Effect of fuel composition and EGR on spark-ignited engine combustion with LPG fueling: Experimental and numerical investigation. (1st November 2022)

• Record Type: Journal Article
• Authors: Kar, Tanmay; Fosudo, Toluwalase; Marchese, Anthony; Windom, Bret; Olsen, Daniel
• Is Part Of: Fuel. Volume 327(2022)
• Publication Date: 2022-11-01
• Subjects: Liquefied petroleum gas -- Knock -- Exhaust gas recirculation -- Ignition delay -- Livengood-Wu integral -- CFD; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2022.125221
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: This paper presented the effect of LPG fuel composition and EGR on SI engine combustion characteristics. Both experimental and numerical investigations were performed with three LPG fuels and EGR at different compression ratios. All the tested fuels transitioned from normal to knocking combustion with the increase of compression ratio, with a more substantial impact for the fuel with high reactivity. A zonal-based kinetic interactions study demonstrated the knock mitigation effectiveness of EGR over the pressure–temperature domain relevant to SI engine operation. Finally, the multidimensional CFD simulations presented the evolution of in-cylinder temperature and chemical species, demonstrating the development of end-gas autoignition events without and with EGR for LPG fueling. Abstract: This paper presents an experimental and numerical investigation of a spark-ignited (SI) cooperative fuel research (CFR) engine fueled with different liquefied petroleum gas (LPG) fuels and exhaust gas recirculation (EGR). The effects of LPG fuel composition on engine combustion characteristics are initially evaluated at two different compression ratios (CR). Results show normal combustion at CR 7 and heavy knocking combustion at CR 10 for all the tested fuels, with a more substantial impact for the LPG fuel with high proportions of n-butane species. The Livengood-Wu (LW) integral method is then used to analyze the knock occurrence risk of individual fuel based on the reactivity of the tested fuels. The introduction of EGR then demonstrates the potential of knock intensity reduction below the borderline knock limit. A zonal-based kinetic interactions study is also performed to understand the knock mitigation effectiveness of EGR over the pressure–temperature domain relevant to SI engine operation. Finally, a multidimensional, computational fluid dynamics (CFD) simulation model is shown to predict the LPG combustion characteristics and presents the evolution of in-cylinder temperature and chemical species to demonstrate the development of end-gas autoignition events without and with EGR.