Comparative study of exhaust gas recirculation (EGR) and hydrogen-enriched EGR employed in a SI engine fueled by biobutanol-gasoline. (15th May 2020)

• Record Type: Journal Article
• Authors: Zhao, Lifeng; Su, Xiangyang; Wang, Xueyuan
• Is Part Of: Fuel. Volume 268(2020)
• Publication Date: 2020-05-15
• Subjects: Engine -- EGR -- Hydrogen -- Butanol -- PM -- Emissions; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2020.117194
• Languages: English
• ISSNs: 0016-2361

Abstract

Abstract: In this study, hydrogen was added to a isobutanol-gasoline engine during exhaust gas recirculation (EGR) operation. The effects of combined hydrogen-enrichment and EGR (HEGR) were assessed in terms of improvements in engine thermal efficiency and emissions reduction. The results showed that hydrogen had a positive influence on the combustion behaviors of butanol-gasoline during EGR operation, as well as markedly reduced ignition delay and rapid burning duration, which was prolonged significantly when EGR operated alone. There was a higher brake thermal efficiency (BTE) for the butanol-gasoline engine during HEGR, which enhanced the BTE up ~3–4%. Combustion stability was improved while the tendency for slowed burning with EGR was suppressed with hydrogen addition. Wider EGR limits with hydrogen addition was observed due to improved combustion stability. During EGR operation, there were increased unburnt hydrocarbon emissions in butanol-gasoline engine, which was significantly reduced with hydrogen addition. Low NOx emissions were observed during HEGR operation at the high EGR rate, which exhibited effective inhibition regarding particle number emissions including particles in the nucleation and accumulation modes. HEGR was more effective in reducing PM compared to EGR. The particle surface area concentration was significantly reduced with HEGR operation, and the particle size was slightly reduced.