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Viewing 1 to 30 of 5811
2015-04-14
Technical Paper
2015-01-0927
Luca Marchitto, Gerardo Valentino, Simona Merola, Cinzia Tornatore
The use of alcohols as alternative to gasoline for fuelling spark-ignition (SI) engines is widespread. Growing interest is paid for n-butanol because of its characteristics that are similar to gasoline, if compared with other alcohols. This paper reports the results concerning an experimental investigation on velocity fields of alcohol sprays injected by a 6-hole nozzle for Direct Injection Spark Ignition (DISI) Engine. 2D Mie-scattering Particle Image Velocimetry (PIV) measurements were carried out in an optically accessible injection vessel at ambient temperature and pressure. Two different fuels were used: commercial gasoline and pure n-butanol. The fuel were injected at two different injection pressures: 5 MPa and 10 MPa. The effect of n-butanol using on the liquid spray morphology, tip penetration, cone angle and velocity vector distribution of the liquid fuel droplets was explored.
2015-04-14
Technical Paper
2015-01-0941
Gina M. Magnotti, Caroline L. Genzale
Spray processes, such as primary breakup, play an important role for subsequent combustion processes and emissions formation. Accurate modeling of these spray physics is therefore key to ensure faithful representation of both the global and local characteristics of the experimentally measured spray. However, the physical mechanism underlying primary breakup in fuel sprays is still not known. Several theories have been proposed, the most widely used being aerodynamic-induced breakup or liquid turbulence-induced breakup. There is therefore a need to assess the appropriateness of each of these breakup theories and compare the predicted spray morphologies over a wide range of conditions relevant to engine operation. Failure to adequately validate the physical basis of spray models can compromise their predictive capabilities in engine and spray combustion simulations.
2015-04-14
Technical Paper
2015-01-0949
Mathis Bode, Tobias Falkenstein, Vincent Le Chenadec, Seongwon Kang, Heinz Pitsch, Toshiyuki Arima, Hiroyoshi Taniguchi
Compared to conventional injection techniques, Gasoline Direct Injection (GDI) has a lot of advantages such as increased fuel efficiency, high power output and emissions levels, which can be more accurately controlled. Therefore, this technique is one of the major topics of today's injection system research. The performance of GDI systems depends on multiple physical processes. The internal flow and the mixing of the coherent liquid stream with the gaseous ambient environment are two examples. Studying these processes is very difficult due to the overall complexity and the involved small length and time scales. Especially the region just after exiting the nozzle, where the primary breakup occurs, is experimentally hardly accessible, but a clear understanding of this region is particularly important, because primary breakup affects multiple other physical processes.
2015-04-14
Technical Paper
2015-01-0893
Michael D. Kass, Chris Janke, Raynella Connatser, Sam Lewis, James keiser, Timothy Theiss
Plastic materials are used ubiquitously in fuel infrastructure systems. A matrix of plastic specimens including thermoplastics and thermosetting resins were exposed to No. 2 diesel fuel and a blend containing 20% bio-oil. Material types included permeation barriers, (PET, PPS, PVDF, and PTFE), Nylon, acetals, polyethylene and several types of fiberglass resin, Four specimens were evaluated for each material type (three immersed in the test fuel liquid and one placed exposed to the vapor phase only). The exposure time for each material was 16 weeks at 60oC For each specimen exposed to the liquid fuel, the mass and volume change and hardness were measured for both wetted and dried conditions. The specimens exposed to the vapor phase were measured for hardness only. Dynamic mechanical analysis was also performed for each material to determine the onset of the glass to rubber transition temperature.
2015-04-14
Technical Paper
2015-01-0911
Juliane Wetzel, Michael Henn, Mark Gotthardt, Hermann Rottengruber
The optimization of the mixture formation represents a great potential for the decrease of fuel consumption and emissions of the spark-ignition engine. The injector and the nozzle have the main influence in this case. In order to adjust the nozzle geometry according to the requirements an understanding of the physical transactions in the fuel spray is indispensable. In particular the primary spray break-up is still inadequately described due to the difficult accessibility with optical measuring instruments. This paper presents a methodology for the characterization of the nozzle-near spray development, which substantially influences the entire spray shape. Single hole injectors of the gasoline direct injection (GDi) with different nozzle hole geometries were investigated at a high pressure chamber by using the MIE scattering technique. To magnify the spray very close to the nozzle exit a long-distance microscope in combination with a Nd:YAG-laser were used.
2015-04-14
Technical Paper
2015-01-0926
Tianyun Li, Min Xu, David Hung, Shengqi Wu, Siqi Cheng
Comparing with port-fuel-injection (PFI) engine, the fuel sprays in spark-ignition direct-injection (SIDI) engines play more important roles since they significantly influence the combustion stability, engine efficiency as well as emission formations. In order to design higher efficiency and cleaner engines, further research is needed to understand and optimize the fuel spray atomization and vaporization. This paper investigates the atomization and evaporation of ethanol and gasoline sprays under realistic SIDI engine conditions. An optical diagnostic technique combining high-speed Mie scattering and Schlieren imaging has been applied to study the liquid and vapor fuel distributions inside a constant volume chamber under various operating conditions. The effects of ambient temperature and pressure, fuel temperature, and fuel type on spray atomization and vaporization are analyzed by quantitative comparisons of spray characteristics.
2015-04-14
Technical Paper
2015-01-0935
Leonid Tartakovsky, Ran Amiel, Vladimir Baibikov, Mark Veinblat
It is known that in spark ignition (SI) engines with external mixture formation (carburetor, single-point- and port fuel injection) that are widely used in various non-automotive applications a certain part of injected fuel impinges internal surfaces of the intake manifold. This part of the fuel deposits on the manifold surface in the form of a liquid film, which is crawling to cylinders at substantial lower velocity than the main air/fuel mixture stream. Quantity of this liquid fuel penetrating into the individual cylinders differs depending on their location. It is greater for the cylinders located nearer to the port and lesser for the distant cylinders. Any change in operating regime or ambient temperature results in a change of the wall film thickness.
2015-04-14
Technical Paper
2015-01-0919
Timothy H. Lee, Yilu Lin, Han Wu, Lei Meng, Alan Hansen, Chia-Fon Lee
Recent research had shown that butanol, which has a more similar property with current transportation fuel than ethanol, has the potential of being more suitable to use as a blend in diesel engines. However, the main obstacle is the high cost of butanol production process. Acetone-butanol-ethanol (ABE) is an intermediate product during the fermentation process of butanol production. By eliminating the further separation and purification process, using ABE directly in diesel blends has the potential of greatly decreasing the overall cost for fuel production, which would further lead to a vast commercial use of ABE-diesel blend on market. Many researches had been done in the past five years concerning spray and combustion processes of both neat ABE and ABE-diesel mixture. Also, different compositions of ABE mixture had been characterized with the similar experimental approach.
2015-04-14
Technical Paper
2015-01-0796
Stephen Busch, Kan Zha, Paul C. Miles, Alok Warey, Francesco Pesce, Richard Peterson, Alberto Vassallo
Various pilot-main injection strategies are investigated for a part-load operating point in a single cylinder optical Diesel engine. With a pilot injection energizing signal that is advanced from the main injection by 300 µs or more, a 9 dB reduction in combustion noise is achieved. It is observed that as the energizing dwell between a single pilot and the main injection is decreased below 200 µs, combustion noise passes through a minimum and a further reduction of 3 dB is possible. This additional decrease in combustion noise is not associated with increases in smoke or NOx emissions. The injection schedules employed in the engine are analyzed with a hydraulic injection analyzer to provide rate shapes for each of the dwells tested. Two distinct injection events are observed even at the shortest dwell tested, and various rate shaping effects are observed with the main injection event as the dwell is adjusted.
2015-04-14
Technical Paper
2015-01-0946
Yongjin Jung, Julien Manin, Scott Skeen, Lyle M Pickett
A variation in spreading angle of diesel spray from a 3-hole nozzle injector was seen by a long distance microscopy in non-reacting and non-evaporating conditions. The variation from an axial single-hole injector with a nominally identical nozzle size does not occurred in non-reacting or reacting conditions. To investigate the effect of the variation in the spreading angle, liquid penetration length were measured by the Mie scattering in a horizontal configuration to avoid a temperature gradient within the combustion vessel. In addition, the diffused back illumination (DBI) was applied to the vertically injected configuration after matching an ignition delay in both configurations to be similar. Schlieren was employed to quantity the penetration and the spreading angle of vapor jet. The liquid penetration increased gradually after a rapid ramp-up region and starts a hump at around 600 us, which corresponds to the convergence of the spreading angle.
2015-04-14
Technical Paper
2015-01-1264
Junseok Chang, Yoann Viollet, Abdullah Alzubail, Amir Faizal Naidu Abdul-Manan, Abdullah Al Arfaj
This paper explores the potential for reducing transport-related greenhouse gas (GHG) emissions by introducing high-efficiency spark-ignition engines with a dual-fuel injection system to customize octane of the fuels based on real-time engine requirements. Recent study [1] shows that 4-6% GHG emissions can be reduced by replacing 2/3 light duty vehicle fleet with high efficiency engines that are designed with higher compression ratio and boost levels. However, this can be only possible if premium gasoline fuel (Research Octane Number, RON=98 or 100) is readily available on a large scale to supply a fleet demand. From a refinery perspective, increasing the octane of the fuels to such high levels could potentially require significant and costly upgrades to the reforming and isomerization units as well as lower gasoline yield, and thus, this is not an economically attractive option for many of the refiners. In our study, we considered different strategy.
2015-04-14
Technical Paper
2015-01-0861
Matthew Younkins, Margaret S. Wooldridge, Brad A. Boyer
Hydrogen fueled internal combustion engines have potential for high thermal efficiencies; however, high efficiency conditions can produce high nitrogen oxide emissions (NOx) that are challenging to treat using conventional 3-way catalysts. This work presents the results of an experimental study to reduce NOx emissions while retaining high thermal efficiencies in a single-cylinder research engine fueled with hydrogen. Specifically, the effects on engine performance of the injection of water into the intake air charge were explored. The hydrogen fuel was injected into the cylinder directly. Several parameters were varied during the study, including the amount of water injected into the intake charge, the amount of fuel injected, the phasing of the fuel injection, the number of fuel injection events, and the ignition timing. The results were compared with expectations for a conventionally operated hydrogen engine where load was controlled through changes in equivalence ratio.
2015-04-14
Technical Paper
2015-01-0933
Jaclyn Johnson, Jeffrey Naber, Meng Tang, Zachary Taylor, Kyle Yeakle, Eric Kurtz, Nan Robarge
Diesel combustion and emissions is largely spray and mixing controlled. Spray and combustion models enable studies of spray and combustion over a range of conditions to understand optimum combustion strategies. The validity of these models depends on the inputs, including the rate of injection profile of the injector. One method to measure the rate of injection is using the momentum flux method where the injected fuel spray is directed onto a force transducer which provides measurements of momentum flux, from which mass flow rate can be determined. The usefulness of the spray model is dictated by the accuracy of the momentum flux measurement. In this study, the impact of impingement distance (the distance from injector nozzle to the anvil connected to the force transducer) is characterized over a range of 2 – 12 mm.
2015-04-14
Technical Paper
2015-01-0913
Ryo Uchida, Shinya Okamoto, Daisuke Tanaka, Keiji Ozawa, Tsuneaki Ishima, Toru Noda
In a direct injection gasoline engine, the impingement of injected fuel on the oil film, i.e. cylinder liner gives rise to various problems such as abnormal combustion, oil dilution and particulate matter emission. Therefore, in order to solve these problems, it is necessary to have a clear understanding of the impingement behavior of the fuel spray onto the oil film. However, there is little information on the impingement behavior of the fuel droplet onto the oil film, whereas many investigations on the impingement behavior of the fuel droplet onto the fuel film are reported. In this study, fundamental investigations were performed for the purpose of clarifying the impingement behavior of the fuel spray onto the oil film. A single fuel droplet mixed with fluorescence dye was dripped on the oil film. To separately measure the fuel and the oil after impingement, simultaneous Mie scattering and laser-induced fluorescence (LIF) methods were performed.
2015-04-14
Technical Paper
2015-01-0931
Zihan Wang, Andrew Swantek, Riccardo Scarcelli, Daniel Duke, Alan Kastengren, Christopher F. Powell, Sibendu Som, Ronald Reese, Kevin Freeman, York Zhu
This paper focuses on detailed numerical simulations of direct injection diesel and gasoline sprays from production grade, multi-hole injectors. In a dual-fuel engine the direct injection of both the fuels can facilitate appropriate mixture preparation prior to ignition and combustion. Diesel and gasoline sprays are simulated using high-fidelity Large Eddy Simulations (LES) with the dynamic structure sub-grid scale model. Numerical predictions of liquid penetration, fuel density distribution as well as transverse integrated mass (TIM) at different axial locations versus time are compared against x-ray radiography data obtained from Argonne National Laboratory. A necessary, but often overlooked, criterion of grid-convergence is ensured by using Adaptive Mesh Refinement (AMR) for both diesel and gasoline. Nine different realizations are simulated and the effects of random seeds on spray behavior are investigated.
2015-04-14
Technical Paper
2015-01-0915
Ehsan Faghani, Patrick Kirchen, Steven N. Rogak
In direct-injection engines, combustion and emission formation is strongly affected by injection quality. Injection quality is related to mass-flow rate shape, momentum rate shape, stability of pulses as well as mechanical and hydraulic delays associated with fuel injection. Finding these injector characteristics aids the interpretation of engine experiments and design of new injection strategies. The goal of this study is to investigate the rate of momentum for the single and post injections for high-pressure direct-injection natural gas injectors. The momentum measurement method has been used before to study momentum rate of injection for single and split injections for diesel sprays. In this paper, a method of momentum measurement for gas injections is developed in order to present transient momentum rate shape during injection timing. In this method, a gas jet impinges perpendicularly on a pressure transducer surface.
2015-04-14
Technical Paper
2015-01-0938
Prashanth Karra, Thomas Rogers, Petros Lappas
The air entrainment process of a compressed natural gas transient fuel jet was investigated in a constant-volume chamber using Schlieren and particle image velocimetry (PIV) techniques. Jet to ambient pressure ratios of 20, 40, and 60 were tested. In each test, nitrogen was used to fill the chamber as an air surrogate before the jet of natural gas was injected. Schlieren high speed videography and PIV experiments were performed at the same conditions. Schlieren mask images were used to accurately identify the jet boundary which was then superimposed onto a PIV image. Vectors adjacent to the Schlieren mask in the PIV image were used to calculate the spatial distribution of the air entrainment at the jet boundary. The effects of ambient density and injection pressure on the air entrainment and contour shape at various parts of the jet are investigated.
2015-04-14
Technical Paper
2015-01-0917
Alessandro Montanaro, Michela Costa, Ugo Sorge, Luigi Allocca
The work analyses, from both the experimental and the numerical point of view, the interaction of a spray generated from an injector for GDI applications with a solid wall. In GDI mixture formation, a relevant quantity of the injected gasoline may unintentionally impact on the combustion chamber walls, or be intentionally directed towards the piston head to redirect the spray towards the spark plug, as in the wall-guided configuration. Spray droplets may hit on the surface and being rebounded, stick to form a film or being heated and undergo secondary evaporation. The deposited fuel on the wall evaporates more slowly than free droplets and does not permit a sufficient homogeneity of the mixture prior of the start of the ignition. The deposition of a gasoline film on the chamber walls, indeed, is a relevant source of pollutants production like unburned hydrocarbon and particulate matter.
2015-04-14
Technical Paper
2015-01-1163
Gabriel Elias, Stephen Samuel, Alessandro Picarelli
This study details the investigation into the hybridization of engine ancillary systems for 2014+ Le Mans LMP1-H vehicles. This was conducted in order to counteract the new strict fuel-limiting requirements governing the powertrain system employed in this type of vehicles. Dymola 1D vehicle simulation software was used to construct a rectilinear vehicle model with complete ancillary system, and a map based 3.8L, V8, engine and its associated ancillary systems, including oil pumps, water pump and fuel pump and a powertrain system with a full kinetic energy recovery system (KERS) strategy. Appropriate validation strategy was implemented to validate the model. A validated model was used to study the difference in fuel consumption for the conventional ancillary drive off of the internal combustion engine in various situational tests and a hybrid-electric drive for driving engine ancillaries.
2015-04-14
Technical Paper
2015-01-0918
Daniel Duke, Andrew Swantek, Alan Kastengren, Kamel Fezzaa, Christopher Powell
Cavitation plays an important role in fuel injection systems. It alters the nozzle’s internal flow structure and discharge coefficient, and also contributes to injector wear. Quantitatively measuring and mapping the cavitation vapor distribution in a fuel injector is difficult, as cavitation occurs on very short time and length scales. Optical measurements of transparent model nozzles can indicate the morphology of large-scale cavitation, but are generally limited by the substantial amount of scattering that occurs due to large changes in refractive index between vapor and liquid phases. These limitations can be overcome with x-ray diagnostics, as x-rays refract, scatter and absorb much more weakly. Here, we present an overview of some recent developments in quantitative x-ray diagnostics for cavitating flows. Measurements were conducted at the Advanced Photon Source at Argonne National Laboratory, using a submerged plastic test nozzle 500µm in diameter.
2015-04-14
Technical Paper
2015-01-0921
Raul Payri, Jaime Gimeno, Pedro Marti-Aldaravi, Marcos Carreres
Proper initial conditions are essential to successfully perform a simulation, specially for highly transient problems such Diesel spray injection. Until now, no much attention has been paid to the internal nozzle flow initialization because spray simulations are usually decoupled from the nozzle. However, new homogeneous models, such Eulerian Spray Atomization (ESA) model, allow simulating the internal nozzle flow and the spray seamlessly. Therefore, behavior of the spray for the first microseconds is highly influenced by the initial conditions inside the nozzle. Furthermore, last experiments confirm the presence of gas inside the nozzle between following injections. This work deals with the initilialization procedure in a way that mass flow rate, momentum flux and spray penetration curves are well predicted by the model.
2015-04-14
Technical Paper
2015-01-0934
Pascal Tetrault, Etienne Plamondon, Matthieu Breuze, Camille Hespel, Christine Mounaïm-Rousselle, Patrice Seers
Many diesel fuel spray models have been proposed in the literature. In some instance, they are based on experimental correlations such as (Pastor et al., 2011) who proposed a correlation based on a statistical analysis of Fischer-Tropsch and biodiesel experimental fuels spray under evaporating conditions and found that the liquid length of the spray was sensitive to the fuel boiling range and highly sensitive to the ambient temperature. Other models are based on physical principles such as the one proposed by (Desantes et al., 2006) who presented a fuel spray tip penetration model based on the measurements of momentum flux that they successfully compared against experimental data. While some models are useful only during the injector needle opening or for very long injection, (Roisman, Araneo et Tropea, 2007) analyzed the tip of the spray and proposed a two regions model based on the early stage of the spray and the far field penetration.
2015-04-14
Technical Paper
2015-01-0939
Daliang Jing, Shi-Jin Shuai, Zhi Wang, Yanfei Li, Hongming Xu
With the increasing demand of energy conservation and environmental protection, further improvement of fuel efficiency and emission reduction in internal combustion engines are urgently required due to the limited energy reserves, rising price of crude oil and climate change. Gasoline direct injection (GDI) engine plays an important part in this area and has experienced a rapid development during the last decade. The design and optimization of a modern spray-guided GDI engine requires a thorough understanding of the fuel sprays characteristics and atomization process. The fuel spray Computational Fluid Dynamics (CFD) modeling technology can be an effective means to study and predict spray characteristics, and as a consequence, to drastically reduce experimental work during the engine development process. For this reason, an accurate numerical simulation of the spray evolution process is imperative.
2015-04-14
Technical Paper
2015-01-0943
Bizhan Befrui, Mario D'Onofrio, Lee E. Markle, Peter Spiekermann
Abstract: The spray primary breakup is an important intermediate stage in the spray atomization process: it represents the primary disintegration of the liquid jet issuing from the nozzle as a result of the specific velocity, turbulence and vorticity conditions imparted onto it by the seat-nozzle geometry. It also represents a major area of shortcoming in the current Lagrangian methods for spray analysis, since the process is represented by semi-empirical models that cannot be directly verified against experimental data, due to difficulty of spray characterization in the optically-dense near-nozzle region. The VOF-LES simulation of the injector nozzle flow and jet primary breakup affords the potential for analysis of the complex influence of the seat-nozzle flow and the jet primary breakup process.
2015-04-14
Technical Paper
2015-01-0948
Le (Emma) Zhao, Ahmed Abdul Moiz, Jeffrey Naber, Seong-Young Lee, Sam Barros, William Atkinson
Liquid spray breakup and atomization, two multi-phase phenomena, strongly affect the ignition and combustion processes. High-speed jet-to-jet impingement in water sprays could be an effective phenomenon for the spray propagation and droplet vaporization. To achieve higher vaporization efficiency, impingement from two-hole nozzles is analyzed in this paper. This paper focuses on investigating vaporization mechanism as a function of the impingement location and the collision breakup process provided by two-hole impinging jet nozzles. CFD (Computational Fluid Dynamics) is adopted to do simulation. Lagrangian model is used to predict jet-to-jet impingement and droplet breakup conditions while KH-RT breakup and O’Rourke collision models are implemented for the simulation.
2015-04-14
Technical Paper
2015-01-0883
Yoshihiro Imaoka, Kiyotaka Shouji, Takao Inoue, Toru Noda
Technologies for improving the fuel economy of gasoline engines have been vigorously developed in recent years for the purpose of reducing CO2 emissions. Increasing the compression ratio for improving thermal efficiency and downsizing the engine based on fuel-efficient operating conditions are good examples of technologies for enhancing gasoline engine fuel economy. A direct-injection system is adopted for most of these engines. Direct injection can prevent knocking by lowering the temperature through fuel evaporation in the cylinder. Therefore, direct injection is highly compatible with downsized engines that frequently operate under severe supercharging conditions for improving fuel economy as well as with high compression ratio engines for which susceptibility to knocking is a disadvantage. On the other hand, direct-injection engines have certain issues such as the need to reduce particulate matter (PM) emissions, and technical measures must be developed for that purpose.
2015-04-14
Technical Paper
2015-01-0795
Chad Koci, Glen Martin, Tim Bazyn, Wayne Morrison, Kenth Svensson, Christopher Gehrke
Driven by experimental observations of varying diesel Lift-Off-Length (LOL) recession behavior at End of Injection (EOI), the effect of the shape of the EOI was investigated in order to improve the understanding of the last portion of the traditional diesel diffusion combustion process. Here, the LOL recession at EOI is when the LOL of a mixing controlled diesel jet recedes backwards toward the fuel injector nozzle orifice. The fuel injection rate shape, specifically focusing on varying EOI behavior, was substantially varied via unique experimental fuel injection hardware and studied with momentum rate measurements and optical combustion spray chamber imaging. Rate shapes were varied through fuel pressure modulation, not injector flow area modulation or control needle throttling. Three levels of EOI rates, two ambient temperatures, and two ambient densities, were used in the combusting spray chamber experiments.
2015-04-14
Technical Paper
2015-01-0950
Jonas Galle, Roel Verschaeren, Sebastian Verhelst
The need for simulation tools for the internal combustion engine is becoming more and more important due to the complex engine design and increasingly strict emission regulation. This implies models that are able to give more accurate results while keeping the time efforts for calculations at an acceptable level. Fuels consist of a complex mixture of different molecules which cannot realistically be handled in computations. Simplifications are required and are realized using fuel surrogates. The main goal of this work is to show that the choice of the surrogates is of importance if simplified models are used and that the performance strongly depends upon the sensitivity of the fuel properties that refer to the main model hypotheses. This is important as this is usually not taken into consideration by modelers. As a consequence of these influences, too much tuning needs to be done to match experiments with the modeling.
2015-04-14
Technical Paper
2015-01-0870
Gabriel Ingesson, Lianhao Yin, Rolf Johansson, Per Tunestal
Gabriel Ingesson, Yin Lianhao, Rolf Johansson, Per Tunestål August 30, 2014 Abstract The combustion timing in internal combustion engines aects fuel consumption, in cylinder peak pressure, engine noise and emission levels. The combination of an in cylinder pressure sensor together with a direct injection fuel system lends itself well for cycle to cycle control of the combustion timing. This paper presents a method of controlling combustion timing by the use of a cycle to cycle injection timing algorithm. At each cycle the current estimated rate of heat release is used to predict the in cylinder pressure changes due to a combustion timing shift. The prediction is then used to obtain a cycle to cycle model that relates combustion timing to indicated mean effective pressure, max pressure and max pressure derivative. Injection timing is then decided by solving an optimization problem involving the obtained model.
2015-04-14
Technical Paper
2015-01-0831
Wonah Park, Youngchul Ra, Eric Kurtz, Werner Willems, Rolf D. Reitz
The low temperature combustion concept is very attractive for reducing NOx and soot emissions in diesel engines. However, it has potential limitations due to higher combustion noise and CO and HC emissions. A multiple injection strategy is an effective way to reduce unburned emissions and noise in LTC. In this paper, the effect of multiple injection strategies was investigated to reduce combustion noise and unburned emissions in LTC conditions. A hybrid surrogate fuel model was developed and validated, and was used to improve LTC predictions. Triple injection strategies were considered to find the role of each pulse and then optimized. The split ratio of the 1st and 2nd pulses fuel was found to determine the ignition delay. Increasing mass of the 1st pulse reduced unburned emissions and an increase of the 3rd pulse fuel amount reduced noise. It is concluded that the pulse split ratio can be used as a control factor for emissions and noise.
Viewing 1 to 30 of 5811