Rivian Zonal Electrical Architecture Explained -- Popular Science

[docwhiz]

https://www.popsci.com/technology/rivian-zonal-electrical-architecture/

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[Jimflip]

Not trying to be a smart-ass, but I read this paragraph in the story and wondered if this was an oversight/error.

I think the count is off by 1 - they say 4 categories, then list 5?

"For the second generation of vehicles, four categories get their own ECUs: infotainment (1), autonomy (2), vehicle access (3), drive units (4), and its battery management system (5)."

(Bold & bold/italic inserts are mine)

 

[docwhiz]

Not trying to be a smart-ass, but I read this paragraph in the story and wondered if this was an oversight/error.

I think the count is off by 1 - they say 4 categories, then list 5?

"For the second generation of vehicles, four categories get their own ECUs: infotainment (1), autonomy (2), vehicle access (3), drive units (4), and its battery management system (5)."

(Bold & bold/italic inserts are mine)

I think they are lumping the drive units and BMS together.

 

[Jimflip]

Since posting, I've been searching online to try and find a listing of what each of the revised "7" ECUs does. (Tempted to call them "The Magnificent Seven" ?)

I found what is likely the origin of the paragraph in the PopSci article on Rivian's website <here, about 1/2 way down the page in the section "Electrical Architecture and Compute Platform">:

"While infotainment, autonomy, vehicle access, drive units and our battery management system each have their own ECU, every other vehicle function is controlled by just three ECUs."

That appears to confirm @docwhiz ?? that BMS & Drive units share an ECU.

In the PopSci article, the rewording and inclusion of the extra comma after the colon had me confused.

 

[docwhiz]

The subhead of the article:
How Rivian reduced electrical wiring by 1.6 miles and 44 pounds
The EV maker reduces software and hardware complexity with zonal electrical architecture.

This is impressive engineering which should make Rivians less expensive and more reliable.

All of it was developed in-house by Rivian’s hardware and software team, an impressive feat. Software complexity is a big deal, and Rivian is finding ways to simplify and streamline its golden goose as a software-defined automaker.

“We had 17 ECUs [in Gen 1], each dedicated to a category,” Rajagopalan says. “Other manufacturers can have between 40-150 per vehicle, depending on how they work.”

Even though Rivian was using significantly fewer pieces of hardware than their competitors, they wanted to improve the system. More ECUs means more parts overall; consequently, that leads to increased opportunities for failure.

With a new joint venture with Volkswagen in progress, Rivian will have the opportunity to build a common platform on a much larger scale. To start, VW will invest $1 billion in Rivian and invest another $4 billion over time. In turn, VW will benefit from Rivian’s software-defined vehicle expertise and maverick approach.

 

[Zoidz]

All of it was developed in-house by Rivian’s hardware and software team, an impressive feat. Software complexity is a big deal, and Rivian is finding ways to simplify and streamline its golden goose as a software-defined automaker.

We will likely never find out, but I'm curious as to how much of the hardware was designed by Rivian vs. using "off the shelf" chips and OEM subsystem boards. I'm guessing that Rivian didn't design their own silicon, but instead used ASICs (Application Specific Integrated Circuit)and SOC (System On a Chip) with their own board design and software.

One thing the article doesn't mention is that Zonal Architecture isn't a Rivian creation, it's an industry initiative going back 5+ years.

 

[docwhiz]

We will likely never find out, but I'm curious as to how much of the hardware was designed by Rivian vs. using "off the shelf" chips and OEM subsystem boards. I'm guessing that Rivian didn't design their own silicon, but instead used ASICs (Application Specific Integrated Circuit)and SOC (System On a Chip) with their own board design and software.

One thing the article doesn't mention is that Zonal Architecture isn't a Rivian creation, it's an industry initiative going back 5+ years.

Rivian seemed to have no problem integrating its software with the test Audis that VW shipped to them so I imagine that they have figured out how to integrate "industry standard" components into their software. (Unlike legacy auto, which is totally confused by all of this new software stuff since it's just too complicated)

 

[BrayBay]

The infotainment ECU alone is as powerful as a laptop and has the capabilities of a smartphone.

What...?

Interesting information, but this article could be written a little better.

 

[Joules Burn]

Interesting, but the actual Rivian wiring diagram is as elusive as the Voynich Manuscript - and the disappearance of the dash/frunk 12 volt supply.

 

[docwhiz]

What...?

Interesting information, but this article could be written a little better.

Seems clear to me.
Do you not understand the capabilities of a smartphone or laptop?

 

[docwhiz]

Interesting, but the actual Rivian wiring diagram is as elusive as the Voynich Manuscript - and the disappearance of the dash/frunk 12 volt supply.

Do you understand that the graphics in the article are not wiring diagrams but are zone diagrams?
Don't panic. (I'm sure your beloved 12v outlets will appear in the actual wiring diagram.)

 

[NY_Rob]

The subhead of the article:
How Rivian reduced electrical wiring by 1.6 miles and 44 pounds
The EV maker reduces software and hardware complexity with zonal electrical architecture.

This is impressive engineering which should make Rivians less expensive and more reliable.

“We had 17 ECUs [in Gen 1], each dedicated to a category,” Rajagopalan says. “Other manufacturers can have between 40-150 per vehicle, depending on how they work.”

Impressive? Yes, but as in most engineering decisions there is a potential downside. In the past, if one ECU/system went down it only (potentially) crippled a small part of the vehicle. Now with only 7 ECU's controlling the Gen 2 vehicles vs 17 ECU in Gen 1 vehicles, if one ECU/system goes down, it affects much more of the whole vehicle. Again, I stress the word "potentially" as each failure presents unique failure scenarios.

 

[docwhiz]

Impressive? Yes, but as in most engineering decisions there is a potential downside. In the past, if one ECU/system went down it only (potentially) crippled a small part of the vehicle. Now with only 7 ECU's controlling the Gen 2 vehicles vs 17 ECU in Gen 1 vehicles, if one ECU/system goes down, it affects much more of the whole vehicle. Again, I stress the word "potentially" as each failure presents unique failure scenarios.

I don't think it makes much difference to the owner if a small part of a larger part of the vehicle is disabled.
Also, ECU failures are rare. I haven't read many (?any) stories of ECU failures. Fewer ECUs means fewer chances of failure

 

[NY_Rob]

I don't think it makes much difference to the owner if a small part of a larger part of the vehicle is disabled.
Also, ECU failures are rare. I haven't read many (?any) stories of ECU failures.

Possibly, but with a small failure you might still be able to drive the vehicle vs a large failure rendering the vehicle non-drivable stranding you and your Rivian somewhere, possibly many miles from home.

 

[allisgoodman]

I am curious if Rivian is doing better than Tesla in terms of electrical architecture.

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