摘要:
A shift control device is provided with a structure wherein when a driver selects a manual shift mode, an appropriate shift level is set as an initial shift level in conformity to a driver's will to have or not to have a drive-force source braking effect. When a shift lever 72 is operatively moved to an S-position to select an S-mode, depending on whether a stay time in a position “D” continuing for a certain time period or more (step S2), a shift mode switching or a manual shift mode direct-selecting is determined, and then an initial shift level is individually determined for a shift mode switching (YES in step S2) and a manual shift mode direct-selecting (NO in step S2). This determines appropriate initial shift level in conformity to the driver's will to have the drive-force source braking effect in the shift mode switching and that not to have the drive-force source braking effect in the manual shift mode direct-selecting.
摘要:
A shift control device of a vehicular automatic transmission that establishes a plurality of gear steps of different speed change ratios by selectively engaging a plurality of friction engagement devices ends the shift control by making an engagement end determination regarding an engagement-side friction engagement device if it has been determined continuously for a predetermined time that the input shaft rotation speed of the automatic transmission is in the vicinity of the synchronous rotation speed of the post-shift gear step. The predetermined time is set at a first time if the downshift is a power-on downshift due to a shift judgement in a power-on state, and is set at a second time that is shorter than the first time if the downshift is a power-off→on downshift selected in connection with a change to the power-on state during a power-off shift due to the shift judgment in a power-off state.
摘要:
The invention relates to a shift control apparatus for an automatic transmission, that executes a torque reduction control when the transmission executes a second downshift in response to a second downshift determination made during first downshift. The shift control apparatus includes a multiple shift execution unit that starts the second downshift operation in response to the second downshift determination, and a torque reduction control execution unit that executes a torque reduction control when the rotational speed of the input member is increased to at least a predetermined first determination speed, which is determined in accordance with a shift ratio of a gear stage after the second downshift operation, after the second downshift starts. This allows the rotational speed of the input shaft to be quickly changed to the appropriate synchronous rotational speed. Thus, the desired driving force is provided upon completion of the second downshift without overspeeding the engine.
摘要:
A diagnostic system for an automatic transmission is provided in which a microcomputer determines that torque that can drive the driving wheels of the vehicle is not transmitted to an output shaft of the automatic transmission when the vehicle is stopped and the ignition key is operated to the OFF position, and performs forced energization of solenoids of solenoid valves associated with respective friction devices of the transmission, while monitoring current passing through the solenoid valves. If the current monitored does not match the current for energizing any of the solenoids, the microcomputer determines that the corresponding solenoid valve is at fault. Thus, the diagnostic system appropriately determines the presence of a fault of each solenoid valve for controlling the hydraulic pressure to each friction device, with increased flexibility and freedom.
摘要:
When a downshift instruction has been detected, the oil pressure of a lookup clutch is controlled, and the state of operation of the automatic transmission is detected. If a starting condition has been met, a slip rotation speed of the lockup clutch is calculated, and if the calculated slip rotation speed is greater than or equal to a reference rotation speed, the calculated slip rotation speed is set as a target slip rotation speed. If a condition for converging the target slip rotation speed has been met, the target slip rotation speed is then converged to a steady target rotation speed.
摘要:
An ECU executes a program that includes the steps of setting an abnormality flag when a hydraulic pressure switch is on even though a lock-up clutch is in a lock-up OFF state, forcing an SLU off when the lock-up clutch is on and the abnormality flag is on, determining that there is an SLU failure when the lock-up clutch is still in a lock-up ON state after a predetermined period of time has passed, and determining that there is a hydraulic pressure switch failure when the lock-up clutch is not in the lock-up ON state after the predetermined period of time has passed.
摘要:
In a shift control device and a shift control method of an automatic transmission that establishes a plurality of gear steps of different speed change ratios by selectively engaging a plurality of friction engagement devices, one of a shift start time point and an inertia phase start time point is used as a reference time. In a power-off shift, the shift action is compulsorily ended when the elapsed time from the reference time exceeds a first time. In a power-on shift, the shift action is compulsorily ended when the elapsed time from the reference time exceeds a second time that is set shorter than the first time. If a switch from the power-off shift to the power-on shift occurs halfway through the power-off shift, the shift action is compulsorily ended when the elapsed time from the time point of the switch exceeds a predetermined time.
摘要:
The invention relates to a shift control apparatus for an automatic transmission that executes a torque reduction control when the transmission downshifts in response to a downshift determination made during an upshift. The shift control apparatus includes a multiple shift execution unit that starts the downshift in response to the downshift determination, and a torque reduction control execution unit that determines whether the rotational speed of the input member is at least a control start-up rotational speed, after the downshift operation starts, and executes a torque reduction control of the power source when the rotational speed of the input member is increased to at least the control start-up rotational speed. This allows the rotational speed of the input shaft to be quickly changed to the appropriate synchronous rotational speed. Thus, the desired driving force is provided upon completion of the downshift without overspeeding the engine.
摘要:
A shift control apparatus for a vehicular automatic transmission provided with a fuel cut apparatus which cuts off fuel supplied to an engine when an engine speed exceeds a predetermined value during deceleration of a vehicle, and an automatic transmission in which a gearshift is achieved with a clutch-to-clutch downshift in which a hydraulic friction device to be released is released and a hydraulic friction device to be applied is applied, further includes a controller. The controller corrects, through learning control, an apply pressure of at least one of the hydraulic friction devices to be operated for the clutch-to-clutch downshift such that an amount of drop in a rotational speed of an input shaft of the automatic transmission increases when that amount of drop is less than a predetermined value during the clutch-to-clutch downshift.
摘要:
When it has been determined that control for a predetermined upshift has been started while an accelerator pedal was not being depressed, and that a factor that changes an input torque of an automatic transmission has been generated, an engaging pressure of a predetermined hydraulic frictional engagement device is corrected by a correction amount in accordance with the factor that changes the input torque. As a result, undershooting of an engine speed, as well as shift shock which results from that undershooting, is able to be preferably suppressed.