Method of and apparatus for speed change control
First Claim
1. A speed change control method for engaging and disengaging a plurality of clutches of a transmission of a vehicle to change a gear ratio of the transmission so as to change a rotational speed of an output shaft of the transmission and for effecting a shift between forward travel and reverse travel of said vehicle, said method comprising the steps of:
- storing braking data representing braking forces which are predetermined for particular rotational speeds of said output shaft;
storing deceleration/acceleration data representing a target deceleration/acceleration curve wherein a torque of said output shaft changes smoothly with time;
providing a signal directing a shify between forward travel and reverse travel of said vehicle;
detecting the rotational speed of said output shaft when said signal is provided;
selecting from the thus stored braking data a braking force in accordance with the thus detected rotational speed of said output shaft;
applying, in response to a providing of said signal directing a shift between forward travel and reverse travel, the thus selected braking force to said output shaft to effect a braking torque on said output shaft;
engaging a predetermined clutch among said plurality of clutches in response to a providing of said signal directing a shift between forward travel and reverse travel;
increasing the thus applied braking force until a speed of said vehicle is reduced to a predetermined value, andthen gradually decreasing the thus applied braking force to zero while gradually increasing an engagement of said predetermined clutch so as to cause a deceleration/acceleration of the vehicle given through said output shaft to smoothly change along said target deceleration/acceleration curve to thereby decrease shock to the vehicle upon a completion of the engagement of said predetermined clutch.
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Accused Products
Abstract
The thermal load on a transmission clutch, which is generated when a shift between forward and reverse is made, can be reduced and a shock from a speed change can be eliminated. To these ends, as soon as a speed change signal is received (step 150), an all clutch control system (ACC) is actuated to set a target acceleration in terms of the amount of control (steps 152, 154). Then, it is determined whether the speed change involves a shift between forward and reverse (FR speed change) (step 156). If the speed change is found to be the FR speed change, then it is further determined whether the vehicle speed V is larger than a reference value VO (step 158); if the vehicle speed is larger than the reference value, then the oil pressure for operating a steering brake is read from preestablished map data (step 160), and the steering brake is operated by the oil pressure which has been read (steps 162, 164). After that, the ACC control program goes back to step 156. If the speed change is found to be a non-FR speed change or a FR speed change wherein V≦VO, then the hydraulic gradient of a load clutch of the transmission is determined by a fuzzy reasoning (step 168), then clutch oil pressure PC based on the hydraulic gradient is determined to control the engaging force of the load clutch (steps 172, 174).
33 Citations
16 Claims
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1. A speed change control method for engaging and disengaging a plurality of clutches of a transmission of a vehicle to change a gear ratio of the transmission so as to change a rotational speed of an output shaft of the transmission and for effecting a shift between forward travel and reverse travel of said vehicle, said method comprising the steps of:
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storing braking data representing braking forces which are predetermined for particular rotational speeds of said output shaft; storing deceleration/acceleration data representing a target deceleration/acceleration curve wherein a torque of said output shaft changes smoothly with time; providing a signal directing a shify between forward travel and reverse travel of said vehicle; detecting the rotational speed of said output shaft when said signal is provided; selecting from the thus stored braking data a braking force in accordance with the thus detected rotational speed of said output shaft; applying, in response to a providing of said signal directing a shift between forward travel and reverse travel, the thus selected braking force to said output shaft to effect a braking torque on said output shaft; engaging a predetermined clutch among said plurality of clutches in response to a providing of said signal directing a shift between forward travel and reverse travel; increasing the thus applied braking force until a speed of said vehicle is reduced to a predetermined value, and then gradually decreasing the thus applied braking force to zero while gradually increasing an engagement of said predetermined clutch so as to cause a deceleration/acceleration of the vehicle given through said output shaft to smoothly change along said target deceleration/acceleration curve to thereby decrease shock to the vehicle upon a completion of the engagement of said predetermined clutch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A speed change control apparatus comprising:
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a transmission equipped with a plurality of speed change gears, a clutch for selecting a combination of the gears to be meshed with each other, and an output shaft; a clutch driving section for operating the clutch of the transmission; a steering brake for applying a braking force to the output shaft of said transmission; a brake driving section for operating the steering brake; a revolution sensor for detecting the rotational speed of the output shaft of said transmission; and a speed change controller for storing braking data representing braking forces which are predetermined for particular rotational speeds of said output shaft, for storing deceleration/acceleration data representing a target deceleration/acceleration curve wherein a torque of said output shaft changes smoothly with time, for determining a vehicle deceleration/acceleration from said output shaft of said transmission in accordance with an output signal received from said revolution sensor, for selecting from the thus stored braking data a braking force in accordance with the thus detected rotational speed of the output shaft, and for causing said vehicle deceleration/acceleration to smoothly change along said target deceleration/acceleration curve by issuing a control signal to said clutch driving section and said brake driving section when a shift between forward and reverse in the vehicle is made. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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Specification