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

Objectives

• To improve vehicle fuel economy

• To reduce hazardous emissions.

Background on Hybrid Electric Vehicles (HEVs)

• DOE Initiatives PNGV program GATE program

• Series Hybrid Early times

• Parallel Hybrid New trend

Transmission Gearbox

Electric Motor/ Generator

Controller

Operator commands

Feed-back signals

Differential

10

20

30

40

50

60

61 62

Batteries

Engine

WheelWheel

• Toyota Prius (1998)

Notable Hybrid Configurations

Toyota Hybrid System (THS)

3

2

5

1

To Differential

Engine

4

Electric m otorGenerator

Battery pack

Inverter

• 2-DOF (CVT) torque split device

• Continuous mechanical and electrical paths from engine to output shaft

• Uses 2 motor/generators

• Single PG set

Notable Hybrid Configurations

• Honda Insight (2000)

• Integrated Motor Assist Starter Motor Generator Damper

• MYBRID

• 5-speed gearbox

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

• 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

Mechanism Description

No. Operation Mode Clutches Engaged Motor OperatingCondition

Mobility

C1 C2 B1 B2

1 Motor X Motor 1- DOF2 Power1 (P1) X X Motor 1- DOF3 Power2 (P2) X Motor 2- DOF4 Power3 (P3) X X Motor 1- DOF

5 CVT X Generator 2- DOF

6 Engine1 (E1) X X Free Wheeling 1- DOF7 Engine2 (E2) X X Stationary 1- DOF8 Engine3 (E3) X X Free Wheeling 1- DOF9 Engine4 (E4) X X Stationary 1- DOF

10 Regenerative1 (R1) X X Generator 1- DOF11 Regenerative2 (R2) X Generator 2- DOF12 Regenerative3 (R3) X X Generator 1- DOF13 Regenerative4 (R4) X Generator 1- DOF

Operational Modes

• Used to initially move the vehicle from a standstill and for low speed driving in city traffic

• “1st gear” equivalent

Motor Mode (1 DOF)

• Used during low speed, low torque cruising conditions

• Lowest reduction

• “2nd gear” equivalent

Engine 1 Mode (1 DOF)

• For low speed, high torque conditions

• Power-assist compliment to E1

Power 1 Mode (1-DOF)

• Used during moderate speed, average torque conditions

• 1:1 gear ratio (very efficient)

• “3rd gear” or “direct drive” equivalent

Engine 3 Mode (1-DOF)

• For moderate speed, high torque conditions• 1:1 gear ratio (very efficient)• Power-assist compliment to E3

Power 3 Mode (1-DOF)

• Used during highway cruising conditions

• “4th gear” or “overdrive” equivalent

Engine 4 Mode (1-DOF)

• 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)

• Broad speed range, low to moderate torque conditions• CVT operation

Power 2 Mode (2-DOF)

Kinematic and Static Analysis

1 + N414 – (1+N41)3 = 0. (1)

1 + N313 – (1+N41)2 = 0. (2)

N411 + (N41/(1+N31))2-4 = 0. (3)

(1 + N41)1 + (1 + N41/(1 + N31))2 + 3 = 0. (4)

Mode Shifting Analysis

Notional Shifting Strategy

E3

E1

E4

Motor

P2P3

P1

CVTVehicle

Speed

Stopped

Overdrive

2-DOFCharge

2-DOFPower

1-DOFPower & Charge

1st

2nd

3rd

4th

ADVISOR Model

wheel andaxle <wh>

vehicle <veh>

gal

total fuel used (gal)

powerbus <pb>

motor/controller <mc> par

lwt400 <gb>

fuelconverter

<fc> prius

final drive <fd>

exhaust sys<ex>

energystorage <ess>

drive cycle<cyc>

fc_emis

ex_calct

Version &Copyright

AND

emis

HC, CO,NOx, PM (g/s)

fc_trqspd_a

Goto <vc>2

mc_trqspd_a

Goto <vc>1

fc_spd

Goto <svc>

Clock

<vc> greg<sdo> greg

Engine Efficiency Map

Motor Efficiency Map

Operating Limits – Hybrid Modes

ADVISOR Model Results

• UDDS

1

2

3

4

5

0 200 400 600 800 1000 1200 1400

time(sec)

Ge

ar

Se

lec

tio

n

Prius 52.0 mpg (city)Advisor Torque Assist 47.6 mpg (city)LWT400 50.6/59 mpg (city)

0.50

0.55

0.60

0.65

0.70

0 200 400 600 800 1000 1200 1400

time (sec)

% S

OC

Preliminary Data

ADVISOR Model Results

-150

-100

-50

0

50

100

150

200

0 200 400 600 800 1000 1200 1400

time (sec)

Mo

tor

To

rqu

e (

N-m

)

• UDDS

-50

0

50

100

150

0 200 400 600 800 1000 1200 1400

time(sec)

En

gin

e T

orq

ue

(N

-m)

Preliminary Data

Prototype Development

• Based on GM THM-400

• Prototype complete

• Preliminary testing started

• 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

• Testing prototype on the dynamometer

• Continue control and shift strategy evolution

• Integrate in a test vehicle

• Patent pending

• Seeking for support/collaboration

Future Work