Your Destination for Mobility Engineering Resources

This supplement forms a part of SAE Aerospace Specification AS85421. It shall be used to identify fitting standards citing this procurement specification.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
These days, the vehicle dynamics control of electric vehicles (EVs) with multi-actuated architectures has been widely investigated. Such EVs have a torque vectoring differential (TVD), which can generate a torque difference between the left and right wheels. As one of TVDs, a two-motor-torque difference amplification mechanism (TDA-TVD), has been proposed. The TDA-TVD can generate a greater torque difference compared to an individual-wheel-drive (IWD) system. However, it has controllability difficulties due to its two resonance modes. Previous studies first proposed a frequency response model of the TDA-TVD and anti-vibration feedforward torque controllers based on an average-differential coordinates (ADC) transformation. Subsequently, wheel speed control (WSC) and slip ratio control (SRC) based in the ADC were presented. However, only the WSC was designed with frequency domain analysis, and the SRC was designed with manual tuning. In this study, the closed loop of the SRC of the TDA
Fuse, HiroyukiFujimoto, HiroshiSawase, KaoruTakahashi, NaokiTakahashi, RyotaHayashi, Takayuki
In modern warfare, military control of the airspace determines aircraft survivability against the most widespread missile threats. The aero-engine exhaust system is an important source of infrared (IR) signatures from the rear aspect, particularly in the 2–3 μm and 3–5 μm IR bands. Two-dimensional (2D; non-axisymmetric) nozzle exits with high aspect ratio (AR > 5) are widely used in stealth aircraft engines due to their low IR signature, ease in thrust vectoring, and high maneuverability and agility. This analytical study compares the specific thrust (for choked and unchoked flow regimes) and the visible planar areas of a 2D nozzle exit with different ARs with those of a circular nozzle, as seen from the direct rear view. The nozzle’s isentropic efficiency (ηis,noz) is obtained in terms of the total pressure ratio, and the effect of AR on ηis,noz is examined for 1 ≤ AR ≤ 15. It is found that ηis,noz decreases with increasing AR, but this decrease is more rapid in unchoked flow than in
Baranwal, Nidhi
This paper reviews data fusion strategies for generating aerodynamic databases and evaluates their suitability for motorsport aeromaps, with emphasis on the operational constraints specific to Formula One. A structured survey and classification of the state of the art is presented, grouping approaches into (i) surrogate-agnostic methods, (ii) kriging-based methods, and (iii) neural network–based methods. In addition, the survey explores advanced techniques currently underutilized in aerodynamic database applications but that show promise. These methodologies are discussed in the context of addressing limitations inherent in traditional approaches, such as dependency on nested sampling plans and linear correlation assumptions between low- and high-fidelity datasets. The review indicates that, although multi-fidelity data fusion is well established in aerospace aerodynamic database generation, its direct translation to motorsport requires additional considerations. In the Formula One
Ongley, Thomas James HenryTeschner, Tom-RobinAshton, NeilSiampis, Efstathios
This SAE Standard establishes the test procedure, environment, and instrumentation for determining the sound levels of snowmobiles in the stationary test mode. This test method is intended to provide an accurate measurement of exhaust and other engine noise and may be used to evaluate new and in-use snowmobiles to determine compliance with noise control regulations. Sound level measurements obtained with this test method are not intended as an engineering determination of overall machine noise. For this purpose, the use of SAE J192 is recommended.
Snowmobile Technical Committee
This study aims to analyze the impact of spatial and aspatial factors on the safety driving behavior of motorcycle couriers in East Jakarta within the context of the gig economy. Both factors are integrated to clarify how spatial conditions and individual characteristics jointly shape couriers’ safety driving behavior. The Partial Least Squares Structural Equation Modeling (PLS-SEM) method was employed to examine the relationship between spatial and aspatial factors on safety driving behavior. Data were collected through questionnaires from 253 motorcycle couriers operating in three subdistricts in East Jakarta, namely Cakung, Pasar Rebo, and Pulo Gadung. The results show that safety driving behavior is significantly influenced by aspatial factors, particularly socioeconomic characteristics and personality traits. In contrast, spatial factors such as road conditions and daily activity patterns do not directly influence safety driving behavior, but exert indirect effects through the
Wahyuddin, YasserSitorus, Paldibo AlfriramsonPutri, KharuniaMaharani, Garnierita
This article investigates high-frequency noise in permanent magnet synchronous motors (PMSMs) for electric vehicles, originating from pulse width modulation (PWM). A theoretical model is developed to formulate the phase voltage under space vector PWM (SVPWM), explicitly accounting for the additional harmonic components generated by the discrete-time voltage update in digital control systems. This derived voltage waveform serves as the excitation source in an electromagnetic finite-element model, from which the PWM current harmonics and their resulting high-frequency electromagnetic forces are computed. Critical components of the electromagnetic force are then extracted through two-dimensional Fourier transform. A structural model of the motor, incorporating practical assembly constraints, is established and validated by experimental modal tests on a fully assembled motor unit. To enable rapid noise prediction over the wide speed range, vibro-acoustic transfer functions are introduced
Lin, FuChen, Yihui
The virtualization of powertrain systems is a key enabler for modern powertrain development. While physics-based 0D/1D simulation models provide accuracy and interpretability, these models are typically computationally demanding, prolonging the development process and usage throughout the V-cycle. Moreover, achieving real-time-capable simulation models through model simplifications remains challenging, as it often leads to significant losses in accuracy. In contrast, data-driven approaches can achieve high computational efficiency without significantly compromising model accuracy. This opens the possibility for not only online control applications, such as model predictive control or reinforcement learning, but also for computational expensive offline control prototyping using ultrafast-running data-driven digital twins. This work focuses on the elaboration of a scalable methodology for the development of ultrafast-running powertrain models for stationary and transient engine operation
Weller, LouisZanelli, AlessandroYang, QiruiBrutsche, MartinGrill, MichaelKulzer, André Casal
This SAE Aerospace Recommended Practice (ARP) recommends a methodology to be used for the design, analysis and test evaluation of modern helicopter gas turbine propulsion system stability and transient response characteristics. This methodology utilizes the computational power of modern digital computers to more thoroughly analyze, simulate and bench-test the helicopter engine/rotor system speed control loop over the flight envelope. This up-front work results in significantly less effort expended during flight test and delivers a more effective system into service. The methodology presented herein is recommended for modern digital electronic propulsion control systems and also for traditional analog and hydromechanical systems.
S-12 Powered Lift Propulsion Committee
Hybrid-electric (xHEV) and fuel cell electric vehicles (FCEVs) are expected to play a crucial role in the transition towards sustainable mobility in both the individual and commercial transportation sectors. As their market share increases, there is a need for advanced research to enhance overall vehicle efficiency – particularly through optimized energy management systems. For FCEVs, an optimal energy management strategy is essential to ensure safe and durable operation. For xHEVs, thermal management serves as a central lever for improving efficiency and controlling emissions, making it an integral part of the overall powertrain development process. Considering today’s regulatory landscape, these aspects must be addressed early in development. Consequently, a holistic methodological framework is required, enabling not only technical robustness but also economic benefits, such as reducing engineering effort through effective frontloading. This methodology is composed of integrated
Lavall, PhilippBeidl, ChristianFiore, LuisPapavasileiou, IoannisHohenberg, GünterKalski, Christian
Hybrid electric vehicles rely heavily on battery pack power capability, which is often compromised by non-uniform aging and thermal gradients. Conventional battery models typically use bulk state-of-health metrics, failing to capture localized degradation that leads to current imbalances and reduced pack utility. This paper presents a multi-scale modelling framework that integrates Electrochemical Impedance Spectroscopy data into a fractional-order equivalent circuit model to simulate localized degradation in Lithium Iron Phosphate cells. Results show that the terminal voltage of LFP cells can be accurately modelled using the proposed fractional-order equivalent circuit with a discrete transfer-function implementation, maintaining root-mean-square errors below 20 mV across most state-of-health and state-of-charge conditions. The validated cell model is then extended to a degradation-aware battery pack representation. The battery pack in this work utilizes a 200-kWh, 800 V architecture
Safavi, Seyed RezaHomayouni, HoomanShoa, TinaWang, JasonMcTaggart-Cowan, Gordon
Rigorous validation of SAE Levels 3 and 4 autonomous systems increasingly relies on simulation. However, the simulation-reality gap remains a challenge for human-in-the-loop assessments. This study empirically quantifies the behavioral fidelity of the Car-Learning-to-Act (CARLA) simulator by recreating specific real-world traffic scenarios using the high-precision exiD drone dataset. Twenty-five participants performed a series of maneuvers, including lane changes and time-critical cut-ins. Their performance was analyzed using Dynamic Time Warping (DTW), driver profiling, and Time-to-Collision (TTC) metrics. The findings reveal a clear distinction between relative and absolute behavioral validity. In strategic decision-making tasks, the simulation demonstrated remarkably high temporal fidelity. DTW analysis explained 94% of the trajectory variance. Participants initiated lane changes with an average lag of -9 frames (0.36 s) compared to naturalistic references. These results indicate
Rebling, PatrickAlphan, MetehanNenninger, Philipp
The transition toward climate-neutral transportation requires powertrain concepts that combine high efficiency with low pollutant emissions. In this context, hydrogen-fueled internal combustion engines represent a promising solution when hydrogen is produced from renewable energy sources. Owing to its specific molecular properties, hydrogen offers new possibilities for influencing and optimizing the combustion process and reducing the emission formation. This paper presents a numerical approach for characterizing the NOx formation in a single-cylinder research engine equipped with port fuel injection and a passive pre-chamber ignition system. The single-cylinder is operated over a wide range of engine loads and speeds, covering air-to-fuel ratios from λ=1.5 to 2.5 and achieving up to 23 bar indicated mean effective pressure. The study focuses on the influence of engine load and mixture composition on NOx emissions. A dedicated look-up table approach in combination with several reaction
Gal, ThomasVacca, AntoninoChiodi, MarcoSchmelcher, RobinKulzer, Andre Casal
Polymer electrolyte membrane (PEM) fuel cells represent one of the most promising solutions for decarbonizing powertrain technologies, as they can be employed as carbon-free electrical power source. However, performance degradation during their operating lifetime - caused among other factors by non-uniform reactant distribution and improper membrane humidification, which may lead to the formation of local hot spots - remains a significant challenge. Computational fluid dynamics (CFD) tools represent an effective approach for investigating the transport of oxygen and hydrogen within the cell and for optimizing the geometry of PEM fuel cell flow distributors. Thus, they can be exploited in order to improve the uniformity of current density and temperature distributions over the cell active area. In this work, a serpentine flow field PEM fuel cell is considered as test case. The distributor consists of a multi-pass serpentine flow-field composed of repeated sets of five parallel channels
Bulgarini, MargheritaDella Torre, AugustoMontenegro, GianlucaBaricci, AndreaMereu, RiccardoLalangui Gallegos, Jose A.De La Morena, Joaquin
With the continued expansion of electric mobility, liquid-cooled thermal management systems have become indispensable for ensuring the performance, durability, and safety of automotive battery packs. This work presents a novel cooling-plate design that integrates offset strip-fin turbulators to enhance convective heat transfer between lithium-ion cells and the circulating coolant. A comprehensive multi-region CFD model of the full battery pack is developed, incorporating an implicit lumped-parameter representation of cell heat generation. The numerical predictions are validated against dedicated experimental measurements available in the literature. Subsequently, a parametric study is conducted in which the number of hydraulic sub-modules and the inlet/outlet configurations are systematically varied to generate all feasible design permutations. The resulting configurations are compared to assess thermal performance and to quantify the benefits—as well as the potential penalties
Montenegro, GianlucaOnorati, AngeloDella Torre, AugustoTariq, Muhammad HasnainBonetti, Elisa
Biodiesel blends (B7, B20, B100) were evaluated in a Stage V-compliant SCR on Filter (SCRoF) system for heavy-duty applications to quantify soot reactivity and filter regeneration capability. Compared to conventional diesel (B7), B20 showed slightly faster regeneration performance under real-driving conditions, while B100 resulted in reduced particulate formation and higher soot reactivity, with more intense exothermic events requiring careful management. These differences are attributed to the distinct physical-chemical properties of the fuels (oxygen content, lower heating value) and their interaction with Diesel Oxidation Catalyst (DOC)/SCRoF. All tests were conducted on an engine dynamometer with a Cursor 9 FPT (Fiat Powertrain). Findings are discussed in the context of EU Stage V limits and practical control strategies for heavy-duty applications.
Costa, Simone
Electrical/Electronic Architectures (EEAs) are continuously evolving to meet newly emerging demands. In recent years, major drivers of this evolution have been the increasing software-defined nature of vehicles and the push toward automated driving. Key technologies such as edge-enhanced functions, vehicle-to-vehicle communication, and service-oriented architectures are therefore the focus of current research efforts. This paper presents a vision of how these technologies can be used to enable cooperation between vehicles, illustrated by using parked vehicles as edge nodes. These are typically seen as obstructions, as they significantly increase the risk of missing or misinterpreting vulnerable road users such as pedestrians or cyclists. Our proposed approach to counteract this problem is the use of the parked vehicles themselves as edge nodes that support object detection or even trajectory planning. Current research primarily considers smart traffic infrastructure, roadside units
Lüntzel, VitusLukezic, NikolaKraus, DavidSeidel, LucaBeck, MaximilianSchindewolf, MarcSax, Eric
This paper presents the development of a speed controller for e-bikes, designed as part of an energy-adaptive assistance system. The controller provides riders with appropriate support along planned routes, based on the available battery capacity. The control concept is intended for integration into existing commercial e-bikes without requiring extensive modifications to the drive system. Therefore, the rider remains part of the control loop, adjusting the support mode according to instructions from the controller. The speed controller is implemented as a rule-based state machine, enabling comprehensible design and parameterization. Since the rider must manually switch between support modes while riding, the control logic incorporates hysteresis and dead times to ensure stability, prevent oscillations, and avoid frequent mode switching. The user interface is a smartphone application that issues visual and audio instructions for switching support modes. An initial, system-independent
Rauch, YannickSimmann, GabrielSchneider, ManuelGoss, ChristianKriesten, Reiner
The detection of free space plays a fundamental role in ensuring the safe and efficient operation of heavy-duty vehicles, particularly in environments where the available area to maneuver is severely constrained, such as construction zones, rest areas, or loading docks. An accurate estimation of free space is essential to prevent collisions, maintaining operational continuity and minimizing vehicle downtime. As observed from the reviewed literature, despite the large number of proposed free-space detection methods, there is no concise and established definition about how free space should be determined, represented, and inferred, nor agreement on the semantic classes to be considered. This heterogeneity complicates systematic comparison and benchmarking across approaches. This paper presents a structured survey and methodological analysis of recent free-space detection and semantic segmentation approaches across automotive LiDAR-, camera-, and radar-based perception systems, as well as
Martinez, CristianPeters, Steven
The UMV Peoplemover 2+2 is part of a modular vehicle family (Urban Modular Vehicle) that includes derivatives for passenger and cargo transport in urban environments. The platform supports automated movers as well as conventionally controlled vehicles with a human driver, ensuring high flexibility across applications. The modular platform enables the extensive use of common parts, allowing the efficient and cost-effective realization of multiple vehicle variants. The increased share of common parts also improves sustainability by reducing derivative-specific parts, material usage, and production complexity. A drivable demonstrator of the UMV Peoplemover 2+2 has already been realized. The vehicle is designed for the automated transport of up to four occupants in a 2+2 vis-à-vis seating arrangement and is targeted at demand-oriented shuttle services. While the drivable demonstrator validated the proof of concept, it lacked the core Level 4 hardware and software stack for automated
Pohl, EricSchmid, FabianMünster, MarcoSiefkes, TjarkStuebler, TillmannMohammed, Shawan