Title: Study of in-cylinder mixing performance of gas-fuel engine under PFI-DI hybrid injection condition

Authors: Tianbo Wang; Yu Wang; Jing Chen; Lanchun Zhang; Li Li; Yanyun Sun

Addresses: Department of Automotive Transportation and Engineering, Jiangsu University of Technology, Changzhou, Jiangsu Province, China ' Department of Automotive Transportation and Engineering, Jiangsu University of Technology, Changzhou, Jiangsu Province, China ' Department of Automotive Transportation and Engineering, Jiangsu University of Technology, Changzhou, Jiangsu Province, China ' Department of Automotive Transportation and Engineering, Jiangsu University of Technology, Changzhou, Jiangsu Province, China ' Department of Automotive Transportation and Engineering, Jiangsu University of Technology, Changzhou, Jiangsu Province, China ' Department of Automotive Transportation and Engineering, Jiangsu University of Technology, Changzhou, Jiangsu Province, China

Abstract: To further explore the possibility of integrating port fuel injection (PFI) and direct injection (DI) to enhance the in-cylinder mixing performance in natural gas engines, a computational fluid dynamics (CFD) model of PFI-DI hybrid injection was developed to analyse the effects of PFI/DI supply ratio on methane mixing uniformity. The results indicate that the best mixing performance is achieved under the PFI method, with a high percentage of 56.13% for the best methane concentration region (BMCR) at ignition. When the PFI/DI supply ratio is 70/30, the BMCR percentage at ignition is the highest compared to other hybrid injection scenarios, and the methane distribution is more favourable to flame propagation than 100% direct injection. When the PFI/DI supply ratio stands at 65/35 or below, the BMCR percentage at ignition tends to stabilise, influenced by in-cylinder flow velocity, turbulent kinetic energy, and concentration differentials. [Received: December 4, 2023; Accepted: May 29, 2024]

Keywords: port fuel injection; PFI; direct injection; DI; mixing performance; natural gas engine; hybrid injection.

DOI: 10.1504/IJOGCT.2025.145443

International Journal of Oil, Gas and Coal Technology, 2025 Vol.37 No.3, pp.362 - 379

Received: 01 Dec 2023
Accepted: 29 May 2024
Published online: 01 Apr 2025 *

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