EP0092228A1 — Method and apparatus for controlling reduction ra…

Claim 1

Independent Claim 134 words

A method for controlling a reduction ratio of a continuously variable transmission of an automotive vehicle having an internal combustion engine, comprising: a) detecting at least one operating condition of the automotive vehicle; b) generating a desired optimum reduction ratio indicative signal representing a desired optimum reduction ratio for the detected operating condition of the automotive vehicle; c) generating an actual reduction ratio indicative signal representing an actual reduction ratio of the continuously variable transmission; d) comparing the actual reduction ratio indicative signal with the desired optimum reduction ratio indicative signal; e) adjusting the actual reduction ratio of the continuously variable transmission toward a value which agrees with said desired optimum reduction ratio, and f) repeating the steps c), d) and e) until the actual reduction ratio agrees with said desired optimum reduction ratio.

Claim 2

Independent Claim 134 words

A method for controlling a reduction ratio of a continuously variable transmission of an automotive vehicle having an internal combustion engine, comprising: a) detecting at least one operating condition of the automotive vehicle; b) generating a desired optimum reduction ratio indicative signal representing a desired optimum reduction ratio for the detected operating condition of the automotive vehicle; c) generating an actual reduction ratio indicative signal representing an actual reduction ratio of the continuously variable transmission; d) comparing the actual reduction ratio indicative signal with the desired optimum reduction ratio indicative signal; e) adjusting the actual reduction ratio of the continuously variable transmission toward a value which agrees with said desired optimum reduction ratio, and f) repeating the steps c), d) and e) until the actual reduction ratio agrees with said desired optimum reduction ratio.

Claim 3

Dependent Claim 32 words

A method as claimed in Claim 1, wherein said operating condition detecting step comprises: detecting the vehicle speed of the automotive vehicle; and detecting the engine load on the internal combustion engine.

Claim 4

Dependent Claim 34 words

A method as claimed in Claim 2, wherein the desired optimum reduction ratio is determined by the vehicle speed and a target engine revolution speed which satisfies a predetermined relationship with the engine load.

Claim 5

Dependent Claim 20 words

A method as claimed in Claim 3, wherein the engine load is determined by measuring the engine throttle opening degree.

Claim 6

Dependent Claim 19 words

A method as claimed in Claim 3, wherein the engine load is determined by measuring the intake manifold vacuum.

Claim 7

Dependent Claim 24 words

A method as claimed in Claim 3, wherein the engine load is determined by measuring the flow rate of fuel supplied to said engine.

Claim 8

Dependent Claim 23 words

A method as claimed in Claim 3, wherein said predetermined relationship allows the engine to always operate at the minimum fuel consumption rate.

Claim 9

Dependent Claim 59 words

A method as claimed in Claim 1, wherein said adjusting step comprises: effecting a step change in the actual reduction ratio of the continuously variable transmission; and generating a new actual reduction ratio indicative signal by changing the actual reduction ratio indicative signal in response to said step change in the actual reduction ratio of said continuously variable transmission.

Claim 10

Dependent Claim 54 words

A method as claimed in Claim 8, wherein the distortion of the actual reduction ratio indicative signal is eliminated by: generating a shift reference signal when the continuously variable transmission assumes a predetermined reduction ratio; and resetting the actual reduction ratio indicative signal to a predetermined value in response to the shift reference signal.

Claim 11

Dependent Claim 23 words

A method as claimed in Claim 9, wherein said predetermined reduction ratio is the largest reduction ratio and said predetermined value is zero.

Claim 12

Dependent Claim 37 words

A method as claimed in Claim 9, wherein said predetermined reduction ratio is smaller than the largest reduction ratio and said predetermined value corresponds to a difference between the predetermined reduction ratio and the largest reduction ratio.

Claim 13

Dependent Claim 117 words

A method as claimed in Claim 1, wherein the continuously variable transmission has a V-belt running over a cone pulley having a conical surface on which the V-belt contacts and means for providing the tension on the V-belt, the cone pulley having a cylinder chamber and two conical discs, one conical disc thereof being secured to a shaft, the other conical disc of the cone pulley being controllably movable in an axial direction of the shaft in response to the fluid pressure in the cylinder chamber thereof, and wherein the reduction ratio is controlled by regulating fluid supply to and discharge from said cylinder chamber by means of a shift control valve actuated by a shift motor.

Claim 14

Dependent Claim 160 words

A method as claimed in Claim 1, wherein the continuously variable transmission has a V-belt running over a drive pulley and a driven pulley, each having a cylinder chamber and two conical discs, one conical disc of the drive pulley being secured to a drive shaft adapted to be driven by the engine, one conical disc of the driven pulley being secured to a driven shaft, the other conical disc of the drive pulley being controllably movable in an axial direction of the drive shaft in response to the fluid pressure in the cylinder chamber thereof, the other conical disc of the driven pulley being controllably movable in an axial direction of the driven shaft in response to the fluid pressure in the cylinder chamber thereof, and wherein the reduction ratio is controlled by regulating fluid supply to and discharge from at least one of said cylinder chambers by means of a shift control valve actuated by a shift motor.

Claim 15

Dependent Claim 15 words

A method as claimed in Claim 13, wherein the shift motor is a stepper motor.

Claim 16

Independent Claim 119 words

An apparatus for controlling a reduction ratio of a continuously variable transmission of an automotive vehicle having an internal combustion engine, comprising: means for detecting at least one operating condition of the automotive vehicle; means for generating a desired optimum reduction ratio indicative signal representing a desired optimum reduction ratio for the detected operating condition of the automotive vehicle; means for generating an actual reduction ratio indicative signal representing an actual reduction ratio of the continuously variable transmission; means for comparing the actual reduction ratio indicative signal with the desired optimum reduction ratio indicative signal; and means for adjusting the actual reduction ratio of the continuously variable transmission toward a value which agrees with said desired optimum reduction ratio.

Claim 17

Independent Claim 119 words

An apparatus for controlling a reduction ratio of a continuously variable transmission of an automotive vehicle having an internal combustion engine, comprising: means for detecting at least one operating condition of the automotive vehicle; means for generating a desired optimum reduction ratio indicative signal representing a desired optimum reduction ratio for the detected operating condition of the automotive vehicle; means for generating an actual reduction ratio indicative signal representing an actual reduction ratio of the continuously variable transmission; means for comparing the actual reduction ratio indicative signal with the desired optimum reduction ratio indicative signal; and means for adjusting the actual reduction ratio of the continuously variable transmission toward a value which agrees with said desired optimum reduction ratio.

Claim 18

Dependent Claim 36 words

An apparatus as claimed in Claim 15, wherein said operating condition detecting means comprises: means for detecting the vehicle speed of the automotive vehicle; and means for detecting the engine load on the internal combustion engine.

Claim 19

Dependent Claim 33 words

An apparatus as claimed in Claim 16, wherein the desired reduction ratio is determined by the vehicle speed and a target engine revolution speed which satisfies a predetermined relationship with the engine load.

Claim 20

Dependent Claim 20 words

An apparatus as claimed in Claim 17, wherein the engine load is determined by measuring the engine throttle opening degree.

Claim 21

Dependent Claim 19 words

An apparatus as claimed in Claim 17, wherein the engine load is determined by measuring the intake manifold vacuum.

Claim 22

Dependent Claim 24 words

An apparatus as claimed in Claim 17, wherein the engine load is determined by measuring the flow rate of fuel supplied to said engine.

Claim 23

Dependent Claim 23 words

An apparatus as claimed in Claim 17, wherein said predetermined relationship allows the engine to always operate at the minimum fuel consumption rate.

Claim 24

Dependent Claim 116 words

An apparatus as claimed in Claim 15, wherein the continuously variable transmission has a V-belt running over a cone pulley having a conical surface on which the V-belt contacts and means for providing the tension on the V-belt, the cone pulley having a cylinder chamber and two conical discs, one conical disc thereof secured to a shaft, the other conical disc of the cone pulley being controllably movable in an axial direction of the shaft' in response to the fluid pressure in the cylinder chamber thereof, and wherein the reduction ratio is controlled by regulating fluid supply to and discharge from said cylinder chamber by means of a shift control valve actuated by a shift motor.

Claim 25

Dependent Claim 160 words

An apparatus as claimed in Claim 15, wherein the continuously variable transmission has a V-belt running over a drive pulley and a driven pulley, each having a cylinder chamber and two conical discs, one conical disc of the drive pulley being secured to a drive shaft adapted to be driven by the engine, one conical disc of the driven pulley being secured to a driven shaft, the other conical disc of the drive pulley being controllably movable in an axial direction of the drive shaft in response to the fluid pressure in the cylinder chamber thereof, the other conical disc of the driven pulley being controllably movable in an axial direction of the driven shaft in response to the fluid pressure in the cylinder chamber thereof, and wherein the reduction ratio is controlled by regulating fluid supply to and discharge from at least one of said cylinder chambers by means of a shift control valve actuated by a shift motor.

Claim 26

Dependent Claim 15 words

An apparatus as claimed in Claim 23, wherein the shift motor is a stepper motor.

Method and apparatus for controlling reduction ratio of continuously variable transmission

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