Downshift with power in continuously variable transmission

Claim 1

A method of controlling a reduction ratio in a continuously variable transmission drivingly connected to an engine of a vehicle having an accelerator manually operable by a driver of the vehicle, the continuously variable transmission having an actuator movable from a first operating position to a second operating postion and hydraulic means for varying the reduction ratio from a first ratio state corresponding to the first operating position to a second ratio state corresponding to the second operating position, the method comprising the steps of: detecting a first predetermined operating variable indicative of a power demand imposed on the accelerator by the driver and generating a power demand indicative signal indicative of said first predetermined operating variable detected; detecting an actual value of a second predetermined operating variable and generating an actual value indicative signal indicative of said actual value detected; setting a target value of said second predetermined operating variable in response to said power demand indicative signal; determining a feedforward value in response to said target value; determining a deviation between said actual value and said target value; determining a feedback value in response to said deviation; determining whether there has occurred a demand for downshift with power from said power demand indicative signal; setting, as an output signal, a sum of said feedforward value and said feedback value until occurrence of said demand; setting as said output signal, said feedforward value only in response to said occurrence of said demand by neglecting said feedback value; and controlling the actuator in response to said output signal.

Claim 2

A method of controlling a reduction ratio in a continuously variable transmission drivingly connected to an engine of a vehicle having an accelerator manually operable by a driver of the vehicle, the continuously variable transmission having an actuator movable from a first operating position to a second operating postion and hydraulic means for varying the reduction ratio from a first ratio state corresponding to the first operating position to a second ratio state corresponding to the second operating position, the method comprising the steps of: detecting a first predetermined operating variable indicative of a power demand imposed on the accelerator by the driver and generating a power demand indicative signal indicative of said first predetermined operating variable detected; detecting an actual value of a second predetermined operating variable and generating an actual value indicative signal indicative of said actual value detected; setting a target value of said second predetermined operating variable in response to said power demand indicative signal; determining a feedforward value in response to said target value; determining a deviation between said actual value and said target value; determining a feedback value in response to said deviation; determining whether there has occurred a demand for downshift with power from said power demand indicative signal; setting, as an output signal, a sum of said feedforward value and said feedback value until occurrence of said demand; setting as said output signal, said feedforward value only in response to said occurrence of said demand by neglecting said feedback value; and controlling the actuator in response to said output signal.

Claim 7

A system for controlling a reduction ratio in a continuously variable transmission drivingly connected to an engine of a vehicle having an accelerator manually operable by a driver of the vehicle, the continuously variable transmission having an actuator movable from a first operating position to a second operating position and hydraulic means for varying the reduction ratio from a first ratio state corresponding to the first operating position to a second ratio state corresponding to the second operating position, the system comprising: means for detecting a first predetermined operating variable indicative of a power demand imposed on the accelerator by the driver and generating a power demand indicative signal indicative of said first predetermined operating variable detected; means for detecting an actual value of a second predetermined operating variable and generating an actual value indicative signal indicative of said actual value detected; and a control unit comprising means for setting a target value of said second predetermined operating variable in response to said power demand indicative signal; means for determining a feedforward value in response to said target value; means for determining a deviation between said actual value and said target value; means for determining a feedback value in response to said deviation; means for determining whether there has occurred a demand for downshift with power from said power demand indicative signal; means for setting, as an output signal, a sum of said feedforward value and said feedback value until occurrence of said demand; means for setting, as said output signal, said feedforward value only in response to said occurrence of said demand by neglecting said feedback value; and means for controlling the actuator in response to said output signal.

Claim 8

A system for controlling a reduction ratio in a continuously variable transmission drivingly connected to an engine of a vehicle having an accelerator manually operable by a driver of the vehicle, the continuously variable transmission having an actuator movable from a first operating position to a second operating position and hydraulic means for varying the reduction ratio from a first ratio state corresponding to the first operating position to a second ratio state corresponding to the second operating position, the system comprising: means for detecting a first predetermined operating variable indicative of a power demand imposed on the accelerator by the driver and generating a power demand indicative signal indicative of said first predetermined operating variable detected; means for detecting an actual value of a second predetermined operating variable and generating an actual value indicative signal indicative of said actual value detected; and a control unit comprising means for setting a target value of said second predetermined operating variable in response to said power demand indicative signal; means for determining a feedforward value in response to said target value; means for determining a deviation between said actual value and said target value; means for determining a feedback value in response to said deviation; means for determining whether there has occurred a demand for downshift with power from said power demand indicative signal; means for setting, as an output signal, a sum of said feedforward value and said feedback value until occurrence of said demand; means for setting, as said output signal, said feedforward value only in response to said occurrence of said demand by neglecting said feedback value; and means for controlling the actuator in response to said output signal.

Claim 11

A method of controlling a reduction ratio in a continuously variable transmission drivingly connected to an engine of a vehicle having an accelerator manually operable by a driver of the vehicle, the continuously variable transmission having an actuator movable from a first operating position to a second operating position and hydraulic means for varying the reduction ratio from a first ratio state corresponding to the first operating position to a second ratio state corresponding to the second operating position, the method comprising the steps of: detecting a first predetermined operating variable indicative of a power demand imposed on the accelerator by the driver and generating a power demand indicative signal indicative of said first predetermined operating variable detected; detecting an actual value of a second predetermined operating variable and generating an actual value indicative signal indicative of said actual value detected; setting a target value of said second predetermined operating variable in response to said power demand indicative signal; determining a feedforward value in response to said target value; determining a deviation between said actual value and said target value; detecting an increase in said power demand indicative signal; comparing the absolute value of said deviation with a first predetermined value; setting a demand for downshift with power when, as a result of said comparing step of said deviation with said first predetermined value, said absolute value of said deviation is greater than said first predetermined value after detecting said increase in said power demand indicative signal; resetting said demand for downshift with power when, as a result of said comparing step of said deviation with said first predetermined value, said absolute value of said deviation is less than or equal to said first predetermined value; setting said feedforward value as an output signal when said demand for downshift with power is set; comparing the absolute value of said deviation with a second predetermined value that is greater than said first predetermined value; determining a first feedback value in response to said deviation when, as a result of said comparing step of comparing the absolute value of said deviation with said second predetermined value, the absolute value of said deviation is greater than or equal to said second predetermined value under a condition when said demand is reset; determining a second feedback value when, as a result of said comparing step of said absolute value of said deviation with said second predetermined value, the absolute value of said deviation is less than said second predetermined value under the condition when said demand is reset; setting a sum of said feedforward value and said first feedback value as said output signal when, as a result of said comparing step of comparing the absolute value of said deviation with said second predetermined value, the absolute value of said deviation is greater than or equal to said second predetermined value under a condition when said demand is reset; setting a sum of said feedforward value and said second feedback value as said output signal when, as a result of said comparing step of said absolute value of said deviation with said second predetermined value, the absolute value of said deviation is less than said second predetermined value under the condition when said demand is rest; and controlling the actuator in response to said output signal.

Claim 12

A method of controlling a reduction ratio in a continuously variable transmission drivingly connected to an engine of a vehicle having an accelerator manually operable by a driver of the vehicle, the continuously variable transmission having an actuator movable from a first operating position to a second operating position and hydraulic means for varying the reduction ratio from a first ratio state corresponding to the first operating position to a second ratio state corresponding to the second operating position, the method comprising the steps of: detecting a first predetermined operating variable indicative of a power demand imposed on the accelerator by the driver and generating a power demand indicative signal indicative of said first predetermined operating variable detected; detecting an actual value of a second predetermined operating variable and generating an actual value indicative signal indicative of said actual value detected; setting a target value of said second predetermined operating variable in response to said power demand indicative signal; determining a feedforward value in response to said target value; determining a deviation between said actual value and said target value; detecting an increase in said power demand indicative signal; comparing the absolute value of said deviation with a first predetermined value; setting a demand for downshift with power when, as a result of said comparing step of said deviation with said first predetermined value, said absolute value of said deviation is greater than said first predetermined value after detecting said increase in said power demand indicative signal; resetting said demand for downshift with power when, as a result of said comparing step of said deviation with said first predetermined value, said absolute value of said deviation is less than or equal to said first predetermined value; setting said feedforward value as an output signal when said demand for downshift with power is set; comparing the absolute value of said deviation with a second predetermined value that is greater than said first predetermined value; determining a first feedback value in response to said deviation when, as a result of said comparing step of comparing the absolute value of said deviation with said second predetermined value, the absolute value of said deviation is greater than or equal to said second predetermined value under a condition when said demand is reset; determining a second feedback value when, as a result of said comparing step of said absolute value of said deviation with said second predetermined value, the absolute value of said deviation is less than said second predetermined value under the condition when said demand is reset; setting a sum of said feedforward value and said first feedback value as said output signal when, as a result of said comparing step of comparing the absolute value of said deviation with said second predetermined value, the absolute value of said deviation is greater than or equal to said second predetermined value under a condition when said demand is reset; setting a sum of said feedforward value and said second feedback value as said output signal when, as a result of said comparing step of said absolute value of said deviation with said second predetermined value, the absolute value of said deviation is less than said second predetermined value under the condition when said demand is rest; and controlling the actuator in response to said output signal.