Gasoline direct injection(GDI)engines are currently the dominant powertrains for passenger cars.With the implementation of increasingly stringent fuel consumption and emission regulationsworldwide,GDI engines are faci...Gasoline direct injection(GDI)engines are currently the dominant powertrains for passenger cars.With the implementation of increasingly stringent fuel consumption and emission regulationsworldwide,GDI engines are facing challenges owing to high particulate matter emissions and a tendency to knock,leading to a change in the research and design(R&D)issues compared with those in the twentieth century.This paper reviews the progress in research regarding GDI engine technologies over the past 20 years,focusing on combustion system configurations,and also highlights common issues in GDI R&D,including pre-ignition and deto-knock,soot formation and PM emissions,injector deposits and gasoline compression ignition(GCI).First,an overview of recent developments in the field as driven by regulations is provided,following which progress in injection and combustion systems is examined.Third,the review addresses the occurrence and mechanism of deto-knock and considers means of suppressing this phenomenon.The fourth section discusses soot formation mechanisms and particulate matter emission characteristics of GDI engines and describes the application of gasoline particulate filter(GPF)after-treatment.The subsequent section summarizes studies regarding injector deposit formation,as well as pioneering research into GCI combustion modes.Finally,a summary and future prospects for GDI engine technologies are provided.展开更多
Plasma ignition technology has delivered good performance in the aerospace industry. In this study, a pre-combustion plasma jet igniter was designed, and its characteristics were examined from three aspects: the morph...Plasma ignition technology has delivered good performance in the aerospace industry. In this study, a pre-combustion plasma jet igniter was designed, and its characteristics were examined from three aspects: the morphology, temperature, and discharge characteristics and process of ignition. Images of the OH distribution were obtained by using an OH Planar Laser-Induced Fluorescence(OH-PLIF) experimental system. Results have shown that the proposed plasma jet had a higher OH concentration, longer length, and larger area than those of a traditional igniter. The stability of discharge of the igniter was improved as the equivalence ratio φ was increased, and reducing gas flow reduced the pulsation of the plasma jet. When the input current was increased from 15A to 35 A, the highest average temperature increased from 5127 K to 7987 K. An increase in the equivalence ratio reduced the region of arc ionization, but expanded the regions of the core combustion reaction and the outer flame. Herein, this study has obtained a deep understanding of the jet and ignition law and developed a new idea for the application of plasma in the ignition field.A pre-combustion plasma jet igniter can significantly improve the efficiency of ignition and shorten the ignition process compared with a traditional igniter.展开更多
基金The authors acknowledge theChina NationalNat-ural Science Foundation Project“Formation and Evolution of PM from GDI Engines:From Primary Particles to Secondary Aerosols”(Grant No.51636003)the National Key R&D Plan Project“Integration Technology of PM Capture and Clean Emissions for GDI Vehicles”(Grant No.2017YFC02110004).
文摘Gasoline direct injection(GDI)engines are currently the dominant powertrains for passenger cars.With the implementation of increasingly stringent fuel consumption and emission regulationsworldwide,GDI engines are facing challenges owing to high particulate matter emissions and a tendency to knock,leading to a change in the research and design(R&D)issues compared with those in the twentieth century.This paper reviews the progress in research regarding GDI engine technologies over the past 20 years,focusing on combustion system configurations,and also highlights common issues in GDI R&D,including pre-ignition and deto-knock,soot formation and PM emissions,injector deposits and gasoline compression ignition(GCI).First,an overview of recent developments in the field as driven by regulations is provided,following which progress in injection and combustion systems is examined.Third,the review addresses the occurrence and mechanism of deto-knock and considers means of suppressing this phenomenon.The fourth section discusses soot formation mechanisms and particulate matter emission characteristics of GDI engines and describes the application of gasoline particulate filter(GPF)after-treatment.The subsequent section summarizes studies regarding injector deposit formation,as well as pioneering research into GCI combustion modes.Finally,a summary and future prospects for GDI engine technologies are provided.
基金co-supported by the National Natural Science Foundation of China(No.52306123)the Postdoctoral Science Foundation,China(No.2023M734277)the Natural Science Basic Research Program of Shaanxi,China(No.2021JQ-046)。
文摘Plasma ignition technology has delivered good performance in the aerospace industry. In this study, a pre-combustion plasma jet igniter was designed, and its characteristics were examined from three aspects: the morphology, temperature, and discharge characteristics and process of ignition. Images of the OH distribution were obtained by using an OH Planar Laser-Induced Fluorescence(OH-PLIF) experimental system. Results have shown that the proposed plasma jet had a higher OH concentration, longer length, and larger area than those of a traditional igniter. The stability of discharge of the igniter was improved as the equivalence ratio φ was increased, and reducing gas flow reduced the pulsation of the plasma jet. When the input current was increased from 15A to 35 A, the highest average temperature increased from 5127 K to 7987 K. An increase in the equivalence ratio reduced the region of arc ionization, but expanded the regions of the core combustion reaction and the outer flame. Herein, this study has obtained a deep understanding of the jet and ignition law and developed a new idea for the application of plasma in the ignition field.A pre-combustion plasma jet igniter can significantly improve the efficiency of ignition and shorten the ignition process compared with a traditional igniter.
