VEHICLE ELECTRIFICATION INCREASES EFFICIENCY AND CONSUMPTION SENSITIVITY · 2016-04-26 · VEHICLE ELECTRIFICATION INCREASES EFFICIENCY AND CONSUMPTION SENSITIVITY. Henning Lohse-Busch,
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VEHICLE ELECTRIFICATION INCREASES EFFICIENCY AND CONSUMPTION SENSITIVITYHenning Lohse-Busch, Ph.D.Argonne National Laboratory
SAE INTERNATIONAL
Argonne’s Center for Transportation Research
2
Materials Research− Tribology
− Thermal Mechanical
Advanced Technology Vehicle Competition (Collegiate)
Modeling and Simulation- CFD Engine Combustion
- Vehicle PT Energy & Controls
Advanced PowertrainResearch Facility
Basic & Applied Combustion Research
- Fuels and After treatment
EV-Smart Grid Interoperability
SAE INTERNATIONAL
Advanced Powertrain Research Facility
3
Vehicle level•Energy consumption
(fuel + electricity)•Emissions•Performance•Vehicle operation and strategy
‘In-situ’ component & system testing•Component performance,
efficiency, and operationover drive cycles
•Component mapping
•Test summary results
•10Hz data of major signals
•Analysis Presentations2WD chassis dynamometer
•Up to medium duty
opened 2002, upgraded 2011
opened 2009
Supportcodes and standards development with
expertise and independent data
Assess state-of-the-art transportation technology
for the Department of Energy and Argonne
research interests
Technology Assessment Codes and Standards
Downloadable Dynamometer Database www.transportation.anl.gov/D3/
Research Oriented Test Facilities Vehicle Technology Assessment
4WD chassis dynamometer•Thermal
Chamber: 0F to 95F
• Solar emulation
You can download all the data in this presentation and recreate the
analysis!
The APRF team enabled this presentation
SAE INTERNATIONAL
OverviewAmerican Retrospective on Automotive EfficiencyPowertrain background• Relentless Progress of Conventional Vehicle• Powertrain Electrification Observations• Electrification Complicates Efficiency CalculationsElectrification Enables Higher Vehicle EfficiencyFactors Impacting Energy Consumption• Impact of Climate Control on Electric Vehicles• Impact of Ambient Temperatures on Hybrid Electric Vehicles• Cold Start Losses on Different PowertrainsSummary Illustration
4
SAE INTERNATIONAL
OverviewAmerican Retrospective on Automotive EfficiencyPowertrain background• Relentless Progress of Conventional Vehicle• Powertrain Electrification Observations• Electrification Complicates Efficiency CalculationsElectrification Enables Higher Vehicle EfficiencyFactors Impacting Energy Consumption• Impact of Climate Control on Electric Vehicles• Impact of Ambient Temperatures on Hybrid Electric Vehicles• Cold Start Losses on Different PowertrainsSummary Illustration
5
SAE INTERNATIONAL
Vehicle Efficiency History in the United States
6
Observations:• From 1985 to 2005 fuel
economy improved minimally while the engine power almost doubled. People buying trucks over cars increases CO2 average.
• In 2005 significant fuel economy improvements occurred corresponding to fuel price volatility at the pump and increased CAFE (Corporate Average Fuel Economy)
EPA report updated annually: www.epa.gov/oms/fetrends.htm
690
640
590
540
490
440
390
340
Adju
sted
CO
2 Em
issi
ons
(g/m
i)
431
400
369
337
306
275
244
212
Adju
sted
CO
2 Em
issi
ons
(g/k
m)
Light-Duty Automotive Technology, Carbon Dioxide Emissions, and Fuel
Economy Trends: 1975 Through 2014
SAE INTERNATIONAL
EPA implemented the new 5 Cycle Fuel Economy Label to close the gap to real world fuel economy the consumer can expect.
EPA’s 5 Cycles Tests for Fuel Economy Label
7
HWFET @ 75 F
0 200 400 600 800 1000 1200 1400 16000
10
20
30
40
50
60
70
80
Time [s]
Spee
d [m
ph]
PhaseTrace
UDDS @ 20 F
0 200 400 600 800 1000 1200 14000
10
20
30
40
50
60
70
80
Time [s]
Spee
d [m
ph]
Phase x10Trace
US06 @ 75 F
0 100 200 300 400 500 6000
10
20
30
40
50
60
70
80
90
Time [s]
Spee
d [m
ph]
Phase x10Trace
0 100 200 300 400 500 6000
10
20
30
40
50
60
Time [s]
Spee
d [m
ph]
Phase x10Trace
SC03 @ 95 FFTP UDDS @ 75 F
0 200 400 600 800 1000 1200 14000
10
20
30
40
50
60
70
80
Time [s]
Spee
d [m
ph]
Phase x10Trace#1 Cold start
#2 Hot start
Classic cycles! Aggressive cycle! Extreme Temperatures!
Parts of these cycles compute into a
City and a Highway Fuel Economy
CAFE (only city and highway)
+850 W/m2
SAE INTERNATIONAL
OverviewAmerican Retrospective on Automotive EfficiencyPowertrain background• Relentless Progress of Conventional Vehicle• Powertrain Electrification Observations• Electrification Complicates Efficiency CalculationsElectrification Enables Higher Vehicle EfficiencyFactors Impacting Energy Consumption• Impact of Climate Control on Electric Vehicles• Impact of Ambient Temperatures on Hybrid Electric Vehicles• Cold Start Losses on Different PowertrainsSummary Illustration
8
SAE INTERNATIONAL
General technology improvement trends:• Improved aerodynamics and lighter weight• Advanced transmissions (high gear number, DCT,
aggressive locking, CVT…)• Advanced engines (VVT, GDI, turbo down sized,
cylinder deactivation, …) • Vehicle system level (start-stop, deceleration fuel cut
off, accessory load electrification)
Relentless Progress of Conventional Vehicles2004 Focus 2012 Focus
Acce
lera
tion
Bra
king
Acce
lera
tion
Bra
king
Vehicle Speed Vehicle Speed
Engine speed [rpm]
Fuel cut off during deceleration
Optimized engine loading
1000
rpm
1500
rpm
2000
rpm
Idle
2L GDI6 spd DCT
2L PFI4 spd auto
Lowered engine speed for 2012
Freq
uenc
y
Engine not fueled
9
SAE INTERNATIONAL
Engine Size, Transmission and Hybrid Efficiency
10
4 cyl. 6 cyl.HEV
6 sp
eed
CVT
6 sp
eed
6 sp
eed
8 sp
eed
Conventional
2013
Niss
an A
ltim
a
2013
Hyu
ndai
Son
ata
2011
For
d Fu
sion
2012
For
d Fu
sion
2012
Chr
ysle
r 300
2010
For
d Fu
sion-
Hybr
id
2011
Hyu
ndai
Son
ata-
Hybr
id
(UDDS cycle) (HWFET cycle)City driving Highway driving
4 cyl. 6 cyl.HEV
6 sp
eed
CVT
6 sp
eed
6 sp
eed
8 sp
eed
Conventional
2013
Niss
an A
ltim
a
2013
Hyu
ndai
Son
ata
2011
For
d Fu
sion
2012
For
d Fu
sion
2012
Chr
ysle
r 300
2010
For
d Fu
sion-
Hybr
id
2011
Hyu
ndai
Son
ata-
Hybr
id
Vehicle efficiency depends on the driving style.
City driving: transient and lower loads with idle periods impact efficiency
Highway driving: higher steady engine loads for higher average efficiency
Technology observationEngine size: smaller engine
higher average efficiencyCVT & 8 speed: enables
optimized engine loading in city driving
HEV: increased freedom to leverage engine operation and enables regenerative braking
SAE INTERNATIONAL
Conventional and Hybrid Vehicle in City Driving
2013 Sonata Conventional: 8.2 l/100km Hybrid system enables:• Engine Start-Stop • EV Operation• Engine Load
Optimization• Regenerative
braking• Accessory HV
electrification (AC, PS,…)
2011 Sonata HEV: 4.9 l/100km
11 Sonata HEV
13 Sonata 2.4L
11
SAE INTERNATIONAL
Engine Load Optimization with Hybrid Systems
12
Fuel
ene
rgy
usag
e [k
J]
2011 Sonata HEV2013 Sonata 2.4L
Engine speed [rpm]1000 1500 2000500
Engine speed [rpm]1000 1500 2000500
150
100
50
0
Fuel
Pow
er [k
W]
Idle fuel
Clustered high load
area
Engine is “ON” 32%
of time
Engine is always “ON”
Spread engine
operation
Data note: UDDS hot start @ 72F Ambient
SAE INTERNATIONAL
How Much Energy Can Be Recovered?B
raki
ng E
nerg
y [W
h]
(UDDS cycle) (HWFET cycle)City driving Highway driving
(US06 cycle)Aggressive driving
2010
Priu
s
2010
Son
ata
HEV
2011
Vol
t
2010
Priu
s
2010
Son
ata
HEV
2011
Vol
t
2010
Priu
s
2010
Son
ata
HEV
2011
Vol
t
The ability to recapture braking energy is fairly complicated and includes:
• Drive cycle• Regen ramp in• Max force and
vehicle dynamics• Limitation may
be other then system limitation
Other: Battery state of charge, Mode/gear shifting, powertrain warm-up, drivability and safety issues (cornering, low friction roads, pot holes…)
13
SAE INTERNATIONAL
Electrification Complicates Efficiency Calculations
14
2012 Focus 2L 2013 Focus BEVBattery
Motor
Fuel
Engine Bi-directional power flow
Irreversible power flow
0 200 400 600 800 1000 1200 14000
500
1000
1500
2000
Time [s]En
ergy
[Wh]
0 200 400 600 800 1000 1200 14000
500
1000
1500
2000
Time [s]
Ener
gy [W
h]
in
out
EnergyEnergyEfficiency =
Regenerative braking reverses the power flow and charges the high voltage battery (In & Out reverse)
Conventional Vehicle Electric Vehicle
SAE J2951 defines “Cycle Energy” as the integration of positive powerat the wheel over the cycle (regenerative braking = “free” energy)
SAE INTERNATIONAL
OverviewAmerican Retrospective on Automotive EfficiencyPowertrain background• Relentless Progress of Conventional Vehicle• Powertrain Electrification Observations• Electrification Complicates Efficiency CalculationsElectrification Enables Higher Vehicle EfficiencyFactors Impacting Energy Consumption• Impact of Climate Control on Electric Vehicles• Impact of Ambient Temperatures on Hybrid Electric Vehicles• Cold Start Losses on Different PowertrainsSummary Illustration
15
SAE INTERNATIONAL
Electrification Enables Higher Vehicle Efficiency
16
0
0.2
0.4
0.6
0.8
1
1.2
0.0 0.2 0.4 0.6 0.8 1.0
Vehi
cle
effic
ienc
y [%
]
Degree of Hybridization (M/(M+E))
72F
Conventional2012 Ford Focus2013 Jetta TDI2013 Chevy Cruze Diesel
Hybrid Electric
2013 Chevy Malibu Eco2013 VW Jetta HEV2013 Honda Civic HEV2010 Prius 2013 Ford Cmax HEV2014 Honda Accord HEV
Battery Electric
2012 Nissan Leaf2013 Nissan Leaf BEV2015 BMW i3 BEV2015 Chevy Spark BEV2013 Ford Focus BEVData note:
UDDS hot start
Peak ICE effPeak ICE eff + regen
SAE
J295
1 de
finiti
on
Conventional BatteryElectric(incl. charger)
Hybrid Electric Observations:• Increased electrification
provides efficiency increase in city type driving to a certain limit
• Pure electric Vehicles are not bound by ICE efficiency
SAE INTERNATIONAL
OverviewAmerican Retrospective on Automotive EfficiencyPowertrain background• Relentless Progress of Conventional Vehicle• Powertrain Electrification Observations• Electrification Complicates Efficiency CalculationsElectrification Enables Higher Vehicle EfficiencyFactors Impacting Energy Consumption• Impact of Climate Control on Electric Vehicles• Impact of Ambient Temperatures on Hybrid Electric Vehicles• Cold Start Losses on Different PowertrainsSummary Illustration
17
SAE INTERNATIONAL
Different Factors Influencing Energy Consumption
18
generation
AccLoads
wheelPowertrain
wheel
Efficiency
dtPower
PowerTempEfficiency
dtPowerEnergy ∫∫ +=
)&(
Powertrain types (CVs, HEVs, PHEVs, BEVs) influence the powertrain efficiency.
Impact of the powertrain
( ) VFtVmPower roadloadwheel ×
+
∂∂
×=
Depends on:• vehicle characteristics
(mass, aero, tires,…)• Driver: speed and
acceleration
Impact of vehicle and driving style
Impact of accessory loads
Air conditioning system, electric heater, ECU, lights,…
Observations:• Interdependence between wheel power and efficiency
• If powertrain efficiency is high and wheel energy low, the accessory loads can very become significant on energy consumption
SAE INTERNATIONAL
Higher Efficiency Powertrains Are More Sensitive
19
Conventional BatteryElectric(incl. charger)
Hybrid Electric
Conventional2012 Ford Focus2013 Jetta TDI2013 Chevy Cruze Diesel
Hybrid Electric
2013 Chevy Malibu Eco2013 VW Jetta HEV2013 Honda Civic HEV2010 Prius 2013 Ford Cmax HEV2014 Honda Accord HEV
Battery Electric
2012 Nissan Leaf BEV2013 Nissan Leaf BEV2015 BMW i3 BEV2015 Chevy Spark BEV2013 Ford Focus BEVData note:
UDDS hot start
Peak ICE effPeak ICE eff + regen
Observations:• Everything matters down to
the accessory loads in electric vehicles.
SAE
J295
1 de
finiti
on
SAE INTERNATIONAL
Electric Vehicles are efficient. It takes about 4-5 kW of electricity on average to complete a city drive cycle
Electric powertrains do not have enough waste heat to warm up the cabin in freezing temperatures
An 4-6 kW electric heater is needed to warm up the cabin
This more than doubles the energy consumption and cuts the range in half
Heater and Air Conditioning Impact on Electric Consumption
UDDS#1 (Cold Start)
20F 72F 95Fsun
20F 72F 95F
20
0 200 400 600 800 1000 1200 14000
10
20
30
40
50
60
70
80
Time [s]
Spee
d [m
ph]
Phase x10Trace
UDDS (City Driving)
2012 Focus BEV
SAE INTERNATIONAL
Electric Range Depends on Drive Cycle, Ambient Temperature and Climate Control Settings
21
20F ambient 95F ambient + 850W/m2
72F ambient
Ran
ge [m
i]
SAE INTERNATIONAL
2010 Toyota Prius Fuel Consumption Results for Different Climate Control Modes
22
Additional mechanical
friction energy.
Additional energy to heat up the cabin.
Permanent extra energy due to colder engine
temperature and constant powertrain friction losses.
Constant extra energy required to run the AC system.
Warm ambient temperature helps improve powertrain
efficiency.
10 Prius
0 200 400 600 800 1000 1200 14000
10
20
30
40
50
60
70
80
Time [s]
Spee
d [m
ph]
Phase x10Trace
UDDS (City Driving)
SAE INTERNATIONAL
Engine Operation of 2010 Prius on UDDS a Range of Ambient Temperatures
23
Observations: 20F fuel island at lower
speed load and engine usage very frequent 95F higher power level
for AC and engine usage more frequent
20F with heater 95F (850 W/m2) with AC72F
Hot s
tart
UDD
S
Hot s
tart
UDD
S
Hot s
tart
UDD
S 10 Prius
0 200 400 600 800 1000 1200 14000
10
20
30
40
50
60
70
80
Time [s]
Spee
d [m
ph]
Phase x10Trace
UDDS (City Driving)
Cold
star
t UDD
S
Cold
star
t UDD
S
Cold
star
t UDD
S
Fuel
ene
rgy
usag
e [k
J]
EO = Engine On time in [%]Histogram is frequency
SAE INTERNATIONAL
Cold Start Penalty at Different Temperatures
24
20F: Highest cold start penalty– Penalty is due to high
powertrain losses with high friction for all vehicles
– The losses during a cold start are higher for a powertrain using an engine
72F: – Baseline 95F:
– PEVs show higher cold start penalties at 95F which may be due to cabin temperature pull down and higher baseline powertrain efficiencies
Energy consumption increase between cold start and hot start UDDS
SAE INTERNATIONAL
OverviewAmerican Retrospective on Automotive EfficiencyPowertrain background• Relentless Progress of Conventional Vehicle• Powertrain Electrification Observations• Electrification Complicates Efficiency CalculationsElectrification Enables Higher Vehicle EfficiencyFactors Impacting Energy Consumption• Impact of Climate Control on Electric Vehicles• Impact of Ambient Temperatures on Hybrid Electric Vehicles• Cold Start Losses on Different PowertrainsSummary Illustration
25
SAE INTERNATIONAL
Using the Heater in an Electric Car may Double the Energy Consumption in City Type Driving
Ener
gy c
onsu
mpt
ion
[Wh/
mi]
UDDS(City driving)
Hea
ter
AC
20F 95F72F
HWFET(Highway driving)
US06(Aggressive driving)
2012 Nissan Leaf
Electric Vehicle+91%
+20%
Test Notes: • Cold start vehicle soaked at target
temperature for at least 12hr. Powertrain is hot in the other tests.
• Climate control setting to 72F automatic.
• 95F include 850 W/m2 of radiant energy.
26
SAE INTERNATIONAL
Driving at Higher Speeds and Aggressively will Increase the Energy Consumption in an Electric Car
UDDS(City driving)
72F
HWFET(Highway driving)
US06(Aggressive driving)
72F 72F
2012 Nissan Leaf
Electric Vehicle+19%
+72%
27
Ener
gy c
onsu
mpt
ion
[Wh/
mi]
SAE INTERNATIONAL
Generally Increased Driving Intensity Translate to Higher Consumption Except for the Conventional due to Low Efficiency in the City
28
72F 72F 72F
+19%+72%
+4%
+5%
-32% +60%
UDDS(City driving)
HWFET(Highway driving)
US06(Aggressive driving)
Ener
gy c
onsu
mpt
ion
[Wh/
mi]
2010 Toyota Prius
Full Hybrid
2012 Nissan Leaf
Electric Vehicle
Conventional
2012 Ford Focus
SAE INTERNATIONAL
Cold Start Energy Consumption is Larger than Hot Start Energy Consumption
Ener
gy c
onsu
mpt
ion
[Wh/
mi]
UDDS(City driving)
Hea
ter
AC
20F 95F72F
HWFET(Highway driving)
US06(Aggressive driving)
2012 Nissan Leaf
Electric Vehicle+11%
+7% +12%
29
SAE INTERNATIONAL
Largest Energy Consumption Increase for an EV Occurs at 20F and for a Conventional at 95F
Ener
gy c
onsu
mpt
ion
[Wh/
mi]
UDDS(City driving)
Hea
ter
AC
20F 95F72F
HWFET(Highway driving)
US06(Aggressive driving)
2010 Toyota Prius
Full Hybrid
2012 Nissan Leaf
Electric Vehicle
Conventional
2012 Ford Focus
+91%
+20%
+65% +56%
+7%
+27%
Note:• At 20F, the EV has to use an electric heater to heat the cabin and the conventional can use the engine heat. • At 95F the conventional uses the mechanical compressor belted to the engine which is less efficient than the high voltage compressor in the EV. • The powertrain operation change for hybrids at 20F and 95F compared to 72F.
30
SAE INTERNATIONAL
A Conventional Vehicle has the Largest Absolute Energy Consumption Penalty on a Cold Start
Ener
gy c
onsu
mpt
ion
[Wh/
mi]
UDDS(City driving)
Hea
ter
AC
20F 95F72F
HWFET(Highway driving)
US06(Aggressive driving)
2012 Nissan Leaf
Electric Vehicle
Conventional
2012 Ford Focus
+1%
+6%
+8%
+15%
+7%
+4%
+11%
+7% +12%
2010 Toyota Prius
Full Hybrid
31
SAE INTERNATIONAL
Ener
gy c
onsu
mpt
ion
[Wh/
mi]
UDDS(City driving)
HWFET(Highway driving)
US06(Aggressive driving)
Hea
ter
AC
20F 95F72F
Hea
ter
AC
20F 95F72F
Hea
ter
AC
20F 95F72F
2012 Nissan Leaf
Electric Vehicle
Conventional
2012 Ford Focus
2010 Toyota Prius
Full Hybrid
Driving Usage and Climates Affect Energy Consumption Across Different Powertrains
Test Notes: 1) Cold start vehicle soaked at target temperature for at least 12hr. Powertrain is hot in the other tests. 2) Climate control setting to 72F automatic. 3) 95F includes 850 W/m2 of radiant energy 32
VEHICLE ELECTRIFICATION INCREASES EFFICIENCY AND CONSUMPTION SENSITIVITYHenning Lohse-Busch, Ph.D.Argonne National Laboratory
www.transportation.anl.gov/D3
Work sponsored by Lee Slezak
and David Anderson from
the Vehicle Technologies
Office at the U.S. Department of
Energy
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