To elucidate the complex characteristics of pre-chamber combustion engines, the interaction of the hot gas jets initiated by an active narrow throated pre-chamber with lean premixed CH4/air in a heavy-duty engine was studied computationally. A twelve-hole KAUST proprietary pre-chamber geometry was investigated using CONVERGE software. The KAUST pre-chamber has an upper conical part with the spark plug, and fuel injector, followed by a straight narrow region called the throat and nozzles connecting the chambers. The simulations were run for an entire cycle, starting at the previous cycle's exhaust valve opening (EVO). The SAGE combustion model was used with the chemistry modeled using a reduced methane oxidation mechanism based on GRI Mech 3.0, which was validated against in-house OH chemiluminescence data from the optical engine experiments. Two different piston geometries, a flat piston geometry, and a more realistic bowl piston geometry were studied to understand the influence of jet

Sanal, Sangeeth, Echeverri Marquez, Manuel, Silva, Mickael, Cenker, Emre, Im, Hong G.

A Multi-Zone Combustion Model integrated with a fast Tabulated-Chemistry Approach applied for the Simulation of HCCI Engines supplied with Hydrogen or Carbon-Based Fuels

2022-01-045903/29/2022

To meet the stringent regulation imposed by EU and other legislators, various advanced combustion modes for Internal Combustion Engines (ICEs) are currently under investigation. Among those, Homogeneous Charge Compression Ignition (HCCI) appears a promising solution, simultaneously reducing pollutant emission and enhancing thermal efficiency. In this context, the numerical simulation has evolved into a powerful tool to investigate the combustion modes and to develop optimum control strategies, thanks to its greater flexibility and lower cost, if compared with the experiments. To simulate HCCI and other advanced combustion modes, based on charge stratifications in the combustion chamber, a general multi-zone model has been developed and implemented through user coding into a commercial software (GT-Power™). This model is based on a control mass Lagrangian multi-zone approach and it incorporates a procedure based on an off-line tabulation of chemical kinetics (Tabulated Kinetic of

De Bellis, Vincenzo, Malfi, Enrica, Fasulo, Giovanni, Lanotte, Alfredo, Bozza, Fabio

Understanding the impact of heat of vaporization on ɸ-sensitivity of toluene & ethanol reference fuels

2022-01-061803/29/2022

The low-temperature combustion (LTC) concept as a basis for high-efficiency, low-emission combustion technologies is getting more attentions among researchers and automotive industries. The modern engines which are working based on the (LTC) concept have specific fuel requirements. Fuel ɸ-sensitivity is a key factor to be considered for tailoring fuels for these engines. Fuel with high ɸ-sensitivity are more responsive to fuel or thermal stratifications, since the auto-ignition properties of different air-fuel mixtures of these fuels, with different equivalence ratio (ɸ) are more diverse. This diversity provide a smoother heat release rate in stratified condition. In this study a modified Cooperative Fuel Research (CFR) engine for homogeneous-charge compression ignition (HCCI) combustion is used to investigate the pressure sensitivity of 12 different toluene–ethanol reference fuels (TERFs) in three research octane number (RON) groups of 63, 84, and105. In this study, the effect of

Alemahdi, Nika, Garcia, Antonio, Boufaim, Emma, Aferiatd, Giulia, Tuner, Martin

Deceleration Cylinder Cutoff Emission Control Strategy for Ammonia Reduction in Spark Ignition Engines

2022-01-064903/29/2022

The newly-proposed Euro 7 emission standard has added regulation of ammonia emission for gasoline vehicles. This paper proposes a new emissions-control strategy to satisfy the regulated ammonia emissions levels. The control strategy utilizes deceleration cylinder cut-off (DCCO) to reduce/eliminate deceleration fuel cutoff (DFCO), reducing exhaust rich-lean air fuel ratio (A/F) variations and allowing tight management of exhaust three-way catalyst oxygen, which reduces CO/NOx ratio and NH3 formation rate inside catalytic converter. This results in more than 80% of ammonia emission reduction on the WLTP drive cycle without negative impact on all other regulated emissions.

luo, Xi, Yang, Xiaojian, Wilcutts, Mark, Ortiz-Soto, Elliott

Simulation Research on Ultra-lean Constant-volume Combustion Initiated by Spark-ignited Micro-fuel-jet

2022-01-051903/29/2022

In the ultra-lean combustion mode, the combustion temperature is relatively low, which is expected to avoid the high-temperature NOx generation. And it also can use excess air to fully oxidize CO, HC and Soot, to achieve cleaner combustion. But at the same time, ultra-lean combustion also has difficulties in ignition and flame propagation. This paper used CONVERGE to simulate the combustion process and products of a new ultra-lean combustion mode, which ignited the ultra-lean premixed fuel/air mixture with the spark-ignited micro-fuel-jet, in a constant-volume vessel with a 6-hole GDI injector. The differences of combustion processes and products were simulated for two spark-ignition positions including ‘on’ the micro-jet spray and ‘between’ two micro-jet sprays. It was found that the combustion duration (the time for burned-fuel-ratio from 10% to 90%) if igniting ‘on’ the micro-jet spray could be shortened by about 14.3%, and the amount of NOx generated would increase about 21.0%. At

Long, Quan, Li, Minglong, Zhou, Yang, Hu, Zongjie, Li, Liguang

Using multiple ignition sites and pressure sensing devices to determine the effect of air-fuel equivalence ratio on the morphology of knocking combustion

2022-01-052403/29/2022

Knocking combustion inherently presents an interaction between main flame front and end gas autoignition. Conventionally, it generates a high amplitude pressure wave traveling across the chamber, can be responsible for reducing the performance of the engine and can cause heavy damage to engine components. In order to study the phenomenon in a controllable way, experiments were performed on a specialized single-cylinder research engine fitted with a liner equipped with four equi-spaced spark plugs in the side so as to propagate various flames from those locations, and hence achieve more controlled knock events. In addition, six pressure transducers were employed at distinct locations to precisely record details of the autoignition event by monitoring pressure oscillations, and with them combustion characteristics and knock intensity. Four of the six transducers were mounted on the circumference of the liner (each next to one of the spark plugs), one was placed at the center of the

Uddeen, Kalim, Shi, Hao, Tang, Qinglong, Turner, James

Effects of Thermodynamic Conditions and Nozzle Geometry on the Methane Direct Injection Process in Internal Combustion Engines

2022-01-060603/29/2022

It's known direct injection of gaseous methane can involve the presence of under-expanded jets. Understanding the physics of such process is imperative for developing Direct Injection (DI) internal combustion engines fueled indeed by gaseous fuels. The paper presents an experimental-numerical characterization of the spray issued from an innovative multi-hole injector designed for application in heavy-duty engines. The experimental characterization of the jet evolution was recorded by means of schlieren imaging technique and then, using such measurements for the validation, a numerical simulation procedure was assessed. A high-order and density-based solver, capable of reproducing the most relevant features of the under-expanded jets, was developed within OpenFOAM framework. Both early and late injection configurations were investigated. They lead, during the engine cycle, to completely different upstream-to-downstream pressure ratios and so two representative Net Pressure Ratios (NPR

Duronio, Francesco, Montanaro, Alessandro, Allocca, Luigi, Ranieri, Stefano, De Vita, Angelo

Visualization of Passive Pre-chamber Jet Ignition in a Modified Gasoline Engine

2022-01-052903/29/2022

Pre-chamber turbulent jet ignition (TJI), an advanced ignition technology, has been considered for gasoline engines as a replacement for the traditional spark ignition. TJI has the potential to enable lean or EGR operations of engines and reduce cyclic variation. The hot turbulent jet is generated by burning a fuel/air mixture in a separate small volume called the pre-chamber. The higher pressure resulting from pre-chamber combustion pushes the combustion products into the main chamber in the form of a hot turbulent jet, which then ignites the lean mixture in the main chamber. Compared to a conventional spark plug, the hot jet has a much larger surface area leading to multiple ignition sites on its surface which can enhance the probability of successful ignition and cause faster heat release and flame propagation. The objectives of this paper are to examine the pre-chamber jet ignition process with a high-speed visualization and to understand the pre-chamber performance for a range of

Lee, Dong Eun, Yu, Tianxiao, Qiao, Li

Analysis of Cylinder to Cylinder Variations in a Turbocharged Spark Ignition Engine at lean burn operations

2022-32-004401/09/2022

In recent years, the improvement in the fuel efficiency and reduction in CO2 emission from internal combustion engines has been an urgent issue. The lean burn technology is one of the key technologies to improve thermal efficiency of SI engines. However, combustion stability deteriorates at lean burn operations. The reduction in cycle-to-cycle and cylinder-to-cylinder variations is one of the major issues to adapt the lean burn technique for production engines. However, the details of the causes and mechanisms for the combustion variations under the lean burn operations have not been cleared yet. The purpose of this study is to control cylinder to cylinder combustion variation. A conventional turbocharged direct injection SI engine was used as the test engine to investigate the effect of engine control parameters on the cylinder to cylinder variations. The engine speed is set at 2200 rpm and the intake pressure is set at 58, 78, 98 kPa respectively. In-cylinder pressure, intake

Yamaizumi, Ryo, Shi, Haoyun, Kuboyama, Tatsuya, Moriyoshi, Yasuo

E-Fuel applications in Non Road Mobile Machinery

2022-32-007401/09/2022

Professional users in particular will continue to rely on internal combustion engine drives in the future due to high power requirements and high daily energy consumption. Especially if they have to work in rural areas without the possibility of recharging batteries, such as in forestry or maintenance of road verges or railway lines. For these applications, it must be possible to run sustainable fuels for defossilization and drastically reduced CO2 emissions. This paper provides insights into a possible future fuel market and describes its evolution towards a more sustainable future from the perspective of a handheld equipment manufacturer. As developments in the fuel market are currently difficult to predict, manufacturers of hand-held power tools with combustion engines need to be prepared for changes in the composition of fuels that might become available on the market. This paper presents the engine performance results of both a 2-stroke engine and a 4-stroke engine, each with

von Gaertringen, Christoph Hiller, Schwerin, René, Schweiger, Stefan, Kölmel, Armin, Lochmann, Holger, Schmidt, Stephan, Zinner, Christian, Kirchberger, Roland, Gschanes, Dominik

Describing the Auto-Ignition Quality in Small, Air Cooled, Two Stroke Engines

2022-32-006301/09/2022

Auto-ignition quality is one of the most important properties in gasoline. Auto-ignition quality is today described by the Motor Octane Number (MON) and the Research Octane Number (RON). For modern, light duty, gasoline engines it has been quite well established that RON is the most accurate number. However, no study has been performed on hand held forest and garden products, such as chainsaws. Is the auto-ignition quality best described in the same way for these engines as for light duty engines? In this paper, a matrix of six different fuels with different combinations of MON and RON values were tested on a Husqvarna 550 XP Mark II, a modern air cooled, sequential stratified scavenging 2-stroke chainsaw engine. Ignition timing sweeps were performed and knock limited spark advance (KLSA) were calculated. Then the data has been analyzed with a multi-variate analysis of KLSA against both MON and RON to try to determine how MON and RON should be combined to best describe the anti-knock

Risberg, Per, Elm, Thomas, Bergman, Mikael, Hellquist, Fredrik, Karvo, Anna, Tripathi, Rupali

Combustion Performance of Methane Fermentation Gas with Hydrogen Addition under Various Ignition Timings

2022-32-004301/09/2022

Hydrogen (H2) addition is widely used for natural gas combustion to improve the engine efficiency. However, less attention was paid on the various ignition timings for the maximum brake torque (MBT) and brake thermal efficiency (BTE). In order to check the ignition timing effect, experiments were performed in a spark ignition engine with engine speed fixed on 1500 revolutions per minute (rpm). Firstly, CH4 was only used for combustion with excess air ratio (λ) changing from 0.8 to 1.4. Then, co-combustion of 50 vol% CH4 and 50 vol% CO2 was checked to simulate methane fermentation gas. Finally, H2 was added with volume percentage varying from 5% to 20%. Among these discussions, torque, brake mean effective pressure (BMEP), BTE and cylinder pressure were evaluated. Based on the results, high efficiency can be achieved by advancing the ignition timing with H2 addition at λ=1.4. However, with H2 addition, the ignition timing should be retarded to obtain higher BTE. At the lean-burn

Luo, Hongliang, Jin, Yu, An, Yanzhao, Matsumura, Yukihiko, Ichikawa, Takayuki, Kim, Wookyung, Nakashimada, Yutaka, Nishida, Keiya

Feasibility study of boosted DI technology for sport motorcycle

2022-32-007901/09/2022

The sport motorcycles continue to provide riders with the riding pleasure by the excellent potential of mobility performance brought by lightweight, compactness and high-performance powertrains. However, we are in a situation where we need to make efforts to reduce CO2 emission as much as possible on a global scale, and we also need to make serious efforts to reduce CO2 emission for sport motorcycles. The challenge for sport motorcycles from this perspective is a drastic improvement in fuel efficiency while maintaining the "vehicle dynamic performance", "drivability performance" and "to meet the latest exhaust emission regulation", and Yamaha has been proceeding the several feasibility studies aiming for realizing this challenge as advanced development. In one of the feasibility studies, "Downsizing Concept with boosted DI technology," we developed a research motorcycle equipped with a powertrain that achieved a specific output of 156kW / L (133kW / 0.85L) on a sport motorcycle. As a

Sato, Hayatoshi, Torigoshi, Masaki, Takase, Hiroki, Makita, Naoki

Effect of Different Fuel Supply System on Combustion Characteristics in Hydrogen SI Engine

2022-32-009201/09/2022

In recent years, internal combustion engine using hydrogen gas, has attracted attention as one solution to the problem of global warming. Hydrogen gas has excellent combustion characteristics such as wide limits of inflammability and fast burning velocity because of high diffusion rate. Therefore, it has been made to obtain stable ignition and combustion by adding hydrogen with lean mixture in spark ignition engines using hydrocarbon fuels and to be attempted efficient operation by engine researchers. The purpose of this study is to reduce cooling loss in a gas engine using hydrogen gas and hydrogen Mixer system (Mixer) engine was remodeled to hydrogen Port Injection (PI) system engine. In this report, the heterogeneity of hydrogen mixture is clarified by comparing the combustion characteristics of the Mixer and the PI, and the effect of the difference in hydrogen supply systems on cooling loss is system. Ignition delay of the PI system is shorter than that of the Mixer. This is to

Koshikawa, Shoi, Matsuya, Yuki, Sekine, Tsukasa, Matsumura, Eriko, Senda, Jiro, Morita, Gin, Nakazono, Toru

Improvements of Combustion and Emissions in a Natural Gas Fueled Engine with Hydrogen Enrichment and Optimized Injection Timings of the Diesel Fuel

2022-32-009501/09/2022

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

Evaluation of Pre-chamber Orifice Orientation in an Ethanol-Fueled Spark-Ignition Engine for Passenger Car Applications

03-15-04-002410/25/2021

The combination of an alternative alcohol-based fuel and a pre-chamber (PC) combustion process in a spark-ignition (SI) engine allows for both an extension of the lean limit and an increase of the indicated efficiency, while simultaneously achieving low engine-out emissions. The orientation of the PC orifices is crucial for the flow field inside the PC. Orifices with different swirl angles have already been investigated. However, the influence of the orifice offset from the PC center with a fixed swirl angle has not been part of previous research. This study presents investigations of ethanol-fueled combustion systems on a thermodynamic SI single-cylinder engine (SCE) for passenger car applications with a compression ratio (CR) of 16.4. Three active PC layouts with different orifice offsets were investigated. Their combustion behaviors were compared to that of a conventional SI combustion concept. In particular, variations of the relative air/fuel ratio (λ) were performed at both part

Burkardt, Patrick, Wouters, Christian, Pischinger, Stefan

Experimental Analysis of Heavy Duty CNG Engine based on its Aspiration and Fuel System

2021-26-011709/22/2021

Engine calibration involves the interaction of Electronic components with various engine systems like intake system, exhaust system, ignition system, etc. Emissions are the byproducts of combustion of fuel and air inside the combustion chamber. After-treatment systems generally take up the responsibility to scrape out harmful emissions from the engines. However, a good engine calibration will focus on emission reduction at source i.e. during the combustion itself. Thus, the intake of air and fuel in proper amount at each engine operating point is crucial for optimized engine performance and minimal emissions. The Intake system is an integral part of any internal combustion engine and it plays an important role to improve its performance and emission. Generally, for an SI engine, maintaining the stoichiometric A/F ratio is a challenging endeavor from an operational standpoint. Engine power, BSFC, torque and harmful emissions are much influenced by geometric aspect of intake manifold and

bandyopadhyay, Debjyoti, Sutar, Prasanna S, Sonawane, Shailesh Balkrishna, Rairikar, S D, Kavathekar, Kishorkumar, Thipse, Sukrut S, Kshirsagar, Chinmay, Kale, Samir

A Real-Time Chemical Equilibrium Mechanism for Control-Oriented Combustion Models

2021-26-032709/22/2021

To enable closed loop combustion control, in-cylinder pressure needs to be sensed and analyzed in real time on engine control units (ECU). Therefore, computationally light weight models are necessary. One way to reduce computational effort is to adapt the way how the composition of dissociating flue gas is calculated. The widely used chemical equilibrium mechanism developed by Olikara and Borman describes the gas phase products of burnt hydrocarbon fuels and is used as a reference throughout this work. The reaction scheme considers eleven species and seven elementary reactions. Different approaches to reduce computational effort while maintaining enough accuracy have been explored. As first approach, complete combustion approach is used. Secondly, mass fractions at various in-cylinder conditions are calculated using the reference mechanism and stored in tabulated form. Subsequently, linear interpolation is used to estimate mass fractions at any input condition. Thirdly, the mechanism

Patel, Akash, Eichmeier PhD, Johannes, Schwarte, Joachim, Mane, Archana

Numerical Investigation to Fuel Injection Strategy and Thermal Condition Impacts on GCI Combustion at Low and Medium Loads Using CFD

2021-01-115509/21/2021

This research numerically investigated the combustion process and exhaust emissions from a light-duty Gasoline Compression Ignition (GCI) engine operating at low load as well as medium load conditions using a commercial computational fluid dynamic (CFD) software Converge. The fuel injection strategies and thermal boundary conditions effects were examined to produce locally stratified and globally lean partially premixed compression ignition (PPCI) combustion. The effects of fuel injection pressure, number of injections, and the quantity of fuel injected in each pulse were examined and optimized for emissions and fuel consumption (FC) under the design constraints of 180 bar peak cylinder pressure (PCP) and 10 bar/° CA maximum pressure rise rate (MPRR). At 1250 rpm/3 bar indicated mean effective pressure (IMEP), the desired cylinder temperature and residual gas fraction at intake valve closing (IVC) was achieved by using exhaust gas rebreathing, uncooled exhaust gas recirculation (EGR

Kim, Jinsu, Sun, Harold, Zhang, Yu, Li, Hailin

Investigations into the Effects of Spark Plug Location on Knock Initiation by using Multiple Pressure Transducers

2021-01-115909/21/2021

Despite a long history of development, modern spark-ignition engines are still restricted in obtaining higher thermal efficiency and better performance by knock. Knocking combustion is an unnatural combustion phenomenon caused by the autoignition of unburned air-fuel mixture ahead of the propagating flame front. This work describes investigations into the significance of spark plug location (with respect to inlet and exhaust valve position) on the knock formation mechanism. To facilitate the investigation, four spark plugs were installed in a specialized liner at four equispaced distinct locations to propagate flames from those locations, which provoked a distinct flame travel from each and thus individual autoignition profiles. Six pressure transducers were arranged to precisely record the pressure oscillations, knock intensities, and combustion characteristics. Four of the six transducers were mounted on the circumference of the liner (each next to one of the spark plugs), one was

Uddeen, Kalim, Shi, Hao, Tang, Qinglong, Turner, James

Experimental Investigation of Cyclic Variation of Heat Release Dynamics of HCCI Combustion Engine

2021-01-117009/21/2021

Homogenous charge compression ignition (HCCI) combustion emerged as a potential technique for reducing automotive pollution. Controlling the combustion timing at different engine operating conditions is one of the major challenges for the commercial application of HCCI combustion engines. To control HCCI ignition timing, it is often necessary to know the characteristics of HCCI cyclic variations. In this study, cyclic combustion variations in an HCCI engine are analyzed. Combustion stability and cycle-to-cycle variations of HCCI combustion parameters were investigated on a modified four-stroke diesel engine. The experiments were conducted by varying intake air temperatures and relative air-fuel ratios at constant engine speed. In the steady-state engine operating condition, in-cylinder pressure signals of 2000 consecutive engine combustion cycles are acquired for each test condition. From this large volume of experimental data collected, cyclic variations of various combustion

Singh, Ajay, Maurya, Rakesh Kumar

Three-way catalyst model development using physical and machine learning methods for engine control design purposes

2021-01-122109/21/2021

Gasoline engine control strategies ensure a combustion control around stoichiometry. That is because the three-way catalytic converter allows CO and HC oxidation under lean operating conditions while ensuring NOx reduction for rich mixtures. In case of engine malfunction, the controller must adapt to compensate for potential torque losse and other critical attributes, potentially leading to significant deviation of the fuel-air mixture richness from stoichiometry and larger emission levels. Therefore, during development of the engine fault diagnostics the impact on the pollutant emissions must be considered. In this paper, a model-based development process is proposed. It is based on system simulation modelling techniques, where a complete exhaust line is represented in order to predict tail-pipe emissions under stoichiometric, lean and rich conditions, for engine control design purposes. Two different modelling approaches are applied and evaluated in this paper. First, a physics-based

LOUSSAIEF, Sana, Akhmetov, Yerlan, GROISIL, Melanie, Takahashi, Daisuke, Kuhara, Masaki, Isobe, Yoshiki, Mas, Peter

Engine Operation Strategies for the Alternative Diesel Fuel Oxymethylene Ether (OME): Evaluation based on Injection Rate Analyzer and 0D-/1D-Simulation

2021-01-119009/21/2021

Polyoxymethylene dimethyl ethers (OME) are promising alternative diesel fuels with a biogenic or electricity-based production, which offer carbon neutral mobility with internal combustion engines. Among other e-fuels, they stand out because of soot-free combustion, which resolves the trade-off between nitrogen oxide (NOx) and soot emissions. Additionally, long-chain OME have a high ignitability, indicated by a cetane number (CN) greater than 70. This opens up degrees of freedom in the injection strategy and enables simplifications compared to the operation with fossil diesel. This study investigates the hydraulic behavior of two solenoid injectors with different injector geometry for heavy-duty applications on an Injection Rate Analyzer (IRA) in diesel and OME operation. For OME, both injectors show longer injection delays in all injection pressure ranges investigated, increasing with rail pressure. However, these delays are less than two degrees of crank angle in the speed range of

Gelner, Alexander D., Höß, Rudolf, Zepf, Andreas, Härtl, Martin, Wachtmeister, Georg

Euro VII and Beyond with Hydrogen Combustion for Commercial Vehicle Applications: From Concept to Series Development

2021-01-119609/21/2021

One challenge for the development of commercial vehicles is the reduction of CO2 greenhouse, where hydrogen can help to reduce the fleet CO2. For instance, in Europe a drop in fleet consumption of 15% and 30% is set as target by the regulation until 2025 and 2030. Another challenge is EURO VII in EU or even already approved CARB HD Low NOx Regulation in USA, not only for Diesel but also for hydrogen combustion engines. In this study, first the requirements for the combustion and after-treatment system of a hydrogen engine are defined based on future emission regulations. The major advantages regarded to hydrogen combustion are due to the wide range of flammability and very high flame speed numbers compared to other fossil based fuels. Thus, it can be well used for lean burn combustion with much better fuel efficiency and very low NOx emissions with an ultra lean combustion. A comprehensive experimental investigation is performed on a HD 2 L single-cylinder engine. The hydrogen

Rezaei, Reza, Kovacs, David, Hayduk, Christopher, Mennig, Marian, Delebinski, Thaddaeus

Experimental and numerical investigation of a lean SI engine to be operated as range extender for hybrid powertrains

2021-24-000509/05/2021

In the last few years, concern about the environmental impact of vehicles has increased, considering the growth of the dangerous effects on health of noxious exhaust emissions. For this reason, car manufacturers are moving towards more efficient combustion systems for Spark Ignition (SI) engines, aiming to comply with the increasingly stringent regulation imposed by EU and other legislators. Engine operation with very lean air/fuel ratios has demonstrated to be a viable solution to this problem. Stable ultra-lean combustion can be obtained with a Pre-Chamber (PC) ignition system, installed in place of the conventional spark plug. The efficiency of this configuration in terms of performance and emissions is due to its combustion process, that starts in the PC and propagates in the main chamber in the form of multiple hot turbulent jets. In this work, the benefits of the PC were assessed in a production small SI engine, fueled with gasoline and equipped with a proper designed pre-chamber

Frasci, Emmanuele, Sementa, Paolo, Arsie, Ivan, Jannelli, Elio, Vaglieco, Bianca Maria

Experimental and Numerical Analyses of Direct and Port Water Injection in a Turbocharged Spark-Ignition Engine

2021-24-003509/05/2021

Water injection represents a promising tool to improve performance of spark-ignition engines. It allows reducing in-cylinder temperature, preventing knock risks. Optimizing the spark advance, water injection allows obtaining an increase of both efficiency and power output, particularly at medium and high loads. Water can be injected into the intake port or directly into the combustion chamber. In this paper, the authors investigated the effects of both direct and port water injection in a downsized PFI spark-ignition engine at high load operation. Different water-to-fuel ratios have been analyzed for both configurations. For the experimental analysis, low-pressure water injectors have been installed in the intake ports of the engine under study, upstream of the fuel injectors. Experimental tests have been carried out at various operating points. Furthermore, engine operation with port water injection has been simulated by means of the AVL Fire 3-D code. The numerical analysis has been

Lanni, Davide, Galloni, Enzo, Fontana, Gustavo, Erme, Giovanni

Sub-23 nm Particle Measurement and Assessment of Their Volatile Fraction at Exhaust of a Four Cylinder GDI Engine Fueled with E10 and E85 Under Transient Conditions

2021-24-008709/05/2021

In view of the new emission regulations seeking to lower the particle cut-off size down to the current 23 nm, an extensive comprehension on the nature of sub-23 nm particles is crucial. In this regard, a new challenge lies ahead considering an even more massive use of biofuels. The objective of this research study was to characterize the sub-23 nm particles and to evaluate their volatile organic fraction (VOF) from a high performance, 1.8 L gasoline direct injection (GDI) engine under the Worldwide harmonized Light vehicles Test Cycle (WLTC). Particle emissions were measured through an Engine Exhaust Particle Sizer (EEPS) capable of particle sizing and counting in the range 5.6 - 560 nm. The sampling and conditioning were performed by both a single diluter and the Dekati Engine Exhaust Diluter (DEED) a Particle Measurement Programme (PMP) compliant sample conditioning system. The temperature of the dilution air at the first dilution stage and of the evaporation chamber in the DEED were

Catapano, Francesco, Di Iorio, Silvana, Magno, Agnese, Vaglieco, Bianca Maria

Analysis of Knock Transient Response to Controlled Coolant Flow Rate Variations in a S.I. Engine

2021-24-005309/05/2021

The effects of a controlled coolant flow rate variation on knock tendency are investigated on a small S.I. engine. The analysis concerns the transient behavior of the unburned gas temperature to a controlled variation in the coolant flow rate. This phenomenological investigation aims at preventing knock through a proper thermal management as an efficient alternative to the currently adopted strategies. Moreover, the proposed approach is particularly useful for hybrid-electric powertrain, where the engine is expected to operate in the highest efficiency region by adopting high compression ratios and full stoichiometric map. The analysis was carried out through an experimental campaign, where the control of cylinder wall temperature was achieved by means of an electrically driven water pump. The spark advance and the air/fuel ratio were properly varied in order to operate with advanced spark timing and stoichiometric mixture at full load. Both stationary and transient engine operations

Falbo, Luigi, Perrone, Diego, Castiglione, Teresa, Algieri, Angelo, Bova, Sergio

Aircraft Flame Arrestor Installation Guidelines and Test Methods

ARP5776 (Current)

08/26/2021

The scope of this document is to provide pertinent information on demonstrating the performance of Flame Arrestors, also known as Fuel Vent Protectors (FVPs), in preventing the propagation of a deflagration when the arrestors are subjected to aerospace-representative flames produced by the venting of flammable gas through the arrestor. Test procedures for two separate combustion-loading profiles are presented herein: The flame hold test condition, and the flame propagation test condition. For the flame hold test condition, the applicability of two separate critical flows is discussed in which one flow results in the greatest flame arrestor temperature and a second flow results in the greatest temperature of the surrounding structure. These guidelines are necessary for OEMs and fuel/vent system designers to validate the flame arresting-performance of the subassemblies comprising of the flame arrestors and relevant surrounding structures in an installation environment representative of

AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee

Aircraft Flame Arrestor Installation Guidelines and Test Methods

ARP5776-TEST-REC (Historical)08/26/2021

AE-5A Aerospace Fuel, Inerting and Lubrication Sys Committee

Power and Torque Determination for UAS Engines Having Maximum Power Ratings at or Below 22.4 kW

ARP6971 (Current)

04/07/2021

This recommended practice is applicable to reciprocating engines powering unmanned aerial vehicles (UAV) having rated power values less than 22.4 kW, and which are not to be used for human transport.

E-39 Unmanned Aircraft Propulsion Committee

Power and Torque Determination for UAS Engines Having Maximum Power Ratings at or Below 22.4 kW

ARP6971-TEST-REC (Historical)04/07/2021

E-39 Unmanned Aircraft Propulsion Committee

Experimental and 0D Numerical Investigation of Ultra-Lean Combustion Concept to Improve the Efficiency of SI Engine

2021-01-038404/06/2021

Recently, the car manufacturers are moving towards innovative Spark Ignition (SI) engine architectures with unconventional combustion concepts, aiming to comply with the stringent regulation imposed by EU and other legislators. The introduction of burdensome cycles for vehicle homologation, indeed, requires an engine characterized by a high efficiency in the most of its operating conditions, for which a conventional SI engine results to be ineffective. Combustion systems which work with very lean air/fuel mixture have demonstrated to be a promising solution to this concern. Higher specific heat ratio, minor heat losses and increased knock resistance indeed allow improving fuel consumption. Additionally, the lower combustion temperatures enable to reduce NOX production. Since conventional SI engines can work with a limited amount of excess air, alternative solutions are being developed to overcome this constraint and reach the above benefit. Among all these solutions, replacing the

De Bellis, Vincenzo, Malfi, Enrica, Bozza, Fabio, KUMAR, Deepak, Serrano, David, Dulbecco, Alessio, Zaccardi, Jean-Marc

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