Xin Q. Diesel Engine System Design
Подождите немного. Документ загружается.
x Contents
© Woodhead Publishing Limited, 2011
14.13 Cylinder-pressure-based controls 928
14.14 Homogeneous charge compression ignition (HCCI)
controls 928
14.15 References and bibliography 928
15 Diesel engine system specification design and
subsystem interaction 941
15.1 The process of system design analysis 941
15.2 Roadmap of fuel economy improvement 943
15.3 Critical mode design at various ambient conditions 946
15.4 Subsystem interaction and optimization 954
15.5 References and bibliography 969
16 Concluding remarks and outlook for diesel engine
system design 976
Appendix: Statistics summary for probability analysis 983
Index 989
Diesel-Xin-Pre.indd 10 6/2/11 8:41:24 AM
© Woodhead Publishing Limited, 2011
A area
A
c
contact area
A
EGR
the theoretical effective ow area of the EGR valve opening
A
ex
the instantaneous ow area of the engine exhaust valve
A
h
heat transfer area
A
in
the instantaneous ow area of the engine intake valve
A
s
the availability or exergy in the second law of thermo-
dynamics
A
T
turbine effective cross-sectional area
A
V
vehicle frontal area
A
VAL,cyl
the engine valve head area exposed to the cylinder side
A
VAL eff
engine valve effective ow area
A
VAL,port
the engine valve back area exposed to the port side
a acceleration or deceleration
a
˙
jerk
a
amp
acceleration vibration amplitude
a
CAM
cam acceleration
a
e
the long half-axis length of the elliptic contact area
a
V
vehicle acceleration
a
VACL
vibration acceleration level in dB
a
VAL
valve acceleration
B the percentage of fuel energy lost to the base engine coolant
heat rejection
B
E
engine cylinder bore diameter
b width
b
e
half width of Hertzian elliptic contact area
C, C
i
coefcient (i = 1, 2, 3, …), different in each formula
C
c
cost
C
cav
the cavitation factor accounting for the effect of cavitation or
oil lm rupture on friction reduction
C
cf
the cost to functionality if tolerance is exceeded
C
cl
condence level
Nomenclature
Diesel-Xin-Pre.indd 11 6/2/11 8:41:24 AM
© Woodhead Publishing Limited, 2011
C
CMD
Taguchi’s mean square deviation
C
d
the coefcient of ow restriction of an air system valve or a
device/system
C
d,EGR
EGR valve ow restriction coefcient, or the ow restriction
coefficient of the entire EGR circuit (when especially
mentioned)
C
d,exh
total exhaust ow restriction coefcient, including all the
components downstream from the turbine outlet
C
d,int
total intake ow restriction coefcient, including all the
components upstream to the compressor inlet
C
d,IT
intake throttle valve ow restriction coefcient, or the coefcient
of ow restriction of both the intake throttle valve and the
CAC (when especially mentioned)
C
E
engine cylinder-to-cylinder centerline distance
C
f
the coefcient of valve and port ow discharge
C
ij
, C
i,j
coefcient (i = 1, 2, 3, …; j = 1, 2, 3, …), different in each
formula
C
q
quality loss coefcient
C
s
sound coefcient
C
sr
the speed ratio of torque converter
C
T0
the theoretical gas ow velocity in the turbine under the
isentropic condition
C
tr
the torque ratio of torque converter
c clearance or lash
c
B
bearing radial clearance
c
E
engine capacity factor
c
P
piston skirt clearance
c
p
constant-pressure specic heat
c
SC
the clearance of the spring between coils
c
TV
the input capacity factor of torque converter
c
VT
valvetrain lash
c
v
constant-volume specic heat
D damage
D
s
destruction in the second law of thermodynamics
d diameter
d
SC
spring coil diameter
d
SP
spring mean diameter
d
T
turbine wheel average diameter
d
VAL
valve diameter
d
VAL,ref
valve reference diameter
E energy
E
a
activation energy
E
k
kinetic energy
xii Nomenclature
Diesel-Xin-Pre.indd 12 6/2/11 8:41:24 AM
© Woodhead Publishing Limited, 2011
E
k,slap
the kinetic energy of piston slap
E
k,V
vehicle kinetic energy
E
p
potential energy
E
p,V
vehicle potential energy
Ė energy rate or power
e eccentricity or offset
e
1
the lateral distance from cylinder bore centerline to crankshaft
axis (positive value means offset toward the anti-thrust side
of the piston)
e
2
the lateral distance from piston centerline to piston pin (positive
value means offset toward the anti-thrust side of the piston)
F force
F (…) the constrained single-objective function in multi-objective
optimization
F
a
vehicle aerodynamic drag resistance force
F
acc
the resistance force acting on the vehicle wheels caused by
vehicle accessory loads
F
amp
force vibration amplitude
F
br
the force of the service brakes (wheel brakes) acting on the
vehicle wheels
F
df
the drivetrain friction force acting on the vehicle wheels
F
dr
the resistance force of drivetrain retarders acting on the
vehicle
F
er
the engine brake retarding force acting on the vehicle
wheels
F
f
friction force
F
f,stem
valve stem friction force
F
f,v
viscous friction force
F
gas
gas loading (force)
F
gas,VAL
the net gas loading acting on the valve
F
gl
the gravity force on a gradient acting on the vehicle wheels along
the longitudinal direction (i.e., along the road direction)
F
i
the vehicle inertia force along the longitudinal direction
F
lub,an
the lubricant force acting on the anti-thrust side of the piston
skirt in the normal direction
F
lub,th
the lubricant force acting on the thrust side of the piston skirt
in the normal direction
F
n
the force or load acting in the normal direction
F
pre
valve spring preload force
F
rf
vehicle tire–road rolling friction resistance force
F
rt
piston ring tension
F
SP
spring force (load)
F
t
the vehicle tractive force from engine ring acting on the
wheels
xiiiNomenclature
Diesel-Xin-Pre.indd 13 6/2/11 8:41:24 AM
© Woodhead Publishing Limited, 2011
F
groove
the lateral friction force between the ring and the ring groove
per unit length of the piston ring
F
lub
the lubricating oil film force per unit length of the
component
F
lub,ring
the lubricating oil lm force per unit length of the piston
ring
F
n
the normal loading force per unit length
F
tension
the tension force per unit length of the piston ring
f (…) function or objective function
f
R
a percentile of the function f (...)
f
a
the coef cient of aerodynamic resistance
f
adp
the coef cient of adaptability
f
adh
the coef cient of road adhesion
f
A/F
engine air–fuel ratio
f
A/F,stoi
stoichiometric air–fuel ratio
f
b
the coef cient of engine torque backup
f
C-C
the ratio of connecting rod length to crank radius (i.e., conrod–
crank ratio)
f
CAM,ac
the coef cient of cam acceleration pulse width
f
CAM,lub
the coef cient of cam lubrication characteristics
f
CDF
cumulative distribution function
f
cm
cooling capability multiplier for ow rate
f
cor
the coef cient of restitution
f
cov
the coef cient of variation
f
ce
cooling capability multiplier for effectiveness
f
dd
the dynamic de ection factor of the valvetrain
f
EGR
EGR rate
f
f
feasibility of increasing a component’s reliability
f
fail
failure rate
f
fri
the coef cient of friction
f
hu
humidity
f
iEGR
internal residue fraction or internal EGR rate
f
lift
the coef cient of the roundness of the valve lift
f
NTU
the number of transfer units in heat exchangers
f
n
natural frequency
f
n,SP
valve spring natural frequency (as distributed mass)
f
O
2
oxygen mass fraction
f
O
2
,air
the mass fraction of O
2
(oxygen) in the ambient air
f
O
2
,IM
the mass fraction of O
2
(oxygen) in the intake manifold
charge
f
ova
the degree of ovality of the piston skirt
f
PDF
probability density function
f
pr
pressure ratio
xiv Nomenclature
Diesel-Xin-Pre.indd 14 6/2/11 8:41:25 AM
© Woodhead Publishing Limited, 2011
f
ql
cyclic loading frequency
f
q
frequency
f
r
fraction
f
RA
rocker arm ratio
f
rf
the coefcient of rolling friction resistance
f
ri
the coefcient of rated intensity
f
rpr
the rate of cylinder pressure rise
f
RMSE%
the percentage of root-mean-square error
f
sd
the static deection factor of the valvetrain
f
sf
safety factor
f
slip
tire slip
f
sr
the coefcient of speed reserve
f
S/N
signal-to-noise ratio
f
swr
swirl ratio
f
v
(...) the variance of objective function f (...)
f
w
wear coefcient
f
Wahl
the Wahl stress correction factor for springs
f
x
mole fraction
G the percentage of fuel energy lost to miscellaneous heat
losses
G
G
Gibbs free enthalpy
G
r
road grade
g the acceleration due to gravity
g (…) constraint function in optimization
H enthalpy
H
˙
exh,ring
the exhaust enthalpy rate in the ring operation
H
˙
exh,retarding
the exhaust enthalpy rate in the retarding operation
h specic enthalpy, or in-cylinder gas specic enthalpy
h
o
lubricating oil lm thickness
h
r
hazard function in reliability engineering
h
w
the penetration hardness of surface in wear
h1,h2, h3, h4 the clearance or oil lm thickness at the four corners of the
piston skirt in the piston thrust plane
I moment of inertia
I
drive
vehicle driveline moment of inertia
I
E
engine moment of inertia
I
irr
irreversibility in the second law of thermodynamics
I
R
reliability importance
I
RA
the moment of inertia of the rocker arm
I
s
sound intensity
I
SIL
sound intensity level in dB
I
TC
the moment of inertia of the turbocharger
i index number
xvNomenclature
Diesel-Xin-Pre.indd 15 6/2/11 8:41:25 AM
© Woodhead Publishing Limited, 2011
i
ax
axle ratio
i
F
the indicator of front geartrain or rear geartrain
i
gr
transmission gear ratio
i
grn
transmission gear number
J torque
J
E
engine brake torque
J
E,r
the engine retarding brake torque acting on the crankshaft
J
f
friction torque
j index number
k reaction constant, or other constant
k
h
overall heat transfer coefcient
k
s
the stiffness of a component or physical system
k
s,SP
spring rate (stiffness)
k
s,VAL
valve or valve stem stiffness
k
s,VT
overall valvetrain stiffness
k the total number of DoE factors
k
c
thermal conductivity
k
r
reaction rate
k
v
viscous friction coefcient
L length (of pipe or component, etc.), or the width of the component
in the direction of motion
L
B
bearing length
L
CG,P
the vertical distance from the piston center of gravity to the
top of the piston skirt (positive value means the piston center
of gravity is located below the top of the piston skirt, and a
larger positive value means a lower position of the piston
center of gravity)
L
clear
the clearance height in the cylinder and the combustion
chamber
L
q
quality loss
l displacement, travel distance, or lift
l
a
altitude level
l
a,V
the altitude level for the vehicle
l
CAM
cam lift
l
CAM,ramp
cam ramp height as a function of cam angle
l
RA
rocker arm length
l
r,V
vehicle braking distance
l
SP
spring length
l
V
vehicle travel distance
l
VAL
valve lift
l
VAL,design
the valve lift at the “design speed” of the valvetrain
l
VAL,max
maximum valve lift
l
VDL
vibration displacement level in dB
xvi Nomenclature
Diesel-Xin-Pre.indd 16 6/2/11 8:41:25 AM
© Woodhead Publishing Limited, 2011
l
w,sl
sliding distance in wear
M moment
M
a
Mach number
m mass, or in-cylinder gas mass, or the total number of index
m (…) equality constraint functions in optimization
m
E,mov
the engine assembly mass of the moving parts
m
fuel
the consumed fuel mass
m
fuelB
the fuel mass injected into the cylinder
m
fuelC
the total injected fuel mass per engine cycle
m
J
journal mass
m
P
piston mass
m
V
total vehicle mass
m
VAL
valve mass
m
VT
valvetrain equivalent mass
m
mass ow rate
m
air
engine fresh air mass ow rate
m
EGR
EGR mass ow rate
m
ex
the engine exhaust gas mass ow rate at the turbine inlet or in
the exhaust manifold or port (Note: This parameter is affected
by EGR pickup.)
m
exh
the engine exhaust gas mass ow rate at the turbine outlet
m
fuel
fuel mass ow rate
m
T
actual turbine mass ow rate
m
WG
turbine wastegate mass ow rate
m
~
AT
precious metal loading in aftertreatment
m
~
ring
the mass of the piston ring per unit length of the ring
N speed
N
B
journal bearing rotational speed
N
C
compressor shaft speed
N
design
valvetrain design speed
N
E
engine crankshaft rotational speed
N
f
the number of loading cycle to reach failure
N
T
turbine shaft speed
N
TC
turbocharger speed
N
u
the Nusselt number
N
V
vehicle speed
N
Vw
the vehicle speed relative to the wind
n the total number of index, or the number of DoE runs, or sample
size (number of samples), or the number of grid points, etc.
n
c
combustion index for noise
n
E
the number of engine cylinders
n
G
the number of gear meshes between the crankshaft and the
fuel system
xviiNomenclature
Diesel-Xin-Pre.indd 17 6/2/11 8:41:25 AM
© Woodhead Publishing Limited, 2011
n
l
the number of loading cycle
n
SC
the number of spring coils
n
s
the number of crankshaft revolutions in one engine cycle
n
sm
smoke number
n
VAL
the number of engine valves
O valve, throttle, wastegate, or vane opening; or pedal position
O
a
opening area
O
ang
opening angle
O
dia
opening diameter
P probability
P
fail
the probability of failure
P
r
the Prandtl number
p pressure, or in-cylinder gas pressure, or the number of regression
coefcients in the emulator model in DoE
p
asperity
the asperity contact pressure in the mixed or boundary
lubrication
p
comp
in-cylinder compression pressure
p
cyl
cylinder pressure
p
EM
, p
3
exhaust manifold pressure
p
ex
exhaust port pressure
p
IM
, p
2a
intake manifold boost pressure
p
in
intake port pressure
p
inj
fuel injection pressure
p
l
the loading pressure acting on the sliding component, or the
mean Hertzian contact pressure
p
lub
lubricating oil lm pressure
p
max
peak cylinder gas pressure
p
port
port pressure
p
s
sound pressure
p
SPL
sound pressure level in dB
p
SPL,E
overall engine noise sound pressure level
Q heat, or the heat exchanged through the system boundary
Q
˙
heat transfer rate (i.e., heat rejection)
Q
fuel
fuel energy
Q
wall
the heat transfer through the walls of the cylinder head, the
piston, and the liner
Q
˙
base-coolant
the heat rejection from the base engine to the coolant
Q
˙
hrj,firing
the engine coolant heat rejection in the ring operation
Q
˙
hrj,retarding
the unrecoverable heat dissipation to the cooling system in the
retarding operation
Q
˙
miscellaneous
miscellaneous heat losses
q heat per unit of mass, or the total number of objective functions
in multi-objective optimization
xviii Nomenclature
Diesel-Xin-Pre.indd 18 6/2/11 8:41:25 AM
© Woodhead Publishing Limited, 2011
q
LHV
the lower heating value of the fuel
q
heat ux
R reliability
R
adj
2
the adjusted coef cient of determination
R
d
2
the coef cient of determination
R
pr
edictio
n
2
the coef cient of predicted variation
R
e
the Reynolds number
R
ex
the speci c gas constant of exhaust gas
R
gas
speci c gas constant
R
i
the reliability of component i or subsystem i
R
in
the speci c gas constant of intake charge
R
N
the number of repairs
R
S
system reliability
r radius, or index number
r
B
bearing radius
r
ROC
the radius of curvature
r
tire
tire dynamic radius
S material strength
S
E
engine stroke
S
e
entropy
S
E
/B
E
engine stroke-to-bore ratio
S
lub
lubrication duty parameter
S
lub,sr
lubrication parameter
S
ODE
the stiffness ratio of ODE system
S
SE
, S
SR
, S
ST
statistical functions in response surface methodology (RSM)
s stress
s
e
speci c entropy
s
fl
fatigue limit stress
s
SP
the torsional stress of the spring
s
u
ultimate stress
T temperature, or in-cylinder gas temperature
T
CACout
the air or gas temperature at the CAC outlet (before EGR
mixing)
T
ch
characteristic temperature
T
EGR
the EGR gas temperature at the EGR cooler outlet
T
ex
exhaust port gas temperature
T
f
the required time to reach creep failure
T
flash
ash temperature
T
in
intake port gas temperature
T
sink
cooling medium inlet temperature, i.e., the sink temperature
T
wall
the component metal temperature at the wall
T
1,ROA
compressor inlet temperature including the rise-over-ambient
(ROA) effect
xixNomenclature
Diesel-Xin-Pre.indd 19 6/2/11 8:41:26 AM