There is no connection between an E-CVT and a mechanical CVT, except for their ability to generate a potentially infinite number of gear ratios to optimize efficiency. But E-CVT and CVT has different components, Structure and design principal.
What is E-CVT transmission in hybrid: What connects to Which
- A ring gear connected to the wheels and a large electric motor (MG2).
- A planet carrier connected to the gasoline engine.
- A sun gear connected to a smaller electric motor/generator (MG1).
How the E-CVT operates
- MG1 and MG2 work together to control the speed and power delivery:
- MG2 acts as a motor to propel the car using electric power.
- MG1 acts as a generator to capture excess engine power and charge the battery.
- The resistance MG1 applies to the engine determines how much it assists the car.
Advantages And Disadvantages of E-CVT
Advantages of E-CVT
- Highly reliable due to the absence of belts and clutches that wear out.
- Improved fuel efficiency due to optimized engine operation.
- Lighter weight compared to traditional transmissions.
- Allows for seamless transitions between electric and gasoline power.
Disadvantages of E-CVT
- Some may find the driving experience less engaging compared to traditional transmissions.
E-CVT Transaxle Example with Vehicle Model
- Toyota P610: 4th generation Prius (2016-2022), C-HR 1.8L (2018-2022), Corolla Hybrid 1.8L (2019-2022), Corolla Cross (2021-) – first with motor and generator in parallel instead of in series.
- Toyota P710: 2019 & above RAV4 Hybrid, 2018 & above Camry Hybrid ,2018 & above Avalon Hybrid, 2018 & above Lexus ES300h Hybrid.
- Toyota P810: RAV4 prime Hybrid, Highlander Hybrid (2020-), Sienna Hybrid (2021-) Lexus NX 350h/450h+ (2022-), RX 350h/450h+ (2023-), LM 350h (2023-)
Similarities to a regular CVT
- Both E-CVT and traditional CVT aim for infinite gear ratios to optimize engine efficiency.
- Its The only reason to keep the term “CVT” in E-CVT.
How a regular CVT works
- It uses a belt wedged between two cone-shaped pulleys. By changing the distance between the cones, the gear ratio is adjusted.
Additional points:
- The E-CVT design enables the car to theoretically reach similar speeds in both forward and reverse gears (limited by a governor in reverse for safety reasons).
- This technology is used in various hybrid vehicles beyond the Prius.
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