Shifting control method for hybrid vehicles
The present disclosure provides a shifting control method for hybrid vehicles to reduce the occurrence of a clutch releasing phenomenon due to an excessive change in input torque of a transmission during shifting of the vehicle, including: an entering step of performing, by a controller, a control to enter a torque hand over control in response to power off down shifting; and a rising control step of controlling, by the controller, an engagement side clutch torque to rise to correspond to a changed input torque of a transmission when a change rate in input torque of the transmission is equal to or more than a reference value during the torque hand over process.
1. A shifting control method for hybrid vehicles, the method comprising:
performing an entering step, by a controller, wherein a torque hand over control is entered in response to a power off down shifting; and
performing a rising control step, by the controller, wherein an engagement side clutch torque is increased to correspond to a changed input torque of a transmission when a change rate in an input torque of the transmission is equal to or greater than a reference value during the torque hand over control.
2. The shifting control method for hybrid vehicles of claim 1 , wherein the rising control step includes:
a first calculating step wherein a first target engagement side clutch torque is calculated from a control start time when the change rate of the input torque of the transmission rises to be equal to or greater than the reference value to a control end time when the torque hand over control ends, and the first target engagement side clutch torque is calculated by incrementing a clutch torque calculated by reflecting the input torque of the transmission up to the control end time from a target hold engagement side clutch torque calculated by reflecting the input torque of the transmission based on the control start time;
a second calculating step wherein a second target engagement side clutch torque is calculated from the control start time when the change rate of the input torque of the transmission rises to be equal to or greater than the reference value to the control end time when the torque hand over control ends, and incrementing and calculating the second target engagement side clutch torque until an engagement side clutch torque based on the control start time reaches the target hold engagement side clutch torque; and
a third calculating step wherein a third target engagement side clutch torque is calculated by summing the first target engagement side clutch torque calculated in the first calculating step and the second target engagement side clutch torque calculated in the second calculating step.
3. The shifting control method for hybrid vehicles of claim 2 , wherein in the first calculating step, the first target engagement side clutch torque is calculated by the following Equation:
the
first
target
engagement
side
clutch
torque
=
(
Apply
Clutch
Target
(
*
*
)
-
Apply
Clutch
Target
Hold
)
=
{
(
Input
torque
of
transmission
+
factor
*
(
Je
(
0
other
than
when
engine
clutch
is
attached
)
+
Jm
)
*
dNm
/
dt
)
}
-
Apply
Clutch
Target
Hold
)
;
wherein Apply Clutch Target(**) is a target engagement side clutch torque calculated by reflecting a current input torque of the transmission;
Apply Clutch Target Hold is a fixed value target hold engagement side clutch torque calculated by reflecting the input torque of transmission at the control start time;
Je is an engine rotation inertia;
Jm is a motor rotation inertia;
dNm/dt is a motor angular acceleration; and
factor is a constant.
4. The shifting control method for hybrid vehicles of claim 3 , wherein in the second calculating step, the second target engagement side clutch torque is calculated by the following Equation:
the
second
target
engagement
side
clutch
torque
=
Apply
Clutch
Torque
(
t
-
1
)
value
Hold
+
New
Auto
Ramp
to
Target
(
*
**
)
=
Apply
Clutch
Torque
(
t
-
1
)
value
Hold
+
{
(
Apply
Clutch
Target
Hold
-
Apply
Clutch
Torque
(
t
-
1
)
value
Hold
)
-
New
Auto
Ramp
to
Target
(
t
-
1
)
/
(
Torque
Phase
Target
Time
-
Phase
duration
time
)
;
wherein Apply Clutch Torque(t−1) value Hold is a fixed value hold engagement side clutch torque before the control start time;
New Auto Ramp to Target(***) is an engagement side clutch torque until the engagement side clutch torque based on the control start time reaches the target hold engagement side clutch torque;
New Auto Ramp to Target(t−1) is an engagement side clutch torque increment value per one cycle until the engagement side clutch torque before the control start time reaches the target hold engagement side clutch torque;
Torque Phase Target Time is a torque hand over control target time; and
Phase duration time is a torque hand over control elapsed time.
5. The shifting control method for hybrid vehicles of claim 2 , further comprising:
performing a control end determining step after the rising control step, wherein it is determined whether a torque hand over elapsed time reaches a torque hand over target time.