Shift control system for vehicle
A shift control system which can reduce a shift shock is provided. A target torque determiner set a target torque of an engine based on an accelerator position. An actual torque determiner calculates an actual torque of the engine in the inertia phase. A controller calculates an integrated value of a difference between the target torque and the actual torque from a commencement of the inertia phase to a predetermined time point before a termination of the inertia phase, and corrects the target torque in a remaining period between the predetermined time point and the termination of the inertia phase.
1. A shift control system that is applied to a vehicle including a geared automatic transmission connected to an output side of an engine in which a gear stage is shifted among a plurality of stages by manipulating a plurality of engagement devices, comprising:
a controller that controls an output torque of the engine during shifting operation of the gear stage of the transmission,
wherein the controller is configured to
set a target torque of an output torque of the engine in an inertia phase in which an input speed of the transmission is changed by a shifting operation of the gear stage toward a synchronous speed to be achieved in the gear stage to be established after the shifting operation,
calculate an actual torque of the engine in the inertia phase,
perform a feedback control of the actual torque based on a difference between the target torque and the actual torque,
calculate an integrated value of the difference between the target torque and the actual torque from a commencement of the inertia phase to a predetermined time point before a termination of the inertia phase, and
correct the target torque in a remaining period between the predetermined time point and the termination of the inertia phase based on the integrated value in such a manner that the input speed is changed toward the synchronous speed.
2. The shift control system according to claim 1 , wherein the controller is further configured to:
divide the remaining period into predetermined units of time; and
calculate a correction amount for correcting the target torque for each unit of time by dividing the integrated value by the units of time.
3. The shift control system according to claim 2 , wherein the controller is further configured to correct the correction amount using a weighting coefficient determined in accordance with a degree of progress of the shifting operation.
4. The shift control system according to claim 3 , wherein the controller is further configured to correct the correction amount in an initial phase of the inertia phase using the weighting coefficient that is larger than the weighting coefficient used in the later phase of the inertia phase.
5. The shift control system according to claim 2 , wherein the controller is further configured to calculate the correction amount for each correction period in the inertia phase.
6. The shift control system according to claim 1 , wherein the controller is further configured to limit the integrated value so as to inhibit the corrected target torque to be reduced lower than a misfire limit torque obtained based on an operating state of the engine.
7. The shift control system according to claim 1 , wherein the controller is further configured to stop fuel supply to the engine when the target torque corrected by the integrated value falls below a minimum torque of the engine.