Toyota has two hybrid system:
- the Synergy drive, like the one originally developed for Prius and currently used in most Toyota hybrid vehicles except the new Tundra and Sequoia. The Synergy drive uses two electric motors (one being actually motor-generator) and a ICE engine interconnected through a single planetary gearset. It's called eCVT becuase it behaves like a CVT (no gear shifting), but relies on the combination of the relative rotation speed of the three motors to deliver the right speed and torque to the wheels. The design is optimized for fuel economy, but at some expense of performance (acceleration and towing capacity). Another advantage of the Synergy eCVT is outstanding reliability and longevity thanks to its simplicity - there are very few moving parts, no solenoid valves, clutches, brakes, etc. like in an automatic transmission. The Synergy eCVT is the simplest gearbox you can have, even simpler than a manual transmission, and about as complicated as a typical differential.
- The hybrid system originally develop for some Lexus vehicle, and currently used in the new Tundra and Sequoia. It is basically a conventional drive system (ICE coupled to an automatic transmission), with an electric motor-generator integrated into the ICE flywheel. The main objective of this system is to deliver superior torque performance compared to the ICE only, with some improvement in fuel economy. This is why the hybrid Tundra has significantly better towing capacity of the non-hybrid version. It allows Toyota to use a smaller ICE engine with less power, while still delivering V8 performance when needed (measured in seconds or minutes). This is basically the same hybrid arrangement that most other manufacturers have been using.
Similarly to the Tundra and Sequoia, the objective of the hybrid Tacoma / 4Runner is not (much) better fuel economy, but more power / torque / towing capacity from a small ICE engine. Assuming that the new Tacoma and 4Runner will come with a 4-cyl turbo (the same ~270 hp engine as the 2023 Highlander), the hybrid will offer more power, torque and towing capacity that the ICE-only version. I suspect that the Tacoma / 4Runner 4-cyl turbo will be actually de-rated compared to the Highlander engine to improve longevity under heavier load, so I would expect 250-260 hp range for the ICE version, with modest towing capacity. The hybrid will offer ~300 hp, with better acceleration and significantly better towing (I would expect ~7k lb from the Tacoma and ~6k lb from the 4Runner), while still offering slightly better fuel economy that the "basic" powertrain. 15-20% more horsepower with 2-4 mpg better mileage is a pretty good deal.
