System Description: Description
To select the gear ratio that can give the driving force to meet driver's intent or vehicle situation, the vehicle driving condition such as vehicle speed or accelerator pedal position is detected and the most appropriate gear ratio is selected and the shifting method before reaching the speed is determined. The information is output to the primary pressure solenoid valve and secondary pressure solenoid valve to control the line pressure input/output to the pulley, to determine the pulley (movable pulley) position and to control the gear position.
Shift Position Function
- D Position (Normal)
Gear shifting is performed in all shifting ranges from the lowest to the highest gear ratio.
- D Position (OD OFF)
The gear ratio is generally high by limiting the shifting range on the high side, and this always generates a large driving power.
- L Position
By limiting the shifting range only to the lowest of the gear ratio, a large driving force and engine brake are obtained.
Hill Climbing And Descending Control
If a downhill is detected with the accelerator pedal is released, the system performs downshift to increase the engine brake force so that vehicle may not be accelerated more than necessary. If a climbing hill is detected, the system improves the acceleration performance in re-acceleration by limiting the gear shift range on the high side.
Control In Acceleration
From change of the vehicle speed or accelerator pedal position, the acceleration request level of the driver or driving scene is evaluated. In start or acceleration during driving, the gear shift characteristics with linearity of revolution increase and vehicle speed increase are gained to improve the acceleration feel.
Tow Mode
- In tow mode, sluggish acceleration and insufficient engine brake output resulting from towing are assisted and improved by CVT gear shifting.
- When all of the following conditions are satisfied, CVT goes into tow mode.
- Tow mode switch is ON
- When CVT judges a towing condition from vehicle behavior.
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Situation |
Operation |
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Road condition |
Brake pedal operation |
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Flat road |
Depressed |
To assist deceleration resulting from brake operation, the tow mode function increases engine revolution by shifting down and makes the engine brake effective. |
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Uphill |
-- |
In tow mode, the shift range on the HIGH side is limited more than that of normal mode and uphill driving control is improved. |
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Downhill |
Depressed |
To assist deceleration resulting from brake operation, the tow mode function increases engine revolution by shifting down more than the time when driving on flat roads and makes the engine brake effective. |