Numerical Investigations of Injection Timing Effects on a GDI Engine Performance: Part B, In-Cylinder Emission Formation and Oxidation Process

Yu Zhang,Jiahong Fu,Ruijie Li,Ruomiao Yang,Yuchao Yan,Zhentao Liu

doi:10.3389/fenrg.2022.823386

Abstract

The emphasis on environmental protection and energy security has promoted automobile engine technology toward low emission and economy. While the traditional port fuel injection engine can hardly meet the latest regulations and requirements, the gasoline direct injection (GDI) engine becomes a hot research topic because of its potential to reduce fuel consumption and emissions. Since injection timing has a determining effect on overall engine performance, this paper aimed to investigate the injection timing effects on mixture formation and emissions. A validated three-dimensional numerical simulation model of a 4-stroke GDI engine combustion chamber was adopted. In a previous work (Part A), the in-cylinder combustion process has been discussed. In this study, the simulation results demonstrate that with the injection timing advancing, the fuel–gas mixture was more uniformly distributed and combusted more completely; the CO, UHC, and soot had decreased sharply by 80.6, 99.2, and 97.5%; the NOx emission increased by 151.7%. The optimized injection timing for this case was 300 CA BTDC. Moreover, this paper studied the in-cylinder views of injection timing effects on mixture formation and emission, providing reference to optimize injection of GDI engine.

Highlights

The increasing prominent energy shortage and emission pollution have put forward severe challenges to the automobile power system (Gasbarro et al, 2019; Yang et al, 2021)
While the traditional port fuel injection (PFI) engine has difficulty meeting the requirement of environment protection and economic efficiency, attention is attracted to the gasoline direct injection (GDI) engine (Wang and Shuai, 2011; Liu and Wang, 2022)
The results showed that flash boiling injection resulted in lower apparent flame velocity and flame area compared with supercooled injection, which was due to the supercooled combustion conditions

Summary

Introduction

The increasing prominent energy shortage and emission pollution have put forward severe challenges to the automobile power system (Gasbarro et al, 2019; Yang et al, 2021). Reducing emissions and improving the efficiency of internal combustion engines (ICEs) have become the main targets of research on vehicle engines (Ambrogi et al, 2019; Duronio et al, 2020). Many researchers have studied combustion models (Keskinen et al, 2016; Shi et al, 2019), heat transfer (Hongliang et al, 2016; Xu et al, 2020a), injection strategies (Shi et al, 2018; Chai et al, 2021), and emissions (Liu and Rigopoulos, 2019; Lin et al, 2021) related to internal combustion engines. Considering the significant improvement in thermal efficiency and reducing fuel cost, the GDI engine has become a hot research topic (Leduc et al, 2003; Han et al, 2020)

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Results

Conclusion