THS II (TOYOTA HYBRID SYSTEM II)
02HTH14TE
Hybrid
Transaxle
Front
Wheel
: Electrical Path
: Mechanical Power Path
Engine
Compound
Gear Unit
MG1
MG2
Inverter
Assembly
HV
Battery
When SOC level is low.
02DTH90Y
02DTH97Y
Sun Gear
(MG1)
Carrier
(Engine)
Ring Gear
(Output)
rpm
0
(+)
(+)
(+)
(-)
(-)
(-)
Sun Gear
(MG1)
Carrier
(Engine)
Ring Gear
(Output)
TH-15
5. During Low Load and Constant-Speed Cruising/(D)
When the vehicle is running under low load and constant-speed cruising conditions, the motive force of
the engine is transmitted by the planetary gears. Some of this motive force is output directly, and the
remaining motive force is used for generating electricity through MG1. Through the use of the electrical
path of an inverter, this electrical power is transmitted to MG2 to be output as the motive force of MG2.
If the SOC level of the HV battery is low, it is charged by MG1 driven by the engine.
The following represents an example of the power split planetary gear unit operation under normal driving
conditions. The sun gear, carrier and ring gear rotate in the (+) direction. The torque from the engine acts
on the carrier (Engine) in the (+) direction, causing the sun gear and ring gear to react in the (-) direction.
MG1 generates electricity by harnessing the (-) torque that acts on the sun gear.
The nomographic charts and the illustrations of the power split planetary gear unit operation for each
vehicle running condition shown on the following pages represent one situation as an example.
Nomographic Chart
Power Split Planetary Gear Unit Operation
Condition of Power Split Planetary Gear Unit
Sun Gear (MG1)
Carrier (Engine)
Ring Gear (Output)
Rotational Direction
+
+
+
Torque Condition
-
+
-
