AUTONEWS

Why you need to charge your electric car more often in the cold: Tips from a battery expert

When the temperature drops to -20°C, electric car owners quickly notice it in their wallets. But is it just a matter of driving with the heat on full blast? And what can we do to save the battery as much as possible?

You charged your car to 80% last night, and this morning it's at 78%. The fast charger, which usually takes half an hour, now takes almost two hours. And on the way to work, you notice that the battery percentage is dropping faster than normal.

Senior researcher and battery expert, Fride Vullum-Bruer, explains why batteries behave the way they do, and what users can do to protect the battery as much as possible in the cold.

What happens to the battery in cold weather? When the temperature drops, the chemical processes in the battery slow down, and the internal resistance increases. This means that the battery becomes less efficient at delivering energy. But what actually happens inside the battery and why are lithium-ion batteries particularly vulnerable to cold?

"A battery can be seen as a system where lithium ions must move freely back and forth between two sides—the anode and the cathode—to produce electricity. The ions float in a solution in which electrolytes dissolve and enable the ions to conduct electricity. When it gets cold outside, this substance becomes viscous and sluggish, almost like honey. In the worst case, it can solidify completely. The lithium ions then have trouble moving and cannot generate electricity as easily," Vullum-Bruer says.

She also adds that the battery can "give up" earlier when it is very cold:

"The battery voltage drops faster in the cold, and when it reaches a certain level, called 'cut-off,' the battery will stop altogether, even though there is still energy left. This is a protective mechanism to prevent damage to the battery."

Here are the researcher's six tips for winter battery care:

Preheat the car while it is charging, not afterwards.

Do not charge the battery while the car is cold; instead, charge it immediately after you have been out and about so that the battery is warm.

Avoid charging to 100% on a daily/weekly basis; stop at 80–90%.

Use the steering wheel and seat heating instead of the passenger compartment heating, as these draw less electricity.

Avoid making a lot of short trips when it is very cold outside.

Feel free to add an additional quick charging stop if you have doubts about whether the battery will last for the entire journey.

It's not just about the heater...Many people may think that the range loss in winter is mainly due to driving with the heater on. This is not entirely true. Although heating the passenger compartment uses energy, the most important reason for reduced range is that the battery gets cold and processes run slower.

But how much energy is actually used for preheating and keeping the car warm while driving?

Vullum-Bruer explains, "The amount of energy used to heat the car, and the amount that is lost while driving, depends on several factors, including the size of the car, battery chemistry and, not least, how cold it is outside. The colder it is, the greater the energy loss. For a newer electric car the size of a Tesla Model 3 or Y, it typically takes about 0.5–1.5 kWh for preheating. In addition, 1–2 kWh per hour is often used to maintain the heat while driving."

The figures show that heating the car accounts for a relatively small part of the total energy consumption, especially compared to the effect that the cold has on the battery itself.

"For a battery of around 75 kWh, this corresponds to an energy loss of approximately 2–5%. The energy consumption of steering wheel heating and seat heating is another order of magnitude smaller than this. By comparison, the battery itself can lose 20–50% of its normal range when the outside temperature hovers around -20°C," she adds.

Avoid charging an ice-cold battery...When is the best time to charge? Should you charge the car overnight or is it okay to fast charge on your way to work the next day?

In general, charging is faster when the battery has reached its operating temperature. Therefore, charging when you get home from a trip instead of waiting until the next morning can be a good idea. Fast charging an ice-cold battery can take a long time, because the battery has to first warm itself up.

Vullum-Bruer explains that low temperatures affect all the processes in the battery, including the charging process itself.

"As already mentioned, all the processes in the battery are slower when it is cold. This also applies to charging. The Li-ions are transported much more slowly at low temperatures, which is why it is a good idea to charge when the battery is already warm."

She also emphasizes that charging in the cold, and especially fast charging, can in some cases be harmful to the battery.

"What can happen is that the Li-ions settle on the surface of the anode as metallic lithium, instead of going into the material and being stored between the graphite layers. This is called plating and leads to a loss of active lithium."

Over time, this can have more serious consequences.

"Needle-like lithium filaments called dendrites may also form, which can lead to a short circuit in the battery. In the worst case, this can start a fire in the battery."

Preventing energy loss is key...At the same time, Vullum-Bruer points to several measures that can help reduce the load on the battery, especially now in the winter months. "Preheating the car and battery will reduce energy loss when it is cold outside. Research also shows that the battery will have a much longer lifespan if you do not constantly charge to 100%."

She explains that the longest lifespan is achieved when the battery is operated within a relatively narrow range, which can be challenging to maintain in practice.

"The longest lifespan is achieved if the battery is operated between 40 and 60%. This is generally not very practical in everyday life. However, if you manage to keep the battery between 20 and 80%, the lifespan of the battery will increase considerably compared to constantly charging to 100%.

"This recommendation applies regardless of the temperature outside, but becomes extra important in the cold.

"In that case, you should be particularly careful that the battery does not remain fully charged for a long time. If the car is not used for an extended period, the battery should only be charged to between 40 and 60%."

This contrasts with gasoline and diesel cars, where a full tank is often recommended to reduce condensation.

Better batteries in sight?...What is the status of research when it comes to electric car batteries? Will there be batteries that can withstand cold better, and when can we expect this to happen?

Vullum-Bruer points out that a lot of research into new solutions is happening, but the path from lab to road can be a long one.

"A lot of research into different battery technologies is underway, and not all of them are equally mature or relevant for electric cars. The most promising technology for better EV batteries now appears to be solid-state batteries (or semi-solid) where the liquid electrolyte is replaced with a solid (or semi-solid) electrolyte.

"This technology has been talked about for a long time without it having made it to the market. However, several Chinese players have now announced that they expect scaled-up production within the next one to three years."

The Chinese car manufacturer FAW has recently unveiled its first prototype car with a solid-state battery. Developments indicate progress, but it will still take time before such batteries become part of everyday life for ordinary electric drivers.

Whether and when new battery technology will have an impact on the electric vehicle models currently on the market will depend on further testing, production and commercial maturation. For now, current battery technology sets the framework for how EVs should be used, especially in the winter months, according to the researcher.

Provided by SINTEF

AUTONEWS

Cheaper EV batteries? How a fabrication tweak makes sulfur work in solid-state cells

Spurred by EVs and electrified aviation, global demand for lithium-ion batteries is expected to more than double its 2023 levels by 2030, far outstripping demand, according to S&P Global Insights. New batteries must be powerful, but also affordable enough for industry to adopt on a massive scale. As a battery component, sulfur—low-cost, abundant and with a high theoretical specific capacity—seems tailor-made for the challenge. But so far, that theoretical capacity has stayed theoretical.

Chen-Jui (Ben) Huang is a co-author of a recent paper published in Nature Communications that is cracking the code on sulfur, developing practical, powerful all-solid-state batteries using lithium-sulfur conversion chemistry. Huang is a postdoctoral researcher for the University of Chicago Pritzker School of Molecular Engineering (UChicago PME) and University of California San Diego Nanoengineering department's Laboratory for Energy Storage and Conversion (LESC).

"Pricewise, sulfur is the ultimate inexpensive material that you want to put in the battery," said Huang. "A key limitation of sulfur cathodes is that sulfur is intrinsically insulating, with negligible electronic conductivity and limited ionic transport. As a result, establishing continuous electron/ion percolation is challenging, and a significant fraction of sulfur can remain electrochemically inaccessible, making it difficult to realize the full theoretical capacity."

By finding the perfect particle size for solid-state electrolyte powder and changing the fabrication strategy, the team created a sulfur-based composite cathode that delivers a discharge specific capacity of about 1,500 milliampere-hours (mAh) per gram of sulfur. This puts science closer than ever to tapping sulfur's theoretical capacity of 1,675 mAh per gram. Furthermore, the team successfully demonstrated this performance in a practical pouch cell format, proving the technology's scalability and potential for real-world EV applications.

The work is the result of an ongoing industry–academia partnership with South Korean battery-maker LG Energy Solution through LG Energy Solution's Frontier Research Lab (FRL) program.

"Instead of adding new materials or coatings, this work shows that simply arranging the existing materials more carefully allows sulfur to react much more efficiently," said Seung Bo Yang, a Senior Researcher at LG Energy Solution and Visiting Industrial Fellow at LESC. "By optimizing particle size and how the materials are mixed, the battery can deliver high capacity, practical energy output in an all-solid-state design."

This new research builds on the partnership's prior lithium-sulfur work, part of their ongoing effort to combine solid-state batteries' safety and stability with sulfur's high capacity and low cost.

"High-performing batteries help no one sitting in labs. To hit our energy and climate goals, we need them out working in the real world. That means they must be affordable at scale," said UChicago PME Prof. Shirley Meng, the first corresponding author of the new work. "This partnership between UChicago PME, UC San Diego and LG Energy Solution continues to show that low cost and high performance are not mutually exclusive. In fact, it's the route we must pursue to create lasting real-world impact."

Chen-Jui (Ben) Huang, a postdoctoral researcher at the UChicago Pritzker School of Molecular Engineering and UC San Diego's Laboratory for Energy Storage and Conversion, is a co-author of a new paper that's developing practical, powerful all-solid-state batteries using lithium-sulfur conversion chemistry. Credit: UChicago Pritzker School of Molecular Engineering / Jason Smith

One-step milling...One of the biggest reasons EV makers are exploring all-solid-state batteries is safety. If they crack from age or a car crash, batteries with liquid components can get involved in thermal incidents.

"The intrinsic property of solid-state batteries is that we replace those flammable organic liquid electrolytes with non-flammable solid-state electrolytes," Huang said. "Everything is dry, not a single drop of liquid."

This means all three materials that go into a sulfur-based positive electrode—the sulfur active material, the solid-state electrolyte (SSE), and the conductive carbon—must be powders. Combining them is commonly done either by hand-mixing or through a multi-step milling process where the three are milled to powder separately, then combined.

Hand-mixing performed poorly and multi-step milling suffered from low utilization, implying the sulfur and SSE particles weren't in close enough contact.

The team developed a one-step milling process where all three materials were ground to powder together. In addition to creating a uniform blend, it creates a metastable interphase that partially reacts the sulfide electrolyte with the sulfur cathode material, actually improving performance.

"By enabling higher energy density, this research points toward batteries that could allow electric vehicles to travel significantly longer distances," Yang said.

One major finding was that the SSE particles must be on the micron level for peak performance.

"The particle size of the solid electrolyte matters, because you are combining solid particles with solid particles. So how they stack with each other, or how they can be packed the closest in the cell stack, that matters," Huang said.

The team demonstrated a marked performance improvement in a practical pouch-cell format (left). In contrast to the pellet-cell configuration (right), which typically requires a bulky compression fixture and has its active area constrained by the pellet geometry, pouch cells use sheet electrodes that can be readily scaled to larger areas—highlighting strong potential for EV-relevant designs. Credit: UChicago Pritzker School of Molecular Engineering / Jason Smith

Other benefits...The paper also sets a plan to offset "breathing," a phenomenon where materials expand and contract as they charge and discharge, adding stress and wear as the batteries cycle.

Sulfur-based electrodes "breathe" in the opposite way from the more common nickel–manganese–cobalt (NMC) electrodes: When sulfur tends to swell, NMC tends to shrink, and the reverse is also true. The researchers took advantage of this by pairing a silicon negative electrode with a lithium sulfide positive electrode. As the battery cycles, one side expands while the other contracts, so their volume changes partially offset each other and reduce the net change in stack thickness.

This complementary behavior helps the cell remain mechanically steadier and limits stress buildup. In practice, the team pairs Si with Li2S, and lithiated Si (LixSi) with sulfur, so this out-of-phase volume-change mechanism is maintained across the relevant reaction states.

"Collaboration between industry and academia is essential to keep pace with the rapidly evolving battery market," Yang said. "As demand for electric vehicles and energy storage grows, combining industry's manufacturing expertise with innovative university research helps accelerate the development of next-generation battery technologies."

Provided by University of Chicago

 

AUTONEWS

These are the new EVs we're most excited about in 2026

After years of experimentation and early adoption, automakers are rolling out the next generation of electric vehicles that better align with people's needs and expectations. This year, you can expect to see new EVs that have more range, easier charging, lower pricing and distinctive designs. The experts at Edmunds have identified the five most compelling electric vehicles that will debut in 2026.

BMW iX3...Most luxury electric SUVs to date have been either expensive, high-end offerings or entry-level models with limited appeal. The 2027 BMW iX3 has us excited because it hits the sweet spot of price and space that so many people like about the regular X3. The iX3 is designed from the ground up as an electric vehicle and prioritizes efficiency, interior space, and charging performance in ways earlier EVs could not.

BMW says the iX3 will offer about 400 miles of range, which is considerably longer than what many other current electric SUVs are capable of. That range is complemented by quick charging capability and compatibility with Tesla's Supercharger network for easy long-distance driving. The new iX3 will also boast sporty performance, a classy cabin design and BMW's latest infotainment technology...Estimated release: summer 2026. Estimated starting price: $60,000

Chevy Bolt...The return of the Chevrolet Bolt is significant because it reinforces the idea that EVs don't need to be expensive to be relevant. Chevy positions the new Bolt as a more refined, modern version of the original, produced from 2017 to 2023. The 2027 Bolt is more of an update than a completely new design. It primarily has refreshed styling and quicker charging capability.

Range is expected to be 262 miles on a full charge, and the addition of a Tesla-style charging port gives the Bolt easy access to Tesla's nationwide charging network. That's a major upgrade for a vehicle aimed at affordability and daily usability. The new Bolt offers one of the clearest on-ramps into EV ownership: manageable price expectations, realistic range for commuting, and fewer charging headaches...Estimated release: spring 2026...Starting price: $28,995, including destination

Rivian R2...The Rivian R2 is a hotly anticipated EV because it makes Rivian's adventurous brand design accessible to a wider range of buyers. Rivian, a relatively new automaker that also builds the three-row R1S SUV and R1T, designed the R2 to compete directly with popular small electric SUVs such as the Hyundai Ioniq 5 and Tesla Model Y.

The R2 seats five and has a promised range of more than 300 miles to complement Rivian's focus on off-road capability and performance. It will come with a single electric motor for rear-wheel drive and offer all-wheel drive coming from two or three motors. If Rivian delivers on its promises, the R2 could become one of the most versatile EVs on the market for families, outdoor enthusiasts and urban drivers alike...Estimated release: spring 2026. Estimated starting price: $45,000

Slate Truck...Slate is a brand-new American automaker, and its first vehicle is unlike any other EV currently on sale. It starts out as a no-frills two-passenger electric pickup truck that's shorter than even a Ford Maverick compact pickup. There's no standard audio system, no center touchscreen screen, or even power windows to start. Every Slate Truck comes off the assembly line exactly the same.

However, Slate will let you extensively customize the vehicle after the fact. It will offer a kit to turn the truck into a five-passenger SUV, for example. There will also be different exterior wrap colors and various wheel-and-tire combinations to choose from. The Truck's standard battery is said to provide up to 150 miles of range on a single charge; an optional larger battery extends that to 240 miles...Estimated release: late 2026. Estimated starting price: $28,000

2026 Subaru Trailseeker...The 2026 Subaru Trailseeker will be the brand's second EV after the Solterra crossover SUV. It's longer than the Solterra, offering additional cargo and rear-seat passenger space. It's not too much of a stretch to say the Trailseeker is what the Outback would be if it were to become an EV. It has standard all-wheel drive and a slightly lifted stance to help it perform better on dirt roads and mild off-road trails.

Subaru says the Trailseeker can drive up to 260 miles on a single charge. That's not great for an EV in 2026, but it does offer standard all-wheel drive and quick acceleration. The Trailseeker shares many of its underpinnings with the similarly new Toyota bZ Woodland, so either EV could appeal to you if you like the idea of owning an electric SUV with an outdoorsy vibe...Estimated release: spring 2026. Starting price: $39,995, including destination

Edmunds says...These five vehicles illustrate a move in the right direction for EVs and why 2026 matters for shoppers. From luxury and affordability to utility and adventure, each addresses a different buyer need without asking for major compromises.

© 2026 The Associated Press. All rights reserved.

AUTONEWS

Improved EV battery gains will outmatch degradation from climate change, research shows

Climate change was poised to create an interesting catch-22 for electric vehicles. Electrifying transportation can go a long way to reducing carbon emissions that are driving up global temperatures. But warmer temperatures also accelerate the degradation of batteries, whose performance can be a make-or-break factor for people considering an EV purchase.

In a new study led by the University of Michigan, however, researchers have shown that batteries have gotten a lot better over the past several years. So much so, in fact, that their gains will more than offset their expected heat-related degradation on a warming planet.

"Thanks to technological improvements, consumers should have more confidence in their EV batteries, even in a warmer future," said Haochi Wu, lead author of the study published in the journal Nature Climate Change. Wu performed the work as a visiting doctoral student at the U-M School for Environment and Sustainability, or SEAS.

The team's study combined EV simulations with models of battery degradation and climate change to compare the endurance of old batteries made between 2010 and 2018 with new batteries made between 2019 and 2023. In a scenario where Earth warms by 2 degrees Celsius, old batteries would see their lifetimes drop by an average of 8% up to a maximum of 30%. For new batteries, the average lifetime drop is just 3% and the maximum is only 10%.

"I think these improvements are well-known to experts in the field. But, when I started this project, I was looking at web forums and reading how people were deciding on cars," Wu said. "There are still a lot of durability concerns about EV batteries."

Those concerns were driven, in part, by a rash of incidents about a decade ago where EV drivers in warmer climates saw their battery capacities evaporate, Wu said. But those should be problems of the past, according to the team's analysis.

Hot takes...The researchers looked at battery lifetimes across 300 cities around the world in a variety of warming scenarios and found that the improvements held up globally. In fact, the warmest cities, like those nearest the equator, actually stand to see the biggest gains.

The team's methodology also stood out to experts in the field, as well as to editors at the journal that published the work. Their framework coupled climate projections with experimentally calibrated models of battery degradation and simulations of EV driving behavior to create high-fidelity battery profiles at granular temporal scales, Wu said.

"The authors find an interesting way to model the important role of technological advance in mitigating the negative effect of climate change," wrote the editorial team at Nature Climate Change. The journal also invited Wu and Craig to submit a research briefing about their work, making it more visible and accessible to the research community.

There are some important caveats associated with the study's results, however, pointed out senior author, Michael Craig, associate professor at SEAS and the Department of Industrial and Operations Engineering, or IOE. Importantly, the team used two representative EVs for their work, the Tesla Model 3 and the Volkswagen ID.3.

"In regions like Europe and the United States, we feel like we've got a good handle on the battery technology that's available in those regions," Craig said. "But when we're looking at cities in India or sub-Saharan Africa, for example, they may have very different vehicle fleets—and they almost certainly do. So our results may be optimistic for those regions."

In these regions, the impacts of warming are also going to be worse and felt more acutely, which highlights another dimension of how inequalities are exacerbated by climate change. This theme also came through in another recent study by Craig and Wu.

On a planet that warms by an average of 2 degrees Celsius, electric vehicles with batteries made between 2010 and 2018, would see their lifetimes decline by up to 30%, according to new research from the University of Michigan. But, thanks to improved technology, newer batteries made between 2019 and 2023, that degradation maxes out at just 10%. Credit: H. Wu et al. Nat. Clim.

Road maps to resilience...Published in the journal Joule, the researchers' related project was inspired by a similar question about how global warming would impact rooftop solar cell performance. In particular, they examined where climate change would push solar panels into high-temperature risks and extreme high-temperature risks, which are technical thresholds defined by the International Electrochemical Commission, or IEC.

These high-temperature risks can accelerate the degradation of conventional solar panels, which can reduce their reliability and prompt sooner-than-expected replacement.

They found that, under the current IEC standards, those risks are underestimated for more than half of our existing and future rooftop photovoltaic installation capacity. Again, these risks will be most acute where warming will be the greatest, which are often low- and middle-income areas.

"On the solar side, we're saying we know the risk is coming, so we need to prepare for it and update our standards. But if you update the standards, there's a whole menu of options available to panel developers, manufacturers and installers that can deal with that risk," Craig said. "Just like EV technology is mitigating that risk, we can mitigate the risk in solar. We just need to have some foresight."

Although that by itself doesn't solve the issues of inequity, it does mean that groups looking for answers can focus on how the technology is deployed rather than whether it exists.

"More vulnerable regions are going to suffer a larger negative impact from climate change, but we're finding technological improvements can mitigate that," Wu said. "That is good news."

Parth Vaishnav and Jiahui Chen of U-M also contributed to the Nature Climate Change study. Qinqin Kong and Matthew Huber of Purdue University were co-authors of the Joule report. Mingyan Sun of Peking University was a collaborator on both projects.

Provided by University of Michigan 

 

TUNNING

G-Power BMW M2 700

The pictures show the G-Power G2M Bi-Turbo, a modified BMW M2 with up to 700 HP.

The M2 is powered by a 3.0-liter six-cylinder twin-turbo engine with 480 HP and 600 Nm as standard, while the M2 CS has 530 HP and 650 Nm.

G-Power has several packages for the M2, so their base package includes a boost to 600 HP and 720 Nm. Then comes the mid-level upgrade with 650 HP and 780 Nm.

BMW isn’t committing to an M2 CSL for now, but it’s not completely shutting the door either. While a factory-built hardcore version remains a definite maybe, the tuning scene is relentless in its pursuit of wild G87 builds. The latest comes from G-Power, and it makes the M2 CS look tame by comparison.

The Competition Sport didn’t get a carbon-fiber hood, even though the old F87 had one. BMW told us last year it focused more on the rear end with its ducktail spoiler, while the front was largely carried over. Before a possible M2 CSL addresses the lack of a lightweight hood, G-Power has stepped in with one priced at €5,950. It’s made entirely from carbon fiber and incorporates a pair of air intakes to help cool the engine.

The S58 remains under the hood, but the tuner has pushed the twin-turbo, 3.0-liter inline-six to 700 horsepower. For the sake of accuracy, that’s 700 PS (Pferdestärke). It translates to 690 hp, though a 10-hp difference at this level is unlikely to be noticeable. Torque climbs to a mountain-moving 850 Nm (627 lb-ft), sent exclusively to the rear wheels.

We imagine G-Power’s M2 must be a riot to drive, considering it’s still a relatively small car. Well, at least by 2026 standards. Sending that much power to just two wheels should make it both hugely playful and demanding. It’s certainly not for the faint-hearted, but experienced drivers are likely to relish it. A €3,595 software upgrade unlocks this output, though it requires an ECU unlock that costs an additional €595.

Perhaps the long-rumored M2 xDrive would better suit G-Power’s upgraded engine, although BMW remains tight-lipped. The all-wheel-drive G87 is reportedly due this year with “only” 475 PS (469 hp), but nothing is official yet. What we do know is that a Track Package will debut this year as a new optional kit and as a retrofit for existing cars.

Looking ahead, the M2 appears set for the long haul. We’ve heard the San Luis Potosí plant in Mexico will continue production until mid-2029. That gives BMW plenty of time to spice up its baby M car while, ideally, keeping the manual gearbox alive. This generation of the M2 could go down in history as the last-ever BMW with three pedals, though BMW will likely phase out the M4 around the same time.

The top version of G-Power's offer for the M2 offers as much as 700 HP and 840 Nm.

G-Power has also removed the maximum fuel consumption lock, so this M2 can reach more than 300 km/h.

The package also includes 20- and 21-inch Hurricane RR wheels, 285/30R20 and 295/25R21 tires, a GP-Venturi carbon fiber hood (priced at 5,950 euros), a sports exhaust system, modified suspension, and a customized interior (leather, carbon fiber, new floor mats, etc.).

Autonews

AUTONEWS

Extra 'set of eyes' for self-driving cars: Roadside radar sensors could reduce blind spots

Autonomous vehicles (AVs) are becoming increasingly common on roadways, but making them as safe as possible may entail going beyond the particular specs of the vehicles themselves to upgrading the roadway infrastructure. EyeDAR, a low-power millimeter-wave radar sensor roughly the size of an orange, could provide radar-equipped AVs with critical inputs about surrounding traffic, extending and enhancing the vehicles' sensing accuracy.

Placed at key points such as streetlights and intersections, these low-profile, inexpensive sensors could ensure that AVs never fail to pick up on emerging obstacles, even when they are not within proper range of the vehicles' onboard sensors or when visibility is severely limited.

Kun Woo Cho, a postdoctoral researcher at Rice University who leads the EyeDAR research project, introduced the technology at HotMobile, The International Workshop on Mobile Computing Systems and Applications, which took place in Atlanta Feb. 25–26. The research is published in Proceedings of the 27th International Workshop on Mobile Computing Systems and Applications.

"Current automotive sensor systems like cameras and lidar struggle with poor visibility such as you would encounter due to rain or fog or in low-lighting conditions," said Cho, who works in the lab of Ashutosh Sabharwal, Rice's Ernest Dell Butcher Professor of Engineering and professor of electrical and computer engineering. "Radar, on the other hand, operates reliably in all weather and lighting conditions and can even see through obstacles."

Radar systems transmit signals in a given direction, and when that signal encounters an obstacle in its path, part of it reflects back to the source, carrying information about the obstacle. However, only a small fraction of the radar signal emitted is reflected back, and most of it actually bounces away from the source device.

In the context of self-driving vehicles, this means that a large fraction of the radar signal their sensing stack emits scatters away from the vehicle, leaving them with an incomplete view of their surroundings. Pedestrians emerging from behind large vehicles, cars creeping forward at intersections or cyclists approaching at odd angles can easily go unnoticed.

Thanks to its placement on roadside infrastructure such as traffic lights, stop signs or streetlights, EyeDAR can capture radar reflections that would otherwise be lost. The device's unique structure allows it to determine the direction of reflected signals and report that information back to self-driving vehicles.

                         Researchers and EyeDAR prototype. Credit: Jared Jones / Rice University

"It is like adding another set of eyes for automotive radar systems," said Cho, who specializes in metamaterial antenna design.

EyeDAR boasts a simple, elegant design inspired by a highly efficient real-world sensor—the human eye. The device consists of two main components: a 3D-printed Luneberg lens made from resin which functions similarly to the lens of the eye, focusing incoming signals from any direction onto a focal point on the opposite surface; and an antenna array surrounding the lens on the back end that functions like a retina, detecting the signal and determining its direction.

Whereas conventional radar systems rely on large antenna arrays and complex algorithms to estimate angles, EyeDAR's physical design does most of the computation work typically required for direction finding—one of the most power- and data-intensive tasks in radar processing.

"Our lens consists of over 8,000 uniquely shaped, extremely small elements with a varying refractive index," Cho said.

Through an intentional distribution of these elements, the lens structure interacts with incoming radar signals in a smart way, routing them to the right spot on the antenna array. The approach has proved fruitful: In testing, EyeDAR was able to resolve target directions more than 200 times faster than traditional radar designs.

Moreover, EyeDAR communicates what it sees without transmitting new signals. Instead, the sensor alternates between absorbing incoming radar waves and reflecting them back to the source radar in a form it can interpret as a sequence of 0s and 1s.

"Like blinking Morse code," Cho said. "EyeDAR is a talking sensor—it is a first instance of integrating radar sensing and communication functionality in a single design."

This combination of sensing and communication in a compact, inexpensive and low-power architecture makes it feasible to deploy large numbers of sensors across roadways. In the case of self-driving cars, the system promises to be especially useful in dense, high-traffic urban settings. However, the potential application space is much wider: EyeDAR could be integrated into robots, drones and wearable platforms. Networks of these sensors could also share information with one another, allowing each device to see well beyond its own range of sight.

Cho said she is particularly interested in what the system represents from a computing standpoint. As autonomous systems increasingly interact directly with people, Cho argues that intelligent physical design will have to complement artificial intelligence.

"EyeDAR is an example of what I like to call 'analog computing,'" Cho said. "Over the past two decades, people have been focusing on the digital and software side of computation, and the analog hardware side has been lagging behind. I want to explore this overlooked analog design space."

Provided by Rice University 

BMW

YouTuber installs iconic engine in BMW i8

The BMW i8 has always looked like a supercar with its futuristic design, but its performance has never quite matched that aesthetic. In its latest iteration, the 1.5-liter plug-in hybrid developed a total of 360 horsepower.

YouTuber Trevor Elam has corrected what many consider BMW’s biggest mistake, replacing the hybrid drivetrain with the legendary B58 3.0-liter inline-six.

It remains to be seen how Trevor will fit an engine twice as long as the original in the i8 — especially since he’s not putting it behind the cabin but up front where the front electric motor once lived — but if he gets it to work, it will be a rowdy drive, with the inline-six coming from a crashed 2017 M340i xDrive that was capable of around 700 wheel horsepower. For the record, the original powertrain was only rated for a combined total of 369 hp, so Trevor will need to use the transmission and possibly even the drive shafts and hubs of his donor car to put that power down. He’s already conceded that custom subframes will be necessary, with these designed to allow the transmission and transfer case of the swapped power unit to fit where the high-voltage battery did.

There’s also the issue of tuning, and we presume the 3 Series will have to donate its ECU to the build. Additional effort may also be required in the bodywork department, since the i8’s famously skinny original wheels may need upgrading, and that could cause clearance issues with the carbon fiber monocoque. At this point, it seems simpler to body-swap the i8 onto a 2 Series, but perhaps Trevor thinks that’s too easy.

The project is still in its early stages, and Elam’s first video shows him removing the original powertrain from the i8. The process involves removing the battery to make room for the transmission tunnel and designing an entirely new subframe to accommodate the new engine and transmission.

The inline-six will be mounted up front, where the electric motor used to be. The engine comes from the 2017 BMW 340i xDrive and in production developed 326 horsepower and 450 Nm. However, the plan is to upgrade it to deliver as much as 700 horsepower.

It is not yet known how the installation of a significantly different engine will affect the weight distribution and handling of the car, but it seems that the original hybrid architecture offers enough space for the necessary mechanical changes. Many hope that the project will not encounter insurmountable obstacles, because an i8 with a real inline six-cylinder engine would be the dream come true for many enthusiasts.

When the BMW i8 was introduced more than a decade ago, many considered it a real car with the wrong powertrain. The manufacturer, along with the i3, tried to create excitement around hybrid technology with a futuristic design and advanced materials. Yet all fans have wanted from the elegant coupé was a true BMW high-performance engine – and it seems that this could finally be achieved, albeit in a unique version.

Autonews