Browse Topic: Air / fuel ratio

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11/26/2025

This document is one of a set covering the whole spectrum of aircraft interaction with lightning. This document is intended to describe how to conduct lightning direct effects tests and indirect system upset effects tests. Indirect effects upset and damage tolerance tests for individual equipment items are addressed in DO-160/ED-14. Documents relating to other aspects of the certification process, including definition of the lightning environment, zoning, and indirect effects certification are listed in Section 2. This document presents test techniques for simulated lightning testing of aircraft and the associated systems. This document does not include design criteria nor does it specify which items should or should not be tested. Acceptable levels of damage and/or pass/fail criteria for the qualification tests must be approved by the cognizant certification authority for each particular case. When lightning tests are a part of a certification plan, the test methods described herein are an acceptable means, but not the only means, of meeting the test requirements of the certification plan. Each test method is set out in a uniform format, describing the test purpose, test object, test setup, test waveforms (voltage and/or current), measurements and data recording, test procedure and data interpretation. Guidance is provided on how to select the appropriate test or series of tests, and how the test results can be assessed. Natural lightning is a complex and variable phenomenon and its interaction with different types of vehicles may be manifested in many different ways. It is not intended that every test described herein be applied to every system requiring lightning verification tests. The document is written so that specific aspects of the environment can be called out for each specific program as dictated by the vehicle design, performance and mission constraints.

AE-2 Lightning Committee

Tight

AIR12122024A (Current)12/12/2024

New Scoop

A-6 Aerospace Actuation, Control and Fluid Power Systems

test download manager cache issue 12/27/2023 at 9 am

SAE-PP-0908512/27/2023

test download manager cache issue 12/27/2023 at 9 am

Mutagaana, Festo

Regression 11/1/23

SAE-PP-0892211/1/2023

Lorem Ipsum

Mutagaana, Festo

A Numerical Study on the Effect of a Pre-Chamber Initiated Turbulent Jet on Main Chamber Combustion

2022-01-0469

3/29/2022

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 on main chamber combustion. Varying the piston geometries results in different free jet times and hence main chamber combustion characteristics. Pre-chamber fuel ratio (PCFR) 6% of the total amount of fuel was investigated while keeping the global excess air ratios (λ) condition a constant value of 2.0. Both piston cases resulted in similar pre-chamber pressurization, with almost the same pre-chamber discharge and the equal pressure difference between pre-and main-chamber (ΔP) at the start of jet ejection. Different combustion behaviors were observed on analysis of the heat release rate in the main chamber. The importance of turbulence generated by the pre-chamber-initiated jets was further studied. It was observed that free jet time is a critical factor in developing turbulence in the main chamber. This increase in turbulence helps in increasing the burning velocity causing faster combustion. The influence of the jet-piston interaction is also analyzed as that determines the combustion behavior in the later CAD.

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

Aircraft Flame Arrestor Installation Guidelines and Test Methods

ARP5776 (Current)

8/26/2021

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 the actual unique aircraft installation. Flame arrestors are components of the fuel system plumbing and, as such, are subject to the same requirements of other fuel system plumbing components. This document presupposes that the flame arrestor is properly installed; note that existing documentation (refer to ARP8615) provides detailed guidance for testing a flame arrestor as a component of a system, including standard requirements for testing the installation of a flame arrestor. Flame arrestors are installed on other aircraft system installations besides fuel vent systems. These include: fuel tank inerting system (within the distribution system at the tank entrance), electrical pump inlets and external aircraft drain masts. Although only the fuel tank vent system installation is specifically addressed in this document, portions of the detailed flame test procedures may be useful to qualify flame arrestors in other applications, e.g., the flame propagation test which is applicable to flame arrestors installed in the inerting system.

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)

4/7/2021

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

7.0.104 - Managing Distributed Systems Development through Model-Based E/E-Architecture Design

SAE-PP-002802/4/2021

This paper sketches a model based E/E-architecture analysis and design process for the development of distributed in-vehicle systems. Together with a model based system development, the sketched analysis and design process results in a cost-effective E/E-architecture which fulfills all the requirements for the developed in-vehicle system. As an example scenario, the integration of a new feature into a car, which requires integrating a new distributed function into the existing E/E-architecture of the car, is shown.

Lname, Fname

Model-Based Precise Air-Fuel Ratio Control for Gaseous Fueled Engines

02-13-03-0017

10/9/2020

In this article, an adaptive state estimation algorithm for precise air-fuel ratio (AFR) control is presented. AFR control is a critical part of internal combustion engine (ICE) control, and tight AFR control delivers lower engine emissions, better engine fuel economy, and better engine transient performance. The proposed control algorithm significantly improves transient AFR control to eliminate and reduce the amplitude of the lean and rich spikes during transients. The new algorithm is first demonstrated in simulation (using Matlab/SimulinkTM and GT-PowerTM) and then verified on a test engine. The engine tests are conducted using the European Transient Cycle (ETC) with HoribaTM double-ended dynamometer. The developed algorithm utilizes a nonlinear physics-based engine model in the observer and advanced control principles with modifications to solve real industrial control issues. This method dramatically reduces on-engine AFR transient calibration efforts, which was one of the objectives of this research. The developed algorithm is applicable for various fuel mixer configurations including pre-turbocharger, pre-throttle, and post-throttle. It also demonstrates robustness to engine to engine inconsistency. The novel algorithm is developed by following model-led design process. WoodwardTM natural gas engines and engine control modules are used for algorithm development and validation.

Han, Yi, Young, Peter

Candidate Improvements to Dedicated Short Range Communications (DSRC) Message Set Dictionary [SAE J2735] Using Systems Engineering Methods

J3067_202010 (Current)

10/6/2020

This document is not a standard, it is a candidate for a standard being submitted to SAE for their consideration as a comment to SAE J2735. The term SAE J2735 SE candidate is used within this document to refer to this submission. This document specifies dialogs, messages, and the data frames and data elements that make up the messages specifically for use by applications intended to utilize the 5.9 GHz Dedicated Short Range Communications for Wireless Access in Vehicular Environments (DSRC/WAVE, referenced in this document simply as “DSRC"), communications systems. Although the scope of this Standard is focused on DSRC, these dialogs, messages, data frames and data elements have been designed, to the extent possible, to be of use for applications that may be deployed in conjunction with other wireless communications technologies. This standard therefore specifies the definitive message structure and provides sufficient background information to allow readers to properly interpret the message definitions from the point of view of an application developer implementing the messages according to the DSRC Standards.

V2X Communications Steering Committee

V2X Communications Message Set Dictionary

J2735_202007 (Historical)

7/23/2020

This SAE standard specifies a message set, and its data frames and data elements, for use by applications that use vehicle-to-everything (V2X) communications systems. While the data dictionary was originally designed for use over DSRC, this document is intended to be independent of the underlying communications protocols used to exchange data between participants in V2X applications.

V2X Core Technical Committee

Preignition Rating of Spark Plugs

J549_202006 (Current)

6/15/2020

This SAE Recommended Practice describes the equipment and procedures used in obtaining preignition ratings of spark plugs.

Ignition Standards Committee

Impact of Spark Plasma Length on Flame Kernel Development under Flow Condition

2020-01-11144/14/2020

Advanced ignition systems with enhanced discharge current have been extensively investigated in research, since they are highly regarded as having the potential to overcome challenges that arise when spark-ignition engines are running under lean or EGR diluted conditions. Local flow field is also of particular importance to improve the ignitability of the air-fuel mixture in SI engines as the spark plasma channel can be stretched by the flow across the spark gap, leading to longer plasma length, thus more thermal spark energy distributed to the air-fuel mixture in the vicinity of the spark plug. Research results have shown that a constantly high discharge current is effective to maintain a stable spark plasma channel with less restrikes and longer plasma holding period. However, with the further increase in discharge current, plasma channel becomes thicker, and the stretched plasma length becomes shorter under a constant flow speed, which may suppress the advantages of the enhanced discharge current. In this work, the interaction between discharge current level and plasma length under flow conditions is investigated. Whether a thick but shorter plasma channel or a thin but stretched farther plasma channel is more effective for the flame kernel formation is discussed to provide an insight into the influence of the plasma length on flame initiation. An optical combustion chamber platform along with a cross-flow generation system was used to study the plasma channel behavior; an in-house developed spark energy management module was employed to boost the discharge current level up to 3 A; in order to decouple the effect of discharge duration on flame initiation, the total discharge process was controlled within 0.8 ms.

Zhu, Hua, Tan, Qingyuan, Yu, Xiao, Yang, Zhenyi, Liang, Li, Zheng, Ming, Reader, Graham, Qian, Jin

The Prospect and Benefits of Using the Partial-Averaged Navier-Stokes Method for Engine Flows

2020-01-11074/14/2020

This paper presents calculations of engine flows by using the Partially-Averaged Navier Stokes (PANS) method (Girimaji [1]; [2]). The PANS is a scale-resolving turbulence computational approach designed to resolve large scale fluctuations and model the remainder with appropriate closures. Depending upon the prescribed cut-off length (filter width) the method adjusts seamlessly from the Reynolds-Averaged Navier-Stokes (RANS) to the Direct Numerical Solution (DNS) of the Navier-Stokes equations. The PANS method was successfully used for many applications but mainly on static geometries, e.g. Basara et al. [3]; [4]. This is due to the calculation of the cut-off control parameter which requires that the resolved kinetic energy is known and this is usually obtained by suitably averaging of the resolved field. Such averaging process is expensive and impractical for engines as it would require averaging per cycles. A recently published work on PANS (Basara et al. [5]) opens a prospect of more cost-effective engine calculations. This new PANS approach solves the additional equation for a total resolved turbulent kinetic energy which enables continuous (in situ) update of the resolution parameter fk. Thus fk. is dynamically specified in time and space depending on the flow and computational meshes. Calculation results of the IC engine will be compared with the measurements which include cycle-to-cycle variations and emission data.

Basara, Branislav, Pavlovic, Zoran, Girimaji, Sharath

Numerical Modeling of Spray Formation under Flash-boiling Conditions

2020-01-03284/14/2020

Flash boiling occurs in sprays when the ambient gas pressure is lower than the saturation pressure of the injected fuel. In the present work, a numerical study was conducted to investigate solid-cone spray behaviors under various flash-boiling conditions. A new spray cone angle correlation that is a function of injection parameters was developed and used for spray initialization at the nozzle exit to capture plume interactions and the global spray shape. The spray-breakup regime control was adjusted to enable catastrophic droplet breakup, characterized by Rayleigh-Taylor (RT) breakup, near the nozzle exit. The model was validated against experimental spray data from five different injectors, including both multi-hole and single-hole injectors, with injection pressure varying from 100 to 200 bar. Different fuels, including iso-octane, n-heptane, n-pentane, ethanol, and n-butanol, were investigated under a wide range of flash-boiling conditions, in which flash boiling was induced by high injected fuel temperature, ranging from 323 to 493 K, and/or low ambient gas pressure, ranging from 0.1 bar to atmospheric. It is found that flash boiling can significantly increase the spray cone angle near the nozzle exit, causing spray spreading and obvious plume interactions, which strongly influence the global spray shape. For flash boiling induced by high fuel temperature, penetration length tends to decrease because of enhanced liquid breakup and vaporization. For flash boiling induced by low ambient gas pressure, the reduced resistance from the ambient gas and enhanced droplet breakup lead to competing effects on spray penetration. By using the modified breakup regime control and spray cone angle correlation, the model shows good agreement with experimental data in capturing spray spreading, plume interactions and global spray shape in all simulated cases. The modeling approach proposed in this paper is expected to be universally applicable to all solid-cone flash-boiling sprays.

Tao, Mingyuan, Liang, Long, Wang, Yue, Meeks, Ellen

An Experimental Study on the Effect of Exhaust Gas Recirculation on a Natural Gas-Diesel Dual-Fuel Engine

2020-01-03104/14/2020

Natural gas (NG)-diesel dual-fuel combustion can be a suitable solution to reduce the overall CO2 emissions of heavy-duty vehicles using diesel engines. One configuration of such a dual-fuel engine can be port injection of NG to form a combustible air-NG mixture in the cylinder. This mixture is then ignited by a direct injection of diesel. Other potential advantages of such an engine include the flexibility of switching back to diesel-only mode, reduced hardware development costs and lower soot emissions. However, the trade-off is lower brake thermal efficiency (BTE) and higher hydrocarbon emissions, especially methane, at low load and/or high engine speed conditions. Advancing the diesel injection timing tends to improve the BTE but may cause the NOx emissions to increase. In this study, exhaust gas recirculation (EGR) is used in combination with the diesel injection timing control to demonstrate the compromises between lowering NOx, soot, and methane emissions while maintaining diesel-like BTE. Determining such optimal operating conditions can not only reduce the consumption of diesel and NG but may also enhance the life of the exhaust after-treatment system components such as the diesel particulate filter (DPF). Tests are performed on a heavy-duty, four-stroke, NG-diesel dual-fuel single-cylinder research engine with independent and flexible air and fuel delivery systems. Two load levels corresponding to 50% and 75% of full load are investigated at a constant engine speed of 1000 rpm and NG-diesel energy ratio of 3:1. Results show that advancing the diesel injection timing at a low EGR ratio (~10% based on intake and exhaust CO2) can reduce the soot and methane emissions but cause the NOx emissions to increase. Further increase of EGR to up to 18% can reduce the NOx emissions while limiting the soot emissions to the heavy-duty regulatory limits. In general, with the use of EGR, dual-fuel combustion can provide an improved NOx-soot trade-off compared to diesel-only combustion.

Dev, Shouvik, Guo, Hongsheng, Lafrance, Simon, Liko, Brian

Virtual Development of Injector Spray Targeting by Coupling 3D-CFD Simulations with Optical Investigations

2020-01-11574/14/2020

Further improvements of internal combustion engines to reduce fuel consumption and to face future legislation constraints are strictly related to the study of mixture formation. The reason for that is the desire to supply the engine with homogeneous charge, towards the direction of a global stoichiometric blend in the combustion chamber. Fuel evaporation and thus mixture quality mostly depend on injector atomization features and charge motion within the cylinder. 3D-CFD simulations offer great potential to study not only injector atomization quality but also the evaporation behavior. Nevertheless coupling optical measurements and simulations for injector analysis is an open discussion because of the large number of influencing parameters and interactions affecting the fuel injection’s reproducibility. For this purpose, detailed numerical investigations are used to describe the injection phenomena. These intensive calculations are not advisable considering CFD virtual engine development. It is rather reasonable to find a methodology for a numerical characterization of the fuel injection process that takes into account both macroscopic and microscopic spray properties and to integrate these models into the complete engine simulations. Based on these concepts a fast response 3D-CFD tool has been developed at IVK/FKFS Stuttgart with the purpose of reliable and time effective simulation using dedicated models for internal combustion engines. The purpose of this paper is a further development of the model and the spray simulation within the 3D-CFD-tool QuickSim, coupling optical measurements performed in a constant volume chamber and a new methodology to calibrate the simulations with a repeatable analysis of both experimental and numerical results. Axial and radial penetration curves, injection tip velocity, as well as jet angles were measured and evaluated. In addition to the investigation a PDA-system is used for detecting droplet velocities and diameters. These data were used to calibrate the injection model, enhancing the simulations’ reliability. Finally the modelled injectors were tested in a single-cylinder engine through 3D-CFD simulations, with the aim of studying the differences in the mixture formation and improving engine efficiency.

Vacca, Antonino, Hummel, Simon, Müller, Karsten, Reichenbacher, Marc, Chiodi, Marco, Bargende, Michael

Effects on Cycle-to-Cycle Variations and Knocking Combustion of Turbulent Jet Ignition (TJI) with a Small Volume Pre-Chamber

2020-01-11194/14/2020

Turbulent jet ignition (TJI) has the advantages of improving burning rates and expanding lean burn limitations of gasoline engines. Based on a single cylinder engine, combustion process with different ignition methods, including single spark ignition, twin spark ignition, one-hole TJI and seven-hole TJI, are studied in this work. Experiments are carried out under conditions with different air/fuel equivalence ratios and different engine loads. Results show that the cycle-to-cycle variations of TJI combustion, which is evaluated by coefficient of variations (CoV) of IMEP and CoV of peak pressure, are obviously reduced due to the fast burning rate induced by the jet flame, and one-hole TJI combustion has the best combustion stability, especially for reducing the CoV of peak pressure. Furthermore, under full-load conditions, pressure oscillations are observed in TJI combustion, and the intensity distribution is different from that in SI combustion, which means that the roots causing the pressure oscillations of TJI and SI are different. Pressure oscillations in TJI combustion are caused by the local fast burning rate of the hot jets, while the pressure oscillations of SI are caused by end-gas auto-ignition, which randomly happens during combustion. Under TJI knock condition, excellent combustion stability and great auto-ignition consistency can still be achieved. Considering these features of TJI combustion, a new combustion concept, jet induced compression ignition (JICI), and a different ignition method, spark combined jet ignition (SCJI), are proposed in order to organize combustion with high efficiency, stability and controllability.

Hua, Jianxiong, Zhou, Lei, Gao, Qiang, Feng, Zhonghui

Use of Butanol Blend Fuels on Diesel Engines - Effects on Combustion and Emissions

2020-01-0333

4/14/2020

Butanol, a four-carbon alcohol, is considered in the last years as an interesting alternative fuel, both for Diesel and for gasoline application. Its advantages for engine operation are: good miscibility with gasoline and diesel fuels, higher calorific value than ethanol, lower hygroscopicity, lower corrosivity and possibility of replacing aviation fuels. Like ethanol, butanol can be produced as a biomass-based renewable fuel or from fossil sources. In the research project, DiBut (Diesel and butanol) addition of butanol to Diesel fuel was investigated from the points of view of engine combustion and of influences on exhaust aftertreatment systems and emissions. One investigated engine (E1) was with emission class “EU Stage 3A” for construction machines, another one, engine (E2) was HD Euro VI. The most important findings are: with higher butanol content, there is a lower heat value of the fuel and there is lower torque at full load. With Bu30 the conversion rates of CO and HC in the oxidation catalyst (DOC) are slightly lower, light-off temperatures are a little higher and NO2 production is lower. The PM-emissions with Bu30 are lower, so the soot loading of DPF takes a longer time. No impacts of Bu30 on NOx reduction rates of the SCR-system and on the non-legislated gaseous emission components were found. The operation of engine (E1) with Bu30 (30% vol butanol in fuel) was instable at lower part load due to the lower Cetane Number of the blend fuel. The electronic control system of the engine (E2) compensated very well the varying properties of fuels up to Bu30. For both investigated engines, the butanol rate (Bu30) can be considered as a limit for a problem-free engine starting and operation.

Engelmann, Danilo, Czerwinski, Jan, Nauroy lng, Hervé, Comte, Pierre, Hüssy lng, Andreas

CO2 Neutral Heavy-Duty Engine Concept with RCCI Combustion Using Seaweed-based Fuels

2020-01-0808

4/14/2020

This paper focusses on the application of bioalcohols (ethanol and butanol) derived from seaweed in Heavy-Duty (HD) Compression Ignition (CI) combustion engines. Seaweed-based fuels do not claim land and are not in competition with the food chain. Currently, the application of high octane bioalcohols is limited to Spark Ignition (SI) engines. The Reactivity Controlled Compression Ignition (RCCI) combustion concept allows the use of these low carbon fuels in CI engines which have higher efficiencies associated with them than SI engines. This contributes to the reduction of tailpipe CO2 emissions as required by (future) legislation and reducing fuel consumption, i.e. Total-Cost-of-Ownership (TCO). Furthermore, it opens the HD transport market for these low carbon bioalcohol fuels from a novel sustainable biomass source. In this paper, both the production of seaweed-based fuels and the application of these fuels in CI engines is discussed. Ethanol and butanol are considered as the most viable fuels derived from seaweed. The potential of these fuels has been evaluated for the dual-fuel RCCI mode regarding efficiency and NOx emissions. The operating conditions that have been varied are mainly the fuel blend ratio (BR), fuel injection timing, and EGR rate on both a HD single-cylinder and on a HD multi-cylinder engine. The results for E85/diesel-RCCI demonstrate that CI engine-like efficiencies are feasible. The gross Indicated Thermal Efficiency (ITE) reaches up to 52% and 46.5% using E85 in a single-cylinder and a multi-cylinder engine, respectively. The first results using biomass based butanol show greater difficulty in realizing targeted efficiencies on the multi-cylinder engine due to the higher fuel reactivity and higher boiling temperature than ethanol. The gross ITE reaches up to 51.6% and 38.5% using butanol in a single-cylinder and a multi-cylinder engine, respectively. The demonstrated potential of seaweed-based fuels is an important driver for upscaling the production process of these fuels. Furthermore, future development activities will focus on improving the brake thermal efficiency of the RCCI engine running on seaweed-based fuels. Improving the low reactivity fuel-air mixture preparation will be key to achieve this.

Seykens, Xander, Bekdemir, Cemil, Han, Jinlin, Willems, Robbert, Van Hal, Jaap

Potential Analysis and Virtual Development of SI Engines Operated with Synthetic Fuel DMC+

2020-01-0342

4/14/2020

On the way to emission-free mobility, future fuels must be CO2 neutral. To achieve this, synthetic fuels are being developed. In order to better assess the effects of the new fuels on the engine process, simulation models are being developed that reproduce the chemical and physical properties of these fuels. In this paper, the fuel DMC+ is examined. DMC+ (a mixture of dimethyl carbonate (DMC) and methyl formate (MeFo) mainly, characterized by the lack of C-C Bonds and high oxygen content) offers advantages with regard to evaporation heat, demand of oxygen and knock resistance. Furthermore, its combustion is almost particle free. With the aid of modern 0D/1D simulation methods, an assessment of the potential of DMC+ can be made. It is shown that the simulative conversion of a state-of-the-art gasoline engine to DMC+ fuel offers advantages in terms of efficiency in many operating points even if the engine design is not altered. This is mainly due to the higher knock resistance and the lower temperatures in the intake stroke resulting from the higher amount of evaporated fuel. For a fixed amount of fuel energy, a lower air mass flow rate is needed, making the fuel particularly interesting for down-sizing concepts. Therefore, the engine design is adapted for the new fuel to take full advantage of the fluid properties. In a first step, the adaptions include the compression ratio, the engine displacement and the turbocharger matching. A considerable efficiency gain in the whole operating range can be demonstrated, making DMC+ a highly promising prospective for future SI engines.

Wagner, Cornelius, Grill, Michael, Keskin, Mahir-Tim, Bargende, Michael, Cai, Liming, Pitsch, Heinz

Influence of Nozzle Opening Pressure, Fuel Injection Timing and Compression Ratio on the Performance of Compression Ignition Engine Fueled with Biodiesel-Diesel-Butanol Blends

2020-01-0299

4/14/2020

Biodiesel from vegetable waste can be utilized as fuel for compression ignition engine. This experimental study used biodiesel extracted from the cauliflower outer leaves and butanol from vegetable waste as property enhancer to fuel the diesel engine. This study consists of two stages: Solubility and properties test of various proportions of diesel biodiesel butanol blends to obtain an optimal fuel blend that possesses closer properties to that of diesel; followed by testing the optimal blend in a modified engine for nozzle opening pressure (180, 190, 200 and 210 bar), fuel injection timing (23, 26, 29 and 320 before top dead centre) and compression ratio (16: 1, 17.5:1, 19:1 and 20.5:1). The optimal level of these parameters was attained using L16 orthogonal array and Taguchi method. Test results showed that the blend containing 40% biodiesel 20% diesel and 40% butanol can be used as fuel for diesel engine. The diesel engine was operated under 210 bar of nozzle opening pressure, 260before top dead center of fuel injection timing and 19:1 of compression ratio. This optimal blend produced closer brake thermal efficiency, in-cylinder peak pressure, peak heat release rate, ignition delay, and combustion duration which were found to be similar compared to that of diesel (above 40% of rated power). The emissions produced by this blend were found lower compared to that of diesel operated at higher brake power condition (above 50% of rated power). This study enables to utilize the waste vegetables and renewable resources to fuel diesel engine and replacing the diesel to a certain extent.

B, Prabakaran

Motor Vehicle Emission Control Quality Monitoring for On-Road Driving: Dynamic Signature Recognition of NO _x & NH ₃ Emissions

2020-01-03724/14/2020

Motor vehicle emission testing during on-road driving is important to assess a vehicle’s exhaust emission control design, its compliance with Federal regulations and its impact on air quality. The U.S. Environmental Protection Agency (EPA) has been developing new approaches to screen the characteristics of vehicle dynamic emission control behaviors (its operating signature) while driving both on-road and on-dynamometer. The so-called “signature device” used for this testing is equipped with an O2/NOx sensor, thermocouple and GPS to record dynamic exhaust NOx concentration, air fuel ratio-controlled tailpipe lambda (λ), tailpipe temperature and vehicle speed (acceleration). In the early EPA research, signature screening was used to characterize a vehicle’s PCM control behaviors (cause/effect bijectivity), which help distinguish operation in normal control state-space and abnormal state-space. Currently, signature devices are being used to recognize when ammonia (NH3) has been emitted and to estimate the presence of NOx and NH3 within on-road and on-dyno driving. The presence of NH3 is observed by the signature device’s NOx sensor at times when tailpipe lambda readings are biased rich, after the engine three-way-catalyst (TWC) has warmed up. To study the production of NH3, EPA established a vehicle test program to gather and evaluate the emissions from on-road driving conditions. The same driving conditions were then replicated on an indoor chassis dynamometer (dyno) while using a bag analyzer bench, a raw exhaust modal bench, and a signature device to measure vehicle emissions and control behaviors. EPA ascertained, under certain operating conditions, that stoichiometric engine exhaust passing through a TWC can create hydrogen (CO+H2O→H2), which is then available to produce unregulated ammonia (CO+NO+H2→NH3). These reactions can accelerate when the engine operates with slightly rich-biased lambda introduced either by control or by calibration design. Under current Light-Duty Tier 3 emission regulations, NOx and NMOG emissions are counted together, creating an “opportunity” for more of this type of engine operation.

Tang, Xiaoguo, Kargul, John, McBryde, Dan

Impact of the Injection Strategy on Soot Reactivity and Particle Properties of a GDI Engine

2020-01-03924/14/2020

The gradual global tightening of emission legislation for particulate matter emissions requires the development of new gasoline engine exhaust aftertreatment systems. For this reason, the development of gasoline direct injection engines aims at the reduction of particulate emissions by application of a Gasoline Particulate Filter (GPF). The regeneration temperature of GPF depend on soot reactivity towards oxidation and therefore on particle properties. In this study, the soot reactivity is correlated with nanostructural characteristics of primary gasoline particles as a function of specific engine injection parameters. The investigations on particle emissions were carried out on a turbocharged 4-cylinder GDI-engine that allows the variation of injection parameters. The emitted engine soot particles have been in-situ characterized towards their number and size distribution using an engine exhaust particle sizer (EEPS). Ex-situ analytics focuses on the analysis of oxidation kinetics and the nanostructural characteristics affecting soot reactivity significantly. The oxidation kinetics were determined by temperature programmed oxidation (TPO) employing thermogravimetric analysis (TGA). The temperature at the maximum of the reaction rate is referred to Tmax, where low temperatures are linked to high reactivity. In addition, the nanostructure analysis of primary particles (graphene layer length, tortuosity and separation distance) was also investigated by using high resolution transmission microscopy (HRTEM) and an image analysis algorithm. Findings from this work show that soot reactivity relies significantly on the quality of mixture formation of a GDI engine depending on injection strategy. These findings are in very good agreement with the nanostructural parameters obtained by high-resolution transmission electron microscopy. Soot particles formed in a relatively homogeneous air/fuel mixture due to optimized injection parameters show a high soot reactivity (Tmax ≈ 525°C) and an amorphous carbon nanostructure. Such primary particles are characterized by short mean graphene layer length (Lmean ≈ 0.5 nm) and an unordered configuration resulting in an increased separation distance (Dmean ≈ 1 nm). In addition, approximately a comparable number of small (Dp ≈ 5...25 nm) and large particles (Dp ≈ 30...100 nm) are generated. Conversely, inhomogeneous mixtures result in increased formation of primary particles showing long, extended and more ordered graphene (Lmean ≈ 0.55 nm, Dmean = 0.4 nm), which in turn lead to low soot reactivity (Tmax ≈ 615°C).

Koch, Sergej, Kubach, Heiko, Velji, Amin, Koch, Thomas, Hagen, Fabian P., Bockhorn, Henning, Loukou, Alexandra, Trimis, Dimosthenis, Suntz, Rainer

Impact of Multiple Injection Strategies on Performance and Emissions of Methanol PPC under Low Load Operation

2020-01-05564/14/2020

There is growing global interest in using renewable alcohols to reduce the greenhouse gases and the reliance on conventional fossil fuels. Recent studies show that methanol combined with partially premixed combustion provide clear performance and emission benefits compared to conventional diesel diffusion combustion. Nonetheless, high unburned hydrocarbon (HC) and carbon monoxide (CO) emissions can be stated as the main PPC drawback in light load condition when using high octane fuel such as Methanol with single injection strategy. Thus, the present experimental study has been carried out to investigate the influence of multiple injection strategies on the performance and emissions with methanol fuel in partially premixed combustion. Specifically, the main objective is to reduce HC, CO and simultaneously increase the gross indicated efficiency compared to single injection strategy. The work was performed with a single cylinder heavy duty engine, operated at 4 bar gross indicated mean effective pressure, and an engine speed of 1200 rpm. Double and triple injections were implemented with varying dwells, injection timings and fuel mass proportions. The experimental results were analyzed with a merit function to select the optimal injection strategy. Concerning emissions, the constraints for the merit function were based on the EURO VI limits, while the highest gross indicated efficiency for single injection was used to define the performance constraint. The results revealed that with proper dwell and mass proportion, multiple injection strategies can improve the gross indicated efficiency and reduce the emissions compare to single injection strategy.

Aziz, Amir, Garcia, Antonio, Pinto Dos Santos, Clarisse, Tuner, Martin

Control of Ignition Timing and Combustion Phase by Means of Injection Strategy for Jet-Controlled Compression Ignition Mode in a Light Duty Diesel Engine

2020-01-05554/14/2020

Controllability of ignition timing and combustion phase by means of dual-fuel direct injection strategy in jet-controlled compression ignition mode were investigated in a light-duty prototype diesel engine. Blended fuel with lower reactivity was delivered in the early period of compression stroke to form the premixed charge, while diesel fuel which has higher reactivity was injected near TDC to trigger the ignition. The effects of several important injection parameters including pre-injection timing, jet-injection timing, pre- injection pressure and ratio of pre-injection in the total heat value of injected fuel were discussed. Numerical Simulation by using CFD software was also conducted under similar operating conditions. The experimental results indicate that the jet-injection timing shows robust controllability on the start of combustion under all the engine load conditions. Pre-injection timing/pressure/ratio show little impact on the start of combustion due to low reaction activity of premixed charge. Early pre-injection timing and larger pre-injection pressure lead to wall-wetting and poor vaporization of pre-injected fuel especially at light duty conditions, as a result, combustion duration increases, and CO/THC emissions enhance. Larger pre-injection ratio in the total heat value of injected fuel prolongs combustion duration and enhances CO/THC emissions at lower engine load, reduces combustion duration and CO/THC emissions at higher engine load. The numerical simulation results demonstrate the two-stage combustion process described according to the experimental results. The two-stage combustion process of diesel jet JCCI mode is featured by the evolution of intermediate species such as H2O2 and OH, and the main emission products such as CO and NOx. At last, the effects of injection parameters on JCCI combustion characteristics are summarized.

Zhu, Jingyu, Bo, Li, Long, Wuqiang

Smart Spark Plug for Proper Combustion Timing in Gasoline Engines and Detection of Misfire and Knock

2020-01-07904/14/2020

Internal combustion engines are required to achieve production goals of better fuel economy, improved fuel economy and reduced emissions in order to meet the current and future stringent standards. To achieve these goals, it is essential to control the combustion process using an in-cylinder combustion sensor and a system that produces a feedback signal to the ECU. This paper presents a system based on combustion ionization that includes a newly developed smart spark plug capable of sensing the whole combustion process. A unique feature of the smart spark plug system is its ability to sense the early stages of combustion and produce a complete ion current signal that accurately identifies and can be used for the control of the start of combustion. This is not the case for the conventional spark plug where the start of combustion cannot be determined from the ion current signal because its early part is distorted or completely overshadowed by the strong electromagnetic field produced by the spark ignition system. In addition to its ability to detect and control the start of combustion, the new system can detect other combustion related problems such as misfire and knock. The paper describes the construction of the smart spark plug and compares its ion current signal with that produced by the conventional spark plug. The new system, developed and patented by IC LLC, can be applied in current production spark ignition engines as well as for the development of future advanced concepts engines.

Assaad, Kamal, Henein, Naeim A.

Effects of Geometry on Passive Pre-Chamber Combustion Characteristics

2020-01-08214/14/2020

Towards a fundamental understanding of the ignition characteristics of pre-chamber (PC) combustion engines, computational fluid dynamics (CFD) simulations were conducted using CONVERGE. To assist the initial design of the KAUST pre-chamber engine experiments, the primary focus of the present study was to assess the impact of design parameters such as throat diameter, nozzle diameter, and nozzle length. The well-stirred reactor combustion model coupled with a methane oxidation mechanism reduced from GRI 3.0 was used. A homogeneous charge of methane and air with λ = 1.3 on both the PC and main chamber (MC) was assumed. The geometrical parameters were shown to affect the pre-chamber combustion characteristics, such as pressure build-up, radical formation, and heat release as well as the composition of the jets penetrating and igniting the main chamber charge. In addition, the backflow of species pushed inside the pre-chamber due to the flow reversal (FR) event was analyzed. It was found that the narrow throat type of pre-chamber is strongly influenced by the throat diameter, but weakly influence by nozzle length. A flow reversal pattern was observed, which promoted the accumulation of intermediate species in the PC, leading to a secondary heat release.

Silva, Mickael, Sanal, Sangeeth, Hlaing, Ponnya, Cenker, Emre, Johansson, Bengt, Im, Hong G.

Improving Heavy Duty Natural Gas Engine Efficiency: A Systematic Approach to Application of Dedicated EGR

2020-01-08184/14/2020

The worldwide trend of tightening CO2 emissions standards and desire for near zero emissions is driving development of high efficiency natural gas engines for a low CO2 replacement of traditional diesel engines. A Cummins Westport ISX12 G was previously converted to a Dedicated EGR® (D-EGR®) configuration with two out of the six cylinders acting as the EGR producing cylinders. Using a systems approach, the combustion and turbocharging systems were optimized for improved efficiency while maintaining the potential for achieving 0.02 g/bhp-hr NOX standards. A prototype variable nozzle turbocharger was selected to maintain the stock torque curve. The EGR delivery method enabled a reduction in pre-turbine pressure as the turbine was not required to be undersized to drive EGR. A high energy Dual Coil Offset (DCO®) ignition system was utilized to maintain stable combustion with increased EGR rates. High compression ratio, reduced squish pistons were designed to maintain MBT combustion phasing and fast burn rates along the torque curve. The final engine configuration was tested on the Heavy-Duty Supplemental Emissions Test (SET), a 13-mode steady-state engine dynamometer test. The engine was able to achieve a weighted average efficiency improvement of 12% over the baseline configuration with a peak BTE of 41.7%.

Kocsis, Michael C., Mitchell, Robert, Moiz, Ahmed Abdul, Kalaskar, Vickey, Williams, D. Ryan, Sjovall, Scott

Combustion System Development in GAC Turbocharged Miller GDI Engine with 0.5L/Cylinder

2020-01-08384/14/2020

GAC Group has set up two modular engine families, G and GS, for various vehicle classes equipping demands. G family engines, which have already gone through three generations, target for the higher torque and power, the lower fuel consumption and the future strict emission standards. For the latest generation, new technologies were added to achieve the development goals based on the previous modular engines. For example, miller combustion cycle with increased compression ratio is introduced in the newer engine combustion system. Additional key technologies such as 350 bar injection system and high tumble intake ports are also applied. The combustion system development, which established on the GAC Combustion Controlling System (GCCS), was facilitated by integrated use of advanced optical measurements and computational fluid dynamics for improving the in-cylinder flow, fuel sprays and the interaction between them. This paper presents the analytical work done to develop the combustion systems. A higher tumble intake port design enhances the motion in intake process, the well-organized in-cylinder flow may bend over the sprays and keep them from interacting with the cylinder. The redesigned spray structure and piston bowl could do good for a reasonable mixture formation, which decreases the soot and HC emissions, especially for the cold-start conditions. Results from engine test bench experiments show that all of the new generation of the 0.5L/cylinder turbocharged DI gasoline engines can meet the strict legislation for nearest or some considerable time to come.

Li, Yuhuai, Chen, Hong, Du, Jiakun, Wu, Jian, Zhan, Wenfeng, Wu, Guangquan, Lin, Sicong, Shao, Fake

Different Methods to Improve the Exhaust Gas Temperature in Modern Stage V Off-Road Diesel Engine over Transient Emission Cycles

2020-01-09034/14/2020

This paper presents several methods to improve the exhaust gas temperature of a modern diesel engine. A high exhaust gas temperature is needed to improve the after-treatment system efficiency and particulate filter regeneration in low engine loads. This study is based on experimental measurements of two Stage 5 level off-road diesel engines. The effect of the different heating methods determined over steady state runs and emission and performance are presented with standard emission transient test procedure (NRTC). In the first step of the study, an intake air restriction and an exhaust gas restriction method are compared. The intake restriction produces better fuel economy over the measuring cycle. However, with the exhaust restriction, higher exhaust gas temperature can be achieved in low engine loads. In the second phase of study, the intake air restriction method was implemented in the research engine. In addition, active waste gate controlling, and injection retardation methods were taken in use for heating purposes. The engine performance was determined with normal calibration and with high exhaust temperature calibration. The differences to the exhaust temperature, engine performance and emission were presented in transient emission cycle NRTC.

Lauren, Mika, Karhu, Toomas, Niemi, Seppo, Laivola, Miika, Ekman, Jan, Spoof-Tuomi, Kirsi

Discharge Current Management for Diluted Combustion under Forced Flow Conditions

2020-01-11184/14/2020

Lean burn or EGR diluted combustion with enhanced charge motion is effective in improving the efficiency of spark ignition engines. However, the ignition process under these conditions is getting more challenging due to higher ignition energy required by the lean or diluted mixture, as well as the interactions of the gas flow on the flame kernel. Enhanced spark discharge energy is essential to initiate the combustion under these conditions. Moreover, the discharge process should be more carefully controlled to improve the effectiveness of the spark. In this study, spark ignition systems with boosted discharge energy are used to ignite diluted air-fuel mixture under forced flow conditions. The impacts of the discharge current level, the discharge duration and the discharge current profile on the ignition are investigated in detail using optical diagnosis. It is evident from the results that extended discharge duration helps promote the flame propagation, though the effectiveness is limited when the duration exceeds the required minimum value for a self-sustained flame kernel. A higher discharge current level is favorable for generating a stronger flame kernel. With similar discharge energy delivered to the spark gap, a high-current spark with a shorter duration performs better than a longer duration low-current spark. Then the impacts of discharge current profiles are studied. Three spark discharge strategies, including a low-current continuous discharge, a high-current multi-pulse discharge, and a very high transient current discharge, are used in the comparison. The results reveal that sufficiently long discharge duration is critical for success ignition under the tested flow condition. Among the three ignition strategies, the low-current continuous spark discharge performs the best, even with the lowest discharge energy, due mainly to the continuous nature of the spark discharge.

Yang, Zhenyi, Wang, Linyan, Sandhu, Navjot S., Yu, Xiao, Zheng, Ming

On Maximizing Argon Engines' Performance via Subzero Intake Temperatures in HCCI Mode at High Compression Ratios

2020-01-11334/14/2020

The improvement of the indicated thermal efficiency of an argon power cycle (replacing nitrogen with argon in the combustion reaction) is investigated in a CFR engine at high compression ratios in homogeneous charge compression ignition (HCCI) mode. The study combines the two effects that can increase the thermodynamic efficiency as predicted by the ideal Otto cycle: high specific heat ratio (provided by argon), and high compression ratios. However, since argon has relatively low heat capacity (at constant volume), it results in high in-cylinder temperatures, which in turn, leads to the occurrence of knock. Knock limits the feasible range of compression ratios and further increasing the compression ratio can cause serious damage to the engine due to the high pressure rise rate caused by advancing the combustion phasing. The technique proposed in this study in order to avoid intense knock of an argon cycle at high compression ratios is to cool the intake charge to subzero temperatures which leads to lower in-cylinder temperatures and hence, less possibility of having knock. The main variable in this study was the intake temperature which was investigated at 40.0 °C and -6.0 °C which corresponded to low and high compression ratios, respectively. Emission analysis shows that the low in-cylinder temperature of the cooled case led to less complete combustion, and so, lower combustion efficiency. Since nitrogen is replaced with argon, NOx was only formed in negligible amounts due to some nitrogen traces in the used gasses cylinders. Furthermore, the cooled charge required more work to be done in the gas exchange process due to the decrease in the intake pressure caused by cooling the intake which deteriorated the gas exchange efficiency. The heat losses factor was found to be the main parameter that dictated the improvement of the thermodynamic efficiency and it was found that the indicated thermal efficiency was deteriorated for the cooled case as a result of all the aforementioned factors. Although the values of the thermodynamic efficiency at high compression ratios did not meet the expectations based on the ideal Otto cycle due to the assumptions of the ideal cycle, the obtained values, in general, are relatively high.

Elkhazraji, Ali, Mohammed, Abdulrahman, Jan, Sufyan, Masurier, Jean-Baptiste, Dibble, Robert, Johansson, Bengt

Effects of Direct Injection Timing and Air Dilution on the Combustion and Emissions Characteristics of Stratified Flame Ignited (SFI) Hybrid Combustion in a 4-Stroke PFI/DI Gasoline Engine

2020-01-11394/14/2020

Controlled Auto-Ignition (CAI) combustion can effectively improve the thermal efficiency of conventional spark ignition (SI) gasoline engines, due to shortened combustion processes caused by multi-point auto-ignition. However, its commercial application is limited by the difficulties in controlling ignition timing and violent heat release process at high loads. Stratified flame ignited (SFI) hybrid combustion, a concept in which rich mixture around spark plug is consumed by flame propagation after spark ignition and the unburned lean mixture closing to cylinder wall auto-ignites in the increasing in-cylinder temperature during flame propagation, was proposed to overcome these challenges. The combustion and emissions characteristics in the SFI hybrid combustion were experimentally investigated in a single-cylinder 4-stroke gasoline engine operating at medium to high loads when direct injection timing was retarded from -100 °CA to -40 °CA after top dead center (ATDC) and excess air coefficient was increased from 1.0 to 1.2 at the direct injection ratio of 30%. The experimental results show that direct injection timing and excess air coefficient control the ignition timing and combustion duration. Ignition timing advances with increased excess air coefficient at the same direct injection timing. Long combustion duration occurs at earlier direct injection timing close to -100 °CA ATDC or very late direct injection timing near -40 °CA ATDC at different excess air coefficients. In the meantime, combustion duration reduces with increased excess air coefficient when auto-ignition occurs during the combustion processes, while it increases with excess air coefficient without auto-ignition. Nitrogen oxides emissions increase first and then decrease with retarded direct injection timing at different excess air coefficients, and their maximum values occur at the direct injection timing of -60°CA ATDC.

Fu, Xue-Qing, He, Bang-Quan, Li, Hongtao, Chen, Tao, Zhao, Hua, Yang, Jian-Jun, Liu, Shuang-Xi, Gao, Haiyang

Investigation of the Impacts of Spark Plug Orientation on Combustion Stability under Lean SI Operation

2020-01-11214/14/2020

The increasingly stringent restrictions on vehicle emissions and fuel consumption are driving the development of gasoline engines towards lean combustion. Increasing ignition energy has been considered an effective way to achieve lean operation conditions. To further improve the lean limit of engine combustion, the influence of the spark plug orientation on the combustion stability under lean operation should be explored. In this investigation, the original machine spark plug orientation, 90 degrees clockwise rotation, and 180 degrees clockwise rotation are studied to analyze the impact of spark plug orientation. The combustion experiment was carried out under the condition of low excess air ratio of the original machine and high excess air ratio with a 450 mA high energy ignition. It is found that changing the orientation of the spark plug had little effect on combustion at low excess air ratio; however, under high excess air ratio (ultra-lean operation), spark plug orientation had a great influence on combustion stability. The combustion stability can be significantly improved when the spark plug orientation is vertical to the intake direction. What’s more, we found that when the engine speed was low as 1000rpm, the effects of the spark plug orientation were not very clear. However, when the engine speed increased to 2000rpm, the lean operation limit can be improved from an excess air ratio of 1.78 to 1.96 by adjusting the orientation of the spark plug.

Gu, Qifan, Xu, Min, Ye, Chang, Hung, David, Li, Xuesong

Application of the Passive MAHLE Jet Ignition System and Synergies with Miller Cycle and Exhaust Gas Recirculation

2020-01-02834/14/2020

Driven by legislation, economics and increasing societal awareness, engine and vehicle manufacturers are facing increasing pressure to reduce vehicle emissions and deliver improved fuel economy. Significant reductions in carbon dioxide (CO2) emissions will need to be achieved to meet these requirements whilst at the same time satisfying the more stringent forthcoming emissions regulations. This focus on techniques to reduce the tailpipe CO2 is increasing the interest in novel combustion technologies, including dilute combustion in gasoline engines. The pre-chamber based jet ignition concept produces high energy jets of partially combusted species that induce ignition at multiple locations in the main combustion chamber to enable rapid, stable combustion, even with dilute mixtures. The present study focusses on the beneficial synergies of the pre-chamber system with high geometric compression ratio (CR), Miller cycle operation and cooled external exhaust gas recirculation (EGR). The study has been undertaken using the MAHLE 1.5 liter, 3-cylinder, downsized demonstrator engine. The interaction of the various technologies applied to the engine, will be discussed and the improvements in fuel consumption due to the technology package that has been applied relative to the baseline engine will be presented. A critical challenge for pre-chamber based combustion systems is achieving operation over a wide operating region and under low load and cold start conditions. Results from the study demonstrating the capability of the pre-chamber concept to enable whole map operation as well as idle stability, catalyst light-off capability to a conventional central spark plug will also be presented.

Cooper, Adrian, Harrington, Anthony, Bassett, Michael, Reader, Simon, Bunce, Michael

A Novel Design of Engine Misfire Detection System Suitable for Small Capacity S.I. Engine for Two Wheeled Vehicle

2020-01-02674/14/2020

As per the OBD II regulations, it is essential to detect and monitor the misfire event in an I.C. engine. Misfiring of an I.C. engine affects the quality of combustion and degrades the performance of catalyst convertor which can lead to an increase of emissions. Misfire event can be categorized as partial or complete, based on amount of combustion occurred during that particular engine cycle. Most of the production engine for non-two wheeler vehicle identifies misfire by monitoring angular acceleration of the engine crank-shaft. However, single cylinder engine with lower capacity (less than 300 cubic centimeter) provides challenges to identify misfire due to low mechanical inertia of the I.C. engine using the same approach. The problem of misfire identification for this category of I.C. engine turn out to be more challenging due to presence of various load disturbances on the powertrain. Ion current sensing is one of the alternate method to detect misfire, which received good attention during the last decade of the previous century. When the air-fuel mixture ignites inside the I.C. engine cylinder, air particles get ionize. By applying a suitable high-voltage on spark plug, it is possible to measure the ion current as the amount of ion current reflects the level of ionization of air fuel mixture. The ion current measurement system presented in this paper is implemented in a production vehicle ignition system for two wheeled vehicles. The vehicle ignition system is unique due to the shorted terminals of high & low voltage sides. Due to the shorted primary and secondary connection, it is challenging to implement ion current measurement system using available research work. The proposed novel design of ion current measurement system accommodates the above constraint. The ion current signal is captured during normal combustion event as well as by creating misfire in the combustion. There are significant changes observed in the ion current signal with and without misfire. The information extracted from the ion current signal is utilized to detect the misfire. The proposed design is analyzed with suitable 1D theoretical model of the ignition system.

Bagade, Monika Jayprakash, Das, Himadri Bhushan, Raveendranath Sr, Arjun, Jabez Dhinagar, S

Influence of Port Water Injection on the Combustion Characteristics and Exhaust Emissions in a Spark-Ignition Direct-Injection Engine

2020-01-02944/14/2020

It is well known that engine downsizing is still the main energy-saving technology for spark-ignition direct-injection (SIDI) engine. However, with the continuous increase of the boosting ratio, the gasoline engine is often accompanied by the occurrence of knocking, which has the drawback to run the engine at retarded combustion phasing. Besides, in order to protect the turbine blades from being sintered by high exhaust temperature, the strategies of fuel enrichment are often taken to reduce the combustion temperature, which ultimately leads to a high level of particulate number emission. Therefore, to address the issues discussed above, the port water injection (PWI) techniques on a 1.2-L turbocharged, three-cylinder, SIDI engine were investigated. Measurements indicate that the optimization of spark timing has a significant impact on its performance. The two factors of the water substance itself and spark advance caused by the knock mitigation are trade-offs, which eventually affect the combustion performance. Under knock limited spark advance (KLSA) condition, we find that the application of port water injection could effectively advance the combustion phasing and reduce exhaust gas temperature, which makes it possible to eliminate fuel enrichment and further enhances the fuel economy improvement at the maximum power point. As a result, about 5.2%-18.4% improvements in the fuel economy are obtained under different engine operating conditions. For the exhaust emissions, due to the increasing heat capacity of the mixture and the elimination of fuel enrichment, port water injection techniques cause an 85.3% reduction in particle number concentration. However, it shows that for a given λ, an increase in the water/fuel ratio would cause higher THC emissions, which is contributed to the occurrence of more quenching caused by higher peak combustion pressure. Finally, the potential of PWI on the engine combustion characteristics and emissions performance was revealed.

Fan, Yadong, Wu, Tianbao, Li, Xuesong, Xu, Min, Hung, David

Numerical Investigation of the Effects of Port Water Injection Timing on Performance and Emissions in a Gasoline Direct Injection Engine

2020-01-02874/14/2020

Port water injection is considered as a promising strategy to further improve the combustion performance of internal combustion engines for its benefit in knock resistance by reducing the cylinder temperature. A thorough investigation of the port water injection technique is required to fully understand its effects on the engine combustion process. This study explores the potential of the port water injection technique in improving the performance of a turbo charged Gasoline Direct Injection engine. A 3D computational fluid dynamics model is applied to simulate the in-cylinder mixing and combustion for this engine both with and without water injection. Different water injection timings are investigated and it is found that the injection timing greatly effects the mass of water which enters the combustion chamber, both in liquid and vapor form. Comparison have been given between the original engine and the water injection one and the results show that the water injection can reduce the cylinder temperature both in the compressing and combustion strokes. The pressure oscillation is also suppressed which indicates a better knocking resistance for water injection strategy. An optimized injection timings could be found for a particular load condition and also lead to a better combustion performance and emissions.

Yin, Peng, Li, Xuesong, Hung, David, Fan, Yadong, Xu, Min

Dimensional Optimization of Key Parameters Using DoE Technique to Achieve Better NO _X Emission Values in Mass Production of Single Cylinder Small Diesel Engines for 3 Wheeler Applications

2020-01-13564/14/2020

Oxides of Nitrogen (NOx) emissions are considered as among the most harmful emissions globally having a direct influence on human beings and the environment. This work deals with a strategy to arrive at achieving lower NOx values consistently in mass production of single cylinder automotive diesel engines meeting BS IV Emission standards using the DoE technique for dimensional optimization of critical parameters. Catalytic converters and particulate filters are mostly used as after - treatment devices for compression Ignition (CI) engines for bringing down the limits (Values) of the pollutants from the tail pipes. But the real ingenuity lies in achieving the same effect through optimization of in - cylinder combustion. Optimization of the critical factors like Nozzle Tip Protrusion (NTP), Static Injection Timing (SIT), Bumping Clearance (BC) and Swirl Number (SN) are considered as the most important engine design parameters for ensuring the optimum combustion which help release of minimal harmful pollutants. In this work, a standard L9 Orthogonal Array (OA) table was used in designing experiments for a study of the interactive model between the said factors and their levels to achieve consistently lower NOx emission values. The design specification of NTP considering the tolerance limit was set between 3.0 mm to 3.30 mm and similarly SIT, BC and Swirl value were set between 0.19 mm to 0.27mm, 0.65mm to 0.75 mm and 2700 rpm to 2800 rpm respectively. Tests were conducted on the basis of standard OA table and the corresponding NOx emissions were measured. It is found that, NTP of 3.2 mm, SIT of 0.19 mm, BC of 0.70 mm and Swirl Rate of 2775 rpm were seen yielding the least NOx emissions. Statistical observations showed the above mentioned combination exhibiting a reduction of NOX achieved with respect to the design specification as 22% and the variation of NOx between engines as 1.1%.

Ramalingam, Jaganathan, B, Prabakaran, Nandagopal, Sasikumar, Venkatesan, Hariram, Mayakrishnan, Jaikumar

Starting Process Control of a 2-Cylinder PFI Gasoline Engine for Range Extender

2020-01-03154/14/2020

With the increasing worldwide concern on environmental pollution, battery electrical vehicles (BEV) have attracted a lot attention. However, it still couldn’t satisfy the market requirements because of the low battery power density, high cost and long charging time. The range-extended electrical vehicle (REEV) got more attention because it could avoid the mileage anxiety of the BEVs with lower cost and potentially higher efficiency. When internal combustion engine (ICE) works as the power source of range extender (RE) for REEV, its NVH, emissions in starting process need to be optimized. In this paper, a 2-cylinder PFI gasoline engine and a permanent magnet synchronous motor (PMSM) are coaxially connected. Meanwhile, batteries and load systems were equipped. The RE co-control system was developed based on Compact RIO (Compact Reconfigurable IO), Labview and motor control unit (MCU). Focused on the starting process, the effects of first firing speeds, throttle control strategies and coolant temperatures were tested. The results show that the higher first firing speed is preferred without obvious torque fluctuation, and longer throttle switching duration to high load results in lower HC emissions. But the compromised duration for the engine in this paper is 5s.

Li, Minglong, Zhang, Ran, Zeng, Xingyu, Ding, Weiqi, Mao, Weiang, Jin, Shaoye, Xu, Rufeng, Yuan, Dengke, Hu, Zongjie, Zhong, Zaimin, Li, Liguang

An Investigation of the Effects of the Piston Bowl Geometries of a Heavy-Duty Engine on Performance and Emissions Using Direct Dual Fuel Stratification Strategy, and Proposing Two New Piston Profiles

03-13-03-00213/16/2020

Direct dual fuel stratification (DDFS) strategy benefits the advantages of the RCCI and PPC strategies simultaneously. DDFS has improved control over the heat release rate, by injecting a considerable amount of fuel near TDC, compared to RCCI. In addition, the third injection (near TDC) is diffusion-limited. Consequently, piston bowl geometry directly affects the formation of emissions. The modified piston geometry was developed and optimized for RCCI by previous scholars. Since all DDFS experimental tests were performed with the modified piston profile, the other piston profiles need to be investigated for this strategy. In this article, first, a comparative study between the three conventional piston profiles, including the modified, stock, and scaled pistons, was performed. Afterward, the gasoline injector position was shifted to the head cylinder center for the stock piston. NOX emissions were improved; however, soot was increased slightly. The other emissions, in-cylinder pressure, and AHRR remained unchanged. Finally, the advantages of modified and stock pistons were combined, and two new piston profiles based on the effective geometrical parameters were proposed and investigated. The first-proposed piston profile offered better NOX and CO emissions compared to the other profiles. In addition, the gross thermal efficiency of this profile is at high levels.

Shirvani, Sasan, Shirvani, Saeid, Shamekhi, Amir H., Reitz, Rolf D.

Ignition System Nomenclature and Terminology

J139_202002 (Current)2/10/2020

To provide standard terminology and definitions with regard to ignition systems for spark-ignited internal combustion engines.

Ignition Standards Committee

Isuzu dual-fuel system simplifies fuel changeovers

20TOFHP02_092/1/2020

Isuzu is making it easier for equipment owners to switch fuels from natural gas to liquid propane, letting users switch by merely sending a signal to the engine. Released in October 2019, the dual-fuel 4HV1 engines and power units also have a higher compression ratio that helps conserve fuel. The alternative fuel engines, designed for non-emergency and emergency standby generator applications and multi-speed applications, let operators switch fuel sources without reconfiguring the base engine. This feature helps to reduce downtime on site, according to Isuzu, which plans to feature the dual-fuel system at ConExpo-Con/Agg in March (South Hall 4, S85406).

Costlow, Terry

Study on the decision process of basic specification in development of general purpose engine

2019-32-05801/24/2020

Social interest in global environmental issues has remained in the forefront during recent years, and as a result, internal combustion engines are expected to have further improved fuel efficiency and reduced exhaust emissions. General purpose engines are demanded for reduced cost in addition to various types of displacement developments. If optimum specifications are examined for each engine displacement and incorporated in the parts shapes, the number of dedicated parts for each engine displacement would increase, which is not desirable from a development/production cost-wise standpoint. It is considered important during the development of engines to efficiently and economically cope with market needs including improved specific power and fuel consumption. Therefore, it was considered necessary to improve combustion performance by enhanced in-cylinder flow and to commonize parts. Then, this study was designed to establish an approach for decision of engine specifications with the perspective of multiple displacement development after satisfying the target performance by combustion improvement. The long stroke and valve angle were adjusted so as to examine specifications that enable enhanced in-cylinder flow with multiple displacements. By confirming that combustion characteristic and fuel efficiency characteristic are correlated to turbulence intensity in cylinder as well as by focusing on Turbulent Kinetic Energy and stroke/bore ratio, engine specifications satisfying the target performance with multiple engine displacements was decided. By making stroke common, it has become possible configure engines of various displacements that satisfy the target performance while achieving reduction of the total number of parts and cost reduction. As a result of verification of the decided specifications by using prototype engines, it was found that the improvement of specific power and fuel efficiency was achieved in comparison to the base engine.

Aoki, Takayuki, Tsuchiyama, Takahiro

Sensor Integrated Substrate for Future Exhaust System of Two Wheelers

2019-32-06171/24/2020

By upcoming new global two wheelers emission legislation, it is expected that it will become more and more challenging to control exhaust emissions. Therefore, not only optimized catalyst specifications to meet OBDII or RDE, but also new components will be required for future applications in two-wheeler exhaust systems. In such applications, beneath applying new components, it is necessary to ensure mountability while maintaining vehicle design but improving function of the exhaust system at the same time. As exhaust system layout of two wheelers is generally strongly limited by many factors, such as steeply bended exhaust pipes and catalysts which are hard to resize, one of the most challenging tasks is the positioning of sensor behind the catalyst, due to two wheelers unique exhaust design. In order to overcome the challenge, this work describes designs like the catalyst with integrated lambda sensor, which is developed to contribute to high efficient future two wheelers exhaust systems.

ITO, KOSAKU, SEIFERT, SVEN, JAYAT, FRANCOIS, CARTUS, THOMAS

Study on Robust Fuel Performance with Differing Fuel Types in a 2-Stroke CAI Combustion Engine

2019-32-0573

1/24/2020

This study sought to achieve robust combustion with the differing fuel types and levels of fuel quality that are present in various areas of the world. The tests used the 2-stroke controlled auto ignition (CAI) engine from our earlier report [1], which was proven to have potential as an efficient, clean engine for diesel fuel. This study verified whether efficient, clean CAI combustion of gasoline fuel could be achieved with the same basic structure and engine system. Diesel and gasoline have very different volatility, viscosity and ignition characteristics, all of which significantly affect combustion in an engine. It is particularly necessary in CAI combustion to adjust the ignition timing according to the fuel used, as the difference in auto-ignition temperature from gasoline and diesel affects the CAI ignition timing. This issue was addressed by conducting experiments with a test engine to determine how the ignition timing is affected by the equivalent ratio, compression ratio and in-cylinder flow, and the ideal solution was verified. The results indicated that the ignition timing for CAI combustion can be effectively adjusted by changing the shape of the scavenging port to alter the in-cylinder flow. Computational fluid dynamics (CFD) analysis confirmed that the change in the scavenging port shape increased the in-cylinder flow velocity and the turbulence kinetic energy at the compression end. This indicates that the in-cylinder flow during the compression stroke affects the ignition timing for CAI combustion. The results produced by this study also indicated that equivalent thermal efficiency and emission levels can be achieved for both diesel and gasoline by setting an appropriate equivalent ratio, compression ratio, in-cylinder flow and exhaust valve lift profile for each type of fuel. In conclusion, this study confirmed that 2-stroke CAI is a combustion process with extremely robust fuel performance and the potential to be suitable for various fuel types with significantly different properties.

Kurata, Mashu, Okubo, Masami, Yamada, Yoshikazu, Kitano, Sho

The Combustion Characteristic of Fuel Additives with Diesel–Ethanol Fuel blends on Engine Performance

2019-32-0611

1/24/2020

Reducing carbon dioxide (greenhouse gas) is one of the most important drivers to promote biofuels. Fuel from biomass has the potential to reduce greenhouse gas emissions and can gradually reduce the dependence on fossil fuels. However, fuel properties can differ significantly from standard diesel fuel and this will affect exhaust emissions and environmental pollution. Diesel – ethanol fuel blends development and specification are currently driven by the engine technology, existing fossil fuel specification and availability of feedstock. Thus, the aims of this study to investigate the effects of fuel additives with diesel–ethanol fuel blend under steady-state conditions. In the present study, the additives were palm diesel, n-butanol, ethyl acetate and di-tert-butyl peroxide (DTBP). The ratio of conventional diesel fuel to ethanol fuel to fuel additive are 80:15:5 by volume of fuel blends. The comparative studies on the effects of fuel additives in the engine performance and phase separation in diesel–ethanol blends. The effects of engine performance included exhaust gas emissions with different fuel additives on small diesel engine are also investigated under different engine conditions in order to considering the engine speed and engine load comparison with conventional diesel. The study found that all the additives are enhanced the stabilities in diesel–ethanol fuel blends and phase separation has not be found under the room temperature. The diesel–ethanol fuel blend with DTBP can improved the highest thermal efficiency with lower exhaust gas emission (e.g. carbon-monoxide, oxides of nitrogen, and soot) compare with conventional diesel with another fuel additives. However, the break specific fuel consumption is higher (>4%) than conventional diesel which could be acceptable range. The results suggest that significant benefits can derive from the use of di-tert-butyl peroxide as fuel additive for diesel and ethanol fuel blends as the alternative fuel for compression ignition engine in terms of engine performance, exhaust gas emissions, after treatment system performance and environmental pollution in the near future.

Theinnoi, Kampanart, Sawatmongkhon, Boonlue, Wongchang, Thawatchai, Sukjit, Ekarong, Chuepeng, Sathaporn

Analysis of Cycle-to-Cycle Variation in a Port Injection Gasoline Engine by Simultaneous Measurement of Time Resolved PIV and PLIF

2019-32-05521/24/2020

Cycle-to-cycle variation (CCV) of combustion in low load operation is a factor that may cause various problems in engine operation. Variable valve timing and variable ignition timing are commonly used as a means to reduce this variation. However, due to mountability and cost constraints, these methods are not feasible for use in motorcycle engines. Therefore, development of an engine with minimal CCV without utilizing complicated mechanisms or electronic control is required. CCV of combustion may be caused by fluctuations in in-cylinder flow, air-fuel mixture, temperature, residual gas and ignition energy. In this study, the relationship between CCV of combustion, in-cylinder flow fluctuation and air-fuel mixture fluctuation was the primary focus. In order to evaluate in-cylinder flow fluctuation, Time Resolved Particle Image Velocimetry (TR-PIV) technique was utilized. In addition, Planar Laser Induced Fluorescence (PLIF) technique was used to measure spatial distribution of the mixture. These two visualization techniques were used together to measure continuous combustion cycles. The fluctuation of net IMEP can be explained by the fluctuation of Turbulence Kinetic Energy (TKE) and fuel concentration. In most cycles, net IMEP was correlated with TKE. In the remaining cycles, net IMEP was correlated with fuel concentration. The contribution of each factor towards net IMEP is to be discussed. It has been also confirmed that TKE fluctuation is caused by fluctuation in the tumble vortex structure, as shown in the authors' previous study [2] [13].

HARAMIISHI, Santa, WATANABE, Takahiro, IIDA, Minoru, HOKIMOTO, Satoshi, KUBOYAMA, Tatsuya, MORIYOSHI, Yasuo

Calcium in Oil Effects on Pre-ignition of Two-stroke Engine

2019-32-05791/24/2020

Investigations of the influence of calcium on pre-ignition in a two-stroke engine have shown that the lower the calcium concentration, the lower the frequency of pre-ignition. Pre-ignition problems can occur in small, air-cooled, two-stroke engines such as a chainsaw. In contrast, in a supercharged automobile engine, it has been reported that calcium, which is a detergent component in engine oil, causes low-speed pre-ignition. The oil for two-stroke engines also contains calcium and is mixed with the fuel and lubricated before being supplied to the combustion chamber. This makes, two-stroke engines more likely to be affected by oil components. Based on this, we investigated the influence of calcium on pre-ignition of a two-stroke engine. First, we investigated driving conditions in which pre-ignition is likely to occur, such as warming up the engine. Under this condition, oil with calcium concentrations ranging from 0 ppm to 1,500 ppm were tested at a mixing ratio of 2%. The results show that the lower the calcium concentration, the lower the incidence rate of pre-ignition. Which could also occur at 0 ppm. The incidence rate was 4.6% at 1,500 ppm and 2.3% at 0 ppm.

Eto, Kuniyoshi, Kihara, Masaki

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