Methodology for Optical Engine Characterization by Means of the Combination of Experimental and Modeling Techniques

Optical engines allow for the direct visualization of the phenomena taking place in the combustion chamber and the application of optical techniques for combustion analysis, which makes them invaluable tools for the study of advanced combustion modes aimed at reducing pollutant emissions and increasing efficiency. An accurate thermodynamic analysis of the engine performance based on the in-cylinder pressure provides key information regarding the gas properties, the heat release, and the mixing conditions. If, in addition, optical access to the combustion process is provided, a deeper understanding of the phenomena can be derived, allowing the complete assessment of new injection-combustion strategies to be depicted. However, the optical engine is only useful for this purpose if the geometry, heat transfer, and thermodynamic conditions of the optical engine can mimic those of a real engine. Consequently, a reliable thermodynamic analysis of the optical engine itself is mandatory to accurately determine a number of uncertain parameters among which the effective compression ratio and heat transfer coefficient are of special importance. In the case of optical engines, the determination of such uncertainties is especially challenging due to their intrinsic features regarding the large mechanical deformations of the elongated piston caused by the pressure, and the specific thermal characteristics that affect the in-cylinder conditions. In this work, a specific methodology for optical engine characterization based on the combination of experimental measurements and in-cylinder 0D modeling is presented. On one hand, the method takes into account the experimental deformations measured with a high-speed camera in order to determine the effective compression ratio; on the other hand, the 0D thermodynamic analysis is used to calibrate the heat transfer model and to determine the rest of the uncertainties based on the minimization of the heat release rate residual in motored conditions. The method has been demonstrated to be reliable to characterize the optical engine, providing an accurate in-cylinder volume trace with a maximum deformation of 0.5 mm at 80 bar of peak pressure and good experimental vs. simulated in-cylinder pressure fitting.

[1]  Vicente Bermúdez,et al.  Sensitivity of diesel engine thermodynamic cycle calculation to measurement errors and estimated parameters , 2000 .

[2]  William Thielicke,et al.  PIVlab – Towards User-friendly, Affordable and Accurate Digital Particle Image Velocimetry in MATLAB , 2014 .

[3]  Gerardo Valentino,et al.  Evaluation of different methods for combined thermodynamic and optical analysis of combustion in spark ignition engines , 2014 .

[4]  Ulf Aronsson,et al.  Processes in Optical Diesel Engines - Emissions Formation and Heat Release , 2011 .

[5]  Ricardo Novella,et al.  An Investigation of the Engine Combustion Network ‘Spray B’ in a Light Duty Single Cylinder Optical Engine , 2018 .

[6]  J. Sodré,et al.  Impacts of replacement of engine powered vehicles by electric vehicles on energy consumption and CO 2 emissions , 2018 .

[7]  Pablo Olmeda,et al.  A complete 0D thermodynamic predictive model for direct injection diesel engines , 2011 .

[8]  Octavio Armas,et al.  Influence of measurement errors and estimated parameters on combustion diagnosis , 2006 .

[9]  Cosmin E. Dumitrescu,et al.  Flame development analysis in a diesel optical engine converted to spark ignition natural gas operation , 2018, Applied Energy.

[10]  Adrian Irimescu,et al.  Investigation on the effects of butanol and ethanol fueling on combustion and PM emissions in an optically accessible DISI engine , 2018 .

[11]  Öivind Andersson,et al.  Influence of spatial and temporal distribution of Turbulent Kinetic Energy on heat transfer coefficient in a light duty CI engine operating with Partially Premixed Combustion , 2018 .

[12]  B. Johansson,et al.  Impact of Mechanical Deformation due to Pressure, Mass, and Thermal Forces on the In-Cylinder Volume Trace in Optical Engines of Bowditch Design , 2011 .

[13]  B. Johansson,et al.  Analysis of Errors in Heat Release Calculations Due to Distortion of the In-Cylinder Volume Trace from Mechanical Deformation in Optical Diesel Engines , 2012 .

[14]  Sungwook Park,et al.  Estimation of CO2 emissions from heavy-duty vehicles in Korea and potential for reduction based on scenario analysis. , 2018, The Science of the total environment.

[15]  Jaime Martín,et al.  A new methodology for uncertainties characterization in combustion diagnosis and thermodynamic modelling , 2014 .

[16]  Morgan Heikal,et al.  Experimental study on an IC engine in-cylinder flow using different steady-state flow benches , 2017 .

[17]  Bengt Johansson,et al.  High-Speed Particle Image Velocimetry Measurement of Partially Premixed Combustion (PPC) in a Light Duty Engine for Different Injection Strategies , 2015 .

[18]  A. Gil,et al.  Study of Air Flow Interaction with Pilot Injections in a Diesel Engine by Means of PIV Measurements , 2017 .

[19]  X. Margot,et al.  Computational Study of Heat Transfer to the Walls of a DI Diesel Engine , 2005 .

[20]  Mingfa Yao,et al.  A comparative study on partially premixed combustion (PPC) and reactivity controlled compression ignition (RCCI) in an optical engine , 2019, Proceedings of the Combustion Institute.

[21]  Paul C. Miles,et al.  Characterization of Flow Asymmetry During the Compression Stroke Using Swirl-Plane PIV in a Light-Duty Optical Diesel Engine with the Re-entrant Piston Bowl Geometry , 2015 .

[22]  Alok Warey,et al.  Experimental and Numerical Studies of Bowl Geometry Impacts on Thermal Efficiency in a Light-Duty Diesel Engine , 2018 .

[23]  O. Armas,et al.  Diagnosis of DI Diesel combustion from in-cylinder pressure signal by estimation of mean thermodynamic properties of the gas , 1999 .

[24]  Paul C. Miles,et al.  In-Cylinder PIV Measurements in an Optical Light-Duty Diesel at LTC Conditions. , 2008 .