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外文资料翻译
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的
是
一
篇
国
外
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生
的
毕
业
论
文
中
的
一
段
论
文
名
字
是
“
A
Comprehensive
Thermal
Management
System
Model
for
Hybrid
Electric
Vehicles
”
）
The
automotive
industry
is
facing
unprecedented
challenges
due
to
energy
and
environmental issues.
The emission regulation is becoming strict and the
price of
oil
is
increasing.
Thus,
the
automotive
industry
requires
high-efficiency
powertrains
for
automobiles
to
reduce
fuel
consumption
and
emissions.
Among
high-efficiency powertrain vehicles,
Hy-brid Electric Vehicles (HEVs) are under
development and in production as one
potential solution to these problems. Thus,
one
of
the
most
critical
objectives
of
the
HEV
development
is
improving
fuel
economy.
There
are
many
ways
of
maximizing
the
fuel
econo-my
of
a
vehicle
such
as
brake
power
regeneration
，
effici
ent
engine
operation
< br>，
parasitic
loss
minimization
，
reduction
of
vehicle
aerodynamic
drag,
and
engine
idle
stop.
Figure
1
compares
the
balance
of
the
energy
of
a
conventional
vehicle
with
a
hybrid
electric vehicle
。
As can be
seen in Figure 1, the hybrid vehicle saves fuel
by
utilizing
engine
idle
stop,
brake
power
regeneration,
and
efficient
engine
operation. Figure 1 also shows that the
fuel consumed by the accessories, which
include
Vehicle
Cooling
System
(VCS),
Climate
Control
System
(CCS),
and
electric
accessories,
is
not
negligible
compared
with
the
fuel
consumed
by
the
vehicle propulsion
system. In addition, the portion of the energy
consumption of
the
accessories
in
HEVs
is
bigger
than
that
of
conventional
vehicles.
This
observation
suggests
that
the
efficient
accessory
system,
particularly
the
VCS
and CCS,
is more important in high-efficiency vehicles
because they have more
effect on the
fuel economy. The effect of the auxiliary load on
the fuel economy
of
high-
efficiency
vehicles
studied
by
Farrington
et
al
[2].
They
examined
the
effect
of
auxiliary
load on
vehicle
fuel
economy
via
a
focus
on
climate
control
system. Figure 2
compares the impact of auxiliary load, i.e. the
power consumed
by
accessory
systems,
on
the
fuel
economy
of
the
conventional
and
high
fuel
economy vehicle. As shown in the
figure, a high fuel economy vehicle is much
more affected by the auxiliary load
than a conventional vehicle. Therefore, more
efficient thermal management systems
including VCS and CCS are essential for
1
外文资料翻译
HEV.
Figure
1.
Energy
flow
for
various
vehicle
configurations.
(A)
ICE,
the
conventional
internal
combustion,
spark
ignition
engine;
(B)
HICE,
a
hybrid
vehicle that includes
an electric motor and parallel drive train which
eliminates
idling loss and captures
some energy of braking [1].]
2
外文资料翻译
Figure
2.
Comparison
of
fuel
economy
impacts
of
auxiliary
loads
between
a
conventional vehicle and a high fuel
economy vehicle [2]
Achieving efficient VCS and CCS for
HEVs requires meeting particular design
challenges
of
the
VCS
and
CCS.
The
design
of
the
VCS
and
CCS
for
HEVs
is
different
from
those
for
conventional
vehicles.
VCS
design
for
HEVs
is
much
more
complicated
than
that
of
conventional
vehicles
because
the
powertrain
of
HEVs
has
additional
powertrain
components.
Furthermore,
the
additional
powertrain
components
are
operated
at
different
temperatures
and
they
are
operated independently of the engine
operation. The design of CCS for HEVs is
also different from that of
conventional vehicles because the temperature of
the
battery pack in HEVs is controlled
by the CCS. Thus, the heat load for the
C
CS
of
HEVs
is
much
higher
than
that
for
the
CCS
of
conventional
vehicles.
Thus,
this is another
challenge for the design of the VTMS for HEVs.
As
noted
above,
these
additional
powertrain
components
such
as
a
generator,
drive
motors,
a
large
battery
pack,
and
a
power
bus
require
proper
thermal
management
to
prevent
thermal
run
away
of
the
power
electronics
used
for
the
3
外文资料翻译
electric
powertrain
components.
Thus,
the
thermal
management
of
the
power
electronics
and
electric
machines
is
one
of
the
challenges
for
the
HEV
development and various studies have
been conducted [3-7]. Generally, dedicated
VCS for the hybrid components are
required as a result of the considerable heat
rejections
and
different
cooling
requirements of the
electric
components.
In the
cooling system of HEVs, a cooling pump
driven by an electric motor, rather than
a
pump
driven
by
the
engine,
is
used
for
the
cooling
circuit
of
the
electric
powertrain
components
because
they
need
cooling
even
when
the
engine
is
turned
off.
The
benefits
of
a
controllable
electric
pump
over
the
mechanical
pump
were
studied
by
Cho
et
al.
[8]
in
the
case
of
the
cooling
system
for
a
medium
duty
diesel
engine.
They
used
numerical
simulations
to
assess
the
fuel
economy
and
cooling
performance
and
it
is
found
that
the
usage
of
an
electric
pump
in
place
of
the
mechanical
pump
can
reduce
power
consumption
by
the
pump and permit
downsizing of the radiator. In addition to those
benefits, the use
of
an
electric
pump
makes
the
configuration
of
the
cooing
circuits
in
hybrid
vehicles relatively
flexible in terms of grouping components in
different circuits.
However, this
flexibility raises an issue in optimizing cooling
circuit architecture
because of the
complexity of the system and the parasitic power
consumption of
the
cooling
system.
The
performance
and
power
consumption
of
the
cooling
system
are
also
very
sensitive
to
the
powertrain
operation.
The
powertrain
operation
is
determined
by
the
power
management
strategy,
which
changes
in
response
to
driving
conditions
of
HEVs.
Therefore,
the
effects
of
driving
conditions must be
considered during the design process of the
cooling system.
Thus, in light of these
additional components, design flexibility, and the
effects
by
vehicle
driving
condition,
it
is
clear
that
the
design
of
the
VCS
for
HEVs
demands
a
strategic
approach
compared
with
the
design
of
the
VCS
for
conventional vehicles.
Another challenge in
designing the VTMS for HEVs is managing the cabin
heat
load generated as a result of the
placement of the battery pack in the passenger
compartment. In HEVs, the battery pack
is located on board because of its lower
4
外文资料翻译
operating
temperature compared with powertrain components.
Therefore, battery
thermal
management
system
is
a
part
of
the
Climate
Control
System
(CCS)
because
the
battery
is
cooled
by
using
the
CCS.
Thus,
the
load
on
the
CCS
of
HEVs
is
higher
than
that
of
conventional
vehicles
because
the
battery
is
the
major
heat
source
in
the
cabin.
In
addition,
battery
thermal
management
is
important
for
the
health
and
life
of
the
battery.
Although
high
temperature
operation
is
better
for
the
battery
performance
due
to
reduced
battery
loss
and
reduced
battery
thermal
management
power,
high
temperature
operation
is
limited due to the
battery durability
and safety. Figure 3
shows the temperatu
re
dependency
of
the
cycle life
of
Liion
battery.
As
can
be
seen
in the
figure,
the
battery life drops
dramatically when the battery is operated at
higher than 60°
C.
The same
happens at lower temperature. In extreme cases,
lithium ion battery can
explode
by
a
chain
reaction.
Generally,
the
battery
operating
temperature
is
limited
lower
than
60°
C
for
the
lithium
ion
and
lead
acid
battery
[9-10].
Accordingly, battery
thermal management associated with climate control
system
is
a
critical
part
of
vehicle
thermal
management
system
design
of
HEVs.
Therefore,
a
comprehensive
vehicle
thermal
management
system
analysis
including
VCS
and
CCS
is
needed
for
the
HEV
vehicle
thermal
management
system design.
5
外文资料翻译
Figure 3. Temperature dependency of the
life cycle of Li-ion battery [11].
Recognizing
the
need
for
the
efficient
vehicle
thermal
management
system
(VTMS)
design
for
HEVs,
many
researchers
have
tried
to
deal
with
the
VTMS
design
for
HEVs
from
various
view-points.
Because
of
the
complexity
and
the
necessity
for the design flexibility of the thermal
management system of HEVs,
numerical
modeling
can
be
an
efficient
way
to
assess
various
design
concepts
and
architectures
of
the
system
during
the
early
stage
of
system
development
compared with
experiments relying on expensive prototype
vehicles. Traci et al.
[12]
demonstrated
that
a
numerical
approach
could
be
successfully
used
for
thermal management
system design of HEVs. They simulated a cooling
system of
an all-electric combat
vehicle that uses a diesel engine as a prime power
source
and
stores
the
power
in
a
central
energy
storage
system.
They
conducted
parametric
studies
on
the
effect
of
the
ambient
temperature
on
the
fan
power
consumption
and
the
effect
of the
coolant
temperature
on
the
system
size. Park
and
Jaura
[13]
used
a
commercial
software
package
to
analyze
the
under-hood
thermal
behavior
of
an
HEV
cooling
system
and
studied
the
effect
of
the
additional
hardware
on
the
performance
of
cooling
system.
They
also
6