Continuously variable transmission control system

Claim 2

A ratio control system for a continuously variable transmission which is shiftable from a present reduction ratio to a target reduction ratio, comprising: a control unit for executing a feedback control equation involving at least one gain and an input turbine speed deviation which is stored in said control unit, said gain being variable with a first time derivative of said target reduction ratio, and said control unit producing an output signal which is determined by said feedback equation; and means for shifting said transmission in response to said output signal.

Claim 3

A ratio control system as claimed in claim 1, wherein the gain is larger when said first time derivative of the target reduction ratio is relatively large than when said first time derivative of the target reduction ratio is relatively small.

Claim 4

A ratio control system for a continuously variable transmission which is shiftable from a present reduction ratio to a target reduction ratio, comprising: a control unit for executing a feedback control equation involving a proportional gain, an integral gain, and an input turbine speed deviation which is stored in said control unit, said gain being variable with a first time derivative of said target reduction ratio, and said control unit producing an output signal which is determined by said feedback equation; and means for shifting said transmission in response to said output signal.

Claim 5

A ratio control system for a continuously variable transmission which is shiftable from a present reduction ratio to a target reduction ratio, comprising: a control unit for executing a feedback control equation involving a proportional gain, an integral gain, and an input turbine speed deviation which is stored in said control unit, said gain being variable with a first time derivative of said target reduction ratio, and said control unit producing an output signal which is determined by said feedback equation; and means for shifting said transmission in response to said output signal.

Claim 6

A ratio control system as claimed in claim 3, wherein the proportional and integral gains are larger when said first time derivative of the target reduction ratio is relatively large than when said first time derivative of the target reduction ratio is relatively small.

Claim 7

A ratio control system for a continuously variable transmission in a motor vehicle, the continuously variable transmission having an input member and being shiftable from a present reduction ratio to a target reduction ratio, the ratio control system comprising: means for detecting a revolution speed of the input member and generating an input revolution speed indicative signal which is indicative of the revolution speed detected; a control unit operatively coupled with said revolution speed detecting means, said control unit receiving said input revolution speed indicative signal and generating an output signal; and means for effecting a shift in reduction ratio in said continuously variable transmission in response to said output signal, wherein said control unit further includes means for determining a first time derivative of said target reduction ratio; means for determining a target input revolution speed of the input member and generating a target input revolution speed indicative signal which is indicative of said target revolution speed determined; means for storing a feedback control equation involving gains and a deviation between said input revolution speed indicative signal and said target input revolution speed indicative signal; means for generating said output signal after calculating said feedback control equation, and means for varying said gains in response to said first time derivative of said target reduction ratio.

Claim 8

A ratio control system for a continuously variable transmission in a motor vehicle, the continuously variable transmission having an input member and being shiftable from a present reduction ratio to a target reduction ratio, the ratio control system comprising: means for detecting a revolution speed of the input member and generating an input revolution speed indicative signal which is indicative of the revolution speed detected; a control unit operatively coupled with said revolution speed detecting means, said control unit receiving said input revolution speed indicative signal and generating an output signal; and means for effecting a shift in reduction ratio in said continuously variable transmission in response to said output signal, wherein said control unit further includes means for determining a first time derivative of said target reduction ratio; means for determining a target input revolution speed of the input member and generating a target input revolution speed indicative signal which is indicative of said target revolution speed determined; means for storing a feedback control equation involving gains and a deviation between said input revolution speed indicative signal and said target input revolution speed indicative signal; means for generating said output signal after calculating said feedback control equation, and means for varying said gains in response to said first time derivative of said target reduction ratio.

Claim 9

A ratio control system as claimed in claim 5, further comprising means for detecting a vehicle speed of the motor vehicle and generating a vehicle speed indicative signal which is indicative of said vehicle speed detected, wherein said control unit includes means for determining the target reduction ratio after dividing said input revolution speed indicative signal by said vehicle speed indicative signal.

Claim 10

A ratio control system as claimed in claim 6, wherein said gains are a proportional gain and an integral gain.

Claim 13

A method as claimed in claim 8, wherein, in said step (c), said proportional and integral gains increase in response to an increase in said first time derivative of said target value.

Claim 14

A method as claimed in claim 8, wherein, in said step (c) said proportional and integral gains are proportional to said first time derivative of said target value.

Claim 15

A method as claimed in claim 8, wherein, said step (a) further includes the steps of: determining a target input revolution speed of an input member of the continuously variable transmission; detecting a vehicle speed of the motor vehicle; and determining said target value as a function of said target input revolution speed and said vehicle speed.

Claim 16

A method as claimed in claim 11, further comprising the steps of: detecting an actual input revolution speed of the input member of the continuously variable transmission; and repeatedly determining a deviation between said actual revolution speed and said target revolution speed.

Claim 17

A method as claimed in claim 12, wherein said feedback control equation involves said deviation as a variable.