JBee
Well-known member
- First Name
- JB
- Joined
- Nov 22, 2019
- Threads
- 18
- Messages
- 4,774
- Reaction score
- 6,148
- Location
- Australia
- Vehicles
- Cybertruck
- Occupation
- . Professional Hobbyist
A variation of the planetary gear is also commonly used on every single Tesla produced to date, in the form of a differential.
A planetary gear provides much greater ratios than a single gear gearbox can, and is ideal for compact high rpm motors (like the plaid) being used in high torque vehicles like the semi. This is also because it has three times the gear tooth area, meaning that individual gears can be smaller and lighter than a comparable single gear. Lucid Air drivetrain employs these in such a way, to make a super compact drivetrain, and the CT might even use them on the QM.
The planetary gear in a Prius was completely necessary so that a ICE could run in a Hybrid Prius at all. It had nothing to do with the electric motor side as such, but that doesn't mean that a EV can't benefit from having a planetary gear, if a higher ratio is required. Planetary gear is not related to ICE drivetrains as such, except for he Prius hybrid drivetrain types.
This is because it had NO active clutch or any way to disengage the engine from driving the wheels, except that one electric motor would spin backwards as fast as the engine would spin forwards, resulting in the wheels not turning. It was also limited to electric only reverse (the engine could idle still). The unique features of a planetary gear allowed it to do this by driving some parts of the planetary gear with the two electric motors and the third moving part by the engine. Even whilst driving forwards one of the electric motors would spin backwards to create the necessary ratio for the Atkinson cycle ICE to sit in it's most efficient RPM band.
You can find out more here on how it works. It's probably the simplest and most effective gearbox without a clutch design there is, and has virtually no extra efficiency loss in EV only mode.
http://eahart.com/prius/psd/
A planetary gear provides much greater ratios than a single gear gearbox can, and is ideal for compact high rpm motors (like the plaid) being used in high torque vehicles like the semi. This is also because it has three times the gear tooth area, meaning that individual gears can be smaller and lighter than a comparable single gear. Lucid Air drivetrain employs these in such a way, to make a super compact drivetrain, and the CT might even use them on the QM.
The planetary gear in a Prius was completely necessary so that a ICE could run in a Hybrid Prius at all. It had nothing to do with the electric motor side as such, but that doesn't mean that a EV can't benefit from having a planetary gear, if a higher ratio is required. Planetary gear is not related to ICE drivetrains as such, except for he Prius hybrid drivetrain types.
This is because it had NO active clutch or any way to disengage the engine from driving the wheels, except that one electric motor would spin backwards as fast as the engine would spin forwards, resulting in the wheels not turning. It was also limited to electric only reverse (the engine could idle still). The unique features of a planetary gear allowed it to do this by driving some parts of the planetary gear with the two electric motors and the third moving part by the engine. Even whilst driving forwards one of the electric motors would spin backwards to create the necessary ratio for the Atkinson cycle ICE to sit in it's most efficient RPM band.
You can find out more here on how it works. It's probably the simplest and most effective gearbox without a clutch design there is, and has virtually no extra efficiency loss in EV only mode.
http://eahart.com/prius/psd/
Sponsored
Last edited:
