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Isaac Zachary · 12-13-2020, 03:20 AM

From what I've read, the engine drives the planetary gears of the "power split device".

The ring gear around the planets is connected to both the Motor (MG2), which is on the output shaft, and the differential.

The Generator (MG1) is connected to the sun gear.

Powerwise

When the engine and all motor-generators are spinning the engine is feeding the planetary gears that splits 50% of it's power to the Generator (MG1) and the other 50% to the output shaft that the Motor (MG2) is connected to. How much of the Generator's (MG1's) output is directed to the battery or to the Motor (MG2) will affect total output.

For an example if the engine is supplying 100hp, 50hp go to the wheels an 50hp go to the generator. If all of that 50hp is directed to the motor, then you get 100hp (theoratically, if there werent' any losses) at the wheels.

But if 25hp is directed to the motor (MG2) and 25hp is directed to the HV battery, then 25hp + 50hp means you get 75hp at the wheels.

But if the motor (MG2) receives not only that 50hp power from the generator (MG1) but also another 50hp from the battery you now have 150hp at the wheels. (100hp from engine divided into 50hp MG1 and 50hp output shaft and the 50hp from MG1 and another 50hp from battery into MG2 that's on the output shaft = 150hp).

Speedwise

If the engine is spinning faster than the output shaft (MG2), then the Generator (MG1) is spinning that many times faster. For an example, Engine speed is 3,000RPM, output shaft (MG2) 2,000RPM, so Generator (MG1) is 4,000RPM.

If the engine is spinning the same speed as the output shaft (MG2), then the generator (MG1)is spinning the same speed, For an example: For an example, Engine speed is 4,000RPM, output shaft (MG2) 4,000RPM, so Generator (MG1) is 4,000RPM.

If the output shaft (MG2) is spinning faster than the engine then the Generator (MG1) is spinning that many times slower. For an example: Output shaft (MG2) is 3,000RPM, Engine is 4,000RPM so Generator (MG1) is 2,000RPM.

Any time the engine is spinning half the speed the output shaft (MG2) is the Generator (MG1) is stopped. For an example: Output shaft (Motor MG2) 2,000RPM, engine 1,000RPM so Generator (MG1) is 0RPM.

Any time the engine is less than half the speed the output shaft (MG2) is then the Generator (MG1) spins backwards. For an example: Output shaft (MG2) is 1,000RPM, Engine off 0RPM so Generator (MG2) is -1,000RPM.

As brought out before, the main challenge is probably thermal. Some have supercharged their Prii and found that they don't overpower the generator (MG1). It just tends to absorb a lot more power and they end up with a much more fully charged HV battery all the time. The Motor (MG2) should also be capable of delivering more power.

12-13-2020, 03:20 AM	#6 (permalink)
Isaac Zachary High Altitude Hybrid Join Date: Dec 2020 Location: Gunnison, CO Posts: 2,083 Avalon - '13 Toyota Avalon HV 90 day: 40.45 mpg (US) Prius - '06 Toyota Prius Thanks: 1,130 Thanked 585 Times in 464 Posts	From what I've read, the engine drives the planetary gears of the "power split device". The ring gear around the planets is connected to both the Motor (MG2), which is on the output shaft, and the differential. The Generator (MG1) is connected to the sun gear. Powerwise When the engine and all motor-generators are spinning the engine is feeding the planetary gears that splits 50% of it's power to the Generator (MG1) and the other 50% to the output shaft that the Motor (MG2) is connected to. How much of the Generator's (MG1's) output is directed to the battery or to the Motor (MG2) will affect total output. For an example if the engine is supplying 100hp, 50hp go to the wheels an 50hp go to the generator. If all of that 50hp is directed to the motor, then you get 100hp (theoratically, if there werent' any losses) at the wheels. But if 25hp is directed to the motor (MG2) and 25hp is directed to the HV battery, then 25hp + 50hp means you get 75hp at the wheels. But if the motor (MG2) receives not only that 50hp power from the generator (MG1) but also another 50hp from the battery you now have 150hp at the wheels. (100hp from engine divided into 50hp MG1 and 50hp output shaft and the 50hp from MG1 and another 50hp from battery into MG2 that's on the output shaft = 150hp). Speedwise If the engine is spinning faster than the output shaft (MG2), then the Generator (MG1) is spinning that many times faster. For an example, Engine speed is 3,000RPM, output shaft (MG2) 2,000RPM, so Generator (MG1) is 4,000RPM. If the engine is spinning the same speed as the output shaft (MG2), then the generator (MG1)is spinning the same speed, For an example: For an example, Engine speed is 4,000RPM, output shaft (MG2) 4,000RPM, so Generator (MG1) is 4,000RPM. If the output shaft (MG2) is spinning faster than the engine then the Generator (MG1) is spinning that many times slower. For an example: Output shaft (MG2) is 3,000RPM, Engine is 4,000RPM so Generator (MG1) is 2,000RPM. Any time the engine is spinning half the speed the output shaft (MG2) is the Generator (MG1) is stopped. For an example: Output shaft (Motor MG2) 2,000RPM, engine 1,000RPM so Generator (MG1) is 0RPM. Any time the engine is less than half the speed the output shaft (MG2) is then the Generator (MG1) spins backwards. For an example: Output shaft (MG2) is 1,000RPM, Engine off 0RPM so Generator (MG2) is -1,000RPM. As brought out before, the main challenge is probably thermal. Some have supercharged their Prii and found that they don't overpower the generator (MG1). It just tends to absorb a lot more power and they end up with a much more fully charged HV battery all the time. The Motor (MG2) should also be capable of delivering more power.