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Use of Nitric Acid to Control the NO2:NOX Ratio Within the Exhaust Composition Transient Operation Laboratory Exhaust Stream

Southwest Research Institute-Robert Henderson, Ryan Hartley, Cary Henry
  • Technical Paper
  • 2020-01-0371
To be published on 2020-04-14 by SAE International in United States
The Exhaust Composition Transient Operation Laboratory (ECTO-Lab) is a burner system developed at Southwest Research Institute (SwRI) for simulation of IC engine exhaust. The current system design requires metering and combustion of nitromethane in conjunction with the primary fuel source as the means of NOX generation. While this method affords highly tunable NOX concentrations even over transient cycles, no method is currently in place for dictating the speciation of nitric oxide (NO) and nitrogen dioxide (NO2) that constitute the NOX mixture. NOX generated through combustion of nitromethane is dominated by NO, and generally results in a NO2:NOX ratio of <5 %. Generation of any appreciable quantities of NO2 is therefore dependent on an oxidation catalyst to oxidize a fraction of the NO to NO2. Presented within this manuscript is a method for precise control of the NO2:NOX ratio within the ECTO-Lab exhaust stream by using nitric acid as the NOX precursor molecule in lieu of nitromethane. While decomposition of nitromethane generates NO as the dominate component of the NOX mixture, nitric acid decomposition produces primarily…
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Analytical approach to characterize the effect of engine control parameters and fuel properties on ACI operation in a GDI engine

Argonne National Laboratory-Johannes Rohwer, Ashish Shah, Toby Rockstroh
  • Technical Paper
  • 2020-01-1141
To be published on 2020-04-14 by SAE International in United States
Advanced compression ignition (ACI) operation in gasoline direct injection (GDI) engines is a promising concept to reduce fuel consumption and emissions at part load conditions. However, combustion phasing control and the limited operating range in ACI mode are a perennial challenge. In this study the combined impact of fuel properties and engine control strategies are investigated. A design of experiments method was implemented using a three level orthogonal array to determine the sensitivity of five engine control parameters on four engine response variables under low load ACI operation for three 98 RON gasoline fuels, exhibiting disparate chemical composition. Furthermore, the thermodynamic state of the compression histories was studied with the aid of the pressure-temperature framework and correlations were drawn to analogous HCCI experiments conducted in an instrumented CFR engine. Due to the compression ratio constraints imposed by knock limited SI operation, considerable intake temperature heating was required resulting in advanced compression ignition mode resulting in the intermediate to high temperature autoignition regime. The olefin containing fuel was found to require the least amount of intake…
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Large Eddy Simulations of Supercritical and Transcritical Jet Flows using Real Fluid Thermophysical Properties

King Abdullah University of Science & Technology-Hong G. Im
Universidad de Oviedo-Adrian Pandal
  • Technical Paper
  • 2020-01-1153
To be published on 2020-04-14 by SAE International in United States
A satisfactory understanding of the complex phenomena of supercritical jet mixing is still lacking. When the injected fuel temperature and pressure are at supercritical conditions, the fuel spray becomes similar to gas jet situation and it leads to steady shock structures (Mach disk). The negligible effect of the interfacial surface tension force due to the supercritical conditions produces a diffuse interface. In order to understand supercritical jet flows further, well resolved large eddy simulations (LES) of a n-dodecane jet mixing with surrounding nitrogen are conducted. A real fluid thermodynamic model is used to account for the fuel compressibility and variable thermophysical properties due to the solubility of ambient gas and liquid jet using the cubic Peng-Robinson equation of state (PR-EOS). A molar averaged homogeneous mixing rule is used to calculate the mixing properties. The thermodynamic model is coupled with a pressure-based solver to simulate multispecies reacting flows. The numerical model is based on a second order accurate method implemented in the open source OpenFOAM-6 software. First, to evaluate the present numerical model of sprays, 1D…
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Exergy Based Optimal Controller Design of a Spark-Ignition Internal Combustion Engine

CEAS Western Michigan University-Muataz Abotabik, Rick Meyer, Christopher Proctor
  • Technical Paper
  • 2020-01-0250
To be published on 2020-04-14 by SAE International in United States
Internal combustion engine (ICE) control techniques have been developed with only the first law of thermodynamics in mind, e.g. improving thermal efficiency, tracking specific load requirements, etc. The first law of thermodynamics does not account for the losses in work potential that are caused due to the in-cylinder high temperature thermodynamic processes irreversibilities. For instance, up to 25% of fuel exergy or fuel availability may be lost to irreversibilities during the combustion process. The second law of thermodynamics states that not all energy in an energy source is available to do work; its application evaluates the maximum available energy in that source after accounting for the losses caused by the irreversibilities. Therefore, including the exergy in an optimal engine control algorithm may lead to improved ICE thermal efficiencies. In this work, a model predictive controller (MPC) is developed based on the first and second laws of thermodynamics to control a detailed eight-cylinder ICE model developed in GT-Power. To make the controller practically applicable for eventual hardware in the loop (HiL) investigations, the GT-Power model is…
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Comparison of spray collapses from multi-hole and single-hole injectors using high-speed photography

Harbin Institute of Technology-Yitao Shen
Tsinghua University-Lu Xinhui, Yi Gong, Xiao Ma, Shijin Shuai, Omar Awad
  • Technical Paper
  • 2020-01-0321
To be published on 2020-04-14 by SAE International in United States
In this paper, the differences between multi-hole and single-hole spray contour under the same conditions were compared by using high-speed photography. The difference between the contour area of multi-hole and that of single-hole spray was used as a parameter to describe the degree of spray collapse. Three dimensionless parameters (i.e. degree of superheat, degree of undercooling, and nozzle pressure ratio) were applied to characterize inside-nozzle thermodynamic, outside-nozzle thermodynamic and kinetic factors, respectively. In addition, the relationship between the three dimensionless parameters and the spray collapse was analyzed. A semi-empirical equation was proposed for evaluation of the degree of collapse based on dimensionless parameters of flash and non-flash boiling sprays respectively.
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Statistical Analysis of the Results Obtained by Thermodynamic Methods for the Determination of TDC Offset in an Internal Combustion Engine

Deakin University-Faisal Lodi, Timothy Bodisco
Queensland University of Technology-Mohammad Jafari, Richard Brown
  • Technical Paper
  • 2020-01-1350
To be published on 2020-04-14 by SAE International in United States
Presented is a comprehensive evaluation of thermodynamic techniques used for the determination of top dead centre (TDC) in an internal combustion engine (ICE). This work thoroughly explores the assumptions made in thermodynamic calibration and assesses the impact these have through a rigorous sensitivity analysis, not previously attempted in any other study. The results of this work are presented as kernel density estimates (KDEs), an estimate of the probability density function (pdf), in order to offer both qualitative and quantitative assessments of the loss angle and the influence of the assumptions underpinning the loss angles determination. Thermodynamic loss angles ranging between -0.5°CA and -0.6°CA have been found for the engine under investigation.
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Air Induction Impact on Turbocharger Noise and Thermodynamic Performance

FCA US LLC-Shadi Saeed, Brian Butler, Mark Likich, Jeff Orzechowski
FEV Europe GmbH-Tobias Zimmermann
  • Technical Paper
  • 2020-01-0426
To be published on 2020-04-14 by SAE International in United States
The trend of improved FE and performance has led to industry growth of turbocharged engines and as a result, the need to address their undesirable attributes. This presents some unique engineering challenges as customer expectations for NVH, and other vehicle-level attributes, trend higher over time as well. Noise attenuation specific to turbocharged engines is uniquely challenging due to the types of noises they produce. Of specific concern, flow interaction between the induced air and compressor through a range of thermodynamic conditions can often result in objectionable "whoosh" noises within the Air Induction System (AIS). The traditional method for attenuation of this type of noise has been to use resonators which adds cost, weight and requires packaging space which is often at a premium in the under-hood environment. By improving our understanding of the root cause of the compressor whoosh noise, we hope to develop system design strategies that can prevent unwanted noise from being generated and avoid the need for traditional noise attenuation solutions. To investigate different flow metrics and their impact on compressor noise…

Ruthenium-Doped Thermoelectric Materials

  • Magazine Article
  • TBMG-35806
Published 2020-01-01 by Tech Briefs Media Group in United States

Innovators at NASA's Glenn Research Center have developed a novel thermoelectric material that raises the bar for solid-state power conversion devices. There is growing momentum in the aerospace and automotive industries to harvest energy from heat (such as exhaust from combustion) but advances have been hampered by the lack of environmental durability and performance levels of thermoelectric materials currently in use. Glenn's breakthrough material is a ruthenium-doped gadolinium orthotantalate that excels at directly converting heat into energy. More importantly, this material does not break down at higher temperatures or air environments, even without special coatings or inert packaging. Glenn's material enables designers to make great strides in developing solid-state power conversion devices for applications in aerospace, automotive, and power-generation industries.

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Influence of Inflow Boundary Conditions on High-Pressure Fuel Injection: Assessment Based on LES Approach

SAE International Journal of Engines

AVL List GmbH, Austria-Klaus Pachler, Marco Cristofaro
AVL List GmbH, Austria Friedrich-Alexander University Erlangen-Nürnberg, Germany-Amir Žilić
  • Journal Article
  • 03-13-02-0009
Published 2019-11-19 by SAE International in United States
The Engine Combustion Network case Spray A with a high-pressure fuel injection is at typical operating conditions of Diesel engines. Detailed pieces of information on this experiment are available, which supports a high-fidelity Large Eddy Simulation (LES) with real fluid thermodynamics. An internal injector flow simulation with the needle movement measured during the experiments is used to provide a realistic boundary condition for the fuel spray simulation. Two spray simulations have been conducted: one with a constant velocity profile and one with the velocity distribution obtained from a separate injector internal flow simulation. Peculiar emphasis is placed on the velocity and turbulence distribution to quantify the influence of spray inlet boundary conditions. The fuel injection is modeled with a single-phase approach applying adequate resolution to capture phase boundaries. Observations from simulation results indicate a significant influence of the inlet boundary conditions on fuel distribution and penetration length, turbulent mixing, and enthalpy propagation.
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Assessment of Energy Consumption and Range in Electric Vehicles with High Efficiency HVAC Systems Based on the Tesla Expander

University of Brescia-Paolo Iora, Alberto Cassago, Costante Invernizzi, Alessandro Copeta, Gioele Di Marcoberardino, Stefano Uberti
University of Florence-Daniele Fiaschi, Lorenzo Talluri
Published 2019-10-07 by SAE International in United States
Battery electric vehicles (BEVs) are considered one of the most promising solution to improve the sustainability of the transportation sector aiming at a progressive reduction of the dependence on fossil fuels and the associated local pollutants and CO2 emissions.Presently, the major technological obstacle to a large scale diffusion of BEVs, is the fairly low range, typically less than 300 km, as compared to classical gasoline and diesel engines. This limit becomes even more critical if the electric vehicle is operated in severe weather conditions, due to the additional energy consumption required by the cabin heating, ventilating, and air-conditioning (HVAC).The adoption of vapor-compression cycle, either in heat pump or refrigerator configuration, represents the state-of-the-art technology for HVAC systems in vehicles. Such devices typically employ an expansion valve to abruptly reduce the pressure causing the flash evaporation of the working fluid. This component, although necessary to provide the cooling effect, is also responsible of a significant exergy loss, which reduces the efficiency of the thermodynamic cycle.In this paper we study the possible benefits in terms of energy…
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