Today, we are all strongly dependent on the correct functioning of technical systems. They fail, and we become vulnerable. Disruptions due to degradation or anomalous behavior can negatively impact safety, operations, and brand name, reducing the profitability of all elements of the value chain. This can be tolerated if the link between cause and effect is understood and remedied. Anomalous behavior, which indicates systems or subsystems not acting in accordance with design intent, is a much more serious problem. It includes unwanted system responses and faults whose root cause can’t be properly diagnosed, leading to costly, and sometimes unnecessary, component replacements. The title No Fault Found: The Search for the Root Cause was developed to propose solutions to this technical and business challenge, which has become less and less acceptable to the commercial aviation industry globally.
A vehicle gearbox serves for torque and speed conversion with help of rotating elements. Therefor the gearbox experiences periodic excitation forces with a fundamental frequency following the rotation frequency. These excitation forces give rise to corresponding periodic response signals, i.e. signals having content at the fundamental (rotational) frequency and its harmonics. Order analysis is an analysis technique which is used to extract these harmonic orders from the response signals. This article intends to use the order tracking analysis for gearbox fault diagnosis under variable speed conditions to compare between healthy and faulty cases by using order extraction. Finally, determine maximum Root Mean Square (RMS) as severity index.
Abstract Advancements in numerical weather prediction (NWP) models continue to enhance the quality of in-flight icing forecasts and diagnoses. When diagnosing current in-flight icing conditions, observational datasets are combined with NWP model output to form a more accurate representation of those conditions. Surface observations are heavily relied upon to identify cloud coverage and cloud base height above observing stations. One of the major challenges of using these point-based or otherwise limited observations of cloud properties is extending the influence of the observation to nearby points on the model grid. An alternate solution to the current method for incorporating these point-based observations into the in-flight icing diagnoses was developed. The basis for the new method is rooted in a concept borrowed from signal and image processing known as dithering.
This SAE Aerospace Information Report (AIR) is applicable to rotorcraft structural health monitoring (SHM) applications, both commercial and military, where end users are seeking guidance on the definition, development, integration, qualification, and certification of SHM technologies to achieve enhanced safety and reduced maintenance burden based on the lessons learned from existing Health and Usage Monitoring Systems (HUMS). While guidance on SHM business case analysis would be useful to the community, such guidance is beyond the scope of this AIR. For the purpose of this document, SHM is defined as “the process of acquiring and analyzing data from on-board sensors to evaluate the health of a structure.” The suite of on-board sensors could include any presently installed aircraft sensors as well as new sensors to be defined in the future. Interrogation of the sensors could be done onboard during flight or using ground support equipment.
Historically SAE has been concerned with nomenclature as an integral part of the standards development process. Guidelines for automotive nomenclature were written in 1916, were last revised in 1941, and were included in the SAE Handbook until 1962. The present diversity of groups working on nomenclature in the various ground vehicle committees led to the organization of the Nomenclature Advisory Committee under SAE Automotive Council.
This Technical Information Report defines the General Motors UART Serial Data Communications Bus, commonly referred to as GM UART. This document should be used in conjunction with SAE J2534-2 in order to fully implement GM UART in an SAE J2534 interface. SAE J2534-1 includes requirements for an interface that can be used to program certain emission-related Electronic Control Units (ECU) as required by U.S. regulations, and SAE J2534-2 defines enhanced functionality required to program additional ECUs not mandated by current U.S. regulations. The purpose of this document is to specify the requirements necessary to implement GM UART in an aftermarket SAE J2534 interface intended for use by independent automotive service facilities to program GM UART ECUs in General Motors vehicles.
Diagnostic Coverage Evaluation Method for Analog Circuits to Comply with Functional Safety Standards
Abstract The ISO 26262 is a functional safety standard for road vehicles. The standard requires manufacturers to conduct quantitative assessment of the diagnostic coverage (DC) of products. The DC is defined as the percentage of failure probability covered by safety mechanisms. However, DC evaluation methods for drift faults, in which the change in element values is not constant, have not been discussed. In this paper, we propose a DC evaluation method for analog circuits with drift faults. With this method, we first parameterize the effect of drift faults onto a bounded region then split the region into safe fault, hazardous detectable fault, and hazardous undetectable fault regions. We evaluate the classification rate distribution by the area ratios of these regions.
Abstract Cavitation plays an important role in fuel injection systems. It alters the nozzle's internal flow structure and discharge coefficient, and also contributes to injector wear. Quantitatively measuring and mapping the cavitation vapor distribution in a fuel injector is difficult, as cavitation occurs on very short time and length scales. Optical measurements of transparent model nozzles can indicate the morphology of large-scale cavitation, but are generally limited by the substantial amount of scattering that occurs between vapor and liquid phases. These limitations can be overcome with x-ray diagnostics, as x-rays refract, scatter and absorb much more weakly from phase interfaces. Here, we present an overview of some recent developments in quantitative x-ray diagnostics for cavitating flows. Measurements were conducted at the Advanced Photon Source at Argonne National Laboratory, using a submerged plastic test nozzle.
Abstract Security access feature based on seed-key mechanism is widely used in automotive electronics, mainly for flashing ECU software, writing or reading specific parameter values and running diagnostic routines. There exist a number of techniques to decode the algorithm for key generation from a specific seed. Such techniques can put vehicle network at great risks due to an intruder flashing unauthorized version of ECU software, or changing internal parameters of ECU, or changing a VIN number. A lot more similar malicious attacks can be done by getting control over the ECUs. Attackers can exploit this vulnerability to alter the performance from the stock and affect the safety of the passengers. A novel and fool proof algorithm to protect the vehicle and ECU from such malicious attacks is explained in this paper. An advanced encryption technique is developed and tested in ECU to replace the current seed-key mechanisms for ECU security guarantying a secure operation of the vehicle.
Understanding the Effects of Fuel Type and Injection Conditions on Spray Evaporation Using Optical Diagnostics
Abstract Comparing with port-fuel-injection (PFI) engine, the fuel sprays in spark-ignition direct-injection (SIDI) engines play more important roles since they significantly influence the combustion stability, engine efficiency as well as emission formations. In order to design higher efficiency and cleaner engines, further research is needed to understand and optimize the fuel spray atomization and vaporization. This paper investigates the atomization and evaporation of n-pentane, gasoline and surrogate fuels sprays under realistic SIDI engine conditions. An optical diagnostic technique combining high-speed Mie scattering and Schlieren imaging has been applied to study the characteristics of liquid and vapor phases inside a constant volume chamber under various operating conditions. The effects of ambient temperature, fuel temperature, and fuel type on spray atomization and vaporization are analyzed by quantitative comparisons of spray characteristics.
Cycle Resolved Combustion and Pre-Ignition Diagnostic Employing Ion Current in a PFI Boosted SI Engine
Abstract An ion current sensor is employed in a 4 cylinder production SI engine for combustion diagnosis during combustion process, knock, and low speed pre-ignition (LSPI) detection. The results show that the ion current peak value and ion current peak phase have strong correlation with the cylinder pressure and pressure peak phase respectively. The COV of ion current integral value is greater than the COV of IMEP at the same operating condition. Results show that the ion current signal is sensitive to different lambdas. Using ion current signal, the knock in any given cylinder can be detected. Importantly, the ion sensor successfully detected the low speed pre-ignition (LSPI) about more than 20 °CA before spark ignition.
Cylinder by cylinder indicated torque and combustion feature estimation based on engine instantaneous speed and one cylinder pressure through error similarity analysis
Abstract There is increasing demand for engine diagnostic and control with in-cylinder pressure signal. However, the application of cylinder pressure sensors are restricted by the high cost of the sensor. Another possible way for engine combustion state estimation is by processing of instantaneous crankshaft speed signal, but it is limited by the precision and complexity of the algorithm. It could be a solution by processing one cylinder pressure signal in combination with a crankshaft speed signal. The indicated torque could be estimated through engine speed processing and also from the measure cylinder pressure for the reference cylinder. Measurement results from experiments show that the indicated torque error traces of different cylinder are similar in shape. According to this assumption, the reference cylinder with cylinder pressure signal available can serve as both a parameter calibration information source and an error reduction measure.
The purpose of this SAE Aerospace Information Report (AIR) is to provide information that would be useful to potential users/operators and decision makers for evaluating and quantifying the benefits of an Engine Monitoring Systems (EMS) versus its cost of implementation. This document presents excerpts from reports developed to analyze "actual aircraft cost/benefits results". These are presented as follows: a. First, to outline the benefits and cost elements pertaining to EMS that may be used in performing a cost versus benefits analysis. b. Second, to present considerations for use in conducting the analysis. c. Third, to provide examples of analyses and results as they relate to the user/operator and decision-maker community. The document encompasses helicopters and fixed wing aircraft and distinguishes between civilian and military considerations.
SAE J1979 / ISO 15031-5 set includes the communication between the vehicle's OBD systems and test equipment implemented across vehicles within the scope of the legislated emissions-related OBD.
This document supersedes SAE J1962 200204, and is technically equivalent to ISO/DIS 15031-3: December 14, 2001. This document is intended to satisfy the requirements of an OBD connector as required by U.S. On-Board Diagnostic (OBD) regulations. The diagnostic connection specified in this document consists of two mating connectors, the vehicle connector and the external test equipment connector. This document specifies: a. The functional requirements for the vehicle connector. These functional requirements are separated into four principal areas: connector location/access, connector design, connector contact allocation, and electrical requirements for connector and related electrical circuits, b. The functional requirements for the external test equipment connector. These functional requirements are separated into three principal areas: connector design, connector contact allocation, and electrical requirements for connector and related electrical circuits.
The purpose of this document is to specify the functional requirements for a miniature connector to be used for health monitoring purposes on aircrafts (including harsh environment such as the powerplant). It is actually a family of miniature connectors that is specified in this document for various uses (e.g. pin counts) and environments. This specification will be used by the SAE connector committee to work on a dedicated connector standard.
Rotary SI/CI combustion engines: A thing of the future? The internal combustion engine enjoys widespread use as an inexpensive and reliable power conversion system. While piston engines date back 150 years, various alternative engine architectures and cycles have been considered. Aftertreatment comes with challenging diagnosis Diagnosing engine and aftertreatment systems is forcing design teams to look at new ways to diagnose problems over long vehicle lifetimes. Taking on NVH reduction techniques A look at the enhanced durability benefits obtained by changing the polymer composition, manufacturing methods, and design optimization of a powertrain mount for an off-highway vehicle.
SAE J1939-75 Generator Sets and Industrial Applications defines the set of data parameters (SPNs) and messages (PGNs) for information predominantly associated with monitoring and control generators and driven equipment in electric power generation and industrial applications. Applications using the SAE J1939-75 document may need to reference SAE J1939-71 for the SAE J1939 parameters and messages for monitoring and controlling the power units, e.g. engines and turbines, that power the generators and driven industrial equipment.
This Technical Information Report defines the diagnostic communication protocol TP1.6. This document should be used in conjunction with SAE J2534-2 in order to fully implement the communication protocol in an SAE J2534 interface. Some Volkswagen of America and Audi of America vehicles are equipped with ECU(s), in which a TP1.6 proprietary diagnostic communication protocol is implemented. The purpose of this document is to specify the requirements necessary to implement the communication protocol in an SAE J2534 interface. This Technical Information Report describes how a tester can be connected to a vehicle to perform diagnostics using the TP1.6 protocol. Details regarding ECU to ECU communication have been left out.
The purpose of this SAE Information Report is to specify the requirements necessary to fully define the Serial Data Communication Interface (SCI) used in the reprogramming of emission-related powertrain Electronic Control Units (ECU) in Fiat Chrysler Automobiles (FCA) vehicles. It is intended to satisfy new regulations proposed by the federal U.S. Environmental Protection Agency (EPA) and California Air Resource Board (CARB) regulatory agencies regarding "pass-thru programming" of all On-Board Diagnostic (OBD) compliant emission-related powertrain devices. These requirements are necessary to provide independent automotive service organizations and after-market scan tool suppliers the ability to reprogram emission-related powertrain ECUs for all manufacturers of automotive vehicles. Specifically, this document details the SCI physical layer and SCI data link layer requirements necessary to establish communications between a diagnostic tester and an ECU.
Abstract The Selective Catalytic Reduction (SCR) system installed on the exhaust line is currently widely used on Diesel heavy-duty trucks and it is considered a promising technique for light and medium duty trucks, large passenger cars and off-highway vehicles, to fulfill future emission legislation. Some vehicles of these last categories, equipped with SCR, have been already put on the market, not only in the US, where the emission legislation on Diesel vehicles is more restrictive, but also in Europe, demonstrating to be already compliant with the upcoming Euro 6. Moreover, new and more stringent emission regulations and homologation cycles are being proposed all over the world, with a consequent rapidly increasing interest for this technology. As a matter of fact, a physical model of the Diesel Exhaust Fluid (DEF) supply system is very useful, not only during the product development phase, but also for the implementation of the on-board real-time controller.
Performance Requirements for R-134a and R-1234yf Refrigerant Diagnostic Identifiers (RDI) for Use with Mobile Air Conditioning Systems
This SAE Standard applies to refrigerant identification equipment to be used for identifying refrigerant HFC-134a (R-134a) and HFO-1234yf (R-1234yf) refrigerant when servicing a mobile A/C system or for identifying refrigerant in a container to be used to charge a mobile A/C system. Identification of other refrigerants is the option of the equipment manufacturer, although it shall not misidentify refrigerants, per 3.2.
The scope of the document is to define communication best practices in order to minimize problems for the vehicle owner when installing equipment which has a permanently or semi-permanently diagnostic communication device connected to the SAE J1962 connector or hardwired directly to the in-vehicle network.
Integrated Vehicle Health Management: Implementation and Lessons Learned is the fourth title in the IVHM series published by SAE International. This new book introduces a variety of case studies, lessons learned, and insights on what it really means to develop, implement, or manage an integrated system of systems. Integrated Vehicle Health Management: Implementation and Lessons Learned brings to the reader a wide set of hands-on stories, made possible by the contribution of twenty-three authors, who agreed to share their experience and wisdom on how new technologies are developed and put to work. This effort was again coordinated by Dr. Ian K. Jennions, Director of the IVHM Centre at Cranfield University (UK), and editor of the previous books in the series.
The ARP shall cover the objectives and activities of Verification & Vallidation Processes required to assure high quality and/or criticality level of an IVHM Systems and Software.
This document is intended to supplement SAE J2403 by providing the content of Table 1, Table 2, and Table 3 from SAE J2403 in a form that can be sorted and searched for easier use. It is NOT intended as a substitute for the actual document, and any discrepancies between this Digital Annex and the published SAE J2403 document must be resolved in favor of the published document. This document provides the content of Table 1 and Table 2 published in SAE J2403 into the single table in the 'Term' tab, while the 'Recommended Term Definitions' tab provides the content of Table 3 in SAE J2403 and the 'Glossary' tab provides the content of Table 4 in SAE J2403.
Abstract Alongside with the increasing vehicle complexity, the functionalities related to the safety, diagnosis and maintainability have become critical. The operators of special machines such as agricultural, mining, construction vehicles might be overwhelmed by this increased complexity and, as a result, operations for the recovery or maintenance of their vehicles become difficult. The Augmented Reality (AR) seems to be a very promising technology both if applied to traditional smart-phones or to the upcoming glasses, that has been just presented to the market by several manufacturers. This paper reviews some use cases of applications created in Institute for Agricultural and Earthmoving Machines (IMAMOTER) of the National research Council of Italy (CNR) engineers laboratories, which propose a novel approach for assisted maintenance, recovery or training.
This SAE Aerospace Information Report (AIR) examines the need for and the application of a power train usage metric that can be used to more accurately determine the TBO for helicopter transmissions. It provides a formula for the translation of the recorded torque history into mechanical usage. It provides examples of this process and recommends a way forward. This document of the SAE HM-1 IVHM Committee is not intended as a legal document and does not provide detailed implementation steps, but does address general implementation concerns and potential benefits.
Evaluation of Sensor Failure Detection, Identification and Accommodation (SFDIA) Performance Following Common-Mode Failures of Pitot Tubes
Abstract Recent catastrophic air crashes have shown that physical redundancy is not a foolproof option for failures on Air Data Systems (ADS) on an aircraft providing airspeed measurements. Since all the redundant sensors are subjected to the same environmental conditions in flight, a failure on one sensor could occur on the other sensors under certain conditions such as extreme weather; this class of failure is known in the literature as “common mode” failure. In this paper, different approaches to the problem of detection, identification and accommodation of failures on the Air Data System (ADS) of an aircraft are evaluated. This task can be divided into component tasks of equal criticality as Sensor Failure Detection and Identification (SFDI) and Sensor Failure Accommodation (SFA). Data from flight test experiments conducted using the WVU YF-22 unmanned research aircraft are used.
Aircraft Integration Challenges and Opportunities for Distributed Intelligent Control, Power, Thermal Management, Diagnostic and Prognostic Systems
Abstract Modern propulsion system designers face challenges that require that aircraft and engine manufacturers improve performance as well as reduce the life-cycle cost (LCC). These improvements will require a more efficient, more reliable, and more advanced propulsion system. The concept of smart components is built around actively controlling the engine and the aircraft to operate optimally. Usage of smart components intelligently increases efficiency and system safety throughout the flight envelope, all while meeting environmental challenges. This approach requires an integration and optimization, both at the local level and the system level, to reduce cost. Interactions between the various subsystems must be understood through the use of modeling and simulation. This is accomplished by starting with individual subsystem models and combining them into a complete system model. Hierarchical, decentralized control reduces cost and risk by enabling integration and modularity.