Browse Topic: Auxiliary power units

Items (677)

HELICOPTER TURBOSHAFT ENGINE IDLE POWER SCHEDULING

11/26/2025

The purpose of this AIR (Aerospace Information Report) is to provide aircraft and engine designers with a better understanding of helicopter turboshaft engine idle power characteristics and objectives to be considered in the design process. Idle is the lowest steady state power setting. At this setting, the engine typically does not produce enough power to obtain governed output shaft speed (i.e. the shaft speed is determined by the load imposed by the aircraft). In the aircraft, the engine is typically stabilized at this power setting after starting, prior to taxi and for some period of time after rotor shutdown for cool down prior to engine shutoff. Traditionally, the aircraft designer wants idle power scheduled as low as possible and of course, does not want any resulting aircraft operational difficulties such as overcoming the rotor brake. The engine designer, however, desires a higher scheduled power because of the reduced probability of engine operational problems. The attributes of conflicting idle desires are discussed. Other inputs are also considered to establish the engine idle power settings. The information contained herein will assist in the early design phase and ultimately will result in a more optimum match between engine and aircraft requirements.

S-12 Powered Lift Propulsion Committee

Gas Turbine Engine Lubricant Specifications: Current Technical Review and Future Direction

AIR6056A (Current)

11/26/2025

This AIR describes the current scientific and engineering principles of gas turbine lubricant performance testing per AS5780 and identifies gaps in our understanding of the technology to help the continuous improvement of this specification.

E-34 Propulsion Lubricants Committee

Guidelines for the Integration of Electronic Engine Control Systems for Transport Category (Part 25) and General Aviation (Part 23) Aircraft

AIR5924B (Current)

11/26/2025

This SAE Aerospace Information Report (AIR) provides methodologies and approaches that have been used to install and integrate full-authority-digital-engine-control (FADEC) systems on transport category aircraft. Although most of the information provided is based on turbofan engines installed on large commercial transports, many of the issues raised are equally applicable to corporate, general aviation, regional and commuter aircraft, and to military installations, particularly when commercial aircraft are employed by military users. The word “engine” is used to designate the aircraft propulsion system. The engine station designations used in this report are shown in Figure 1. Most of the material concerns an Electronic Engine Control (EEC) with its associated software, and its functional integration with the aircraft. However, the report also addresses the physical environment associated with the EEC and its associated wiring and sensors. Since most of today’s transport category engines use dual-channel full-authority digital engine control (FADEC) systems, this is the configuration which is addressed. A typical FADEC system configuration is shown in Figure 2.

E-36 Electronic Engine Controls Committee

Fluorescent Penetrant Inspection Aircraft Structures and Engine Component Maintenance

AMS2647G (Current)

9/20/2021

This specification details requirements and procedures for the detection of defects in aircraft structural and engine components during maintenance and overhaul operations.

AMS K Non Destructive Methods and Processes Committee

Electronic Engine Control Hardware Change Management

ARP6109A (Current)

6/22/2021

This document is intended for use by manufacturers of aircraft, engines and Electronic Engine Controls [EECs] as a component change process and evaluation guideline. Its purpose is to provide an effective means of managing the modification of electronic hardware. The process defined in this document is based upon: an understanding of the electronic component market evolution, e.g., obsolescence; lessons learned from the effects caused by the introduction of electrical component changes in a service fleet environment; industry best practice; and an understanding of the applicable regulations.

E-36 Electronic Engine Controls Committee

Procedure for the Continuous Sampling and Measurement of Non-Volatile Particulate Matter Emissions from Aircraft Turbine Engines

ARP6320A (Historical)

5/19/2021

This SAE Aerospace Recommended Practice (ARP) describes recommended sampling conditions, instrumentation, and procedures for the measurement of non-volatile particle number and mass concentrations from the exhaust of aircraft gas turbine engines. Procedures are included to estimate sampling system loss performance. This ARP is not intended for in-flight testing, nor does it apply to engines operating in the afterburning mode. This ARP is intended as a guide toward standard practice and is subject to change to keep pace with experience and technical advances.

E-31P Particulate Matter Committee

Performance Testing of Lubricant Filter Elements Utilized in Aircraft Power and Propulsion Lubrication Systems

AIR1666C (Current)

11/12/2020

This SAE Aerospace Information Report (AIR) reviews performance testing parameters for non-cleanable (often referred to as disposable) filter elements utilized in aircraft power and propulsion lubrication systems, including gas turbine engines and auxiliary power units (APUs), propulsion and transmission gear boxes, and constant speed drives and integrated drive generators (IDGs). This document is confined to laboratory testing of filter element performance to qualify the filtration medium and filter element construction as opposed to qualification of the complete filter assembly. The testing discussed here is usually followed by laboratory and on-engine testing of the entire lube filter assembly (including filter element, housing, valving, etc.), which is outside the scope of this AIR.

AE-5B Aircraft and Engine Fuel and Lubricant Sys Components

Aircraft Thermal Management System Engineering

AIR5744 (Current)

10/26/2020

The intent of this report is to encourage that the thermal management system architecture be designed from a global platform perspective. Separate procurements for air vehicle, propulsion system, and avionics have contributed to the development of aircraft that are sub-optimized from a thermal management viewpoint. In order to maximize the capabilities of the aircraft for mission performance and desired growth capability, overall system efficiency and effectiveness should be considered. This document provides general information about aircraft Thermal Management System Engineering (TMSE). The document also discusses approaches to processes and methodologies for validation and verification of thermal management system engineering. Thermal integration between the air vehicle, propulsion system, and avionics can be particularly important from a thermal management standpoint. Due to these factors, this report is written to encourage the development of a more comprehensive system engineering approach to help eliminate and/or reduce mission limitations as a result of materials and components nearing temperature limits.

AC-9 Aircraft Environmental Systems Committee

Test Cell Instrumentation

AIR5026B (Current)10/21/2020

This document discusses, in broad general terms, typical present instrumentation practice for post-overhaul gas turbine engine testing. Production engine testing and engine development work are outside the scope of this document as they will typically use many more channels of instrumentation, and in most cases will have requirements for measurements that are never made in post-overhaul testing, such as fan airflow measurements, or strain measurements on compressor blades. The specifications for each parameter to be measured, in terms of measurement range and measurement accuracy, are established by the engine manufacturers. Each test cell instrument system should meet or exceed those requirements. Furthermore, each instrument system should be recalibrated regularly, to ensure that it is still performing correctly.

EG-1E Gas Turbine Test Facilities and Equipment

Procedure for the Continuous Sampling and Measurement of Non-Volatile Particle Emissions from Aircraft Turbine Engines

AIR6241A (Current)

7/28/2020

This Aerospace Information Report (AIR) is a historical technical record describing procedures, required continuous sampling conditions, and instrumentation for the measurement of non-volatile particle number and mass concentrations from the exhaust of aircraft gas turbine engines. Procedures are included to calculate sampling loss performance. This AIR is not intended for in-flight testing, nor does it apply to engine operating in the afterburning mode. This Aerospace Information Report is a historical technical record of the initial document detailing the measurement of non-volatile particle emissions at the exit plane of aircraft gas turbine engines. This methodology was adopted by ICAO into Annex 16 Vol II and updated into Aerospace Recommended Practice ARP6320. Future updates of this document may include explanations of the reasoning and assumptions used to develop this measurement methodology.

E-31P Particulate Matter Committee

Using Design of Experiments to Size and Calibrate the Powertrain of Range-Extended Electric Vehicle

2020-01-08494/14/2020

A Range-Extended Electric Vehicle (REEV) usually has an auxiliary power source that can provide additional range when the main Rechargeable Energy Storage System (RESS) runs out. The range extender can be a fuel cell, a gas turbine, or an Internal Combustion Engine (ICE) bolted to a generator. Sizing the powertrain for a REEV is primarily to investigate the relationship between the capacity of the main RESS and the power rating of the range extender. Worldwide harmonized Light vehicles Test Procedures (WLTP) introduced a Utility Factor (UF) which is a curve used to calculate the weighted test results for the Off-Vehicle Charging-Hybrid Electric Vehicle (OVC-HEV) from the measured Charge Depleting (CD) mode range result, and the Charge Sustaining (CS) mode Fuel Consumption (FC). Therefore, the RESS capacity, the range extender power rating, the control strategy, and the UF are the key factors affecting the weighted FC of a REEV on the test cycle. The aim of this study is to demonstrate a fast approach to develop REEV powertrain concepts. It can size the capacity of the RESS (assumed electric battery for this paper), the power rating of the range extender and meanwhile consider the control strategy and the UF for a REEV, using simulation and Design of Experiments (DoE) tools. For the selected REEV powertrain, a DoE test matrix of the battery capacity, range extender power rating, and control strategy was created. The test cases were then imported into the simulation environment to perform the driving cycle simulations. After that, the simulation results (along with the UF) were used to calculate the weighted FC. Finally, a REEV weighted FC emulator model was created and interrogated using model visualisation and optimisation methods. Furthermore, the weighted FC’s calculated by using different regional Utility Factors were compared and discussed.

Bao, Ran, Baxter, James, Revereault, Pascal

Strategies to Gain the Loss in Power in a Military Diesel Engine Using JP-8 Instead of ULSD

2020-01-08044/14/2020

The Department of Defense (DOD) has adopted the use of JP-8 under the “single battlefield fuel” policy. Fuel properties of JP-8 which are different from ULSD include cetane number, density, heating value and compressibility (Bulk modulus). While JP8 has advantages compared to ULSD, related to storage, combustion and lower soot emissions, its use cause a drop in the peak power in some military diesel engines. The engines that has loss in power use the Hydraulically actuated Electronic Unit Injection (HEUI) fuel system. The paper explains in details the operation of HEUI including fuel delivery into the injector and its compression to the high injection pressure before its delivery in the combustion chamber. The effect of fuel compressibility on the volume of the fuel that is injected into the combustion chamber is explained in details. A fuel such as JP-8 which has a lower Bulk modulus is compressed to a smaller volume than ULSD which has a higher Bulk modulus before its delivery in the combustion chamber, and this is the main reason for the drop in power explained earlier. Experiments conducted on a CAT C7 engine demonstrated the loss in peak power associated with JP-8 over the whole speed range. Different approaches in the injection process have been discussed to gain the loss in peak power.

Raut, Prasad D., Atre, Omkar A., Trivedi, Manan, Henein, Naeim

Real Time Energy Management Control Strategies for an Electrically Supercharged Gasoline Hybrid Vehicle

2020-01-10094/14/2020

The high level of electric power available on a Hybrid Electric Vehicle (HEV) enables the introduction of electrical auxiliaries in addition or in substitution to the ones currently available on a conventional powertrain. Among these auxiliaries, electric Superchargers (eSC) for the improvement of the vehicle performance or electrically heated catalysts for the reduction of the light-off time of the after-treatment may dramatically affect the Energy Management System (EMS) of an HEV. Moreover, since these devices are only fluid-dynamically, but not mechanically, linked to the powertrain, they are traditionally neglected in the optimization of the powersplit between internal combustion engine and electric machines by the EMS. The aim of the current work is the development of an EMS that is able to consider in real time the overall electric energy consumption of the entire powertrain. More in detail, this activity focuses on the refinement of the Equivalent Consumption Minimization Strategy (ECMS) including the power required by an eSC installed on a turbocharged gasoline engine. This innovative EMS is tested by means of numerical simulation on a small SUV (Sport Utility Vehicle) featuring a 48 V electric network over Type Approval and Real Driving Emissions (RDE) driving cycles. The novel EMS shows promising results in terms of eSC energy management and vehicle fuel consumption compared with the baseline.

Accurso, Francesco, Zanelli, Alessandro, Rolando, Luciano, Millo, Federico

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

Fiber Optic Sensors for Aerospace Applications

AIR6258 (Current)1/30/2020

This document is intended to describe technologies available, application needs, and operational requirements relating to the use of fiber optic sensing systems on aerospace platforms: a To define standard terminology used in describing fiber optic sensing systems and their performance. b To identify current interfaces used for fiber optic sensing systems. c To define environmental, reliability, and maintainability capabilities of fiber optic sensing system components. d To describe the fiber optic sensor and instrumentation technologies that forms the current state of the art. e To describe current and future unmet needs of the aerospace industry for measurements using fiber optic sensors.

AS-3 Fiber Optics and Applied Photonics Committee

Aircraft Engine Technology Review - The Pathways for an Efficient, Cleaner and Quieter Aviation Industry

2019-36-01751/13/2020

The aviation industry has been submitted to a set of environmental and commercial drivers that have led it to pursue engine technologies focused on the efficiency improvement, greenhouse (CO2) and pollutant (NOx and PM) emissions reductions, as well as noise abatement.The effort to comply with the ambitious long term environmental and efficiency targets set by the regulatory authorities has driven the aeronautic industry in a technological research effort. In the medium term, the aviation industry's strategy for commercial aviation is to focus on the advanced, but rather conventional propulsion systems (mainly turbofan engines). In this scenario, technological efforts have focused basically on enhancing thermal efficiency, through advanced core engines, as well as improving propulsive efficiency, through the use of low pressure systems (basically reduced pressure ratio and increased engine bypass ratio). To reach these objectives, a set of technological platforms has been proposed, with some already on an operational/commercial level, while others still in a prototype category. In this context, engine manufacturers have given a special focus on some technological approaches, like Ultra High Bypass Ratio (UHBPR) Geared Turbofans (GTF), Three Spool Turbofan (3STF), Counter-Rotating Open Rotor (CROR), Intercooled Turbofan (ITF) and Bleedless Engine (BE). This work is supposed to present, into a review format, an overview of the aforementioned technology platforms, demonstrating their potential to meet the efficiency and environmental requirements, their maturity level, as well as report any cases of operational experience available in the technical literature.

Barbosa, Fábio Coelho

A Simulation Study for Hybrid Electric Vehicles with Gasoline Compression Ignition Technology

2019-01-221812/19/2019

Strict pollutants regulations, real driving emissions compliance and CO2 reduction mandates are stretching the boundaries of traditional internal combustion engine (ICE) development. Despite major improvements in the last decade, car manufacturers still face challenges in simultaneous abatement of CO2 and local emissions of conventional diesel compression ignition and gasoline spark ignition powertrains. By combining a clean fuel like gasoline with a high efficiency thermodynamic cycle (compression ignition) it is possible to create a powertrain that is clean both globally and locally, and so breaking the historical trade-off between decreasing CO2 vs. pollutants criteria. The concept is known worldwide as Gasoline Compression Ignition (GCI). Very low vehicle out CO2 cannot be achieved if ICEs are not combined with a hybrid electric powertrain. Saudi Aramco also looks into the possibility of combining GCI with hybrid electric technologies. A 0D simulation of powertrain was performed using the Stateflow® approach and Fuzzy Logic Toolbox™ in MATLAB® and Simulink® on different driving cycles. The purpose of this paper is to design the control strategies for different hybrid architectures based on certain parameters such as speed and torque, power demand and battery. Optimizing these parameters helped to achieve some significant results. So four hybrid architectures with variable battery sizes were optimized and simulated to prove the possibilities of CO2 benefits. The simulation results showed that a C-class vehicle equipped with a GCI engine and different hybrid powertrains can emit under 64g/km of CO2 like the target from European commission in 2030.

Won, Hyun-Woo

Auxiliary Power Take-off Drives for Agricultural Tractors

J717_201912 (Current)12/4/2019

This SAE Standard establishes specifications for mid- and side-power take-off drives that will be helpful in designing implements. Design of the implement attaching means must be tailored to each tractor, depending on attaching points available and the exact location of the auxiliary shaft.

Machine Technical Steering Committee

Test Method for Measuring Performance of Engine Cooling Fans

J1339_201909 (Current)9/30/2019

Cooling Systems Standards Committee

Flight Deck Lighting for Commercial Transport Aircraft

ARP4103A (Current)

9/17/2019

This document recommends design and performance criteria for aircraft lighting systems used to illuminate flight deck controls, luminous visual displays used for transfer of information, and flight deck background and instrument surfaces that form the flight deck visual environment. This document is for commercial transport aircraft except for applications requiring night vision compatibility.

A-20A Crew Station Lighting Committee

Safety Assessment of General Aviation Airplanes and Rotorcraft in Commercial Service

ARP5151A (Current)8/20/2019

This document describes a process that may be used to perform the ongoing safety assessment for (1) GAR aircraft and components (hereafter, aircraft), and (2) commercial operators of GAR aircraft. The process described herein is intended to support an overall safety management program. It is to help a company establish and meet its own internal standards. The process described herein identifies a systematic means, but not the only means, to assess continuing airworthiness. Ongoing safety management is an activity dedicated to assuring that risk is identified and properly eliminated or controlled. The safety management process includes both safety assessment and economic decision-making. While economic decision-making (factors related to scheduling, parts, and cost) is an integral part of the safety management process, this document addresses only the ongoing safety assessment process. This ongoing safety assessment process includes safety problem identification and corrective action, tracking of problems, the application of “lessons learned” to improve the efficiency of the process, and reduction of the time to achieve corrective action in the field. ARP5150 is the recommended practice for the safety assessment of Transport Airplanes in Commercial Service. ARP5151 is the recommended practice for the safety assessment process for GAR aircraft in commercial services. While the processes are similar, their implementations are different due to operations, data availability, and sizes of individual operations.

S-18C ARP5150A and ARP5151A Working Group

Response Surface Methodology (RSM) in Optimization of Performance and Exhaust Emissions of RON 97, RON 98, and RON 100 (Motor Gasoline) and AVGAS 100LL (Aviation Gasoline) in Lycoming O-320 Engine

03-12-04-00298/19/2019

Federal Aviation Administration (FAA)’s 20 years of research and development with 200 unleaded blends and full-scale engine tests on 45 high-octane unleaded blends has not found a “drop-in” unleaded replacement for aviation gasoline (AVGAS) 100 low lead (100LL) fuel. In this study, analysis of compatibility via optimization of Lycoming O-320 engine fuelled with RON 97, RON 98, RON 100, and AVGAS was conducted using the Response Surface Methodology (RSM). Test fuels were compositionally characterized based on Gas Chromatography (GC) analysis and were categorized based on types of Hydrocarbon (HC). Basic fuel properties of fuels in this research were analyzed and recorded. For optimization analysis, engine speed and fuel were considered as the input parameters. The output responses were Brake Horsepower (BHP), Brake Thermal Efficiency (BTHE), Brake-Specific Fuel Consumption (BSFC), Exhaust Gas Temperature (EGT), Carbon Dioxide (CO2), Carbon Monoxide (CO), HC, and Nitrogen Oxides (NOx). The engine speed (RPM) was varied at 2000-2700, and the fuels were varied at four (04) levels, RON 97, RON 98, RON 100, and AVGAS. The design matrix was selected based on one factor of RSM with 28 experimental runs. Analysis of Variance (ANOVA) was performed on the models. Values of “Prob > F” less than 0.05, differences between “predicted R2” and “adjusted R2” of less than 0.2, and “Adequate Precision” ratios greater than 4 were used to validate the significance of the model tested. Desirability approach was applied to measure the desirability function. Input parameters, engine speed and type of fuel set to be in range, BHP and BTHE were maximized while BSFC, EGT, and all emission responses were minimized. To confirm that the model can predict actual outcomes at the optimal settings determined from the analysis, confirmation test was carried out. Results indicated that when the engine was run with a speed of 2279.064 RPM, RON 97 fuel gave optimum solution of all tested fuels, and the corresponding values of BHP, BTHE, BSFC, EGT, CO2, CO, HC, and NOx were found to be 146.669 HP, 27.7%, 0.270 Kg/kW-hr, 382.008°C, 7.162%, 7.201%, 199.460 ppm, and 51.296 ppm, respectively, with a desirability index of 0.755. Results of this study indicate that lower octane fuels are favorable in this type of engine with lower compression ratio (CR). Matching engine design and fuel octane rating plays a significant and dominant role in the performance and exhaust emission.

Kumar, Thanikasalam, Mohsin, Rahmat, Majid, Zulkifli Abd., Ghafir, Muhammad Fahmi Abdul, Kim, Je Young, Wash, Ananth Manickam

Analysis of the Effect of Vehicle Platooning on the Optimal Control of a Heavy Duty Engine Thermal System

2019-01-12594/2/2019

One promising method for reducing fuel consumption and emissions, particularly in heavy duty trucks, is platooning. As the distance between vehicles decreases, the following vehicles will experience less aerodynamic drag on the front of the vehicle. However, reducing the velocity of the air contacting the front of the vehicle could have adverse effects on the temperature of the engine. To compensate for this effect, the energy consumption of the engine cooling system might increase, ultimately limiting the overall improvements obtained with platooning. Understanding the coupling between drag reduction and engine cooling load requirement is key for successfully implementing platooning strategies. Additionally, in a Connected and Automated Vehicle (CAV) environment, where information of the future engine load becomes available, the operation of the cooling system can be optimized in order to achieve the maximum fuel consumption reduction. In this paper, a control-oriented physics-based model for the engine cooling loop of a Volvo engine is developed and validated against road data. Starting from the validated model, an optimal control problem for the coolant system is formulated considering the tradeoff between the tracking of the engine temperature setpoint and the corresponding fuel consumption under different trailing distances. To compare the coolant system performance, Dynamic Programming (DP) is used to determine the global optimal solution for the coolant system actuator. The coupling between optimal cooling system operation and reduction in ram air are evaluated by comparing the results obtained from the DP under different platooning conditions against the unrestricted scenario. In addition, the paper analyzes the changes in the tradeoff between fuel consumption and setpoint tracking for different vehicle distances. This analysis will provide useful insight on the sensitivity of the coolant system controller calibration to the platoon distance.

Block, Brian, Huynh, Brian, Boyle, Stephen, Stockar, Stephanie, Geyer, Stephen, Li, Jian, Huber, Jeffrey

VW's MEB platform: a modularity enabler

19AUTP04_124/1/2019

Volkswagen's MEB, an in-development chassis designed strictly for electric propulsion, enables a modular battery layout that can provide a Volkswagen Group electric vehicle (EV) with an estimated 200-mile to 300-mile (322-km to 483-km) driving range. Slated to debut in 2022 as the underpinnings for EVs produced in North America at the automaker's Chattanooga, Tennessee assembly plant, VW's MEB is intended for compact to midsize A- and B-class vehicles. “What we're investing in with MEB is a dedicated platform for electric vehicles to achieve packaging efficiency, more cabin space and more energy,” Matthew Renna, Vice President of the E-Mobility Product Line for Volkswagen North American Region, said during a recent MEB workshop for media in Chicago.

Buchholz, Kami

Thermal Analysis of Aircraft Auxiliary Power Unit: Application of Chemical Looping Combustion

2019-01-13903/19/2019

An “APU” (Auxiliary Power Unit) is a small gas turbine engine to provide supplementary power to an aircraft and is located at the tails of larger jets. APU generators provide auxiliary electrical power for running aircraft systems on the ground. Applications include powering environmental systems for pre-cooling or preheating the cabin, and providing power for crew functions such as preflight, cabin cleanup, and galley (kitchen) operation and long-haul airliners must be started using pneumatic power of APU compressor. The Honeywell 131-9A gas turbine APU has 440 kW shaft power and 90 kW electric generator consuming 120 kg fuel/hour. Here the traditional combustor of the APU is proposed to be replaced by a chemical-looping-combustion (CLC) system. CLC system consist of two reactor one is oxidation reactor (air reactor) and the other is reduction reactor (fuel reactor).The system is fluidized bed system in which activated metal-oxide(MeO) participates and circulates between the reactors .The metal-oxide (MeO) provides oxygen for combustion in the fuel reactor. The reduced metal is then transferred to air reactor before being reintroduced to the fuel reactor to complete the process. In this process isolation of fuel from air simplifies chemical reaction related to combustion and using oxygen without nitrogen tends to eliminate formation of NOx from flue gases which is basically CO2 and water vapor. The proposed APU gas turbine with CLC combustion is expected to revolutionize aviation transportation as it is more eco-friendly. The maximum gas temperature at the exit of CLC is 1300K which is similar to maximum gas turbine cycle temperature hence the integration of CLC system to gas turbine APU is promising . Thermal analysis of the chemical looping combustion system is proposed to be reported. Also likely emission benefits from the proposed system would also be reported.

Kumar, Prashant, AKRAM, MD, Singh, Anand Shankar, S, Sanjay

Procedure for the Calculation of Non-Volatile Particulate Matter Sampling and Measurement System Losses and System Loss Correction Factors

ARP6481 (Historical)

2/25/2019

This SAE Aerospace Recommended Practice (ARP) details the recommended process for correcting measured non-volatile Particulate Matter (nvPM) mass and number data for particle losses in the sampling and measurement system specified in ARP6320. This technique is only recommended for conditions where both nvPM mass and number concentration measurements are in the valid measurement ranges of the instruments which are discussed in the tool limitations section. This ARP also supplies an Excel® software tool with documentation to automate the process. The body of the ARP details the recommended calculation method, uncertainties and limitations of the system loss correction factors. It explains, in detail, the required inputs and outputs from the supplied Excel® software tool (developed on Windows 7, Excel® 2016). Also included are: The Excel® correction tools (Attachments I and V). Installation instructions for a Windows based computer (Attachment II). A user technical manual (Attachment III) describing functions used within the tool and optional Excel® add-in (Attachment VI). Multiple Sample Test Cases (Attachment IV). The Excel® tools are intended to do the full calculation described in AIR6504. This ARP provides documentation for the Excel® spreadsheet system loss tool lite version (nvPM System Loss Tool v2_5_Lite.xlsm). The difference between the full tool and lite tool is described in Appendix C. Attachments III and VI are also described in Appendix C. If the user has produced her/his own software for the AIR6504 correction, comparison of results from this tool may be used to verify that software. This ARP does not contain the full description of the sampling and measurement system described in ARP6320. The correction technique is only briefly discussed in this ARP. More detailed information is provided in the AIR6054.

E-31P Particulate Matter Committee

Aircraft Exhaust Nonvolatile Particle Matter Measurement Method Development

AIR6037A (Current)11/20/2018

This report provides current practice measurement methods for quantifying nonvolatile particle matter at the exit plane of aircraft gas turbine engines. This document contains detailed information for many instruments and techniques, described in AIR5892A, that have been applied in aircraft engine field tests since AIR5892A was first issued in April 2003. There are four sections, identified as Technical Appendices (TA), presenting measurement techniques, sampling, and quantification of nonvolatile particles. The sections are written in the format of Aerospace Recommended Practice (ARP) documents and intended to progress to recommended practices upon overcoming existing technical challenges. Many important technical advances have been accomplished that comprise the Aircraft Engine Exhaust Nonvolatile Particle Matter Measurement Method Development techniques described in TA A: Particle Mass,TA B: particle Number and Size,TA C: Particle Sampling, and TA D: Calculation of Particle Number and particle Mass Emission Indices. Various measurement methodologies and operability and compatibility issues are described within the TAs. The TAs briefly discuss degrees of sensitivity, accuracy, repeatability, and test operations acceptability for each measurement discipline. They reflect that many important technical advances have been accomplished for measurement techniques of nonvolatile particles. Additional research is required to transition the TAs to Aerospace Recommended Practices.

E-31P Particulate Matter Committee

Environmental and Sustainability Aspects of an Aviation Auxiliary Power Unit Analyzed with the Aid of Exergy

2018-32-007110/30/2018

During the past decade environmental and sustainability issues have become major problems to overcome since they have caused regional and global consequences. This paper discusses the environmental and sustainability aspects of Gas Turbine (GT) based aviation Auxiliary Power Unit (APU) analyzed with the aid of exergy. Exergy analysis is a potential tool to determine exergy destructions and losses and their true magnitudes and exact locations. In this study some exergy based parameters such as: exergetic efficiency, waste exergy ratio, exergy recoverability ratio, exergy destruction ratio, environmental impact factor, and exergetic sustainability index are proposed and investigated. Cycle operating parameters such as compressor-pressure-ratio (rp,c), Turbine Inlet Temperature (TIT) have been chosen for analysis of the gas turbine cycle based APU. Mathematical modeling of the cycle has been done and the same has been coded in MATLAB. Results show that increasing waste exergy ratio decreases the exergetic efficiency and exergetic sustainability index. However, any increase in waste exergy ratio results in an increasing environmental impact of the GT cycle based APU. Exergetic efficiency, waste exergy ratio, exergy destruction ratio, environmental impact factor, and exergetic sustainability index are found to be 14.51%, 0.8549, 0.8349, 5.8917 and 0.16973 respectively for the overall cycle (rp,c= 3 and TIT =1300K). These results would be useful to make it more sustainable for future development.

Sahu, Aishi, Sahu, Mithilesh Kumar

Investigation of the Hybrid Operating Modes Regarding Efficiency, Emissions and Comfort for the Parallel-Series Hybrid Powertrain Concept DE-REX

2018-01-18289/10/2018

The “Two-Drive-Transmission with Range-Extender” (called DE-REX) is an innovative hybrid powertrain concept using two electric motors and an internal combustion engine. The two electric motors are permanent magnet synchronous motors with a maximum power of 48 kW each. As combustion engine a 3 cylinder, turbocharged engine with a power of 65 kW is used. The aggregates are coupled to a transmission whose layout is characterized by consisting of two parallel 2-speed sub-transmissions. This layout offers a high flexibility and enables both parallel and series hybrid driving. The hybrid control unit (HCU) has to select the optimal driving mode and power distribution between the aggregates in regard to in some extend competing objectives like efficiency, emissions or driving comfort. In particular, the operation of the internal combustion engine with only two gear ratios is challenging. In the course of the publically funded DE-REX project, the DE-REX powertrain concept was designed, manufactured and set up at an X-in-the-loop test rig. In this paper, the operating point decision is investigated in selected driving situations focusing at the conflict of objectives between the efficiency, the emissions of the combustion engine and the driving comfort. Therefore different hybrid control strategies are introduced on the basis of measurements at the powertrain test rig. Each strategy was designed to aim for one of the objectives gaining advantage out of the high flexibility of DE-REX. The availability of three propelling machines, gear selection and different hybrid modes opens up a wide field of driving power supply possibilities. The different strategy approaches show how an innovative powertrain design can improve system characteristics of modern hybrid vehicles.

Fischer, S., Viehmann, A., Beidl, C., Rinderknecht, S.

Exhaust Energy Recovery with Variable Geometry Turbine to Reduce Fuel Consumption for Microcars

2018-01-18259/10/2018

The objective proposed by EU to reduce by about 4%/year CO2 emission of internal combustion engines for the next years up to 2030, requires to increase the engine efficiency and accordingly improving the technology. In this framework, hybrid powertrains can have the possibility of a deep market penetration since they may recover energy during brake, allow the engine to operate in better efficiency conditions and with less transients, Moreover, they can recover a large amount of energy lost through the exhaust and use it to reduce fuel consumption. This paper concerns the modification of a conventional two in-line cylinders Diesel engine (440 cm3) adding a variable geometry turbine (VGT) coupled with a generator. The turbine is used to recover exhaust gas energy that otherwise would be lost. The generator, connected to the turbo shaft, converts mechanical energy into electrical energy and is used to charge the vehicle battery or the auxiliaries. The aim of this work is reducing fuel consumption by replacing the alternator with a kind of electric turbo-compounding system to drive vehicle auxiliaries. If the selected turbine recovers enough energy to power auxiliaries, the alternator, which usually has low efficiency, can be removed. Along these lines, fuel consumption savings can be achieved. At a later stage, a microcar has been tested on WLTC (Class 1) driving cycle. The results show fuel consumption reduction of 6 to 9%, depending on VGT size. Indeed, four different VGT sizes have been analyzed to choose the optimal configuration that reflects a compromise between energy recovery and fuel consumption reductions.

Ortenzi, Fernando, Genovese, Antonino, Carrazza, Martina, Rispoli, Franco, Venturini, Paolo

Air Quality for Commercial Aircraft Cabin Particulate Contaminants

AIR4766/1 (Current)8/23/2018

This SAE Aerospace Information Report (AIR) covers airbone particulate contaminants that may be present in commercial aircraft cabin air during operation. Discussions cover sources of contaminants, methods of control and design recommendations. Air quality, ventilation requirements and standards are also discussed.

AC-9 Aircraft Environmental Systems Committee

Auxiliary Power Solutions for 1500 VDC Photovoltaic Systems

TBMG-325068/1/2018

Photovoltaic systems are continually evolving to improve their efficiency and financial viability. One trend is to move to larger strings of cells giving higher dc voltages to be converted to ac voltage for the grid. Cost savings result, but auxiliary power supplies for monitoring and control need to accept these higher voltages as inputs.

Guide to Engine Lubrication System Monitoring

AIR1828C (Current)4/10/2018

This SAE Aerospace Information Report (AIR) provides information and guidance for the selection and use of technologies and methods for lubrication system monitoring of gas turbine aircraft engines. This AIR describes technologies and methods covering oil system performance monitoring, oil debris monitoring, and oil condition monitoring. Both on-aircraft and off-aircraft applications are presented. A higher-level view of lubrication system monitoring as part of an overall engine monitoring system (EMS), is discussed in ARP1587. The scope of this document is limited to those lubrication system monitoring, inspection and analysis methods and devices that can be considered appropriate for health monitoring and routine maintenance. This AIR is intended to be used as a technical guide. It is not intended to be used as a legal document or standard.

E-32 Aerospace Propulsion Systems Health Management

Review of Exhaust Gas Heat Recovery Mechanism for Internal Combustion Engine Using Thermoelectric Principle

2018-01-13634/3/2018

Automotive power packs have been the focus of research over a long period of time. Among various power packs when we consider internal combustion engines, there is an ample opportunity in developing systems that can make optimal utilization of all the energy streams related to the automotive engine. In this regard utilization of internal combustion engine exhaust waste heat and environmental pollution have been the focus of research in the recent past. About 35% of the automotive input fuel energy is converted to useful crankshaft work and about 30% energy is expelled with exhaust. This leaves about one-third (35%) of the total energy that must be transmitted from the enclosed cylinder through the cylinder walls and head to the surrounding. The exhausted energy from engine results in entropy elevation and solemn environmental pollution. So it is desired to utilize waste heat to the extent possible. The recuperation and utilization of waste heat not only conserves fuel but also additionally reduce the amount of waste heat and greenhouse gases dumped into environment. The objective of this study is to suggest waste heat recovery methods using thermoelectric generator which can be used to power various low energy consumption accessories of an automotive system. Thermo-electric generators are capable of enhancing the thermal efficiency of engines and can utilize the 35% of the exhaust gas stream energy efficiently.

Rathore, Souvik Singh, Singh, Anand, Kumar, Prashant, Alam, Nazish, Sahu, Mithilesh Kumar, R, Sanjay

Exergo-environmental Analysis of Basic and Intercooled-Recuperated Gas Turbine based Aviation Auxiliary Power Unit

2018-01-13764/3/2018

This paper deals with the exergo-environmental analysis of gas turbine with possible application as aviation auxiliary-power-unit (APU). The present work reports a comparison of thermodynamic performance, NOx and CO emission for basic gas turbine cycle (BGT) and intercooled-recuperated gas turbine (IcRcGT) cycle based engines for possible use by the aviation industry as auxiliary power unit (APU). In addition to this environmental sustainability index of these two cycles is also presented. Various cycle operating parameters such as compressor-pressure-ratio (rp,c), combustor-primary-zone-temperature, equivalence-ratio, and residence time have been chosen for analysis of the cycles. Mathematical modeling of the cycles has been done and the same have been coded in MATLAB. Results show that IcRcGT cycle exhibits higher gas turbine power output and gas turbine efficiency in comparison to BGT cycle for the same rp,c and turbine inlet temperature (TIT). Percentage exergy destruction for combustion chamber has been found to be lower for IcRcGT cycle as compared to BGT cycle. NOx and CO emission are higher in case of IcRcGT cycle as compared to BGT cycle. Adoption of the proposed scheme i.e. IcRcGT cycle based APU promises to deliver enhanced performance i.e. thermal efficiency of around 10.62 percentage points higher thermal efficiency as compared to traditional BGT based APU (rp,c = 2.6 and TIT = 1400K). Also for the proposed APU system, percentage exergy destruction for combustion chamber is reduced by around 14.95% and by 13.18% for the overall cycle (rp,c = 3.8 and TIT = 1300K). Also, IcRcGT cycle is more sustainable aviation APU technology as compared to BGT cycle.

Sahu, Aishi, Sahu, Mithilesh Kumar, R, Sanjay

Assessing a Hybrid Supercharged Engine for Diluted Combustion Using a Dynamic Drive Cycle Simulation

2018-01-09694/3/2018

This study uses full drive cycle simulation to compare the fuel consumption of a vehicle with a turbocharged (TC) engine to the same vehicle with an alternative boosting technology, namely, a hybrid supercharger, in which a planetary gear mechanism governs the power split to the supercharger between the crankshaft and a 48 V 5 kW electric motor. Conventional mechanically driven superchargers or electric superchargers have been proposed to improve the dynamic response of boosted engines, but their projected fuel efficiency benefit depends heavily on the engine transient response and driver/cycle aggressiveness. The fuel consumption benefits depend on the closed-loop engine responsiveness, the control tuning, and the torque reserve needed for each technology. To perform drive cycle analyses, a control strategy is designed that minimizes the boost reserve and employs high rates of combustion dilution via exhaust gas recirculation (EGR). The fully dynamic drive cycle results are compared to steady state (SS) GT-Power projections, using residence time spent in various SS operating points. The fuel consumption benefits enabled by the hybrid supercharger are simulated for the three standard drive cycles, FTP75, HWFET, and US06, and various drivers’ aggressiveness, showing a maximum of 5% improvement.

Nazari, Shima, Middleton, Robert, Sugimori, Kanji, Siegel, Jason, Stefanopoulou, Anna

Comparison of 1-D Modelling Approaches for Wankel Engine Performance Simulation and Initial Study of the Direct Injection Limitations

2018-01-14524/3/2018

Recent interest in the possible use of Wankel engines as range extenders for electric vehicles has prompted renewed investigations into the concept. While not presently used in the automotive industry, the type is well established in the unmanned aerial vehicles industry, and several innovative approaches to sealing and cooling have recently been developed which may result in improved performance for ground vehicle applications. One such UAV engine is the 225CS, a 225 cc/chamber single-rotor engine manufactured by Advanced Innovative Engineering (UK) Ltd. To be able to analyse the parameters, opportunities and limitations of this type of engine a model was created in the new dedicated Wankel modelling environment of AVL BOOST. For comparison a second model was created using the established method of modelling Wankel engines by specifying an ‘equivalent’ 3-cylinder 4-stroke reciprocating engine. The output from both of these models was evaluated using engine test data supplied by Advanced Innovative Engineering (UK) Ltd. The model created in the dedicated Wankel environment was found to fit the experimental data more closely. The model was then used to evaluate the impact on performance and fuel economy of applying direct injection to a Wankel rotary engine. This potential is because the nozzle can be situated in the cold side of the trochoid housing, taking advantage of the longer intake phase of the Wankel in turn permitting lower delivery pressures (the intake ‘stroke’ having 270 degrees of eccentric shaft rotation vs. 180 degrees for the reciprocating engine), plus the fact that the injector can be shielded from combustion pressure and hot burned gases. As it was found to be more accurate, the dedicated Wankel model was used to analyse the interrelationships between injector position, injection pressure and engine speed. Although a number of assumptions were required, and these will affect the accuracy of the model, the results provide a reasonable preliminary assessment of the feasibility of applying direct injection to the 225CS engine. A notable finding was that injection pressures of approximately 4.5 bar should be sufficient to supply fuel at all engine speeds and that the optimum position for the injector (for maximum fuel injection) corresponded to a position defined by the rotor apex tip at 597 degrees of eccentric shaft rotation after top dead centre firing. The advantage of both the injection pressure and injector location suggests a less complex fuel system design (compared to equivalent reciprocating systems) is possible at a reduced cost.

Peden, Michael, Turner, Matthew, Turner, James W G, Bailey, Nathan

Plain Bearings for Aerospace Applications

18AERP02_042/1/2018

Plain bearings are used across a wide range of aerospace applications to help achieve better fuel efficiency, extend maintenance intervals, and lower carbon emissions. These applications include installation in aircraft wing systems (flaps, spoilers, and slats), flight controls, cockpit controls, auxiliary power units, landing gear, door systems, and aircraft interiors (seats, bins, latches, and hinge points). “Our plain bearings even have a footprint on Mars,” said Brett Ricci, GGB Aerospace Strategic Account Manager for North America. “Operating in temperatures between −200°C to +280°C, our plain bearings have served as the primary suspension components in the robotic drilling arm of NASA's Curiosity Mars Rover since 2012.” Just as impressively, all of these applications are served by just two types of plain bearings: metal-polymer and fiber reinforced composite (FRC).

Plain Bearings for Aerospace Applications

TBMG-283932/1/2018

Plain bearings are used across a wide range of aerospace applications to help achieve better fuel efficiency, extend maintenance intervals, and lower carbon emissions. These applications include installation in aircraft wing systems (flaps, spoilers, and slats), flight controls, cockpit controls, auxiliary power units, landing gear, door systems, and aircraft interiors (seats, bins, latches, and hinge points). “Our plain bearings even have a footprint on Mars,” said Brett Ricci, GGB Aerospace Strategic Account Manager for North America. “Operating in temperatures between -200°C to +280°C, our plain bearings have served as the primary suspension components in the robotic drilling arm of NASA’s Curiosity Mars Rover since 2012.”

Procedure for the Continuous Sampling and Measurement of Non-Volatile Particulate Matter Emissions from Aircraft Turbine Engines

ARP6320 (Historical)

1/5/2018

E-31P Particulate Matter Committee

Penalties IN Performance of Three-Phase, Four-Wire, 400-Cycle Motors Caused by the Opening of One Phase

AIR34B (Current)11/30/2017

The scope of this SAE Aerospace Information Report (AIR) is to present a guide for the determination of probable power output and the effect on the aircraft system that will be experienced when operating three-phase motors with one phase open. Unfortunately, the above subject cannot be resolved by specific rules. Modern aircraft or missile electrical systems are composed of a wide variety of electrical and electronic components. These components react differently under identical impetus due to the latitude of their design. This latitude of design must be allowed wherever possible to the accessory designer due to the various specification requirements. Therefore, it cannot be over-emphasized that the effect on the airplane or missile system, as well as motor operation, of three-phase motors on two-phase power must be thoroughly investigated.

AE-7A Generators and Controls Motors and Magnetic Devices

SAE AE-7 High Temperature Components Survey, 2005

AIR5709A (Current)11/30/2017

To present the results of a survey taken concerning future applications for high-temperature electronics and sensors.

AE-7B Power Management, Distribution and Storage

Inlet Total-Pressure-Distortion Considerations for Gas-Turbine Engines

AIR1419C (Historical)

11/20/2017

This document addresses many of the significant issues associated with effects of inlet total-pressure distortion on turbine-engine performance and stability. It provides a review of the development of techniques used to assess engine stability margins in the presence of inlet total-pressure distortion. Specific performance and stability issues that are covered by this document include total-pressure recovery and turbulence effects and steady and dynamic inlet total-pressure distortion.

S-16 Turbine Engine Inlet Flow Distortion Committee

Potential of a Production DI Two-Stroke Engine Adapted for Range Extender and Motorcycle Applications

2017-32-008211/5/2017

The main purpose of this paper will be to investigate if a small snowmobile gasoline Direct Injected (DI) two-stroke engine has the potential to be adapted for two other types of applications: as a range extender (REX) for electric vehicles and for a motorcycle application. For the REX application, the main requested specifications (NVH, lightweight, compactness, minimum production cost and easy maintenance), correspond well to the main features of DI 2-stroke engines. The potential of a modified production engine operating in part load ultra-low NOx Controlled Auto Ignition (CAI) to meet the Euro 6 emissions standards on the NEDC cycle has already been demonstrated in a previous paper. In the first part of this new paper, we will investigate which solutions can be used to maintain this potential with even stricter legislations based on Euro 6d, WLTP cycle and Real Driving Emissions (RDE). In the second part of this paper, the feasibility of using the same production DI 2-stroke base engine for a motorcycle application will be studied. To meet the future Euro 4 and 5 motorcycle emissions standards on the new WMTC driving cycle, new combustion strategies have to be implemented. They are based on the use of CAI at part load and of the control of the air-fuel ratio at higher load combined with a 3-way catalyst aftertreatment technology. The encouraging results achieved show that such small DI 2-stroke engine could be a very attractive candidate for a low emissions motorcycle application as well as for a range extender application in an electric vehicle.

Duret, Pierre, Venturi, Stéphane, Sciarretta, Antonio, Foxhall, Nigel, Hinterberger, Walter

Nickel Cadmium Vented Rechargeable Aircraft Batteries (Non-Sealed, Maintainable Type)

AS8033 (Current)10/26/2017

The Nickel Cadmium battery covered by this Aerospace Standard is the type which is generally, although not exclusively, used for engine starting purposes in turbine-powered aircraft and/or on aircraft with turbine type Auxiliary Power Units. This turbine starting function requires high power delivery rates from the battery for 15 to 30 seconds or more for each engine start. This same battery may also be used at lower power delivery rates, as the final redundant source of emergency electrical energy for the operation of essential flight equipment for required periods of 30 to 60 minutes. The battery generally consists of a group of plastic jarred cells contained within an enclosing battery case. They are electrically connected in series with each other and usually terminate in an electrical connector mounted in the case front wall. The battery case may be secured to the aircraft structure by any of a number of clamping techniques. The outer or battery case is ventilated to purge it of gases, such as the hydrogen and oxygen produced in overcharge. This ventilation may be of the closed air circuit type which is accomplished by passing air through the case and then exhausting these gases overboard. An alternative method, which is used to purge these gases from the battery case, is to encourage their natural convective diffusion with the ambient air in the compartment which contains the battery, by use of relatively open construction of the battery case and cover. The battery, while in service, is generally charged by one of two methods: 1) by direct electrical connection to the D.C. bus which in turn is supplied by a regulated/controlled “constant potential” source such as a D.C. generator, or 2) from a dedicated “constant current” source in a system whereby the battery response voltage controls the termination, and also possibly the reinitiation, of that charge current. The “control” voltage of the “constant current” charge system or the regulated supply voltage of the “constant potential” system, may be compensated, or automatically adjusted, according to cell temperature, in order to more accurately control the state of “full charge” and minimize the amount of water used during overcharge. These batteries may be equipped internally with heaters, thermal switches, thermal sensors, etc. for performing various functions both inside the battery and/or in the aircraft/battery system. In addition, some battery types have air passages between cells with appropriate plenum chambers above and below the cells, for more positive responsive control of cell temperature, by the passage of conditioned air.

AE-7B Power Management, Distribution and Storage

Procedure for the Calculation of non-volatile Particulate Matter Sampling and Measurement System Penetration Functions and System Loss Correction Factors

AIR6504 (Current)

10/10/2017

This SAE Aerospace Information Report (AIR) describes a method for assessing size dependent particle losses in a sampling and measurement system of specified geometry utilizing the non-volatile PM (nvPM) mass and number concentrations measured at the end of the sampling system.1 The penetration functions of the sampling and measurement system may be determined either by measurement or by analytic computational methods. Loss mechanisms including thermophoretic (which has a very weak size dependence) and size dependent losses are considered in this method2 along with the uncertainties due to both measurement error and the assumptions of the method. The results of this system loss assessment allow development of estimated correction factors for nvPM mass and number concentrations to account for the system losses facilitating estimation of the nvPM mass and number at the engine exhaust nozzle exit plane. As the particle losses are size dependent, the magnitude of correction factors can vary as a function of many factors including combustor technology and engine operating condition. Implementation of the nvPM sampling and measurement system for aircraft engine testing, as per AIR6037, requires a sample line of up to 35 m and includes several sampling and measurement system components, which result in significant particle loss on the order of 50% for nvPM mass and 90% for nvPM number. The system loss correction factors are estimated based on a model with the following inputs and assumptions: engine exhaust exit plane nvPM have a lognormal distribution, known size dependent values of nvPM effective density and geometric standard deviation, a minimum particle size cut-off of 10 nm, and no coagulation.

E-31P Particulate Matter Committee