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I thought hybrid powertrains are simpler and more reliable in long run, so prius should be #1.

connicpu 3y ago
Definitely not, at least in systems where both the engine and motor-generator mechanically connect. You only reduce complexity when it's basically just an EV where the ICE can recharge the battery, such as the Chevy Volt or Mazda's new rotary engine vehicle.
- starkparker 3y ago
  Oddly enough, then: > There are interesting insights with the reliability of electrified models this year. Overall, hybrids have 26 percent fewer problems than cars powered by internal combustion engines (ICE). Some standouts include the Lexus UX and NX Hybrid and the Toyota Camry Hybrid, Highlander Hybrid, and RAV4 Hybrid. > Plug-in hybrid electric vehicles (PHEVs) are more of a mixed bag. As a category, they have 146 percent more problems than ICE vehicles. Several PHEVs are even less reliable than their conventional counterparts, such as the below-average Audi Q5 and Chrysler Pacifica. The latter has the lowest score in our survey, at 14. > Electric cars and electric SUVs don’t fare much better, with average reliability scores of 44 and 43, respectively. At the bottom of our vehicle-type rankings are electric pickup trucks, with an average score of 30.
  - morepork 3y ago
    I think the data is a bit skewed as Lexus/Toyota are the most reliable, and make many hybrid models. The question should be, for a particular make, are hybrids more reliable than ICEs?
jancsika 3y ago
From what I've heard the hybrid powertrains are way more complex and prone to extra problems on top of ICE problems. But it's a testament to Toyota's engineering that the Prius makes it seem that this isn't the case. In any case, on the much higher bar of running a car into the ground I think the Prius would get priced out on repairs for the last 20% of the run time. You've got both the regular battery and the hybrid battery, the regenerative braking system, and probably a lot more little dingles and dangles that would cause arguments with a spouse if you dug your heels in and kept paying for them just to run the car all the way to the finish line. With the Corolla you just might just have to decide when you've had enough of driving the damned thing.
- zik 3y ago
  The Prius powertrain is the most complex one I've seen in any vehicle. It's amazing that they can make that thing reliable.
  - VectorLock 3y ago
    Can a Prius keep going if one of its ICE or EV motors dies? Then its not complexity, its redundancy!
    - Gareth321 3y ago
      Depends what, but mostly yes. If the battery fails then the engine is used permanently. If the engine fails then the battery can be used for its limited range.
    - bestham 3y ago
      No, the 12V battery, the hybrid battery and the combustion engine all need to work for the vehicle to function.
      - red369 3y ago
        I also think this is correct. Apart from the fact that any reasonably modern cars will usually go into limp-home modes, or even stop driving, if errors are detected, I seem to remember something about an electric drive motor needing to spin backwards when driving using the combustion engine. That feels wrong as I write it, but I remember it being something fundamental to the planetary "Power Split Device".
  - willis936 3y ago
    The extra complexity spreads out the load. All of the things that often fail in an engine are less likely to when the engine only operates for a limited duty cycle, for extended durations, and for a fixed optimal load. You have the more robust motor system smooth over all of the transients. So while there are more single point failures the system might be overall more reliable. If simplicity was the only way to make something reliable we would have rickshaws rather than cars.
bastawhiz 3y ago
I'm genuinely curious how that would be true. Doesn't a hybrid have ~all of the parts of an ICE vehicle and ~all of the parts of an EV? Wouldn't that mean it can fail in far more ways?
- riku_iki 3y ago
  I am not expert at all, but my belief before this discussion was that hybrid is: - ICE, which charges battery in stable cycle - E-motor do all torque So, you don't need transmission, and ICE has way less stress, plus regenerative breaks puts way less mechanical stress on the system
  - dublinben 3y ago
    What you’re describing would be an EV with a range extender, like the BMW i3. Hybrid vehicles have a transmission to drive the wheels from both ICE and electric.
  - dwaite 3y ago
    There are 3-4 types of hybrids: 1. Series, where it is fuel -> engine -> battery -> e-motor -> wheels , with regenerative breaking as a second power source to the batteries. These are range-extended vehicles, where a small generator allows both for more range than the small batteries could supply, and the ability to run without electric charging. 2. Parallel, where both systems are driving the wheels through a clutch system. Both systems would be expected to operate at the same rate if both are engaged. This is a motor-assist system, and the majority of road power is supplied by the gasoline engine. 3. Series/Parallel (or Split) where the two systems are mixed using a planetary gear system. Among other things, this allows for gasoline motors to be optimized for efficiency with a specific set of operating conditions, knowing the electric motor can smooth out operation. 4. Plug ins, very similar to series/parallel but where the wheels are now being driven primarily by the electric motor. The e-motor is more powerful and there is significantly more battery, which now can be charged independently. The batteries are still far below a full EV, having only 5-10% of the range available as a "full EV" mode. All of these systems effectively have a single point of interaction between the gasoline and electric systems - for series it is the batteries, for parallel it is the clutch, for split systems and plug-ins it is the planetary gear system. The difference I suppose is that the series system has a wire connection to the gasoline engine rather than a physical drive connection, so conceptually it seems easier to swap out. I heard that the Chevy Volt as an example was originally planned to be a series system, but the electric motor simply wasn't capable of providing the highway performance they wanted - so it ultimately shipped as a series-parallel system.

Definitely not, at least in systems where both the engine and motor-generator mechanically connect. You only reduce complexity when it's basically just an EV where the ICE can recharge the battery, such as the Chevy Volt or Mazda's new rotary engine vehicle.

starkparker 3y ago
Oddly enough, then: > There are interesting insights with the reliability of electrified models this year. Overall, hybrids have 26 percent fewer problems than cars powered by internal combustion engines (ICE). Some standouts include the Lexus UX and NX Hybrid and the Toyota Camry Hybrid, Highlander Hybrid, and RAV4 Hybrid. > Plug-in hybrid electric vehicles (PHEVs) are more of a mixed bag. As a category, they have 146 percent more problems than ICE vehicles. Several PHEVs are even less reliable than their conventional counterparts, such as the below-average Audi Q5 and Chrysler Pacifica. The latter has the lowest score in our survey, at 14. > Electric cars and electric SUVs don’t fare much better, with average reliability scores of 44 and 43, respectively. At the bottom of our vehicle-type rankings are electric pickup trucks, with an average score of 30.
- morepork 3y ago
  I think the data is a bit skewed as Lexus/Toyota are the most reliable, and make many hybrid models. The question should be, for a particular make, are hybrids more reliable than ICEs?

jancsika 3y ago

From what I've heard the hybrid powertrains are way more complex and prone to extra problems on top of ICE problems. But it's a testament to Toyota's engineering that the Prius makes it seem that this isn't the case. In any case, on the much higher bar of running a car into the ground I think the Prius would get priced out on repairs for the last 20% of the run time. You've got both the regular battery and the hybrid battery, the regenerative braking system, and probably a lot more little dingles and dangles that would cause arguments with a spouse if you dug your heels in and kept paying for them just to run the car all the way to the finish line. With the Corolla you just might just have to decide when you've had enough of driving the damned thing.

zik 3y ago
The Prius powertrain is the most complex one I've seen in any vehicle. It's amazing that they can make that thing reliable.
- VectorLock 3y ago
  Can a Prius keep going if one of its ICE or EV motors dies? Then its not complexity, its redundancy!
  - Gareth321 3y ago
    Depends what, but mostly yes. If the battery fails then the engine is used permanently. If the engine fails then the battery can be used for its limited range.
  - bestham 3y ago
    No, the 12V battery, the hybrid battery and the combustion engine all need to work for the vehicle to function.
    - red369 3y ago
      I also think this is correct. Apart from the fact that any reasonably modern cars will usually go into limp-home modes, or even stop driving, if errors are detected, I seem to remember something about an electric drive motor needing to spin backwards when driving using the combustion engine. That feels wrong as I write it, but I remember it being something fundamental to the planetary "Power Split Device".
- willis936 3y ago
  The extra complexity spreads out the load. All of the things that often fail in an engine are less likely to when the engine only operates for a limited duty cycle, for extended durations, and for a fixed optimal load. You have the more robust motor system smooth over all of the transients. So while there are more single point failures the system might be overall more reliable. If simplicity was the only way to make something reliable we would have rickshaws rather than cars.

bastawhiz 3y ago

I'm genuinely curious how that would be true. Doesn't a hybrid have ~all of the parts of an ICE vehicle and ~all of the parts of an EV? Wouldn't that mean it can fail in far more ways?

riku_iki 3y ago
I am not expert at all, but my belief before this discussion was that hybrid is: - ICE, which charges battery in stable cycle - E-motor do all torque So, you don't need transmission, and ICE has way less stress, plus regenerative breaks puts way less mechanical stress on the system
- dublinben 3y ago
  What you’re describing would be an EV with a range extender, like the BMW i3. Hybrid vehicles have a transmission to drive the wheels from both ICE and electric.
- dwaite 3y ago
  There are 3-4 types of hybrids: 1. Series, where it is fuel -> engine -> battery -> e-motor -> wheels , with regenerative breaking as a second power source to the batteries. These are range-extended vehicles, where a small generator allows both for more range than the small batteries could supply, and the ability to run without electric charging. 2. Parallel, where both systems are driving the wheels through a clutch system. Both systems would be expected to operate at the same rate if both are engaged. This is a motor-assist system, and the majority of road power is supplied by the gasoline engine. 3. Series/Parallel (or Split) where the two systems are mixed using a planetary gear system. Among other things, this allows for gasoline motors to be optimized for efficiency with a specific set of operating conditions, knowing the electric motor can smooth out operation. 4. Plug ins, very similar to series/parallel but where the wheels are now being driven primarily by the electric motor. The e-motor is more powerful and there is significantly more battery, which now can be charged independently. The batteries are still far below a full EV, having only 5-10% of the range available as a "full EV" mode. All of these systems effectively have a single point of interaction between the gasoline and electric systems - for series it is the batteries, for parallel it is the clutch, for split systems and plug-ins it is the planetary gear system. The difference I suppose is that the series system has a wire connection to the gasoline engine rather than a physical drive connection, so conceptually it seems easier to swap out. I heard that the Chevy Volt as an example was originally planned to be a series system, but the electric motor simply wasn't capable of providing the highway performance they wanted - so it ultimately shipped as a series-parallel system.