8/2/2019 Conference 2007
1/27
ARC
Simulink Based Vehicle Cooling
System Simulation;
Series Hybrid Vehicle CoolingSystem Simulation
13th ARC Annual ConferenceMay 16, 2007
SungJin Park, Dohoy Jung, and Dennis N. Assanis
University of Michigan
8/2/2019 Conference 2007
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ARC
Outline
Introduction Motivation
Objectives
Simulation and Integration
Hybrid vehicle system modeling [VESIM]
Cooling system modeling
Configuration of HEV cooling system
Summary
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Vehicle thermal management andcooling system design
Motivation Additional heat sources
(generator, motor, power bus,battery)
Various requirements for differentcomponents
Objective Develop the HEV Cooling System
Simulation for the studies on thedesign and configuration ofcooling system
Optimize the design and theconfiguration of the HEV coolingsystem Conventional Cooling System
Radiator1
OilCooler
FAN
Thermostat
Pump
By-Pass
CAC2
Grille
A/C Condenser
HEV Cooling System
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Overview of Cooling System Simulation
Cooling system model use simulation data from thehybrid system model
Minimizes computational cost for optimization of designand configuration
Hybrid Propulsion System Model [VESIM] HEV Cooling System Model
0
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0 200 400 600 800 1000 1200
1400
Velocity(MPH)
Time (s)
Driving schedule
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time(sec)
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time(sec)
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time(sec)
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Hybrid propulsion systemconfiguration and VESIM
Engine
Generator
Vehicle
Motor
BatteryController
PowerBus
EngineGenerator
Power Bus
Battery
Motor
Wheel
Engine 400 HP(298 kW)
Motor2 x 200 HP(149 kW)
Generator
400 HP
(298 kW)
Battery
(lead-acid)
18Ah /
25 modules
Vehicle
20,000 kg
(44,090 lbs)
Maximumspeed
45 mph
(72 kmph)
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Hybrid vehicle power management
Discharging mode Charging mode Braking mode
Wheel
Motor
Generator
Motor
Power BusControllerEngine
Battery
Wheel
Wheel
Motor
Generator
Motor
Power BusController
Engine
Battery
Wheel
Battery is the primary powersource
When power demand exceedsbattery capacity, the engine isactivated to supplement powerdemand
Power Flow
Active ConditionallyActive
Inactive
Engine / generator is the primarypower source
When battery SOC is lower thanlimit, engine supplies additionalpower to charge the battery
Once the power demand is
determined, engine is operated atmost efficient point
Wheel
Motor
Generator
Motor
Power BusControllerEngine
Battery
Wheel
Regenerative braking is activatedto absorb braking power
When the braking power is largerthan motor or battery limits,friction braking is used
SOC High Limit
SOC Low Limit
Charge Discharge Charge
SOC
Engine Speed
EngineTorque
Efficiency ( engine + generator )
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0.55
0.6
0.65
0.7
0.75
0 100 200 300 400 500
time(sec)-1500
-1000
-500
0
500
1000
1500
-200
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200
400
600
800
1000
1200
1400
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time(sec)
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-100
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200
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1000
1500
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3000
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time(sec)
-1000
-500
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1000
1500
2000
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1000
1500
2000
2500
3000
0 100 200 300 400 500
time(sec)
Vehicle simulationVehicle driving cycle
Cycle simulation results ( engine / generator / motor / battery)
Vehicle simulation model [VESIM]
Engine Speed Generator Speed Motor Speed
Engine BMEP Generator Torque Motor Torque
0
10
20
30
40
50
60
0 100 200 300 400 500
vehicle speed (demand)vehicle speed (actual)
time(sec)
Battery SOC
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Cooling system modeling;Configurations
Configuration A
Motor(A/B)
Generator
PowerBusRadiator1
Engine
Radiator2
FAN
Thermostat
Pump
ElectricPump
By-
Pass
CAC1
Grille
Radiator1
OilCooler
FAN
Thermostat
Pump
By-Pass
CAC2
Grille
A/C Condenser
HEV Cooling System Model in Matlab Simulink
Cooling Circuit for Electric Parts
Cooling Circuit for Engine
Cooling Circuit Tower 2
cac spec
in le ra irve locity
inlet airtemperature
turbo charger
Ramass
thermodelP
coolant temp, K
inlet airvelocity, m/s
inlet airtemp, oC
Ramass1
Tcoolout
thermodelP1
RadelP, bar
to fan
outlet airtemp, K
radiator2
Ramass
thermodelP
coolant temp, K
inlet airvelocity, m/s
inlet airtemp, oC
Ramass1
Tcoolout
thermodelP1
RadelP, bar
to fan
outlet airtemp, K
radiator1
coolant m(kg/s)
coolant density,kg/m3
f low coef f cac
f low coef f egn
coolant flow1
coolant flow2
coolant flow3
m_sum
dp(bar)
parallel coolant circuit2
coolant m(kg/s)
coolant density,kg/m3
coolant flow1
coolant flow2
coolant flow3
m_sum
dp
parallel coolant circuit1
coolant flowrate (kg/s)
coolant temp in (K)
coolant temp
mc temp
motor(A,B)/
controller
coolant flowrate (kg/s)
coolant temp in (K)
coolant temp
gc temp
generator/
control l er
0.2102
0.05466
0.1089
0.3737
0.003829
336.5
flowrate 1
flowrate 2
flowrate 3
fl owsum
dp
temp1
heat rejection, kW
cool mass1
coolant temp
Tcool_out
f low coef f a /b /c
engine block
heat rejection rate
pump speed
engine
pump speed
pressure rise, bar
coolant temp
coolant mass
pressure rise
cool mass, kg/s
coolant temp, K
coolant density, kg/m1
coolant pump2
pump speed
pressure rise, bar
coolant temp
coolant mass
pressure rise
cool mass, kg/s
coolant temp, K
coolant density, kg/m3
coolant pump1
T_pb
T_gen
T_mot
motor_rpm
fan on/off
coolant pump motor /control l er
coolant temp1
coolant mass
delP
recirculate massradiatormass
coolant temp2Re delP
thermo delPdelP1
Remass
Recooltemp
RedelP
Ramass
Racooltemp
RadelP
enginedelP
thermodelP
coolant mass
coolant temp
pressure drop2
collector4
Remass
Recooltemp
RedelP
Ramass
Racooltemp
RadelP
enginedelP
thermodelP
coolant mass
coolant temp
pressure drop2
collector3
T1
T2
m1
m2
Tsum
collector1
T1
T2
T3
m1
m2
m3
Tsum
collector0
fan speed, rpm
vehicle speed, km/h
inlet airtemp, oC
radiator2 spec
radiator1 spec
radi out airT
inlet airvel 1, m/s
inlet airvel 2, m/s
inlet airtemp, oC
ai rs ide, fan
Teng
Telec
fan_rpm
V_speed
Ta
ai rs ide input
rad_air_temp
To Fi l e6
delp.mat
To Fi l e5
mass.mat
To Fi l e4
temp.mat
To Fi l e3
delp_e.mat
To File2
mass_e.mat
To Fi l e1
temp_e.mat
To Fi l e
Terminator2
Terminator
coolant temp1
coolant mass
delP
recirculate mass
radiatormass
coolant temp2
Re delP
thermo delP
T/S temp
delP1
T/S2
Load input data
C_m (kg/s)
C_Tin(K)
C_m(kg/s)
C_Tout(K)
Reservoir2
C_m (kg/s)
C_Tin(K)
C_m(kg/s)
C_Tout(K)
Reservoir1
coolant flowrate (kg/s)
coolant temp in (K)
coolant temp
pb temp
PowerBus
u(1)-273
K->oC
1800
Display3
371 .1
Display1
Clock
f(u)
C2K
cool_mass
coolant temp, K
inlet airvelocity, m/s
inlet airtemp, oC
coolant density, kg/m3
Tcoolout
f low coef f a /b /c
outlet airtemp, K
cac spec
1st charge ai rcooler
MotorGenerator PowerBus
Radiator1
Radiator2
T/S
ElectricPump
Engine
CAC1
ParallelCircuit
ParallelCircuit
Mech.Pump
EngineBlock
Fan
TurboCharger
Cooling Circuit Tower 1
*Run Tower2 firstcopy "to_cac2_t_T.mat"
cac spec
inlerairv elocity
inlet airtemperature
turbo charger
Ramass
thermodelP
coolant temp, K
inlet airvelocity, m/s
inlet airtemp, oC
coolant density, kg/m3
Ramass1
Tcoolout
thermodelP1
RadelP, bar
to fan
outlet airtemp, K
radiator
f(u)
oC->K
pump speed
heat rejection rate
engine
pump speed,
pressure rise, bar
coolant temp
coolant mass
pressure rise (bar)
cool mass, kg/s
coolant temp, K
coolant density, kg/m1
coolant pump
Remass
Recooltemp
RedelP
Ramass
Racooltemp
RadelP
enginedelP
thermodelP
coolant mass
coolant temp
pressure drop2
collector1
fan speed, rpm
vehicle speed, km/h
inlet airtemp, oC
radiator2 spec
radiator1 spec
radi out airT
inlet airvel 1, m/s
inlet airvel 2, m/s
inlet airtemp, oC
airside, fan
Tcool out
fan_rpm
V_speed
Ta
airside input
rad_air_temp
To File
coolant temp1
coolant mass
delP1
delP2
recirculate mass
radiatormass
coolant temp2
Re delP
thermo delP
T/Stemp
delP_sum
T/S
Load input data
C_m (kg/s)
C_Tin(K)
C_m(kg/s)
C_Tout(K)
Reservoir1
coolant flowrate (kg/s)
coolant temp in (K)
heat rejection rate(kW)
coolant temp
cool mass
Oil coolerdp(bar)
Oil cooler1
f(u)
K->oC
0
Display4
0
Display3
0
Display20
Display11
0
Display1
Clock
inlet airvelocity, m/s
inlet airtemp, oC
to fan
outlet airtemp, K
A/C
cool_mass
coolant temp, K
inlet airvelocity, m/s
inlet airtemp, oC
coolant density kg/m3
cool_mass1
Tcoolout1
outlet airtemp, oC
cac spec
delP(bar)
2nd charge aircooler
Radiator
A/CCondenserT/S
CAC2
Mech.Pump
Fan
OilCooler
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Guide Lines ofCooling system configuration
Criteria for system configuration Radiators for different heat
source components areallocated in two towers basedon operation group
The radiators are arranged inthe order of maximumoperating temperature
Electric pumps are used forelectric heat sources
The A/C condenser is placed inthe cooling tower where theheat load is relatively small
Battery is assumed to be cooledby the compartment A/Csystem due to its low operatingtemperature (Lead-acid: 45oC)
ComponentHeat
generation(kW) *
ControlTargetT (oC)
Operationgroup**
Engine 190 120 A
Motor /controller
27 95 B
Generator /
controller
65 95 A
Charge aircooler
13 - A
Oil cooler 40 125 A
Power bus(DC/DC
converter)
5.9 70 C
Battery*** 12 45 D
* Grade Load condition
** The heat sources that generate heat simultaneously duringdriving cycle are grouped together.
*** Maximum speed condition / Lead-acid
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ConfigurationsConfiguration B
Motor(A/B)
PowerBus
Radiator1
Radiator2
FAN
ElectricPump
Grille
ElectricPump
A/C Condenser
Generator
Radiator3
FAN
ElectricPump
Grille
Radiator2
CAC
Radiator1
OilCooler Thermostat
Pump
By-Pass
Engine
Pump
Generator
Radiator3
FAN
ElectricPump3
Grille
Radiator2
CAC
Radiator1OilCooler
Thermostat
Pump1
By-Pass
Engine
Pump2
Motor(A/B)
PowerBus
Radiator1
Radiator2
FAN
ElectricPump
Grille
ElectricPump
A/C Condenser
Configuration C
Po
werGeneration
VehiclePro
pulsion
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Modeling Approach
Component Approach Implementation
Heat Exchanger Thermal resistance concept 2-D FDM Fortran (S-Function)
Pump Performance data-based model Matlab/Simulink
Cooling fan Performance data-based model Fortran (S-Function)
Thermostat Modeled by a pair of valves Fortran (S-Function)
Engine Map-based performance model Matlab/Simulink
Engine block Lumped thermal mass model Matlab/Simulink
Generator Lumped thermal mass model Matlab/Simulink
Power bus Lumped thermal mass model Matlab/Simulink
Motor Lumped thermal mass model Matlab/Simulink
Oil cooler Heat exchanger model (NTU method) Matlab/Simulink
Turbocharger Map-based performance model Matlab/Simulink
Condenser Heat addition model Matlab/Simulink
Charge air cooler Thermal resistance concept 2-D FDM Fortran (S-Function)
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Heat Input and Exchange Model for
Engine Block and ElectricComponents Lumped thermal mass model
Heat transfer to cooling path (Qint) and toouter surface (Qext; radiation and naturalconvection)
Engine Map based engine performance model
Heat rejection rate as a function of speedand load is provided by map
Turbo Charger Map base turbo charger performance
model
The temperature and flow rate of thecharge air as functions of speed and loadare provided by map
Schematic of Heat Exchange Modelat Engine and Electric components
Coolant Flow
Q
Qint
Qext
Modeling Approach:Heat source
Engine heat rejection rate
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Modeling Approach:Heat sources (cont.)
Oil Cooling Circuit
Heat addition model : heat is directly added to the oil Heat rejection rate as a function of speed and load is provided by map
Condenser Heat addition model: heat is directly added to the cooling air
Constant value is used for heat rejection rate
Heat generation from generator is handled as 2-Dlookup table indexed by rotor speed and input torque
Map based Generator and Controller model
1_ TQ genm
Charge air coolers 2-D FDM-based model
In contrast to radiator, heattransfer occurs from air tocoolant
Generator Heat generation is calculated
using a 2D look-up table indexedby speed and input torque
Lumped thermal mass model
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Power Bus Model
mc
mcmc
copbgenpb
wTVIVIabsQ
)1(1_
Battery charging& Motor is working
Otherwise :Motor is working
Motor is generating
mc
mcmc
pbgenpb
wTQ
1_
mcmcmcpbgenpb wTQ 1_
Modeling Approach:Heat sources (cont.)
Motors Heat generation is calculated
using a 2D look-up tableindexed by speed and inputtorque
Lumped thermal mass model
Power bus Power bus regulates the power
from electric power sources andsupply the power to electricpower sink
Heat generation is determined
by battery and motor power Lumped thermal mass model
Heat generation from motor is handled as 2-D lookuptable indexed by rotor speed and output torque
Map based Motor and Controller model
1
1_
TQ genm
Motor
Battery
Power Bus
Motor
Battery
Power Bus
Motor
Battery
Power Bus
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Modeling Approach:Heat sinks
Heat exchanger (radiator)
Design variables Core size
Water tube : depth, height, thickness
Fin : depth, length, pitch, thickness
Louver : length, height, angle, pitch
Based on thermal resistance concept
2-D Finite Difference Method
05.028.068.023.029.014.027.0
49.0
90Re
l
f
l
t
l
l
l
t
l
f
l
f
PP
t
P
P
P
L
P
D
P
L
P
Pj
l
i=12 .
..
Ni
j=1
2
.
.
.
.
.
.
.
Nj
Staggered grid system for FDM
Design parameters of CHE core
Structure of a typical CHE
3/2
,
Prapaa
a
CV
hj
Empirical correlation for ha
(by Chang and Wang)
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Modeling Approach:Heat sinks(cont.)
Oil cooler
Finned concentric pipe heat exchanger modelfor Oil Cooler
Counter flow setup
NTU approach is used to calculate the exittemperature of two fluids
NTU MethodSchematic of Heat Exchange atEngine and Electric components
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Modeling Approach:Delivery media (Coolant)
Coolant Pumps
The coolant flow rate is calculatedwith calculated total pressure drop bycooling system components and thepump operating speed
Performance map is used to calculatethe coolant flow rate
The mechanical pump is driven byengine and electric pump is driven byelectric motor
by- pass
coolant pump
engine
passbyheatpump PPP
radiatorheat PP
by- passby- pass
coolant pump
Heat 1
thermostat
radiator
Coolant circuit(driven by engine)
passbypump PPP
radiatorPP
Heat 2
coolant pump
engine
pumpP radiatorheat PP
coolant pump
Heat 1
radiator
Coolant circuit(driven by motor)
pumpP radiatorPP
Heat 2
Performance Maps of Mechanical Pump
EfficiencyFlow rate
Performance Maps of Electric Pump
EfficiencyFlow rate
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Open
Close
Modeling Approach:Delivery media (Coolant)
radiatorvalveSTrapiperacircuit PPPP _/__
valveSTrepiperecircuit PPP _/__
22
22
reloss
re
re
rere
VK
V
D
Lf
QPV
K
V
D
L
f radiatorra
loss
ra
ra
ra
ra 22
22
P Pipe (radiator circuit)P radiatorP radiatorP
P Pipe (re-circulate circuit)PP T/S_ to_re-circulateP
P T/S_ to_radiatorP
To Pump
From
HeatSources
Valve lift curve of T/S
recircuitracircuit PP __ recircuitracircuit PP __
Coolant flow calculationbased on pressure drop
radiatorcerecirculatctotalc QQQ ___ radiatorcerecirculatctotalc QQQ ___
Thermostats
Two way valve with Hysteresis characteristics Coolant flow rate to re-circulate circuit and radiator are determined
by the pressure drops in each circuit
-2
0
2
4
6
8
10
12
14
365 370 375 380
Temperature (K)
Open
Close
T/S valve lift with hysteresis
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Modeling Approach:Delivery media (Oil/Air)
Oil Pump Map based gear pump model for Oil
Pump
Cooling fans Total pressure drop is calculated from
the air duct system model based on
system resistance concept Performance map is used to calculate
the air flow rate Map Based Gear Pump Model
Cooling air flow circuit
upstream
cooling air flow
Cooling air flow circuit
downstream
radiator2 grilleradiator1fan &shroud
Air duct system based on system resistance concept
condenser
Fan & Shroud
Radiator 1,2
Grille
Condenser
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Test conditions
Test condition for sizing components and evaluating coolingsystem configuration
The thermal management system should be capable ofremoving the waste heat generated by the hardware underextreme operating condition
Grade load condition is found to be most severe condition forcooling system
-0.2
-0.15
-0.1
-0.05
0
0.05
0.1
0.15
0.2
0 200 400 600 800 1000
distance(m)
Road profile of off-road condition
Ambient Temperature 40 oC
45mi/h 30mi/h
30mi/h
7%
Grade Load Maximum Speed Off-Road
C fi i
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Configuration test;Grade Load (30 MPH, 7 %)
Max. SOC: 0.7Min. SOC: 0.6Initial SOC: 0.6
0 200 400 600 800 1000 1200 1400 1600 18000
200
400
600
800
1000
1200
1400
1600
1800
2000
time [sec]
speed[rpm]
Engine speed
0 200 400 600 800 1000 1200 1400 1600 18000
200
400
600
800
1000
1200
1400
1600
Engine BMEP
time [sec]
BMEP[kPa]
0 200 400 600 800 1000 1200 1400 1600 18000.5
0.55
0.6
0.65
0.7
0.75
0.8
time [sec]
SOC
Battery State of Charge
30mi/h
7%
Grade Load
Engine Speed Engine BMEP
Battery SOC
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Configuration A and B
Motor(A/B)
Generator
PowerBusRadiator1
Engine
Radiator2
FAN
Thermostat
Pump
ElectricPump
By-Pass
CAC1
Grille
Motor(A/B)
PowerBus
Radiator1
Radiator2
FAN
ElectricPump
Grille
ElectricPump
A/C Condenser
Generator
Radiator3
FAN
ElectricPump
Grille
Radiator2
CAC
Radiator1
OilCooler
Thermostat
Pump
By-Pass
Engine
Pump
Radiator1
OilCooler
FAN
Thermostat
Pump
By-Pass
CAC2
Grille
A/C C ondenser
Config. A could not meet the cooling
requirements of electric componentsConfiguration A Configuration B
Generator Generator
Motor
PowerBusPowerBus
Motor
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Configuration A and B
Motor(A/B)
Generator
PowerBusRadiator1
Engine
Radiator2
FAN
Thermostat
Pump
ElectricPump
By-Pass
CAC1
Grille
Motor(A/B)
PowerBus
Radiator1
Radiator2
F
ElectricPump
Grille
ElectricPump
A/C Condenser
Generator
Radiator3
FAN
ElectricPump
Grille
Radiator2
CAC
Radiator1
OilCooler
Thermostat
Pump
By-Pass
Engine
Pump
Radiator1
OilCooler
FAN
Thermostat
Pump
By-Pass
CAC2
Grille
A/C C ondenser
Performance of one CAC inConfig. B was better than that oftwo CAC in Config. A
Configuration A Configuration B
CAC1
CAC2
CAC
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Configuration B and C
Motor(A/B)
PowerBus
Radiator1
Radiator2
FAN
ElectricPump
Grille
ElectricPump
A/C C ondenser
Generator
Radiator3
FAN
ElectricPump
Grille
Radiator2
CAC
Radiator1
OilCooler
Thermostat
Pump
By-Pa
ss
Engine
Pump
Config. C is designed by addinga coolant by-pass line to OilCooler in Config. B
Power consumption of pump isreduced by 5% adding thebypass circuit
Generator
Radiator3
FAN
Electric
Pump3
Grille
Radiator2
CAC
Radiator1OilCooler
Thermostat
Pump1
By-Pas
s
Engine
Pump2
Motor(A/B)
PowerBus
Radiator1
Radiator2
FAN
Electric
Pump
Grille
Electric
Pump
A/C Condenser
Configuration B Configuration C
2.5
2.75
3
3.25
3.5
3.75
4
0 300 600 900 1200 1500 1800
no by-passmean (no by-pass)by-passmean (by-pass)
time (sec)
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Summary
The HEV Cooling System Simulation is developed for the
studies of the cooling system design and configuration
The HEV cooling systems are configured using the simulation
In hybrid vehicle, the heat rejection from electric componentsis considerable compared with the heat from the engine ( GradeLoad : heat from electric components 98kW, heat from engine module 240kW)
Proper configuration of cooling system is important for hybridvehicle components, because the electric components workindependently and have different target operatingtemperatures
Parasitic power consumption by the cooling components can be
reduced by optimal configuration design Optimization study of cooling system is conducted using
developed model (Symposium II, Optimal design of electric-hybrid powertrain cooling system)
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Acknowledgement
General Dynamics, Land Systems (GDLS)
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Thank you!