Cybertruck Engineering Innovations

[Mach-Lee]

These may not get much attention from the general public, but Cybertruck does have some significant engineering achievements that will hopefully trickle down to other vehicles:

• Fully Steer-by-Wire - The steering wheel is no longer connected to the wheels, first vehicle to market like this (Lexus is also working on this, but has't been released). It is like a force feedback joystick that causes the front wheels to move. The force feedback unit provides return-to-center torque and force feedback based on detected steering load. The lack of mechanical connection also allows a variable steering ratio to be used (based on speed), and the total steering rotation is less than one turn (vs. 3-4 turns for a regular car). This means hand-over-hand steering is no longer necessary since half a turn is full left or right angle. You can turn the steering wheel when the truck is off and the wheels don't move. The required safety redundancy (that allows complete removal of a mechanical connection) is provided by two separate electric motors on the same steering column, with triple redundant sensors. This is the steering rack, I've never seen one with two motors before:

• Fully 48V LV Electrical System - The low voltage system has completely switched from 12V to 48V. There are no 12V components in the vehicle (no 12V ports either, 120V and USB-C only). This is the first vehicle in the world to fully switch to 48V, the traditional automakers have been talking about this since the 1980's but haven't been able to make it happen yet. Hopefully this is a kick in the pants. Higher voltage means the wires can be made smaller, and is also more efficient. All three steering motors draw a combined 5 horsepower at full power, which would completely overload a 12V system (300 amps). With 48V, high output steering devices are possible. I assume there is a small 48V lithium battery powering the 48V system when the truck is off.
• Distributed CAN bus architecture - Rather than having multiple CAN networks, there is a single gigabit ethernet network that connects everything in the car. This means most wire runs are extremely short and only involve a pair of power and CAN bus wires, eliminating a lot of wiring. This is in contrast to the traditional method where a body control module located in one spot has dozens of wires that run to all parts of the vehicle from it. No more thick harnesses. This is what Jim Farley was talking about when eliminating wiring waste from vehicles. Like other current Tesla models, the Cybertruck also completely eliminates the need for fuses through intelligent power control, which is still unique in the industry.
• 400V/800V switchable pack architecture - The 123 kWh battery pack normally runs in 800V mode for driving, which makes it incompatible with existing Superchargers that only go to 450V. So Tesla invented a switch that splits the pack in two, making two 400V halves in parallel while charging. This works opposite of the Hummer EV which is normally 400V and switches to 800V for charging. It's unknown whether the Cybertruck will allow 800V CCS charging, if so it could break a charging speed record. Here's the switch:

• Exoskeleton - In addition to the battery pack, the exterior body panels are also structural. This means there is no internal structure or crash bars inside the doors, and it still passes side impact tests with flying colors. The steel is extremely strong, durable, and actually bulletproof.
• Quickest pickup truck ever - The Cybertruck has beat the Rivian R1T is is now the quickest pickup truck ever, with a 0-60 of 2.6 sec and 11.0 sec @ 119 mph quarter mile. This performance is available without special battery preconditioning, and apparently unchanged with repeated runs all the down to 33% battery, which is unheard of.
• Bidirectional charging - Tesla calls this Powershare, the on-board plugs can output 9.6 kW (same as F-150 Lightning), and will also support up to 11.5 kW of power output for V2H to power your home. This will require a Powerwall. Similar to F-150 Lightning Intelligent Backup but with higher total output and less integration equipment required (provided you have a Powerwall). It's unknown whether Tesla will allow the Cybertruck to operate in V2G mode with Autobidder software and sell power back to the grid when it's profitable. If this were possible you could make hundreds of dollars per month, since the Cybertruck has the capacity of 9x Powerwalls.
• Largest Windshield and Wiper - At 4 feet long, the blade is the longest ever produced. It is a single blade. The huge windshield is also the largest ever mass produced. The wiper actually changes angle slightly while driving to improve the aerodynamics at different speeds (a form of active aero). When the wiper is on, it parks at the bottom of the windshield instead.

I don't like the Cybertruck, but I do hope some of these technologies can trickle down to other EVs, especially the 48V electrical system and steer-by-wire. These should have been invented already and present on cars 10+ years ago.

PART 2 UPDATE - Munro just released a video interviewing the Cybetruck engineers, and there's even more prodigious engineering on display here. I know some Munro videos are hit or miss, but this one is must-see for engineering buffs.



More details revealed:

• 48V System - You can actually jump start the 48V Cybertruck with a 12V battery, thanks to a built in boost converter that ups the voltage from 12V to 48V!
• EtherLoop - There's a single gigabit ethernet network that is arranged in a loop, through which all vehicle communications pass through. If the loop is cut anywhere, then the signals will travel the other way around the loop to reach their endpoints. Audio to each speaker also flows around on the same network as vehicle communication. 368 total endpoints in the system. 68% reduction in the number of cross car wires with this setup. Cybertruck also uses active noise cancellation (to cancel out road noise) microphone signals also flow over the EtherLoop network for processing.
• HFS "Hard Freakin' Stainless - Special cold rolled steel alloy designed to be extra durable and corrosion resistant. Tesla has a special process called "Air Bending" to form the panel that uses a compressed air cushion to prevent cosmetic defects.
• Largest door ring - The door ring (door openings) is made of a single inner and outer piece (boron steel) stamped and spot welded together with minimal finishing (power coating).
• CFD optimized castings - The flow of metal into the single large front and rear castings is optimized with computational fluid dynamics to reduce the tonnage of the press required. This means they can use their existing Model Y presses for the front casting. The curved strengthening ribs are designed with casting flow in mind rather than being purely structural like contemporary diamond strengthening. In this sense the CFD ribs are dual purpose (serves as a casting flow channel and for structural strengthening). Very smart idea. Form meets function.

• Motor platform commonality - All the motors in all the configurations (RWD, dual, tri motor) of the cybertruck share the same parts. They're all mix and match confutations of one permanent magnet (PM) rotor, one inductive magnet (IM) rotor, one inverter, one gear reduction. Unlike the Mach-E which has completely different front and rear motors, inverters, gear reductions, etc. All Cybertrucks have on PM motor, and additional motors are inductive to reduce idle torque losses for efficiency.

• Body controller - Mounted to the firewall and has harness connections on both sides (inside and outside). Eliminates the need for wires to pass through the firewall with grommets. Ethernet controlled is integrated on this board, as well as the motor controls for wipers, windows, etc and audio amplifiers all on the same board. The connectors are integrated into the module cover so there isn't a separate part.

• New Power Conversion Board - It is a 11.5 kW bidirectional charger and 3 kW 48V DC/DC converter all in one. Personally I was blow away at how small this is. 100% smaller than before. All the components are surface mount including the magnetics! You can power your house with the full 11.5 kW through the charge port. 110 amps (25 kW?!) of inrush capability, which can start your large home A/C compressor! Or charge another EV.

• 400V/800V Series/Parallel switch - I mentioned this above, but they have additional diagrams that shows how it works. One thing they added is that all the high voltage accessory components like the A/C compressor will also run on 400V when the pack is in that mode during charging.

• Steer by wire rack - Dual motors sized to handle 60% of the peak load. Rear rack motor is the same design as well for commonality. Designed for sensor diversity as well, one side has an angle sensor, the other side a position sensor so there are two different redundant sensing methods. Both front and rear rack designed by the same person. 340º lock-to-lock steering angle.
• Independent compression and rebound damping control - The suspension struts have independent compression and rebound valves that can be adjusted every 10 ms. Sort of like MagneRide but way beefier for off-road use. Can precisely control ride, body dynamics, and roll characteristics.

• 4680 Dry Cell Pack - 9% higher energy density compared to Model Y, dry cell technology for more efficient and cheaper manufacturing.

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[GreaseMonkey]

Love it or hate it, this is what’s been unique about Tesla. They’ve been willing to start from a blank sheet and design things without being constrained with the past. We will all benefit from their innovations even if we never buy one of their vehicles.

 

[Unobtanium]

Wow. That is legit advancement. Im not really into Tesla, but the innovation here can't be denied.

 

[Jimrpa]

I thought EPAS was “steer by wire” with no physical connections between the steering wheel and the front wheels? Basically, the steering wheel is a fancy potentiometer or something?

 

[Gimme_my_MME]

EPAS

Electronic Power Assist Steering, still mechanical based. But Ford does have a variable system where you get the benefit of steer by wire with the failsafe of the mechanical system

 

[nvabill]

Thanks for the info, this is pretty amazing stuff for us car guy lay people!

 

[Ghost Ryder]

Is this correct?

"Fully Steer-by-Wire - The steering wheel is no longer connected to the wheels, first vehicle to market like this"

"Steer-by-wire without the use of a steering column was first offered in a production car with the Nissan Infiniti Q50 in 2013."

https://en.wikipedia.org/wiki/Steer-by-wire

True, but the Infiniti had a mechanical backup where the wheel could be directly connected to the rack. Whereas none exist on the CT.

 

[Ghost Ryder]

A lot of these advancements will trickle down to their other models.

 

[LincolnLuvr]

Great summary, OP!

Will we see a 48V system in the Mach-E Gen 2?

 

[Mach-Lee]

The 48V electrical system is a great innovation for all automotive applications EV or ICEV. But I'm a bit queasy on the steer-by-wire system. Regardless of the triple sensor redundancy and double redundancy of the electric motors, any mechanical part can fail, electromechanical components even more so. I didn't see where there is redundancy in the force feedback control box, but I guess there is. But I'd like to understand what happens if there is a total loss of 48V power. I'd hope there are some large capacitors that power the system for a few minutes to allow for a controlled safe stop. What is the fail safe? Having a steering column near-fail on my truck last year (due to rust), it is not a good feeling to lose steering control (or nearly losing control).

It's nice the influencers talk about airplanes fly-by-wire tech, but airplanes have a lot of room to maneuver and there are no obstacles in the sky sitting there to hit. And commercial aircraft have redundant separate systems (electrical and hydraulic) to still control 3-dimensional flight. This is much different than redundant sensors or motors using the same mechanical apparatus to control 2-dimensional steering in traffic at speed. There is just no room for steering failure in ground-based Transporation vehicles. Tesla is known for beta testing systems (and software) on an unsuspecting public. It would be interesting to know the DOT/SAE approval of Tesla's steer-by-wire system.

The side-crash performance is very impressive.

My guess is they might have dual redundant 48V systems in the car (dual DC/DC converters). Probably one to each motor. So if one 48V system had a fault, the other would remain. Then there’s also the 48V battery, which should be enough to pull over. I would assume they’ve thought of many possible failure scenarios. With a distributed electrical system, it might be almost impossible to have complete electrical failure. Unlike most other cars which still use a single point electrical distribution box.

 

[Ghost Ryder]

I think it has already been stated the Cyber Truck is drive-by-wire with no backup mechanical linkage. As I said earlier, Tesla needs to provide detail as to what the fail-safe is. I doubt any of the Apple Geniuses at Tesla stores will be able to convey what the fail-safe is.

If they laid out the engineering detail of their electrical system, would most people understand? How much detail do you want them to go into.

Mach-Lee listed some of the components of the redundancy system that they have implemented. Will that be enough.?

 

[GreaseMonkey]

If they laid out the engineering detail of their electrical system, would most people understand? How much detail do you want them to go into.

Mach-Lee listed some of the components of the redundancy system that they have implemented. Will that be enough.?

Enough for planes!

 

[Mach-Lee]

Without knowing the exact architecture of the low-voltage system it is a good guess, but I thought the low voltage system feeds off the LVB (48V) and my thought was what happens if for some rare reason the LVB just fails all together and passes zero current. Again, I'm just guessing on the architecture.

If the LVB fails while driving then the DC/DC converter would take the load. Current doesn’t need to pass through the battery, it’s in parallel.

It’s entirely possible Tesla designed it so you could switch off or destroy half the electrical system and the truck would still work. It may also be able to reroute power an alternative way à la Star Trek. Totally possible if they designed extra redundancy into the electrical system.

A lot of people will be interested in the 48V system and steer-by-wire when Munro does his teardown. We’ll have to wait for more details on the inner workings.

 

[Logal727]

I hate they made it look like crap

 

[Cosmacelf]

I assume there is a small 48V lithium battery powering the 48V system when the truck is off.

Yes indeed. All Teslas now use lithium-ion low voltage batteries to power all LV subsystems, and in this case, it would be a 48V version.

Like other current Tesla models, the Cybertruck also completely eliminates the need for fuses through intelligent power control, which is still unique in the industry.

Right. Very few people know about this. Teslas all have microprocessor monitoring of all loads and can shut off power quicker than a fuse, but also reset power if the fault is fixed. This also allows for tighter tolerances since the control logic can allow higher currents for motor startups, but have tighter current limits for steady state operation. It's probably a wash cost wise once the engineering was done.

It's unknown whether the Cybertruck will allow 800V CCS charging, if so it could break a charging speed record.

Tesla V4 Superchargers (of which there are very few in existence), supposedly will be able to deliver 800V, so presumably that would allow 350kW charging at 800V.

For CCS, Teslas would need to use their CCS adapter, and that is only rated to 500V, so unless Tesla comes out with an updated adapter, Cybertrucks would be limited to 400V and 250kW charging at CCS stations.

It's unknown whether Tesla will allow the Cybertruck to operate in V2G mode with Autobidder software and sell power back to the grid when it's profitable. If this were possible you could make hundreds of dollars per month, since the Cybertruck has the capacity of 9x Powerwalls.

Probably won't be allowed. Tesla really does want you to buy Powerwalls for that. The Powershare features is meant for household emergency power backup and as another way to offtake power from the battery on the road.

I don't like the Cybertruck, but I do hope some of these technologies can trickle down to other EVs, especially the 48V electrical system and steer-by-wire. These should have been invented already and present on cars 10+ years ago.

Absolutely. Tesla supposedly sent all OEMs and suppliers a PDF titled "How to engineer a 48V vehicle" which contains discussions about what does and doesn't work and what pitfalls Tesla ran into while designing 48V parts. Frankly, I am surprised Tesla doesn't just become a parts supplier for 48V components.

And steer by wire - regular steering systems fail! I remember once driving a cargo van and the power steering went out. OMG, it took all my strength to steer that thing to a controlled stop without hitting a lamp post. That Cybertruck system has triple redundant sensors - it's going to realize something went wrong before you do. And with a backup steering motor, you probably won't even notice a problem before the warning message pops up to take the truck into service.

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