Embed Size (px)
Citation preview
Tradeoff Between PowertrainTradeoff Between Powertrain Complexity and Fuel Efficiency
2009 DOE Hydrogen Program and Vehicle Technologies A l M i R iAnnual Merit Review
June 08, 2010
Namdoo Kim (PI), Aymeric Rousseau (Presenter)Argonne National Laboratory
Sponsored by Lee SlezakProject ID #VSS010
This presentation does not contain any proprietary, confidential, or otherwise restricted information
Project ID #VSS010
Project OverviewTimeline
Start – September 2009
Barriers Evaluate fuel consumption potential
End – September 2010
70% Complete
and cost benefit of powertrains
Assess impact on component requirements
Budget FY09 ‐ $150K (2Mode
q
FY09 $150K (2Mode Development and Validation)
FY10 ‐ $400K
2
Objectives
The objective is to evaluate the benefits of several multi‐mode powertrain configurations from a fuel
consumption and cost point of view.
EVT efficiency of electro‐mechanical power path increases with powertrain (PT) configuration complexitypowertrain (PT) configuration complexity
EVT mechanical losses also increase with PT complexity
Evaluate the trade‐offs between EVT system efficiency and EVTEvaluate the trade offs between EVT system efficiency and EVT mechanical loss based on multi‐mode powertrain complexity
Select the most promising configuration to support future DOE
3
fuel consumption studies
EVT Hybrid
An EVT hybrid uses differential gearing to split power into two paths:
ll h l– All‐Mechanical
– Electro‐Mechanical
EVT gearing acts like an automobile differential, which uses gearing to split power between left andright wheels.
Series – Engine Operates Independently
– + Continuously Variable (CVT) Operation, y ( ) p ,
– + Unlimited Transmission Speed Ratio
Parallel – Mechanical Path Through
+ Motors and Controllers Cost Less– + Motors and Controllers Cost Less,
– + Higher Transmission Efficiency.
4
MilestonesYear 1 Year 2
Analyze APRF test data
Implement component dataImplement component data
Develop 2 Mode control
Validate 2 Mode model
Develop 3 Mode transmission
Develop 3 Mode control
Develop 4 Mode transmissionDevelop 4 Mode transmission
Develop 4 Mode control
Size Vehicles
Run Simulations
Provide Report
Current Status
5
ApproachDevelop Transmission
Models of Selected Patents
Search Existing Patents for Multi Mode HEV m
ption ?
Develop Vehicle Level C t l B d A il bl
Fuel Con
sum
Control Based on Available Test Data and Literature Powertrain Configuration
Complexity
6
Technical AccomplishmentsU d t d Effi i P t ti l f E h M lti M dUnderstand Efficiency Potential of Each Multi-Mode
Input Split
1
1.5
The ratio P-elect to P-eng, Single Mode EVTConstant Engine Torque and Engine Speed (@ W-eng=1500rpm, T-eng=120Nm)
0.95
1Efficiency
“All-Mechanical” Power “All-Input” Power
-0 5
0
0.5
Pwr R
atio
0.8
0.85
0.9
Eff.
“Mechanical Point”ratio :0.72
-1.5
-1
-0.5P
EVT10.65
0.7
0.75
EVT1
“Electro-Mechanical” Power Efficiency drops sharply at low SR (high vehicle speed)
0 0.5 1 1.5 2 2.5-2
SR, the ratio of W-eng to W-out 0 0.5 1 1.5 2 2.5
SR, the ratio of W-eng to W-out
Power ratio = electro mechanical power / all mechanical power
7
Power ratio = electro‐mechanical power / all‐mechanical power (small values mean little recirculation, higher efficiencies)
Patented in the US in 1969
Technical AccomplishmentsU d t d Effi i P t ti l f E h M lti M dUnderstand Efficiency Potential of Each Multi-Mode
Dual ModeEffi i (@ W 1500 T 100N )
The ratio P-elect to P-eng , Two Mode EVT (GM P 6,478,705)C t t E i T d E i S d (@ W 1500 T 100N )
0.8
0.9
1Efficiency (@ W-eng=1500rpm, T-eng=100Nm)
1
1.5
2Constant Engine Torque and Engine Speed (@ W-eng=1500rpm, T-eng=100Nm)
“All-Mechanical” Power
“Mechanical Point”
“All-Input” Power
0.6
0.7Eff.
-1
-0.5
0
0.5
Pwr R
atio
“Electro-Mechanical” Power
Mechanical Point
0 0.5 1 1.5 2 2.5 3 3.5 40.4
0.5
SR, the ratio of W-eng to W-out
EVT1EVT2
0 0.5 1 1.5 2 2.5 3 3.5 4-2
-1.5
SR, the ratio of W-eng to W-out
EVT1 (Input Split)EVT2 (Compound Split)
The objective is to minimize the power ratio, to minimize recirculation
Power through the transmission (engine to output) is the sum of all‐mechanical power and electro‐mechanical power.
8
Transmit more power mechanically, which is more efficient. Two mechanical points allow higher efficiency over wider range
GM patent no. 6,478,705
Technical AccomplishmentsU d t d Effi i P t ti l f E h M lti M dUnderstand Efficiency Potential of Each Multi-Mode
Three Mode
0.9
1Efficiency (@ W-eng=1500rpm, T-eng=100Nm)
EVT1EVT2EVT3
1
1.5
2
The ratio P-elect to P-eng , Three Mode EVT (GM P 6,551,208)Constant Engine Torque and Engine Speed (@ W-eng=1500rpm, T-eng=100Nm)
EVT1 (Input Split)EVT2 (Compound Split)EVT3 (Compound Split)
0.6
0.7
0.8
Eff.
-0.5
0
0.5
Pwr R
atio
0 0.5 1 1.5 2 2.5 3 3.5 40.4
0.5
SR, the ratio of W-eng to W-out
0 0.5 1 1.5 2 2.5 3 3.5 4-2
-1.5
-1
SR, the ratio of W-eng to W-out
Power through the transmission (engine to output) is the sum of all‐mechanicalpower and electro‐mechanical power.
9
Transmit more power mechanically, which is more efficient.
Maintain high efficiency over a wider rangeGM patent no. 6,551,208
Technical Accomplishments Multi Mode Efficiency Potential SummaryMulti-Mode Efficiency Potential Summary
Single Two Three Four
Eff. of electro‐mechanical power path 0 + ++ +++p p
Electro‐mechanical capacity 0 + ++ +++
Cost 0 ‐ ‐‐ ‐‐
Oil pump loss 0Oil pump loss 0 ‐ ‐ ‐
Planetary gear spin loss 0 ‐ ‐‐ ‐‐
Clutch drag loss 0 ‐ ‐‐ ‐‐
Transmission model needs to include:
Oil Pump LossPlanetary GearClutch drag losses
Key: Baseline = 0, Better = +, Worse = ‐
0.150
0.200
0.250
0.300
0.350 0 bar
5 bar
10 bar
16 bar
Oil Pump Loss Planetary Gear Spin Losses
Clutch drag losses
10
0.000
0.050
0.100
0 1000 2000 3000 4000 5000 6000 7000 8000
Spin loss : 99.5%
Technical AccomplishmentsM d l d Diff t T i iModeled Different Transmissions
Gear System
‐ Transmission models developed in SimDriveline to allow for modeling of detailed losses (oil pump spin
:
of detailed losses (oil pump, spin, clutch drag).‐ Low level control developed for each transmission
11
::
Technical AccomplishmentsD l d Si l 2 d 3 M d C t lDeveloped Single, 2 and 3 Mode Controls
Control Logic Philosophy
Controller objective: Find the power split between mechanical components (ICE, MC2, MC1) that meets the driver request for the current speed of the vehicle, while maintaining acceptable battery SOC and minimal fuel consumption
Use a compound split mode– Use a compound split mode
– Electric power should stay low with wide ratio coverage
Mode selection rule is defined by maps which are computed in Matlab using a brute‐Mode selection rule is defined by maps which are computed in Matlab using a brute‐force algorithm (similar to instantaneous optimization)
The SOC correction and engine ON/OFF conditions have to be properly defined
outT out
ecandidate
ontransmissi
MCMC
MCMC
TT
2,1
2,1
eTEquations(Two modes & fixed gear modes)
nConsumptioFuelCandidate
12
Note: an instantaneous optimization has also been defined for the 2Mode
ontransmissi
Technical AccomplishmentsI t f P t i C t Si i d O tiImpact of Powertrain on Component Sizing and Operation
Single Dual
Small SUV Vehicle Sizing Veh Spd, m/s x10Eng ONGB Mode x100
UnitSingle Mode
Dual Mode
Engine Power kW 195 191
Motor 1 Power kW 110 49 200
300UDDS - Part 2 - Engine speed and torqueSingle Mode
GB Mode x100Eng Spd, rpm /10Eng Trq, Nm
Motor 1 Power kW 110 49
Motor 2 Power kW 90 60
Vehicle Weight kg 2026 19830
100
200
150 200 250 300 350
400
500UDDS - Part 2 - Engine speed and torqueDual Mode
Dual mode allows smaller electric machines
100
200
300
400electric machines
Mode selection also impact the component operating conditions (e g engine speed
13
150 200 250 300 350
0
Cycle is UDDS Hill 2
conditions (e.g., engine speed and torque)
Technical AccomplishmentsV lid t Si l d D l M d C t lValidate Single and Dual Mode Controls
Analyze Data Develop Control
Collect Test Data
Engine Torque
Validate Model
APRF
Understand Gearbox Model Gearbox
Source : GM
14
Example of GM 2 Mode Tahoe
Future Activities
Multi‐mode analysis completion Refine / develop the design options and control of three and four mode
powertrains
Complete fuel efficiency comparison and analysis study based on a small SUV
To ensure fair comparison, several control parameters will be simulated and/or heuristic optimization algorithm will be used to tune the parameters
Several drive cycles, include RWDC might be considered
Net Present Value (NPV) will also be consideredNet Present Value (NPV) will also be considered
Expand study– Additional vehicle classes (e.g., compact, midsize car, midsize SUV…)
– Additional multi‐mode (e.g., 5, 6…) if the tip not reached
– Other configurations options (e.g., for series, compare series vs. GM Volt vs. BYD…)
15
Summary
The fuel efficiency potential of several multimode systems (1 to 4 modes) has been defined.
Detailed transmission models, including spin losses, clutch drag and oil pump losses have been developed along with their low level controllers.
Vehicle level control strategies have been defined for several multi‐mode systems (1, 2 and 3).
For the small SUV application considered, preliminary results show impact on component sizing and component operating conditions
Future work will address the four selected multi‐mode systems to assess their impact on fuel consumption and component i i
16
sizing.
16
Additional Slides
17
List of Publications
Karbowski, D., Kwon, J., Kim, N., Rousseau, A., “Instantaneously Optimized Controller for a Multimode Hybrid Electric Vehicle”, SAE 2010‐01‐0816, SAE World Congress, Detroit, April 2010g , , p
N. Kim, A. Rousseau, R. Carlson, F. Jehlik, “Tahoe HEV Model Development in PSAT”, SAE 2009‐01‐1307, World Congress, April 2009
B. Carlson, J. Kim, A. Rousseau, “GM Tahoe 2 Mode System”, DOEB. Carlson, J. Kim, A. Rousseau, GM Tahoe 2 Mode System , DOE Presentation, June 2008, Washington DC
1818
Single Mode EVT :
Lever and stick diagrams for a simple planetary EVT (Input split):
EGMC2 MC78 30
S C R
OUT
A lever can be drawn in the same orientation as planetary “sticks”. – Patented in the US in 1969!
Toyota Prius uses this same basic gear schematic and power flow– Toyota Prius uses this same basic gear schematic and power flow
Engine torque is split unequally, based on ring‐to‐sun gear ratio.
Final drive receives most of the engine torque directly.
Generator receives a small fraction of engine torque (e g 1/3) but must be able to
19
Generator receives a small fraction of engine torque (e.g. 1/3) but must be able to turn much faster than the engine.
Single Mode EVT Limitations
Electro‐mechanical (continuously variable) power path is less efficient due to electrical power recirculation.
EVT gear ratio or “mechanical point” must be chosen for high drive‐cycle fuel EVT gear ratio or mechanical point must be chosen for high drive‐cycle fuel economy (no recirculation).
With high engine speed, transmission uses high speed ratios, with high electro‐mechanical power.
High electro‐mechanical component power has high cost.
High electro‐mechanical use increases “real‐world” fuel consumption.
20
EVT Power Split Design Options:
Input Split (IS), Output Split, and Compound Split (CS) EVT hybrids use gearing in different places:– I.S. : One electric motor is geared at the input, and the other motor turns with the output
C S : One electric motor is geared at the input and the other is geared at the output– C.S. : One electric motor is geared at the input, and the other is geared at the output.
21
Input split, output split and compound split can be combined to form a multi‐mode EVT
Two Mode EVT :
Lever and stick diagrams for a two mode EVT; for example
GM patent no. 6,478,705EGMC2 EGMC2
CL1S1 C1 R1
MCOUTCL2 R2 C2 S2
Engine is connected to the 1st ring gear.
Generator is connected to the 1st sun gear.
i d h 2 d Motor is connected to the 2nd sun gear.
Final drive is connected to the planet carrier
Two clutches are provided, one for each EVT range or “mode”. (Mechanical loss)
d l f d ( h l l )
22
Needs two planetary gear sets for EVT2 mode. (Mechanical loss)
Three Mode EVT :
Lever and stick diagrams for a three mode EVT; for example
GM patent no. 6,551,208EGMC2
MC
CL2
CL1S1 C1 R1
R2 C2S2
OUT
CL2
CL4
CL3C2
R3
C3S3
Engine is connected to the 1st ring gear.
Generator is connected to the 1st sun gear.
i d h 2 d Motor is connected to the 2nd sun gear.
Final drive is connected to the 3rd planet carrier
Four clutches are provided, two for each EVT range or “mode”. (Mechanical loss)
d h l f d ( h l l )
23
Needs three planetary gear sets for EVT2, EVT3 mode. (Mechanical loss)
