CI Core Engine

Compression-ignition engine from intake to exhaust port

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Libraries:
Powertrain Blockset / Propulsion / Combustion Engine Components / Core Engine

Description

The CI Core Engine block implements a compression-ignition (CI) engine from intake to the exhaust port. You can use the block for hardware-in-the-loop (HIL) engine control design or vehicle-level fuel economy and performance simulations.

The CI Core Engine block calculates:

• Brake torque

• Exhaust temperature

• Air-fuel ratio (AFR)

• Fuel rail pressure

• Engine-out (EO) exhaust emissions:

  • Hydrocarbon (HC)

  • Carbon monoxide (CO)

  • Nitric oxide and nitrogen dioxide (NOx)

  • Carbon dioxide (CO₂)

  • Particulate matter (PM)

Air Mass Flow

To calculate the air mass flow, the compression-ignition (CI) engine uses the CI Engine Speed-Density Air Mass Flow Model. The speed-density model uses the speed-density 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 back-pressure Burned fuel mass Intake manifold gas pressure, temperature, and oxygen percentage Fuel rail pressure To account for the effect of post-inject 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.

${\dot{m}}_{fuel}=\frac{N\cdot N_{cyl}}{Cps\left(\frac{60s}{\min }\right)\left(\frac{1000mg}{g}\right)}{\displaystyle \sum m_{fuel,inj}}$

To calculate the fuel economy for high-fidelity models, the block uses the volumetric fuel flow.

$$Q_{fuel}=\frac{{\dot{m}}_{fuel}}{\left(\frac{1000kg}{m^3}\right)S{g}_{fuel}}$$

The equation uses these variables.

${\dot{m}}_{fuel}$	Fuel mass flow, g/s
mfuel,inj	Fuel mass per injection
$$Cps$$	Crankshaft revolutions per power stroke, rev/stroke
$N_{cyl}$	Number of engine cylinders
N	Engine speed, rpm
Qfuel	Volumetric fuel flow
Sgfuel	Specific gravity of fuel

The block uses the internal signal FlwDir to track the direction of the flow.

Air-Fuel Ratio

To calculate the air-fuel (AFR) ratio, the CI Core Engine and SI Core Engine blocks implement this equation.

$AFR=\frac{{\dot{m}}_{air}}{{\dot{m}}_{fuel}}$

The CI Core Engine uses this equation to calculate the relative AFR.

$\lambda =\frac{AFR}{AF{R}_s}$

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.

$$EG{R}_{pct}=100\frac{{\dot{m}}_{intk,b}}{{\dot{m}}_{intk}}=100y_{intk,b}$$

The equations use these variables.

$AFR$	Air-fuel ratio
AFRs	Stoichiometric air-fuel ratio
${\dot{m}}_{intk}$	Engine air mass flow
${\dot{m}}_{fuel}$	Fuel mass flow
λ	Relative AFR
yintk,b	Intake burned mass fraction
EGRpct	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.	$T_{exh}=f_{Texh}(F,N)$
Torque Structure	The nominal exhaust temperature, Texhnom, 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, Texhnom, is offset by a post temperature effect, ΔTpost, that accounts for post and late injections during the expansion and exhaust strokes.	$\begin{array}{l}{T}_{exhnom}=SO{I}_{exhteff}MA{P}_{exhteff}MA{T}_{exhteff}O2p_{exhteff}FUEL{P}_{exhteff}Tex{h}_{opt}\\ T_{exh}=T_{exhnom}+\Delta T_{post}\\ \\ SO{I}_{exhteff}=f_{SO{I}_{exhteff}}\left(\Delta SOI,N\right)\\ MA{P}_{exhteff}=f_{MA{P}_{exhteff}}\left(MA{P}_{ratio},\lambda \right)\\ MA{T}_{exhteff}=f_{MA{T}_{exhteff}}\left(\Delta MAT,N\right)\\ O2p_{exhteff}=f_{O2p_{exhteff}}\left(\Delta O2p,N\right)\\ Tex{h}_{opt}=f_{Texh}(F,N)\end{array}$

The equations use these variables.

F	Compression stroke injected fuel mass
N	Engine speed
Texh	Exhaust manifold gas temperature
Texhopt	Optimal exhaust manifold gas temperature
ΔTpost	Post injection temperature effect
Texhnom	Nominal exhaust temperature
SOIexhteff	Main SOI exhaust temperature efficiency multiplier
ΔSOI	Main SOI timing relative to optimal timing
MAPexheff	Intake manifold gas pressure exhaust temperature efficiency multiplier
MAPratio	Intake manifold gas pressure ratio relative to optimal pressure ratio
λ	Intake manifold gas lambda
MATexheff	Intake manifold gas temperature exhaust temperature efficiency multiplier
ΔMAT	Intake manifold gas temperature relative to optimal temperature
O2Pexheff	Intake manifold gas oxygen exhaust temperature efficiency multiplier
ΔO2P	Intake gas oxygen percent relative to optimal
FUELPexheff	Fuel rail pressure exhaust temperature efficiency multiplier
ΔFUELP	Fuel rail pressure relative to optimal

EO Exhaust Emissions

The block calculates these engine-out (EO) exhaust emissions:

• Hydrocarbon (HC)

• Carbon monoxide (CO)

• Nitric oxide and nitrogen dioxide (NOx)

• Carbon dioxide (CO₂)

• Particulate matter (PM)

The exhaust temperature determines the specific enthalpy.

$h_{exh}=C{p}_{exh}{T}_{exh}$

The exhaust mass flow rate is the sum of the intake port air mass flow and the fuel mass flow.

${\dot{m}}_{exh}={\dot{m}}_{intake}+{\dot{m}}_{fuel}$

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.

$$\begin{array}{l}{y}_{exh,i}=f_{i\_frac}(T_{brake},N)\\ {\dot{m}}_{exh,i}={\dot{m}}_{exh}{y}_{exh,i}\end{array}$$

The fraction of air and fuel entering the intake port, injected fuel, and stoichiometric AFR determine the air mass fraction that exits the exhaust.

$$y_{exh,air}=\max \left[y_{in,air}-\frac{{\dot{m}}_{fuel}+y_{in,fuel}{\dot{m}}_{intake}}{{\dot{m}}_{fuel}+{\dot{m}}_{intake}}AF{R}_s\right]$$

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.

$$y_{exh,b}=\max \left[(1-y_{exh,air}-y_{exh,HC}),0\right]$$

The equations use these variables.

$T_{exh}$	Engine exhaust temperature
$h_{exh}$	Exhaust manifold inlet-specific 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
yexh,i	Exhaust mass fraction for i = CO2, CO, HC, NOx, air, burned gas, and PM
$${\dot{m}}_{exh,i}$$	Exhaust mass flow rate for i = CO2, CO, HC, NOx, air, burned gas, and PM
Tbrake	Engine brake torque
N	Engine speed
yexh,air	Exhaust air mass fraction
yexh,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 Positive signals indicate flow into block Negative signals indicate flow out of block	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 Positive signals indicate an input Negative signals indicate a loss	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 Positive signals indicate an increase Negative signals indicate a decrease	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 Positive signals indicate flow into block Negative signals indicate flow out of block	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 Positive signals indicate an input Negative signals indicate a loss	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 Positive signals indicate an increase Negative signals indicate a decrease	Not used

hexh	Exhaust manifold inlet-specific enthalpy
hintk	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
Tbrake	Brake torque
Tpump	Engine pumping work offset to inner torque
Tfric	Engine friction torque
LHV	Fuel lower heating value

Examples

Build Conventional Vehicle Model

Build a vehicle with an internal combustion engine using the conventional vehicle reference application.

Calibrate, Validate, and Optimize CI Engine with Dynamometer Test Harness

Simulate a compression-ignition (CI) engine and controller under a dynamometer test harness using the CI engine dynamometer reference application.

Ports

Input

FuelMass — Fuel injector pulse-width

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

Engine speed, N, in rpm.

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

two-way 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

two-way 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

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 steady-state cam phase angles	$L$	N/A
Afr			Air-fuel ratio at engine exhaust port	$AFR$	N/A
FuelMassFlw			Fuel flow into engine	${\dot{m}}_{fuel}$	kg/s
FuelVolFlw			Volumetric fuel flow	Qfuel	m3/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	$${\displaystyle \underset{0}{\overset{(360)Cps}{\int }}EngSpd\frac{180}{30}d\theta }$$ where $$Cps$$ is crankshaft revolutions per power stroke	degrees crank angle
EgrPct			EGR percent	EGRpct	N/A
EoAir			EO air mass flow rate	$${\dot{m}}_{exh}$$	kg/s
EoBrndGas			EO burned gas mass flow rate	yexh,b	kg/s
EoHC			EO hydrocarbon emission mass flow rate	yexh,HC	kg/s
EoCO			EO carbon monoxide emission mass flow rate	yexh,CO	kg/s
EoNOx			EO nitric oxide and nitrogen dioxide emissions mass flow rate	yexh,NOx	kg/s
EoCO2			EO carbon dioxide emission mass flow rate	yexh,CO2	kg/s
EoPm			EO particulate matter emission mass flow rate	yexh,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

two-way 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

two-way 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

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 back-pressure Burned fuel mass Intake manifold gas pressure, temperature, and oxygen percentage Fuel rail pressure To account for the effect of post-inject 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

4 (default) | scalar

Number of engine cylinders, $N_{cyl}$.

Air standard temperature, Pstd — Temperature

293.15 (default) | scalar

Standard air temperature, T_std, in K.

Crank revolutions per power stroke, Cps — Revolutions per stroke

2 (default) | scalar

Crankshaft revolutions per power stroke, $$Cps$$, in rev/stroke.

Total displaced volume, Vd — Volume

0.0015 (default) | scalar

Displaced volume, $V_d$, in m^3.

Ideal gas constant air, Rair — Constant

287.05 (default) | scalar

Ideal gas constant, $R_{air}$, in J/(kg·K).

Air standard pressure, Pstd — Pressure

101325 (default) | scalar

Standard air pressure, $P_{std}$, in Pa.

Speed-density 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

${\eta }_v=f_{{\eta }_v}(MAP,N)$

where:

• ${\eta }_v$ is engine volumetric efficiency, dimensionless.

• MAP is intake manifold absolute pressure, in KPa.

• N is engine speed, in rpm.

Speed-density intake manifold pressure breakpoints, f_nv_prs_bpt — Breakpoints

vector

Intake manifold pressure breakpoints for speed-density volumetric efficiency lookup table, in KPa.

Speed-density engine speed breakpoints, f_nv_n_bpt — Breakpoints

vector

Engine speed breakpoints for speed-density 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

[0 3.5714 7.1429 10.7143 14.2857 17.8571 21.4286 25 28.5714 32.1429 35.7143 39.2857 42.8571 46.4286 50] (default) | 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

[1000 1410.7143 1821.4286 2232.1429 2642.8571 3053.5714 3464.2857 3875 4285.7143 4696.4286 5107.1429 5517.8571 5928.5714 6339.2857 6750] (default) | 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

[500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 4000] (default) | 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

[0.8;0.85;0.9;0.95;1;1.05;1.1;1.15;1.2;1.25;1.3;1.35;1.4;1.45;1.5] (default) | 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

[1.5 1.678571428571429 1.857142857142857 2.035714285714286 2.214285714285714 2.392857142857143 2.571428571428571 2.75 2.928571428571429 3.107142857142857 3.285714285714286 3.464285714285714 3.642857142857143 3.821428571428572 4] (default) | 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

[-55;-50;-45;-40;-35;-30;-25;-20;-15;-10;-5;0;5;10;15] (default) | 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

0 (default) | scalar

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

[0 3.571428571428572 7.142857142857143 10.71428571428571 14.28571428571429 17.85714285714286 21.42857142857143 25 28.57142857142857 32.14285714285715 35.71428571428572 39.28571428571428 42.85714285714285 46.42857142857143 50] (default) | 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

[150 160.7142857142857 171.4285714285714 182.1428571428571 192.8571428571429 203.5714285714286 214.2857142857143 225 235.7142857142857 246.4285714285714 257.1428571428571 267.8571428571429 278.5714285714286 289.2857142857143 300] (default) | 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

500 (default) | scalar

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

$T_{exh}=f_{Texh}(F,N)$

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

[0 3.5714 7.1429 10.7143 14.2857 17.8571 21.4286 25 28.5714 32.1429 35.7143 39.2857 42.8571 46.4286 50] (default) | 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

[1000 1410.7143 1821.4286 2232.1429 2642.8571 3053.5714 3464.2857 3875 4285.7143 4696.4286 5107.1429 5517.8571 5928.5714 6339.2857 6750] (default) | 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.

Post-injection cylinder wall heat loss transfer coefficient, f_tqs_exht_post_inj_wall_htc — Post-injection offset

0 (default) | scalar

Post-injection 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 (CO₂) emission lookup table

array

The CI Core Engine CO₂ 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 CO₂ 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

[750 1053.57142857143 1357.14285714286 1660.71428571429 1964.28571428571 2267.85714285714 2571.42857142857 2875 3178.57142857143 3482.14285714286 3785.71428571429 4089.28571428571 4392.85714285714 4696.42857142857 5000] (default) | 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

[0 15 26.4285714285714 37.8571428571429 49.2857142857143 60.7142857142857 72.1428571428571 83.5714285714286 95 106.428571428571 117.857142857143 129.285714285714 140.714285714286 152.142857142857 163.571428571429 175] (default) | 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

1005 (default) | scalar

Exhaust gas-specific heat, $C{p}_{exh}$, in J/(kg·K).

Fuel

Stoichiometric air-fuel ratio, afr_stoich — Air-fuel ratio

14.6 (default) | scalar

Air-fuel ratio, $AFR$.

Fuel lower heating value, fuel_lhv — Heating value

42e6 (default) | scalar

Fuel lower heating value, LHV, in J/kg.

Fuel specific gravity, fuel_sg — Specific gravity

0.832 (default) | scalar

Specific gravity of fuel, Sg_fuel, dimensionless.

References

[1] Heywood, John B. Internal Combustion Engine Fundamentals. New York: McGraw-Hill, 1988.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2017a