Search Results

Recycling of advanced composites made from carbon fibers in epoxy resins is essential for two primary reasons. First, the energy necessary to produce carbon fibers is very high and therefore reusing these fibers could greatly reduce the lifecycle energy of components which use them. Second, if the material is allowed to break down in the environment, it will contribute to the growing presence of microplastics and other synthetic pollutants. Recyclability and Embodied Energy of Advanced Polymer Matrix Composites discusses current recycling and disposal methods—which typically do not aim for full circularity, but rather successive downcycling—and addresses the major challenge of aligning fibers into unidirectional tows of real value in high-performance composites. Click here to access the full SAE EDGETM Research Report portfolio.

Drop-in replacement biofuels and electrofuels can provide net-zero CO2 emissions with dramatic reductions in contrail formation. Biofuels must transition to second-generation cellulosic feedstocks while improving land and soil management. Electrofuels, or "e-fuels,” require aggressive cost reduction in hydrogen production, carbon capture, and fuel synthesis. Hydrogen has great potential for energy efficiency, cost reduction, and emissions reduction; however, its low density (even in liquid form) combined with it’s extremely low boiling temperature mean that bulky spherical tanks will consume considerable fuselage volume. Still, emerging direct-kerosene fuel cells may ultimately provide a superior zero-emission, energy-dense solution. Decarbonized Power Options for Civil Aviation discusses the current challenges with these power options and explores the economic incentives and levers vital to decarbonization.

Most heavy trucks should be fully electric, using a combination of batteries and catenary electrification, but heavy trucks requiring very long unsupported range will need chemical fuels. At the scale of heavy trucks, compressed hydrogen can match the specific energy of diesel, but its energy density is five times lower, limiting range to around 2,000 km. Scaling green hydrogen production and addressing leakage must be priorities. Hydrogen-derived electrofuels—or “e-fuels”—have the potential to scale, and while the economic comparison currently has unknowns, clean air considerations have gained new importance Decarbonized Power Options for Long-haul Commercial Vehicles discusses these energy sources as well as the caveats related to bioenergy usage, and reasons to prefer ethanol or methanol to diesel-type fuels. Click here to access the full SAE EDGETM Research Report portfolio.

Power options for off-road vehicles differ substantially from other commercial vehicles. Battery electrification is suitable for urban construction and light agriculture, but remote mining, forestry, and road building operations will require alternative fuels. Decarbonized Power Options for Non-road Mobile Machinery discusses these domains as well as the potential benefits and challenges of implementing fuels and energy sources such as bioenergy, e-fuels, and alcohol, as well as hydrogen, hydrocarbon, and direct methanol fuel cells. Click here to access the full SAE EDGETM Research Report portfolio.

To achieve decarbonization through means such as energy-efficient vehicles, active travel, and electrified road freight, solutions must reduce upstream demands on supply chains. However, even taking such a path, the energy transition will massively increase demand for raw materials such as cobalt, nickel, platinum group metals, and rare earth elements. Many of the metals can be largely substituted if required, so they are not truly critical to decarbonization. Critical Metals, Sourcing, and Long Supply Chains: Constraints on Transport Decarbonization discusses how lithium, silver, and copper are much more difficult to replace, and the energy transition is highly likely to depend on them. Greatly increased and more geographically dispersed investments in mineral extraction are vital. Governments must support this by giving investors clear signals about the rate of the transition, geological survey data, accelerated permits, and government backed finance.

Variable renewable energy (VRE), such as photovoltaic solar and wind turbines, will require new approaches to buffering energy within the grid. This must include significant ancillary services and longer duration storage to buffer seasonal variations in supply and demand. Such services may be economically provided by leveraging the battery resources of electric vehicles (EVs) for frequency response and energy storage for durations of up to a few hours, together with baseload and dispatchable power for longer duration buffering. Impact of Electric Vehicle Charging on Grid Energy Buffering discusses the unsettled issues and requirements needed to realize the potential of EV batteries for demand response and grid services, such as improved battery management, control strategies, and enhanced cybersecurity.

A narrow focus on electrification and elimination of tailpipe emissions is unlikely to achieve decarbonization objectives. Renewable power generation is unlikely to keep up with increased demand for electricity. A focus on tailpipe emissions ignores the significant particulate pollution that “zero emission” vehicles still cause. It is therefore vital that energy efficiency is improved. Active travel is the key to green economic growth, clean cities, and unlocking the energy saving potential of public transport. The Challenges of Vehicle Decarbonization reviews the urgent need to prioritize active travel infrastructure, create compelling mass-market cycling options, and switch to hybrid powertrains and catenary electrification for long-haul heavy trucks. The report also warns of the potential increase in miles travelled with the advent of personal automated vehicles as well as the pitfalls of fossil-fuel derived hydrogen power.

Electric road systems (ERS) enable dynamic charging—the most energy efficient and economical way to decarbonize road vehicles. ERS draw electrical power directly from the grid and enable vehicles with small batteries to operate without the need to stop for charging. The three main technologies (i.e., overhead catenary lines, road-bound conductive tracks, and inductive wireless systems in the road surface) are all technically proven; however, no highway system has been commercialized. Electric Road Systems for Dynamic Charging discusses the technical and economic advantages of dynamic charging and questions the current investment in battery-powered and hydrogen-fueled vehicles. Click here to access the full SAE EDGETM Research Report portfolio.

While platooning has the potential to reduce energy consumption of commercial vehicles while improving safety, both advantages are currently difficult to quantify due to insufficient data and the wide range of variables affecting models. Platooning will significantly reduce the use of energy when compared to trucks driven alone, or at a safe distance for a driver without any automated assistance. However, drivers typically drive closer to each other than recommended to achieve drafting efficiencies, which may shift the benefit of automated platooning to safety gains. More data will be needed to conclusively demonstrate these gains. Unsettled Issues in Commercial Vehicle Platooning discusses the technologies needed to enable close platooning, including brake system condition monitoring, vehicle-to-vehicle communication, and concrete infrastructure assessment. The report also looks at driver acceptance of platooning technology from a safety and job security perspective.

Sustainable first/last/only-mile (FLO-mile) transport is the key to sustainable travel. It could directly replace private car use for short urban journeys, which account for 1% of global greenhouse gas emissions. More importantly, it could enable public transport to be used for longer journeys, which account for 6% of emissions. Active travel, such as walking and cycling, has the lowest emissions and provides huge economic benefits that pay for the required infrastructure many times over. Unsettled Issues Regarding First- and Last-Mile Transport discusses the mass switch to more sustainable modes of transport and how to increase their perceived value to users. It also covers the prioritization of publicly owned cycles over rideshare options due to the latter’s higher lifecycle emissions, including manufacture, redistribution, and service operations and station construction. Click here to access the full SAE EDGETM Research Report portfolio.

While direct electrification appears to provide the most cost-effective route to decarbonization of commercial vehicles, uptake may be constrained by critical metal supply. Additionally, it will be many years before hydrogen power becomes decarbonized or if it can ever compete economically with direct electrification. An electric road system (ERS) could offer a highly efficient and cost-effective route to direct electrification that would greatly reduce the volume of batteries required, but pilot schemes are urgently needed to provide concrete data on operating costs for different ERS technologies. Furthermore, if plug-in hybrid electric vehicles could obtain most of their power from an ERS, liquid biofuels and “electrofuels” may prove useful for occasional off-grid range extension. To achieve extremely long-range for operation in remote locations, liquid fuels remain the only viable option.

With the current state of automotive electrification, predicting which electrification pathway is likely to be the most economical over a 10- to 30-year outlook is wrought with uncertainty. The development of a range of technologies should continue, including statically charged battery electric vehicles (BEVs), fuel cell electric vehicles (FCEVs), plug-in hybrid electric vehicles (PHEVs), and EVs designed for a combination of plug-in and electric road system (ERS) supply. The most significant uncertainties are for the costs related to hydrogen supply, electrical supply, and battery life. This greatly is dependent on electrolyzers, fuel-cell costs, life spans and efficiencies, distribution and storage, and the price of renewable electricity. Green hydrogen will also be required as an industrial feedstock for difficult-to-decarbonize areas such as aviation and steel production, and for seasonal energy buffering in the grid.

Currently, inaccuracies in machine tools are often not detected until after they have produced nonconforming parts, causing reworking or scrap. For high-value aerospace parts, a single rejected part is a significant cost. Low-value parts are often inspected less frequently, allowing many nonconforming parts to be produced before the issue is detected, also resulting in high cost. The alternative to relying on part inspection is to run frequent tests on the machine itself, but established calibration and health-check processes take between 20 minutes and several days. Emerging rapid and automated verification (RAV) processes enable machine tools to check their performance automatically in just a few minutes. These RAV processes can be performed frequently throughout the day, allowing machines to operate without human intervention for long periods of time. When an issue is detected, the machine may be able to recalibrate and then continue automatically.

Replacing fossil-fueled vehicles with battery-electric ones is a risky strategy. It is likely to be limited by the supply of metals critical to battery and solar cell production, and the investment required in decarbonized electricity. Using hydrogen to store renewable energy would greatly reduce efficiency, further increasing the investment required to decarbonize the electricity supply. The lowest technical risk and most economical pathway to decarbonization is reducing private car use. Shorter journeys would be made by walking and cycling – also known as “active travel” – with public transport used for most longer journeys. Realizing this cultural change in transport behavior will first require comprehensive networks for safe and enjoyable active travel, which separate walking and cycling. All locations should connect to either a fully segregated cycleway or traffic calmed roadways with a maximum speed of 30 kph.

Additive manufacturing (AM) is currently being used to produce many certified aerospace components. However, significant advantages of AM are not exploited due to unresolved issues associated with process control, feedstock materials, surface finish, inspection, and cost. Components subject to fatigue must undergo surface finish improvements to enable inspection. This adds cost and limits the use of topology optimization. Continued development of process models is also required to enable optimization and understand the potential for defects in thin-walled and slender sections. Costs are high for powder-fed processes due to material costs, machine costs, and low deposition rates. Costs for wire-fed processes are high due to the extensive postprocess machining required. In addition, these processes are limited to low-complexity features.

Cost reduction and increasing production rates are driving automation of aerospace manufacturing. Articulated serial robots may replace bespoke gantry automation or human operations. Improved accuracy is key to enabling operations such as machining, additive manufacturing (AM), composite fabrication, drilling, automated program development, and inspection. New accuracy standards are needed to enable process-relevant comparisons between robotic systems. Accuracy can be improved through calibration of kinematic and joint stiffness parameters, joint output encoders, adaptive control that compensates for thermal expansion, and feedforward control that compensates for hysteresis and external loads. The impact of datuming could also be significantly reduced through modeling and optimization. Highly dynamic end effectors compensate high-frequency disturbances using inertial sensors and reaction masses.

Within manufacturing, measurements are used to make decisions related to product verification and process control. The selection of production machines and instruments involves a trade-off to achieve the required accuracy while minimizing cost. Similarly, deciding on the level of confidence at which products are rejected is a trade-off between the cost of rejecting acceptable parts and the cost of passing substandard products to the customer. These trade-offs can only be optimized if the uncertainties are fully understood. Currently multiple methodologies are used to understand uncertainties and variation within manufacturing, such as measurement systems analysis (MSA), statistical process control (SPC), and uncertainty evaluation. The industry lacks a unified approach that provides a complete understanding of uncertainty. This means that optimal decisions cannot be made to maximize the profitability of production systems.