Hybrid Power Split Device. eCVT transmission.
Why Hacker News recommends it
HN people link it in hybrid versus EV debates as a clear view of how simple the hybrid drivetrain really is.
What it is
A short animated explanation of the power split device in Toyota-style hybrids, a planetary gearset that works as an eCVT. It shows how engine and motor power are combined.
Recommended by 1 HN commenters across 1 different months, 2023 to 2024.
What Hacker News said
Recommends CRConrad · 2024-12 · on “First Geared CVT [video]”
More YouTube videos about the eCVT... 1) Better -- much simpler, and above all shorter -- video explanation of the Toyota system: [this video] . 2) Another, a little longer, but very pedagogical and beautifully animated explanation: [LINK] . Eight years old, but apparently the "power split device" worked the same even then. Bonus -- short conversation in the comments, arriving at the same conclusion I did above: @TimpBizkit 3 weeks ago I thought the prius had a cvt 1 reply @aspecreviews 3 weeks ago It doesn't. The "CVT" is electrically simulated. Heh, yeah. 3) Titled something about "Launch Gear", but actually on the whole CVT thing (from a channel I semi-regularly watch): [LINK] . 4) A good basi
Cites somerandomqaguy · 2023-07 · on “Toyota Is Right: We Need More Hybrid Cars and Fewer EVs. Here’s Why”
Toyota's eCVT? Not at all. The gas engine can drive the front wheels directly. [this video] Conceptual explanation of the system. [LINK] Weber Auto giving an extensive hands on explanation.
Cites dragontamer · 2024-03 · on “Toyota was right about hybrid cars”
All the "complexity" of a hybrid (or at least... a Prius) is approximately 15 gears that replace the alternator/starter/transmission. The Toyota Power-split device is a planetary-gearset connecting 2x electric motors/generators with 1x ICE engine. But a regular ICE car needs 2x electric motor/generators *anyway*. #1 is called the starter (turns Lead-Acid battery pack into cranking force to start the engine), and #2 is called the alternator (turns engine RPMs into electricity to charge the battery pack). Then you need a gear-shifter to have the ICE car handle a variety of different speeds. Change #1 and #2 to be bigger, stronger. Then make the effective-gear shifting a function of the relatio
Cites dragontamer · 2024-03 · on “Mazda’s rotary engine in the age of the electric car”
> but an appropriate gear ratio should handle that. See Prius's "Powersplit Device". I'd describe the Powersplit device to be a combination of generator/alternator, starter/electric motor, reversed-differential (2x power inputs -> 1x driveshaft), and effective gear-ratio. All in one planetary gearset. EV motor2 determines the speed of the car. The ICE motor can spin at any speed that the computer determines to be useful. If EV Motor2 is 0-rpm, then the ICE is 100% in generator mode (2000rpm but the car isn't moving: all the energy goes to charging the battery). If the EV motor is at 10mph but ICE is off (0-rpm), then its 100% electric drive mode. And any combination in-between is possible. E
Cites dragontamer · 2024-04 · on “Tesla releases Q1 2024 deliveries: disastrous results”
> You've got everything that can fail in a fairly high tech ICE drivetrain, plus everything that can fail in an EV drivetrain You should seriously look up the drivetrain of hybrids. The planetary gearset is a single set of gears that functions as the alternator/generator, the starter/EV motor, the transmission, and the engine driveshaft. Its not "different" or "new" components. Its a singular design that accomplishes what 3x different parts of the car used to do seperately. There's a reason why Toyota Hybrids are $23k, its a lot cheaper and more efficient to do it this way. [this video] You needed the starter anyway. When its beefed up to a full-size EV motor that can drive the car, its more powe