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High Speed Camera Based 3D Experimental Modal Analysis

University of Ljubljana-Domen Gorjup, Janko Slavic, Miha Boltezar
  • Technical Paper
  • 2020-01-1569
To be published on 2020-06-03 by SAE International in United States
High-speed camera systems in vibration measurements are typically limited to identifying motion perpendicular to the optical axis. Depth information, lost in the imaging process, can be recovered by using the recently introduced frequency domain triangulation and consequently full 3D deflection shapes can be obtained. This research presents the required theoretical background where the multiview image data is used for spatial small harmonic motion identification. Vibrations of an arbitrary-shaped specimen can be identified in the frequency domain using only a single, moving high-speed camera, extending the field-of-view of the established image-based vibration measurement methods. Real test cases are also presented.
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Study of thermal efficiency improvement by multi-hole nozzle

Hino Motors Ltd.-Kazunori Yoshitomi, Yoshihiro Funayama, Mori Ishii, Hiroshi Nakajima
  • Technical Paper
  • 2020-01-0304
To be published on 2020-04-14 by SAE International in United States
A truck and bus transportation which support logistics and people, diesel engines are highly expected to have high thermal efficiency and low exhaust emissions over the next few decades. Effective methods to achieve even higher thermal efficiency are to reduce a cooling loss from combustion chamber wall. A multi-hole diesel injector has a significant impact on improving engine thermal efficiency by enhancing a combustion activity and reducing a cooling loss. In this study, two types of diesel injectors – 8-hole and 14-hole - with the same flow rate were tested under heavy-duty diesel engine condition. Heat release rate, energy balance and engine emissions were investigated using the single-cylinder engine with displacement of 1,478 cc. Furthermore, an optical engine was used to observe quantitative spray penetration and flame development from shadowgraph imaging and analyze flame temperature by a two-color method. The results of the single-cylinder engine showed that the 14-hole injector exhibited higher indicated thermal efficiency thanks to lower cooling loss than 8-hole results. However, we observed a slightly higher exhaust loss in the case of…
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Digital Image Correlation Based Real-Time fatigue feedback System Study

Oakland University-Boyang Zhang, Wan Xu, Rong Wang, Wen Ma, Lianxiang Yang
  • Technical Paper
  • 2020-01-0539
To be published on 2020-04-14 by SAE International in United States
Fatigue testing is a specialized form of mechanical testing that is performed by applying cyclic loading to a coupon or structure. Two common forms of fatigue testing are load controlled high cycle and strain controlled low cycle fatigue. Some strain measurement device, such as extensometer, strain gage, that are often used as a feedback sensor on strain controlled fatigue test. However, in applications where strain controlled fatigue testing could face some extreme conditions as well as high temperature and unusual sizing which requires the strain measurement to be nondestructive and full field. While digital image correlation (DIC), an advanced optical measurement technique, has a decent solution on challenges of fatigue testing measurement. The problem is how to turn DIC from a measurement system to a feedback controller unit. Due to the developments in camera and computation techniques, the sequential process can now be performed as a parallel process. That means while the images are streamed from the camera to the computer the correlation and reconstruction can be performed at the same time. In this way…
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Tracking Panel Movement during Stamping Process using Advanced Optical Technology

Oakland University-Bicheng Guo, Xiaowan Zheng, Boyang Zhang, Rong Wang, Lianxiang Yang
  • Technical Paper
  • 2020-01-0541
To be published on 2020-04-14 by SAE International in United States
The metal panel is comprehensively applied in the automotive industry. A significant issue for the metal panel is the deflection when did the movement in the press line of the stamping process. Unpredictable deflection could result in the cut off of press line. In order to control the deflection in a safe zone, Finite element tools are used to simulate the panel transform process. However, the simulation needs experimental validation where conventional displacement measurement techniques could not satisfy the requirement of vast filed displacement and accuracy point tracking. In this study, multi-camera digital image correlation (DIC) systems have been developed to track a panel movement in the press line of the stamping process. There are some advantages for applying the DIC system, which is non-contact, full-field, high accuracy, and direct measurement techniques that provide the evaluation displacement of the metal panel and press line. Nevertheless, the traditional stereo DIC system (with two cameras) has a limited field of view, and the multi-camera DIC system expands the field of view and enables the measurement of panel…
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Isobaric Combustion for High Efficiency in an Optical Diesel Engine

King Abdullah University of Science & Technology-Gustav Nyrenstedt, Abdullah Al Ramadan, Qinglong Tang, Moez Ben Houidi, Bengt Johansson
Saudi Aramco-Jihad Badra, Emre Cenker
  • Technical Paper
  • 2020-01-0301
To be published on 2020-04-14 by SAE International in United States
Isobaric combustion has been proven a promising strategy for high efficiency as well as low nitrogen oxides emissions, particularly in heavy-duty Diesel engines. Previous single-cylinder research engine experiments have, however, shown high soot levels when operating isobaric combustion. The combustion itself and the emissions formation with this combustion mode are not well understood due to the complexity of multiple injections strategy. Therefore, experiments with an equivalent heavy-duty Diesel optical engine were performed in this study. Three different cases were compared, an isochoric heat release case and two isobaric heat release cases. One of the isobaric cases was boosted to reach the maximum in-cylinder pressure of the isochoric one. The second isobaric case kept the same boost levels as the isochoric case. Results showed that in the isobaric cases, liquid fuel was injected into burning gases. This resulted in shorter ignition delays and thus a poor mixing level. The lack of fuel/air mixing was clearly the main contributor to the high soot emissions observed in isobaric combustion. The lower heat losses of the isobaric strategy were…
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Importance of Turbulence-chemistry Interactions in Predicting Spray A End of Injection Phenomenon

University of Oxford-Xiaohang Fang, Riyaz Ismail, Nikola Sekularac, Martin Davy
  • Technical Paper
  • 2020-01-0779
To be published on 2020-04-14 by SAE International in United States
In this study, the role of turbulence-chemistry interaction in diesel spray auto-ignition, flame stabilisation and end of injection phenomenon is investigated under engine relevant Spray A conditions. A recently developed diesel spray combustion modelling approach, conditional source-term estimation (CSE-FGM), is coupled with Reynolds-averaged Navier-Stokes simulation (RANS) framework to study the details of spray combustion. The detailed chemistry mechanism is included in this approach through the flamelet generated manifold (FGM) method. Both unsteady and steady flamelet solutions are included in the manifold to account for the auto-ignition process and subsequent flame propagation in a diesel spray. Conditionally averaged chemical source terms are closed by the conditional scalars obtained in the CSE routine. Both non-reacting and reacting spray jets are computed over a wide range of Engine Combustion Network (ECN) diesel Spray A conditions. The reacting results are compared with simulations using homogeneous reactor combustion model and flamelet combustion model with the same chemical mechanism. The present study represents the first application of CSE for a diesel spray. The non-reacting liquid/vapour penetration, the mean and rms mixture…
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Comparative Analysis between a Barrier Discharge Igniter and a Streamer-Type Radio-Frequency Corona Igniter in an Optically Accessible Engine in Lean Operating Conditions

Federal-Mogul Powertrain Tenneco Group-Stefano Papi, Massimo Dal Re
Universita degli Studi di Perugia-Valentino Cruccolini, Gabriele Discepoli, Federico Ricci, Luca Petrucci, Carlo Grimaldi
  • Technical Paper
  • 2020-01-0276
To be published on 2020-04-14 by SAE International in United States
Among plasma-assisted ignition technologies, the Radio-Frequency (RF) corona family represents an interesting solution for the ability to extend the engine operating range. These systems generate transient, non-thermal plasma, which is able to enhance the combustion onset by means of thermal, kinetic and transport effects. Streamer-type RF corona discharge, at about 1 MHz, ignites the air-fuel mixture in multiple filaments, resulting in many different flame kernels. The main issue of this system is that at high electrode voltage and low combustion chamber pressure a transition between streamer and arc easily occurs: in this case transient plasma benefits are lost. A barrier discharge igniter (BDI), supplied with the same RF energy input, instead, is more breakdown-resistant, so that voltage can be raised to higher levels. In this work, a streamer-type RF corona igniter and a BDI were tested in a single-cylinder optical engine fueled with gasoline. Combustion behavior was characterized at stable, near-stable and unstable conditions (depending on IMEP coefficient of variation), increasing the air-fuel ratio starting from a near-stoichiometric mixture. For each test point the maximum…
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Advancements in Thermoplastic Optical Materials for Automotive Lighting Systems

Arkema Inc.-Altuglas International-Brian Cromer, Laura Thoma, Noah Macy, Charles Rissel
  • Technical Paper
  • 2020-01-0634
To be published on 2020-04-14 by SAE International in United States
Described are strategies to maximize the performance and efficiency of long path length acrylic optical elements through material selection and manufacturing optimization. Recent LED lamp designs include functional optical elements such as light pipes and dispersion optics that channel LED light through long optical path lengths (LOPL), 5-80 cm in length. Typically, these elements are manufactured from thermoplastic optical materials such as PMMA or PC through injection molding. However, conventional thermoplastic optical materials are not suitable for LOPL application due to insufficient luminous transmission and high absorption coefficients, resulting in inadequate lamp function and poor efficiency. Furthermore, the effects of molding conditions on LOPL performance are poorly understood. Recent advancements in acrylic technology produced optimized materials for LOPL signature lighting optics: Plexiglas® HT121-LPL® and V825T-LPL® resins. Compared to conventional acrylic resins, these optimized resins increase luminous transmission 95%-101% in a 60 cm light pipe and also improve spectral transmission uniformity. Additionally, optimization of injection molding parameters including screw speed, dwell time, injection speed, and barrel temperature further increase luminous transmission 3.0%-8.2%.
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Establishing Thermal Stability in an Optically-Accessible CIDI Engine

University of Wisconsin–Madison-Michael Groendyk, David Rothamer
  • Technical Paper
  • 2020-01-0789
To be published on 2020-04-14 by SAE International in United States
Optically-accessible engines are a key tool for the study of sprays, mixing, and ignition and combustion phenomena in internal combustion (IC) engines. Due to their construction, they are typically operated for limited durations, resulting in significant thermal transients in the in-cylinder surface temperatures and cycle-to-cycle in-cylinder gas temperature. This makes collection of highly repeatable data difficult and can introduce considerable uncertainty in the in-cylinder thermal conditions. In this paper, rigorous analyses of transient in-cylinder boundary conditions and in-cylinder gas temperature were performed in an optically-accessible compression-ignition engine. Piston surface thermometry, in-cylinder pressure measurements, and in-cylinder gas thermometry were employed to determine the engine warmup time required to reach a quasi-steady thermal state for motored operation over a range of intake air temperatures and pressures from 300-420 K and 100-300 kPa, respectively. The effect of fueling on thermal stability was investigated for single-injection mixing-controlled compression-ignition combustion utilizing a range of skip-fire ratios from 5:1 to 50:1 and loads from 0.8 to 10.1 bar gross indicated mean effective pressure. Both optical and metal pistons were studied. A…
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Optical study on the fuel spray characteristics of high-pressure isobaric combustion using four consecutive injections

King Abdullah University of Science & Technology-Qinglong Tang, Ramgopal Sampath, Priybrat Sharma, Gustav Nyrenstedt, Abdullah Al Ramadan, Moez Ben Houidi, Bengt Johansson, Gaetano Magnotti
Saudi Aramco-Jihad Badra
  • Technical Paper
  • 2020-01-1129
To be published on 2020-04-14 by SAE International in United States
High-pressure isobaric combustion using the double compression expansion concept was proposed to obtain higher brake thermal efficiency than the conventional diesel combustion. Experiments in metal engines have shown that four consecutive injections delivered by a single injector can achieve isobaric combustion. Improved understanding of the detailed fuel-air mixing with multiple consecutive injections is needed to optimize the isobaric combustion and reduce engine emissions. In this study, we explored the fuel spray characteristics of the four consecutive injections strategy using fuel-tracer planar laser-induced fluorescence (PLIF) imaging on a heavy-duty optical engine under non-reactive condition. Toluene of 2% by volume was added into the n-heptane fuel and served as the tracer. The fourth harmonic of a 10 Hz Nd:YAG laser was applied for excitation of toluene. One of the fuel sprays was bisected by the vertical laser sheet and visualized by a camera from the side view. The PLIF images of the premixed mixture formed by port fuel injection were used to normalize the direct-injection PLIF images and correct the effect of non-uniformity of the laser sheet.…