US 5,573,473 A · Apparatus and method for controlling lock-up clutch

A controller for a speed changing device which receives an engine output through a torque converter and which includes a transmission having a plurality of speed changing clutches for selecting speed stages, a lock-up clutch for directly connecting the engine output to the transmission, and solenoid controlled valves each being connected to the lock-up clutch and the plurality of speed changing clutches respectively, and which releases the lock-up clutch at the time of speed changing, each of the plurality of speed changing clutches being provided with filling completion detecting means for detecting completion of filling of the speed changing clutch, the controller comprising:

first control means for issuing, at the time when a speed changing command is issued, an electric command to a solenoid controlled valve of a speed changing clutch to be engaged next so as to start the supply of oil, and
second control means, when the completion of filling of the speed changing clutch to be engaged next is detected based on a detection result of the filling completion detection means, for turning off the solenoid controlled valve relative to the lock-up clutch at the time of detection of the completion of filling, raising up a hydraulic pressure of the speed changing clutch to be engaged next to a predetermined pressure at the time of detection of the completion of filling, starting a hydraulic pressure gradual increase control of the raised up hydraulic pressure, and issuing an electric command for turning off the solenoid controlled valve of the speed changing clutch being currently engaged at the time of detection of the completion of filling.

A method of controlling a lock-up clutch wherein the lock-up clutch is connected directly to an input shaft and an output shaft of a torque converter disposed between an engine and a transmission including a plurality of speed changing clutches, a piston back pressure part of the lock-up clutch being exerted with an inner pressure of the torque converter, the lock-up clutch being provided with a pressure control valve adapted to be actuated in response to an electric command, the pressure control valve being controlled in the following manner:

(a) After a speed changing start command is input and filling of a speed changing clutch to be engaged next is completed, a lock-up clutch hydraulic pressure is lowered to a predetermined value which is slightly greater than the inner pressure of the torque converter at the time of completion of filling, a speed changing stage and a throttle amount are detected, an interval time corresponding to the detected speed changing stage and the detected throttle amount is read out from a memory table in which optimum interval times are stored in association with each value of the speed changing stages and the throttle amounts, and a time counting is started;
(b) Thereafter, until the counted time coincides with the interval time read out from the memory table, the lock-up clutch hydraulic pressure is maintained at the predetermined value;
(c) Gradual increase of the lock-up clutch hydraulic pressure is started at the time when the counted time coincides with the interval time read out from the memory table, and subsequently the gradual increase of the hydraulic pressure is stopped at the time when an e value (torque converter output shaft revolution number/torque converter input shaft revolution number) of the torque converter reached a predetermined value around one;
and
(d) After the e value of the torque converter reached the predetermined value, an engine output torque is successively calculated, and if the engine revolution number is greater than a predetermined lock-up minimum revolution number, control is made so that the lock-up clutch hydraulic pressure becomes the calculated value of the engine output torque or a hydraulic pressure value corresponding to a value slightly greater than the calculated value of the engine output torque.

2 more elements

A method of controlling a lock-up clutch wherein the lock-up clutch is connected directly to an input shaft and an output shaft of a torque converter disposed between an engine and a transmission including a plurality of speed changing clutches, a piton back pressure part of the lock-up clutch being exerted with an inner pressure of the torque converter, the lock-up clutch being provided with a pressure control valve adapted to be actuated in response to an electric command, the pressure control valve being controlled in the following manner:

(a) After a speed changing start command is input and filling of a speed changing clutch to be engaged next is completed, a lock-up clutch hydraulic pressure is lowered to a predetermined value which is slightly greater than the inner pressure of the torque converter at the time of completion of filling, a speed changing stage and a throttle amount are detected, an interval time corresponding to the detected speed changing stage and the detected throttle amount is read out from a memory table in which optimum interval times are stored in association with each value of the speed changing stages and the throttle amounts, and a time counting is started;
(b) Thereafter, until the counted time coincides with the interval time read out from the memory table, the lock-up clutch hydraulic pressure is maintained at the predetermined value;
(c) Gradual increase of the lock-up clutch hydraulic pressure is started at the time when the counted time coincided with the interval time read out from the memory table, and subsequently the gradual increase of the hydraulic pressure is stopped at the time when a predetermined set time elapsed from the start of the gradual increase of the hydraulic pressure;
and
(d) After the gradual increase of the hydraulic pressure is stopped, an engine output torque is successively calculated, and if the engine revolution number is greater than a predetermined lock-up minimum revolution number, control is made so that the lock-up clutch hydraulic pressure becomes the calculated value of the engine output torque or a hydraulic pressure value corresponding to a value slightly greater than the calculated value of the engine output torque.

2 more elements

A method of controlling a lock-up clutch wherein the lock-up clutch is connected directly to an input shaft and an output shaft of a torque converter disposed between an engine and a transmission including a plurality of speed changing clutches, a piston back pressure part of the lock-up clutch being exerted with an inner pressure of the torque converter, the lock-up clutch being provided with a pressure control valve adapted to be actuated in response to an electric command, the pressure control valve being controlled in the following manner:

(a) After a speed changing start command is input and filling of a speed changing clutch to be engaged next is completed, a lock-up clutch hydraulic pressure is lowered to a predetermined value which is slightly greater than the inner pressure of the torque converter at the time of completion of filling;
(b) Thereafter, until a relative revolution number of the input and output shafts of the transmission becomes zero or a value around zero, the lock-up clutch hydraulic pressure is maintained to the predetermined value;
(c) Gradual increase of the lock-up clutch hydraulic pressure is started at the time when the relative revolution number of the input and output shafts of the transmission became zero or the value around zero, and subsequently the gradual increase of the hydraulic pressure is stopped at the time when an e value (torque converter output shaft revolution number/torque converter input shaft revolution number) of the torque converter reached a predetermined value around one;
and
(d) After the e value of the torque converter reached the predetermined value, an engine output torque is successively calculated, and if the engine revolution number is greater than a predetermined lock-up minimum revolution number, control is made so that the lock-up clutch hydraulic pressure becomes the calculated value of the engine output torque or a hydraulic pressure value corresponding to a value slightly greater than the calculated value of the engine output torque.

2 more elements

A method of controlling a lock-up clutch wherein the lock-up clutch is connected directly to an input shaft and an output shaft of a torque converter disposed between an engine and a transmission including a plurality of speed changing clutches, a piston back pressure part of the lock-up clutch being exerted with an inner pressure of the torque converter, the lock-up clutch being provided with a pressure control valve adapted to be actuated in response to an electric command, the pressure control valve being controlled in the following manner:

(a) After a speed changing start command is input and filling of a speed changing clutch to be engaged next is completed, a lock-up clutch hydraulic pressure is lowered to a predetermined value which is slightly greater than the inner pressure of the torque converter at the time of completion of filling;
(b) Thereafter, until an e value (torque converter output shaft revolution number/torque converter input shaft revolution number) of the torque converter reaches a first predetermined value, the lock-up clutch hydraulic pressure is maintained at the predetermined value;
(c) Gradual increase of the lock-up clutch hydraulic pressure is started at the time when the e value of the torque converter reached the first predetermined value, and subsequently the gradual increase of the hydraulic pressure is stopped at the time when the e value of the torque converter reached a second predetermined value around one;
and
(d) After the e value of the torque converter reached the second predetermined value, an engine output torque is successively calculated, and if the engine revolution number is greater than a predetermined lock-up minimum revolution number, control is made so that the lock-up clutch hydraulic pressure becomes the calculated value of the engine output torque or a hydraulic pressure value corresponding t a value slightly greater than the calculated value of the engine output torque.

2 more elements

A method of controlling a lock-up clutch wherein the lock-up clutch is connected directly to an input shaft and an output shaft of a torque converter disposed between an engine and a transmission including a plurality of speed changing clutches, a piston back pressure part of the lock-up clutch being exerted with an inner pressure of the torque converter, the lock-up clutch being provided with a pressure control valve adapted to be actuated in response to an electric command, the pressure control valve being controlled in the following manner:

(a) When a start command is input and an engine revolution number increases more than a predetermined lock-up minimum revolution number, a lock-up clutch hydraulic pressure is lowered to a predetermined value which is slightly greater than the inner pressure of the torque converter after keeping the lock-up clutch hydraulic pressure in a high pressure state for a predetermined period of time, and thereafter, until the completion of filling of the lock-up clutch is detected, the lock-up clutch hydraulic pressure is maintained at the predetermined value;
(b) When the completion of filling of the lock-up clutch is detected, the lock-up clutch hydraulic pressure is gradually increased at this time point, and subsequently the gradual increase of the hydraulic pressure is stopped at the time when an e value (torque converter output shaft revolution number/torque converter input shaft revolution number) of the torque converter reached a predetermined value around one;
and
(c) After the e value of the torque converter reached the predetermined value, an engine output torque is successively calculated, and if the engine revolution number is greater than the predetermined lock-up minimum revolution number, control is made so that the lock-up clutch hydraulic pressure becomes the calculated value of the engine output torque or a hydraulic pressure value corresponding to a value slightly greater than the calculated value of the engine output torque.

1 more element

Apparatus and method for controlling lock-up clutch

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Apparatus and method for controlling lock-up clutch

Life of this patent

Abstract

Claims15