The $25k car is going extinct?

I didn't limit the original discussion to just an ICE motor versus an entire hybrid power train, I explicitly stated, "Depending on the _drive trains_ being compared, the hybrid _drivetrain_...". In the end people don't give a shit about if the motor is reliable, they care about if the car is reliable. The car, which includes a transmission and a heck of a lot more stuff in it. In the end the reliability of the drivetrain is more important, as that includes the reliability of the ICE and all the other stuff needed to make the car go.

If you want to focus on just the ICE part, then sure mechanically the ICE motor in a hybrid drivetrain will be similarly designed to an ICE-only drivetrain. But an ICE car is more than just an ICE motor. And to have that ICE motor actually be useful, it needs to be paired with other components. As you've aptly stated, the reliability of the system overall is extremely related to the reliability of all the components. Namely, having more complicated and less reliable components anywhere in the system makes the whole system less reliable. Having to have an incredibly complicated transmission with tons of friction points and sliding parts and fluid channels relying on specific viscosities of oil is massively more complicated mechanically than a few fixed-ratio planetary gearsets.

But guess what, even if you ignore the rest of the hybrid drive train and focus on just comparing the ICE motors, the ICE in a hybrid will probably outlive the ICE on a similar ICE-only car experiencing a similar usage pattern. The ICE in the hybrid with an e-CVT or similar will pretty much only exclusively operate in its most efficient and lowest stress ranges, while that pure-ICE vehicle needs that gas motor to work in every condition even if it is high stress.

> there needs to be some sort of discussion about why you think the ICE is more reliable

I don't think the ICE is more reliable than the hybrid. I've been arguing the opposite. The gas motor may be similarly reliable in a full ICE, but a lot of the other stuff around it becomes less reliable.

Even then thinking about things like water pumps and AC compressors and what not, a lot of that gets to be more reliable working with their own extremely reliable DC motors going exactly the speed they want to go at instead of having to be tied to engine RPMs and belts and clutches and what not wherever they want to be instead of needing to be in the path of the belt. You don't have a wimpy barely sized alternator, you have a much more reliable AC motor/generator along with an inverter and well-sized battery supplying plenty of electrical power to the system which then has a much more stable voltage for your 12V system. You don't have to put nearly as much CCA load on your 12V battery, you won't run it down as much, it stays in its optimal voltage more often, etc.

>having more complicated and less reliable components anywhere in the system makes the whole system less reliable.

This is my entire point, because the hybrid has many of the same components. Yet you get focused on individual components like transmissions instead of elaborating on the system reliability. I’ll concede that the hybrid ICE may be more reliable (that’s what I meant by asking you to provide details why the ICE is more reliable). But my point is that a more complicated system in series requires all components to be substantially more reliable to have an overall equivalent system reliability.

Consider the life of a traditional ICE engine is about the same as the batteries of a hybrid. Even if the hybrid ICE has a life 30% longer, it doesn’t make the overall system last longer. For round numbers, say the traditional ICE and hybrid batteries have a 200k mile median life (50% reliability).

That means the combined (series) R(hybrid ICE) * R(planetary gears) * R(hybrid electric motors) has to be greater than R(traditional transmission). Maybe that’s the case, and I’m asking for details and specifics.

Now obviously, it’s more complicated because there are other failure modes in each system and cost differentials as well. From the get-go, you seemed focused on individual component reliability. But unless you’re talking specifics about the system reliability you’re tilting at windmills.

So we both agree, a hybrid and a full-ICE will have many of the same components overall. They both need a battery. They both need some kind of transmission. They both need some kind of inverter. They will both have some kind of electric motor in them. In terms of actual number of components, the hybrid and the ICE are actually pretty similar.

But then we both agree, some of those components in the pure ICE are far more mechanically complicated. Higher mechanical complexity, more moving parts, etc generally means less reliability, agree? And one part of that system being radically less reliable makes the whole system less reliable, correct?

> That means the combined (series) R(hybrid ICE) * R(planetary gears) * R(hybrid electric motors) has to be greater than R(traditional transmission).

No, your math would that for the pure ICE would be R(gas ICE) * R(traditional transmission). Your ICE car isn't going to go very far without a motor to spin the transmission. And that traditional transmission is far less reliable than the fixed planetary gears. Comparatively, electric motors are extremely reliable, and chances are your hybrid gas motor will be more reliable for the same kind of required output. So, R(hybrid ICE) > R(gas ICE).

So yes, generally speaking R(hybrid ICE) * R(planetary gears) * R(hybrid electric motors) > R(gas ICE) * R(traditional transmission). Largely because that R(traditional transmission) is so absolutely terrible in comparison to R(planetary gears) * R(hybrid electric motor). Which is why I'm talking about the transmissions so much, and yet you're continuing to ignore it.

No, that was already baked in. I purposefully linked the R(gas ICE) = R(hybrid batteries). Note they were both dropped out of their respective calculation. Just like a hybrid isn’t going to go very far without batteries, but you left that reliability out of your hybrid equation. It seems you’re more interested in arguing that reading posts in good faith, so I don’t think it’s productive to continue the discussion.

> The math is clear: in series, the system reliability cannot be greater than any single part.

We both agree with this statement. The system reliability cannot be greater than any single part. In a traditional ICE, there are multiple systems which are radically less reliable than a hybrid with an e-CVT, while generally untrue of the reverse. So, with "the system reliability cannot be greater than any single part", and we can see there are parts of one system that are less reliable, which system is then logically the less reliable one? Not looking at cost at the moment, just reliability.

That is purely talking about e-CVTs and reliability of specific designs, and not necessarily reliability of all hybrids. In the end, the reliability of "a hybrid" can vary wildly. Is it a pure series hybrid we're talking about? A series-parallel e-CVT? A different kind of series-parallel? A parallel? A parallel hybrid is an example of a hybrid that probably does have worse reliability overall, as you still have all the complexity of a traditional ICE but then adding additional systems adding further complication. You're not trading away the complexity of the traditional ICE in this setup, just adding to it. All different reliability metrics on just the basic design concepts, not even then thinking about differences in reliability in manufacturing and what not across different car makers. Some car manufacturers tend to have more mistakes in actually producing things, and a good design might not actually hit planned reliability if they're not actually making the things right.

On top of that, when comparing TCO you'll see differences based on production volumes of that car. A hybrid that was only a compliance car trim level sold in only California in low volumes for a couple of model years with a bespoke battery is probably stupid expensive ($3000+) for a replacement battery after a decade. A hybrid that was mass market with many hundreds of thousands produced with long generations will have tons of used/remanufactured/aftermarket batteries on the market and might only cost $800. A lot of hybrids from the past tend to fall into the first category and not the second and were made as parallel drivetrains with notable exceptions being things like the Prius which routinely is listed as one of the lowest TCO cars out there.

Just asking for a TCO comparison of "a hybrid" compared to "a traditional ICE" is massively oversimplifying and misunderstanding the complexity of that question. Theoretically, one couldn't even say "what is the TCO of a traditional ICE vehicle?" Are we talking an F-250 Superduty or a Kia Rio or a Ferrari F40? Ignoring purchase price, each of these have radically different operating costs per mile. Which vehicle are we talking about?

This is why my original comment started off with "Depending on the drive trains being compared..." I'm not saying every hybrid will always be more reliable than every traditional ICE. It depends on which cars you're comparing.