Torque Converters
This component allows you to define a torque converter in the driveline model.
Learn about torque converters:
Creating or Modifying Torque Converters
To create or modify torque converters:
1. From the Driveline Components menu, point to Torque Converter, and then select New/Modify.
3. Select OK.
About Torque Converters
You define torque converters using three parts:
■Impeller (input shaft)
■Turbine (output shaft)
■Case
On these three parts, you apply (at least) three different forces:
■Impeller drag
■Turbine torque
■Converter damping
■Lockup clutch torque (optional)
These forces are defined according to the content of the property file you specify.
The property file stores two curves:
■Torque ratio versus speed ratio
■Capacity factor versus speed ratio
Capacity factor is defined as input speed divided by the square root of the input torque, as a function of speed ratio. The units are angular_velocity/SQRT(torque), where the units of angular_velocity and torque are defined in the property file.
The following figures show sample plots for these two curves.
Torque Ratio
Capacity Factor
The torque converter includes a clutch part that is connected to the turbine with a torsion spring. The clutch allows the direct engagement of the impeller to the turbine when the torque converter change-over point is reached. You can define the clutch expression by either specifying the change-over point (the speed ratio at which the clutch must be engaged) or a clutch expression as a function of time.
Adams Driveline uses the following formulas to evaluate action and reaction torque:
Impeller drag (acting between impeller and turbine):
direction * STEP5(speed_ratio,0.995,1,1.005,-1) * (1/ucf_angle_to_radians*WZ(I,J,J) / Capacity_factor)**2
Turbine torque (acting between turbine and case):
direction * - impeller_drag * AKISPL(speed_ratio,0, torque_ratio,0)
Converter damping (acting between turbine and clutch part):
-clutch_torsional_stiffness*AZ(I,J) - clutch_torsional_damping*WZ(I,J,J)
Lockup clutch (acting between impeller and clutch part) torque:
clutch switch * clutch torque
Speed ratio (ratio of the turbine speed over impeller speed):
turbine_speed / STEP5(ABS(impeller_speed),0,1,1,impeller_speed)
You can define the clutch torque either as a user-entered function of time or as a change-over point. For the case of a change-over point, the clutch torque function will be:
STEP5(speed_ratio, change_over_point - .05, 0, change_over_point + .05, -clutch_slip_gain * WZ(I,J,J))
In the Standard Interface, you can vary the property file, direction, and lockup clutch actuation method.
Request Definition
Result name: torque_cvtr_results
Component name: | Component units: | Definition: |
|---|---|---|
impeller_rpm | RPM | Angular velocity of the impeller (input shaft) with respect to the torque converter case. |
turbine_rpm | RPM | Angular velocity of the turbine (output shaft) with respect to the torque converter case. |
conv_clutch_rpm | RPM | Angular velocity of the clutch (output shaft) with respect to the turbine. |
speed_ratio | no units | The ratio of the turbine speed over impeller speed. |
impeller_torque | torque | Torque on the impeller (input shaft) with respect to the torque converter case. |
turbine_torque | torque | Torque on the turbine (output shaft) with respect to the torque converter case. |
conv_clutch_torque | torque | Torque on the clutch (output shaft) with respect to the turbine. |
K_factor | angular velocity / SQRT(torque) | The torque converter capacity factor. |
torque_ratio | no units | The ratio of the turbine torque over impeller torque. |
Subsystem Parameters
Property file (<db_name>/torque_converters.tbl)
Example Torque-Converter Property File
<adriveline_shared>/torque_converters.tbl/mdi_0001.tcf
$----------------------------------------------------------MDI_HEADER
[MDI_HEADER]
FILE_TYPE = 'tcf'
FILE_VERSION = 4.0
FILE_FORMAT = 'ASCII'
$---------------------------------------------------------------UNITS
[UNITS]
LENGTH = 'foot'
FORCE = 'pound_force'
ANGLE = 'deg'
MASS = 'pound_mass'
TIME = 'sec'
$---------------------------------------------TORQUE_CONVERTER_HEADER
[TORQUE_CONVERTER_HEADER]
MODEL = 'torque_ratio_capacity_factor'
CLUTCH_ACTIVE = 'yes'
$--------------------------------------------------------------CLUTCH
[CLUTCH]
$ clutch mass & inertia properties
MASS = 2.2
IXX = 1
IYY = 1
IZZ = 2
$ clutch connection properties
$ to turbine:
CLUTCH_TORSIONAL_STIFFNESS = 18
CLUTCH_TORSIONAL_DAMPING = 18
$ to impeller:
CHANGE_OVER_POINT = 0.8
CLUTCH_SLIP_GAIN = 0.6
$--------------------------------------------------------TORQUE_RATIO
[TORQUE_RATIO]
{speed_ratio torque_ratio}
-5.000 1.769
-2.000 1.769
-1.000 1.769
0.000 1.769
0.123 1.674
0.251 1.573
0.382 1.457
0.509 1.348
0.636 1.241
0.736 1.159
0.809 1.094
0.868 1.038
0.895 1.012
0.903 1.009
0.908 1.009
0.914 1.009
0.918 1.009
0.922 1.009
0.926 1.009
0.930 1.009
0.934 1.009
0.937 1.007
0.940 1.007
0.943 1.007
0.945 1.007
0.948 1.007
0.950 1.007
0.953 1.006
0.955 1.006
0.957 1.004
0.959 1.004
0.961 1.004
0.963 1.004
0.965 1.004
0.996 1.004
0.997 1.004
0.998 1.004
1.001 1.130
1.006 1.120
1.013 1.058
1.019 1.040
1.020 1.030
1.025 1.025
1.032 1.021
1.052 1.015
1.100 1.012
1.208 1.010
1.258 1.009
1.328 1.006
1.423 1.005
1.592 1.006
1.808 1.004
2.166 1.005
2.833 1.006
4.172 1.005
8.283 1.005
$-----------------------------------------------------CAPACITY_FACTOR
[CAPACITY_FACTOR]
{speed_ratio capacity_factor}
-5.000 956.4
-2.000 956.4
-1.000 956.4
0.000 956.4
0.123 945.6
0.251 935.4
0.382 927.0
0.509 928.8
0.636 931.8
0.736 967.2
0.809 1026.0
0.868 1093.2
0.895 1127.4
0.903 1183.2
0.908 1241.4
0.914 1300.2
0.918 1359.0
0.922 1417.2
0.926 1475.4
0.930 1533.0
0.934 1591.2
0.937 1650.0
0.940 1707.6
0.943 1766.4
0.945 1824.6
0.948 1882.8
0.950 1940.4
0.953 1996.8
0.955 2054.4
0.957 2112.6
0.959 2170.8
0.961 2229.0
0.963 2285.4
0.965 2343.6
0.996 7432.8
0.997 30000.0
0.998 210000.0
1.001 210000.0
1.006 7407.0
1.013 5301.0
1.019 4350.0
1.020 3771.6
1.025 3411.0
1.032 3050.4
1.052 2674.2
1.100 2325.6
1.208 2056.8
1.258 1929.6
1.328 1812.6
1.423 1697.4
1.592 1624.2
1.808 1534.8
2.166 1467.6
2.833 1444.8
4.172 1422.6
8.283 1413.0