Energy Efficiency of A Pragmatic View - IEEEewh.ieee.org/conf/vppc/Speaker/KS02-8_Bob_Lee.pdf ·...
Transcript of Energy Efficiency of A Pragmatic View - IEEEewh.ieee.org/conf/vppc/Speaker/KS02-8_Bob_Lee.pdf ·...
Energy Efficiency of Automobiles –A Pragmatic View
Bob Lee
Vice President ‐ Powertrain Product Engineering
Chrysler Group LLC
IEEE Vehicle Power and Propulsion ConferenceDearborn, MichiganSeptember 9, 2009
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IEEE Space
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Outline
• Energy efficiency space
• Fuel economy and energy efficiency
• Where does the energy go
• Fuel economy ideal function
• Pragmatic energy efficiency improvement model
• Summary
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Energy Efficiency Space
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What is “Efficiency” ?
The dictionary defines efficiency as:
• The ratio of the effective or useful output to the total input in any system
• The ratio of the energy delivered by a dynamic system to the energy supplied for its operation
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What is “ Energy Efficiency”
“Take the Stairs‐‐Be More Energy Efficient”
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The Physics: Converting Fuel Energy to Work
FEC (Highway) Drive Trace
Ftire Ftrac
Faero
MgFbrake
Laws of PhysicsForce = Mass x Acceleration
Torque = Inertia x Angular AccelConservation of Energy
1st Law of ThermodynamicsLower Heating Value of FuelWork = Force x Distance
…and so on
Mph
Time
Fuel Economy generally refers to how much distance a specific vehicle can be moved from A to B with a given volume of fuel. Fuel Efficiency generally refers to how well the energy of the fuel is converted into useful work.
Fuel Economy
= 28.6 mpg
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Key Fuel Economy MetricsFuel Economy Labels
Regulatory requirement, but also used competitively (can be advertised)Administered by EPA with Manufacturer self‐certification
Consumer ReportsCompetitive testing by highly influential Independent 3rd partyCannot be advertisedChrysler strategic objective is to be top quartile in each segment
Corporate Average Fuel Economy (CAFE)Fleet mpg average, administered by NHTSA
European Union Fuel Consumption
Expressed as Liters/100 Km on unique New European Driving Cycle (NEDC)Homologation testing conducted by Manufacturer with an EU approved witnessWidely reported (German Auto Motor und Sport is similar to Consumer Reports) and can be advertised
CO2 Emissions (Greenhouse gas “pollutant”) Inversely proportional to mpg fuel economy (directly proportional to fuel consumption) for a given fuel. Expressed as gm/mi or gm/kmVoluntary fleet average agreement exists between Manufacturers Association (ACEA) and the European Union
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Key Metrics & Cycles – Fuel Economy Labels
FTP City Drive Cycle
HWFET Highway Drive Cycle
US06 High Speed Drive Cycle
SC03 Air Conditioning Drive Cycle20°F Cold City Drive Cycle
EPA City and Highway label values are calculated as weighted combinations of 5 key tests. They are posted on the new vehicle’s window label along with a competitive segment position. The city, highway and cold city cycles feature light engine loads and mostly low vehicle speeds.
57 mph
57 mph
81 mph
60 mph
55 mph
The FTP City and HWFET Highway are also combined into an EPA unadjusted value for use in CAFE
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Energy Supply from Internal Combustion EngineOnly about 1/3 of the fuel energy is converted by the internal combustion gasoline engine into vehicle work. Advanced gasoline engine technologies (and diesels as well) are aimed at improving the efficiencies and reducing the losses associated with the other 2/3 of the energy available.
To Work
Losses
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Where the Vehicle Energy is Spent in City Driving
Most of the fuel energy on a city type cycle is consumed by (repeatedly) accelerating the mass (weight) of the vehicle, but other vehicle demands & losses take energy also.
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Where the Vehicle Energy is Spent in Highway Driving
Most of the fuel energy on a highway type cycle is consumed overcoming the aerodynamic drag of the vehicle, but other demands & losses take energy as well.
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Thermal Efficiency (Comp Ratio)Combustion Efficiency
Heat/Mass LossPumping Work
Mechanical Friction
Variable Compression Ratio Direct Injection
Downsizing & Pressure ChargingVariable Valve Lift/Timing
Multi‐Displacement Sys (Cyl Deact)Diesel
Hybrid (Regen Braking, E‐drive)Fuel Cell
Technologies
Energy Demand(Vehicle Loads, Efficiencies, and Losses)
Vehicle SizeMaterial SubstitutionWeight OptimizationLoads / Duty Cycles
Weight Aero Drag Road Loads Accessory Loads Drivetrain Losses
Frontal Area / HeightDrag CoefficientFront End SealingBelly Pans/FairingsGrille Shutters
Rolling ResistanceBrake DragBearing Drag
Electric Pwr SteeringVar Disp CompressorElectrical Load Mgmt
LED tail lightsVar Speed Fuel Pump
Radiator SizingVar Speed Fan
Reflective Coatings
Torque ConverterDual Clutch TransCont Variable Trans
Axle/ LubeFront Axle DisconnectWheel Size (Inertia)
DesignTechnologies
DesignTechnologies
DesignTechnologies
DesignTechnologies
DesignTechnologies
Energy Supply and Vehicle DemandThe Physics: Fuel Economy is a function of the total vehicle system, comprising both energy supply in the propulsion system and energy demand of and from the vehicle. Improving it thus requires a total vehicle solution.
Energy Supply(Conversion Efficiency and Losses)
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0
5
10
15
20
25
30
35
40
10 15 20 25 30 35 40 45 50 55 60 65 70
Vehicle Speed [mph]
Road
Load Po
wer [h
p]
Aerodynamic
Transmission/Driveline
Hubs/Bearings
Brakes
Tires ‐ P225/55/R19 Kumho Solus KH16
Road Load ‐ Subsystem Contributors
Data Source: Chrysler LLC, Dept. 7300
EPA CityAverage Speed
21 mph
EPA HighwayAverage Speed
48 mph
EPA CombinedAverage Speed
33 mph
CR HighwayAverage Speed
65 mph
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Pragmatic Efficiency Improvement Model
•Gains in propulsion efficiency are best built upon reduced vehicle energy demand, as it maximizes the impact of transmission matching and allows engine size and technology to be optimized.
Driver
• Customers• Regulations• Competition• Suppliers• Energy Cost
• Customers• Regulations• Competition• Suppliers• Energy Cost
VehicleEnergyDemand
VehicleEnergyDemand
Transmission / DrivelineMatching
EngineImprovement
Enabler Enabler
Overall Objectives
• Improve fuel economy
• Refinement
• Cost and complexity reduction
• Competitive performance
Electrification(HEV, ReEV, BEV)Electrification(HEV, ReEV, BEV)
Enabler
Priority:Best Bang
for Buck
Priority:Best Bang
for Buck
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Pragmatic Efficiency Improvement Model
•Gains in propulsion efficiency are best built upon reduced vehicle energy demand, as it maximizes the impact of transmission matching and allows engine size and technology to be optimized.
Driver
• Customers• Regulations• Competition• Suppliers• Energy Cost
• Customers• Regulations• Competition• Suppliers• Energy Cost
VehicleEnergyDemand
VehicleEnergyDemand
Transmission / DrivelineMatching
EngineImprovement
Enabler Enabler
Overall Objectives
• Improve fuel economy
• Refinement
• Cost and complexity reduction
• Competitive performance
Electrification(HEV, ReEV, BEV)Electrification(HEV, ReEV, BEV)
Enabler
Priority:Best Bang
for Buck
Priority:Best Bang
for Buck
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ProductsBenefitsTechnology
Transmission and Driveline – Efficient and Light Weight Axle Technology
Fuel Efficient Rear and Front Drive Unitsfor Pass Car
& SUVOpen diff, LSD, eLSD
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Pragmatic Efficiency Improvement Model
•Gains in propulsion efficiency are best built upon reduced vehicle energy demand, as it maximizes the impact of transmission matching and allows engine size and technology to be optimized.
Driver
• Customers• Regulations• Competition• Suppliers• Energy Cost
• Customers• Regulations• Competition• Suppliers• Energy Cost
VehicleEnergyDemand
VehicleEnergyDemand
Transmission / DrivelineMatching
EngineImprovement
Enabler Enabler
Overall Objectives
• Improve fuel economy
• Refinement
• Cost and complexity reduction
• Competitive performance
Electrification(HEV, ReEV, BEV)Electrification(HEV, ReEV, BEV)
Enabler
Priority:Best Bang
for Buck
Priority:Best Bang
for Buck
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Electrified System Optimization
Electrical Losses EMA
-1 00
1 0
-2 0 00
2 0 00
5 0
1 0 0
n EM 1 [ 1 0 0M EM 1 [ N m ]P
VEM
1 [KW
]
05000
0200
4000
10
20
nVM [1/min]MVM [Nm]
PV
B [KW
]
Electrical Losses EMB
-1 00
1 0
-2 0 00
2 0 00
5 0
1 0 0
n EM 1 [ 1 0 0M EM 1 [ N m ]
PV
EM1 [K
W]
Battery Losses
CombustionEngine Losses
02000
400060
0200
4000
200
400
600
nVM [1/min]MVM [Nm]
PV
M [K
W]
+Transmission Pump Losses
02
4
02
40
20
40
nVM [1000/min]nAB [1000/min]
PV
G [K
W]+ =
0
5
0
2 0 0
4 0 00
5 0 0
1 0 0 0
1 5 0 0
N IC E [ 1 0 0 0T ICE [N m ]
PL [K
W]
M[N
m]
Overall Powertrain
System Loss
The optimal solution is found in the minimal point of the sum of all losses
Controls & Simulation
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Pragmatic Model
•Gains in propulsion efficiency are best built upon reduced vehicle energy demand, as it maximizes the impact of transmission matching and allows engine size and technology to be optimized.
Driver
• Customers• Regulations• Competition• Suppliers• Energy Cost
• Customers• Regulations• Competition• Suppliers• Energy Cost
VehicleEnergyDemand
VehicleEnergyDemand
Transmission / DrivelineMatching
EngineImprovement
Enabler Enabler
Overall Objectives
• Improve fuel economy
• Refinement
• Cost and complexity reduction
• Competitive performance
Electrification(HEV, ReEV, BEV)Electrification(HEV, ReEV, BEV)
Enabler
Priority:Best Bang
for Buck
Priority:Best Bang
for Buck
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Summary
• Automobile energy efficiency can be viewed as the relationship between Vehicle Demand Energy and Propulsion Efficiency over a given drive cycle
• Increasing energy efficiency should be a total vehicle exercise requiring detailed improvements in both Vehicle Demand Energy and Propulsion Efficiency
• Reductions in Vehicle Demand Energy typically provide better "Bang for the Buck" and are synergistic with electrification scenarios
• Electrified powertrains require closer cooperation between the traditional mechanical and electrical disciplines to maximize energy efficiency
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Thank You