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Viewing 1 to 30 of 213
2018-04-03
Technical Paper
2018-01-0215
Zhuyong Yang, Sandesh Rao, Yanyu Wang, Jaideep Harsulkar, Ehsan Ansari, Niranjan Miganakallu Narasimhamurthy, Paul Dice, Jeffrey Naber, Yashodeep Lonari, Stanislaw Szwaja
The characteristics of knock metrics over a number of engine cycles can be an important reference for knock detection and control in internal combustion engines. In a spark-ignition (SI) engine, the stochastic nature of combustion knock has been shown to follow a log-normal distribution. However, this has been derived from experiments done with gasoline only and applicability of log-normal distribution to dual-fuel combustion knock has not been explored. Natural gas (NG) features itself with relatively high methane and octane numbers, hence, it can be applied as additional fuel blended with gasoline, which enables to increase knock limited spark advance thereby increasing thermal efficiency. To evaluate the efficacy and accuracy of log-normal distribution model for NG-gasoline blended fuel, a sweep of NG-gasoline fueling blending ratio by energy was conducted at two different speeds.
2018-04-03
Technical Paper
2018-01-0202
Devyani Patil, Yue Wang, Long Liang, Karthik Puduppakkam, Ahmed Hussein, Chitralkumar Naik, Ellen Meeks
Advanced research in Spark Ignition (SI) engine has been focused on dilute combustion concepts. For example, exhaust gas recirculation is used to lower both fuel consumption and pollutant emissions while maintaining or enhancing engine performance, durability and reliability. These advancements achieve higher engine efficiency but may deteriorate combustion stability. One symptom of instability is a large Cycle to Cycle Variations (CCV) in the in-cylinder flow and combustion metrics. Large-Eddy Simulation (LES) is a Computational Fluid Dynamics (CFD) method that may be used to quantify CCV through numerical prediction of the turbulent flow and combustion processes in the engine over many engine cycles. In this study, we focus on evaluating the capability of LES to predict the in-cylinder flows and gas exchange processes in a motored SI engine installed with a transparent combustion chamber (TCC), comparing with recently published data.
2018-04-03
Technical Paper
2018-01-0276
Le Zhao, Roberto Torelli, Xiucheng Zhu, Jeffrey Naber, Seong-Young Lee, Sibendu Som, Riccardo Scarcelli, Mehdi Raessi
The necessity to study spray-wall interaction in internal combustion engines is driven by the evidence that fuel sprays impinge on chamber and piston surfaces resulting in the formation of wall films. This, in turn, may influence the air-fuel mixing and increase the hydrocarbon and particulate matter emissions. This work reports an experimental and numerical study on spray-wall impingement and liquid film formation in a constant volume combustion vessel. Diesel and n-heptane were selected as test fuels and injected from a side-mounted single-hole diesel injector at pressures of 120, 150, and 180 MPa on a flat transparent window. Ambient and plate temperatures were set at 423 K, the fuel temperature at 363 K, and the ambient densities at 14.8, 22.8, and 30 kg/m3. Simultaneous Mie scattering and schlieren imaging were carried out in the experiment to visually track the spray-wall interaction process.
2018-04-03
Technical Paper
2018-01-0289
Le Zhao, Nitisha Ahuja, Xiucheng Zhu, Zhihao Zhao, Seong-Young Lee
This paper aims to provide the experimental and numerical investigation of a single fuel droplet impingement on the different wall conditions to understand the detailed impinging dynamic process. The experimental work was carried out at the room temperature and pressure except for the variation of the impinged wall temperature. A high-speed camera was employed to capture the silhouette of the droplet impinging on wall process against a collimated light. Water, diesel, and n-heptane were considered as three different droplets and injected from a precision syringe pump with the volume flow rate of 0.2 mL/min at various impact Weber numbers. The impingement outcomes after droplet impacting on the wall include stick, spread, rebound and splash, which depend on the controlling parameters of Weber number, Reynolds number, liquid and surface properties, etc.
2018-04-03
Technical Paper
2018-01-0312
Le Zhao, Zhihao Zhao, Xiucheng Zhu, Nitisha Ahuja, Jeffrey Naber, Seong-Young Lee
Film formation in spray-wall impingement process plays a critical role in engine performance and emissions. In this paper, the fuel film formation and the relevant film characteristics resulting from the liquid spray impinging on a flat plate were investigated in a constant volume combustion vessel by Refractive Index Matching (RIM) technique. The liquid film thickness was firstly calibrated with two different proportional mixtures (5 % dodecane and 95 % n-heptane; 10 % dodecane and 90 % n-heptane) pumped out from a precise syringe to achieve an accurate calibration result. The n-heptane fuel from a side-mounted single-hole diesel injector was then injected on a rough glass with the same optical setup, the distance between the injector tip and impinging plate is set to 33.65 mm. The ambient temperature and the plate temperature are set to 423 K with the fuel temperature of 363 K.
2018-04-03
Technical Paper
2018-01-0304
Meng Tang, Yuanjiang Pei, Yu Zhang, Tom Tzanetakis, Michael Traver, David Cleary, Shaoping Quan, Jeffrey Naber, Seong-Young Lee
Accurate modeling of fuel spray behavior at diesel engine conditions requires well-characterized boundary conditions Among those conditions, the spray cone angle is important due to its impact on the spray mixing process and flame lift-off locations, and subsequent soot formation. It is also a highly dynamic variable, but existing correlations of spray cone angle have been mainly developed for quasi-steady state and for use with diesel fuels at relatively low injection pressures. The objective of this study is to develop spray cone angle correlations for both diesel and a light-end gasoline fuel over a wide range of diesel-engine operating conditions that are capable of capturing both the transient and quasi-steady state processes. For this study, two important macroscopic characteristics of solid cone sprays, spray cone angle and spray penetration, were measured using a single-hole heavy-duty injector using two fuels at diesel engine conditions.
2018-04-03
Technical Paper
2018-01-0208
Yanyu Wang, Jiongxun Zhang, Zhuyong Yang, Xin Wang, Paul Dice, Mahdi Shahbakhti, Jeffrey Naber, Michael Czekala, Qiuping Qu, Garlan Huberts
Tumble motion plays a significant role in modern spark-ignition (SI) engines in that it increases mixing of air/fuel for homogeneous combustion and increases flame propagation for higher thermal efficiency and lower combustion variability. Cycle-by-cycle variations in the flow near the spark plug introduce variability to the initial flame kernel development, stretching, and convection and this variability is carried over to the entire combustion process. The design of current direct injection spark ignition (DI SI) engines aim to have a tumble flow in the vicinity of the spark plug at the time of ignition. This work investigates how the flow condition changes in the vicinity of the spark plug throughout the compression stroke via particle imaging velocimetry (PIV) and high speed imaging of a long ignition discharge arc channel and its stretching. The influence of tumble level and of fuel injection timing and fuel injection pressure are studied.
2018-01-19
Journal Article
2018-01-9077
Arya Yazdani, Mehran Bidarvatan
Power split in Fuel Cell Hybrid Electric Vehicles (FCHEVs) has been controlled using different strategies ranging from rule-based to optimal control. Dynamic Programming (DP) and Model Predictive Control (MPC) are two common optimal control strategies used in optimization of the power split in FCHEVs with a trade-off between global optimality of the solution and online implementation of the controller. In this paper, both control strategies are developed and tested on a FC/battery vehicle model, and the results are compared in terms of total energy consumption. In addition, the effects of the MPC prediction horizon length on the controller performance are studied. Results show that by using the DP strategy, up to 12% less total energy consumption is achieved compared to MPC for a charge sustaining mode in the Urban Dynamometer Driving Schedule (UDDS) drive cycle.
2017-09-04
Technical Paper
2017-24-0039
Daniele Piazzullo, Michela Costa, Youngchul Ra, Vittorio ROCCO, Ankith Ullal
Abstract Bio-derived fuels are drawing more and more attention in the internal combustion engine (ICE) research field in recent years. Those interests in use of renewable biofuels in ICE applications derive from energy security issues and, more importantly, from environment pollutant emissions concerns. High fidelity numerical study of engine combustion requires advanced computational fluid dynamics (CFD) to be coupled with detailed chemical kinetic models. This task becomes extremely challenging if real fuels are taken into account, as they include a mixture of hundreds of different hydrocarbons, which prohibitively increases computational cost. Therefore, along with employing surrogate fuel models, reduction of detailed kinetic models for multidimensional engine applications is preferred. In the present work, a reduced mechanism was developed for primary reference fuel (PRF) using the directed relation graph (DRG) approach.
2017-06-05
Technical Paper
2017-01-1845
Jon Furlich, Jason Blough, Darrell Robinette
Abstract When a manual transmission (MT) powertrain is subjected to high speeds and high torques, the vehicle driveshaft, and other components experience an increase in stored potential energy. When the engine and driveshaft are decoupled during an up or down shift, the potential energy is released causing clunk during the shift event. The customer desires a smooth shift thus reduction of clunk will improve experience and satisfaction. In this study, a six-speed MT, rear-wheel-drive (RWD) passenger vehicle was used to experimentally capture acoustic and vibration data during the clunk event. To replicate the in-situ results, additional data was collected and analyzed for powertrain component roll and pitch. A lumped parameter model of key powertrain components was created to replicate the clunk event and correlate with test data. The lumped parameter model was used to modify clutch tip-out parameters, which resulted in reduced prop shaft oscillations.
2017-06-05
Journal Article
2017-01-1816
Mahsa Asgarisabet, Andrew Barnard
Abstract Carbon Nanotube (CNT) thin film speakers produce sound with the thermoacoustic effect. Alternating current passes through the low heat capacity CNT thin film changing the surface temperature rapidly. CNT thin film does not vibrate; instead it heats and cools the air adjacent to the film, creating sound pressure waves. These speakers are inexpensive, transparent, stretchable, flexible, magnet-free, and lightweight. Because of their novelty, developing a model and better understanding the performance of CNT speakers is useful in technology development in applications that require ultra-lightweight sub-systems. The automotive industry is a prime example of where these speakers can be enabling technology for innovative new component design. Developing a multi-physics (Electrical-Thermal-Acoustical) FEA model, for planar CNT speakers is studied in this paper. The temperature variation on the CNT thin film is obtained by applying alternating electrical current to the CNT film.
2017-06-05
Technical Paper
2017-01-1895
Troy Bouman, Andrew Barnard, Joshua Alexander
Abstract Compared to moving coil loudspeakers, carbon nanotube (CNT) loudspeakers are extremely lightweight and are capable of creating sound over a broad frequency range (1 Hz to 100 kHz). The thermoacoustic effect that allows for this non-vibrating sound source is naturally inefficient and nonlinear. Signal processing techniques are one option that may help counteract these concerns. Previous studies have evaluated a hybrid efficiency metric, the ratio of the sound pressure level at a single point to the input electrical power. True efficiency is the ratio of output acoustic power to the input electrical power. True efficiency data are presented for two new drive signal processing techniques borrowed from the hearing aid industry. Spectral envelope decimation of an AC signal operates in the frequency domain (FCAC) and dynamic linear frequency compression of an AC signal operates in the time domain (TCAC). Each type of processing affects the true efficiency differently.
2017-03-28
Journal Article
2017-01-0001
Ming Cheng, Bo Chen
Abstract This paper studies the hardware-in-the-loop (HiL) design of a power-split hybrid electric vehicle (HEV) for the research of HEV lithiumion battery aging. In this paper, an electrochemical model of a lithium-ion battery pack with the characteristics of battery aging is built and integrated into the vehicle model of Autonomie® software from Argonne National Laboratory. The vehicle model, together with the electrochemical battery model, is designed to run in a dSPACE real-time simulator while the powertrain power distribution is managed by a dSPACE MicroAutoBoxII hardware controller. The control interface is designed using dSPACE ControlDesk to monitor the real-time simulation results. The HiL simulation results with the performance of vehicle dynamics and the thermal aging of the battery are presented and analyzed.
2017-03-28
Technical Paper
2017-01-0672
Yanyu Wang, Jiongxun Zhang, Paul Dice, Xin Wang, Mahdi Shahbakhti, Jeffrey Naber, Michael Czekala, Qiuping Qu, Garlan Huberts
Abstract The effect of flow direction towards the spark plug electrodes on ignition parameters is analyzed using an innovative spark aerodynamics fixture that enables adjustment of the spark plug gap orientation and plug axis tilt angle with respect to the incoming flow. The ignition was supplied by a long discharge high energy 110 mJ coil. The flow was supplied by compressed air and the spark was discharged into the flow at varying positions relative to the flow. The secondary ignition voltage and current were measured using a high speed (10MHz) data acquisition system, and the ignition-related metrics were calculated accordingly. Six different electrode designs were tested. These designs feature different positions of the electrode gap with respect to the flow and different shapes of the ground electrodes. The resulting ignition metrics were compared with respect to the spark plug ground strap orientation and plug axis tilt angle about the flow direction.
2017-03-28
Journal Article
2017-01-0680
Yanyu Wang, Jiongxun Zhang, Xin Wang, Paul Dice, Mahdi Shahbakhti, Jeffrey Naber, Michael Czekala, Qiuping Qu, Garlan Huberts
Abstract The influence of spark plug orientation on early flame kernel development is investigated in an optically accessible gasoline direct injection homogeneous charged spark ignition engine. This investigation provides visual understanding and statistical characterization of how spark plug orientation impacts the early flame kernel and thus combustion phasing and engine performance. The projected images of flame kernel were captured through natural flame chemiluminescence with a high-speed camera at 10,000 frames per second, and the ignition secondary discharge voltage and current were measured with a 10 MHz DAQ system. The combustion metrics were determined using measurement from a piezo-electric in-cylinder pressure transducer and real-time engine combustion analyzer. Three spark plug orientations with two different electrode designs were studied. The captured images of the flame were processed to yield 2D and 1D probability distributions.
2017-03-28
Technical Paper
2017-01-1199
Khalid Khan, Bin Zhou, Amir Rezaei
Abstract A high voltage battery is an essential part of hybrid electric vehicles (HEVs). It is imperative to precisely estimate the state of charge (SOC) and state of health (SOH) of battery in real time to maintain reliable vehicle operating conditions. This paper presents a method of estimating SOC and SOH through the incorporation of current integration, voltage translation, and Ah-throughput. SOC estimation utilizing current integration is inadequate due to the accumulation of errors over the period of usage. Thus voltage translation of SOC is applied to rectify current integration method which improves the accuracy of estimation. Voltage translation data is obtained by subjecting the battery to hybrid pulse power characterization (HPPC) test. The Battery State of Health was determined by semi-empirical model combined with accumulated Ah-throughput method. Battery state of charge was employed as an input to estimate damages accumulated to battery aging through a real-time model.
2017-03-28
Technical Paper
2017-01-1252
Ming Cheng, Lei Feng, Bo Chen
Abstract This paper studies the nonlinear model predictive control for a power-split Hybrid Electric Vehicle (HEV) power management system to improve the fuel economy. In this paper, a physics-based battery model is built and integrated with a base HEV model from Autonomie®, a powertrain and vehicle model architecture and development software from Argonne National Laboratory. The original equivalent circuit battery model from the software has been replaced by a single particle electrochemical lithium ion battery model. A predictive model that predicts the driver’s power request, the battery state of charge (SOC) and the engine fuel consumption is studied and used for the nonlinear model predictive controller (NMPC). A dedicated NMPC algorithm and its solver are developed and validated with the integrated HEV model. The performance of the NMPC algorithm is compared with that of a rule-based controller.
2017-03-28
Technical Paper
2017-01-1699
Luting Wang, Bo Chen
Abstract Vehicle-to-Grid (V2G) service has a potential to improve the reliability and stability of the electrical grid due to the ability of providing bi-directional power flow from/to the grid. However, frequent charging/discharging may impact the battery lifetime. This paper presents the analysis of battery degradation in three scenarios. In the first scenario, different battery capacities are considered. In the second scenario, the battery degradation with various depth of discharge (DOD) are studied. In the third scenario, the capacity loss due to different charging regime are compared. The charging/discharging of plug-in electric vehicles (PEVs) are simulated in a single-phase microgrid system integrated with a photovoltaics (PV) farm, an energy storage system (ESS), and ten electric vehicle service equipment (EVSE).
2017-03-28
Technical Paper
2017-01-1702
Piyush Aggarwal, Bo Chen, Jason Harper
Abstract The increased market share of electric vehicles and renewable energy resources have raised concerns about their impact on the current electrical distribution grid. To achieve sustainable and stable power distribution, a lot of effort has been made to implement smart grids. This paper addresses Demand Response (DR) load control in a smart grid using Internet of Things (IoT) technology. A smart grid is a networked electrical grid which includes a variety of components and sub-systems, including renewable energy resources, controllable loads, smart meters, and automation devices. An IoT approach is a good fit for the control and energy management of smart grids. Although there are various commercial systems available for smart grid control, the systems based on open sources are limited. In this study, we adopt an open source development platform named Node-RED to integrate DR capabilities in a smart grid for DR load control. The DR system employs the OpenADR standard.
2017-03-28
Journal Article
2017-01-1153
Ali Solouk, Mohammad Shakiba-herfeh, Mahdi Shahbakhti
Abstract Low Temperature Combustion (LTC) engines are promising to improve powertrain fuel economy and reduce NOx and soot emissions by improving the in-cylinder combustion process. However, the narrow operating range of LTC engines limits the use of these engines in conventional powertrains. The engine’s limited operating range can be improved by taking advantage of electrification in the powertrain. In this study, a multi-mode LTC-SI engine is integrated with a parallel hybrid electric configuration, where the engine operation modes include Homogeneous Charge Compression Ignition (HCCI), Reactivity Controlled Compression Ignition (RCCI), and conventional Spark Ignition (SI). The powertrain controller is designed to enable switching among different modes, with minimum fuel penalty for transient engine operations.
2017-03-28
Journal Article
2017-01-0833
Meng Tang, Jiongxun Zhang, Xiucheng Zhu, Kyle Yeakle, Henry Schmidt, Seong-Young Lee, Jeffrey Naber, Cody Squibb
Abstract 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.
2017-03-28
Technical Paper
2017-01-0781
Philip Zoldak, Jeffrey Naber
Abstract The increased availability of natural gas (NG) in the United States (US) and its relatively low cost versus diesel fuel has increased interest in the conversion of medium duty (MD) and heavy duty (HD) engines to NG fueled combustion systems. The aim for development for these NG engines is to realize fuel cost savings and increase operating range while reduce harmful emissions and maintaining durability. Traditionally, port-fuel injection (PFI) or premixed NG spark-ignited (SI) combustion systems have been used for light duty LD, and MD engines with widespread use in the US and Europe [1]. However, this technology exhibits poor thermal efficiency and is load limited due to knock phenomenon that has prohibited its use for HD engines. Spark Ignited Direct Injection (SIDI) can be used to create a partially stratified combustion (PSC) mixture of NG and air during the compression stroke.
2017-03-28
Technical Paper
2017-01-0767
Jayant Kumar Arora, Mahdi Shahbakhti
Abstract Real-time control of Reactivity Controlled Compression Ignition (RCCI) during engine load and speed transient operation is challenging, since RCCI combustion phasing depends on nonlinear thermo-kinetic reactions that are controlled by dual-fuel reactivity gradients. This paper discusses the design and implementation of a real-time closed-loop combustion controller to maintain optimum combustion phasing during RCCI transient operations. New algorithms for real-time in-cylinder pressure analysis and combustion phasing calculations are developed and embedded on a Field Programmable Gate Array (FPGA) to compute RCCI combustion and performance metrics on cycle-by-cycle basis. This cycle-by-cycle data is then used as a feedback to the combustion controller, which is implemented on a real-time processor. A computationally efficient algorithm is introduced for detecting Start of Combustion (SOC) for the High Temperature Heat Release (HTHR) or main-stage heat release.
2017-03-28
Journal Article
2017-01-0854
Le Zhao, Roberto Torelli, Xiucheng Zhu, Riccardo Scarcelli, Sibendu Som, Henry Schmidt, Jeffrey Naber, Seong-Young Lee
Abstract 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).
2017-03-28
Technical Paper
2017-01-0852
Sathya Prasad Potham, Le Zhao, Seong-Young Lee
Abstract This paper aims to extend the existing Volume of Fluid (VOF) model by implementing an evaporation sub-model in an open source Computational Fluid Dynamics (CFD) software, OpenFOAM. The paper applies the new model to numerically study the evaporation of spherical n-heptane droplets impinging on a hot wall at atmospheric pressure and a temperature above the Leidenfrost temperature. Volume of Fluid (VOF) method is chosen to track the liquid gas interface and the capability of VOF method implemented in interDyMFoam solver of OpenFOAM to simulate hydrodynamics during droplet-droplet interaction and droplet-film interaction is explored. Firstly, the in-built solver is used to simulate problems in isothermal conditions and the simulation results are compared qualitatively with the published results to validate the solver. A numerical method for modeling heat and mass transfer during evaporation is implemented in conjunction with the VOF.
2017-03-28
Technical Paper
2017-01-0527
Arya Yazdani, Jeffrey Naber, Mahdi Shahbakhti, Paul Dice, Chris Glugla, Stephen Cooper, Douglas McEwan, Garlan Huberts
An accurate estimation of cycle-by-cycle in-cylinder mass and the composition of the cylinder charge is required for spark-ignition engine transient control strategies to obtain required torque, Air-Fuel-Ratio (AFR) and meet engine pollution regulations. Mass Air Flow (MAF) and Manifold Absolute Pressure (MAP) sensors have been utilized in different control strategies to achieve these targets; however, these sensors have response delay in transients. As an alternative to air flow metering, in-cylinder pressure sensors can be utilized to directly measure cylinder pressure, based on which, the amount of air charge can be estimated without the requirement to model the dynamics of the manifold.
2017-03-28
Technical Paper
2017-01-0553
Lorenzo Sforza, Tommaso Lucchini, Angelo Onorati, Xiucheng Zhu, Seong-Young Lee
Abstract Objective of this work is the incorporation of the flame stretch effects in an Eulerian-Lagrangian model for premixed SI combustion in order to describe ignition and flame propagation under highly inhomogeneous flow conditions. To this end, effects of energy transfer from electrical circuit and turbulent flame propagation were fully decoupled. The first ones are taken into account by Lagrangian particles whose main purpose is to generate an initial burned field in the computational domain. Turbulent flame development is instead considered only in the Eulerian gas phase for a better description of the local flow effects. To improve the model predictive capabilities, flame stretch effects were introduced in the turbulent combustion model by using formulations coming from the asymptotic theory and recently verified by means of DNS studies. Experiments carried out at Michigan Tech University in a pressurized, constant-volume vessel were used to validate the proposed approach.
2017-03-28
Journal Article
2017-01-0271
Robert Jane, Gordon G. Parker, Wayne Weaver, Ronald Matthews, Denise Rizzo, Michael Cook
Abstract This paper considers optimal power management during the establishment of an expeditionary outpost using battery and vehicle assets for electrical generation. The first step in creating a new outpost is implementing the physical protection and barrier system. Afterwards, facilities that provide communications, fires, meals, and moral boosts are implemented that steadily increase the electrical load while dynamic events, such as patrols, can cause abrupt changes in the electrical load profile. Being able to create a fully functioning outpost within 72 hours is a typical objective where the electrical power generation starts with batteries, transitions to gasoline generators and is eventually replaced by diesel generators as the outpost matures.
2016-10-17
Technical Paper
2016-01-2201
Meng Tang, Le Zhao, Seong-Young Lee, Jeffrey Naber
Abstract Extensive studies have addressed diesel sprays under non-vaporizing, vaporizing and combusting conditions respectively, but further insights into the mechanism by which combustion alters the macroscopic characteristics including the spray penetration and the shape of the spray under diesel engine conditions are needed. Contradictory observations are reported in the literature regarding the combusting diesel spray penetration compared to the inert conditions, and it is an objective of this study to provide further insights and analyses on the combusting spray characteristics by expanding the range of operating parameters. Parameters varied in the studies are charge gas conditions including oxygen levels of 0 %, 15%, 19%, charge densities of 22.8 & 34.8 kg/m3, and charge temperatures of 800, 900 & 1050 K for injection pressures of 1200, 1500, and 1800 bar with a single-hole injector with a nozzle diameter of 100 μm.
2016-04-05
Technical Paper
2016-01-0855
Xiucheng Zhu, Sanjeet Limbu, Khanh Cung, William De Ojeda, Seong-Young Lee
Abstract Dimethyl Ether (DME) is considered a clean alternative fuel to diesel due to its soot-free combustion characteristics and its capability to be produced from renewable energy sources rather than fossil fuels such as coal or petroleum. To mitigate the effect of strong wave dynamics on fuel supply lines caused due to the high compressibility of DME and to overcome its low lubricity, a hydraulically actuated electronic unit injector (HEUI) with pressure intensification was used. The study focuses on high pressure operation, up to 2000 bar, significantly higher than pressure ranges reported previously with DME. A one-dimensional HEUI injector model is built in MATLAB/SIMULINK graphical software environment, to predict the rate of injection (ROI) profile critical to spray and combustion characterization.
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