4 ms·
It's genius in it simplicity. The car doesn't actually have a transmission and uses planetary gear sets and two electric motors to fake one. The gasoline engin
by oppositelock 8y ago
It's genius in it simplicity. The car doesn't actually have a transmission and uses planetary gear sets and two electric motors to fake one.
The gasoline engine is used as the "baseline" power, and the motors then either take power away from it to charge the batteries, or complement it to help in acceleration, or just bypass it completely.
When the car is running in pure electric mode, the gas engine is stopped, and the motors work together to spin the output shaft at the desired speed.
When the car is using mixed power, the gasoline engine is working at a desired power level, one of the motor/generators is adding additional torque, and the second motor is used to make up the rotational difference between the sun and planet gears. This blending of gasoline and electric allows the wheel output speed to be independent of the gasoline engine speed.
When the car is charging the battery, the gasoline engine is run harder than it needs to be to move the car, and one of the motor/generator units is fighting against it, using the excess torque to generate power.
So, there is no transmission, no "shifting", the engine and mgu's are permanently connected to gears and simply spin them at the right speeds for the desired power and speed output.
- konschubert 8y agoThis is standard since decades in non-electric train engines. https://en.wikipedia.org/wiki/Diesel–electric_transmission https://en.wikipedia.org/wiki/Diesel–electric_transmission
- CarVac 8y agoToyota's hybrid system differs from trains in that there's a direct mechanical connection from the engine to the wheels, boosting efficiency by not requiring all of the power to go through the motors.
- ProfessorLayton 8y agoThat is incorrect. Toyota's Hybrid Synergy Drive is able to power the wheels with either 100% electric, or 100% gas, or a combination of the two using planetary gears. This allows the use of a more efficient engine running the Atkinson cycle, with the electric motors filling in for the reduced low-end torque. At highway speeds the engine is driving the wheels directly, which is more efficient than converting torque to electric power to drive an electric motor. Honda's two-motor system runs much like the transmission you linked, but again drives the wheels directly at highway speeds.
- konschubert 8y agoI must have misunderstood the GP then, sorry :(
- marcinzm 8y agoThe Toyota system seems fairly different than a diesel-electric train system to me. As I understand it in a diesel electric system the three components (diesel engine, generator and electric motor) all do one thing the whole time and there's no batteries. In the Toyota system however the electric motors can flexibly act as either motors or generators. The gas engine in Toyota also doesn't need to always be on to provide power.