scholarly journals COMBUSTION ANALYSIS OF HCCI ENGINE AT DIFFERENT OPERATING CONDITIONS

2021 ◽  
Author(s):  
CHANDRASEKHARYADAV Y ◽  
◽  
Dr. SREEKANTH D.V ◽  
Dr. SAURAV DAS ◽  
◽  
...  
Keyword(s):  
Working Conditions ◽  
Soot Formation ◽  
Direct Injection ◽  
Flow Simulation ◽  
Simulation Software ◽  
Operating Conditions ◽  
Phase System ◽  
Ic Engine ◽  
Cold Flow ◽  
Hcci Engine

Automobile pollution is causing a huge trouble worldwide and there is an urgent need to reduce it. Researches are being carried out for ways of reducing automobile pollution. The most common tool for converting liquid and gas fuel into useful mechanical work is the internal combustion (IC) engine. The explanation for its well-accepted efficiency, economics, longevity, controllability and other competitive alternatives can be explained by its general appearance. NOx and soot formation are due to the heterogeneous non-premixed combustion of high local temperatures and the local oxygen shortage in the traditional direct injection diesel powered engine. The adjustment to the combustion cycle to boost engine output is an alternative to rising engine efficiency and reducing engine emissions. A simulation software with CFD code was implemented in this context. The cold flow of the working conditions for HCCI engine control by creating a comprehensive model. Furthermore, the use of the in-cylinder model potential for cold flow simulation in the SI engine has been demonstrated. All strokes are replicated, pulling, compressing, expansion and exhaust. The Discrete Phase System is used for injecting, evaporating and boiling water, where the simulation depicts the working conditions of the engine for unravelling the flow physics taking place.

Development of a Two-Dimensional Streamline Curvature Code

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Ioannis Templalexis ◽  
Pericles Pilidis ◽  
Vassilios Pachidis ◽  
Petros Kotsiopoulos
Keyword(s):  
Flow Simulation ◽  
Two Dimensions ◽  
Simulation Software ◽  
Design Tool ◽  
Operating Conditions ◽  
Teaching Tool ◽  
Two Dimensional ◽  
Streamline Curvature ◽  
Cascade Models ◽  
Inlet Conditions

Two-dimensional (2D) compressor flow simulation software has always been a very valuable tool in compressor preliminary design studies, as well as in compressor performance assessment operating under uniform and non-uniform inlet conditions. This type of software can also be used as a supplementary teaching tool. In this context, a new streamline curvature (SLC) software has been developed capable of analyzing the flow inside a compressor in two dimensions. The software was developed to provide great flexibility, in the sense that it can be used as: (a) a performance prediction tool for compressors of a known design, (b) a development tool to assess the changes in performance of a known compressor after implementing small geometrical changes, (c) a design tool to verify and refine the outcome of a preliminary compressor design analysis, and (d) a teaching tool to provide the student with an insight of the 2D flow field inside a compressor and how this could be effectively predicted using the SLC method combined with various algorithms and cascade models. Apart from describing in detail the design, structure, and execution of the SLC software, this paper also stresses the importance of developing robust, well thought-out software and highlights the main areas a potential programmer should focus on in order to achieve this. This text also highlights the programming features incorporated into the development of the software in order to make it amenable for teaching purposes. The paper reviews in detail the set of cascade models incorporated for subsonic and supersonic flow, for design and off-design operating conditions. Moreover, the methods used for the prediction of surge and choke are discussed in detail. The code has been validated against experimental results, which are presented in this paper together with the strong and weak points of this first version of the software and the potential for future development. Finally, an indicative case study is presented in which the shift of streamlines and radial velocity profiles is demonstrated under the influence of two sets of compressor inlet boundary conditions.

scholarly journals Impact of the Primary Break-Up Strategy on the Morphology of GDI Sprays in 3D-CFD Simulations of Multi-Hole Injectors

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2890 ◽  
Author(s):  
Sparacino ◽  
Berni ◽  
d’Adamo ◽  
Krastev ◽  
Cavicchi ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Direct Injection ◽  
Flow Simulation ◽  
Back Pressure ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
Ambient Conditions ◽  
Phase Doppler Anemometry ◽  
Break Up ◽  
Primary Break

The scientific literature focusing on the numerical simulation of fuel sprays is rich in atomization and secondary break-up models. However, it is well known that the predictive capability of even the most diffused models is affected by the combination of injection parameters and operating conditions, especially backpressure. In this paper, an alternative atomization strategy is proposed for the 3D-Computational Fluid Dynamics (CFD) simulation of Gasoline Direct Injection (GDI) sprays, aiming at extending simulation predictive capabilities over a wider range of operating conditions. In particular, attention is focused on the effects of back pressure, which has a remarkable impact on both the morphology and the sizing of GDI sprays. 3D-CFD Lagrangian simulations of two different multi-hole injectors are presented. The first injector is a 5-hole GDI prototype unit operated at ambient conditions. The second one is the well-known Spray G, characterized by a higher back pressure (up to 0.6 MPa). Numerical results are compared against experiments in terms of liquid penetration and Phase Doppler Anemometry (PDA) data of droplet sizing/velocity and imaging. CFD results are demonstrated to be highly sensitive to spray vessel pressure, mainly because of the atomization strategy. The proposed alternative approach proves to strongly reduce such dependency. Moreover, in order to further validate the alternative primary break-up strategy adopted for the initialization of the droplets, an internal nozzle flow simulation is carried out on the Spray G injector, able to provide information on the characteristic diameter of the liquid column exiting from the nozzle.

scholarly journals Homogeneous Charge Compression Ignition Combustion: Challenges and Proposed Solutions

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Mohammad Izadi Najafabadi ◽  
Nuraini Abdul Aziz
Keyword(s):  
Homogeneous Charge Compression Ignition ◽  
Fuel Efficiency ◽  
Operating Conditions ◽  
Future Research ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Ic Engine ◽  
Hcci Engine ◽  
Wide Range ◽  
Homogeneous Charge

Engine and car manufacturers are experiencing the demand concerning fuel efficiency and low emissions from both consumers and governments. Homogeneous charge compression ignition (HCCI) is an alternative combustion technology that is cleaner and more efficient than the other types of combustion. Although the thermal efficiency andNOxemission of HCCI engine are greater in comparison with traditional engines, HCCI combustion has several main difficulties such as controlling of ignition timing, limited power output, and weak cold-start capability. In this study a literature review on HCCI engine has been performed and HCCI challenges and proposed solutions have been investigated from the point view ofIgnition Timingthat is the main problem of this engine. HCCI challenges are investigated by many IC engine researchers during the last decade, but practical solutions have not been presented for a fully HCCI engine. Some of the solutions are slow response time and some of them are technically difficult to implement. So it seems that fully HCCI engine needs more investigation to meet its mass-production and the future research and application should be considered as part of an effort to achieve low-temperature combustion in a wide range of operating conditions in an IC engine.

A numerical study on soot formation and oxidation for a direct injection diesel engine

2003 ◽  
Vol 217 (5) ◽  
pp. 403-413 ◽  
Author(s):  
N Sung ◽  
S Lee ◽  
H Kim ◽  
B Kim
Keyword(s):  
Diesel Engine ◽  
Combustion Temperature ◽  
Soot Formation ◽  
Direct Injection ◽  
Soot Oxidation ◽  
Operating Conditions ◽  
Injection Timing ◽  
Mixture Ratio ◽  
Soot Particles ◽  
Carbon Radicals

A numerical cycle model is developed to investigate the soot production in a direct injection (DI) diesel engine. The Surovikin and Fusco models for soot formation and the Nagle model for soot oxidation are used with the KIVA-3V code. In the Surovikin model, carbon radicals are produced from pyrolysis of fuel and soot particles grow through collisions with fuel molecules. In the Fusco model, the carbon radicals and acetylene are formed from pyrolysis of fuel. There, acetylene works for the growth of soot particles. From investigation of the e. ects of the operating conditions on soot formation and oxidation, it is found that soot formation is mainly governed by fuel concentration and combustion temperature and soot oxidation is more dependent on combustion temperature. The air-fuel ratio a. ects soot formation more than injection timing. For a stoichiometric mixture ratio, soot formation is increased because of the high combustion temperature.

scholarly journals A novel in-cylinder fuel reformation approach to control HCCI engine combustion on-set

2009 ◽  
Vol 138 (3) ◽  
pp. 37-48
Author(s):  
Gnanaprakash GNANAM ◽  
Dale HAGGITH ◽  
Andrzej SOBIESIAK
Keyword(s):  
Positive Impact ◽  
Direct Injection ◽  
Operating Conditions ◽  
Experimental Results ◽  
Coolant Temperature ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Hcci Engine ◽  
Hcci Combustion ◽  
Partial Load

Homogeneous Charge Compression Ignition (HCCI) engines have the potential to deliver high thermal efficiencies (when compared to spark ignition engines) coupled with ultra-low NOx emissions and Particulate Matter (PM) for partial-load operating regions. However, the inherent absence of Start of Combustion (SOC) or combustion on-set control has been a major obstacle for implementing this technology into production engines. In the present work, a new in-cylinder reformation strategy to control the on-set of combustion has been incorporated into a HCCI engine fuelled with lean ethanol/air mixtures. The objective of the in-cylinder reformation process is to generate hydrogen enriched gas (which includes other intermediate species) from ethanol reformation, which is then used to control the subsequent HCCI cycle combustion on-set. The experimental engine used for the study is a four-stroke, three cylinder In-Direct Injection (IDI) type compression ignition engine which was converted to single cylinder operation for HCCI combustion. A proto-type reformation chamber has been designed and fabricated with direct injection capabilities to examine the proposed in-cylinder reformation process. In order to clarify the effects of reformation products on HCCI combustion on-set, experiments were conducted with constant engine speed, initial charge temperature, and engine coolant temperature. The engine performance was evaluated based on cycle-resolved in-cylinder pressure measurements and regulated engine-out emissions. The experimental results demonstrate that the proposed in-cylinder reformation strategy is an effective method for controlling HCCI combustion on-set (SOC) and reduces the regulated engine-out emissions. Furthermore, the experimental results indicate that there is an optimal in-cylinder reformation fuelling percentage which will have a positive impact on regular HCCI combustion at given operating conditions.

Modelling for investigation of combustion and emission characteristics in a high-speed direct-injection diesel engine with light duty under various operating conditions

2008 ◽  
Vol 222 (11) ◽  
pp. 2159-2170 ◽  
Author(s):  
H J Kim ◽  
B W Ryu ◽  
C S Lee
Keyword(s):  
High Speed ◽  
Soot Formation ◽  
Numerical Study ◽  
Direct Injection ◽  
Operating Conditions ◽  
Injection System ◽  
Combustion Model ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Fuel Mass

A numerical study was conducted to investigate combustion and emission characteristics in a high-speed direct-injection engine with a common-rail injection system under various operating conditions. In order to analyse the combustion characteristics, several models were used in this study. They were the renormalization group k– ε model, the hybrid Kelvin—Helmholtz (wave) and the Rayleigh—Taylor model, the shell auto-ignition model, and the laminar and turbulent characteristic timescale combustion model. The prediction of exhaust emissions was conducted using nitrogen oxide NO x formation with an extended Zel'dovich mechanism and Hiroyasu soot formation with the Nagle—Strickland-Constable oxidation model respectively. Experimental combustion and emission characteristics were compared with calculated results under various operating conditions, such as injection timing, injection pressure, fuel mass, and engine speed. The calculated results show similar patterns to the experimental results in the cylinder pressure and the rate of heat release. In the emissions characteristics, NO x emission decreased as injection timing was retarded and the NO x and soot amounts increased with the increase in the injected fuel mass. The calculated soot trends for various injection timings showed different patterns from the experimental trends as the injection timing were retarded.

scholarly journals Hydrocarbon species in SI and HCCI engine using winter grade commercial gasoline

2020 ◽  
Vol 180 (1) ◽  
pp. 17-24
Author(s):  
Usama ELGHAWI ◽  
Ahmed MAYOUF ◽  
Athanasios TSOLAKIS
Keyword(s):  
Engine Speed ◽  
Direct Injection ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
Hydrocarbon Emissions ◽  
Engine Exhaust ◽  
Engine Operation ◽  
Hcci Engine ◽  
Hydrocarbon Analysis ◽  
Commercial Gasoline

The study provides a qualitative and quantitative analysis of the C5-C11 hydrocarbon species generated in Spark Ignition – Homogeneous Charge Compression Ignition (SI/HCCI) gasoline direct injection (GDI) engine at range of operating conditions. The presented results and data were obtained from the combustion of winter grade commercial gasoline containing 2% w/w ethanol (C2H5OH) for the engine operated in steady-state, fully warmed-up condition. The hydrocarbon analysis in exhaust gases was executed on a Gas Chromatography-Mass Spectrometer (GC-MS) apparatus directly connected to the engine exhaust via heated line. The highest concentration of the total hydrocarbon emissions was obtained under low load HCCI engine operation at stoichiometric fuel-air ratio. The major hydrocarbon compounds detected in the collected samples were benzene, toluene, p-xylene, and naphthalene. Benzene originates from the incomplete combustion of toluene and other alkylbenzenes which are of considerable environmental interest. During the SI engine operation, increase of the engine speed and load resulted in the increase of benzene and the total olefinic species with simultaneous decrease in isopentane and isooctane. The same trends are seen with the engine operating under HCCI mode, but since the combustion temperature is always lower than SI mode under the same engine conditions, the oxidation of fuel paraffin in the former case was less. As a result, the total olefins and benzene levels in HCCI mode were lower than the corresponding amount observed in SI mode. Aromatic compounds (e.g., toluene), except for benzene, were produced at lower levels in the exhaust when the engine speed and load for both modes were increased.

Fundamental Study of Diesel-Piloted Natural Gas Direct Injection Under Different Operating Conditions

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Georg Fink ◽  
Michael Jud ◽  
Thomas Sattelmayer
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Soot Formation ◽  
Direct Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Gas Jet ◽  
Ignition And Combustion

Natural gas as an alternative fuel in engine applications substantially reduces both pollutant and greenhouse gas emissions. High pressure dual fuel (HPDF) direct injection of natural gas and diesel pilot has the potential to minimize methane slip from gas engines and increase the fuel flexibility, while retaining the high efficiency of a diesel engine. Speed and load variations as well as various strategies for emission reduction entail a wide range of different operating conditions. The influence of these operating conditions on the ignition and combustion process is investigated on a rapid compression expansion machine (RCEM). By combining simultaneous shadowgraphy (SG) and OH* imaging with heat release rate analysis, an improved understanding of the ignition and combustion process is established. At high temperatures and pressures, the reduced pilot ignition delay and lift-off length minimize the effect of natural gas jet entrainment on pilot mixture formation. A simple geometrical constraint was found to reflect the susceptibility for misfiring. At the same time, natural gas ignition is delayed by the early pilot ignition close to the injector tip. The shape of heat release is only marginally affected by the operating conditions and mainly determined by the degree of premixing at the time of gas jet ignition. Luminescence from the sooting natural gas flame is generally only detected after the flame extends across the whole gas jet at peak heat release rate. Termination of gas injection at this time was confirmed to effectively suppress soot formation, while a strongly sooting pilot seems to intensify soot formation within the natural gas jet.

Fundamental Study of Diesel-Piloted Natural Gas Direct Injection Under Different Operating Conditions

2018 ◽  
Author(s):  
Georg Fink ◽  
Michael Jud ◽  
Thomas Sattelmayer
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Soot Formation ◽  
Direct Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Gas Jet ◽  
Ignition And Combustion

Natural gas as an alternative fuel in engine applications substantially reduces both pollutant and greenhouse gas emissions. High pressure dual fuel direct injection of natural gas and Diesel pilot has the potential to minimize methane slip from gas engines and increase the fuel flexibility, while retaining the high efficiency of a Diesel engine. Speed and load variations as well as various strategies for emission reduction entail a wide range of different operating conditions. The influence of these operating conditions on the ignition and combustion process is investigated on a rapid compression expansion machine. By combining simultaneous Shadowgraphy and OH* imaging with heat release rate analysis, an improved understanding of the ignition and combustion process is established. At high temperatures and pressures the reduced pilot ignition delay and lift-off length minimize the effect of natural gas jet entrainment on pilot mixture formation. A simple geometrical constraint was found to reflect the susceptibility for misfiring. At the same time natural gas ignition is delayed by the early pilot ignition close to the injector tip. The shape of heat release is only marginally affected by the operating conditions and mainly determined by the degree of premixing at the time of gas jet ignition. Luminescence from the sooting natural gas flame is generally only detected after the flame extends across the whole gas jet at peak heat release rate. Termination of gas injection at this time was confirmed to effectively suppress soot formation, while a strongly sooting pilot seems to intensify soot formation within the natural gas jet.

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