GM claims 'breakthrough' will make vehicles lighter, help fuel mileage

[jpd80]

GM claims 'breakthrough' will make vehicles lighter, help gas mileage
LINK
General Motors plans to accelerate the replacement of steel with aluminum after researchers achieved what the company described as a "breakthrough" in welding technology.

GM hopes the technological advancement will boost fuel economy by making its vehicles lighter. Aluminum is lighter than steel, making it an enticing alternative when it is not too expensive. But several hurdles remain for aluminum, including production challenges.

GM believes it has solved one of those challenges: the frustrating process of welding aluminum body panels.

Blair Carlson, GM's lab group manager for lightweight material processing, said researchers at the company's technical center in Warren developed a spot-welding technology that uses a special electrode to help two pieces of aluminum clamp together.

He said the technology also involves a proprietary process for controlling electrical current and cleaning the electrodes, which use protruding rings to pierce the hard oxide surface of aluminum, enabling the metals to fuse together.

GM has already used the technology to use aluminum in the hood of the Cadillac CTS-V sedan and the lift gate of Chevrolet Tahoe and GMC Yukon hybrids.

"There's going to be a significant increase in the application of aluminum in our vehicles in the next five years," Carlson said. He declined to say how much weight GM believes it can save in the average vehicle using the technology.

Carlson said researchers happened upon the spot-welding technology by accident when they experimented with software during a test.

"As it turned out, it was like, 'Wow, that really worked, what did we do?' " Carlson said. "We had to go back and figured out what we did, and that actually led to a breakthrough in one of our patents in the area of controls."

GM has dabbled in aluminum welding before, dating back to the EV1 in 1996 and some SUVs in 1999. But the process needed to be refined.

While this is great news I think Jaguar, land Rover and now Ford is moving on with
Aluminium using a mixture of rivets, adhesives and welding.....

[Drizz06]

I work on land rovers all day and they are spot welded alu body's.

[jpd80]

Originally Posted by Drizz06

I work on land rovers all day and they are spot welded alu body's.

Jaguar is using special rivets and adhesives on XK, XF and XJ but the tech came for the Land Rover engineers...

3100 SELF-PIERCING RIVETS ARE USED

The new XJ’s body structure is a masterpiece of advanced, intelligent technology. A ‘team’ of 100 robots applies just over 3100 self-piercing rivets, and more than 100 metres of aerospace industry-sourced epoxy adhesive to bond the aluminium pressings, castings and extrusions together to create the very stiff and durable structure. Painstaking research and analysis, along with thousands of hours of computing time, have enabled Jaguar’s engineers to improve the construction process, optimising the use of different grades and gauges of aluminium.

And the new Range Rover is using the same tech too...

The fourth-generation, dramatically slimmed down Range Rover leads its ancestors.
The car’s aluminum body is riveted and bonded using aerospace engineering processes. On the Solihull body line, 328 robots look after major areas of assembly, including application of 3722 rivets of 17 types. More than 160 m (525 ft) of adhesive is applied. The car uses what is claimed to be the largest single automotive stamping in the world. Saving 3 kg (6.6 lb), the body side eliminates joints to give better structural integrity. The best aerodynamic Cd of the range is 0.34, a 10% improvement, the front grill having active vanes.

[SteveJH]

Don't welds weigh less than rivets? I seem to recall welding leading to a revolution in another industry (shipbuilding).

[Nikked]

Originally Posted by SteveJH

Don't welds weigh less than rivets? I seem to recall welding leading to a revolution in another industry (shipbuilding).

Rivits are usually used when two sections of different steels meet.

Gluing and riveting is also preferred as repair shops don't have the welding equipment to accurately recreate what the factories do.

[Luke Plaizier]

Originally Posted by SteveJH

Don't welds weigh less than rivets? I seem to recall welding leading to a revolution in another industry (shipbuilding).

Yes. We need a war and an aluminium welding revolution so we can pump out a bucket load of "Liberty Cars".....


Lukeyson

[2011G6E]

Yes, aluminium can be rivetted or glued...but they are talking about welding it properly on a large scale and cheaply done for mass production. That's been a real nightmare for the car makers.

[mik]

i`d rather have steel for a car body i think, yes it can go rusty, but it`s pretty easy to repair and takes a fair bit to dent up a panel.

[madmelon]

Originally Posted by mik

i`d rather have steel for a car body i think, yes it can go rusty, but it`s pretty easy to repair and takes a fair bit to dent up a panel.

Aluminium can be made stronger for less mass. For example, if the panels were made the same mass (by increasing the thickness of the sheet metal), it would have approximately 8 times the stiffness, despite only having 2.89 times the thickness. Or if you wanted a panel 50% stiffer than a steel equivalent, the aluminium would need to be 65% thicker but would only be 57% of the mass.

Don't be fooled into thinking that an aluminium panel is easier to dent because it is a less stiff material- its low density more than makes up for it's lower stiffness.

[jpd80]

Jaguar and land Rover are so far in front of this with self piercing rivets and adhesives that bond stronger than steel,
I think GM is riding for a fall as I recall J/LR looked into this and it was a real liability if weld quality failed..
there's much less potential exposure to quality issues with rivets and adhesives than welding going awry....

[zilo]

Build cars with complex welds and exotic adhesives and they will be written off much easier in the event of a minor collision.

You only have to look at chassis rails these days, yes they can be repaired, but the labour costs write the car off way too easily in my opinion.

[boris]

Please, there was an American university that in 2007 invented thermo forging for the car industry with uses carbon fibre to form chassis and body panels with the strength and rigidity of titanium. They built car bodies that were 40% of the weight at 60% of the cost. The car industry didn't pick it up because they have too much money 'invested' in steel. Please, you wanna claim 'break through', go carbon fibre then I'll take notice, but aluminium, talk to the hand!

[Flat Top]

Gm go talk to (VAG) Audi ??? please breakthrough what spin!!! VF should be using ali bonnets etc no big deal

[jpd80]

Originally Posted by boris

Please, there was an American university that in 2007 invented thermo forging for the car industry with uses carbon fibre to form chassis and body panels with the strength and rigidity of titanium. They built car bodies that were 40% of the weight at 60% of the cost. The car industry didn't pick it up because they have too much money 'invested' in steel. Please, you wanna claim 'break through', go carbon fibre then I'll take notice, but aluminium, talk to the hand!

And that work on carbon fibre brought the cost way down from over 300/kg to under $30/kg but the
problem is that carbon fibre is still around $22/kg where as steel is around $5/kg and Aluminium somewhere in between.
The fact tha Mulally ordered a thorough review of the costs of composites which concluded that they are still too expensive
is the main reason why you're seeing the push on Aluminium in next F150 , having a global glut on supplies also helps too..

[boris]

Originally Posted by jpd80

And that work on carbon fibre brought the cost way down from over 300/kg to under $30/kg but the
problem is that carbon fibre is still around $22/kg where as steel is around $5/kg and Aluminium somewhere in between.
The fact tha Mulally ordered a thorough review of the costs of composites which concluded that they are still too expensive
is the main reason why you're seeing the push on Aluminium in next F150 , having a global glut on supplies also helps too..

Ah but, thermo forging was able to use cheaper forms of carbon fibre and the over all cost of building a chassis, assembling it etc was 60% of the cost of steel, so while the raw materials may cost more because of the manufacturing process it ended up cheaper. However their are a lot of industries/jobs that rely on the car industry using steel/aluminium. Thermo forging is is far less labour intensive and tooling less expensive and last longer.

[Bossxr8]

Originally Posted by FPV GTHO

You can only lower the Cd so much by only doing the front bumper and maybe the bonnet. Significant changes would need less flaring in the guards and more rake in the front windscreen, the latter of which has a snowballs chance in hell of happening.

There is probably just as good a gain controlling the airflow under the car by smoothing out the underbody, and also in controlling the airflow around the wheelwells. The Ferrari 458 excels in these areas, they have vents at the front that flows air through the wheelwells and out through a vent in the rear corner of the bonnet. Or is it the F12 Berlinetta?

Originally Posted by MethodX

Ford do the same thing. no biggie.
Computer torque control... Efi? Wonder if they invented that one...

Computer torque control referred to the variable length inlet manifold fitted for the EF. Switching the length of the inlet runners via a set of throttle butterflies controlled the torque at different rev points. But from what I can remember it was controlled by vacuum so go figure. But I guess the ECU had to compensate when it switched over.

[Rodge]

Australian made cars need to spend more time in wind tunnells, is there a wind tunnell in Australia ? FG Falcon has a coefficient of drag of 0.35 which is one of the reasons why they use more fuel than is necessary.

I don't think making some of the body panels out of aluminium is going to save much weight but it will add to the cost of production. Looks like GM are trying to curry some favour with the public...bottom line is talk is cheap, just build them and we'll see.

[madmelon]

Originally Posted by Rodge

Australian made cars need to spend more time in wind tunnells, is there a wind tunnell in Australia ? FG Falcon has a coefficient of drag of 0.35 which is one of the reasons why they use more fuel than is necessary.

I don't think making some of the body panels out of aluminium is going to save much weight but it will add to the cost of production. Looks like GM are trying to curry some favour with the public...bottom line is talk is cheap, just build them and we'll see.

Not sure where you're getting all that from...
Ford hasn't published drag coefficient data for the FG but I doubt it would be worse than AU or BA, which were 0.295 and 0.29 respectively. This has minimal impact to city driving compared to vehicle mass.

If you don't think aluminium can make a big difference- compare the X308 to the X350 series Jag XJ. They lost about 200kg through the move to an all aluminium structure whilst gaining a substantial amount of kit and structural stiffness. An even better example is the latest Range Rover to be released: some 470kg lighter due to all aluminium construction and the equivalent Discovery is expected to be some 500kg lighter.

Obviously it adds cost but there will come a time when more manufacturers are using lightweight materials than not.

[Rodge]

Originally Posted by madmelon

Not sure where you're getting all that from...
Ford hasn't published drag coefficient data for the FG but I doubt it would be worse than AU or BA, which were 0.295 and 0.29 respectively. This has minimal impact to city driving compared to vehicle mass.

If you don't think aluminium can make a big difference- compare the X308 to the X350 series Jag XJ. They lost about 200kg through the move to an all aluminium structure whilst gaining a substantial amount of kit and structural stiffness. An even better example is the latest Range Rover to be released: some 470kg lighter due to all aluminium construction and the equivalent Discovery is expected to be some 500kg lighter.

Obviously it adds cost but there will come a time when more manufacturers are using lightweight materials than not.

Autocar N.Z. quotes the SC GT at 0.35.

Yeah there's lots of noise about how much weight the very expensive process of building all aluminium cars can save but the bottom line is the all aluminium current XJ Jaguar and all aluminium Audi S8 are both significantly heavier than a SC GT, go figure...and that's before we even consider the extraordinary amount of extra cost this build process adds.

BTW Mercedes-benz also makes use of extensive aluminium in its S Class and that weigh's 2082 kg's with a full tank of fuel.
Despite all the extra costs where's the aluminium weight savings on large sedans ?

[Dr Smith]

Originally Posted by Rodge

Autocar N.Z. quotes the SC GT at 0.35.

Yeah there's lots of noise about how much weight the very expensive process of building all aluminium cars can save but the bottom line is the all aluminium current XJ Jaguar and all aluminium Audi S8 are both significantly heavier than a SC GT, go figure...and that's before we even consider the extraordinary amount of extra cost this build process adds.

BTW Mercedes-benz also makes use of extensive aluminium in its S Class and that weigh's 2082 kg's with a full tank of fuel.
Despite all the extra costs where's the aluminium weight savings on large sedans ?

Could it be that on a lwb car when you add electrically assisted boot & door closing, powered rear seats, heated seats, all the airbags, sunroof, plus any other tech, a non aluminium car would weigh even more.

[jpd80]

Originally Posted by Rodge

Autocar N.Z. quotes the SC GT at 0.35.

And that is only an estimate..... Wikki quotes 1998 AU at 0.295, 1995 Falcon 0.31, I would expect that the regular FGs are just as good if not better...

VN Commodore = 0.34
VN Group A = Less than 0.30
VT Commodore = 0.32
Monaro = 0.31
VX Commodore = 0.329
VX Commodore SS Spoiler = 0.354
VY Commodore = 0.319
VY Commodore S Spoiler = 0.326
VY Commodore SS Spoiler = 0.334
VE Commodore = 0.354
VE Commodore Series II = 0.330
VE Commodore Series II + Rear Wing = 0.35+
WK Statesman = 0.30
ECOmmodore = 0.28

XF Falcon = 0.42
EA Falcon = 0.34
EF Falcon = 0.31
AU Falcon Sedan = 0.295
AU Falcon Wagon = 0.341

2010 Toyota Prius = 0.25
2002 Toyota Camry = 0.30
2003 Toyota Camry = 0.29
2010 Toyota Camry Hybrid = 0.27
2007 Toyota Aurion = 0.301
2007 Toyota Aurion Sportivo = 0.292

[Brazen]

Originally Posted by jpd80

And that is only an estimate..... Wikki quotes 1998 AU at 0.295, 1995 Falcon 0.31, I would expect that the regular FGs are just as good if not better...

VN Commodore = 0.34
VN Group A = Less than 0.30
VT Commodore = 0.32
Monaro = 0.31
VX Commodore = 0.329
VX Commodore SS Spoiler = 0.354
VY Commodore = 0.319
VY Commodore S Spoiler = 0.326
VY Commodore SS Spoiler = 0.334
VE Commodore = 0.354
VE Commodore Series II = 0.330
VE Commodore Series II + Rear Wing = 0.35+
WK Statesman = 0.30
ECOmmodore = 0.28

XF Falcon = 0.42
EA Falcon = 0.34
EF Falcon = 0.31
AU Falcon Sedan = 0.295
AU Falcon Wagon = 0.341

2010 Toyota Prius = 0.25
2002 Toyota Camry = 0.30
2003 Toyota Camry = 0.29
2010 Toyota Camry Hybrid = 0.27
2007 Toyota Aurion = 0.301
2007 Toyota Aurion Sportivo = 0.292

Amazing how backwards the VE went. It's also worth noting that the number is a coefficient....the other factor is frontal area. Aerodynamics are a function of the coefficient AND frontal area, the smaller the car the more wind efficient it is even if it has the same coefficient number of a larger car.

[Nikked]

Originally Posted by Rodge

Yeah there's lots of noise about how much weight the very expensive process of building all aluminium cars can save but the bottom line is the all aluminium current XJ Jaguar and all aluminium Audi S8 are both significantly heavier than a SC GT, go figure...and that's before we even consider the extraordinary amount of extra cost this build process adds.

BTW Mercedes-benz also makes use of extensive aluminium in its S Class and that weigh's 2082 kg's with a full tank of fuel.
Despite all the extra costs where's the aluminium weight savings on large sedans ?

Yes, and those cars would have weighed much more with normal metals and construction...

If you wieghed the bare shells, the likes of a Jag, Audi etc would wiegh less then the FG...

[Pub247]

Originally Posted by Rodge

Australian made cars need to spend more time in wind tunnells, is there a wind tunnell in Australia ? FG Falcon has a coefficient of drag of 0.35 which is one of the reasons why they use more fuel than is necessary.

I don't think making some of the body panels out of aluminium is going to save much weight but it will add to the cost of production. Looks like GM are trying to curry some favour with the public...bottom line is talk is cheap, just build them and we'll see.

There's one in the monash uni campus in clayton... has a dyno in it aswell..... and haven spoken to the engineer that works there i can tell you that car makers do use it

[FPV GTHO]

It wouldn't surprise me if BA or FG had a rise in Cd over AU, which had a noticeably slippery profile to the front end.

[Bossxr8]

Originally Posted by Rodge

Australian made cars need to spend more time in wind tunnells, is there a wind tunnell in Australia ? FG Falcon has a coefficient of drag of 0.35 which is one of the reasons why they use more fuel than is necessary.

I don't think making some of the body panels out of aluminium is going to save much weight but it will add to the cost of production. Looks like GM are trying to curry some favour with the public...bottom line is talk is cheap, just build them and we'll see.

Ford have a pretty new wind tunnel out at the Proving Ground. Its only 2 or 3 years old. I'm betting that the 2014 upgrade will be the first Falcon to take full advantage of it as they have already stated that aero improvements will play a part in the 7-8% fuel economy improvements they are claiming for it.

[Buntz]

Originally Posted by Bossxr8

Ford have a pretty new wind tunnel out at the Proving Ground. Its only 2 or 3 years old. I'm betting that the 2014 upgrade will be the first Falcon to take full advantage of it as they have already stated that aero improvements will play a part in the 7-8% fuel economy improvements they are claiming for it.

Well if it gets the styling similar to the new Fusion, it could hit drag coefficients of the AU.

Hell the new Fusion has a better CD with .27

[FPV GTHO]

You can only lower the Cd so much by only doing the front bumper and maybe the bonnet. Significant changes would need less flaring in the guards and more rake in the front windscreen, the latter of which has a snowballs chance in hell of happening.

[Road_Warrior]

The current gen Ford Explorer uses an aluminium bonnet, so Ford must have gotten the mass production thing with ally sorted somehow.

[Mad_Pom]

Don't forget the Lotus Elise, which have being using glue Alluminium since 1996. They glued instead of rivets to avoid stress fractures and it was actually shown to be stronger