oil biodiesel blends. Analysis of engine behaviour was conducted based on the biodiesel blending ratio, combustion mode, and addition of aluminium oxide (Al2O3) nano additive. It has been found that peak in-cylinder pressures (Pmax) and heat release rates decreased with increasing biodiesel content, both in Direct Injection (DI) and HCCI-DI. Compared to DI, the HCCI-DI improved combustion characteristics, while the nano Al2O3 provided further improvements. In DI and HCCI-DI, pure biodiesel reduced brake thermal efficiency (BTE) by 2.01% and 1.68%, respectively. However, diesel and biodiesel BTE increased when HCCI-DI was used, as well as Al2O3 nano additive. Nitrogen oxide (NOx) emissions from biodiesel increased by 18.3% in DI mode but decreased by 4.3% in HCCI-DI mode when nano additives were used. Hydrocarbon (HC) emissions are reduced by 52.17% by biodiesel, however they are increased by HCCI-DI mode. On the other hand, HC emissions are reduced by up to 19.51% by nano additives. Carbon monoxide (CO) emissions were reduced by up to 55.56%, and smoke emissions decreased by 22.7% in DI mode and 39.1% in HCCI-DI mode due to using biodiesel, HCCI-DI mode, and the nano additive. Combining biodiesel and HCCI-DI combustion in engines with Al2O3 nano additive enhances performance and reduces emissions.

Keywords

• neem oil biodiesel
• HCCI-DI combustion
• nano additive
• performance
• emissions

References

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