scholarly journals Simultaneous In-Cylinder Flow Measurement and Flame Imaging in a Realistic Operating Engine Environment Using High-Speed PIV

2019 ◽  
Vol 9 (13) ◽  
pp. 2678 ◽  
Author(s):  
Atsushi Nishiyama ◽  
Minh Khoi Le ◽  
Takashi Furui ◽  
Yuji Ikeda
Keyword(s):  
Flow Field ◽  
Flame Front ◽  
Flame Propagation ◽  
High Speed ◽  
Gasoline Engine ◽  
Fuel Injection ◽  
Front Propagation ◽  
Growth Direction ◽  
Flame Imaging ◽  
Cylinder Flow

Among multiple factors that affect the quality of combustion, the intricate and complex interaction between in-cylinder flow/turbulent field and flame propagation is one of the most important. In this study, true simultaneous, crank-angle resolved imaging of the flame front propagation and the measurement of flow-field was achieved by the application of high-speed Particle Image Velocimetry (PIV). The technique was successfully implemented to avoid problems commonly associated with PIV in a combustion environment, such as interferences and reflections, avoided thanks to a number of adjustments and arrangements. All experiments were carried out inside a single-cylinder optical gasoline engine operated at 1200 rpm, using port fuel injection (PFI) with stoichiometric mixtures. It was found that the global vortex location of the tumble motion heavily influences the flame growth direction as well as the flame shape, mainly due to the tumble-induced flow across the ignition source. The flame propagation also influences the flow-field such that the pre-ignition flow can be maintained and the flow of unburned region surrounding the flame front will be enhanced.

scholarly journals He misfire degree and its effects on combustion and pollutant formation of subsequent cycles: A study on a high speed gasoline engine

2021 ◽  
pp. 292-292
Author(s):  
Yangyang Chen ◽  
Qifei Jian ◽  
Banglin Deng ◽  
Kaihong Hou
Keyword(s):  
Flow Field ◽  
Flame Propagation ◽  
High Speed ◽  
Gasoline Engine ◽  
Working Process ◽  
No Emission ◽  
Pollutant Formation ◽  
Combustion Phase ◽  
Lower Temperature ◽  
Final Amount

Misfire has attracted lots of researcher?s attention as a common engine fault, but most researchers focus on misfire diagnosis. For motorcycle engines, misfire is more worth to investigate because of the more extensive operation windows. The misfire degree is detected by experiment and its effect mechanism on subsequent cycles is investigated through simulation. Its effect is analyzed through two aspects: 1) misfire cycle leaves about 10.8% fuels that participate in next cycle working process, leading to richer fuel/air mixture. But 13.8 % lower of in-cylinder peak pressure than normal scenario is observed. Then interaction between flame propagation and flow field is discussed. The effect of misfire on flow field intensity is small, but it changes flow field structure largely. This change evolves persistently during subsequent processes, superimposing the lower temperature brought by misfire of last cycle, resulting in slower flame propagation and thus lower thermal efficiency for misfire scenario. This impact can last 3-4 subsequent cycles until gradually fades away; 2) for pollutants formations, the NO emission is lower for misfire scenario due to the lower in-cylinder temperature, but HC emission is higher. Although higher CO is produced during main combustion phase for misfire scenario, it converts to CO2 more largely during post flame stage, resulting in almost the same final amount relative to normal scenario.

High Speed Fuel Injection System for 2-Stroke D.I. Gasoline Engine

1991 ◽  
Author(s):  
Michael M. Schechter ◽  
Eugene H. Jary ◽  
Michael B. Levin
Keyword(s):  
High Speed ◽  
Gasoline Engine ◽  
Fuel Injection ◽  
Injection System ◽  
Fuel Injection System

Classifying IC Engine Swirl Fields by Complex Moments

2019 ◽  
Author(s):  
Kwee-Yan Teh ◽  
Penghui Ge ◽  
Fengnian Zhao ◽  
David L. S. Hung
Keyword(s):  
Velocity Field ◽  
Flow Field ◽  
High Speed ◽  
Flow Fields ◽  
Flow Patterns ◽  
Analysis Approach ◽  
Flow Mode ◽  
Mean Velocity ◽  
Ic Engine ◽  
Cylinder Flow

Abstract Engine in-cylinder flow varies from cycle to cycle, which contributes to variation of the mixing and combustion processes between fuel and air. Such flow field cyclic variability at the macroscopic scale is distinct from random fluctuations at the microscopic scale about the ensemble mean velocity field due to turbulence. At the extreme, the mean velocity field may bear no resemblance to any instantaneous flow field within the ensemble. Rather, these instantaneous fields may appear multimodal. Yet previous attempts to define and identify the flow modes were either qualitative (by visual inspection), or based on strict point-by-point velocity difference between two flow fields. The former approach is clearly subjective; the latter does not accommodate translational and rotational variations of in-cylinder flow patterns relative to a flow mode. Such spatial variations, in location and orientation, of the flow patterns can be quantified by the technique of complex moment normalization. The algebraic properties of complex moments are also intimately related to the geometric and physical properties of two-dimensional/two-component flow fields. In this paper, we take the normalized moments as flow field attributes for further cluster analysis. This analysis approach is demonstrated using a set of in-cylinder flow fields obtained by high-speed particle image velocimetry on a swirl plane of a research optical engine operating under low intake swirl setting. The resulting classification of the flow fields into several clusters (flow modes) are discussed, and the potential and limitations of the analysis approach are appraised.

Flow and Mixture Distribution in a High-Speed Five-Valve Direct Injected Gasoline Engine

2006 ◽  
Vol 7 (2) ◽  
pp. 143-166 ◽  
Author(s):  
N Kampanis ◽  
C Arcoumanis ◽  
S Kometani ◽  
R Kato ◽  
H Kinoshita
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Gasoline Engine ◽  
Flow Instability ◽  
Direct Injection ◽  
Mixture Distribution ◽  
Direct Injection Engines ◽  
Planar Laser ◽  
Performance And Emissions ◽  
Cylinder Flow

The in-cylinder flow, spray dynamics, air-spray interaction, and fuel vapour distribution have been characterized in a motorcycle five-valve gasoline engine in terms of their effect on performance and emissions. A five-valve single-cylinder optical engine was employed which operated at speeds up to 3000 r/min in the close spacing configuration, with an early induction injection strategy using a centrally mounted swirl pressure atomizer. Particle image velocimetry, spray imaging in a spray chamber and in the engine, and planar laser-induced fluorescence revealed the importance of a strong and ordered in-cylinder flow for the efficient distribution of the liquid fuel throughout the cylinder volume and its complete evaporation prior to combustion, especially in the relatively low speed regime investigated. Furthermore, in the absence of a large-scale vortex structure during compression, incomplete mixing may still occur, resulting in mixture inhomogeneities and flow instability. Consequently, in contrast to port fuel injected engines, where good mixing could be achieved at high revolution rates, even with an unstructured flow, in direct injection engines an ordered flow structure is a prerequisite for efficient combustion and low exhaust emissions.

Research on Signal Simulator at Crankshaft of Motorcycle Gasoline Engine

2012 ◽  
Vol 614-615 ◽  
pp. 414-421
Author(s):  
Chang Sheng Wang ◽  
Tie Zao Yang ◽  
Haijun Zhang ◽  
Hong Jie Zhao
Keyword(s):  
Control System ◽  
Pulse Width ◽  
High Speed ◽  
Gasoline Engine ◽  
Fuel Injection ◽  
Position Sensor ◽  
Operational Environment ◽  
Development Platform ◽  
Injection Pulse ◽  
Motorcycle Engine

Cam signals, crankshaft signals and angle signals were simulated by analogue crankshaft position sensors developed by C8051F series micro processors to emulate the operational environment of motorcycle engine. In the software development platform of gasoline engine, software running status of control system was tested. MP424 high-speed sampling card was applied to actually observe properties of ignition advance angle and fuel injection advance angle. The experiment suggested that practically observed fuel injection pulse width, ignition pulse width, properties of ignition advance angle and fuel injection advance angle were the same as those of models of control system software. This proved that the analogue crankshaft position sensor that has been developed is practical and feasible.

Experimental Study of Flame Stretch Under Engine-Like Conditions

2017 ◽  
Author(s):  
Behdad Afkhami ◽  
Yanyu Wang ◽  
Scott A. Miers ◽  
Jeffrey D. Naber
Keyword(s):  
Flame Front ◽  
Flame Propagation ◽  
High Speed ◽  
Combustion Engine ◽  
Turbulent Flame ◽  
Experimental Studies ◽  
Flame Velocity ◽  
Turbulent Flame Speed ◽  
Stretch Rate ◽  
Flame Stretch

Since fossil fuels will remain the main source of energy for power generation and transportation in next decades, their combustion processes remain an important concern for the foreseeable future. For liquid or gaseous fuels, flame velocity that propagates normal to itself and relative to the flow into the unburned mixture is one of the most important quantities to study. In a non-uniform flow, a curved flame front area changes continually which is known as flame stretch. The concept becomes more important when it is realized that the stretch affects the turbulent flame speed. The current research empirically studies flame stretch under engine-like conditions since there has not been enough experimental studies in this area. For this reason, a one-cylinder, direct-injection, spark-ignition, naturally-aspirated optical engine was utilized to image the flame propagation process inside an internal combustion engine cylinder on the tumble plane. The flame front was found by processing high speed images which were taken from the flame inside the cylinder. Flame front propagation analysis showed that after the flame kernel was developed, during flame propagation period, the stretch rate decreased until the flame front touches the piston surface. This trend was common among stoichiometric, lean, and rich mixtures. In addition, the fuel-air mixture with λ = 0.85 showed lower stretch rate compared to stoichiometric or lean mixture with λ = 1.2. However, based on previous studies, further enrichment may result in the flame stretch rate become greater than that of the stretch rates for stoichiometric or lean mixtures. Also, comparing the stretch rate at two different engine speeds revealed that as the speed increased the stretch rate also increased; especially during the early flame development period. Therefore, according to previous studies which discussed flame stretch as a mechanism for flame extinguishment, the probability of the flame extinction is higher when the engine speed is higher.

Visualization of Different Flashback Mechanisms for H2/CH4 Mixtures in a Variable-Swirl Burner

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Parisa Sayad ◽  
Alessandro Schönborn ◽  
Mao Li ◽  
Jens Klingmann
Keyword(s):  
Flow Field ◽  
Flame Propagation ◽  
Mass Flow ◽  
High Speed ◽  
Vortex Breakdown ◽  
Propagation Speed ◽  
Swirl Burner ◽  
Air Mass ◽  
Auto Ignition ◽  
Fuel Mixtures

Flame flashback from the combustion chamber to the premixing section is a major operability issue when using high H2 content fuels in lean premixed combustors. Depending on the flow-field in the combustor, flashback can be triggered by different mechanisms. In this work, three flashback mechanisms of H2/CH4 mixtures were visualized in an atmospheric variable-swirl burner using high speed OH* chemiluminescence imaging. The H2 mole fraction of the tested fuel mixtures varied between 0.1 and 0.9. The flow-field in the combustor was varied by changing the swirl number from 0.0 to 0.66 and the total air mass-flow rate from 75 to 200 SLPM (standard liters per minute). The following three types of flashback mechanism were observed: Flashback caused by combustion induced vortex breakdown (CIVB) occurred at swirl numbers ≥0.53 for all of the tested fuel mixtures. Flashback in the boundary layer (BL) and flame propagation in the premixing tube caused by auto-ignition were observed at low swirl numbers and low total air mass-flow rates. The temporal and spatial propagation of the flame in the optical section of the premixing tube during flashback was studied and flashback speed for different mechanisms was estimated. The flame propagation speed during flashback was significantly different for the different mechanisms.

Sign in / Sign up

Export Citation Format

Share Document