Two motor power-split hybrid system with selectable one-way clutch enabled lockable planetary gear sets for two-speed dual motor EV and engine plus dual motor drive modes
A hybrid drive train includes a first electric motor, a nested power splitting planetary gear set having a first carrier element and a second carrier element, an inner sun gear coupled with the first electric motor and an outer sun gear coupled with an output shaft. A first selectable one-way clutch controls the first and the second carrier element, and switches between operation as a one way clutch and operation as a brake. A second selectable one-way clutch controls a ring gear of the nested planetary gear set, and switches between operation as a one way clutch and operation as a brake. The extra outer planetary gear set improves towing capacity at higher speeds without substantially increasing the axial length of the power split device.
1. A hybrid drive train, comprising:
an input shaft that inputs motive power from an internal combustion engine;
an output shaft that outputs to driving wheels;
a first electric motor;
a power splitting planetary gear set;
a second electric motor coupled with the output shaft;
a first selectable one-way clutch configured to operate as a one way clutch,
a second selectable one-way clutch configured to operate as a brake; wherein:
the power splitting gear set operates in a first operating mode such that the second electric motor drives the wheels;
the power splitting gear set operates in a second operating mode to drive the wheels in power-split; and
the power splitting gear set operates in a third operating mode to drive the wheels at a speed that is faster than the second operating mode.
2. The hybrid drive train of claim 1 , wherein
the power splitting planetary gear set is
a nested power splitting planetary gear set comprising a first carrier element and a second carrier element coupled with the input shaft, an inner sun rotary element coupled with the first electric motor and an outer sun rotary element coupled with the output shaft;
the first selectable one-way clutch is further configured to control the first and the second carrier element, the first selectable one-way clutch configured to switch between operation as the one way clutch and operation as a brake,
the second selectable one-way clutch is further configured to control a ring rotary element of the nested power splitting planetary gear set, the second selectable one-way clutch is further configured to switch between operation as a one way clutch and operation as the brake;
and wherein
the nested power splitting planetary gear set operates in the first operating mode in which the first selectable one-way clutch operates as a brake while the second selectable one-way clutch is released and the second electric motor drives the wheels;
the nested power splitting planetary gear operates in the second operating mode in which the second selectable one-way clutch operates as a brake while the first selectable one-way clutch is released to drive the wheels in power-split; and
the nested power splitting planetary gear operates in the third operating mode in which the first selectable one-way clutch is released and the second selectable one-way clutch is released to drive the wheels at a speed that is faster than the second operating mode.
3. The hybrid driver of claim 2 , wherein in the first operating mode in which the first selectable one-way clutch operates as a brake while the second selectable one-way clutch is released, the first selectable one-way clutch operates as a brake to stop rotation of the ring rotary element which stops rotation of the internal combustion engine.
4. The hybrid driver of claim 2 , wherein in the second operating mode in which the second selectable one-way clutch operates as a brake while the first selectable one-way clutch is released, the second selectable one-way clutch operates as a brake to stop rotation of the ring rotary element while allowing the internal combustion engine to rotate.
5. The hybrid driver of claim 2 , wherein in the third operating mode in which the first selectable one-way clutch and the second selectable one-way clutch are released, the first motor generator, the second motor generator and the internal combustion engine supply power to drive the wheels.
6. The hybrid drive train of claim 1 , wherein
the power splitting gear set includes
a first planetary gear set comprising a first carrier element, a sun rotary element coupled with the first electric motor and a ring rotary element coupled with the output shaft; and
a second planetary gear set comprising a sun rotary element coupled with the input shaft, a ring rotary element and a second carrier element coupled with the first carrier element;
the first selectable one-way clutch further configured to control the sun rotary element of the second planetary gear, the second selectable one-way clutch further configured to control the ring rotary element of the second planetary gear set, and wherein:
the power splitting gear set operates in the first operating mode in which the second selectable one-way clutch operates as a brake and the first selectable one-way clutch is locked such that the second electric motor drives the wheels;
the power splitting gear set operates in the second operating mode in which the first selectable one-way clutch is released while the second selectable one-way clutch operates as the brake to drive the wheels in power-split; and
the power splitting gear set operates in the third operating mode in which the first selectable one-way clutch is locked while the second selectable one-way clutch is released to drive the wheels at a speed that is faster than the second operating mode.
7. The hybrid driver of claim 6 , wherein in the first operating mode in which the second selectable one-way clutch operates as a brake and the first selectable one-way clutch is locked, the second selectable one-way clutch is locked to operate as a brake, stopping rotation of the ring rotary element of the second planetary gear set, and the first selectable one-way clutch is locked to stop rotation of the sun rotary element of the second planetary gear set, and thus the engine does not rotate.
8. The hybrid driver of claim 6 , wherein in the second operating mode in which the first selectable one-way clutch is released while the second selectable one-way clutch operates as a brake, the second selectable one-way clutch remains locked to operate as a brake while the first selectable one-way clutch is disengaged which allows the engine to be rotated by way of the sun rotary element of the second planetary gear set.
9. The hybrid driver of claim 6 , wherein in the third operating mode in which the first selectable one-way clutch is locked while the second selectable one-way clutch is released,
wherein the engine drives the second planetary gear, which together with assistance of driving force from the first motor generator rotate a common carrier coupling the second carrier element with the first carrier element such that the speed of the engine is controlled to stay in an optimal speed range while the speed of the first and second motor generators are used to supplement the engine to control speed of the wheels.