CI Core Engine
Compressionignition engine from intake to exhaust port
Description
The CI Core Engine block implements a compressionignition
(CI) engine from intake to the exhaust port. You can use the block
for hardwareintheloop (HIL) engine control design or vehiclelevel
fuel economy and performance simulations.
The CI Core Engine block calculates:
Air Mass Flow
To calculate the air mass flow, the compressionignition (CI)
engine uses the CI Engine SpeedDensity Air Mass Flow Model. The speeddensity
model uses the speeddensity equation to calculate the engine air
mass flow, relating the engine intake port mass flow to the intake
manifold pressure, intake manifold temperature, and engine speed.
Brake Torque
To calculate the engine torque, you can configure the block to
use either of these torque models.
Brake Torque Model  Description 

CI Engine Torque Structure Model 
The CI core engine torque structure model determines the engine
torque by reducing the maximum engine torque potential as these engine conditions vary from nominal:
Start of injection (SOI) timing Exhaust backpressure Burned fuel mass Intake manifold gas pressure, temperature, and oxygen percentage Fuel rail pressure
To account for the effect of postinject fuel on torque, the model uses a
calibrated torque offset table.

CI Engine Simple Torque Model  For the simple engine torque calculation, the CI
engine uses a torque lookup table map that is a function of engine speed
and injected fuel mass. 
Fuel Flow
In the CI Core Engine and CI
Controller blocks, you can represent multiple injections with the start of injection
(SOI) and fuel mass inputs to the model. To specify the type of injection, use the
Fuel mass injection type identifier parameter.
Type of Injection  Parameter Value 

Pilot  0

Main  1

Post  2

Passed  3

The model considers Passed
fuel injections and fuel injected
later than a threshold to be unburned fuel. Use the Maximum start of injection angle
for burned fuel, f_tqs_f_burned_soi_limit parameter to specify the
threshold.
To calculate the engine fuel mass flow, the CI Core
Engine block uses fuel mass flow delivered by the injectors and the engine airflow.
To calculate the fuel economy for highfidelity models, the block uses the
volumetric fuel flow.
The equation uses these variables.
${\dot{m}}_{fuel}$  Fuel mass flow, g/s 
m_{fuel,inj}  Fuel mass per injection 
$$Cps$$  Crankshaft revolutions per power stroke, rev/stroke 
${N}_{cyl}$  Number of engine cylinders 
N  Engine speed, rpm 
Q_{fuel}  Volumetric fuel flow 
Sg_{fuel}  Specific gravity of fuel 
AirFuel Ratio
To calculate the airfuel (AFR) ratio, the CI Core
Engine and SI Core Engine blocks implement this equation.
The CI Core Engine uses this equation to calculate the
relative AFR.
To calculate the exhaust gas recirculation (EGR), the blocks implement this
equation. The calculation expresses the EGR as a percent of the total intake port flow.
The equations use these variables.
$AFR$  Airfuel ratio 
AFR_{s}  Stoichiometric airfuel ratio 
${\dot{m}}_{intk}$  Engine air mass flow 
${\dot{m}}_{fuel}$  Fuel mass flow 
λ  Relative AFR 
y_{intk,b}  Intake burned mass fraction 
EGR_{pct}  EGR percent 
${\dot{m}}_{intk,b}$  Recirculated burned gas mass flow rate 
Exhaust Temperature
The exhaust temperature calculation depends on the torque model. For both torque models, the block implements lookup tables.
Torque Model  Description  Equations 

Simple Torque Lookup
 Exhaust temperature lookup table is a function of the injected fuel mass and engine speed. 

Torque Structure 
The nominal exhaust temperature,
Texh_{nom}, is a product of these exhaust
temperature efficiencies:
SOI timing Intake manifold gas pressure Intake manifold gas temperature Intake manifold gas oxygen percentage Fuel rail pressure Optimal temperature
The exhaust temperature, Texh_{nom}, is
offset by a post temperature effect, ΔT_{post}, that
accounts for post and late injections during the expansion and exhaust strokes. 

The equations use these variables.
F  Compression stroke injected fuel mass 
N  Engine speed 
Texh  Exhaust manifold gas temperature 
Texh_{opt}  Optimal exhaust manifold gas temperature 
ΔT_{post}  Post injection temperature effect 
Texh_{nom}  Nominal exhaust temperature 
SOI_{exhteff}  Main SOI exhaust temperature efficiency multiplier 
ΔSOI  Main SOI timing relative to optimal timing 
MAP_{exheff}  Intake manifold gas pressure exhaust temperature efficiency multiplier 
MAP_{ratio}  Intake manifold gas pressure ratio relative to optimal pressure ratio 
λ  Intake manifold gas lambda 
MAT_{exheff}  Intake manifold gas temperature exhaust temperature efficiency multiplier 
ΔMAT  Intake manifold gas temperature relative to optimal temperature 
O2P_{exheff}  Intake manifold gas oxygen exhaust temperature efficiency multiplier 
ΔO2P  Intake gas oxygen percent relative to optimal 
FUELP_{exheff}  Fuel rail pressure exhaust temperature efficiency multiplier 
ΔFUELP  Fuel rail pressure relative to optimal 
EO Exhaust Emissions
The block calculates these engineout (EO) exhaust emissions:
The exhaust temperature determines the specific enthalpy.
The exhaust mass flow rate is the sum of the intake port air
mass flow and the fuel mass flow.
To calculate the exhaust emissions, the block multiplies the
emission mass fraction by the exhaust mass flow rate. To determine
the emission mass fractions, the block uses lookup tables that are
functions of the engine torque and speed.
The fraction of air and fuel entering the intake port, injected
fuel, and stoichiometric AFR determine the air mass fraction that
exits the exhaust.
If the engine is operating at the stoichiometric or fuel rich
AFR, no air exits the exhaust. Unburned hydrocarbons and burned gas
comprise the remainder of the exhaust gas. This equation determines
the exhaust burned gas mass fraction.
The equations use these variables.
${T}_{exh}$  Engine exhaust temperature 
${h}_{exh}$  Exhaust manifold inletspecific enthalpy 
$C{p}_{exh}$  Exhaust gas specific heat 
${\dot{m}}_{intk}$  Intake port air mass flow rate 
${\dot{m}}_{fuel}$  Fuel mass flow rate 
$${\dot{m}}_{exh}$$  Exhaust mass flow rate 
$${y}_{in,fuel}$$  Intake fuel mass fraction 
y_{exh,i}  Exhaust mass fraction for i = CO_{2}, CO, HC, NOx, air, burned gas, and
PM 
$${\dot{m}}_{exh,i}$$  Exhaust mass flow rate for i = CO_{2}, CO, HC, NOx, air, burned gas, and
PM 
T_{brake}  Engine brake torque 
N  Engine speed 
y_{exh,air}  Exhaust air mass fraction 
y_{exh,b}  Exhaust air burned mass fraction 
Power Accounting
For the power accounting, the block implements equations that depend on Torque model.
When you set Torque model to Simple Torque Lookup
, the block implements these equations.
Bus Signal  Description  Equations 

PwrInfo
 PwrTrnsfrd — Power transferred between blocks
 PwrIntkHeatFlw
 Intake heat flow  ${\dot{m}}_{intk}{h}_{intk}$ 
PwrExhHeatFlw  Exhaust heat flow  ${\dot{m}}_{exh}{h}_{exh}$ 
PwrCrkshft  Crankshaft power  ${T}_{brake}\omega $ 
PwrNotTrnsfrd — Power crossing the block
boundary, but not transferred
 PwrFuel  Fuel input power  ${\dot{m}}_{fuel}LHV$ 
PwrLoss  All losses  ${T}_{brake}\omega {\dot{m}}_{fuel}LHV{\dot{m}}_{intk}{h}_{intk}+{\dot{m}}_{exh}{h}_{exh}$ 
PwrStored — Stored energy rate of change
 Not used 
When you set Torque model to Torque Structure
, the block implements these equations.
Bus Signal  Description  Equations 

PwrInfo
 PwrTrnsfrd — Power transferred between blocks
 PwrIntkHeatFlw
 Intake heat flow  ${\dot{m}}_{intk}{h}_{intk}$ 
PwrExhHeatFlw  Exhaust heat flow  ${\dot{m}}_{exh}{h}_{exh}$ 
PwrCrkshft  Crankshaft power  ${T}_{brake}\omega $ 
PwrNotTrnsfrd — Power crossing the block
boundary, but not transferred
 PwrFuel  Fuel input power  ${\dot{m}}_{fuel}LHV$ 
PwrFricLoss  Friction loss  ${T}_{fric}\omega $ 
PwrPumpLoss  Pumping loss  ${T}_{pump}\omega $ 
PwrHeatTrnsfrLoss  Heat transfer loss  ${T}_{brake}\omega {\dot{m}}_{fuel}LHV{\dot{m}}_{intk}{h}_{intk}+{\dot{m}}_{exh}{h}_{exh}+{T}_{fric}\omega +{T}_{pump}\omega $ 
PwrStored — Stored energy rate of change
 Not used 
h_{exh}  Exhaust manifold inletspecific enthalpy 
h_{intk}  Intake port specific enthalpy 
${\dot{m}}_{intk}$  Intake port air mass flow rate 
${\dot{m}}_{fuel}$  Fuel mass flow rate 
$${\dot{m}}_{exh}$$  Exhaust mass flow rate 
ω  Engine speed 
T_{brake}  Brake torque 
T_{pump}  Engine pumping torque offset to inner torque 
T_{fric}  Engine friction torque 
LHV  Fuel lower heating value 
Ports
Input
expand all
FuelMass
— Fuel injector pulsewidth
vector
Fuel mass per injection,
m_{fuel,inj}, in
mg per injection.
Soi
— Start of fuel injection timing
vector
Fuel injection timing, SOI, in degrees crank angle
after top dead center (degATDC). First vector value,
Soi(1)
, is main injection timing.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
EngSpd
— Engine speed
scalar
FuelPrs
— Fuel rail pressure
scalar
Fuel rail pressure, FUELP, in MPa.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Ect
— Engine cooling temperature
scalar
Engine cooling temperature,
T_{coolant}, in K.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intk
— Intake port pressure, temperature, enthalpy, mass fractions
twoway connector port
Bus containing the upstream:
Prs
— Pressure, in Pa
Temp
— Temperature, in K
Enth
— Specific enthalpy,
in J/kg
MassFrac
—
Intake port mass fractions, dimensionless. Exhaust gas recirculation
(EGR) mass flow at the intake port is burned gas.
Specifically, a bus with these mass fractions:
O2MassFrac
— Oxygen
N2MassFrac
— Nitrogen
UnbrndFuelMassFrac
— Unburned fuel
CO2MassFrac
— Carbon dioxide
H2OMassFrac
— Water
COMassFrac
— Carbon monoxide
NOMassFrac
— Nitric oxide
NO2MassFrac
— Nitrogen dioxide
NOxMassFrac
— Nitric oxide and nitrogen dioxide
PmMassFrac
— Particulate matter
AirMassFrac
— Air
BrndGasMassFrac
— Burned gas
Exh
— Exhaust port pressure, temperature, enthalpy, mass fractions
twoway connector port
Bus containing the exhaust:
Prs
— Pressure, in Pa
Temp
— Temperature, in K
Enth
— Specific enthalpy,
in J/kg
MassFrac
—
Exhaust port mass fractions, dimensionless.
Specifically, a bus with these mass fractions:
O2MassFrac
— Oxygen
N2MassFrac
— Nitrogen
UnbrndFuelMassFrac
— Unburned fuel
CO2MassFrac
— Carbon dioxide
H2OMassFrac
— Water
COMassFrac
— Carbon monoxide
NOMassFrac
— Nitric oxide
NO2MassFrac
— Nitrogen dioxide
NOxMassFrac
— Nitric oxide and nitrogen dioxide
PmMassFrac
— Particulate matter
AirMassFrac
— Air
BrndGasMassFrac
— Burned gas
Output
expand all
Info
— Bus signal
bus
Bus signal containing these block calculations.
Signal  Description  Variable  Units 

IntkGasMassFlw
 Engine intake air mass flow.  ${\dot{m}}_{air}$  kg/s 
IntkAirMassFlw
 Engine intake port mass
flow.  ${\dot{m}}_{intk}$  kg/s 
NrmlzdAirChrg
 Engine load (that is, normalized cylinder
air mass) corrected for final steadystate cam
phase angles  $L$  N/A 
Afr
 Airfuel ratio at engine exhaust
port  $AFR$  N/A 
FuelMassFlw
 Fuel flow into engine  ${\dot{m}}_{fuel}$  kg/s 
FuelVolFlw
 Volumetric fuel flow  Q_{fuel}  m^{3}/s 
ExhManGasTemp
 Exhaust gas temperature at exhaust manifold
inlet  ${T}_{exh}$  K 
EngTrq
 Engine brake torque  ${T}_{brake}$  N·m 
EngSpd
 Engine speed  $N$  rpm 
IntkCamPhase
 Intake cam phaser angle  ${\phi}_{ICP}$ i  degrees crank advance 
ExhCamPhase
 Exhaust cam phaser angle  ${\phi}_{ECP}$  degrees crank retard 
CrkAng
 Engine crankshaft absolute
angle  $$\underset{0}{\overset{(360)Cps}{\int}}EngSpd\frac{180}{30}d\theta$$ where $$Cps$$ is crankshaft revolutions per
power stroke  degrees crank angle 
EgrPct
 EGR percent  EGR_{pct}  N/A 
EoAir
 EO air mass flow rate  $${\dot{m}}_{exh}$$  kg/s 
EoBrndGas
 EO burned gas mass flow rate  y_{exh,b}  kg/s 
EoHC
 EO hydrocarbon emission mass flow
rate  y_{exh,HC}  kg/s 
EoCO
 EO carbon monoxide emission mass flow
rate  y_{exh,CO}  kg/s 
EoNOx
 EO nitric oxide and nitrogen dioxide
emissions mass flow rate  y_{exh,NOx}  kg/s 
EoCO2
 EO carbon dioxide emission mass flow
rate  y_{exh,CO2}  kg/s 
EoPm
 EO particulate matter emission mass flow
rate  y_{exh,PM}  kg/s 
PwrInfo  PwrTrnsfrd  PwrIntkHeatFlw
 Intake heat flow  ${\dot{m}}_{intk}{h}_{intk}$  W 
PwrExhHeatFlw  Exhaust heat flow  ${\dot{m}}_{exh}{h}_{exh}$  W 
PwrCrkshft  Crankshaft power  ${T}_{brake}\omega $  W 
PwrNotTrnsfrd  PwrFuel  Fuel input power  ${\dot{m}}_{fuel}LHV$  W 
PwrLoss  For Torque model set
to Simple Torque
Lookup : All
losses  ${T}_{brake}\omega {\dot{m}}_{fuel}LHV{\dot{m}}_{intk}{h}_{intk}+{\dot{m}}_{exh}{h}_{exh}$  W 
PwrFricLoss  For Torque model set
to Torque
Structure : Friction
loss  ${T}_{fric}\omega $  W 
PwrPumpLoss  For Torque model set
to Torque
Structure : Pumping
loss  ${T}_{pump}\omega $  W 
PwrHeatTrnsfrLoss  For Torque model set
to Torque
Structure : Heat transfer
loss  ${T}_{brake}\omega {\dot{m}}_{fuel}LHV{\dot{m}}_{intk}{h}_{intk}+{\dot{m}}_{exh}{h}_{exh}+{T}_{fric}\omega +{T}_{pump}\omega $  W 
PwrStored  Not
used 
EngTrq
— Engine brake torque
scalar
Engine brake torque, ${T}_{brake}$, in N·m.
Intk
— Intake port mass flow rate, heat flow rate, temperature, mass fraction
twoway connector port
Bus containing:
MassFlwRate
— Intake port
mass flow rate, in kg/s
HeatFlwRate
— Intake port
heat flow rate, in J/s
ExhManGasTemp
— Intake port
temperature, in K
MassFrac
—
Intake port mass fractions, dimensionless.
Specifically, a bus with these mass fractions:
O2MassFrac
— Oxygen
N2MassFrac
— Nitrogen
UnbrndFuelMassFrac
— Unburned fuel
CO2MassFrac
— Carbon dioxide
H2OMassFrac
— Water
COMassFrac
— Carbon monoxide
NOMassFrac
— Nitric oxide
NO2MassFrac
— Nitrogen dioxide
NOxMassFrac
— Nitric oxide and nitrogen dioxide
PmMassFrac
— Particulate matter
AirMassFrac
— Air
BrndGasMassFrac
— Burned gas
Exh
— Exhaust port mass flow rate, heat flow rate, temperature, mass fraction
twoway connector port
Bus containing:
MassFlwRate
— Exhaust port
mass flow rate, in kg/s
HeatFlwRate
— Exhaust heat
flow rate, in J/s
ExhManGasTemp
— Exhaust
port temperature, in K
MassFrac
—
Exhaust port mass fractions, dimensionless.
Specifically, a bus with these mass fractions:
O2MassFrac
— Oxygen
N2MassFrac
— Nitrogen
UnbrndFuelMassFrac
— Unburned fuel
CO2MassFrac
— Carbon dioxide
H2OMassFrac
— Water
COMassFrac
— Carbon monoxide
NOMassFrac
— Nitric oxide
NO2MassFrac
— Nitrogen dioxide
NOxMassFrac
— Nitric oxide and nitrogen dioxide
PmMassFrac
— Particulate matter
AirMassFrac
— Air
BrndGasMassFrac
— Burned gas
Parameters
expand all
Block Options
Torque model
— Select torque model
Torque Structure
(default)  Simple Torque Lookup
To calculate the engine torque, you can configure the block to
use either of these torque models.
Brake Torque Model  Description 

CI Engine Torque Structure Model 
The CI core engine torque structure model determines the engine
torque by reducing the maximum engine torque potential as these engine conditions vary from nominal:
Start of injection (SOI) timing Exhaust backpressure Burned fuel mass Intake manifold gas pressure, temperature, and oxygen percentage Fuel rail pressure
To account for the effect of postinject fuel on torque, the model uses a
calibrated torque offset table.

CI Engine Simple Torque Model  For the simple engine torque calculation, the CI
engine uses a torque lookup table map that is a function of engine speed
and injected fuel mass. 
Air
Number of cylinders, NCyl
— Engine cylinders
scalar
Number of engine cylinders, ${N}_{cyl}$.
Crank revolutions per power stroke, Cps
— Revolutions per stroke
scalar
Crankshaft revolutions per power stroke, $$Cps$$, in rev/stroke.
Total displaced volume, Vd
— Volume
scalar
Displaced volume, ${V}_{d}$, in m^3.
Ideal gas constant air, Rair
— Constant
scalar
Ideal gas constant, ${R}_{air}$, in J/(kg·K).
Air standard pressure, Pstd
— Pressure
scalar
Standard air pressure, ${P}_{std}$, in Pa.
Speeddensity volumetric efficiency, f_nv
— Lookup table
array
The volumetric efficiency lookup table
is a function of the intake manifold absolute pressure at intake valve
closing (IVC) and engine speed
where:
${\eta}_{v}$ is
engine volumetric efficiency, dimensionless.
MAP is intake manifold absolute
pressure, in KPa.
N is engine speed, in rpm.
Speeddensity intake manifold pressure breakpoints, f_nv_prs_bpt
— Breakpoints
array
Intake manifold pressure breakpoints for speeddensity volumetric
efficiency lookup table, in KPa.
Speeddensity engine speed breakpoints, f_nv_n_bpt
— Breakpoints
array
Engine speed breakpoints for speeddensity volumetric efficiency
lookup table, in rpm.
Torque
Torque  Simple Torque Lookup
Torque table, f_tq_nf
— Lookup table
array
For the simple torque lookup table model, the CI engine uses
a lookup table is a function of engine speed and injected fuel mass, ${T}_{brake}={f}_{Tnf}(F,N)$,
where:
Tq = T_{brake} is
engine brake torque after accounting for engine mechanical and pumping
friction effects, in N·m.
F is injected fuel mass, in mg
per injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Simple Torque Lookup
.
Torque table fuel mass per injection breakpoints, f_tq_nf_f_bpt
— Breakpoints
vector
Torque table fuel mass per injection breakpoints, in mg per injection.
Dependencies
To enable this parameter, for Torque model, select
Simple Torque Lookup
.
Torque table speed breakpoints, f_tq_nf_n_bpt
— Breakpoints
vector
Engine speed breakpoints, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Simple Torque Lookup
.
Torque  Torque Structure
Fuel mass per injection breakpoints, f_tqs_f_bpt
— Breakpoints
vector
Fuel mass per injection breakpoints, in mg per injection.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Engine speed breakpoints, f_tqs_n_bpt
— Breakpoints
vector
Engine speed breakpoints, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Optimal main start of injection timing, f_tqs_mainsoi
— Optimal MAINSOI
array
The optimal main start of injection (SOI) timing lookup table,
ƒ_{SOIc}, is a function of the engine speed and
injected fuel mass, SOI_{c} =
ƒ_{SOIc}(F,N), where:
SOI_{c} is optimal SOI timing, in
degATDC.
F is compression stroke injected fuel mass, in mg per
injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Optimal intake manifold gas pressure, f_tqs_map
— Optimal intake MAP
array
The optimal intake manifold gas pressure lookup table,
ƒ_{MAP}, is a function of the engine speed and
injected fuel mass, MAP = ƒ_{MAP}(F,N), where:
MAP is optimal intake manifold gas pressure, in Pa.
F is compression stroke injected fuel mass, in mg per
injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Optimal exhaust manifold gas pressure, f_tqs_emap
— Optimal exhaust MAP
array
The optimal exhaust manifold gas pressure lookup table,
ƒ_{EMAP}, is a function of the engine speed and
injected fuel mass, EMAP = ƒ_{EMAP}(F,N), where:
EMAP is optimal exhaust manifold gas pressure, in Pa.
F is compression stroke injected fuel mass, in mg per
injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Optimal intake manifold gas temperature, f_tqs_mat
— Optimal intake MAT
array
The optimal intake manifold gas temperature lookup table,
ƒ_{MAT}, is a function of the engine speed and
injected fuel mass, MAT = ƒ_{MAT}(F,N), where:
MAT is optimal intake manifold gas temperature, in K.
F is compression stroke injected fuel mass, in mg per
injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Optimal intake gas oxygen percent, f_tqs_o2pct
— Optimal intake gas oxygen
array
The optimal intake gas oxygen percent lookup table,
ƒ_{O2}, is a function of the engine speed and
injected fuel mass, O2PCT = ƒ_{O2}(F,N), where:
O2PCT is optimal intake gas oxygen, in percent.
F is compression stroke injected fuel mass, in mg per
injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Optimal fuel rail pressure, f_tqs_fuelpress
— Optimal fuel rail pressure
array
The optimal fuel rail pressure lookup table,
ƒ_{fuelp}, is a function of the engine speed and
injected fuel mass, FUELP = ƒ_{fuelp}(F,N), where:
FUELP is optimal fuel rail pressure, in MPa.
F is compression stroke injected fuel mass, in mg per
injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Optimal gross indicated mean effective pressure, f_tqs_imepg
— Optimal mean effective pressure
array
The optimal gross indicated mean effective pressure lookup
table, ƒ_{imepg}, is a function of the engine speed and
injected fuel mass, IMEPG = ƒ_{imepg}(F,N), where:
IMEPG is optimal gross indicated mean effective pressure, in
Pa.
F is compression stroke injected fuel mass, in mg per
injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Optimal friction mean effective pressure, f_tqs_fmep
— Optimal friction mean effective pressure
array
The optimal friction mean effective pressure lookup table,
ƒ_{fmep}, is a function of the engine speed and
injected fuel mass, FMEP = ƒ_{fmep}(F,N), where:
FMEP is optimal friction mean effective pressure, in Pa.
F is compression stroke injected fuel mass, in mg per
injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Optimal pumping mean effective pressure, f_tqs_pmep
— Optimal pumping mean effective pressure
array
The optimal pumping mean effective pressure lookup table,
ƒ_{pmep}, is a function of the engine speed and
injected fuel mass, PMEP = ƒ_{pmep}(F,N), where:
PMEP is optimal pumping mean effective pressure, in Pa.
F is compression stroke injected fuel mass, in mg per
injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Friction multiplier as a function of temperature, f_tqs_fric_temp_mod
— Friction multiplier
array
Friction multiplier as a function of temperature, dimensionless.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Friction multiplier temperature breakpoints, f_tqs_fric_temp_bpt
— Breakpoints
vector
Friction multiplier temperature breakpoints, in K.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Main start of injection timing efficiency multiplier, f_tqs_mainsoi_eff
— MAINSOI efficiency multiplier
array
The main start of injection (SOI) timing efficiency multiplier
lookup table, ƒ_{SOIeff}, is a function of the engine
speed and main SOI timing relative to optimal timing, SOI_{eff} =
ƒ_{SOIeff}(ΔSOI,N), where:
SOI_{eff} is main SOI timing efficiency
multiplier, dimensionless.
ΔSOI is main SOI timing relative to optimal timing, in
degBTDC.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Main start of injection timing relative to optimal timing breakpoints, f_tqs_mainsoi_delta_bpt
— Breakpoints
vector
Main start of injection timing relative to optimal timing breakpoints, in
degBTDC.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intake manifold gas pressure efficiency multiplier, f_tqs_map_eff
— Intake pressure efficiency multiplier
array
The intake manifold gas pressure efficiency multiplier lookup
table, ƒ_{MAPeff}, is a function of the intake manifold
gas pressure ratio relative to optimal pressure ratio and lambda,
MAP_{eff} =
ƒ_{MAPeff}(MAP_{ratio},λ), where:
MAP_{eff} is intake manifold gas pressure
efficiency multiplier, dimensionless.
MAP_{ratio} is intake manifold gas pressure
ratio relative to optimal pressure ratio, dimensionless.
λ is intake manifold gas lambda, dimensionless.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intake manifold gas pressure ratio relative to optimal pressure ratio breakpoints, f_tqs_map_ratio_bpt
— Breakpoints
vector
Intake manifold gas pressure ratio relative to optimal pressure ratio breakpoints,
dimensionless.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intake manifold gas lambda breakpoints, f_tqs_lambda_bpt
— Breakpoints
vector
Intake manifold gas lambda breakpoints, dimensionless.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intake manifold gas temperature efficiency multiplier, f_tqs_mat_eff
— Intake temperature efficiency multiplier
array
The intake manifold gas temperature efficiency multiplier
lookup table, ƒ_{MATeff}, is a function of the engine
speed and intake manifold gas temperature relative to optimal temperature,
MAT_{eff} =
ƒ_{MATeff}(ΔMAT,N), where:
MAT_{eff} is intake manifold gas
temperature efficiency multiplier, dimensionless.
ΔMAT is intake manifold gas temperature relative to optimal
temperature, in K.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intake manifold gas temperature relative to optimal gas temperature breakpoints, f_tqs_mat_delta_bpt
— Breakpoints
vector
Intake manifold gas temperature relative to optimal gas temperature breakpoints,
in K.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intake manifold gas oxygen efficiency multiplier, f_tqs_o2pct_eff
— Intake oxygen efficiency multiplier
array
The intake manifold gas oxygen efficiency multiplier lookup
table, ƒ_{O2Peff}, is a function of the engine speed and
intake manifold gas oxygen percent relative to optimal, O2P_{eff} =
ƒ_{O2Peff}(ΔO2P,N), where:
O2P_{eff} is intake manifold gas oxygen
efficiency multiplier, dimensionless.
ΔO2P is intake gas oxygen percent relative to optimal, in
percent.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intake gas oxygen percent relative to optimal breakpoints, f_tqs_o2pct_delta_bpt
— Breakpoints
vector
Intake gas oxygen percent relative to optimal breakpoints, in percent.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Fuel rail pressure efficiency multiplier, f_tqs_fuelpress_eff
— Efficiency multiplier
array
The fuel rail pressure efficiency multiplier lookup table,
ƒ_{FUELPeff}, is a function of the engine speed
and fuel rail pressure relative to optimal breakpoints, FUELP_{eff}
= ƒ_{FUELPeff}(ΔFUELP,N), where:
FUELP_{eff} is fuel rail pressure
efficiency multiplier, dimensionless.
ΔFUELP is fuel rail pressure relative to optimal, in
MPa.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Fuel rail pressure relative to optimal breakpoints, f_tqs_fuelpress_delta_bpt
— Breakpoints
vector
Fuel rail pressure relative to optimal breakpoints, in MPa.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Fuel mass injection type identifier, f_tqs_f_inj_type
— Type identifier
vector
Fuel mass injection type identifier, dimensionless.
In the CI Core Engine and CI
Controller blocks, you can represent multiple injections with the start of injection
(SOI) and fuel mass inputs to the model. To specify the type of injection, use the
Fuel mass injection type identifier parameter.
Type of Injection  Parameter Value 

Pilot  0

Main  1

Post  2

Passed  3

The model considers Passed
fuel injections and fuel injected
later than a threshold to be unburned fuel. Use the Maximum start of injection angle
for burned fuel, f_tqs_f_burned_soi_limit parameter to specify the
threshold.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Indicated mean effective pressure post inject correction, f_tqs_imep_post_corr
— Post inject correction
array
The indicated mean effective pressure post inject correction
lookup table, ƒ_{IMEPpost}, is a function of the engine
speed and fuel rail pressure relative to optimal breakpoints,
ΔIMEP_{post} =
ƒ_{IMEPpost}(ΔSOI_{post},F_{post}), where:
ΔIMEP_{post} is indicated mean effective
pressure post inject correction, in Pa.
ΔSOI_{post} is indicated mean effective
pressure post inject start of inject timing centroid, in degATDC.
F_{post} is indicated mean effective
pressure post inject mass sum, in mg per injection.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Indicated mean effective pressure post inject mass sum breakpoints, f_tqs_f_post_sum_bpt
— Breakpoints
vector
Indicated mean effective pressure post inject mass sum breakpoints, in mg per
injection.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Indicated mean effective pressure post inject start of inject timing centroid breakpoints, f_tqs_soi_post_cent_bpt
— Breakpoints
vector
Indicated mean effective pressure post inject start of inject timing centroid
breakpoints, in degATDC.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Maximum start of injection angle for burned fuel, f_tqs_f_burned_soi_limit
— Maximum SOI angle for burned fuel
vector
Maximum start of injection angle for burned fuel, in degATDC.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Exhaust
Exhaust Temperature  Simple Torque Lookup
Exhaust temperature table, f_t_exh
— Lookup table
array
The lookup table for the
exhaust temperature is a function of injected fuel mass and engine
speed
where:
${T}_{exh}$ is
exhaust temperature, in K.
F is injected fuel mass, in mg
per injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Simple Torque Lookup
.
Fuel mass per injection breakpoints, f_t_exh_f_bpt
— Breakpoints
array
Engine load breakpoints used for exhaust temperature lookup table, in mg per
injection.
Dependencies
To enable this parameter, for Torque model, select
Simple Torque Lookup
.
Speed breakpoints, f_t_exh_n_bpt
— Breakpoints
array
Engine speed breakpoints used for exhaust temperature lookup table, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Simple Torque Lookup
.
Exhaust Temperature  Torque Structure
Optimal exhaust manifold gas temperature, f_tqs_exht
— Optimal exhaust manifold gas temperature
array
The optimal exhaust manifold gas temperature lookup table,
ƒ_{Texh}, is a function of the engine speed
engine speed and injected fuel mass, Texh_{opt} =
ƒ_{Texh}(F,N), where:
Texh_{opt} is optimal exhaust manifold gas
temperature, in K.
F is compression stroke injected fuel mass, in mg per
injection.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Main start of injection timing exhaust temperature efficiency multiplier, f_tqs_exht_mainsoi_eff
— Main SOI timing efficiency multiplier
array
The main start of injection (SOI) timing exhaust temperature
efficiency multiplier lookup table, ƒ_{SOIexhteff}, is a
function of the engine speed engine speed and injected fuel mass,
SOI_{exhteff} =
ƒ_{SOIexhteff}(ΔSOI,N), where:
SOI_{exhteff} is main SOI exhaust
temperature efficiency multiplier, dimensionless.
ΔSOI is main SOI timing relative to optimal timing, in
degBTDC.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intake manifold gas pressure exhaust temperature efficiency multiplier, f_tqs_exht_map_eff
— Intake manifold efficiency multiplier
array
The intake manifold gas pressure exhaust temperature efficiency
multiplier lookup table, ƒ_{MAPexheff}, is a function of
the intake manifold gas pressure ratio relative to optimal pressure ratio and lambda,
MAP_{exheff} =
ƒ_{MAPexheff}(MAP_{ratio},λ), where:
MAP_{exheff} is intake manifold gas
pressure exhaust temperature efficiency multiplier, dimensionless.
MAP_{ratio} is intake manifold gas pressure
ratio relative to optimal pressure ratio, dimensionless.
λ is intake manifold gas lambda, dimensionless.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intake manifold gas temperature exhaust temperature efficiency multiplier, f_tqs_exht_mat_eff
— Intake manifold efficiency multiplier
array
The intake manifold gas temperature exhaust temperature
efficiency multiplier lookup table, ƒ_{MATexheff}, is a
function of the engine speed and intake manifold gas temperature relative to optimal
temperature, MAT_{exheff} =
ƒ_{MATexheff}(ΔMAT,N), where:
MAT_{exheff} is intake manifold gas
temperature exhaust temperature efficiency multiplier, dimensionless.
ΔMAT is intake manifold gas temperature relative to optimal
temperature, in K.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Intake manifold gas oxygen exhaust temperature efficiency multiplier, f_tqs_exht_o2pct_eff
— Intake manifold efficiency multiplier
array
The intake manifold gas oxygen exhaust temperature efficiency
multiplier lookup table, ƒ_{O2Pexheff}, is a function of
the engine speed and intake manifold gas oxygen percent relative to optimal,
O2P_{exheff} =
ƒ_{O2Pexheff}(ΔO2P,N), where:
O2P_{exheff} is intake manifold gas oxygen
exhaust temperature efficiency multiplier, dimensionless.
ΔO2P is intake gas oxygen percent relative to optimal, in
percent.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Fuel rail pressure exhaust temperature efficiency multiplier, f_tqs_exht_fuelpress_eff
— Fuel rail pressure exhaust temperature efficiency multiplier
array
The fuel rail pressure efficiency exhaust temperature
multiplier lookup table, ƒ_{FUELPexheff}, is a function
of the engine speed and fuel rail pressure relative to optimal breakpoints,
FUELP_{exheff} =
ƒ_{FUELPexheff}(ΔFUELP,N), where:
FUELP_{exheff} is fuel rail pressure
exhaust temperature efficiency multiplier, dimensionless.
ΔFUELP is fuel rail pressure relative to optimal, in
MPa.
N is engine speed, in rpm.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Postinjection cylinder wall heat loss transfer coefficient, f_tqs_exht_post_inj_wall_htc
— Postinjection offset
scalar
Postinjection cylinder wall heat loss transfer coefficient, in W/K.
Dependencies
To enable this parameter, for Torque model, select
Torque Structure
.
Emissions
CO2 mass fraction table, f_CO2_frac
— Carbon dioxide (CO_{2}) emission lookup table
array
The CI Core Engine CO_{2} emission
mass fraction lookup table is a function of engine torque and engine
speed, CO2 Mass Fraction = ƒ(Speed, Torque),
where:
CO2 Mass Fraction is the CO_{2} emission
mass fraction, dimensionless.
Speed is engine speed, in rpm.
Torque is engine torque, in N·m.
Dependencies
To enable this parameter, on the Exhaust tab, select
CO2.
CO mass fraction table, f_CO_frac
— Carbon monoxide (CO) emission lookup table
array
The CI Core Engine CO emission
mass fraction lookup table is a function of engine torque and engine
speed, CO Mass Fraction = ƒ(Speed, Torque),
where:
CO Mass Fraction is the CO emission
mass fraction, dimensionless.
Speed is engine speed, in rpm.
Torque is engine torque, in N·m.
Dependencies
To enable this parameter, on the Exhaust tab, select
CO.
HC mass fraction table, f_HC_frac
— Hydrocarbon (HC) emission lookup table
array
The CI Core Engine HC emission
mass fraction lookup table is a function of engine torque and engine
speed, HC Mass Fraction = ƒ(Speed, Torque),
where:
HC Mass Fraction is the HC emission
mass fraction, dimensionless.
Speed is engine speed, in rpm.
Torque is engine torque, in N·m.
Dependencies
To enable this parameter, on the Exhaust tab, select
HC.
NOx mass fraction table, f_NOx_frac
— Nitric oxide and nitrogen dioxide (NOx) emission lookup table
array
The CI Core Engine NOx
emission mass fraction lookup table is a function of engine torque
and engine speed, NOx Mass Fraction = ƒ(Speed, Torque),
where:
NOx Mass Fraction is the NOx emission
mass fraction, dimensionless.
Speed is engine speed, in rpm.
Torque is engine torque, in N·m.
Dependencies
To enable this parameter, on the Exhaust tab, select
NOx.
PM mass fraction table, f_PM_frac
— Particulate matter (PM) emission lookup table
array
The CI Core Engine PM emission mass
fraction lookup table is a function of engine torque and engine speed where:
PM is the PM emission mass fraction,
dimensionless.
Speed is engine speed, in rpm.
Torque is engine torque, in N·m.
Dependencies
To enable this parameter, on the Exhaust tab, select
PM.
Engine speed breakpoints, f_exhfrac_n_bpt
— Breakpoints
vector
Engine speed breakpoints used for the emission mass fractions lookup tables, in
rpm.
Dependencies
To enable this parameter, on the Exhaust tab, select
CO2, CO, NOx,
HC, or PM.
Engine torque breakpoints, f_exhfrac_trq_bpt
— Breakpoints
vector
Engine torque breakpoints used for the emission mass fractions lookup tables, in
N·m.
Dependencies
To enable this parameter, on the Exhaust tab, select
CO2, CO, NOx,
HC, or PM.
Exhaust gas specific heat at constant pressure, cp_exh
— Specific heat
scalar
Exhaust gasspecific heat, $C{p}_{exh}$, in J/(kg·K).
Fuel
Stoichiometric airfuel ratio, afr_stoich
— Airfuel ratio
scalar
Fuel lower heating value, fuel_lhv
— Heating value
scalar
Fuel lower heating value, LHV, in J/kg.
Fuel specific gravity, fuel_sg
— Specific gravity
scalar
Specific gravity of fuel,
Sg_{fuel},
dimensionless.
References
[1] Heywood, John B. Internal Combustion Engine
Fundamentals. New York: McGrawHill, 1988.
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