C8 Gets Needed 48V: A Technical Deep Dive

[John]

Five days ago I awakened, like many, to reports that the ME was getting an alleged electrical makeover, and while I initially doubted it, I am now not doubting the reports that the mid engine C8 is getting an electrical makeover.

This thread however, will not engage in the contentious debate of whether the C8 is or is not delayed, Timeliness of the alleged delays to the appearance of the C8 will solely go into the existing thread, where all can continue to discuss whether as the problem was first identified over six months ago, has already been solved, or whether it resulted in a delay of between even one minute, or at the other extreme, a model year as recently mentioned:

https://www.midenginecorvetteforum.c...ectrical-issue

So two separate issues please, being discussed in two threads.

THIS THREAD IS INSTEAD FOR THOSE WHO WISH TO FURTHER DELVE IN THE SCIENCE, INFO AND THE DETAILS OF WHY THE INDUSTRY, NOT JUST THE C8 CORVETTE, IS MOVING INTO THE WORLD OF A 48V ELECTRICAL SYSTEM,

What changed my mind in the last five days? Primarily the posts in the preceding, linked thread made by Bikerjulio. Thank you BikerJulio!!! I thank him for greatly adding to my knowledge of this literal jump shift now going on in the industry, for as he correctly noted in that linked thread, there are now more than 10 major OEM’s making that shift.

[John]

2) I started making my mind makeover based on a collection of posts Julio earlier made including these (again in the preceding linked thread):

If the car has an auto stop-start system, then more components than normal will be electrically powered - A/C, cooling pumps, fans etc.


Although a lot of the talk around 48V systems is on fuel economy, there is also a significant advantage for high performance cars in that taking accessories off the engine frees up more power for acceleration. Plus if it's a mild hybrid there's an immediate battery boost to acceleration as well.

Maybe that's why the brakes appeared smaller than expected on the mules - regenerative braking from the motor/generator/starter flywheel.

As cars shift to more electrically driven accessories though - power steering, water pump, fans, A/C, starter, etc, then it makes a lot of sense to switch to a 48V system or a dual 12/48V system. The increased voltage allows much smaller motors and cabling for weight reduction, and maybe cost reduction as well.
So possibly GM has decided to pioneer a higher voltage system in their halo car. Not that this would be the cause of a problem, if there is one. Just my speculation.

“As auto manufacturers continue to replace mechanical systems with electrical components, particularly in stop-start vehicles (vehicles that shut off their engines at red lights and other stopping situations), the demands for power have begun to outstrip the capabilities of traditional battery systems.

Increasing the voltage of certain subsystems by four times – going from a nominal 12V to a 48V system – means that the same power can be delivered with one-quarter of the current. According to a new research brief from Navigant Research, sales of light-duty vehicles with 48V electrical subsystems will reach nearly 13.5 million by 2023.

“Lower currents mean thinner wires and less copper required, saving cost and weight,” says David Alexander, senior research analyst with Navigant Research. “Today, the cost of power electronics has come down to the point that there are fewer barriers to installing multiple voltage subsystems, thus increasing the cars’ efficiency without the need to implement full hybrid or plug-in electric capability.”

https://www.todaysmotorvehicles.com/...ularity-12714/

And,

“But 12-volt systems are becoming inadequate for modern vehicles, says Sam Abuelsamid, a senior analyst at Navigant.

“We’ve got so many things in the vehicle today that are demanding electrical power,” he says, from advanced safety technology to convenience features.

That’s why automakers including Fiat Chrysler Automobiles (FCA), Mercedes-Benz, and Volkswagen have started designing vehicles using 48-volt systems, which CR calls mild hybrids. The technical changes are relatively minor. Cars get an electric generator instead of an alternator, and a larger battery and regenerative brakes.

Why are they making the change? Because a 48-volt system can save fuel, reduce emissions, and increase power, which helps automakers meet stricter worldwide fuel economy and emissions standards without sacrificing performance. Beyond the power boost and fuel savings, 48-volt systems don’t add as much up-front cost as true hybrids, such as the Toyota Camry Hybrid.”

https://www.consumerreports.org/auto...lt-technology/

He also noted this incredibly incisive article:

https://www.extremetech.com/extreme/...trical-systems

[John]

3) In talking this weekend with our “Janet C” — who is more connected to the top of the Corvette team than I ever will be, she said...

With the massive changes coming to the C8, specifically its conversion to a mid-engine platform, it can not have anything less than current ‘state of the art’ component systems.”[/B]

Concisely and accurate said! Thank you Janet.

[John]

To Power the Future, Carmakers Flip on 48-Volt Systems

A Volkswagen Passat fitted with a 48-volt system from Delphi. Mild hybrid systems that use 48-volt components can increase fuel economy by up to 15 percent and cost $1,000 or less per vehicle.CreditJohn F. Martin for Delphi Technologies





Image system from Delphi. A Volkswagen Passat fitted with a 48-volt system.

Mild hybrid systems that use 48-volt components can increase fuel economy by up to 15 percent and cost $1,000 or less per vehicle.CreditCreditJohn F. Martin for Delphi Technologies

By Norman Mayersohn

• Feb. 8, 2018

While automakers sketch out a world of sleek and silent electric cars or even self-driving pods that are more den than dragster, the all-electric future is further off than it may appear.

Car companies, starting with Volvo last summer, have laid out plans to electrify entire lineups of vehicles. But the fine print makes it clear that the coming decade and beyond will focus not just on massive battery packs powering electric motors, but also on adding a little extra juice to the venerable internal combustion engine.

Increasingly, that juice will arrive in the form of new electrical systems built to a 48-volt standard, instead of the 12-volt systems that have dominated since the 1950s. Simpler than Prius-type drivetrains and less expensive than Tesla-scale battery power, the new electrical architecture both satisfies the demands of cars made more power hungry by their gadget load and enables the use of lower-cost hybrid drive systems.

Earlier proposals to take cars to a 42-volt standard fizzled for cost reasons, but recent regulatory developments and the hardware that will one day make autonomous cars feasible have reignited the urgency.

Besides the drop in battery prices and control electronics, other factors have made 48-volt technology worth re-examining, said Jürgen Wiesenberger, director of the hybrid electrical vehicles unit at Continental North America. “The market was not ready for them in the past because of cost, but the 2013 fuel price spike changed that,” he said.

In limited ways, 48-volt systems have already found their way into vehicles, including the Porsche Cayenne and Bentley Bentayga S.U.V.s., where they operate the antiroll bars that keep the body level when cornering hard.
Volvo made headlines with its plans to electrify its entire vehicle lineup, but those plans include hybrid systems that complement the internal combustion engine. CreditFred R. Conrad for The New York Times



Volvo made headlines with its plans to electrify its entire vehicle lineup, but those plans include hybrid systems that complement the internal combustion engine.CreditFred R. Conrad for The New York Times
But the more integrated applications of the technology, amounting to what’s known as a mild hybrid system, offer the greatest value — up to 70 percent of the benefit of a full hybrid at 30 percent of the cost, according to industry analysts. Continental projects that 48-volt mild hybrid systems will account for 14 percent of global new vehicle sales in 2025, as sales of vehicles powered exclusively by gasoline or diesel engines drop to 65 percent.

Volvo grabbed headlines in July when it announced that it would electrify its entire model range, offering — at minimum — an electric motor to assist its piston engine in every new Volvo released from 2019. Volvo will use the 48-volt standard for its mild hybrid vehicles: those that allow the internal combustion engine to shut off while coasting or still, then kick back on when accelerating.

Audi, which is bringing 48-volt systems to the 2019 A7 and A8, replaces its conventional alternator with a larger, water-cooled alternator-starter. Rather than merely charging the battery and powering accessories, it restarts the warmed-up V6 engine after it shuts down at a stoplight and recaptures energy when slowing down to charge a lithium-ion battery in the trunk.

This design has another trick up its sleeve: It will also start the engine after the car goes into an engine-off coasting mode at speeds between 34 and 99 miles an hour, for up to 40 seconds, all in the cause of saving fuel.

Power gains are possible, too. In the SQ7, a diesel S.U.V. that Audi does not currently sell in the United States, an electric motor drives a vane-type supercharger. Similar in operation to a turbocharger, this device delivers its power boost at low engine speeds without the lag of an exhaust-driven turbo. And Mercedes-Benz is equipping the new in-line six-cylinder engine of the 2019 CLS 450 with its EQ integrated starter-generator system. In this design, the electricity is produced in the space between the engine and transmission. In motor mode, it adds 21 horse power and 184 pound-feet of torque for quick getaways, and it can take over for the gas engine at a steady-state cruise.

And 48-volt mild hybrid systems can work in heavy-duty applications: Fiat Chrysler will follow the belt-alternator approach with its eTorque system in Ram pickups and the Jeep Wrangler.

Why 48 volts? Settling on this level holds the electrical system under the 60-volt safety threshold of what is considered high voltage, where power cables must be orange and special connectors, costing 10 times as much, are required, said Mary Gustanski, chief technical officer of Delphi Technologies.

“In 2025, more than 95 percent of vehicles sold globally will still have internal combustion engines,” said Mary Gustanski, chief technical officer of Delphi Technologies. “So even in 2030, 48 volts will be part of the mix.”CreditKarl Nielsen for Delphi Technologies.
For now, the more powerful systems run alongside the traditional 12-volt electronics rather than replacing them altogether. This dual-voltage strategy avoids the need to redesign simple, reliable components like the motors that open windows and adjust seats.

“A full switch-over makes no sense,” Oliver Maiwald, a senior vice president for powertrain technology at Continental, a major industry supplier, said. “I don’t foresee a need to redesign these low-tech, low-cost parts.”

The advantages of the new 48-volt systems are considerable. They offer fuel economy improvements of up to 15 percent, Ms. Gustanski said, and would cost an automaker between $650 and $1,000 to add to the vehicle — well under the approximately $3,000 it costs to install a full hybrid system. Powering a supercharger electrically can bring a 30 percent gain in torque at low engine speeds, at an added cost of about $250. And there are still more potential applications for 48-volt systems: Electrically heated catalytic converters, for example, could be an important advance in reducing cold-start emissions.

There’s little question that the automobile will be increasingly dependent on electric power to meet fuel economy mandates and carbon dioxide limits. Battery electrics, shrinking in cost and growing in range, will be part of the solution. So will plug-in hybrids, which pack enough battery reserve for the needs of most daily commuters.

But skeptics may wonder why engineers are devoting so much effort to developing the mild hybrid systems that could be seen as stopgap measures on the path to a fully electric vehicle fleet.

It is the reality of how long it takes for the automotive fleet to turn over that really clarifies the picture. A forecast by IHS Markit, an industry analyst firm, said 10 percent of vehicles built around the world seven years from now would have 48-volt systems.

“In 2025, more than 95 percent of vehicles sold globally will still have internal combustion engines,” Ms. Gustanski said. “So even in 2030, 48 volts will be part of the mix.”

https://www.nytimes.com/2018/02/08/b...-48-volts.html

[John]

Everything You Need To Know About The Upcoming 48-Volt Electrical Revolution In Cars

With each passing year, new cars get more complicated and high-tech. The new higher power requirements associated with these advancements—along with ever-stricter emissions regulations—are why 48-volt electrical systems are spreading like wildfire, with experts expecting the tech to make its way into one-fifth of all cars sold globally by 2025. That’s a huge figure, but this technology isn’t exactly new. Here’s how it works.


I decided to contact two major automotive suppliers, Delphi and Continental, to get a better understanding of what these 48-volt systems do and why they’re just now becoming popular. It comes down to two reasons: first and foremost is helping cars meet emissions regulations, and the second is providing more power to the features buyers expect.

Lifting The Power Burden


Delphi’s E-charger (electric supercharger), a 48-volt compressor that takes air from the airbox and uses it to spin up the turbo.

Over the last decade or so, automakers have been replacing traditionally mechanically-driven components with more efficient parts like electric power steering racks, electric brake vacuum pumps and electric water pumps.

On top of that, especially in Europe, automakers have been adding in a ton of new infotainment options, and also driver-assist safety features like adaptive cruise control, lane keep assist, blind spot monitoring, etc. Plus, you’ve still got heated seats, heated steering wheels and heated windshields. Needless to say, standard 12-volt electrical systems are being stretched thin; so 48-volt systems are stepping in and help accommodate the need for more on-board power.

This is especially true on luxury cars. The Bentley Bentayga, for example, uses the 48-volt battery to drive an electric sway bar system for better handling, and Audi is using the pack to power an electric supercharger.

Delphi’s vice president of engineering, Mary Gustanski, told me the latter technology can be a huge improvement to vehicle launch capabilities. The company’s own “E-charger” on a Honda Civic spools up the vehicle’s turbo during a stop/start event and at low engine speeds to essentially eliminate turbo lag and smooth out low rpm torque deficiencies, provide up to a 25 percent increase in low end torque and 30 percent better acceleration.

So 48-volt systems can mean more electronic gizmos inside the car, but it can also mean more performance under the hood.

How It Works



Photo Credit: Delphi

Despite what you may have read about 48-volt systems, the 12-volt battery that powers all your car’s lights, engine accessories and infotainment, isn’t going anywhere anytime soon.

That’s because instead of replacing your current electrical architecture entirely (like the auto industry contemplated doing with 42-volt systems in the 1990s), upcoming 48-volt designs complement it in what is essentially a mild hybrid arrangement. In other words, a new electric motor and 48-volt battery are simply added onto the combustion engine and normal 12-volt battery, similar to what you might have found in General Motors’ BAS hybrids of the late 2000s like the Buick LaCrosse or Saturn Aura.

Similar to these older GM electrified powertrains, most new dual-voltage mild hybrid designs (like the 48V system in the Renault Scenic) consist of three main components: a Belt Alternator Starter (also called a Belt-driven Starter Generator or Motor Generator Unit, MGU), a DC-to-DC converter, and a higher voltage battery.

These three components are meant to easily adapt to electrical systems and packaging environments of regular, non-hybrid cars, with the MGU replacing a traditional alternator on the front end accessory drive, and the DC-DC converter and battery taking up a small amount of space in the trunk.

This makes 48-volt mild hybrids a relatively cheap, easy and lightweight way to get, as Gustanski told me, “50 to 70 percent of the benefit at 30 percent of the cost [of a full hybrid].” That 50-70 percent translates to fuel economy improvements of about 10 to 15 percent.

Continental agrees, saying its initial tests show a 13 percent fuel economy benefit in the NEDC drive cycle, but that real world fuel economy could increase by a whopping 21 percent—enormous gains for a simple and easily implemented system.

Lithium Ion Battery Pack And DC-To-DC Converter


Delphi: The design in the car shown above is a prototype that Delphi is bringing to CES this year. The battery, DC-to-DC converter, fuses and battery controller don’t take up a lot of room, and in a production model they’d be tucked away, likely against the back of the rear bench, over to the side or even under a loading tray.

On Continental and Delphi’s 48-volt systems, the battery is a lithium-ion unit about the size of a shoebox (the black box above). The sub-1 kWh battery pack sends juice to a small 12-volt lead-acid battery via a trunk-mounted DC-to-DC converter (the silver box with the fan), which steps down the voltage to power the car’s 12-volt accessories.

Why 48 volts for the bigger battery? Gustanski told me that it comes down to power and cost. A 48-volt battery can provide four times the on-board power of a 12-volt battery, which means it can be used to fire up a multitude of high-draw accessories like fans, pumps, electric power steering racks and compressors, which can now work more efficiently. In addition, there are benefits to wire-harness size and weight (presumably because of lower current draws through the wires at these higher voltages).

Gustanski admits that an even higher voltage battery could offer even more capability, but federal standards require costly shielding, conduits (the orange ones you see in many hybrids) and connectors in any automotive electrical system above 60-volts (above which the system becomes officially “high voltage”). Keeping voltage below that threshold means the total cost of these mild hybrid systems can remain between about $800 and $1,200.

That’s important because, as Gustanski told me, the “rule of thumb” for what automakers are willing to pay for fuel-saving technology is about $50 to $100 per percent MPG gain. At 10 to 15 percent increased mileage, these mild hybrid systems are right in that ballpark.

Motor Generator Unit


Like an alternator, the motor generator unit is connected to the engine’s crankshaft via an accessory belt, except the 48-volt unit is often liquid cooled and has special tensioners to accommodate the fact that torque will be applied by the MGU and also to the MGU.

In the first case, the approximately 10 kW unit acts as a motor, receiving current from the 48-volt lithium-ion battery in the trunk through an inverter, which changes DC power to AC to drive the motor.

That motor then turns the gasoline or diesel engine over via the drive belt. This then either quickly fires up the combustion engine after a start/stop event (a 12-volt starter remains for cold starts), provides a “boost” of up to around 100 lb-ft of torque to the engine to improve acceleration performance (particularly after a start/stop event), sends calculated torque pulses to the engine to reduce vibration of start/stops, or reduces engine loads at other strategic times to maximize fuel economy.




The unit doesn’t only act like a motor and send torque to the crankshaft—as its name implies it’s also a generator, receiving torque in order to fulfill its most basic duty of generating electricity for the 48-volt battery pack in the back of the car. This happens not only when the engine is on and spinning the belt (like with a conventional alternator), but also when the engine is off and the vehicle is coasting or braking.

This means the internal combustion engine is able shut off the fuel supply, and the wheels actually rotate the internal combustion engine through a locked torque converter. The belt from the motoring engine’s crankshaft then spins the unit, which creates energy for the 48-volt battery.

Thus, the unit acts not just to seamlessly start the car after a start/stop event, perform the alternator’s charging duty, and help reduce the load on the engine by exerting torque on the crankshaft, but it also allows for regenerative braking.

Different Levels Of Mild Hybrids


Slide from Continental

Delphi’s Mary Gustanski told me that, though the company is focusing on MGU-driven mild hybrids that run off the accessory belt (called a “P0" mild hybrid), these low-cost systems are simply a “pathway to EVs,” with the next step likely being “P2.”

P2 mild hybrids, like Mercedes’ inline starter generator system, are significantly more expensive, requiring both major changes to the vehicle packaging environment—as the Motor Generator Unit is now between the engine and transmission—and additional components like clutches. The goal with P2 is to allow the motor to power the wheels without having to turn over the engine, thus reducing drag and improving efficiency.
Continental’s P2 design shown in both pictures above features a drivetrain pulley sandwiched between the engine and transmission, and isolated from both components by two clutches. The MGU is off to the side, and sends torque to the pulley and also the AC via a belt.

To power the car with only electric power without having to drag along the non-running engine, the engine-side clutch opens, and the motor spins the transmission input shaft via the belt and drivetrain pulley.

During a start/stop event on a hot day, both clutches can open, and the unit can send power only to the AC compressor without moving the vehicle or turning over the engine.

Though making space for P2 mild hybrids would be a significant undertaking, and there are more components than in the P0 system that will soon find its ways into many cars around the globe, the ability to drive a car under only electric power, and to run AC with without the engine on could offer major fuel economy and comfort-related benefits.

It’s All For Better Efficiency


Traditional belt-driven AC Compressor. Photo: Dens
As reps from Continental and Delphi told me, 48-volt drive systems are becoming popular right now for one primary reason: to meet fuel economy and CO2 regulations, particularly those in the EU and China, which require 95 grams of CO2 per kilometer by 2021 and 117 grams of CO2 per kilometer by 2020, respectively. The U.S.’s 54.5 MPG requirement by 2025—equivalent to about 101 gram per kilometer—is also looming.


Photo: Delphi. Original data source: IHS

Running accessories off of 48-volt electricity instead of 12-volts is thriftier not just because of reduced losses (the same reason why we transmit power through power lines at high voltages), but also because, as Gustanski told me, pumps and fans run more efficiently at higher voltages. More importantly, though, is the fact that the 48-volt power supply provides enough electrical power to power devices traditionally spun by the engine’s accessory drive.

Decoupling accessories like water pumps and air conditioning from the engine reduces parasitic drag, and more notably, allows the accessories to set their own duty cycles based on vehicle and customer demands, not simply based on the engine RPM.

For example, maybe it’s the dead of winter and you’re towing a trailer up a hill at 4,000 RPM. On a traditional car, that water pump—driven by the engine— would be spinning very quickly and sending lots of coolant through the engine. But, since it’s cold outside, the engine may not need as much coolant flow to keep the engine happy. So with an electric water pump, you could theoretically save energy by throttling back that pump based on cooling requirements.

Another example, which Gustanski mentioned, is a 48-volt AC system running the compressor at a low speed during highway cruising rather than at very high speeds governed by the engine RPM. The point here, is that allowing components to run at speeds based on required output, and not simply based on engine speeds offers a significant benefits to efficiency.



Gustanksi even mentioned using the 48-volt power supply to more quickly heat up a catalyst in a diesel exhaust system to reduce emissions. Between this, the added luxury electrical features that can now be accommodated, regenerative braking, boost from the electric motor to reduce engine load, more efficient accessories that don’t depend on engine speed, and reduced turbo lag from an electric supercharger, it’s safe to say the benefits of this tech span far beyond that little 10 to 15 percent fuel economy improvement figure.

It’s no wonder industry expert IHS says the market for 48 volt mild hybrids is expected to increase ninefold by 2025, with a total of 14 million vehicles expected to enter production.

That’s great news for suppliers like Delphi and Continental, but it could also be also good news for consumers, who are promised better fuel economy, more provisions for high-tech electronic options, and increased performance —all at relatively minor costs to MSRP, rear storage space and overall weight.

https://jalopnik.com/everything-you-...olt-1790364465

[John]

This article originally brought to our attention thanks to Bikerjulio:

Cars with 48V electrical systems to gain popularity

Resarch group predictions 13.5 million in vehicle system sales by 2023.

January 27, 2014

Cars/Light trucks Electric vehicles Electronics Economy
Cars and trucks that produce more power for peripheral systems will skyrocket in popularity by 2023, a research group believes.

As auto manufacturers continue to replace mechanical systems with electrical components, particularly in stop-start vehicles (vehicles that shut off their engines at red lights and other stopping situations), the demands for power have begun to outstrip the capabilities of traditional battery systems.

Increasing the voltage of certain subsystems by four times – going from a nominal 12V to a 48V system – means that the same power can be delivered with one-quarter of the current. According to a new research brief from Navigant Research, sales of light-duty vehicles with 48V electrical subsystems will reach nearly 13.5 million by 2023.

“Lower currents mean thinner wires and less copper required, saving cost and weight,” says David Alexander, senior research analyst with Navigant Research. “Today, the cost of power electronics has come down to the point that there are fewer barriers to installing multiple voltage subsystems, thus increasing the cars’ efficiency without the need to implement full hybrid or plug-in electric capability.”

Sales of new cars with 48V systems are expected to be slow until the end of the decade, then ramp up quickly from 2020 to 2023, according to the report. As the result of aggressive fuel economy and emissions regulations, Western Europe is expected to be the leading market for 48V system sales over the next 10 years. Meanwhile, German luxury vehicle manufacturers have collaborated to develop a 48V system that sets the foundation for more capable stop-start systems that will enable other electrification features.

The report, “48-Volt Systems for Stop-Start Vehicles and Micro Hybrids”, analyzes the opportunities and challenges for 48V electrical subsystems in vehicles. The study provides an examination of the reasons to move to a higher voltage for stop-start component systems, including the options for energy storage. Global forecasts are provided for light duty vehicle sales that feature 48V systems by world region through 2023. The report also provides a summary of the benefits, drivers, and market barriers for 48V systems, as well as profiles of the key market players that are promoting this technology. An Executive Summary of the report is available for free download on the Navigant Research website.

Source: Navigant Research

https://www.todaysmotorvehicles.com/...ularity-12714/

[John]

This article originally brought to our attention thanks to Bikerjulio.

Why Cars Are Moving to 48-Volt Electrical Systems

• By Bill Howard on April 26, 2017 at 11:30 am

Many cars will soon have 48-volt electrical systems. They’ll power stop-start motors, hybrid motors, and turbochargers, allowing for smaller engines with better fuel economy and performance. They’ll handle accessories ranging from mechanical or hydraulic power to electric power such as power steering, power brakes, water pump, radiator cooling, and air conditioning.

These will be combination 12- and 48-volt systems with 12 volts for traditional lighting and infotainment, 48 volts for more power-hungry components. But don’t freak out: The 12-volt system isn’t going away any time soon.
What 48 volts can do: low-cost mild hybrid

Bosch, Continental, Delphi, and Valeo are among the key components makers working to provide 48-volt systems to automakers.

Odds are your next car will have a start-stop system, probably 12 volts, and a slightly larger 12-volt battery. When you come to a stop at the light, the car shuts down after a couple seconds. It fires up again with a little hesitation, a couple tenths of a second, on some cars. At a light, the car feels poky. It makes you nervous if you’re at a stop sign trying to get across the street with crossing traffic getting closer. With 48-volt stop-start:

• The starter is replaced with a beefier 48-volt device called a motor generator unit(MGU), belt alternator starter, or belt-driven starter generator.
• A 48-volt lithium-ion battery pack, typically in the trunk.
• A DC-to-DC converter.

Effectively, you’ve got a mild hybrid powertrain, one that works in parallel with the combustion engine. Backers say it provides two-thirds the benefit of a full hybrid at a third the cost. Fuel economy increases by 15 to 20 percent.

What 48 volts can do: e-charger for faster acceleration


Valeo electric supercharger.

A four-cylinder car with a turbocharger has the performance of a V6 without a turbo. But there’s lag here, too, those tenths of a second while the turbo spools up to 100,000-200,000 rpm and forces more and more air into the engine. Virtually every review describes turbo lag as “barely noticeable,” which really means “noticeable” when you want to pass on a two-lane road, or get over the railroad tracks when the signal lights start blinking.

Enter the electric turbocharger / electric supercharger, or e-charger. Rather than wait for exhaust gases to eventually bring the impeller up to speed, an electric motor makes it happen more quickly so that the lag is truly barely noticeable. This, too, requires a 48-volt system.

Audi’s electric supercharger concept cars



Audi has electric supercharger in its Q8 Sport Concept vehicle. Earlier, it put one in the SQ7 TDI (diesel, schematic above). A traditional turbocharger is driven by exhaust gas and a supercharger is driven by an engine-powered belt; both force air under pressure into the car’s intake manifold. Some automakers called their e-charger an electric turbocharger, others an electric supercharger.
Delphi’s lower-cost hybrid system


Delphi motor/generator with cooling hoses.

Delphi is one of the automakers thinking about a multi-component solution to delivering a lighter, more efficient drivetrain. It starts by replacing the starter motor with a 48-volt motor-generator that starts and restarts the car, provides extra power beyond what the combustion engine offers, and recharges the 48-volt lithium-ion battery in the trunk. Delphi’s motor-generator is the same size as a regular starter motor (plus two cooling hoses; photo inset), so it can be added to an existing car without having to move other components such as the radiator.

A 48V e-charger is added to complement the car’s existing turbocharger. Finally, the engine is modified for cylinder deactivation, which Delphi grandly calls Dynamic Skip Fire. At cruise on level roads, a car with Dynamic Skip Fire might fire, on average, only one and a quarter cylinders per revolution.

https://www.extremetech.com/extreme/...trical-systems

[John]

This article originally brought to our attention thanks to Bikerjulio.

Why Your Next Car Might Use 48-Volt Technology

Better fuel economy, more power, and improved durability. What’s not to like?

By Keith Barry
April 23, 2018
413 SHARES


Automakers worldwide increasingly talk about electrifying their fleets, but it doesn’t mean every future car or truck will need to be plugged in. Instead, the first wave of this advance is 48-volt technology.

The new onboard battery systems can provide extra juice to run infotainment and advanced safety systems that are increasingly complex and thirsty for power. Other benefits include decreased emissions and even improved acceleration.

Experts tell CR that 48-volt systems are an easy way for automakers to improve performance, fuel economy, and even durability.

Choosing It, Insuring It, Driving It

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Join Why 48-Volt?

Most cars today contain the typical 12-volt electrical system that relies on an alternator to convert the engine’s power into electrical current. That current charges the vehicle’s starter battery and runs all the vehicle’s electrical components, including lighting, infotainment, and safety systems.

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But 12-volt systems are becoming inadequate for modern vehicles, says Sam Abuelsamid, a senior analyst at Navigant.

“We’ve got so many things in the vehicle today that are demanding electrical power,” he says, from advanced safety technology to convenience features.

That’s why automakers including Fiat Chrysler Automobiles (FCA), Mercedes-Benz, and Volkswagen have started designing vehicles using 48-volt systems, which CR calls mild hybrids. The technical changes are relatively minor. Cars get an electric generator instead of an alternator, and a larger battery and regenerative brakes.

Why are they making the change? Because a 48-volt system can save fuel, reduce emissions, and increase power, which helps automakers meet stricter worldwide fuel economy and emissions standards without sacrificing performance. Beyond the power boost and fuel savings, 48-volt systems don’t add as much up-front cost as true hybrids, such as the Toyota Camry Hybrid.

"The addition of 48-volt batteries can be good value for consumers because they support the latest tech features and boost fuel efficiency at a reasonable price point,” said Shannon Baker-Branstetter, senior policy counsel for energy and environment at Consumers Union, the advocacy division of Consumer Reports.


For example, a 48-volt system comes standard on the 2019 Ram 1500 outfitted with the smaller 3.6-liter engine. It adds only $800 to a Ram equipped with the larger 5.7-liter V8 engine, and it can boost fuel economy up to 10 percent, FCA says. It also adds up to 130 lb.-ft. of torque, which translates into better initial acceleration and more power for hauling and towing.


The chassis of a 2019 Ram 1500, showing its 48-volt system.

The 48-volt battery system allows the 2019 Audi A6 to shut off its engine while coasting to save fuel. The setup also makes the car’s auto stop/start function—which shuts off the engine when the car is stopped—much less intrusive. The engine restarts faster and the air conditioning stays on while the engine is off, which addresses a common consumer complaint.

“Ultimately, the biggest change in performance I think the U.S. consumer is going to appreciate is the feel of the engine start-stop performance,” says Brian McKay, director of powertrain technology and innovation for Continental North America, which supplies Audi with its 48-volt system. According to McKay, Continental’s system adds only about 33 pounds to the weight of the vehicle.

Consumers will also see a vehicle’s electric-powered convenience features perform better, McKay says, with the vehicle “being able to warm up your seats faster, defrost your windshield faster.” A 48-volt system will also provide enough amperage to run power tools, which is a feature McKay expects to see used on pickup trucks. Already, FCA says the Ram 1500 can provide up to 400 watts of power.


The Audi A6 uses a 48-volt system, which promises smoother start-stop and more power for high-tech features. A 48-Volt Future

Drivers should expect even more 48-volt advances soon. “Once you have a 48-volt infrastructure available in your car, you can start doing some interesting things with it,” McKay says.

Audi already uses the 48-volt system in its A8 sedan to power small electric motors in its adaptive suspension. In Europe, the 48-volt 2018 Audi SQ7 TDI uses an electric compressor to help its twin turbochargers work faster and better, improving acceleration.

A 12-volt electrical system just wouldn’t have enough juice to power these systems, Abuelsamid says. That’s also the case with the energy-hungry sensors and computers necessary for the next generation of autonomous vehicle technology.

In the near future, he expects more belt-driven engine components—like water pumps and radiators—to get electrified as 48-volt systems become more commonplace.

“They should also be more reliable in the long term, because they’re not dependent on that belt,” he says. Because electrical systems often have fewer moving parts than traditional approaches, they have been found to be more reliable over time.

According to McKay, the 48-volt system itself shouldn’t cause any maintenance headaches. The whole system, including the battery, “will last the lifetime of the vehicle,” he says.

We are eager to put those claims to the test when we purchase a Ram 1500. As for reliability, we will see what CR members say in future surveys.

https://www.consumerreports.org/auto...lt-technology/

[JDMilw]

Thank you John! Excellent and informative posting!

[John]

Happy to help, but the credit in this area primarily goes to BikerJulio — who got me originally excited about learning more about this massage jump shift in the automotive industry.

Thanks also to my friend Janet C for succinctly focusing the issue of why the 2020+ Corvette needs to be part of this sea change.

[Bikerjulio]

I'm blushing over here

Anyway John is being too modest. This investigation of mine was kicked off by post #28 in the "electrical problem" thread when he said:

Perhaps, again if this really is happening for the electrical reason noted in the GM Authority article, since we have repeatedly heard that the top version is going to have electrical motors powering the front wheels, maybe while GM was working on that top version, they decided in order to make that system work best, it needs to be by converting the whole electrical system from a 12V system to a 24V — or even a 48V system.

As soon as I started doing a little research on 48V, it seemed likely to me that Corvette would adopt it for the C8. Nothing to do with front motors, but for a host of other reasons.

[Busa Dave]

There you go excellent thread John. The Supply Chain must be completely integrated into this process as well. This automotive as in my industry military aerospace the Infrastructure Must be In Place for future planned upgrades or Type Version/Block upgrades as we say "releases" (maybe a hybrid in the future) who knows but my money says yes. Notwithstanding the infrastructure of the electrical platform must "scalable" period -- for this to happen been around this almost my entire working life. GM is Very Smart to get this correct! A good analogy would be the foundation of a house---no matter what you put on top of it the structure will always be limited to the capabilities of the foundation.

[Milliwatt Rob]

If 48 v is needed to support start-stop system, that suggests strongly that the C8 will have start-stop.

All I can say is, start-stop better be defeatible. A new OBD2 plug in may be needed to turn this off.

[JB]

I turn off stop start with the first shut down. I hate that system but most people dont and it does add 10 percent fuel efficiency.....which if i cares about Id have waited for the tesla i had on order.

the tesla company kept delaying their vehicle so I bought something else and cancelled my long delayed tesla order......

this is cool tech and im sure the 48 volt system will be quite an improvement...

where we end up with a 48 volt system i sure will be impressive,

thanks for the details in this thread.

[Frenzy36]

This is all welcome news and hopefully will be incorporated into the ME. Thanks John and Bikerjulio. This will open doors for a custom sound system with some serious subwoofers also! Yeah ! With this kind of good news it will make the wait well worth it.