scholarly journals Imaging of Fuel-Film Evaporation and Combustion in a Direct-Injection Model Experiment

2019 ◽  
Author(s):  
Niklas Jüngst ◽  
Sebastian Kaiser
Keyword(s):  
Model Experiment ◽  
Direct Injection ◽  
Fuel Film ◽  
Film Evaporation ◽  
Injection Model

Combining Instantaneous Temperature Measurements and CFD for Analysis of Fuel Impingement on the DISI Engine Piston Top

2009 ◽  
Author(s):  
Kukwon Cho ◽  
Ronald O. Grover ◽  
Dennis Assanis ◽  
Zoran Filipi ◽  
Gerald Szekely ◽  
...  
Keyword(s):  
Film Thickness ◽  
Heat Loss ◽  
Cfd Simulation ◽  
Computational Study ◽  
Fluid Dynamic ◽  
Direct Injection ◽  
Negative Temperature ◽  
Fuel Injector ◽  
Fuel Film ◽  
Film Evaporation

A two-pronged experimental and computational study was conducted to explore the formation, transport, and vaporization of a wall film located on the piston surface within a four-valve, pent roof, direct-injection spark-ignition (DISI) engine, with the fuel injector located between the two intake valves. Negative temperature swings were observed at three piston locations during early injection, thus confirming the ability of fast-response thermocouples to capture the effects of impingement and heat loss associated with fuel film evaporation. Computational Fluid Dynamic (CFD) simulation results demonstrated that the fuel film evaporation process is extremely fast under conditions present during intake. Hence, the heat loss measured on the surface can be directly tied to the heating of the fuel film and its complete evaporation, with the wetted area estimated based on CFD predictions. This finding is critical for estimating the local fuel film thickness from measured heat loss. The simulated fuel film thickness and transport corroborated well temporally and spatially with measurements at thermocouple locations directly in the path of the spray, thus validating the spray and impingement models. Under the strategies tested, up to 23% of fuel injected impinges upon the piston and creates a fuel film with thickness of up to 1.2 μm. In summary, the study demonstrates the usefulness of heat flux measurements to quantitatively characterize the fuel film on the piston top and allows for validation of the CFD code.

Combining Instantaneous Temperature Measurements and CFD for Analysis of Fuel Impingement on the DISI Engine Piston Top

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Kukwon Cho ◽  
Ronald O. Grover ◽  
Dennis Assanis ◽  
Zoran Filipi ◽  
Gerald Szekely ◽  
...  
Keyword(s):  
Film Thickness ◽  
Heat Loss ◽  
Cfd Simulation ◽  
Computational Study ◽  
Direct Injection ◽  
Negative Temperature ◽  
Spark Ignition Engine ◽  
Fuel Injector ◽  
Fuel Film ◽  
Film Evaporation

A two-pronged experimental and computational study was conducted to explore the formation, transport, and vaporization of a wall film located at the piston surface within a four-valve, pent-roof, direct-injection spark-ignition engine, with the fuel injector located between the two intake valves. Negative temperature swings were observed at three piston locations during early injection, thus confirming the ability of fast-response thermocouples to capture the effects of impingement and heat loss associated with fuel film evaporation. Computational fluid dynamics (CFD) simulation results indicated that the fuel film evaporation process is extremely fast under conditions present during intake. Hence, the heat loss measured on the surface can be directly tied to the heating of the fuel film and its complete evaporation, with the wetted area estimated based on CFD predictions. This finding is critical for estimating the local fuel film thickness from measured heat loss. The simulated fuel film thickness and transport corroborated well temporally and spatially with measurements at thermocouple locations directly in the path of the spray, thus validating the spray and impingement models. Under the strategies tested, up to 23% of fuel injected impinges upon the piston and creates a fuel film with thickness of up to 1.2 μm. In summary, the study demonstrates the usefulness of heat flux measurements to quantitatively characterize the fuel film on the piston top and allows for validation of the CFD code.

scholarly journals Effect of engine conditions and injection timing on piston-top fuel films for stratified direct-injection spark-ignition operation using E30

2019 ◽  
Vol 21 (2) ◽  
pp. 302-318 ◽  
Author(s):  
Carl-Philipp Ding ◽  
David Vuilleumier ◽  
Namho Kim ◽  
David L Reuss ◽  
Magnus Sjöberg ◽  
...  
Keyword(s):  
Refractive Index ◽  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Injection Timing ◽  
Fuel Film ◽  
Index Matching ◽  
Refractive Index Matching ◽  
Wall Wetting ◽  
Direct Injection Spark Ignition

Mid-level ethanol/gasoline blends can provide knock resistance benefits for stoichiometric spark-ignition engine operation, but previous studies have identified challenges associated with spray impingement and wall wetting, leading to excessive particulate matter emissions. At the same time, stratified-charge spark-ignition operation can provide increased thermal efficiency, but care has to be exercised to avoid excessive in-cylinder soot formation. In support of the use of mid-level ethanol/gasoline blends in advanced spark-ignition engines, this study presents spray and fuel-film measurements in a direct-injection spark-ignition engine operated with a 30 vol.%/70 vol.% ethanol/gasoline blend (E30). Crank-angle resolved fuel-film measurements at the piston surface are conducted using two different implementations of the refractive index matching technique. A small-angle refractive index matching implementation allows quantification of the wetted area, while a large-angle refractive index matching implementation enables semi-quantitative measurements of fuel-film thickness and volume, in addition to fuel-film area. The fuel-film measurements show that both the amount of fuel deposited on the piston and the shape of the fuel-film patterns are strongly influenced by the injection timing, duration, intake pressure, and coolant temperature. For combinations of high in-cylinder gas density and long injection duration, merging of the individual spray plumes, commonly referred to as spray collapse, can cause a dramatic change to the shape and thickness of the wall fuel films. Overall, the study provides guidance to engine designers aiming at minimizing wall wetting through tailored combinations of injection timings and durations.

Research on Transient Fuel-Film Compensation Control Strategy for a Port-Fuel-Injected Engine

2011 ◽  
Vol 383-390 ◽  
pp. 1195-1201
Author(s):  
Jian Hao Zhou ◽  
Yin Nan Yuan ◽  
Kai Wu ◽  
Jia Yi Du
Keyword(s):  
Perturbation Method ◽  
Control Strategy ◽  
Wave Perturbation ◽  
Fuel Film ◽  
Transient Conditions ◽  
Evaporation Model ◽  
Square Wave ◽  
Film Evaporation ◽  
Compensation Control ◽  
New Strategy

The fuel-film evaporation model and transient fuel-film compensator model were established. By virtue of Simulink, the validity of above models were verified. The square wave perturbation method was introduced. Basing numerous calibration, the fuel-film compensation strategy including zoned compensation and damping factors ware proposed. This new strategy can compensate in-cylinder fuel fluctuation effectively during transient conditions.

scholarly journals STUDY OF MULTI-ZONE THERMODYNAMIC MODEL DIRECT-INJECTION COMPRESSION IGNITION ENGINES

2020 ◽  
Vol 20 (4) ◽  
pp. 345-361
Author(s):  
Haydar M. Razoqe ◽  
Mahmoud A. Mashkour
Keyword(s):  
Simulation Model ◽  
Engine Speed ◽  
Direct Injection ◽  
Compression Ignition ◽  
Compression Ignition Engines ◽  
Programming Tools ◽  
Injection Model ◽  
The Rich ◽  
Thermodynamic Equations ◽  
Good Agreement

The present research investigated multi-zone single-cylinder four-stroke direct-injection model. The model simulates closed cycle processes and describes the combustion behavior by employing thermodynamic equations of a penetration spray theories. The model has been coded on the base of the programming tools of Matlab software. In this simulation model, the combustion events is divided into five zones, in order to determine the amount of fuel, access air, and amount of products in each zone. The simulation model, produced in this work, provides a more accurate framework for zero dimensional model by introducing physical zones within the model that correspond to the combustion structures in the engine. Comparison the results of the simulation model with other methods in the published researches shows that the behavior of engine parameters with theoretical and experimental earlier works has a good agreement. From the simulation model results can be concluded that, there is a change in the limits of the combustion zones with changing engine speed, amount of injected fuel, intake air pressure, and temperature, especially in the rich premixed burn zone.    

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