GT Aftertreatment Modeling Tool for Interface Simulations11/09/2015

Bhargav Ranganath

Outline

Objective

Target customer

Key players and uncertainties

Tool requirements

Project outline

Results

Summary

Objective

Investigate GT aftertreatment tool for carrying out whole AT

configuration level interface simulation using custom kinetics

– Aftertreatment configuration: Pipe-DOC-DPF-Pipe-Doser-Pipe-SCR-

AMOX

– Simulink as integration tool: Run Aftertreatment plant model in GT

interfaced with Simulink.

Target Customers

System Pure Simulation

Controls Development and Calibration

Simulink

AT Simulation tool

AT Simulation

tool

Real-time Application

Aftertreatment Pure Simulation

Temperature Prediction

Emission Prediction

AT Simulation

tool

Key Players and Uncertainties

Key players

– CMI: Model development and controls teams

– Gamma Technology Aftertreatment and interface teams

– JMI model development team

Key uncertainties

– Tool transparency to custom models

– Tool features available to model given technology

– Modular kinetics

– Resource availability to model at supplier end

Tool Requirements

Requirements

Ability to model basic aftertreatment

components – Pipe, DOC, SCR, DPF and

AMOX

Real time or faster in both native and

interface modes

Implement custom chemistry and transport Stability under high transient conditions

Include features to model multiple sites and

zones

Ability to actuate robustly all BC from

interface tools

Encrypted kinetics models Ability to model flow bypass

Handle transitions to and from zero flow Smooth integration with interface tools

Correct representation of heat transfer in all

components

Clearer help documents and discernable

error messages

Ability to model complex aftertreatment

components – TWC, SCRF, LNT

Include features to model multiple layers

Project Outline

CMI developed SCR and AMOX kinetics

JMI provided DOC model

GT default DPF models

Interface Application: AT configuration in GT interfaced with Simulink

Engine data: Configuration model accuracy – qualitative and quantitative validation

Speed and stability in native application

Native Application: AT Configuration in GT (catalysts and pipes)

Reactor data – Component model accuracy qualitative/quantitative validation

Ease of custom kinetic model implementation within GT

Same accuracy as GT native simulation

Speed and stability same as native application

Project Outline

CMI developed SCR and AMOX kinetics

JMI provided DOC model

GT default DPF models

Interface Application: AT configuration in GT interfaced with Simulink

Engine data: Configuration model accuracy – qualitative and quantitative validation

Speed and stability in native application

Native Application: AT Configuration in GT (catalysts and pipes)

Reactor data – Component model accuracy qualitative/quantitative validation

Ease of custom kinetic model implementation within GT

Same accuracy as GT native simulation

Speed and stability same as native application

CMI SCR Model

Model kinetics transferred from current simulation tool

Multiple site model with multiple surface site species

Developed kinetics modular and does not include transport terms

No washcoat pore diffusion included

NO

xO

nly NOx + NH3

NH3 Only

NOx Only

Reactor Data Validation: Boundary Conditions and Parameters

4 step protocol

SV: 120 [k/hour]

Zero initial NH3 storage

ANR~1 under step 2

– Standard SCR

– Fast SCR

Four Step Protocol

Reactor data validation – NOx conversion from step 2

Model predictions off at extreme end temperatures

– NH3 oxidation at high temperature and NH4NO3 formation at lower

temperature in presence of NO2

Nox split: 0 Nox split: 0.5

0

20

40

60

80

100

120

0 200 400 600 800

NO

x C

on

v [%

]

Temperature [DegC]

Step 2 NOx Conversion

Test GT

0

20

40

60

80

100

120

0 200 400 600 800

NO

x C

on

v [%

]

Temperature [DegC]

Step 2 NOx Conversion

Test GT

NH4NO3

formation and

decomposition

NH3

oxidation

NH3

oxidation

Summary – CMI SCR model

In house developed SCR kinetics implemented in GT

Multiple site model with multiple surface site species implemented

Model captures the correct functionality of the technology

Caution to prevent compensating for deficiencies in kinetics through

mass transport

CMI AMOX Model

Two layer AMOX kinetics implemented – SCR kinetics and PGM

kinetics

Includes pore diffusion

– Effective diffusive resistance at 200 [DegC] specified for species

SV: 160 [k/hour]

Step 2: ANR=1.0; Step 3: NH3 only

AMOX: ANR=1; NO only NOx

Overall the model captures the correct

trends compared to data

– NH3 conversion, NOx conversion/make and

N2O make

NOx conversion and NOx slip at higher

temperatures

– GT predictions good under step 3 and off

under step 2

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600

NH

3 C

on

vers

ion

[%

], N

Ox

and

N2

O m

ake

[pp

m]

Temperature [ Deg C]

Step -3

Test - NH3 Conversion

Sim - NH3 Conversion

Test - NOx make

Sim - NOx make

Test - N2O make

Sim - N2O make

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600

NO

x an

d N

H3

Co

nve

rsio

n [

%]

and

N2

O m

ake

[pp

m]

Temperature [DegC]

Step - 2

Test - NOx Conversion

Sim - Nox Conversion

Test - NH3 Conversion

Sim - NH3 Conversion

Test - N2O make

Sim - N2O make

Summary – CMI AMOX model

In-house two layer AMOX model implemented in GT

– Pore diffusion introduced for transport of species within the two layers

– Constant diffusive resistances at 200 [DegC] temperature

Model predictions good under low temperatures and reasonable under

high temperature

Model captures the correct trends and functionalities of the technology

Caution to prevent compensating for deficiencies in kinetics through

mass transport

JM DOC

DOC kinetics model developed with in-house tool and implemented in

GT

Both internal and external mass transfer implemented

Model from JMI shared with CMI as a compound object with access to

variables and parameters through compound interface

Supplier provided validation – Engine data: NO an HC Oxidation

Courtesy JMI

NO Oxidation

SV: 45-140 [k/hour]

Inlet Feed: THC, NOx

and CO

HC Oxidation

SV: 50-180 [k/hour]

Inlet Feed: THC, NOx

and CO

Project Outline

CMI developed SCR and AMOX kinetics

JMI provided DOC model

GT default DPF models

Interface Application: AT configuration in GT interfaced with Simulink

Engine data: Configuration model accuracy – qualitative and quantitative validation

Speed and stability in native application

Native Application: AT Configuration in GT (catalysts and pipes)

Reactor data – Component model accuracy qualitative/quantitative validation

Ease of custom kinetic model implementation within GT

Same accuracy as GT native simulation

Speed and stability same as native application

AT Configuration Model Setup

DOC DPF SCRPipe2 Pipe3 SCR AMOXEnd PipeExhaust

Comp

300

350

400

450

500

550

600

650

700

0

0.05

0.1

0.15

0.2

0.25

0.3

0 1000 2000 3000 4000

IT [

K]

IMf

[kg

/s]

Time [s]

Boundary Conditions

Inlet Mass Flow Rate

Inlet Temperature

0.00E+00

2.00E-04

4.00E-04

6.00E-04

8.00E-04

1.00E-03

1.20E-03

1.40E-03

0 1000 2000 3000 4000

NO

, NO

2 [

mo

le f

ract

ion

]

Time [s]

Inlet NO and NO2

Inlet NO

Inlet NO2

Cold Soak Warm

Inle

t M

ass F

low

[kg/s

]

Inle

t Tem

pera

ture

[K

]

Configuration Model Development and Results

Simulation carried out in GT version 7.5 build 2

Configuration built with JMI DOC, CMI SCR and AMOX and GT DPF

models

Both variable diameter and bends implemented in pipe geometry

Non-adiabatic boundary conditions implemented for all components

No additional calibration work for GT – all parameters from test

Model time step set to input data frequency

No soot in boundary condition

Cold FTP – GT/Test comparison

0

100

200

300

400

500

600

700

0 200 400 600 800 1000 1200 1400

Tem

per

atu

re [

Deg

C]

Time [s]

DOC Inlet Gas Temperature

DOC IT - Test

DOC_IT - GT

0

100

200

300

400

500

600

700

0 500 1000 1500

Tem

per

atu

re [

Deg

C]

Time [s]

DOC Outlet Gas Temperature

DOC_OT - Test

DOC_OT - GT

0

100

200

300

400

500

600

700

0 500 1000 1500

Tem

per

atu

re [

Deg

C]

Time [s]

DPF Outlet Gas Temperature

DPF_OT - Test

DPF_OT - GT

0

100

200

300

400

500

600

700

0 500 1000 1500

Tem

per

atu

re [

Deg

C]

Time [s]

SCR1 Outlet Gas Temperature

SCR1_OT - Test

SCR1_OT - GT

No heat addition/removal due to

water condensation and

evaporation modeled [1]

Tem

pera

ture

[K

]

Tem

pera

ture

[K

]Tem

pera

ture

[K

]

Tem

pera

ture

[K

]

Cold FTP – GT/Test comparison

Temperature from Simulation

higher compared to test

Higher temperature results in better

NOx conversion from simulation

2D effects not captured in model

can render better conversion from

simulation

Overall trend matches with data0.00

10.00

20.00

30.00

40.00

50.00

0 500 1000 1500

NO

x [g

]

Time [s]

Cold Cycle Cumulative Out NOx

GT Inlet NOx

GT Outlet NOx

Test Outlet NOx

GT Native Simulation Speed Summary

GT simulation speed fast compared to Real time

Configuration Boundary condition Real

Time [s]

Simulation time to real

time for GT native

DOC-DPF-SCR-SCR-AMOX Cold FTP 1200 0.188

DPF-SCR-SCR-AMOX Cold FTP-soak-Warm FTP 3613 0.22

DOC-DPF-SCR-SCR-AMOX Cold FTP-Soak-Warm FTP 36130.24

SCR 3xRMCSet 7290 0.049

DOC-DPF-SCR Idle-C100 18000 0.28

DOC-DPF-SCR-SCR-AMOX Highly transient BC with

soak

34071.029

Project Outline

CMI developed SCR and AMOX kinetics

JMI provided DOC model

GT default DPF models

Interface Application: AT configuration in GT interfaced with Simulink

Engine data: Configuration model accuracy – qualitative and quantitative validation

Speed and stability in native application

Native Application: AT Configuration in GT (catalysts and pipes)

Reactor data – Component model accuracy qualitative/quantitative validation

Ease of custom kinetic model implementation within GT

Same accuracy as GT native simulation

Speed and stability same as native application

GT/Simulink Setup

Mode

– Run GT as .gtm

– Run GT as .dat

– Compile and run GT as .dat from Simulink

Actuate BC from Simulink using scripts

Update model parameters from Simulink using scripts

Same license used between GT native and GT/Simulink application

Post processing GT results possible from Simulink or GT-Post Actuate parameters

from Simulink

Actuate BC

from Simulink

GT Simulink

Object

GT AT config model

GT simulation – Native GT and GT-Simulink

Configuration: DeCompPipe-CMI_SCR

Boundary conditions: 3 back to back RMCSet

cycle

SV: 6-60 [k/hour]

CMI SCR kinetics

100

200

300

400

500

0

0.05

0.1

0.15

0.2

0.25

0.3

0 2000 4000 6000 8000

Tem

pe

ratu

re [

Deg

C]

Exh

Mas

s Fl

ow

Rat

e [k

g/s

]

Time [s]

RMCSet BC

Exh Mf

Exh Temp

GT simulation – Native GT and GT-Simulink

0.00

50.00

100.00

150.00

0 2000 4000 6000 8000

NO

[p

pm

]

Time [s]

Outlet NO

GT_GT

Simulink_GT

0.00

50.00

100.00

150.00

0 2000 4000 6000 8000

NO

2 [

pp

m]

Time [s]

Outlet NO2

GT_GT

Simulink_GT

0.00

100.00

200.00

300.00

400.00

500.00

0 2000 4000 6000 8000

NH

3 [

pp

m]

Time [s]

Outlet NH3

GT_GT

Simulink_GT

No difference between GT native

and GT/Simulink results

GT in Simulink Simulation Speed Summary

GT robust handling actuation of all BC from Simulink while running multi-component configuration with challenging boundary conditions

GT takes similar times both in native and from Simulink mode

Configuration Boundary

condition

Real

Time

[s]

Simulation

time to real

time for GT

native

Simulation

time to Real

time for

GT/Simulink

DOC-DPF-SCR-SCR-

AMOX

Cold FTP-Soak-

Warm FTP

3613 0.24 0.26

SCR 3xRMCSet 7290 0.049 0.054

DOC-DPF-SCR Idle-C100 18000 0.28 0.267

DOC-DPF-SCR-SCR-

AMOX

Highly transient

BC with soak

3407 1.02 0.85

Tool Requirements

Requirements

Ability to model basic aftertreatment

components – Pipe, DOC, SCR, DPF and

AMOX

Real time or faster in both native and

interface modes

Implement custom chemistry and transport Stability under high transient conditions

Include features to model multiple sites Ability to actuate robustly all BC from

interface tools

Encrypted kinetics models Ability to model flow bypass

Handle transitions to and from zero flow Smooth integration with interface tools

Correct representation of heat transfer in all

components

Clearer help documents and discernable

error messages

Ability to model complex aftertreatment

components – TWC, SCRF, LNT

Include features to model multiple layers

and zones

Summary

Custom component models implemented and validated from GT

Configuration model built in GT and validated in native application

GT simulation fast and robust in handling highly transient BC in both

native and Simulink application

GT Simulation results same from both native and Simulink application

Follow up with further evaluation of the tool

Acknowledgements

GT support team

Rohan Gumaste for GT support within CMI

SPA AT team from Cummins

CTI team from Cummins

Reference

1. SAE Int. J. Commer. Veh. 2013-01-1064, Cold Start Effect

Phenomena over Zeolite SCR Catalysts for Exhaust Gas

Aftertreatment