摘要:
The rotational speed of an engine Ne and a drum rotational speed Nt of a clutch Cl are compared against each other to determine a power on/off. For a 2.fwdarw.3 and a 2.fwdarw.4 shift in the power off condition, a timing solenoid SL5 is turned on (duty cycle of 100%) to accelerate the termination of a preceding speed range, thus increasing a time delay between such termination and the activation of a new speed range to be established. For other shifts, a time difference between the termination of a preceding speed range and the activation of a new speed range to be established is adjusted, by energizing the solenoid SL5 in accordance with the throttle opening .theta. and the vehicle speed No such that SL5 is energized with a high duty cycle for a longer .theta. and with a low duty cycle for a smaller .theta..
摘要:
An electronically controlled automatic transmission system including an automatic transmission having a plurality of clutches and brakes activated by application of a fluid pressure to change the gear ratio by engagement and disengagement of the clutches and brakes, a fluid pressure switching device for controlling the application of the fluid pressure to the clutches and brakes, and an electronic controller for changing the engagement and disengagement of the clutches and brakes by driving the fluid pressure switching device in accordance with the running condition of the vehicle, the electronic controller also controlling the speed of engagement of a clutch or brake which is to be engaged. The electronic controller includes a torque sensor for detecting the torque of the output shaft of the automatic transmission, and an engagement speed correcting device for correcting the speed of engagement of a clutch or brake which is to be engaged on the basis of the detected torque. If the condition of double engagement is judged to be improper in the process of gear-shifting, the speed of engagement of the clutch or brake to be engaged is automatically corrected so that the condition of double engagement is shifted to an optimal one by feedback control. Thus, the shock applied to the vehicle during a gear-shifting operation is reduced.
摘要:
A shifting arrangement of an overdrive position of a fourth gear is connected behind a shifting arrangement of a Simpson gear set of a first gear and/or a second gear. The connection transforms a conventional four-speed automatic transmission into a five-speed automatic transmission or a six-speed automatic transmission.
摘要:
In an automatic transmission, a double transition upshift to a target range requires the release of two off-going clutches and the engagement of two on-coming clutches. The shift is made in two stages. The first stage involves a first off-going clutch and a first on-coming clutch, and begins a shift to a third range having a speed ratio lower than the target range so that input speed is decreased and power is supplied throughout the shift. The speed decrease is managed by a closed-loop control of the first on-coming clutch until the clutch reaches a synchronous speed for the target range. The closed-loop control parameter is on-coming clutch slip speed which is controlled to a calculated slip speed profile. The profile has a first steep slope and a final less steep slope so that the actual slip can smoothly go to zero in a given time period. When near synchronous speed is reached, the second off-going clutch begins to release and at the end of the closed-loop control the second on-coming clutch is applied to complete the shift to the target range.
摘要:
A transmission control system for controlling a transmission. The system has a main transmission with a speed changing mechanism and an output shaft, a substransmission connected to the output shaft, and a control system for receiving outputs from a number of sensors which sense the running state of the vehicle. The control system itself has two outputs, there being two separate hydraulic controls connected to the two system outputs, respectively. The two hydraulic controls control the speed changing mechanisms of the main and subtransmissions, respectively. Also provided is a hydraulic pressure source which supplies a working fluid to the two hydraulic controls. The control system determines whether the main and subtransmissions are in a transient period of the speed changing operation and, as long as one of the two transmissions is in the transient period, inhibits the speed changing operation of the other transmission.
摘要:
In the control of a vehicle automatic transmission having a series connection of an overdrive gear mechanism and an underdrive gear mechanism, the overdrive gear being switched over between direct connection and overdrive both when the underdrive gear mechanism is switched to direct connection and to speed reduction, a maximum limit is set for the period over which the overdrive gear mechanism is switched to overdrive while the underdrive gear mechanism is switched to speed reduction, such a maximum period being determined according to a vehicle operational parameter such as vehicle speed, throttle opening or transmission fluid temperature.
摘要:
An automatic transmission control device is configured to execute a first shifting between a pre-shifting gear position and an intermediate gear position, and a second shifting between the intermediate gear position and a post-shifting gear position such that each of the first and second shiftings is executed by releasing one of engagement devices and engaging one of the engagement devices, and is configured, upon transition from the first shifting to the second transition, to gradually changing an engagement torque of an engagement-maintained engagement device as one of the engagement devices which is engaged upon completion of the first shifting and is maintained in the engaged state during the second shifting, such that the engagement torque of the engagement-maintained engagement device is changed gradually from a required engagement torque required upon completion of the first shifting, to a required engagement torque which is required in the second shifting.
摘要:
Torque shares that express an exchange of torque are set as a constraint condition of an equation of motion of an automatic transmission, so it is suitable to control an exchange of torque between engagement devices, which is difficult in shift control, and it is possible to solve the equation of motion. In other words, it is possible to handle any shift pattern with the use of a predetermined shift model. Furthermore, at the time of a shift in which two elements are released and two elements are engaged, a first shift and a second shift in each of which one element is released and one element is engaged are carried out, so three control operation amounts are used in each of the first shift and the second shift, with the result that it is possible to solve the equation of motion.
摘要:
A method of down-shifting a transmission avoids output shaft oscillations by briefly increasing the torque capacity of an off-going element at the end of the inertia phase. The torque capacity of the off-going element is then reduced to zero when the measured transmission speed ratio begins to decrease. The method is suitable for downshifts that involve multiple off-going elements and multiple on-coming elements such as a shift from tenth gear to sixth gear in a ten speed transmission.
摘要:
A method of operating of a drivetrain, having at least a drive motor and an automatic transmission with at least five shift elements, to improve a shift speed such that during a first upshift or a first downshift, at least one required shift element is prepared such that, when a synchronization point is reached, the successive upshift or the successive downshift can be immediately carried out. The method comprises the steps of requiring, at most, two of the at least five shift elements be disengaged and a remainder of the shift elements be disengaged for each gear for transferring one of torque and force; and one of increasing and decreasing a torque of the drive motor, relative to a torque of the drive motor derived from a driver's wish, during one of the first upshift or downshift and the successive upshift or downshift to assist with an overlapped implementation of the successive upshifts or the successive downshifts.