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Modern transmissions can’t be two orders of magnitude more complicated than a modern ICE. If they are then I need to get into transmission design. An automati

by mulmen 3y ago

Modern transmissions can’t be two orders of magnitude more complicated than a modern ICE. If they are then I need to get into transmission design. An automatic transmission is basically just a series of planetary gears anyway. I would expect the marginal complexity between an ICE transmission and a hybrid transmission to be within a multiple of 2, but closer to parity. They’re both extremely reliable but an EV transmission (gearbox) will be even simpler.

hnav 3y ago
The thing that mechanically totals modern crap cars (think cheap Nissans and Subarus) is often the CVT. Ford and GM have transmission problems pretty often. GP is totally right that the planetary eCVTs actually make cars way simpler. Look at Ford's (horrendous reputation with small cars) hybrids from the 2010s, lots of them running around with 300k on the clock.
- SmellTheGlove 3y ago
  > (think cheap Nissans and Subarus) You don't even need to limit it to the lower end models with Subaru. The top trim Outback and Ascent have a CVT these days. If you want an automatic transmission in your WRX, same thing - a CVT. Anyway, you're not wrong.
- mulmen 3y ago
  A CVT is even simpler than an automatic. They may be less reliable but not necessarily more complicated.
pkulak 3y ago
I dunno, maybe 100x was an exaggeration, but not by much! Take a look at this transmission from 2007. They haven't gotten simpler. Lot's of cars are sporting 10-speeds these days. https://en.wikipedia.org/wiki/Automatic_transmission#/media/File:Automatic_transmission_cut.jpg https://en.wikipedia.org/wiki/Automatic_transmission#/media/...
- mulmen 3y ago
  The number of speeds is a function of the number of planetary gearsets. They’re just connected in series. More speeds isn’t more complex, it’s only a larger part count. By the time the transmission is computer controlled and has two speeds it’s as complex as it’s going to be. Modern ICE are also extremely complex. Turbo systems, sensors, air management, heat management, the list goes on. So yeah, a modern transmission is complex but a modern ICE isn’t simple. By comparison they’re very similar in terms of complexity, the ICE possibly being even more complex.
  - serf 3y ago
    >By the time the transmission is computer controlled and has two speeds it’s as complex as it’s going to be. I don't disagree with your posts greater point, but I disagree with this. There is an endless amount of variable complexity in the engineering behind friction materials, actuation styles, the control systems within the computer control, the material selections.. the list goes on. I mean entire branches of metallurgy were more or less founded in the pursuit of finding stronger alloys for gearbox work. entire branches of metrology were developed for the sake of gearbox failure analysis -- there is a lot of complexity. It's stupid to get into a pissing contest between engines and transmissions, they're both astoundingly complex.
    - deleted 3y ago
      [deleted]
    - mulmen 3y ago
      I don’t buy that transmissions are somehow unique or even exceptional in motivating improvements in design and materials science. The ICE will benefit from the same improvements and has even more opportunities to utilize those improvements.
robocat 3y ago
Look at a workshop maintenance manual to get a rough idea. One car I had, about a third of the book was dedicated to the automatic transmission. Auto transmissions are very complex.
- mulmen 3y ago
  Yes, in a past life I rebuilt automatic transmissions so I am familiar with their complexity. Transmissions are complex but so are a lot of things. Internal combustion engines are more complex than transmissions. Pages in a shop manual are a proxy for the complexity of service, not of the component itself.

by mulmen 3y ago

hnav 3y ago

The thing that mechanically totals modern crap cars (think cheap Nissans and Subarus) is often the CVT. Ford and GM have transmission problems pretty often. GP is totally right that the planetary eCVTs actually make cars way simpler. Look at Ford's (horrendous reputation with small cars) hybrids from the 2010s, lots of them running around with 300k on the clock.

SmellTheGlove 3y ago
> (think cheap Nissans and Subarus) You don't even need to limit it to the lower end models with Subaru. The top trim Outback and Ascent have a CVT these days. If you want an automatic transmission in your WRX, same thing - a CVT. Anyway, you're not wrong.
mulmen 3y ago
A CVT is even simpler than an automatic. They may be less reliable but not necessarily more complicated.

pkulak 3y ago

I dunno, maybe 100x was an exaggeration, but not by much! Take a look at this transmission from 2007. They haven't gotten simpler. Lot's of cars are sporting 10-speeds these days. https://en.wikipedia.org/wiki/Automatic_transmission#/media/File:Automatic_transmission_cut.jpg https://en.wikipedia.org/wiki/Automatic_transmission#/media/...

mulmen 3y ago
The number of speeds is a function of the number of planetary gearsets. They’re just connected in series. More speeds isn’t more complex, it’s only a larger part count. By the time the transmission is computer controlled and has two speeds it’s as complex as it’s going to be. Modern ICE are also extremely complex. Turbo systems, sensors, air management, heat management, the list goes on. So yeah, a modern transmission is complex but a modern ICE isn’t simple. By comparison they’re very similar in terms of complexity, the ICE possibly being even more complex.
- serf 3y ago
  >By the time the transmission is computer controlled and has two speeds it’s as complex as it’s going to be. I don't disagree with your posts greater point, but I disagree with this. There is an endless amount of variable complexity in the engineering behind friction materials, actuation styles, the control systems within the computer control, the material selections.. the list goes on. I mean entire branches of metallurgy were more or less founded in the pursuit of finding stronger alloys for gearbox work. entire branches of metrology were developed for the sake of gearbox failure analysis -- there is a lot of complexity. It's stupid to get into a pissing contest between engines and transmissions, they're both astoundingly complex.
  - deleted 3y ago
    [deleted]
  - mulmen 3y ago
    I don’t buy that transmissions are somehow unique or even exceptional in motivating improvements in design and materials science. The ICE will benefit from the same improvements and has even more opportunities to utilize those improvements.

robocat 3y ago

Look at a workshop maintenance manual to get a rough idea. One car I had, about a third of the book was dedicated to the automatic transmission. Auto transmissions are very complex.

mulmen 3y ago
Yes, in a past life I rebuilt automatic transmissions so I am familiar with their complexity. Transmissions are complex but so are a lot of things. Internal combustion engines are more complex than transmissions. Pages in a shop manual are a proxy for the complexity of service, not of the component itself.