A transmission control device includes a converter that converts continuous accelerator positions detected by an accelerator pedal sensor into a stepped step position, and a controller that controls the gear ratio of a continuously variable transmission based on the converted step position. The converter creates a hysteresis regarding the converted step position, when the accelerator depression amount increases, and when the accelerator depression amount decreases. In the case where the step position reaches a predetermined position or greater, the controller executes kick-down control where the gear ratio is controlled to a low side.

Described herein is a control system for a vehicle having a continuously variable transmission (CVT) having a ball planetary variator (CVP), providing a smooth and controlled operation. In some embodiments, the control system implements an optimization sub-module. System losses in a CVP equipped vehicle consist of the following: CVP efficiency losses, hydraulic pump losses, clutch energy losses, mode shift losses, torque converter losses, and engine losses (defined as deviation from best Brake Specific Fuel Consumption point), among others. Driver torque demand can be satisfied by an infinite combination of operating points consisting of a chosen engine operating point, CVP ratio, and mode selection. The required clamping load and line pressure requirements resulting from these choices further influences losses. Methods described herein select a system operating point that minimizes total system losses.

An apparatus and method are disclosed for controlling fluid flow to a variator which responsive to separate high and low pressure fluids to control an output torque thereof. A first trim valve may be responsive to a first control signal to supply a first fluid at a fluid outlet thereof. A second trim valve may be responsive to a second control signal to supply a second fluid at a fluid outlet thereof. A variator switching sub-system may controllably supply the high pressure fluid and the low pressure fluid to the variator. A multiplex valve may be fluidly coupled to the outlets of the first and second trim valves, and may supply the first fluid as the high pressure fluid to the variator switching sub-system during at least one predefined operating condition and may otherwise supply the second fluid as the high pressure fluid to the variator switching sub-system.

An apparatus for controlling a variator having at least one roller between two torroidal disks may include at least one actuator responsive to fluid pressure at separate high side and low side fluid inlets thereof to control torque applied by the at least one roller to the disks. First and second variator switching valves may each receive a first fluid at a first pressure and a second fluid at a second lesser pressure. The first and second variator switching valves supply the first fluid to the high side fluid inlet and the second fluid to the low side fluid inlet during two of four different operational states together defined by the variator switching valves, and supply the second fluid to the high side fluid inlet and the first fluid to the low side fluid inlet during each of the remaining two of the four different operational states.

In order to reduce the amount of time from when signals are sent to solenoid valves 19, 23, 24 for adjusting hydraulic pressures inside hydraulic pressure chambers of various hydraulic devices 7, 8, 14 assembled in a continuously variable transmission device until the hydraulic pressures are actually changed is shortened, the solenoid valves 19, 23, 24 adjust the hydraulic pressures inside hydraulic pressure chambers connected to hydraulic introduction paths where the solenoid valves 19, 23, 24 are provided by adjusting apertures of the solenoid valves 19, 23, 24 set according to duty cycles, and a controller 16 for the solenoid valves 19, 23, 24, when the apertures of solenoid valves 19, 23, 24 are changed beyond specified values to desired apertures, adjusts the apertures beyond the desired apertures to a state where the apertures have been changed a maximum amount, then after a specified amount of time, returns the apertures to the desired apertures.