1. Development of a Novel Parallel Hybrid Transmission Lung-Wen Tsai Department of Mechanical Engineering University of California Riverside, CA 92521 (909) 787-2128 Lwtsai@engr.ucr.edu

2. Objectives To improve vehicle fuel economy To reduce hazardous emissions.

3. Background on Hybrid Electric Vehicles (HEVs) DOE Initiatives  PNGV program  GATE program Series Hybrid  Early times Parallel Hybrid  New trend

4. Toyota Prius (1998) Notable Hybrid Configurations

5. Toyota Hybrid System (THS) 2-DOF (CVT) torque split device Continuous mechanical and electrical paths from engine to output shaft Uses 2 motor/generators Single PG set

6. Notable Hybrid Configurations Honda Insight (2000) Integrated Motor Assist  Starter  Motor  Generator  Damper MYBRID 5-speed gearbox

7. Notable Hybrid Configurations Chrysler  Dodge Durango (2003)  Electric front wheel drive & conventional rear wheel drive  Dodge Ram Contractor Special (2004)  Hybrid power train & auxiliary power generator Ford Motor Co.  Escape SUV (2003) General Motors  Epsilon platform SUV (2004)  MIBRID ParadiGM system

8. Automatic transmission design with no torque converter Operates as a 1-DOF or 2- DOF (CVT) mechanism  Sums torque  Splits torque Uses only one electric motor/generator 5 basic operational modes LWT Parallel Hybrid Transmission

9. Mechanism Description

10. Operational Modes

11. Used to initially move the vehicle from a standstill and for low speed driving in city traffic “1st gear” equivalent Motor Mode (1 DOF)

12. Used during low speed, low torque cruising conditions Lowest reduction “2nd gear” equivalent Engine 1 Mode (1 DOF)

13. For low speed, high torque conditions Power-assist compliment to E1 Power 1 Mode (1-DOF)

14. Used during moderate speed, average torque conditions 1:1 gear ratio (very efficient) “3rd gear” or “direct drive” equivalent Engine 3 Mode (1-DOF)

15. For moderate speed, high torque conditions 1:1 gear ratio (very efficient) Power-assist compliment to E3 Power 3 Mode (1-DOF)

16. Used during highway cruising conditions “4th gear” or “overdrive” equivalent Engine 4 Mode (1-DOF)

17. Used to charge the batteries when battery state-of-charge is low and power requirement for cruising is low Broad speed range CVT/Charge Mode (2-DOF)

18. Broad speed range, low to moderate torque conditions CVT operation Power 2 Mode (2-DOF)

19. Kinematic and Static Analysis  1 + N 41  4 – (1+N 41 )  3 = 0.(1)  1 + N 31  3 – (1+N 41 )  2 = 0.(2) N 41  1 + (N 41 /(1+N 31 ))  2 -  4 = 0.(3) (1 + N 41 )  1 + (1 + N 41 /(1 + N 31 ))  2 +  3 = 0.(4)

20. Mode Shifting Analysis

21. Notional Shifting Strategy E3 E1 E4 Motor P2P2 P3 P1 CVTCVT Vehicle Speed Stopped Overdrive 2-DOF Charge 2-DOF Power 1-DOF Power & Charge 1st 2nd 3rd 4th

22. ADVISOR Model

23. Engine Efficiency Map

24. Motor Efficiency Map

25. Operating Limits – Hybrid Modes

26. ADVISOR Model Results UDDS Prius52.0 mpg (city) Advisor Torque Assist 47.6 mpg (city) LWT40050.6/59 mpg (city) Preliminary Data

27. ADVISOR Model Results UDDS Preliminary Data

28. Prototype Development Based on GM THM-400 Prototype complete Preliminary testing started

29. A parallel hybrid transmission conceived with:  1-DOF, 2 DOF (CVT), or combination capability  No torque converter  Only one motor/generator  Based on conventional automatic transmission components Torque coupling and gear change transmission in a single embodiment Well suited for hybrids requiring larger motor than MYBRIDS Well suited for front-wheel drive applications Can operate in engine-only modes during low lower cruising Easily manufactured from existing automatic transmission tooling Summary

30. Testing prototype on the dynamometer Continue control and shift strategy evolution Integrate in a test vehicle Patent pending Seeking for support/collaboration Future Work