Browse Topic: Stratified charge engines

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Improvements of Combustion and Emissions in a Natural Gas Fueled Engine with Hydrogen Enrichment and Optimized Injection Timings of the Diesel Fuel2022-32-009501/09/2022
In a natural gas fueled engine ignited by diesel fuel, the addition of hydrogen to the engine could be a possible way to improve thermal efficiency and reduce unburned methane which has a warming potential many times that of carbon dioxide as it promotes a more rapid and complete combustion. This study carried out engine experiments using a single cylinder engine with natural gas and hydrogen delivered separately into the intake pipe, and with pilot-injection of diesel fuel. The percentages of hydrogen in the natural gas-hydrogen mixtures were varied from 0% to 50% of the heat value. The results showed that the hydrogen addition has an insignificant effect on the ignition delay of the diesel fuel and that it shortens the combustion duration. The increase in the hydrogen ratio decreased the unburned hydrocarbon emissions more than the reduction of the amount of natural gas that was replaced by the hydrogen. Further, the direct injection timing of the diesel fuel was varied from early in
Kobashi, Yoshimitsu, Inagaki, Ryuya, Shibata, Gen, Ogawa, Hideyuki
Knock: A Century of Research03-15-01-000407/28/2021
Knock is one of the main limitations on increasing spark-ignition (SI) engine efficiency. This has been known for at least 100 years, and it is still the case today. Knock occurs when conditions ahead of the flame front in an SI engine result in one or more autoignition events in the end gas. The autoignition reaction rate is typically much higher than that of the flame-front propagation. This may lead to the creation of pressure waves in the combustion chamber and, hence, an undesirable noise that gives knock its name. The resulting increased mechanical and thermal loading on engine components may eventually lead to engine failure. Reducing the compression ratio lowers end-gas temperatures and pressures, reducing end-gas reactivity and, hence, mitigating knock. However, this has a detrimental effect on engine efficiency. Automotive companies must significantly reduce their fleet carbon dioxide (CO2) values in the coming years to meet targets resulting from the 2015 Paris Agreement
Corrigan, Daire James, Fontanesi, Stefano
Knock: A Century of Research03-15-01-0004-TEST-REC07/28/2021
Knock is one of the main limitations on increasing spark-ignition (SI) engine efficiency. This has been known for at least 100 years, and it is still the case today. Knock occurs when conditions ahead of the flame front in an SI engine result in one or more autoignition events in the end gas. The autoignition reaction rate is typically much higher than that of the flame-front propagation. This may lead to the creation of pressure waves in the combustion chamber and, hence, an undesirable noise that gives knock its name. The resulting increased mechanical and thermal loading on engine components may eventually lead to engine failure. Reducing the compression ratio lowers end-gas temperatures and pressures, reducing end-gas reactivity and, hence, mitigating knock. However, this has a detrimental effect on engine efficiency. Automotive companies must significantly reduce their fleet carbon dioxide (CO2) values in the coming years to meet targets resulting from the 2015 Paris Agreement
Corrigan, Daire James, Fontanesi, Stefano
Effect of a Split-Injection Strategy on the Atomisation Rate Using a High Pressure Gasoline DI Injector2020-01-032204/14/2020
The Gasoline direct-injection (GDI) engine can emit high levels of particulate matter and unburned Hydrocarbons when operating under stratified charge combustion mode. Injecting late in the compression stroke means the fuel has insufficient time to atomise and evaporate. This could cause fuel film accumulation on the piston surface and combustion liner. Locally fuel rich diffusion combustion could also result in the formation of soot particles. Employing a split-injection strategy can help tackle these issues. The first injection is initiated early in the intake stroke and could ensure a global homogeneous charge. The second injection during the compression stroke could help form a fuel-rich charge in the vicinity of the spark plug. Many studies have established the crucial role that a split-injection strategy plays in the stratified charge operation of GDI engines. The current study examines how a split-injection strategy affects the flow field and spray characteristics at high
Dhanji, Meghnaa Paresh, Zhao, Hua
Investigations on Pre-chamber Ignition Device Using Experimental and Numerical Approaches2019-01-216312/19/2019
Nowadays Spark Ignition (SI) engine efficiency is mainly limited by abnormal combustion (knock) and stability issues at high dilution rate (both EGR and air). Increasing the combustion velocity is a relevant way to overcome these limitations. Main strategy to increase the combustion velocity is to enhance the flow motion in the cylinder (tumble motion) in order to increase the turbulence during the combustion. Such approach is mainly performed by working on intake port design which lead to engine volumetric efficiency penalties. Another approach to increase the combustion velocities is to have multiple ignition kernels in the chamber. This can be obtained thanks to Turbulent Jet Ignition (TJI) which uses a pre-chamber to spread the initial flame kernel throughout the combustion chamber. To achieve pre-chamber optimization a deep understanding of the complex phenomena involved in TJI as well as validated numerical tools is required. The present paper aims at providing such understanding
Laget, O., Chevillard, S., Pilla, G., Gautrot, X., Colliou, T.
0D/1D Turbulent Combustion Model Assessment from an Ultra-Lean Spark Ignition Engine2019-01-140903/25/2019
This paper focuses on an assessment of predictive combustion model using a 0D/1D simulation tool under high load, different excess air ratio λ , and different combustion stabilities (based on coefficient of variation of indicated mean effective pressure COVimep). To consider that, crank angle resolved data of experimental pressure of 500 cycles are recorded under engine speed 1000 RPM and 2000 RPM, wide-open throttle, and λ=1.0, 1.42, 1.7, and 2.0. Firstly, model calibration is conducted using 18 cases at 2000 RPM using 500 cycle-averaged in-cylinder pressure to find optimized model constants. Then, the model constants are unchanged for other cases. Next, different cycle-averaged pressure data are used as inputs in the simulation based on the COVimep for studying sensitivity of the turbulent model constants. The simulation is conducted using 1D simulation software GT-Power. Firstly, a three-pressure analysis (TPA) model (intake, in-cylinder, exhaust) for experimental prediction and
Sok, Ratnak, Yamaguchi, Kyohei, Kusaka, Jin
Computational Fluid Dynamic Simulation of In-Cylinder Pressures to Validate High-Range VCR02-11-04-002010/22/2018
This article serves as a proof-of-concept and feasibility analysis regarding a variable compression ratio (VCR) engine design utilizing an exhaust valve opening during the compression stroke to vary the compression ratio instead of the traditional method of changing the cylinder or piston geometry patented by Ford, Mercedes-Benz, Nissan, Peugeot, Gomecsys, et al. [1]. In this concept, an additional exhaust valve opening was used to reduce the virtual compression ratio of the engine, without geometric changes. A computational fluid dynamics model in ANSYS Forte was used to simulate a single-cylinder, cold flow, four-stroke, direct injection engine cycle. In this model, the engine was simulated at a compression ratio of 10:1. Then, the model was modified to a compression ratio of 17:1. Then, an additional valve opening at the end of the compression stroke was added to the 17:1 high compression model. The valve opening at the end of the compression stroke was used to bleed off a small
Davis, Shelbie L., Washko, Frank
Combustion analysis in a SI engine with homogeneous and stratified pre-chamber system2018-36-011209/03/2018
Extensive studies of pre-chamber ignition systems in internal combustion engines have proven its effectiveness in reduction of fuel consumption and improvement in several combustion parameters. Considering the different types of pre-chamber configurations, this paper aims to compare the combustion in a SI engine with both homogeneous and stratified pre-chamber ignition systems. To achieve this objective a system with the ability to control the hydrogen injection in the pre-chamber was built. This system was installed in a multi-cylinder Ford Sigma 1.6L engine and tested in a dynamometric room. Tests consisted in imposing a constant rotation and IMEP to test three conditions: standard spark ignition, pre-chamber ignition system without fuel injection (homogenous) and with hydrogen injection (stratified). It was possible to identify that with the use of pre-chamber ignition system there is a reduction in specific fuel consumption and in the combustion duration. This phenomenon can be
Alvarez, Carlos Eduardo Castilla, Roso, Vinicius Rückert, Santos, Nathalia Duarte Souza Alvareng, Fernandes, Alysson Teixeira, Valle, Ramon Molina
Combustion Analysis of a Current Vehicular Engine Operating in Lean Air-Fuel Conditions2017-36-020711/07/2017
Environmental issues and energy security are critical concerns of the most countries. According researchers, excessive growth of land vehicles is one of the biggest contributors to global air pollution and oil reserves reduction. In this context, the use of lean burn technologies emerges as a promising strategy, allowing lower fuel consumption and pollutants emissions. Present work aims to analyze the behavior of a current commercial engine, gasoline fueled, varying the air-fuel ratio without the use of lean burn ignitions technologies. Analysis was performed through bench dynamometer tests, evaluating cylinder pressure, exhaust gas temperature, fuel conversion efficiency, cycle thermal efficiency, coefficient of variation in indicated mean effective pressure, apparent heat release rate, flame development angle and burn duration. As expected, mixture impoverishment caused a progressive increase of burn duration, flame development angle and coefficient of variation in indicated mean
Alvarez, Carlos Eduardo Castilla, Roso, Vinícius Rückert, Couto, Giselle Elias, Valle, Ramon Molina
Effect of Hydrogen Volume Ratio on the Combustion Characteristics of CNG-Diesel Dual-Fuel Engine2017-01-227010/08/2017
CNG-diesel dual fuel combustion mode has been regarded as a practical operation strategy because it not only can remain high thermal efficiency but also make full use of an alternative fuel, natural gas. However, it is suffering from misfire and high HC emissions under cold start and low load conditions. As known, hydrogen has high flammability. Thus, a certain proportion of hydrogen can be added in the natural gas (named HCNG) to improve combustion performance. In this work, the effect of hydrogen volume ratio on combustion characteristics was investigated on an optically accessible single-cylinder CNG-diesel engine using a Phantom v7.3 color camera. HCNG was compressed into the tank under different hydrogen volume ratios varied from 0% to 30%, while the energy substitution rate of` HCNG remained at 70%. The results show that with the increase of hydrogen volume ratios, the peak of in-cylinder pressure and heat release increase significantly, and the crank angles corresponding to the
Liu, Fushui, Kang, Yue, Wu, Han, Lee, Chia-Fon, Li, Yikai
Injector Fouling and Its Impact on Engine Emissions and Spray Characteristics in Gasoline Direct Injection Engines2017-01-080803/28/2017
In Gasoline Direct Injection engines, direct exposure of the injector to the flame can cause combustion products to accumulate on the nozzle, which can result in increased particulate emissions. This research observes the impact of injector fouling on particulate emissions and the associated injector spray pattern and shows how both can be reversed by utilising fuel detergency. For this purpose multi-hole injectors were deliberately fouled in a four-cylinder test engine with two different base fuels. During a four hour injector fouling cycle particulate numbers (PN) increased by up to two orders of magnitude. The drift could be reversed by switching to a fuel blend that contained a detergent additive. In addition, it was possible to completely avoid any PN increase, when the detergent containing fuel was used from the beginning of the test. Microscopy showed that increased injector fouling coincided with increased particulate emissions. Based on these results a selection of the
Henkel, Sebastian, Hardalupas, Yannis, Taylor, Alexander, Conifer, Christopher, Cracknell, Roger, Goh, Tor Kit, Reinicke, Paul-Benjamin, Sens, Marc, Rieß, Michael
Influence of Ethanol Content, Compression Ratio and Cylinder Head Material on Idling Speed, Warm-Up Time and Emissions of a Non-Road Small Single Cylinder Gasoline Engine2016-32-005511/08/2016
A Design of experiments methodology was carried out to investigate the effects of compression ratio, cylinder head material, and fuel composition on the engine speed, fuel consumption, warm-up time, and emissions of a carbureted single cylinder air-cooled spark ignited engine. The work presented here is aimed at finding out the sensitivity of engine responses, as well as the optimal combination among the aforementioned parameters. To accomplish this task two cylinder heads, one made of aluminum and the second one of cast iron, were manufactured; an antechamber-type adapter for the spark plug to modify the combustion chamber volume was used. Ethanol/gasoline blends containing 10 and 20 volume percent ethanol were prepared. Engine performance was evaluated based on the changes in engine speed at idle conditions. The concentrations of CO2, CO, and HC in the exhaust were recorded. The test results show that the higher engine speed, lower HC, and lower CO2 take place for the aluminum
Romero, Carlos Alberto, Mejia, Luz Adriana, Carranza, Yamid
Comparative Study of Unregulated Emissions on a Heavy Duty CNG Engine using CNG & Hydrogen Blended CNG as Fuels2016-01-809009/27/2016
One of the most promising solutions to address the twin problems of transport related pollution and energy security is to use alternative fuels. Compressed Natural gas (CNG) has been widely used in India to address the menace of pollution from commercial vehicles in cities like Delhi. Hydrogen blended compressed natural gas (HCNG) as a fuel has potential for further reducing harmful emissions and greenhouse gases. Enriching hydrogen in CNG improves combustion characteristic of CNG and reduces carbonyl emissions. Due to growing concerns over un-regulated emissions and their effect on human health, it is imperative to estimate un-regulated emissions from such alternatives for assessing overall impact of such fuels. Presently world over, emission legislations mainly addresses pollutants like CO, HC, NOx, CH4, NH3, PM etc. Relatively higher quantity in exhaust qualifies these pollutants to be monitored and controlled. But as the consumption of alternative fuels becomes comparable to that
Singh, Sauhard, Mishra, Sumit, Mathai, Reji, Sehgal, A K, Suresh, R
Automotive Direct-Injection Stratified-Charge Engine Development in the 1970-1980’s2016-01-017504/05/2016
Spark-ignition direct-injection technology existed since about 1930 for the primary purpose to give multifuel capability over what the compression-ignited diesel engine could provide. In subsequent decades development of multifuel engines continued both as higher-compression-ratio “spark-ignited diesel” and moderate-compressionratio stratified-charge engines. Global events in the 1960-1970’s, namely the oil embargo, oil-supply crises, and the passage of the U.S. Clean Air Act intensified interest in such engines. The military and large commercial fleet operators were particularly focused on efficiency and multifuel capability over concerns for fuel supplies. Automobile manufacturers were focused on gasoline-fueled efficiency and the potential to reduce engine-out legislated NOx emissions with the stratified-charged combustion systems. In this paper the major direct-injection spark-ignited stratified-charge concepts pursued during the 1970-1980’s are reviewed at a high level, and
Groff, Edward G.
Numerical Analysis of the Fluid Flow in a Prechamber for a Spark-ignition Engine2015-36-028909/22/2015
The use of torch ignition systems in spark-ignition engines represents an interesting option in the efforts to reduce pollutants emission and specific fuel consumption. Based on this idea, this paper presents a 3D model of a prechamber created for a spark-ignition engine and focuses on the numerical analysis of the fluid flow inside the modified chamber. This kind of analysis is very important once it allowed evaluating aspects like turbulence parameters, pressure inside the chamber and prechamber, fluid recirculation and a possible prechamber’s geometry for the engine. The studies were done in a four valve Single Cylinder Research Engine - SCRE. For the numerical modeling and fluid flow investigation it was used STAR-CD Software. The numerical results permitted to characterize the fluid flow in the modified engine and compare it with the standard engine, which showed significant differences and an interesting potential.
de Castro Radicchi, Fábio, Braga, Raphael Meireles, de Oliveira Alvarenga Coelho, Raniro, da Costa, Roberto Berlini Rodrigues, Valle, Ramón Molina
E100 Stratified Lean Combustion Analysis in a Wall-Air Guided Type GDI Optical Engine2015-36-026909/22/2015
Gasoline direct injection (GDI) engines have very attractive potential for improving fuel economy and exhaust emissions, especially disadvantages of increased fuel consumption at part load. In this research, a study has been made on the investigations of stratified lean combustion in a wall-air guided type spark-ignition single cylinder optical research engine. Experiments were conducted at constant load (NIMEP 3 bar) using ethanol as fuel, for a wide range of injection, ignition and mixture formation parameters. Engine efficiency and combustion stability were evaluated at each excess air ratio. Optical visualization illustrated the spray behavior and flame propagation. Specific fuel consumption improvement was achieved with lean burn mixtures. Thus, combustion analysis data based on in-cylinder pressure measurement provide useful data for ethanol GDI engine development.
da Costa, Roberto Berlini Rodrigues, Gomes, Carlos Alberto, Franco, Rafael Lara, Guzzo, Marcio Expedito, Pujatti, Fabrício José Pacheco
Development of a Quasi-Dimensional Spray Evaporation and Mixture Formation Model for Direct-Injection Spark-Ignition Engines2015-24-247109/06/2015
This paper presents a phenomenological quasi-dimensional model of the processes that lead to charge preparation in a Direct-Injection Spark-Ignition (DI-SI) engine, focusing on the physics of atomization and drop evaporation, spray development and the mutual interaction between these phenomena. Atomization and drop evaporation are addressed by means of constant-diameter drop parcels, which provide a discrete drop-size distribution. A discrete Probability Density Function (PDF) approach to fuel/air mixing is proposed, based on constant-mixture-fraction classes that interact with each other and with the drop parcels. The model has been developed in the LMS Imagine.Lab Amesim™ system simulation platform for multi-physical modeling and integrated in a generic SI combustion chamber submodel, CFM1D [15], of the IFP-Engine library. The validation of the approach is performed on an experimental test case consisting of a high pressure isooctane injection in a constant volume vessel for which
Pellegrino, Federico, Dulbecco, Alessio, Veynante, Denis
An Optical Analysis of a DISI Engine Cold Start-Up Strategy2015-01-187709/01/2015
Particulate number (PN) standards in the current ‘Euro 6’ European emissions standards pose a challenge for engine designers and calibrators during the warm-up phases of cold direct injection spark ignition (DISI) engines. To achieve catalyst light-off in the shortest time, engine strategies are often employed which inherently use more fuel to attain higher exhaust temperatures. This can lead to the generation of locally fuel-rich regions within the combustion chamber and the emission of particulates. This investigation analyses the combustion structures during the transient start-up phase of an optical DISI engine. High-speed, colour 9 kHz imaging was used to investigate five important operating points of an engine start-up strategy whilst simultaneously recording in-cylinder pressure. Results show a striking range of flame structures occurring at different times in the start-up cycle with significant differences in flame propagation rates, flame front structures and local air-fuel
Efthymiou, Petros, Garner, Colin P., Hargrave, Graham K., Richardson, David
A Study of Potential Fuel Economy Technologies to Achieve CAFE 2025 Regulations using Fleet Simulation Modeling Software2015-01-168304/14/2015
The 2025 Corporate Average Fleet Economy (CAFE) fuel economy regulations are a significant challenge to the automotive industry. These regulations require dramatic increases in vehicle fleet fuel economy. This paper will identify and analyze a portfolio of technologies that have the potential to achieve the 2025 CAFE fuel economy targets, focusing on powertrain enhancements. The study uses a MAHLE Powertrain developed fleet modeling tool and a range of vehicle technologies and powertrain data taken from MAHLE's global research and development activities. Powertrain technologies considered include extreme engine downsizing, dilute combustion, friction reduction, hybridization, diesel and alternative fuels. The vehicle technologies analyzed include vehicle light weighting, reduced rolling resistance, advanced transmissions and improved aerodynamics. The results of this study suggest that in order to meet CAFE 2025 fleet fuel economy regulations, a combination of advanced powertrain
Porter, Bernie, Blaxill, Hugh, Jariri, Noor
Study on Effect of Engine Operating Parameters on Flame Characteristics2015-01-074904/14/2015
In gasoline direct injection (GDI) engines, air-fuel mixture homogeneity plays a major role on engine performance, especially in combustion and emission characteristics. The performance of the engine largely depends on various engine operating parameters viz., start of injection, duration of injection and spark timing. In order to achieve faster results CFD is becoming a handy tool to optimize and understand the effect of these parameters. Therefore, this study aims on evaluating the two injection parameters viz., single and split injection to evaluate different flame characteristics. Novelty in this study is to define five different parameters which are called α, β, γ, δ and η the details of which are explained in the paper. In order to understand the flame characteristics, these five parameters are found to be very useful. In the present study, a single-cylinder, two-valve, four- stroke engine which is used in two-wheelers in India is considered for carrying out the CFD analysis. An
Sureshkumar, J., Venkitachalam, Ganesan, Mallikarjuna, J M, Elayaraja, R
Parametric Study and Secondary Circuit Model Calibration Using Spark Calorimeter Testing2015-01-077804/14/2015
The presented work describes how spark calorimeter testing was used for parametric study and secondary circuit model calibration. Tests were conducted at different pressures, sparkplug gaps and supplied primary energies. The conversion efficiency increases and the spark duration decreases when the gas pressure or the sparkplug gap size is increased. Both gas pressure and sparkplug gas size increase the positive column voltage which represents part of the electrical energy delivered to the gas. The opposite direction occurs when the supplied primary energy is increased. The testing results were then used to calibrate the secondary circuit model which consisted of the sparkplug, the sparkplug gap and the secondary wiring. A step-by-step method was used to calibrate the three constants of the model to match the calculated delivered energy with test data during arc / glow phase.
Abidin, Zainal, Chadwell, Christopher
Evaluation of Long Drain Gas Engine Oil on Heavy Duty Engine Using Hydrogen Blended CNG2015-01-096604/14/2015
The ever increasing demand of fuels for vehicles can only be met by use of alternate fuels like Compressed Natural Gas (CNG) and Hydrogen (H2). The 18 percent hydrogen enriched CNG fuel referred to as HCNG has the potential to lower emissions and is considered to be the first step towards promotion of a Hydrogen economy. While, automotive industry matures up with the usage of new engines, lubricant manufacturers are also moving on to the next stage by formulating oils to be used in gas engines such as CNG, HCNG etc. This paper presents the evaluation of gas engine oil on 6-cylinder heavy duty CNG engine using HCNG. The six cylinder engine was chosen due to its importance for urban bus transportation. The engine was optimized for using HCNG fuel. Initial performance of the engine using HCNG was compared vis-à-vis CNG and, thereafter, the engine was subjected to endurance test of 500 hours as per 8 mode engine simulated driving cycle. It has been observed that HCNG shows reduction of CO
Singh, Sauhard, Bhardwaj, Anil, Mathai, Reji, Sehgal, A K, Suresh, R, Das, B P, Tyagi, Nishant, Mohite, Jaywant, Chougule, N B
Injection Strategies, Optimization and Simulation Techniques on DI CNG Technology2015-26-004601/14/2015
CNG has long since been established as a front runner amongst other available alternative fuels. In India, its infrastructure and penetration far exceeds others. While other, more efficient alternatives are been researched, CNG has established itself in the market as the alternative fuel of choice for majority of Indians. CNG technology has evolved itself from the basic venturi system to the more efficient sequential injection system nowadays. While the efficiency of an engine using sequential injection CNG has increased, the inherent problem with respect to lower volumetric efficiency and hence less power still persists. Direct injection CNG technology is seen as the solution to this age old problem. In the older days, the lack of technological expertise in SI direct fuel injection provided a stumbling block for development of direct gas injection. But with the surge in technological advancement lately, especially in the gasoline direct injection area has opened new avenues for
Thipse, Sukrut S, Sonawane, Shailesh B, D' Souza, Ashwin F, Rairikar, S D, Kavathekar, Kishor Kumar, Marathe, Neelkanth V
Aerodynamic In-Cylinder Flow Simulation in an Internal Combustion Engine with Torch Ignition System2014-36-029809/30/2014
Stringent automotive emissions and fuel economy regulations have been bringing challenges for the development of new engine technologies to achieve greater levels of efficiency and pollutants reduction. In this scenario the homogeneous charge pre-chamber jet ignition system (HCJI) enables lean operation due the jet combustion gases emerging from the small pre-chamber combustor as the ignition source for main chamber combustion in an internal combustion engine. The present computational work was carrying out to investigate the interaction between the pre-chamber and main chamber fluid dynamics events. This CFD research was performed and validated with a experimental data for a single cylinder of a 4-stroke indirect fuel injection engine under the motoring condition running at 4500 rpm with 50% wide open throttle condition. The analyses are focused to identify the influences in the fluid flow field in the terms of tumble ratio and the turbulence kinetic energy along the degree of crank
BORGHI, F. T., MOREIRA, T. A. A., WHANCO, R., BARROS, J. E. M, VALLE, R. M.
Automotive Fuels Reference Book, Third EditionR-29703/05/2014
The first two editions of this title, published by SAE International in 1990 and 1995, have been best-selling definitive references for those needing technical information about automotive fuels. This long-awaited new edition has been thoroughly revised and updated, yet retains the original fundamental fuels information that readers find so useful. This book is written for those with an interest in or a need to understand automotive fuels. Because automotive fuels can no longer be developed in isolation from the engines that will convert the fuel into the power necessary to drive our automobiles, knowledge of automotive fuels will also be essential to those working with automotive engines. Small quantities of fuel additives increasingly play an important role in bridging the gap that often exists between fuel that can easily be produced and fuel that is needed by the ever-more sophisticated automotive engine. This book pulls together in a single, extensively referenced volume, the
Richards, Paul
CNG Fueling Strategies for Commercial Vehicles Engines-A Literature Review2013-01-281211/27/2013
The paper presents a survey of the opportunities to convert compression ignition heavy duty truck engines to work on single or dual fuel modes with CNG. In one popular option, the compression ignition engine is converted to spark ignition with throttle load control and port injection of the CNG. In another option of increasing popularity, the LNG is directly injected and ignited by direct injection of pilot Diesel. This latter option with direct injection of natural gas and diesel through separate injectors that are fully independent in their operation is determined to be the most promising, as it is expected to deliver better power density and similar part load fuel economy to Diesel.
Boretti, Alberto, Lappas, Petros, Zhang, Bingjie, Mazlan, Siti Khalijah
Advanced Glow Plug for Heavy Fuels Applications2013-01-171604/08/2013
With current DoD goals of switching to a common battlefield logistics fuel, there is a significant push to develop technologies that allow small, high-powered engines such as used in unmanned aerial, marine, and ground vehicles, typically fueled by volatile fuels such as gasoline, to operate on heavy fuels such as JP-8. In this paper, the feasibility of catalytic glow plugs as an enabling component for the use of heavy fuels both as a retrofit to existing engines as well as new engine designs is demonstrated. Compared to standard spark igniters and non-catalytic glow plugs, the use of catalytic glow plugs will provide benefits including lower required compression ratio, improved igniter life, reduced energy requirements, and overall reduction in system weight and size. The catalytic glow plugs were shown to have a significant increase in surface temperature (180+°C) with impingement of a fuel spray and this increase was maintained over many cycles of impingement. Engine testing
Baird, Benjamin, Etemad, Shahrokh
Laser Diagnostics and Optical Measurement Techniques in Internal Combustion EnginesR-40607/30/2012
The increasing concern about CO2 emissions and energy prices has led to new CO2 emission and fuel economy legislation being introduced in world regions served by the automotive industry. In response, automotive manufacturers and Tier-1 suppliers are developing a new generation of internal combustion (IC) engines with ultra-low emissions and high fuel efficiency. To further this development, a better understanding is needed of the combustion and pollutant formation processes in IC engines. As efficiency and emission abatement processes have reached points of diminishing returns, there is more of a need to make measurements inside the combustion chamber, where the combustion and pollutant formation processes take place. However, there is currently no good overview of how to make these measurements. Based on the author’s previous SAE book, Engine Combustion Instrumentation and Diagnostics, this book focuses on laser-based optical techniques for combustion flows and in-cylinder
Zhao, Hua
Enabling High Efficiency Direct Injection Engine with Naphtha Fuel through Partially Premixed Charge Compression Ignition Combustion2012-01-067704/16/2012
More stringent emissions standards along with higher fuel economy demands have obliged auto makers to develop technical solutions that exploit synergistic features from gasoline and diesel engines. To minimize NOx and soot trade-off, diesel powertrain has been developed to adopt increasingly complex and expensive technology such as extremely high pressure fuel injection systems, low pressure EGR, and variable valve timing. These attempts are associated with promoting Partially Premixed Charge Compression Ignition (PPC-CI) combustion via increasing mixing time and ignition delay. Alternatively, PPC-CI combustion can be achieved easier by using fuels with higher resistance to auto-ignition than conventional diesel fuel. Previous work has demonstrated the possibility of reducing the cost of future diesel after-treatment systems by using gasoline-like fuels. In this study, we start with a 0.5-liter single-cylinder direct injection spark ignition (DISI) engine and demonstrate that fuel
Chang, Junseok, Kalghatgi, Gautam, Amer, Amer, Viollet, Yoann
Experimental Investigation in Combustion Characteristics of Ethanol-gasoline Blends for Stratified Charge Engine2011-32-055111/08/2011
The increasing of global energy demand and stringent pollution regulations have promoted research on alternative fuels. In Thailand, ethanol, can be produced from many sources of national agriculture products as renewable fuel, which was strongly promoted by government due to its many merits for use in transportation field. In this study, combustion characteristics of ethanol-gasoline blend (20%, 85%, and 100%) as well as pure gasoline (E0) were investigated by using a swirl-generated constant volume combustion chamber. Flame propagations of different fuel blends were observed by high speed Schlieren photography technique while pressure history data were recorded for detailed combustion analysis. Combustion behavior, combustion duration and rate of pressure rise of all tested fuels were investigated in various swirl intensities and equivalence ratios. In addition, effect of swirl intensities and ethanol concentration on lean misfire limit were also discussed. The results showed that
Charoenphonphanich, Chinda, Ornman, Piyaboot, Karin, Preechar, Kosaka, Hidenori, Chollacoop, Nuwong
Effect of Hydrogen in CNG on Small Engine Performance and Emissions2011-24-020209/11/2011
Three-wheelers have a long history in Europe and Asia as extremely durable and reliable passenger and delivery vehicles. There are a number of reasons that have resulted into the proliferation of the 3-wheelers in developing countries especially in South Asian countries. 3-wheelers are quite economical in terms of manufacturing and maintenance. They have also earned huge popularity due to their easy maneuvering capabilities. The inherent engine design of 3-wheeler with conventional fuels have recognized for lower fuel economy and higher emissions. Concerns about energy security, air quality and need for sustainable economic growth are making it imperative that all nations, especially developing countries, begin making an accelerated transition from fossil fuels to clean energy alternatives. South Asian countries have already done a remarkable job of converting a large number of three-wheelers and buses to compressed natural gas (CNG), and in India there is an on-going effort to extend
SUBRAMANIAN, MUTHAN
The Twin Swirl “MR-Process” Combustion Mechanism and Conversion of Diesel Engines to Operate with Gaseous Fuels2011-24-006609/11/2011
Converting diesel engines to cheaper and cleaner fuels like LPG and CNG, with conventional methods needs a different combustion chamber, which has a lower compression ratio than a diesel engine (≻16:1) due to risk of detonation. This alteration makes the conversion process more expensive and difficult. On the other hand, decreasing a compression ratio leads to lower performance and efficiency compared to those of the original engine. To overcome this disadvantage it is proposed a novel mechanism for mixture formation and combustion, named as "MR-Process." This mechanism is realized in a combustion chamber MR-2 with twin-swirl turbulent flow. This chamber is suitable for operation with diesel fuels as well as with LPG and NG. In this paper are presented theoretical and experimental investigations of engines operating with "MR-Process" combustion mechanism.
Mehdiyev, Rafig, Ogun, Kurtulus, Ozcan, Enishan, Arslan, Hikmet, Babaoglu, Osman, TEKER, Hüseyin
A Comparison of Spray-Guided Stratified-Charge Combustion Performance with Outwardly-Opening Piezo and Multi-Hole Solenoid Injectors2011-01-121704/12/2011
This investigation was aimed at measuring the relative performance of two spray-guided, single-cylinder, spark-ignited direct-injected (SIDI) engine combustion system designs. The first utilizes an outwardly-opening poppet, piezo-actuated injector, and the second a conventional, solenoid operated, inwardly-opening multi-hole injector. The single-cylinder engine tests were limited to steady state, warmed-up conditions. The comparison showed that these two spray-guided combustion systems with two very different sprays had surprisingly close results and only differed in some details. Combustion stability and smoke emissions of the systems are comparable to each other over most of the load range. Over a simulated Federal Test Procedure (FTP) cycle, the multi-hole system had 15% lower hydrocarbon and 18% lower carbon monoxide emissions. Most significantly, the spray guided system with the multi-hole spray ended up having 3.0% lower fuel consumption than the piezo system over the simulated
Smith, James, Szekely Jr, Gerald, Solomon, Arun, Parrish, Scott
A Continuous Discharge Ignition System for EGR Limit Extension in SI Engines2011-01-066104/12/2011
A novel continuous inductive discharge ignition system has been developed that allows for variable duration ignition events in SI engines. The system uses a dual-coil design, where two coils are connected by a diode, combined with the multi-striking coil concept, to generate a continuous current flow through the spark plug. The current level and duration can be regulated by controlling the number of re-strikes that each coil performs or the energy density the primary coils are charged to. Compared to other extended duration systems, this system allows for fairly high current levels during the entire discharge event while avoiding the extremely high discharge levels associated with other, shorter duration, high energy ignition systems (e.g. the plasma jet [ 1 , 2 ], railplug [ 3 ] or laser ignition systems [ 4 , 5 , 6 , 7 , 8 ]. Tests on a single cylinder of a 4-cylinder engine indicated that the addition of the continuous discharge mode resulted in a larger improvement in burn rate and
Alger, Terrence, Gingrich, Jess, Mangold, Barrett, Roberts, Charles
A Review of Pre-Chamber Initiated Jet Ignition Combustion Systems2010-01-226310/25/2010
This paper reviews progress on turbulent jet ignition systems for otherwise standard spark ignition engines, with focus on small prechamber systems (≺3% of clearance volume) with auxiliary pre-chamber fueling. The review covers a range of systems including early designs such as those by Gussak and Oppenheim and more recent designs proposed by General Motors Corporation, FEV, Bosch and MAHLE Powertrain. A major advantage of jet ignition systems is that they enable very fast burn rates due to the ignition system producing multiple, distributed ignition sites, which consume the main charge rapidly and with minimal combustion variability. The locally distributed ignition sites allow for increased levels of dilution (lean burn/EGR) when compared to conventional spark ignition combustion. Dilution levels are comparable to those reported in recent homogeneous charge compression ignition (HCCI) systems. In addition, jet ignition systems have the potential for combustion phasing control and
Toulson, Elisa, Schock, Harold J., Attard, William P.
CFD Modeling of In-Cylinder Fuel-Air Mixing in a CNG-Fuelled SI Engine with Port Gas Injection2010-32-000309/28/2010
The concept of fuel-air mixture stratification is evaluated for a single cylinder, 200-cc CNG-fuelled SI engine with port gas injection (PGI). A detailed study based on three-dimensional computational fluid dynamics (CFD) modeling has been reported. Fuel-air stratification was observed in case of PGI compared to premixed fuel-air mixture formed by a conventional gas carburetor system. Overall stratification of more than 15% was observed for PGI between the rich and lean zones in the combustion chamber compared to less than 1% in case of premixed gas carburetor. It was observed that the gas injection location, direction, timing, duration and injection pressure have a significant effect on stratification pattern.
Garg, Manish, Ravikrishna, R
High Speed Endoscope Imaging to Supplement CFD Analysis and Combustion Testing for SIDI Engine Startup Development2010-01-034704/12/2010
Optimization of engine startup from crank to catalyst light-off is essential for achieving low emissions. For Spark Ignition Direct Injected (SIDI) engines, this requires optimization of the piston crown features, spray characteristics and control strategy. In this case study, high speed endoscope imaging was used to provide a qualitative confirmation of CFD spray predictions and to provide insight into engine starting in a “real” engine environment. The effect of piston feature was initially evaluated in a single cylinder engine running the dual-injection catalyst heating mode. The piston features were also assessed at part load and wide open throttle. The videos of the spray development were compared to CFD predictions. In the example case reported here, endoscope imaging showed that the baseline piston bowl was not effective in deflecting the spray toward the spark plug. Moving the piston bowl toward the injector gave a visible improvement in the spray deflection. Engine tests
Sczomak, David P., Zhao, Allan, Simon, Michael, Zeng, Yangbing
High Injection Pressures at the Upper Load Limit of Stratified Operation in a DISI Engine2009-01-265711/02/2009
This paper presents the results of investigations that were carried out on a single-cylinder spray-guided direct injection engine. The effects of injection pressures of up to 1000 bar on combustion and emissions at the stability limit of stratified load are presented. It is known that at low engine speeds, problems in mixture preparation occur due to insufficient in-cylinder motion at higher loads in stratified charge operation. Additionally, adverse effects appear at high engine speeds due to limited time for vaporization and mixture formation. Therefore, investigations at various engine speeds ranging from 2000 to 4000 rpm were performed. As a baseline, a production multihole injector is compared with an injector that has been specially adapted for higher injection pressures.
Buri, S., Busch, S., Kubach, H., Spicher, U.
Development of a Quasi-Dimensional Combustion Model for Stratified SI-Engines2009-01-265911/02/2009
The simulation of the combustion process is an essential part of the internal combustion engine development. For simulating whole engine maps quasi-dimensional models in combination with 1-D-flow simulations are widely used. This procedure is beneficial due to short computation times and accurate forecast capability of quasi-dimensional combustion models. For the simulation of homogeneous SI-engines the two-zone entrainment model is usually used, which is based on hemispherical flame propagation. In this work a new approach for the quasi-dimensional calculation of the stratified SI-engine combustion process is proposed, which is based on the two-zone entrainment model. This proven approach was extended with regard to the inhomogeneous air/fuel composition of stratified SI-engines that make a two-zone treatment not sufficient. Therefore, four unburnt zones are defined: a rich zone, a stoichiometrical zone, a lean zone and a remaining air zone. Furthermore in analogy to existing
Schmid, Andreas, Grill, Michael, Berner, Hans-Jürgen, Bargende, Michael, Rossa, Sascha, Böttcher, Michael
Structure of a Partially Premixed Iso-Octane/Air Turbulent V-Flame2009-01-265511/02/2009
The effect of the equivalence ratio gradient on a partially premixed, iso-octane/air, rod-stabilized turbulent V-flame was studied. Using a uniquely designed rectangular exit burner, the equivalence ratio was varied linearly along the exit of the burner while the global equivalence ratio was fixed at stoichiometric. A two-dimensional spectrometer provided line measurements along a wide spectral range (UV to near IR) and was used to identify radiating species to characterize each branch of the partially premixed flame (PPF). Chemiluminescence imaging of OH* and CH* was used to evaluate the general structure of the PPF and assess its potential use as an estimate of time averaged heat release rates. Planar Laser Induced Fluorescence of OH (OH-PLIF) images were collected to investigate the varying topography of the PPF. Variations of wrinkling scales, flame brush, and tribrachial flame structure were observed and discussed for different gradients in equivalence ratio.
Vena, P. C., Deschamps, B. M., Smallwood, G. J., Johnson, M. R.
Investigating Unburned Hydrocarbon (UHC) Emissions in a GDI Engine (Homogeneous and Stratified Modes) Using Formaldehyde LIF and Fast-FID Measurements in the Exhaust Port2007-01-402910/29/2007
An experimental method was set up in a single cylinder optical engine in GDI configuration to study UHC origins in both homogeneous and stratified operation. On the one hand, UHC were observed in the combustion chamber by formaldehyde LIF (excitation at 355 nm and collection from 400 to 470 nm). Formaldehyde is a natural UHC tracer since it results from partly decomposed fuel that has not been fully oxidized during combustion. A quartz cylinder liner was used in order to benefit from a large optical access. On the other hand, UHC emissions measurement were simultaneously performed with a fast FID analyzer whose sampling probe was located 2 cm downstream the exhaust valve, in one of the two exhaust ports. An instantaneous exhaust mass flow model was also developed using 0-D simulation. The computed mass flow rate was coupled to fast FID measurements to estimate instantaneous and cycle to cycle UHC emissions. Temporal form of the fast FID signals was correlated to the UHC visualizations
de Francqueville, L., Thirouard, B., Cherel, J.
The Prospects of Using Alcohol-Based Fuels in Stratified-Charge Spark-Ignition Engines2007-01-403410/29/2007
Near-term energy policy for ground transportation is likely to have a strong focus on both gains in efficiency as well as the use of alternate fuels; as both can reduce crude oil dependence and carbon loading on the environment. Stratified-charge spark-ignition direct-injection (SIDI) engines are capable of achieving significant gains in efficiency. In addition, these engines are likely to be run on alternative fuels. Specifically, lower alcohols such as ethanol and iso-butanol, which can be produced from renewable sources. SIDI engines, particularly the spray-guided variant, tend to be very sensitive to mixture preparation since fuel injection and ignition occur within a short time of each other. This close spacing is necessary to form a flammable mixture near the spark plug while maintaining an overall lean state in the combustion chamber. As a result, the physical properties of the fuel have a large effect on this process. Since alcohols tend to have higher heats of vaporization
Smith, James D., Sick, Volker
Modern Engine Technology from A to ZR-37309/28/2007
Part dictionary, part encyclopedia, Modern Engine Technology from A to Z will serve as your comprehensive reference guide for many years to come. Keywords throughout the text are in alphabetical order and highlighted in blue to make them easier to find, followed, where relevant, by subentries extending to as many as four sublevels. Full-color illustrations provide additional visual explanation to the reader. This book features: approximately 4,500 keywords, with detailed cross-references more than 1,700 illustrations, some in full color in-depth contributions from nearly 100 experts from industry and science engine development, both theory and practice
Van Basshuysen, Richard, Schaefer, Fred
Modern Engine Technology from A to ZR-373-TEST-REC09/28/2007
Part dictionary, part encyclopedia, Modern Engine Technology from A to Z will serve as your comprehensive reference guide for many years to come. Keywords throughout the text are in alphabetical order and highlighted in blue to make them easier to find, followed, where relevant, by subentries extending to as many as four sublevels. Full-color illustrations provide additional visual explanation to the reader. This book features: approximately 4,500 keywords, with detailed cross-references more than 1,700 illustrations, some in full color in-depth contributions from nearly 100 experts from industry and science engine development, both theory and practice
Van Basshuysen, Richard, Schaefer, Fred
Analysis for suitability of Loop and Cross Scavenged System for Stratified Charged Engine2007-24-006409/16/2007
The results obtained with Loop & Cross scavenged systems reveal that during early charging period the scavenged through losses are more in loop scavenged system in comparison to cross scavenged and in later part both shows considerable improvement still the probability of trapping of charge in cross scavenged are higher. Therefore stratification of charge helps in reducing the loss of fuel in both the system. But in case of cross scavenged system due to better trapping characteristics throughout the scavenging process leads to improved combustion too. Cross scavenged system employed with dual intake system shows reduction in fuel of the order of 26% & 29.7% for 40% & 50% flow through AASL, whereas, loop scavenged system shows 12.85% & 14.4% for the same flow through AASL.
Berwal, A. K., Gupta, V. K., Saxena, Mukesh
Experimental and Theoretical Investigation of Non-Quasi-Homogeneity of Flame Propagation in Stratified Media2007-01-013004/16/2007
A combined experimental and theoretical study is presented of the conditions under which flame propagation in stratified media can differ from “quasi-homogeneity”, i.e. propagation with the flame speed corresponding to the local equivalence ratio in the unburnt mixture. To this extent, OH chemiluminescence intensity measurements were performed in flames propagating through step-changes in equivalence ratio (from Φ=1 to 0.9, 0.6 and 0.5). The results showed a heat “back-support” into the flames, a phenomenon that was stronger with increasing equivalence ratio steps. In order to theoretically model flame propagation in fuel concentration gradients, heat flux from burnt gases and fuel mass fraction gradient across the reaction sheet were incorporated into the conventional asymptotic solution for flame propagation in perfectly premixed mixtures. Theoretical results provided an explanation for the experimental finding that departure from quasi-homogeneity is more pronounced in leaner
Kang, Taekyu, Kyritsis, Dimitrios C.
Experiments on Compression Ignition by Air Injection (CIBAI) in a Modified Single-Cylinder, Four-Stroke, Spark Ignition, Cooperative Fuel Research (CFR) Engine: A Novel Approach2006-01-335710/16/2006
Compression ignition by air injection (CIBAI) has been successfully achieved in a modified single cylinder, four-stroke, spark ignition cooperative fuel research (CFR) engine. This new combustion concept has the potential to replace traditional spark ignition and high-pressure fuel injection controlled ignition. Its high ignition energy provides the capability to rapidly ignite ultra-lean air-fuel mixtures, to maximize combustion compression with associated thermal efficiency, while reducing NOX formation. This paper presents the results of the first group of experiments conducted at West Virginia University on compression ignition by air injection (CIBAI). The objective of these experiments was to demonstrate experimentally the viability of achieving ignition by air injection (CIBAI) for controlled auto-ignition (CAI) in a CFR engine.
Echavarria, Fernando, Loth, John, Morris, Gary
Direct-Injected Hydrogen-Methane Mixtures in a Heavy-Duty Compression Ignition Engine2006-01-065304/03/2006
A diesel pilot-ignited, high-pressure direct-injection of natural gas heavy-duty single-cylinder engine was fuelled with both natural gas and blends of 10% and 23% by volume hydrogen in methane. A single operating condition (6 bar GIMEP, 0.5 ϕ, 800 RPM, 40%EGR) was selected, and the combustion phasing was varied from advanced (mid-point of combustion at top-dead-center) to late (mid-point of combustion at 15°ATDC). Replacing the natural gas with hydrogen/methane blend fuels was found to have a significant influence on engine emissions and on combustion stability. The use of 10%hydrogen was found to slightly reduce PM, CO, and tHC emissions, while improving combustion stability. 23%hydrogen was found to substantially reduce CO and tHC emissions, while slightly increasing NOx. The greatest reductions in CO and tHC, along with a significant reduction in PM, were observed at the latest combustion timings, where combustion stability was lowest. The high hydrogen-content fuel was found to
McTaggart-Cowan, G.P., Jones, H.L., Rogak, S.N., Bushe, W.K., Hill, P.G., Munshi, S.R.
A Study of Combustion Structure and Implications on Post-Oxidation Under Homogeneous and Stratified Operation in a DISI Engine2006-01-126204/03/2006
An experimental investigation into the structure and flame propagation characteristics of stratified and homogeneous combustion has been performed in an optically-accessible, direct-injection spark ignition (DISI) engine using OH planar laser-induced fluorescence (PLIF) imaging. Homogeneous and stratified operation was achieved by employing either early or late injection timing strategies during the intake or compression stroke respectively. Planar LIF OH images obtained revealed that for stratified operation, the 3D structure of the combustion zone is highly inhomogeneous and is predominantly due to high fuel concentration gradients which are formed as a result of local fuel mixture stratification. The images reveal a combustion structure which suggests that the flame propagation pathway is ultimately determined by the presence of these local fuel mixture inhomogeneities. In particular, the flame front and the burned gases appear to enclose the fresh/unburned gases which are locally
Kashdan, Julian T., Cherel, Jérome, Thirouard, Benoist
Model for Control of Combustion in a Piston Engine2006-01-040104/03/2006
Significant improvement of engine performance can be achieved by ushering in a micro-electronic system to control the execution of combustion - an exothermic process whose sole purpose is to generate pressure. Hence, the primary feedback for the controller is provided by a pressure transducer. The activators are piezo-electrically activated pintle valves of MEMS type. The task of the micro-electronic processor is to provide an accurate feed-forward signal for the actuators on the basis of the information obtained from the feedback signal, within a time interval between consecutive cycles. Furnished here for this purpose is an algorithm for an interface module between the pressure sensor and the governor. Concomitantly, the gains thus attainable in the reduction of fuel consumption and curtailment of pollutant formation are thereby assessed. The implementation of this method of approach is illustrated by application to a HCCI engine.
Bitar, Eilyan Y., Oppenheim, Antoni K., Schock, Harold J.
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