scholarly journals Experimental Validation of an Innovative Approach for GDI Spray Pattern Recognition

Fuels ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 16-36
Author(s):  
Federico Rosignoli ◽  
Lucio Postrioti
Keyword(s):  
Experimental Validation ◽  
Injection Pressure ◽  
Analysis Procedure ◽  
Operating Conditions ◽  
Innovative Approach ◽  
Diesel Sprays ◽  
Spray Structure ◽  
Counter Pressure ◽  
Pressure Injection ◽  
Triangle Method

In the present automotive scenario, along with hybridization, GDI technology is progressively spreading in order to improve the powertrain thermal efficiency. In order to properly match the fuel spray development with the combustion chamber design, using robust and accurate diagnostics is required. In particular, for the evaluation of the injection quality in terms of spray shape, vision tests are crucial for GDI injection systems. By vision tests, parameters such as spray tip penetration and cone angles can be measured, as the operating conditions in terms of mainly injection pressure, injection strategy, and chamber counter-pressure are varied. Provided that a complete experimental spray characterization requires the acquisition of several thousand spray images, an automated methodology for analyzing spray images objectively and automatically is mandatory. A decisive step in a spray image analysis procedure is binarization, i.e., the extraction of the spray structure from the background. Binarization is particularly challenging for GDI sprays, given their lower compactness with respect to diesel sprays. In the present paper, two of the most diffused automated binarization algorithms, namely the Otsu and Yen methods, are comparatively validated with an innovative approach derived from the Triangle method—the Last Minimum Criterion—for the analysis of high-pressure GDI sprays. GDI spray images acquired with three injection pressure levels (up to 600 bar) and two different optical setups (backlight and front illumination) were used to validate the considered algorithms in challenging conditions, obtaining encouraging results in terms of accuracy and robustness for the proposed approach.

Influence of Spray Velocity and Structure on the Air Entrainment in the Primary Breakup Zone of High Pressure Diesel Sprays

2002 ◽  
Author(s):  
Christian Schugger ◽  
Ulrich Renz
Keyword(s):  
High Pressure ◽  
Momentum Transfer ◽  
Scattered Light ◽  
Injection Pressure ◽  
Air Entrainment ◽  
Turbulent Dispersion ◽  
Nozzle Geometry ◽  
Diesel Sprays ◽  
Spray Structure ◽  
Primary Breakup

Nozzle geometry and rail pressure influence the gas-liquid momentum transfer and the turbulent dispersion in the primary breakup zone of high-pressure Diesel sprays, and consequently the combustion processes. To investigate these phenomena, different measuring techniques have been used. The spray structure is visualized using shadowgraphy and scattered light imaging, and the axial velocities in the dense spray region have been measured using a Laser Correlation Velocimeter. Gas velocities are measured using Particle Image Velocimetry. It is found that the dimensionless velocities (related to the frictionless velocity) are independent of the injection pressure and the nozzle geometry. However the momentum transfer between the liquid phase and the surrounding air strongly depends on the spray structure. Here a sharp edged nozzle inlet promotes cavitation and turbulence levels in the nozzle which leads to stronger breakup and significantly enhanced air entrainment.

Measurement of Biodiesel Blend and Conventional Diesel Spray Structure Using X-Ray Radiography

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
A. L. Kastengren ◽  
C. F. Powell ◽  
K.-S. Im ◽  
Y.-J. Wang ◽  
J. Wang
Keyword(s):  
Cone Angle ◽  
Injection Pressure ◽  
Fuel Distribution ◽  
X Ray ◽  
Spray Structure ◽  
Quantitative Measurements ◽  
Biodiesel Blend ◽  
Temporal And Spatial ◽  
Nozzle Geometries ◽  
Fuel Effects

The near-nozzle structure of several nonevaporating biodiesel-blend sprays has been studied using X-ray radiography. Radiography allows quantitative measurements of the fuel distribution in sprays to be made with high temporal and spatial resolution. Measurements have been made at different values of injection pressure, ambient density, and with two different nozzle geometries to understand the influences of these parameters on the spray structure of the biodiesel blend. These measurements have been compared with corresponding measurements of Viscor, a diesel calibration fluid, to demonstrate the fuel effects on the spray structure. Generally, the biodiesel-blend spray has a similar structure to the spray of Viscor. For the nonhydroground nozzle used in this study, the biodiesel-blend spray has a slightly slower penetration into the ambient gas than the Viscor spray. The cone angle of the biodiesel-blend spray is generally smaller than that of the Viscor spray, indicating that the biodiesel-blend spray is denser than the Viscor spray. For the hydroground nozzle, both fuels produce sprays with initially wide cone angles that transition to narrow sprays during the steady-state portion of the injection event. These variations in cone angle with time occur later for the biodiesel-blend spray than for the Viscor spray, indicating that the dynamics of the injector needle as it opens are somewhat different for the two fuels.

scholarly journals Effect of Valve Opening Manner and Sealing Method on the Steady Injection Characteristic of Gas Fuel Injector

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1479
Author(s):  
Tianbo Wang ◽  
Lanchun Zhang ◽  
Qian Chen
Keyword(s):  
Steady State ◽  
Three Dimensional ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Fuel Injector ◽  
Injection Efficiency ◽  
Mixing Performance ◽  
Cfd Models ◽  
Valve Opening ◽  
Gas Fuel

The steady-state injection characteristic of gas fuel injector is one of the key factors that affects the performance of gas fuel engine. The influences of different injection strategies, such as different injection angles and different injection positions, on the mixing performance in gas-fueled engine have been emphasized in previous literatures. However, the research on the injection characteristics of the gas fuel injector itself are insufficient. The three-dimensional steady-state computational fluid dynamics (CFD) models of two kinds of injectors, in different opening manners, and the other two kinds of injectors, in different sealing methods, were established in this paper. The core region speed, stagnation pressure loss and mass flow rate were compared. Additionally, the effective injection pressure (EIP) concept was also used to evaluate the injection efficiency of gas fuel injector. The simulation results show that the jet speed of the pull-open injector is higher than the push-open injector under the same operating conditions. The injection efficiency of the pull-open valve is about 56.0%, while the push-open valve is 50.3%. In general, the steady-flow characteristic of the pull-open injector is better than that of the push-open one. The injection efficiency of the flat sealing injector is 55.2%, slightly lower than the conical sealing method.

scholarly journals High Pressure Injection of Chemicals in a Gravel Beach

Processes ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 525
Author(s):  
Geng ◽  
Abdollahi-Nasab ◽  
An ◽  
Chen ◽  
Lee ◽  
...  
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
Lithium Bromide ◽  
Injection Pressure ◽  
Tidal Range ◽  
Application Of Surfactants ◽  
Pressure Injection ◽  
Oil Biodegradation ◽  
High Pressure Injection ◽  
Gravel Beach

The remediation of beaches contaminated with oil includes the application of surfactants and/or the application of amendments to enhance oil biodegradation (i.e., bioremediation). This study focused on evaluating the practicability of the high pressure injection (HPI) of dissolved chemicals into the subsurface of a lentic Alaskan beach subjected to a 5 m tidal range. A conservative tracer, lithium, in a lithium bromide (LiBr) solution, was injected into the beach at 1.0 m depth near the mid-tide line. The flow rate was varied between 1.0 and 1.5 L/min, and the resulting injection pressure varied between 3 m and 6 m of water. The concentration of the injected tracer was measured from four surrounding monitoring wells at multiple depths. The HPI associated with a flow rate of 1.5 L/min resulted in a Darcy flux in the cross-shore direction at 1.15 × 10−5 m/s compared to that of 7.5 × 10−6 m/s under normal conditions. The HPI, thus, enhanced the hydraulic conveyance of the beach. The results revealed that the tracer plume dispersed an area of ~12 m2 within 24 h. These results suggest that deep injection of solutions into a gravel beach is a viable approach for remediating beaches.

The Influence of Cylindrical Spray Chamber Geometry on the Evolution of High Pressure Diesel Sprays

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Dung Nguyen ◽  
Damon Honnery
Keyword(s):  
Threshold Value ◽  
Chamber Pressure ◽  
Spray Chamber ◽  
Combustion Chambers ◽  
Diesel Sprays ◽  
Spray Structure ◽  
Constant Volume Chamber ◽  
Illumination Method ◽  
Internal Chamber ◽  
Injection Pressures

While much is known on the effect of combustion chamber geometry on spray evolution in engines, less is known about its role in laboratory combustion chambers. This paper reports on a study, which investigates the effect of internal chamber geometry on the penetration and spreading angle of common rail nonreacting diesel sprays at room temperature conditions in a cylindrical constant volume chamber. This chamber has dimensions similar to those used in the literature. Spray chamber geometry was modified to yield three different chamber height-to-diameter ratios and two different nozzle stand-off distances. Sprays from three nozzles, two single-hole nozzles with different diameter and one twin-hole nozzle (THN), were examined for two injection pressures of 100 MPa and 150 MPa into two chamber pressures of 0.1 MPa and 5 MPa. To characterize the spray structure, a volume illumination method was used to study the spray tip penetration/speed and spread angle. For both injection pressures used with chamber pressure of 5 MPa, little sensitivity to vessel geometry was found in penetration distance and tip speed for variation in height to diameter ratio from 0.6 to 2.6 and variation in nozzle stand-off distance from 2 mm to 54 mm. For atmospheric chamber pressure, sensitivity to chamber geometry was evident and found to vary with nozzle type. Spread angle was found more largely affected by the calculation method and very sensitive to the image intensity threshold value for the cases investigated.

Effect of the Fuel Injection Strategy on Diesel Particulate Filter Regeneration in a Single-Cylinder Diesel Engine

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Sungjun Yoon ◽  
Hongsuk Kim ◽  
Daesik Kim ◽  
Sungwook Park
Keyword(s):  
Fuel Injection ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Particulate Filter ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Diesel Particulate ◽  
Injection Strategy ◽  
Dpf Regeneration ◽  
Exhaust Gas Temperature

Stringent emission regulations (e.g., Euro-6) have forced automotive manufacturers to equip a diesel particulate filter (DPF) on diesel cars. Generally, postinjection is used as a method to regenerate the DPF. However, it is known that postinjection deteriorates the specific fuel consumption and causes oil dilution for some operating conditions. Thus, an injection strategy for regeneration is one of the key technologies for diesel powertrains equipped with a DPF. This paper presents correlations between the fuel injection strategy and exhaust gas temperature for DPF regeneration. The experimental apparatus consists of a single-cylinder diesel engine, a DC dynamometer, an emission test bench, and an engine control system. In the present study, the postinjection timing was in the range of 40 deg aTDC to 110 deg aTDC and double postinjection was considered. In addition, the effects of the injection pressure were investigated. The engine load was varied among low load to midload conditions, and the amount of fuel of postinjection was increased up to 10 mg/stk. The oil dilution during the fuel injection and combustion processes was estimated by the diesel loss measured by comparing two global equivalences ratios: one measured from a lambda sensor installed at the exhaust port and one estimated from the intake air mass and injected fuel mass. In the present study, the differences of the global equivalence ratios were mainly caused by the oil dilution during postinjection. The experimental results of the present study suggest optimal engine operating conditions including the fuel injection strategy to obtain an appropriate exhaust gas temperature for DPF regeneration. The experimental results of the exhaust gas temperature distributions for various engine operating conditions are discussed. In addition, it was revealed that the amount of oil dilution was reduced by splitting the postinjection (i.e., double postinjection). The effects of the injection pressure on the exhaust gas temperature were dependent on the combustion phasing and injection strategies.

Fitness-for-Service and Remaining Useful Life Assessment of a Steam Drum

2003 ◽  
Author(s):  
Raymond K. Yee
Keyword(s):  
Power Plant ◽  
Small Sample ◽  
Analysis Procedure ◽  
Remaining Useful Life ◽  
Operating Conditions ◽  
Life Assessment ◽  
Life Evaluation ◽  
Useful Life ◽  
Size Evaluation ◽  
Steam Drum

A steam drum in a typical power plant has experienced in-service cracking. Nondestructive examinations (NDE) were performed and a small sample was collected from the drum to evaluate the extent of the cracking that had occurred in the drum shell. Fitness-for-service and remaining useful life analyses of the drum were performed based on the NDE results and operating conditions. In this paper, the fitness-for-service analyses of the steam drum are described. The analysis procedure, material property determination, stress analysis, limiting flaw size evaluation, and remaining useful life evaluation for the drum are discussed. Recommendations for appropriate action are also presented.

Ignition of Diesel Pilot Fuel in Dual-Fuel Engines

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Marcus Grochowina ◽  
Daniel Hertel ◽  
Simon Tartsch ◽  
Thomas Sattelmayer
Keyword(s):  
High Speed ◽  
Measurement Techniques ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Dual Fuel ◽  
Spray Formation ◽  
Fuel Concentration ◽  
Injection Parameters ◽  
Pilot Fuel ◽  
Ignition And Combustion

Dual-fuel (DF) engines offer great fuel flexibility combined with low emissions in gas mode. The main source of energy in this mode is provided by gaseous fuel, while the diesel fuel acts only as an ignition source. For this reason, the reliable autoignition of the pilot fuel is of utmost importance for combustion in DF engines. However, the autoignition of the pilot fuel suffers from low compression temperatures caused by Miller valve timings. These valve timings are applied to increase efficiency and reduce nitrogen oxide (NOx) emissions. Previous studies have investigated the influence of injection parameters and operating conditions on ignition and combustion in DF engines using a unique periodically chargeable combustion cell. Direct light high-speed images and pressure traces clearly revealed the effects of injection parameters and operating conditions on ignition and combustion. However, these measurement techniques are only capable of observing processes after ignition. In order to overcome this drawback, a high-speed shadowgraph technique was applied in this study to examine the processes prior to ignition. Measurements were conducted to investigate the influence of compression temperature and injection pressure on spray formation and ignition. Results showed that the autoignition of diesel pilot fuel strongly depends on the fuel concentration within the spray. The high-speed shadowgraph images revealed that in the case of very low fuel concentration within the pilot spray, only the first stage of the two-stage ignition occurs. This leads to large cycle-to-cycle variations and misfiring. However, it was found that a reduced number of injection holes counteract these effects. The comparison of a diesel injector with ten-holes and a modified injector with five-holes showed shorter ignition delays, more stable ignition and a higher number of ignited sprays on a percentage basis for the five-hole nozzle.

Effect of Fuel Injection Pressure and Engine Speed on Performance, Emissions, Combustion, and Particulate Investigations of Gasohols Fuelled Gasoline Direct Injection Engine

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Nikhil Sharma ◽  
Avinash Kumar Agarwal
Keyword(s):  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Driving Forces ◽  
Direct Injection ◽  
Engine Performance ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
Primary Alcohols ◽  
Renewable Fuel

Abstract Fuel availability, global warming, and energy security are the three main driving forces, which determine suitability and long-term implementation potential of a renewable fuel for internal combustion engines for a variety of applications. Comprehensive engine experiments were conducted in a single-cylinder gasoline direct injection (GDI) engine prototype having a compression ratio of 10.5, for gaining insights into application of mixtures of gasoline and primary alcohols. Performance, emissions, combustion, and particulate characteristics were determined at different engine speeds (1500, 2000, 2500, 3000 rpm), different fuel injection pressures (FIP: 40, 80, 120, 160 bars) and different test fuel blends namely 15% (v/v) butanol, ethanol, and methanol blended with gasoline, respectively (Bu15, E15, and M15) and baseline gasoline at a fixed (optimum) spark timing of 24 deg before top dead center (bTDC). For a majority of operating conditions, gasohols exhibited superior characteristics except minor engine performance penalty. Gasohols therefore emerged as serious candidate as a transitional renewable fuel for utilization in the existing GDI engines, without requirement of any major hardware changes.

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