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Standard

Standard Requirements for Aerospace Organic Coatings Applicator Certification

2021-10-15
CURRENT
AS7489A
This standard establishes the minimum requirements for training, examination, and certification of aerospace coatings application personnel applying liquid organic coatings to interior structural or exterior substrates. It establishes criteria for the certification of personnel requiring appropriate knowledge of the technical principles underlying aircraft surface preparation and coatings application for both protective and decorative purposes. Persons who successfully complete the requirements of this certification standard are considered to be able to successfully and consistently perform a broad spectrum of aerospace coatings application tasks to achieve the desired engineering purposes. This certification is not intended to determine or replace any aerospace coating operation’s proprietary engineering for the depainting, preparation, or subsequent application of organic coatings materials to aircraft surfaces.
Technical Paper

Sensor-controlled Friction Materials based on Liquid Friction Compounds, Chip-in-Pad Concept

2021-10-11
2021-01-1296
In this paper, the concept of integrating thin-film piezo transducers into friction pads by using a liquid friction material compound (LIQFRIC® HP), which is capable of completely embedding the sensor surface and allowing for the force transfer due to a direct contact between sensor and friction material, is explained. The low thickness of the sensor allows for an excellent ratio of sensor volume / friction volume in the pad. The piezo transducer, besides being able to detect positive and negative pressure changes, can also be used via its EMI capability to allow measurements of changes in the shape (and therefore thickness) of the pad during and after testing. Measuring the pressure distribution, the wear and possible defect situations of the pad potentially opens up new means of friction pad- and brake operations or developments.
Standard

Defining and Measuring Factors Affecting Helicopter Turbine Engine Power Available

2021-10-01
CURRENT
ARP1702B
This SAE Aerospace Recommended Practice (ARP) identifies and defines a method of measuring those factors affecting installed power available for helicopter powerplants. These factors are installation losses, accessory power extraction, and operational effects. Accurate determination of these factors is vital in the calculation of helicopter performance as described in the RFM. It is intended that the methods presented herein prescribe and define each factor as well as an approach to measuring said factor. Only basic installations of turboshaft engines in helicopters are considered. Although the methods described may apply in principle to other configurations that lead to more complex installation losses, such as an inlet particle separator, inlet barrier filter (with or without a bypass system), or infrared suppressor, specialized or individual techniques may be required in these cases for the determination and definition of engine installation losses.
Technical Paper

Aerodynamic Performance Assessment on Typical SUV Car Model by On-Road Surface Pressure Mapping Method

2021-10-01
2021-28-0188
Aerodynamics of on-road vehicles has come to the limelight in the recent years. Better aerodynamic design of vehicle would improve vehicle fuel efficiency with increased acceleration performance. To obtain best aerodynamic body, the series of design modifications and different testing methodologies must be involved in vehicle design and validation phase. Wind tunnel aerodynamic force measurement, road load determination and computational fluid dynamics were the common methods used to evaluate the aerodynamic behavior of the vehicle body. As a novel approach, the present work discusses about the on-road (Real time) testing methodology that is aimed to evaluate the aerodynamic performance of vehicle body using surface pressure mapping. A 64-Channel digital pressure scanner has been utilized in this work for mapping the pressure at different locations of the typical vehicle body.
Technical Paper

Modelling of a Transient VCRS and Virtual Optimal Charge Determination for Automobiles

2021-10-01
2021-28-0255
Experimental research on the Vapor Compression Refrigeration System (VCRS) used in automobiles and other air conditioning systems is abundant in literature but it comes with inherent problems like the cost of the setup, time consumption, and tediousness of the process. Therefore, the objective of this study is to develop the fully-fledged transient or dynamic model of R134a based VCRS and further utilize it to virtually determine the optimal refrigerant charge quantity. The Simulink model developed in this work is an integration of physics-based mathematical models for each component (compressor, heat exchangers, and expansion valve), working together in a cycle where the compressor dictates the transient process. A sample simulation has been performed by taking 5 bar as the initial pressure of suction and discharge tanks and the steady state results (Discharge pressure, suction pressure, refrigerant mass flow rate, superheat and subcool temperatures) obtained.
Standard

Measurement of Minimum Noise Emitted by Road Vehicles

2021-09-26
WIP
J2889/1
This SAE Standard is derived from SAE J2805 and specifies an engineering method for measuring the sound emitted by M and N category road vehicles at standstill and low speed operating conditions.. The specifications reproduce the level of sound which is generated by the principal vehicle sound sources consistent with stationary and low speed vehicle operating conditions relevant for pedestrian safety. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The test method requires an acoustic environment which is only obtained in an extensive open space or in special designed indoor facilities replicating the conditions of an extensive open space. Such conditions usually exist during: • Measurements of vehicles for regulatory certification. • Measurements at the manufacturing stage. • Measurements at official testing stations.
Technical Paper

Off-Highway Machine Fuel Performance Prediction Through Engine Data Analytics

2021-09-22
2021-26-0319
The field performance of a machine is conventionally analyzed using tools of virtual validation such as physics-based simulation models. Machine performance test data is typically not incorporated for performance evaluation using these tools. The present work aims to demonstrate the use of Data Analytics (DA) as a tool to analyze this data for predictive purposes. It aims at establishing numerical relationships of engineering interest within the data, which would otherwise be complex if done only using physics-based models. Engine operation data spanning over three months, comprising of multiple channels, of an off-highway machine, is used for model development. Machine fuel burn rate is chosen as the dependent variable. Several independent variables such as engine speed, charge air pressure, NOx production level, are chosen based on their correlation with the dependent variable and upon engineering interest.
Technical Paper

“Real-Time Estimation of Soot for a Wall Flow DPF Regeneration Management and an Efficient DOE for Model Calibration.”

2021-09-22
2021-26-0333
Estimation of soot deposited on a wall flow type DPF, is a vital information to ensure safe and efficient DPF management. Accuracy in determining mass of soot present inside the DPF ensures a correct regeneration management strategy in-terms of fuel efficiency and DPF safety considering soot overloading and too frequent regenerations. It also ensures an efficient detection of anomalies in the PM filtration mandated by the BSVI/EURO VI legislation as a part of On-board diagnostics. Classical approach of determining soot present inside DPF involves monitoring increase in pressure drop. Real time usage of such a model is limited by the inaccuracy of measuring pressure drop at low exhaust flows. Hence, contemporary engine controllers use pressure drop based models as a failsafe and estimate DPF soot loading by modelling soot release rate due to engine combustion and the rate at which it is oxidized.
Technical Paper

Development of Compression Spring Variable Valve for Exhaust Mufflers

2021-09-22
2021-26-0289
The primary function of exhaust muffler is to reduce noise from the internal combustion engine without affecting its performance due to the impact of higher back pressure. The exhaust system back pressure is directly related to the engine fuel efficiency. The consumption of back pressure by the emission control system in BS IV regulation is about 30% from the total permissible engine limit, whereas in BS VI consumption is about 70%. The combination technologies used in BSVI and forthcoming RDE regulations such as TWC, GPF, DOC, DPF and SCR increases significant back pressure in exhaust system, hence the engine performance decreases. This demand robust method to control the exhaust back pressure for better fuel efficiency. Emission, noise and back pressure are the non-complimentary parameters in exhaust system development. The variable valve technology introduction in muffler is one method to optimize the above parameters.
Technical Paper

Effects of Ethanol-Blended Fuel on Combustion Characteristics, Gaseous and Particulate Emissions in Gasoline Direct Injection (GDI) Engines

2021-09-22
2021-26-0356
Ethanol fuel blends with gasoline for spark ignition (SI) internal combustion engines are widely used on account of their advantages in terms of fuel economy and emissions reduction potential. The focus of this paper is to study the effects of these blends on combustion characteristics such as in-cylinder pressure profiles, gas-phase emissions (e.g., unburned hydrocarbons, NOx) and particulates (e.g., particulate matter and particle number) using both measurement campaigns and digital engineering workflows. Nineteen load-speed operating points in a 1L 3-cylinder GDI SI engine were measured and modelled. The measurements for in-cylinder pressure and emissions were repeated at each operating point for three types of fuel: gasoline (E0, 0% by volume of ethanol blend), E10 (10 % by volume of ethanol blend) and E20 (20% by volume of ethanol blend).
Technical Paper

Application of Electromagnets in Windshield Wipers

2021-09-22
2021-26-0510
The most widely used type of windshield wiper system employs a coil spring for wiper arm pressure generation. This spring is fixed between the arm head (fixed part) and wiper arm (moving part) and the tension in the spring is responsible for pressure generation. The present arrangement although being unsophisticated design, has following drawbacks: Inability to change wiper arm pressure according to change in vehicle speed. Inability to provide constant arm pressure during the complete range of motion along varying curvature of windshield. Inability to reduce/remove the continuous pressure on wiper blade when vehicle is parked for long durations resulting in permanent deformation of wiper blade rubber. This paper describes how electromagnets can be used to overcome the above stated inherent limitations of the windshield wiper system. An electromagnet is a device which produces magnetic field on application of electric current.
Technical Paper

Aggressive Catalyst Heating Strategy Using Advanced Mixture Formation and Combustion Timing Techniques in a GDI Engine

2021-09-22
2021-26-0185
Precise control over mixture formation withhigh fuel pressure and multiple injections allows Gasoline Direct Injection (GDI) engines to be operated satisfactorily at extreme conditions wherePort Fuel Injection (PFI) engines wouldnormally struggle due to combustion instability issues. Catalyst heating phase is one such important condition which is initiated after a cold engine start to improve the effectiveness of the three-way catalyst (TWC). For a given TWC specification, fast light-offof TWC is achieved in the catalyst heating phase by increasing the exhaust gas temperature with higher exhaust mass flow. The duration of this phase must be as short as possible, as it is a trade-off between achieving sufficient TWC light off performance and fuel efficiency.
Technical Paper

Coastdown Road Load Coefficients of Passenger Vehicles - Variation Analysis and its Correlation with Temperature

2021-09-22
2021-26-0487
Road Load parameters (rolling resistance and aerodynamic drag) of a vehicle have strong impact on overall Vehicle Emissions and Fuel Economy. The road load coefficients are simulated on chassis dynamometer to carryout emission and fuel economy measurement and are hence required to be found beforehand. A realistic measure of road load parameters can be obtained by conducting a coastdown test. Coastdown test results are hugely impacted by various environmental parameters like ambient temperature, atmospheric pressure, wind speed etc. Though performed in standard boundary conditions, results of multiple tests performed on a vehicle vary from one another due to variations in the mentioned environmental parameters over and above standard test to test variation. This paper aims at studying the variation in test results due to ambient temperature as one of the parameters responsible.
Technical Paper

A Model Based Approach to DPF Soot Estimation and Validation for BSVI Commercial Vehicles in Context to Indian Driving Cycles

2021-09-22
2021-26-0183
With India achieving the BSVI milestone, the diesel particulate filter (DPF) has become an imperative component of a modern diesel engine. A DPF system is a device designed to trap soot from exhaust gas of the diesel engine and demands periodic regeneration events to oxidize the accumulated soot particles. The regeneration event is triggered either based on the soot mass limit of the filter or the delta pressure across it. For a Heavy Duty Diesel Engine (HDDE), pressure difference across the DPF is not usually reliable as the size of the DPF is large enough compared to the DPF used ina passenger vehicle diesel engine. Also, the pressure difference across DPF is a function of exhaust mass flow and thus it makes it difficult to make an accurate call for active regeneration. This demands for a very accurate soot estimation model and it plays a vital role in a successful regeneration event.
Technical Paper

A Study of Emission Durability and Ash Accumulation of “Advanced Three-way Catalyst Integrated on Gasoline Particulate Filter” for BS6 (Stage2) Applications

2021-09-22
2021-26-0182
India BS6 Stage2 (2023) regulations demand all gasoline direct injection (GDI) vehicles to meet particulate number emissions (PN) below 6x10+11# per km. Gasoline particulate filters (GPF) are a proven technology and enable high PN filtration efficiencies throughout the entire vehicle lifetime. One challenge for GPF applications could be the changing emission performance characteristics as a function of mileage due to collected ash and/or soot deposits with implications on back pressure losses. The main objective of this technical contribution is to study the above-mentioned challenges while applying Indian driving conditions and typical Indian climate and other ambient conditions. The substrate technology selected for this study is a high porosity GPF designed to enable the integration of a three-way functionality into the GPF, commonly described as catalyzed GPF (cGPF).
Technical Paper

Improvement in Drum-Brake Squeal Noise Prediction by Including the Effect of Brake-Liner Wear

2021-09-22
2021-26-0287
Drum brake squeal noise has been under investigation by automotive companies for decades due to consistent customer complaints and high warranty costs. Unstable natural frequencies of a brake system are closely linked with brake squeal noise. Complex eigenvalues are widely used to predict unstable frequencies of brake systems. Unstable frequencies are very sensitive to various system parameters such as vehicle speed, coefficient of friction, contact pressure distribution at the liner-drum interface, brake pressure, etc. In this paper, the author has focused on the brake pad wear effects on pressure distribution and eventually on the squeal noise propensity of a commercial vehicle drum-brake system. Wear at brake pads interface is simulated using simplified wear rate formula followed by complex eigenvalue analysis. Predicted unstable frequencies considering the effect of pad wear are found closer to the frequencies of measured noise in physical testing.
Technical Paper

Investigating Humidity Effects on Small Offroad Engine SI Performance and Emissions

2021-09-21
2021-01-1224
Collaborative research outlined in this paper documents recent engine and emission performance of a newer, more robust small SI engine across a sweeping range of relative humidity (RH) having fixed intake air temperature and pressure. The experimental results will show that power correction references to SAE J1349 as well as humidity correction (Kh) reference in EPA 40 CFR §1065 may generically be applied, but do not accurately compensate for the extent of correction required. The test results shared from this particular performance testing of a Kohler KT745 carbureted engine develops the case for a more diverse and less conservative approach to a one-size-fits all strategy related to humidity corrections within the small SI testing community. Moreover, humidity effects for both observed and corrected power, as well as emission corrected constituents (not just NOx) are generally greater than would otherwise be assumed from the literature.
Technical Paper

A Method for Determining the Bunsen Coefficient of Bio-Hybrid Fuels

2021-09-21
2021-01-1187
Since the amount of dissolved gas in fuels is an important quantity for the description of aeration in injection nozzles, this paper presents Bunsen absorption coefficients for different conventional and bio-hybrid fuels and their effect on nozzle flow phenomena. Bio-hybrid fuels can be produced both on the basis of biomass and with the help of regeneratively generated electrical energy. In contrast to previous work, the Bunsen coefficient was determined for a wide pressure range from approximately 10 MPa to 32.5 MPa. In fact, some of the fuels considered here were never before objects of investigation in terms of their solubility properties. In this work, large differences regarding the Bunsen absorption coefficient between a conventional fuel and a bio-hybrid fuel were observed. For determining the solubility of the fuels, a manometric-volumetric method was used.
Technical Paper

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

2021-09-21
2021-01-1190
Polyoxymethylene dimethyl ethers (OME) are promising alternative diesel fuels with a biogenic or electricity-based production, which offer carbon neutral mobility with internal combustion engines. Among other e-fuels, they stand out because of soot-free combustion, which resolves the trade-off between nitrogen oxide (NOx) and soot emissions. Additionally, long-chain OME have a high ignitability, indicated by a cetane number (CN) greater than 70. This opens up degrees of freedom in the injection strategy and enables simplifications compared to the operation with fossil diesel. This study investigates the hydraulic behavior of two solenoid injectors with different injector geometry for heavy-duty applications on an Injection Rate Analyzer (IRA) in diesel and OME operation. For OME, both injectors show longer injection delays in all injection pressure ranges investigated, increasing with rail pressure.
Standard

Minimum Operational and Maintenance Responsibilities for Aircraft Tire Usage

2021-09-20
CURRENT
ARP5265C
This SAE Aerospace Recommended Practice (ARP) sets forth criteria for the installation, inflation, inspection, and maintenance of aircraft tires and the maintenance of the operating environment to ensure the safety of support personnel and the safe operation of the aircraft.
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