scholarly journals Controlled autoignition of hydrogen in a direct-injection optical engine

2012 ◽  
Vol 159 (7) ◽  
pp. 2500-2515 ◽  
Author(s):  
Pavlos G. Aleiferis ◽  
Martino F. Rosati
Keyword(s):  
Direct Injection ◽  
Optical Engine ◽  
Controlled Autoignition

Flame Emission Characteristics in a Direct Injection Spark Ignition Optical Engine Using Image Processing Based Diagnostics

2018 ◽  
Author(s):  
Zhe Sun ◽  
Zhen Ma ◽  
Xuesong Li ◽  
Min Xu
Keyword(s):  
Image Processing ◽  
Diffusion Flame ◽  
Internal Combustion Engines ◽  
Imaging System ◽  
Direct Injection ◽  
Spark Ignition ◽  
Spectral Correlation ◽  
Optical Engine ◽  
Flame Emission ◽  
Direct Injection Spark Ignition

Non-intrusive measurements are always desirable in flame research, particularly in the study of internal combustion engines where intrusive measurements are usually not applicable. With the use of digital image processing and color analysis, the imaging system can be turned into an abstract multi-spectral system to determine the characteristics of flame emission. First this study conducts a precise calibration to make up a spectral correlation between the camera spectrum responses and the radical emissions of an ethanol diffusion flame. The color model of HSV is used to represent the camera spectrum responses. The actual wavelength of each radical of the diffusion flame has also been examined using a spectrograph. Subsequent experiment is the application of the spectral correlation into a direct injection spark ignition optical engine to research the combustion behavior. Two fuel injectors, different in nozzle configuration, were utilized and tested individually. The high-speed imaging system films hundreds of engine combustion cycles, and each cycle covers the propagation from the flame ignition stage towards the end of combustion. In those cycles, the presence of radicals of interest was captured and represented by Hue degree.

Combustion Characteristics of Methane Direct Injection Engine Under Various Injection Timings and Injection Pressures

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Jingeun Song ◽  
Mingi Choi ◽  
Daesik Kim ◽  
Sungwook Park
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Injection Pressure ◽  
Combustion Characteristics ◽  
Direct Injection Engine ◽  
Optical Engine ◽  
Start Of Injection ◽  
Crank Angle ◽  
Combustion Speed ◽  
Injection Pressures

The performance of a methane direct injection engine was investigated under various fuel injection timings and injection pressures. A single-cylinder optical engine was used to acquire in-cylinder pressure data and flame images. An outward-opening injector was installed at the center of the cylinder head. Experimental results showed that the combustion characteristics were strongly influenced by the end of injection (EOI) timing rather than the start of injection (SOI) timing. Late injection enhanced the combustion speed because the short duration between the end of injection and the spark-induced strong turbulence. The flame propagation speeds under various injection timings were directly compared using crank-angle-resolved sequential flame images. The injection pressure was not an important factor in the combustion; the three injection pressure cases of 0.5, 0.8, and 1.1 MPa yielded similar combustion trends. In the cases of late injection, the injection timings of which were near the intake valve closing (IVC) timing, the volumetric efficiency was higher (by 4%) than in the earlier injection cases. This result implies that the methane direct injection engine can achieve higher torque by means of the late injection strategy.

Early Direct-Injection, Low-Temperature Combustion of Diesel Fuel in an Optical Engine Utilizing a 15-Hole, Dual-Row, Narrow-Included-Angle Nozzle

2008 ◽  
Vol 1 (1) ◽  
pp. 1057-1082 ◽  
Author(s):  
Glen C. Martin ◽  
Charles J. Mueller ◽  
David M. Milam ◽  
Michael S. Radovanovic ◽  
Christopher R. Gehrke
Keyword(s):  
Low Temperature ◽  
Diesel Fuel ◽  
Direct Injection ◽  
Low Temperature Combustion ◽  
Included Angle ◽  
Optical Engine ◽  
Temperature Combustion

3D Numerical Simulation of Stratified Mixture Formation of DI LPG Engine

2013 ◽  
Vol 328 ◽  
pp. 975-980
Author(s):  
Juan Xu ◽  
Zhong Hai Zhou ◽  
Zong Rui Hao ◽  
Bo Yan Xu
Keyword(s):  
Formation Process ◽  
Direct Injection ◽  
Low Carbon ◽  
Power Performance ◽  
Mixture Formation ◽  
Low Carbon Economy ◽  
Rich Mixture ◽  
Optical Engine ◽  
The Rich ◽  
Carbon Economy

Low-carbon economy is a necessary requirement for sustainable development. LPG Direct Injection (DI) method can greatly improve the engines power performance, fuel economy and emission characteristics, hence a new wall-guided combustion system with a specially designed piston cavity used to form lean stratified mixture for DI LPG engine was proposed. In this paper, the stratified mixture formation process of a DI LPG engine was simulated. Before this, the model and method used in the simulation was firstly validated by simulating mixture formation process in an optical engine with conventional piston. The simulation results of the stratified mixture formation showed that, the mixture could gradually move upward along the combustion chamber wall under the guide of the spray induced entrainment vortex and the wall. At the same time, the rich mixture would diffuse to its surroundings. Finally, by the time to ignition, the ignitable stratified lean mixture could be formed.

A wall-adapted zonal URANS/LES methodology for the scale-resolving simulation of engine flows

2021 ◽  
pp. 146808742110323
Author(s):  
Clara Iacovano ◽  
Alessandro d’Adamo ◽  
Stefano Fontanesi ◽  
Giovanni Di Ilio ◽  
Vesselin Krassimirov Krastev
Keyword(s):  
Turbulence Modeling ◽  
Direct Injection ◽  
Thermal Power ◽  
Specific Flow ◽  
Direct Injection Engines ◽  
Optical Engine ◽  
Cycle Simulation ◽  
Flow Features ◽  
Mesh Resolution ◽  
Near Wall

In the present paper, a comprehensive, wall-adapted zonal URANS/LES methodology is shown for the multidimensional simulation of modern direct-injection engines. This work is the latest update of a zonal hybrid turbulence modeling approach, specifically developed by the authors for a flexible description of in-cylinder turbulent flow features with an optimal balance between computational costs and accuracy. Compared to the previous developments, a specific near-wall treatment is added, in order to preserve full-URANS behavior in the first near-wall cells, having in mind typically available mesh resolution in this part of the fluid domain. The updated methodology is applied to the multi-cycle simulation of a reference single-cylinder optical engine, which features a twin-cam, overhead-valve pent-roof cylinder head, and is representative of the current generation of spark-ignited direct-injection thermal power units. Results based on phase-specific flow field statistics and synthetic quality indices demonstrate the consistency and effectiveness of the proposed methodology, which is then qualified as a suitable candidate for affordable scale-resolving analyses of cycle to cycle variability (CCV) phenomena in direct-injection engines.

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