real time gt-power simulation for emission prediction … · real time gt-power simulation for...

Real Time GT-POWER Simulation for Emission Prediction for Engine Verification

Elias Johansson, Volvo GTT Gothenburg

Volvo GTT, GOT Elias Johansson, System Analysis & Simulations

2012-11-05

Request: More robust engine emission verification Tool: ”Virtual Test Rig” for Transient Cycle Emission Simulations using Engine/EATS/vEMS-model with live SiL control


2012-11-05

Presentation Agenda

System overview and description

Model development process

Correlation of model to real system behaviour

Cycle simulation results

Delivery for certification process of Volvo EuVI engine

Questions


2012-11-05

Simulation System Overview

Application and live monitoring

of EMS in ATI Vision Operating control in engineSIL

vEMS (compiled EMS) + DST vEMS software + DST

Simulation strategy

GT-Power RT Engine model

Volvo EATS model


2012-11-05

Simulation System Overview

GT-Power RT Engine model

Volvo EATS model vEMS (compiled EMS) + DST vEMS software + DST

Simulation strategy


2012-11-05

Simulation System Overview Operating control in engineSIL

vEMS

Engine model

EATS model (DOC+DPF+SCR

with urea buffer)

Actuators

Sensors

Control

Demand

Actuators

Sensors

Drive cycle and Environment

Road cycle/Engine test


2012-11-05


vEMS

Engine model


with urea buffer)

Actuators

Sensors

Control

Demand

Actuators

Sensors


Matlab

Logging signals



2012-11-05


vEMS

Engine model


with urea buffer)

Actuators

Sensors

Control

Demand

Actuators

Sensors


Matlab

Compare to test data

Calculate Fuel Consumption,

WBW NOx etc.


Matlab

Logging signals


2012-11-05

Processing of Simulation and Results

Matlab script for:

Running pre-specified simulations

Storing/writing of sampled data (to Excel)

Easy plotting/comparison of results

Calculating WBW-NOx and other parameters

Matlab

System requirements for finished coupled and evaluated model

PC with one Matlab/Simulink license

Simulation speed on 2.4GHz PC ~ 4 times faster than RT


2012-11-05

Model Development Process

Detailed engine model calibrated

to HW engine in 35 SS points

DOE of 8000 experiments

with 8 input parameters

Transient calibration

of MV (RT) model

Wall Temp Solver, Turbo inertia

Filtering NN outputs

Actuator delays

RT model coupled to vEMS

and EATS models in Simulink

∆T=

100°C

70s 300s

System evaluation in

Vision

Mode coordinators

Nox sensors

Urea dosing/buffering


2012-11-05

Engine Model

MV cylinder with neural networks trained from detailed model with

injection, combustion and NOx model. Cylinder trained within large

ranges of dependent parameters.

Eng rpm, Boost T, Boost P, Exh P, Fuel mass, SOI, Fuel P, EGR-fraction

predictive in wide range of engine running conditions

Physical properties retained from detailed GT-Power model (flow and

temperatures solved through the whole system). Turbo and EGR

circuit outside of MV-dependency

Faster than RealTime (~4times)

Physical interpretation of transients through thermal masses (transient

wall temp solver) in intake and exhaust system


2012-11-05

Engine Model

Turbo and EGR circuit modeled externally - same MV cylinder can

be combined with different Boosting and EGR systems


2012-11-05

Engine Model – Calibration process

Detailed model

Calibrated to Steady State test data for EuVI engine

MV-model

Refined calibration to test data (pulsating flow steady flow)

Dynamic ”lag” calibration of NN engine parameters and actuators

”Fast” temp sensor measurment for calibration of engine ExhMan temp

Transient calibration to measured cycle data and on-road PEMS

- Thermal mass, inertias, sensor slowliness

(Crucial for good prediction of SCR NOx conversion )


2012-11-05

Calibration Results of EuVI MV model


2012-11-05

Calibration Results of Eu6 MV model


2012-11-05

Closed Loop Model Interaction


2012-11-05

Closed Loop Model Interaction

T T T NOx NOx 𝒎 Urea

T exh

𝐦 exh

dP

EO Nox

EO O2frac

𝒎 HC

Engine

sensors

Engine

Actuators

vEMS

SOI

Inj P

Mfuel

EGR Valve

Exh Valve

ITV

WG

Pboost

Tboost

Texh

Pexh

Eng rpm

Eng Torque

Turbo rpm


2012-11-05

Model Transient Calibration

Correlation of ” real gas temperature” in exhaust through comparison

to transient cycle measured with fast Temp sensor


2012-11-05

Thermal mass

tuned

Without

Thermal mass

measured simulated

Model Transient Calibration


2012-11-05

Correlation of ” real gas temperature” in exhaust through

comparison to WHTC cycle with fast Temp sensor

Validation of temperature sensors and SCR functionality

through comparison to long road cycle with Urea and NOx

measurement

Model Transient Validation


2012-11-05

Model Transient Validation (ExhTemps and NOx conv.) Exhaust Temp

sensor value

SCR Temp

sensor value

NOx Eng out

NOx Syst out

Urea inj mf

DPF Temp

sensor value

measured simulated


2012-11-05


Steady State correlation (to measured data)

Within 2% of flow, temperatures and pressures

Transient correlation (to measured data)

1.1% BSFC over ISC (4h road) cycle

4.2% Engine out NOx over ISC cycle

8.1% System out NOx over ISC cycle

2.9% Urea consumption over ISC cycle

<30% SO NOx over WHTC, WHSC and WNTE cycles (incl low temp/high alt.

conditions )


2012-11-05

Correlation of ” real gas temperature” in exhaust through

comparison to transinet cycle with fast Temp sensor

Validation of temperature sensors and SCR functionality

through comparison to long road cycle with Urea dosing

and NOx measurment



2012-11-05

Drive Cycle

Environment ( Ambient Pressure, Temperature)

Software / Dataset

We can now run predictive simulations of any:

Transient behaviour of temperatures in exhaust system are correlated with

respect to thermal mass

NOx conversion is validated from different cycles and running conditions



2012-11-05

Useful Areas

Evaluation of new software and control strategies, heat modes etc

Early calibration work, extended EMS engine model etc.

Prediction of fuel (and urea) consumption and NOx emissions

Cycle simulations at warm/cold temperatures and high altitude

Robustness study on sensor/actuator variance (system level)

Regeneration strategies, ageing/poisoning of EATS


2012-11-05

Database Simulation for EuVI Certification


2012-11-05

Euro VI Emission Requirements

World Harmonised Steady State & Transient Cycles

(WHSC & WHTC)

Off-cycle emissions (OCE)

- World Harmonised Not-to-Exceed (WNTE) test

In Service Conformity (ISC)

- 4h road cycle incl. 15min stop

- Max WBW NOx requirement

All Certification cycles in test rig and on road was complemented

with simulated cycles at high altitude + warm and cold temperatures

In total ~200 cycles for 1 EuroVI engine concept were simulated


2012-11-05

The End

Thank You for Your kind attention!

Questions?

real time gt-power simulation for emission prediction … · real time gt-power simulation for...

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