Refine Your Search

Search Results

Viewing 1 to 7 of 7
Technical Paper

Spark Mechanism in High Speed Flow

2019-04-02
2019-01-0729
An experimental study was performed to investigate spark ignition and subsequent spark stretch evolution in an inert environment at high- flow velocities up to 32 m/s across the spark plug gap in a constant-volume optical combustion-vessel at pressures representative of those in an engine. The vessel is capable of generating various in-cylinder thermodynamic conditions representative of light-duty spark ignition engines. The characteristic behavior of the spark was investigated using both a high-speed optical diagnostics and electrical measurement. Charge gas pressures were varied from 15 to 45 bar. Results show that the spark, flowing downstream the spark plug, is subject to short circuits of the spark channel and/or restrikes. The frequency of the restrike increased with increased flow velocity and charge gas pressure and decreased discharge current level.
Journal Article

An Experimental and Numerical Study of Diesel Spray Impingement on a Flat Plate

2017-03-28
2017-01-0854
Combustion systems with advanced injection strategies have been extensively studied, but there still exists a significant fundamental knowledge gap on fuel spray interactions with the piston surface and chamber walls. This paper is meant to provide detailed data on spray-wall impingement physics and support the spray-wall model development. The experimental work of spray-wall impingement with non-vaporizing spray characterization, was carried out in a high pressure-temperature constant-volume combustion vessel. The simultaneous Mie scattering of liquid spray and schlieren of liquid and vapor spray were carried out. Diesel fuel was injected at a pressure of 1500 bar into ambient gas at a density of 22.8 kg/m3 with isothermal conditions (fuel, ambient, and plate temperatures of 423 K). A Lagrangian-Eulerian modeling approach was employed to characterize the spray-gas and spray-wall interactions in the CONVERGETM framework by means of a Reynolds-Averaged Navier-Stokes (RANS) formulation.
Journal Article

Comparison of Direct-Injection Spray Development of E10 Gasoline to a Single and Multi-Component E10 Gasoline Surrogate

2017-03-28
2017-01-0833
Optical and laser diagnostics enable in-depth spray characterization in regards to macroscopic spray characteristics and in-situ fuel mixture quality information, which are needed in understanding the spray injection process and for spray model development, validation and calibration. Use of fuel surrogates in spray researches is beneficial in controlling fuel parameters, developing spray and combustion kinetic models, and performing laser diagnostics with known fluorescence characteristics. This study quantifies and evaluates the macroscopic spray characteristics of a single and multi-component surrogate in comparison to a gasoline with 10% ethanol under gasoline direct injection (GDI) engine conditions. In addition, the effect of fuel tracers on spray evolution and vaporization is also investigated. Both diethyl-methyl-amine/fluorobenzene as a laser-induced exciplex (LIEF) fluorescence tracer pair and 3-pentanone as a laser-induced fluorescence (LIF) tracer are examined.
Technical Paper

Process for Study of Micro-pilot Diesel-NG Dual Fuel Combustion in a Constant Volume Combustion Vessel Utilizing the Premixed Pre-burn Procedure

2019-04-02
2019-01-1160
A constant volume spray and combustion vessel utilizing the pre-burn mixture procedure to generate pressure, temperature, and composition characteristic of near top dead center (TDC) conditions in compression ignition (CI) engines was modified with post pre-burn gas induction to incorporate premixed methane gas prior to diesel injection to simulate processes in dual fuel engines. Two variants of the methane induction system were developed and studied. The first used a high-flow modified direct injection injector and the second utilized auxiliary ports in the vessel that are used for normal intake and exhaust events. Flow, mixing, and limitations of the induction systems were studied. As a result of this study, the high-flow modified direct injection injector was selected because of its controlled actuation and rapid closure. Further studies of the induction system post pre-burn were conducted to determine the temperature limit of the methane auto-ignition.
Technical Paper

Investigation of the Impact of Impingement Distance on Momentum Flux Rate of Injection Measurements of a Diesel Injector

2015-04-14
2015-01-0933
Diesel combustion and emissions is largely spray and mixing controlled. Spray and combustion models enable characterization over a range of conditions to understand optimum combustion strategies. The validity of models depends on the inputs, including the rate of injection profile of the injector. One method to measure the rate of injection is to measure the momentum, where the injected fuel spray is directed onto a force transducer which provides measurements of momentum flux. From this the mass flow rate is calculated. In this study, the impact of impingement distance, the distance from injector nozzle exit to the anvil connected to the force transducer, is characterized over a range of 2 - 12 mm. This characterization includes the impact of the distance on the momentum flux signal in both magnitude and shape. At longer impingement distances, it is hypothesized that a peak in momentum could occur due to increasing velocity of fuel injected as the pintle fully opens.
Technical Paper

Experimental Investigation of the Compression Ignition Process of High Reactivity Gasoline Fuels and E10 Certification Gasoline using a High-Pressure Direct Injection Gasoline Injector

2020-04-14
2020-01-0323
Gasoline compression ignition (GCI) technology shows potential to obtain high thermal efficiencies while maintaining relatively low soot and NOx emissions in light-duty engine applications. Recent experimental studies and numerical simulations have indicated that high reactivity gasoline-like fuels can further enable the benefits of GCI combustion. However, there is limited combustion data in the literature studying the gasoline compression ignition process at relevant in-cylinder conditions which are required for further optimizing combustion system designs. This study investigates the temporal and spatial evolution of the compression ignition process of various high reactivity gasolines with research octane numbers (RON) of 71, 74 and 82, as well as conventional RON 97 E10 gasoline fuel. Combustion visualizations were conducted in an optically accessible constant volume combustion chamber.
Technical Paper

Probing Spark Discharge Behavior in High-speed Cross-flows through Modeling and Experimentation

2020-04-14
2020-01-1120
This paper presents a combined numerical and experimental investigation of the characteristics of spark discharge in a spark-ignition engine. The main objective of this work is to gain insights into the spark discharge process and early flame kernel development. Experiments were conducted in an inert medium within an optically accessible constant-volume combustion vessel. The cross-flow motion in the vessel was generated using a previously developed shrouded fan. Numerical modeling was based on an existing discharge model in the literature developed by Kim and Anderson. However, this model is applicable to a limited range of gas pressures and flow fields. Therefore, the original model was evaluated and improved to predict the behavior of spark discharge at pressurized conditions up to 45 bar and high-speed cross-flows up to 32 m/s. To accomplish this goal, a parametric study on the spark channel resistance was conducted.
X