New Carbon Fiber Materials Coming to Lexus Vehicles?

Posted by Kevin on August 13th, 2017

More carbon fiber parts could be coming to future Lexus vehicles, thanks to a new process and increased in-house production — from Automotive News:

SMC represents a new manufacturing process for Toyota, even though the automaker has used similar materials for the Lexus LFA supercar. But they are specialty uses for limited-volume panels, [JP Flaharty, executive program manager for technical strategy at Toyota North America R&D] clarified.

Working with material supplier Mitsubishi Chemicals, the [carbon fiber sheet molded compound] process, which uses chopped fibers rather than long fibers, is faster and has proved far easier for Toyota to undertake in house for a mass market vehicle.

“The material we’re using is more similar in design and manufacturing conceptually to sheet metal forming,” Flaharty said. “You’re making a mold, you’re making a shape, it’s got this 3-D characteristic to it. So we’ve got a lot of know-how and a lot of understanding in how that works. We can align our capabilities to do this internally.”

The doors and deck lid of the Lexus LC was made from carbon fiber sheet molded compound, or SMC, but there’s been an even more impressive use for the material — the liftgate on the mass-market Toyota Prius Prime plug-in hybrid.

(This represents a sea change in the way carbon fiber are being used in the automotive industry, and it should only a matter of time before SMC makes its way across the Lexus lineup.)

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Comments
LDeleuran
Seeing how it's already used in the LC, I would like to know more about how much weight is actually saved. The LFA used carbon fibre for the structure. The SMC seems to be body panels only (for now?). My concerns are primarily focused on the weight of the vehicles on the GA-L platform (New LC, LS, etc.). They do not seem particularly light. Hopefully the next GS (also to be released on GA-L) will give us a better indication of the weight savings. The LS has grown significantly in size (and we don't know the weight yet) while the LC is a huge grand tourer (not expected to be light)
L
Forged carbon fiber is really a great material. Only Lamborghini uses this, with TMC now. There is also a version of Royal Oak AP watch that has a forged carbon fiber case.
S
LDeleuran
Seeing how it's already used in the LC, I would like to know more about how much weight is actually saved. The LFA used carbon fibre for the structure. The SMC seems to be body panels only (for now?). My concerns are primarily focused on the weight of the vehicles on the GA-L platform (New LC, LS, etc.). They do not seem particularly light. Hopefully the next GS (also to be released on GA-L) will give us a better indication of the weight savings. The LS has grown significantly in size (and we don't know the weight yet) while the LC is a huge grand tourer (not expected to be light)
Despite the extensive use of light weight materials the LC is still overweight for its size, just like the RC. The LC is about the same weight as many full-size 4 door Coupes. The BMW 6 is lighter, the CLS is about the same, the Panamera and A7 are heavier but because of AWD. The AM DB11 is larger than the LC but is much lighter despite having a very heavy V12.
Gecko
LDeleuran
Seeing how it's already used in the LC, I would like to know more about how much weight is actually saved. The LFA used carbon fibre for the structure. The SMC seems to be body panels only (for now?). My concerns are primarily focused on the weight of the vehicles on the GA-L platform (New LC, LS, etc.). They do not seem particularly light. Hopefully the next GS (also to be released on GA-L) will give us a better indication of the weight savings. The LS has grown significantly in size (and we don't know the weight yet) while the LC is a huge grand tourer (not expected to be light)
In the press materials, Lexus noted that the LS 500 has lost 200lbs over the old model. I would assume that is in comparison to the LS 460L because it's more comparable to the LS 500.

ssun30
Despite the extensive use of light weight materials the LC is still overweight for its size, just like the RC. The LC is about the same weight as many full-size 4 door Coupes. The BMW 6 is lighter, the CLS is about the same, the Panamera and A7 are heavier but because of AWD. The AM DB11 is larger than the LC but is much lighter despite having a very heavy V12.
LC is way too heavy for it's size.... it should truly be a ~4,000lb vehicle, if that. I respect Lexus' focus on rigidity and safety, but the consequences for being ~400lbs overweight are very real.
mikeavelli
When cars share platforms, the smaller cars always suffer with weight penalties...FM Chassis from Nissan, RC F etc....

Note the IS 300 was its own platform and only weights 3300 lbs. This is with the huge and heavy 2JZ engine!

In comparison a 1992 SC 400 weights about 3600lbs... I think considering what the LC offers in comparison I will take the weight :D

Another thing too, these cars will rarely be tracked and with this older engine, I don't think a couple hundred lbs off would benefit MPG greatly.
S
mikeavelli
don't think a couple hundred lbs off would benefit MPG greatly.
Weight reduction is the most effective way to increase MPG: losing 5% basically means 5% better MPG. Believe it or not, a 5% increase in MPG is huge in automotive engineering. Being overweight is also counterproductive to Lexus' attempt to make "sporty vehicles". We can only hope the fact that LC is overweight means a convertible is coming, otherwise it's just unnecessary over-engineering.
CIF
  • CIF
    CIF
  • August 19, 2017
ssun30
Weight reduction is the most effective way to increase MPG: losing 5% basically means 5% better MPG. Believe it or not, a 5% increase in MPG is huge in automotive engineering. Being overweight is also counterproductive to Lexus' attempt to make "sporty vehicles". We can only hope the fact that LC is overweight means a convertible is coming, otherwise it's just unnecessary over-engineering.
On the other hand, to have a strong sense of solidity, feeling of luxury, and very high refinement and peace inside the cabin requires weight. There's no way to cheat physics in that regard. Why do you think Rolls Royce and Bentley models are so heavy? Going too extreme with a lightweight philosophy risks problems with solidity, a feeling of luxury, not to mention NVH levels. Taken to a related extreme, off-road unlimited class race trucks run a minimum amount of weight, roughly in the mid 3000 lbs range for reasons of physics, so that the trucks can endure the punishment of the harsh terrain. Putting this back into context of this discussion, too much weight reduction can be detrimental to luxury class vehicles, especially in poor or rough road conditions.
S
CIF
On the other hand, to have a strong sense of solidity, feeling of luxury, and very high refinement and peace inside the cabin requires weight. There's no way to cheat physics in that regard. Why do you think Rolls Royce and Bentley models are so heavy? Going too extreme with a lightweight philosophy risks problems with solidity, a feeling of luxury, not to mention NVH levels. Taken to a related extreme, off-road unlimited class race trucks run a minimum amount of weight, roughly in the mid 3000 lbs range for reasons of physics, so that the trucks can endure the punishment of the harsh terrain. Putting this back into context of this discussion, too much weight reduction can be detrimental to luxury class vehicles, especially in poor or rough road conditions.
But we were talking about a car that is very overweight even compared to much larger vehicles, which is not good.

Lightweight materials are usually stronger than plain steel so weight reduction usually comes with a rigidity bonus. Their biggest drawback is high maintenance cost, and Lexus is known for low cost of ownership. This might be the biggest reason Lexus is not overly commited to weight reduction. But being overweight is another issue.
CIF
  • CIF
    CIF
  • August 21, 2017
ssun30
But we were talking about a car that is very overweight even compared to much larger vehicles, which is not good.

Lightweight materials are usually stronger than plain steel so weight reduction usually comes with a rigidity bonus. Their biggest drawback is high maintenance cost, and Lexus is known for low cost of ownership. This might be the biggest reason Lexus is not overly commited to weight reduction. But being overweight is another issue.
Yes, however we don't know the full scientific specs of all the competitors compared to the LC. For example, we do know that the LC is even more rigid than the LFA, and that is an extremely rigid car. How does that compare to competitors? What about door thicknesses, or body thicknesses, and other such parameters versus the competitors? We just don't know. Also in traditional Toyota/Lexus fashion, some mechanical parts could be overengineered for reliability/quality/durability vs the competition, thus added weight.

Also stronger is relative, and a very broad term. Some lightweight materials have strong stiffness and have high tensile strength yes, but some drawbacks do exist. Some lightweight materials are weak in torsional rigidity. Some lightweight materials will break, snap, or crack very suddenly, vs other materials that simply bend or flex under such conditions. Vehicles experience a lot of twisting and shearing forces, not to mention huge amounts of vibration and wave forces during the lifetime of a vehicle. Some lightweight materials don't handle torsion, vibration, or wave forces very well.

So there are too many details we just don't know with the LC vs the competition regarding weight. If I had to guess though, the LC is overweight due to being overengineered for long-term quality/reliability/durability. This is even considering the LC has curious oddities and omissions like the lack of high-end power seats with large ranges of adjustability.
krew
ssun30
Despite the extensive use of light weight materials the LC is still overweight for its size, just like the RC. The LC is about the same weight as many full-size 4 door Coupes. The BMW 6 is lighter, the CLS is about the same, the Panamera and A7 are heavier but because of AWD. The AM DB11 is larger than the LC but is much lighter despite having a very heavy V12.
I think the decision to build up the curb weight at the expense of performance is intentional. There was ample opportunity to cut weight -- I would guess the weight of the interior materials alone is quite significant -- but Lexus had a very clear idea of what the LC should be.

I don't mean to give them a free pass, but I don't see the LC weight as a big problem outside of fuel economy.

Gecko
LC is way too heavy for it's size.... it should truly be a ~4,000lb vehicle, if that. I respect Lexus' focus on rigidity and safety, but the consequences for being ~400lbs overweight are very real.
: unamused:
zeusus
ssun30
Weight reduction is the most effective way to increase MPG: losing 5% basically means 5% better MPG. Believe it or not, a 5% increase in MPG is huge in automotive engineering. Being overweight is also counterproductive to Lexus' attempt to make "sporty vehicles". We can only hope the fact that LC is overweight means a convertible is coming, otherwise it's just unnecessary over-engineering.
Lexus really did not have to build high powered pistons into the hood to lift it up when a pedestrian is hit but they did it anyways.

Let's not pretend that Toyota has no idea how to cut weight
ssun30
Despite the extensive use of light weight materials the LC is still overweight for its size, just like the RC. The LC is about the same weight as many full-size 4 door Coupes. The BMW 6 is lighter, the CLS is about the same, the Panamera and A7 are heavier but because of AWD. The AM DB11 is larger than the LC but is much lighter despite having a very heavy V12.
Lexus really did not have to build high powered pistons under the hood to lift it up when a pedestrian is hit but they did it anyways.

There is no question Lexus knows how to cut weight and where to cut it. Relative application is important to consider and MPG numbers on the LC have been pretty impressive thus far.

Z