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

AE-2 Lightning Committee

Basic Investigation of Thermodynamic Effects on a Hydrogen Two-Stroke Engine

2024-32-003904/18/2025

The spark ignited two-stroke engine, as a cost-efficient power unit with low maintenance demand, is used millionfold for the propulsion of hand-held application, motorcycles, scooters, boats and others. The outstanding power to weight ratio is the key advantage for two-stroke engines. However, poor exhaust emissions, caused by high scavenge losses, especially on port controlled two-stroke engines, and a low efficiency are disadvantages of this combustion process. Under the aspect of increasing environment- and health awareness, the two-stroke technology driven with fossil resources, shows no future advantage. The anthropogenic climate change force for sustainable development of combustion engines whereby reduction of fuel consumption or usage of alternative fuels is an important factor. Best way of a decarbonization to fulfil future climate goals is the utilization of non-carbon fuels. In this field of fuels, hydrogen, with its high energy content and close inexhaustible availability

Yasuda, Terutaka, Oswald, Roland, Kirchberger, Roland

Studying the Lean Burn Operation in Two-Wheelers to Increase Fuel Efficiency and Investigate the Use of Lean NOx Trap Catalyst (LNT) for Lean Burn System

2024-32-005804/18/2025

This study offers an overview of the impact of lean burn technology in two-wheeler vehicles, specifically concentrating on enhancing the fuel economy and addressing the challenges associated with its adoption. Lean burn systems, characterized by a fuel-air mixture with a higher air content than stoichiometric ratio. The study focuses on technology which meets stringent emission standards while enabling the optimization of fuel efficiency. The lean burn system employs strategies to optimize air-fuel ratio using electronic fuel injection, ignition timing control, and advanced engine control algorithms like - updated torque modulation control algorithm for drivability, lambda control algorithm for rich and lean switch and NOx modelling algorithm for LNT catalyst efficiency tracking. The challenges related to lean burn systems, includes issues related to combustion stability, nitrogen oxide (NOx) emissions, and their impact on drivability, is summarized in the study. Mitigation strategies

Somasundaram, Karthikeyan, Sivaji, Purushothaman, John Derin, C, Vishal, Karwa, Manoj Kumar, S, Maynal, Rajesh

Enhancements in Hydrogen Low Pressure Injection on Small Two-Stroke Engines

2024-32-004704/18/2025

The use of small 2-stroke crankcase scavenged engines running on hydrogen is very attractive for low power rates, when low cost and compact dimensions are the fundamental design constraints. However, achieving optimal performance with hydrogen fuel presents challenges, including uneven air-fuel mixtures, fuel losses, and crankcase backfiring. This research focuses on a small 50cc 2-stroke loop-scavenged engine equipped with a patented Low-Pressure Direct Injection (LPDI) system, modified for hydrogen use. Experimental results demonstrate performance comparable to the gasoline counterpart, but further optimizations are needed. Consequently, CFD-3D simulations are employed to analyses the injection process and guide engine development. The numerical analysis focuses on a fixed operating condition: 6000 rpm, Wide Open Throttle (WOT), with a slightly lean mixture and injection pressure fixed at 5 bar. A numerical model of the entire engine is set up with the primary objective of improving

Caprioli, Stefano, Schoegl, Oliver, Oswald, Roland, Kirchberger, Roland, Mattarelli, Enrico, Rinaldini, Carlo Alberto

Investigation on the Applicability of Passive Type Pre-Chamber with One Port Fuel Injection System to Small Gasoline Engines

2024-32-003304/18/2025

Pre-chamber combustion has been applied as a method of low fuel consumption in spark ignition engines, and in recent years the application of pre-chambers to gasoline engines has also been actively studied. In many gasoline engines, stoichiometric combustion is common. We decided that a passive type pre-chamber with only one port fuel injection is sufficient for stoichiometric combustion. The pre-chamber system relatively has two merits of lower cost and ease of installing than other prechamber systems. Therefore, we focused on investigating the effects of improving combustion speed and knock resistance in use of the passive type pre-chamber and the applicability of the pre-chamber system in various operating points. As the concrete approach, we evaluated the heat balance and the knock resistance with and without a pre-chamber in engine bench test. As a result, the knock resistance and the fuel consumption were improved. In addition, as a result of considering lean burn in the passive

Nakao, Yoshinori, Sakurai, Yota, Hisano, Atsushi, Saitou, Masahito, Suzuki, Tomoharu

Experimental Investigations of a Hydrogen Fueled Natural Gas Engine and Ion Current Measurement for Combustion Diagnostics in Pure Hydrogen Operationwith Water Injection

2024-32-006504/18/2025

In the ongoing effort to decarbonize energy supply, a notable shift involves the conversion or retrofitting of combined heat and power plants to operate on hydrogen as an alternative to natural gas. In this transformative landscape, extensive research is underway to develop and explore innovative combustion processes for hydrogen-fueled engines, aiming to comprehend and optimize combustion processes concerning both engine performance and emissions. Among the various methods available for monitoring the combustion process and engine control, ion current sensing presents itself as a viable option. A unique feature of this research lies in utilizing the engine's spark plug itself as an electrical sensor, measuring the ion current generated during the flame development and combustion processes. Given the limited research on ion current sensing for hydrogen combustion processes, a series of experiments were conducted and presented in this work. These experiments involved sweeps of water-to

Salim, Naqib, Beltaifa, Youssef, Kettner, Maurice, Loose, Oliver, Weißgerber, Tycho

Study on the Optimal Pre-Chamber Geometry for Active Pre-Chamber Gas Engines

2024-32-002304/18/2025

In a pre-chamber engine, fuel in the main-chamber is ignited and combusted by the combustion gas injected from the pre-chamber. Therefore, further fuel dilution is possible and thermal efficiency can be also improved. However, adding a pre-chamber to an engine increases the number of design parameters which have a significant impact on the main combustion and the exhaust gas. Then, in this study, the optimum geometry of the pre-chamber in an active pre-chamber gas engine was investigated. The considered parameters were the volume of pre-chamber, the diameter of a nozzle hole, and the number of nozzle holes. 18 types of pre-chambers with different geometries were prepared. Using these pre-chambers, engine experiments under steady conditions were conducted while changing the conditions such as engine speeds, mean indicated pressure and air excess ratio. Based on the experimental data, neural network models were constructed that predict thermal efficiency, NOx and CO emissions from the

Yasuda, Kotaro, Yamasaki, Yudai, Sako, Takahiro, Takashima, Yoshitane, Suzuki, Kenta

Statistical Analysis of Data Acquired from Propagating Flames in Gasoline Engines Using a Multiple Ion Probe

2024-32-003504/18/2025

Multiple-ion-probe method consists of multiple ion probes placed on the combustion chamber wall, where each individual ion probe detects flame contact and records the time of contact. From the recorded data, it is also possible to indirectly visualize the inside of the combustion chamber, for example, as a motion animation of moving flame front. In this study, a thirty-two ion probes were used to record flames propagating in a two-stroke gasoline engine. The experiment recorded the combustion state in the engine for about 3 seconds under full load at about 6500 rpm, and about 300 cycles were recorded in one experiment. Twelve experiments were conducted under the same experimental conditions, and a total of 4,164 cycles of signal data were obtained in the twelve experiments. Two types of analysis were performed on this data: statistical analysis and machine learning analysis using a linear regression model. Statistical analysis calculated the average flame detection time and standard

Yatsufusa, Tomoaki, Okahira, Takehiro, Nagashige, Kohei

Fuel Film Measurement in a SI Gasoline Engine Using a Newly Developed MEMS Sensor

2024-32-007104/18/2025

The previously developed capacitance sensor for detecting a liquid fuel film was modified to apply to the in-cylinder measurement. On the developed sensor surface, comb-shaped electrodes were circularly aligned. The capacitance between the electrodes varies with the liquid fuel film adhering. The capacitance variation between the electrodes on the sensor surface was converted to the frequency variation of the oscillation circuit. In the previous study, it was revealed that the frequency of the oscillation circuit varies with the variation of the liquid fuel coverage area on the sensor surface. The developed sensor was installed in the combustion chamber of the rapid compression and expansion machine, and the performance of the developed sensor was examined. Iso-octane was used as a test fuel to explore the sensor that had been developed. As a result, the adherence of the liquid fuel directly injected into the cylinder was successfully detected under the quiescent and motoring

Kuboyama, Tatsuya, Moriyoshi, Yasuo, Takayama, Satoshi, Nakabeppu, Osamu

Detailed Approach for Pre-Chamber Heat Release Analysis for the HSASI Pre-Chamber Spark Plug Using a Pressure Sensor Glow Plug

2024-32-006304/18/2025

The hot surface-assisted spark ignition (HSASI) pre-chamber spark plug, which was developed at the Karlsruhe University of Applied Sciences, increases the dilution limit with excess air and the tolerance to residual gas in the pre-chamber compared to a conventional passive pre-chamber spark plug. In this study, the conventional glow plug which is integrated in the pre-chamber of the HSASI pre-chamber spark plug was replaced by a pressure sensor glow plug (PSG) from BERU. This allows for a detailed combustion analysis in the pre-chamber. The signal of the PSG was validated with a piezoelectric cylinder pressure sensor and a method to analyse the pre-chamber heat release was introduced. Experimental investigations were carried out on a single-cylinder gasoline engine. A series of operating points diluted with excess air and a variation in load were conducted. The gas flow rate through the orifices of the pre-chamber was calculated from the pressure difference between the pre-chamber and

Holzberger, Sascha, Kettner, Maurice, Kirchberger, Roland

Effect of Ignition Position on Lean Limit of Main Chamber Combustion in Pre-Chamber Ignition

2024-32-002204/18/2025

An engine was built in this study that enabled the conditions in a pre-chamber and in the main combustion chamber to be visualized simultaneously for the purpose of elucidating the mechanism of pre-chamber combustion. An investigation was made of how the state of pre-chamber combustion, including the location of initial flame generation and its subsequent propagation, influenced pre-chamber jet combustion. The state of pre-chamber combustion was intentionally varied by changing the position of pre-chamber ignition. As a result, it was found that changing the position of pre-chamber ignition varied the location where the pre-chamber flame occurred, how the flame propagated and the timing and strength of the flame jet that was ejected into the main chamber. The results revealed that these differences in the state of pre-chamber combustion markedly changed the rate of combustion fluctuation, combustion period, lean-burn limit and other combustion characteristics depending on the ignition

Onuma, Takeru, Yamada, Hiroto, Ugajin, Taisei, Shinozaki, Kaito, Tahara, Ryota, Iijima, Akira

3D-CFD Simulations of H2 ICEs: A Preliminary Evaluation of a Laminar Flame Speed Correction for Thermo-Diffusive Instability

2024-32-007404/18/2025

In recent years, climate change and geopolitical instability have intensified the focus on sustainable power generation. This shift seeks alternatives that balance environmental impact, cost-effectiveness, and practicality. Specifically, in transportation and power generation, electric motors face challenges against internal combustion engines due to the high cost and mass of batteries required for energy storage. This makes electric solutions less favorable for these sectors. Conversely, internal combustion engines, when properly fueled, offer cost-effectiveness and a quasi-environmentally-neutral option. To address these challenges, researchers have explored e-fuels derived from renewable sources as a carbon-neutral supply for internal combustion engines. Among these, hydrogen is particularly promising. In hydrogen-powered internal combustion engines, 3D-CFD (Computational Fluid Dynamics) in-cylinder models are crucial. Once validated, these models can speed up the design process. A

Sfriso, Stefano, Berni, Fabio, Breda, Sebastiano, Fontanesi, Stefano, Cordisco, Ilario, Leite, Caio Ramalho, Brequigny, Pierre, Foucher, Fabrice

Enhancing Low Temperature Lean Combustion of CH4-H2 Blends through a Prechamber Equipped Engine

2024-32-004404/18/2025

The use of hydrogen as a sustainable fuel in the short term is hampered by the impossibility of large scale use due low availability. In order to promote decarbonization, complementary solution for a smooth transition is to dilute it in a mixture with methane, in a current Port Fuel Injection (PFI) internal combustion engine (ICE). This can be done as a retrofit after limited structural modifications, such as the introduction of a passive prechamber. Such a solution allows a reduction of the carbon footprint of traditional ICEs through more efficient combustion (both the prechamber technology and the hydrogen fuel properties promote an increase in combustion speed) and a reduced carbon content in the fuel. The present research activity has been carried out through numerical investigation based on three-dimensional CFD analyses to simulate the behavior of a natural gas engine fueled with CH4-H2 blends. The combustion mechanism for the fuel blend was validated against measurements of the

Balduzzi, Francesco, Ferrara, Giovanni, Di Iorio, Silvana, Sementa, Paolo

Experimental Investigation of n-C7H16/Ethanol Blended Fuels on Auto-ignition and Flame Propagation in High Temperature/Pressure Constant-Volume Combustion Vessel

2024-32-005004/18/2025

This study aims to investigate the effect of ethanol blends on flame propagation and auto-ignition under high pressure and high temperature conditions. Experimental investigations are conducted using n-C7H16 / ethanol blends at various blending ratios (0, 5, 10, 20, 40, 70, and 100 vol%). The blends are premixed with air at stoichiometric ratios and ignited centrally in a cylindrical constant-volume combustion chamber (20-mm inner diameter, 80-mm long) under elevated temperature (500 K) and pressure (1.0 MPa) conditions. The results show that auto-ignition occurs at an ethanol blend ratio of 10% or less and ceases above 20%. Increasing the ethanol blend to 70% results in a slight change in flame propagation speed, with a noticeable delay at 100%. The pressure measurements show a peak of about 5.6 MPa at a blend ratio of 5%, which gradually decreases with increasing ratios. High-pass filtering reveals the maximum pressure fluctuation amplitude at the 5% blend ratio, indicating increased

Tateishi, Tokua, Yamaguchi, Riki, Shimokuri, Daisuke, Terashima, Hiroshi, Hara, Takaya, Honda, Yuya, Kawano, Michiharu

Optimization of the Numerical Spray Modeling for Polyoxymethylene Dimethyl Ethers for Combustion Prediction in CONVERGE

2025-01-502604/03/2025

Different approaches are undertaken to mitigate the impact of the transport sector on climate change. Alongside electrifying powertrains, sustainable e-fuels such as polyoxymethylene dimethyl ethers (OME) are considered a promising bridging technology for different applications. However, this requires that the engines are optimized for the new fuels. Accordingly, this study aims to optimize the numerical spray modeling of OME in CONVERGE. Based on the KH–RT break-up model, the spray simulations of three different commercial injectors for heavy-duty applications are analyzed regarding the predictability of the liquid and gaseous penetration lengths and the total simulation time. A sensitivity analysis is conducted for the turbulence model, mesh size, and spray parameters prior to optimizing the spray model and validating it with experimental results. While each parameter individually influences the different phases of the injection event, the sensitivity analysis reveals that the break

Zepf, Andreas, Härtl, Martin, Jaensch, Malte

AFR Adaptation Strategy Based on Lambda Sensor for a Methanol Engine

2025-01-703901/31/2025

Methanol is an main type clean energy and it taken important part for the future internal combustion engine technology. The Equivalent air-fuel ratio (AFR) is very import for the engine combustion of methanol. And a lot of case the ratio between methanol and gasoline is not the constant number. There are no studies about AFR when fuel ratio is arbitrary in the currently. The AFR changes obviously if the tank was fueled with gasoline by mistake at a methanol spark ignition engine. Emission will be affected heavily at this situation because the AFR of gasoline is 2 times more than methanol. Some fuel trim adaptation error will be detected by engine controller or even the engine will stall if engine controller keep use the previous AFR to do the fuel injection control. The Investigation provide a relevant AFR adaption strategy based on lambda sensor and the fuel pipes configuration. The strategy was proved valid by some simulation cases to reduce lambda disturbance, optimize emission

Liu, Yiqiang, Zhong, Jun, Qian, Pengfei, Qiao, Zhiwei, Zhu, Delei, Zhong, Shuanglei, Dong, Yanzhao, Yu, Xiuju

Title

AIRS12242024 (Current)12/24/2024

A-20A Crew Station Lighting

Tight

AIR12122024A (Current)12/12/2024

New Scoop

A-6 Aerospace Actuation, Control and Fluid Power Systems

test

ARPTEST3008A (Current)12/12/2024

A-6 Aerospace Actuation, Control and Fluid Power Systems

AIR12092024 (Current)12/09/2024

A-6 Aerospace Actuation, Control and Fluid Power Systems

3D-Printed Reactor Core Makes Solar Fuel Production More Efficient

TBMG-5219312/01/2024

In recent years, engineers at ETH Zurich have developed the technology to produce liquid fuels from sunlight and air. In 2019, they demonstrated the entire thermochemical process chain under real conditions for the first time, in the middle of Zurich, on the roof of ETH Machine Laboratory. These synthetic solar fuels are carbon neutral because they release only as much CO2 during their combustion as was drawn from the air for their production. Two ETH spin-offs, Climeworks and Synhelion, are further developing and commercializing the technologies.

ACHIEVING 44% THERMAL EFFICIENCY in TODAY’S ENGINES “More for Less”

2024-01-3188

11/15/2024

ABSTRACT The US Army is seeking improvements in the fuel efficiency of their military vehicles.. They have initiated a number of R&D projects aimed at advancing the state-of-the-art of powertrain efficiency including demonstration in a laboratory environment. This effort will set a benchmark for the vehicle integrators, allowing them to improve future vehicle offerings. The SAIC, AVL, Badenoch, QinetiQ and Ker-Train Research team offered powertrain solutions from 7 Tons to 40 Tons that achieved the goal of 44% thermal efficiency and the stringent flexible fuel and emissions requirements. In each of these offerings the team was able to identify modifications to existing engines that allowed dramatic improvements in the thermal efficiency. These efficiency improvements were achieved through a combination of techniques, combustion cycle adjustments using in-cylinder pressure monitoring and precise control of fuel injector timing, and turbo-compounding. For the R&D project, the fuel

McDowell, Jim, Hunter, Gary L., Hennessy, Chris

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