Method of controlling speed change clutches in a transmission

Claim 1

A method of controlling a plurality of speed change clutches which are to be incorporated in a transmission of a vehicle, said method being adapted to be applied to said transmission, characterized in that said speed change clutches are controlled by the following steps: (a) establishing a target value of jerk value; (b) predetermining, for each speed change stage, a relation among a clutch hydraulic pressure to be applied to one of said plurality of speed change clutches to be brought into the engaged state when an intended speed stage is selected, a clutch disc relative revolution number of said one of the speed change clutches and an amount of throttling for causing said jerk value to be said target value; (c) sensing vehicle weight and determining an increase gradient of a clutch hydraulic pressure to be applied to said one of the speed change clutches in accordance with said vehicle weight and a speed stage to be selected such that jerk value becomes said target value; (d) causing said clutch hydraulic pressure applied to said one of the speed change clutches to be brought into the engaged state to gradually increase in accordance with said increase gradient; (e) sensing said clutch hydraulic pressure, said disc relative revolution number and said amount of throttling, and maintaining said clutch hydraulic pressure at a value as measured at a first time point when said clutch hydraulic pressure, said disc relative revolution number and said amount of throttling establish said predetermined value; and (f) causing said clutch hydraulic pressure to increase to a level of specified pressure at a second time point when said disc relative revolution number is decreased to a level of zero.

Claim 2

A method of controlling a plurality of speed change clutches which are to be incorporated in a transmission of a vehicle, said method being adapted to be applied to said transmission, characterized in that said speed change clutches are controlled by the following steps: (a) establishing a target value of jerk value; (b) predetermining, for each speed change stage, a relation among a clutch hydraulic pressure to be applied to one of said plurality of speed change clutches to be brought into the engaged state when an intended speed stage is selected, a clutch disc relative revolution number of said one of the speed change clutches and an amount of throttling for causing said jerk value to be said target value; (c) sensing vehicle weight and determining an increase gradient of a clutch hydraulic pressure to be applied to said one of the speed change clutches in accordance with said vehicle weight and a speed stage to be selected such that jerk value becomes said target value; (d) causing said clutch hydraulic pressure applied to said one of the speed change clutches to be brought into the engaged state to gradually increase in accordance with said increase gradient; (e) sensing said clutch hydraulic pressure, said disc relative revolution number and said amount of throttling, and maintaining said clutch hydraulic pressure at a value as measured at a first time point when said clutch hydraulic pressure, said disc relative revolution number and said amount of throttling establish said predetermined value; and (f) causing said clutch hydraulic pressure to increase to a level of specified pressure at a second time point when said disc relative revolution number is decreased to a level of zero.

Claim 5

A method of controlling a plurality of speed change clutches which are to be incorporated in a transmission of a vehicle, said method being adapted to be applied to said transmission, characterized in that said speed change clutches are controlled by the following steps: (a) at a time point when a speed change command is issued, feeding one of said plurality of speed change clutches to be subsequently brought into the engaged state with hydraulic oil; (b) at the time point when said speed change command is issued, calculating both output torque from said transmission just before speed change and output torque from said transmission immediately after speed change, respectively; (c) calculating a clutch hydraulic pressure to equalize said output torques; (d) sensing the termination of filling time with respect to said one of speed change clutches to be subsequently brought into the engaged state; and (e) causing said hydraulic pressure to decrease in the speed change clutch which is presently brought in the engaged state while exerting said calculating clutch hydraulic pressure on said one of speed change clutch to be subsequently brought into engaged state and thereafter causing said clutch hydraulic pressure to increase gradually on said speed change clutch.

Claim 6

A method of controlling a plurality of speed change clutches which are to be incorporated in a transmission of a vehicle, said method being adapted to be applied to said transmission, characterized in that said speed change clutches are controlled by the following steps: (a) at a time point when a speed change command is issued, feeding one of said plurality of speed change clutches to be subsequently brought into the engaged state with hydraulic oil; (b) at the time point when said speed change command is issued, calculating both output torque from said transmission just before speed change and output torque from said transmission immediately after speed change, respectively; (c) calculating a clutch hydraulic pressure to equalize said output torques; (d) sensing the termination of filling time with respect to said one of speed change clutches to be subsequently brought into the engaged state; and (e) causing said hydraulic pressure to decrease in the speed change clutch which is presently brought in the engaged state while exerting said calculating clutch hydraulic pressure on said one of speed change clutch to be subsequently brought into engaged state and thereafter causing said clutch hydraulic pressure to increase gradually on said speed change clutch.

Claim 7

A method of controlling a plurality of speed change clutches which are to be incorporated in a transmission of a vehicle, said method being adapted to be applied to said transmission, characterized in that said speed change clutches are controlled by the following steps: (a) at a time point when a speed change command is issued, applying hydraulic oil to one of said plurality of speed change clutches to be subsequently brought into the engaged state; (b) at the time point when said speed change command is issued, calculating both output torque from said transmission just before speed change and output torque from said transmission immediately after speed change, respectively; (c) calculating both a first clutch hydraulic pressure with respect to a speed change clutch which is presently brought in the engaged state and a second clutch hydraulic pressure with respect to one of said speed change clutches to be subsequently brought into the engaged state, respectively; (d) changing said hydraulic pressure in said speed change clutch which is presently brought in the engaged stage to an intensity of said first clutch hydraulic pressure; (e) sensing the termination of filling time with respect to one of said speed change clutches to be subsequently brought into the engaged state; and (f) causing said first hydraulic pressure to decrease on said speed change clutch which is presently brought in the engaged state while exerting said second clutch hydraulic pressure on one of said speed change clutches to be subsequently brought into the engaged state and thereafter causing said second clutch hydraulic pressure to increase gradually on one of said speed change clutches to be subsequently brought into the engaged state.

Claim 8

A method of controlling a plurality of speed change clutches which are to be incorporated in a transmission of a vehicle, said method being adapted to be applied to said transmission, characterized in that said speed change clutches are controlled by the following steps: (a) at a time point when a speed change command is issued, applying hydraulic oil to one of said plurality of speed change clutches to be subsequently brought into the engaged state; (b) at the time point when said speed change command is issued, calculating both output torque from said transmission just before speed change and output torque from said transmission immediately after speed change, respectively; (c) calculating both a first clutch hydraulic pressure with respect to a speed change clutch which is presently brought in the engaged state and a second clutch hydraulic pressure with respect to one of said speed change clutches to be subsequently brought into the engaged state, respectively; (d) changing said hydraulic pressure in said speed change clutch which is presently brought in the engaged stage to an intensity of said first clutch hydraulic pressure; (e) sensing the termination of filling time with respect to one of said speed change clutches to be subsequently brought into the engaged state; and (f) causing said first hydraulic pressure to decrease on said speed change clutch which is presently brought in the engaged state while exerting said second clutch hydraulic pressure on one of said speed change clutches to be subsequently brought into the engaged state and thereafter causing said second clutch hydraulic pressure to increase gradually on one of said speed change clutches to be subsequently brought into the engaged state.

Claim 9

A method of controlling a plurality of speed change clutches which are incorporated in a transmission as claimed in claims 1 or 5, characterized by controlling said hydraulic pressure exerted on each of said speed change clutches by means of an electronically controlled type pressure control valve which is hydraulically connected individually to each of said speed change clutches.

Claim 10

A method of controlling a plurality of speed change clutches which are incorporated in a transmission as claimed in claims 4 or 5, characterized by calculating output torque T B from the transmission as measured at the time point when said speed change command is issued in accordance with the following formula: T.sub.B =G·T.sub.t where G=gear ratio of the whole transmission T t =output torque from the torque converter.

Claim 11

A method of controlling a plurality of speed change clutches which are incorporated in a transmission as claimed in claims 4 or 5, characterized by calculating output torque T D from the transmission as measured at the starting time of speed change in accordance with the following formula: T.sub.A =G'·T.sub.c where G'=gear ratio between clutch to be engaged and transmission output shaft at the starting time of speed change T c =friction torque of clutch to be engaged at the starting time of speed change.