Automatic Transmission Modeling for Shift Quality using Adams/Driveline

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Solomon Jordan
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Liu Ford Motor Company Livonia, Michigan (734) 523-5484 Abstract: This paper

1 Automatic Transmission Modeling for Shift Quality using Adams/Driveline Paul Erlandson & Jack S. P. Liu Ford Motor Company Livonia, Michigan (734) Abstract: This paper introduces the use of Adams/Driveline to create a more streamlined approach to full-vehicle modeling for shift quality and transient NVH.

2 Presentation Outline Why Adams/Driveline for Automatic Transmission? Key Adams/Driveline Features Typical Adams/Driveline Automatic Transmission Model Exporting to Adams/Chassis Sample analysis for shift quality Conclusions 2

3 Why Adams/Driveline? Template-based. Seamless integration of transmission and driveline models. Quicker time to integrate trans/driveline assembly with vehicle model (compared to previous A/View-based method). Re-integration is sometimes necessary! Bottom line: Turnaround time to produce integrated Vehicle/Transmission model is reduced by > 70%! 3

4 Key A/Driveline Features Conceptual Wet Clutch Torque Converter Planetary Gearset Ravigneaux Gearset 4

5 Conceptual Wet Clutch Allows relative slip when torque capacity is exceeded. Locks when torque demand is less than torque capacity. Torque capacity is calculated from parameters in the clutch property file. Open clutch drag can be modeled. Timing of clutch element is handled via spline data in the clutch property file. 5

6 Conceptual Wet Clutch Clutch Torque (SFORCE) T ( t) = F ( t) µ ( s) R N sgn(s) Clamping force: Fc ( t) = Fp ( t) F Piston force: p F ( t) = P ( t) A = p Spring preload: F s = Ps A Effective radius: R c m = R o a c + 2 R i s a m ( t) π D 4 c 2 p F p sgn(s) d D R i R o s 6

7 Conceptual Wet Clutch (property file) $ CLUTCH_DATA [CLUTCH_DATA] N_OF_SURFACE = 10 (Nc) EFFECTIVE_RADIUS = (Rm) PRESSURE_AREA = (A) TURNING_POINT_PRESSURE = 0.0 (Ps) CLUTCH_MU = 0.11 (µ) OPEN_CLUTCH_DRAG_GAIN_FACTOR=0 TIME_OFFSET = 0 $ CLUTCH_PRESSURE [CLUTCH_PRESSURE] { time pressure} Pressure (p si) Clutch Pressure Spline (Pa) Time (sec) 7

8 Torque Converter Models torque multiplication of the converter. Relates turbine speed and torque to impeller speed and torque. Uses standard converter performance tables, stored in the property file. Lockup Clutch Modeling. 8

9 Torque Converter Engine Torque (SFORCE) T (t) i FUNCTION = AKISPL (time, 0, id) Torque Converter: Impeller Drag (Impeller-Turbine) N i(t) 2 = ( ) STEP ( Sr,0.99,1,1.01, 1) K (s ) i r STEP( Sr,0.99,1,1.01, 1) 1 s r Turbine Torque (Turbine - Case) T o ( t) = ( r ( s ) 1) T ( t) t r i N i (t) = engine rpm K i (s r ) = capacity factor (K-curve) r t (s r ) = torque ratio curve 9

10 Torque Converter STEP(s r, s 1-,0, s 1+,1) Lockup Clutch (SFORCE) 1 T p (t) = T p (t) sgn(s) STEP(s r, s 1-,0, s 1+,1) 0 s 1 s r Spring-damper Assembly (SFORCE) T d = K θ C θ sgn(s) s -1 10

11 Torque Converter (property file) $ TORQUE_RATIO {speed_ratio torque_ratio} Torque Ratio Torque Ratio Curves Speed Ratio (Sr) $--- CAPACITY_FACTOR {speed_ratio capacity_factor} K-factor@Mp Torque Converter K Curves 176K Speed Ratio (Sr) 11

12 Planetary Gear Set Kinematic coupling between Sun, Carrier, and Ring parts. Uses Adams COUPLER statement, based upon tooth number for each element. Planetary set backlash is modeled through use of a dummy sun and dummy ring part. 12

13 Planetary Gear Set Planetary gear set: (3-way Coupler) λ 0 1 q1 + λ 2 q 2 + λ 3 q3 = P C R Where λ 1, λ 2, λ 3 are related to the tooth numbers of sun (S) and ring (R) gears S λ 1 = 2 ) 3 S, λ = ( S + R and λ = R Gear Lash: (Rotational SFORCE) T l = K T C T e θ 0 θ 0 FUNCTION = BISTOP (AZ (I, J), WZ (I, J, R), θ 1, θ 2, K T, e, C T, d) 13

14 Ravigneax Gear Set Kinematic coupling between Sun, Carrier, and Ring parts. Similar to Planetary Gearset element. Short Pinion Sun Gear 2 Sun Gear 1 Long Pinion Common Ring Gear 14

15 Typical A/Driveline Automatic Transmission Model 15

16 Typical A/Driveline AWD Driveline Model 16

17 Assembled Transmission and Driveline Model 17

18 Exporting to Adams/Chassis 18

19 Integration in Adams/Chassis 19

20 Sample Analysis for Shift Quality 20

21 Conclusions Transmission-specific elements in Adams/Driveline make auto trans model creation easier. Seamless integration with driveline subsystems. Export to Adams/Chassis speeds up creation of vehicle/transmission model. Bottom line: Same great results as with our previous Adams/View-based method, but in less time. Internal customers get results more quickly! 21

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