CRANK-ANGLE RESOLVED REAL-TIME ENGINE MODELLING … · FOR HIL BASED VIRTUAL CALIBRATION Frankfurt, ... HP/LP EGR Reduced discretization level Same cylinder and turbocharger modelling

© by FEV – all rights reserved. Confidential – no passing on to third parties

Prepared for

European GT Conference 2018

Feihong Xia

CRANK-ANGLE RESOLVED REAL-TIME ENGINE MODELLING

FOR HIL BASED VIRTUAL CALIBRATION

Frankfurt, 08.10.2018

© by FEV – all rights reserved. Confidential – no passing on to third parties |

New challenges:

Short development cycle

High powertrain complexity

Real driving emissions

Benefit of HiL:

Early system calibration and

testing

Reduce cost of prototype

vehicles

Easy adaptation of testing

boundary conditions

Safe testing environment

Introduction & Motivation

European GT Conference 2018, Xia 2

MODEL BASED POWERTRAIN DEVELOPMENT PROCESS

System

Level

Module

Level

Component

Level

MiL

SiL

HiL

Front-loading


System

Level

Module

Level

Component

Level

Requirement of engine virtual

calibration

Closed-loop interaction between

engine model and ECU

Extent and accuracy of the

engine model

Real-time application



VIRTUAL CALIBRATION OF ECU

RT Engine Model for

HiL Testing

MiL

SiL

HiL

Front-loading


System

Level

Module

Level

Component

Level

Reutilization of 1D CFD

simulation models for concept

layout

Model transfer using the same

tool chain

Model reduction for real-time

application



MODEL TRANSFER FROM CONCEPT-STUDY TO SYSTEM CALIBRATION

MiL

SiL

HiL

1D CFD

Concept Layout

0D Model

HiL Testing

Real Time Factor

Model Complexity

100

10

1

0.1

0D Reduced

1D Detailed

Front-loading


Modelling Methodology


FROM 1D DETAILED MODEL TO 0D REDUCED MODEL

Xia, F., Lee, S., Andert, J., Kampmeier, A. et al., "Crank-Angle Resolved Real-Time Engine Modelling A Seamless Transfer from Concept Design to HiL Testing,"

SAE Technical Paper 2018-01-1245, 2018, https://doi.org/10.4271/2018-01-1245.

Model Reduction &

Run Time

Optimization

Example using a diesel engine model

2 l, 4 cylinder, single-stage turbocharger, HP/LP EGR

Reduced discretization level

Same cylinder and turbocharger modelling

0.1

1

10

100

1000

10000

DetailedTime step after Courant

ReducedFixed time step (0.334 ms) for

HiL

Number of flowcomponents / -

Number of timesteps (1 cycle @4000 1/min) / -

Real-time factor / -


Modelling Methodology


FROM 1D DETAILED MODEL TO 0D REDUCED MODEL



pcyl, test

pcyl, sim

Int. valve

pintake, sim

Exh. valve

pexhaust, sim

De

taile

dR

ed

uce

d

Low-end torque (1750 1/min, BMEP 25 bar)

Crank angle / ° CA

-180 -90 0 90 180 270 360 450 540

Pre

ssu

re / b

ar

1

2

3

4

5

Pre

ssu

re / b

ar

1

2

3

4

5

Va

lve

lift / m

m

0

2

4

6

8

Va

lve

lift / m

m

0

2

4

6

8

Model Reduction &

Run Time

Optimization


Reference engine

2 l, 4 cylinder diesel engine

Single-stage turbocharger

HP/LP EGR

Predictive combustion model

Explicit flow solver

Time step = 0.334 ms

(9 ° CA @ 4500 1/min)

Engine Model Validation


ENGINE MODEL INTRODUCTION



Turbine map

Compressor map

Flow coefficients

Combustion

Heat transfer

Volume

Heat transfer

Pressure

loss

Volume

Heat transfer

αThrottle

ϕRack

Injection

αEGR

αEGR

Measurement Calibration parameter Model inputs


With physical and empirical correlations for entrainment, evaporation, ignition, premixed combustion and diffusion



CALIBRATION OF THE PREDICTIVE COMBUSTION MODEL

“DIRECT-INJECTION DIESEL MULTI-PULSE MODEL“

GT-Power



Entrainment rate

multiplier

= 1.85 − 0.0005

∗𝑝rail𝑏𝑎𝑟

Ignition delay

multiplier2.1

Premixed combustion

rate multiplier0.46

Diffusion combustion

rate multiplier0.62

Engine Test Bench Cylinder Pressure Indication Combustion Model Parameters

En

gin

e b

rake

to

rqu

e

Engine speed

4

3

4

3

Selecteddata points

Number ofinjections

Measureddata points

TotalEGR rate




CALIBRATION OF THE PREDICTIVE COMBUSTION MODEL



modelling accuracyCylinder pressure

Inje

ctio

n r

ate

/ m

g/°

CA

0.000

0.025

0.050

0.075

0.100

No

rma

lize

db

urn

ra

te / %

0.0

2.5

5.0

7.5

10.0

Pre

ssu

re / b

ar

0

25

50

75

100

Crank angle / ° C

-90 -60 -30 0 30 60 90

Inj. rate

Simulated

Measured

Predicted

Engine speed / 1/min

IMEP / bar

0 5 10 15 20 25 30

Err

or IM

EP / -

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

5000 4000 3000 2000 1000 0

Err

or B

R / -

-0.05

-0.04

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

0.04

0.055000 4000 3000 2000 1000 0

Error IMEP

ErrorBR




STEADY STATE VALIDATION OF CYLINDER, AIR PATH AND TC MODELLING



TC speedEngine mapping

Rel. deviation ISFC[( sim - test ) / test] / %

Rel. deviation air mass flow[( sim - test ) / test] / %

Deviation temperatureupstr. turbine [sim-test] / ° C

Deviation max. cylinder pressure [sim-test] / bar

Fu

el m

ass / m

g/s

tro

ke

Fu

el m

ass / m

g/s

tro

ke

Engine speed / 1/min Engine speed / 1/min

1086420-2-4-6-8-10

543210-1-2-3-4-5

1086420-2-4-6-8-10

50403020100-10-20-30-40-50

0

50

100

150

200

250

0 50 100 150 200 250Turb

och

arge

r sp

eed

, sim

ula

ted

/ 1

00

0/m

in

Turbocharger speed, measured / 1000/min


Integration into ECU HiL Test Bench


Lee, S., Andert, J., Neumann, D., Querel, C. et al., "Hardware-in-the-Loop Based Virtual Calibration Approach to Meet Real Driving Emissions Requirements,"

SAE Technical Paper 2018-01-0869, 2018

p22, T22T21 THP-EGR

T3, λT4, ΔpDPF

TLP-EGR

ΔpLP-EGR

Tamb

pamb

LP-EGR

valve

HP-EGR

valveVGT

𝑚𝑎𝑖𝑟 ,T1

Injection

Contr

ol

signal

fro

m E

CUEngine

throttle

Sen

sor

signal

to E

CU


ECU connected as real

hardware

Artificial real vehicle

environment incl. CAN

communication for ECU

Co-simulation approach

Integration into ECU HiL Test Bench


SYSTEM OVERVIEW OF HIL IMPLEMENTATION

Lee, S., Andert, J., Neumann, D., Querel, C. et al., "Hardware-in-the-Loop Based Virtual Calibration Approach to Meet Real Driving Emissions Requirements,"

SAE Technical Paper 2018-01-0869, 2018

CCP

Mid-Size HiL

Simulator

Host PCWorkstation

with RTOS

ECU ECU & Bus

Interface Module

Ethernet

UDP

dSPACE

Link

Actuators + Loads

Electrical

interface

Electrical

interface


Closed-loop Interaction with Hardware ECU


ENGINE MAPPING IN CLOSED-LOOP WITH ECU



Actuator positionEngine operation points

0

10

20

30

40

50

60

70

80

90

100

0 25 50 75 100

Nor

mal

ized

mas

s flo

w ,

HiL

/ %

Normalized mass flow, engine test bench / %

Ref.

Air

Fuel

0

10

20

30

40

50

60

70

80

90

100

0 25 50 75 100A

ctua

tor

posi

tion,

HiL

/ %

Actuator position, engine test bench / %

Ref.

LP EGR valve

HP EGR valve

Turbine rack position


Load step at 2000 1/min

With activated EGR

Difference due to deactivated

drivability functions in HiL

simulation



LOAD STEP IN CLOSED-LOOP WITH ECU



Time / s

2 4 6 8 10 12 14 16

Air

ma

ss flo

w/ kg

/h

0100200300

Inje

ctio

n q

ua

ntity

/ m

g/s

tro

ke

0204060

Test bench

HiL

Bo

ost p

ressu

re/ b

ar

1.01.52.02.5

To

rqu

e r

eq

ue

st

/ N

m

0150300450600

Torque limit

Torque request limited

Torque to fuel quantity


Physical modelling of ambient

influences on engine system

behavior

Capable for function calibration

under extreme ambient

conditions

Prediction of physical limitations

for component protection



HIL TESTING AT ENGINE FULL LOAD, HIGH ALTITUDE (91 KPA, 23°C)

Nor

mal

ized

engi

ne to

rqe

/ -

0.0

0.2

0.4

0.6

0.8

1.0

trq_HiL_ECU trq_HiL_ECU_HA

Nor

mal

ized

inta

ke

man

ifold

pre

ssur

e / -

0.0

0.2

0.4

0.6

0.8

1.0

Normalized engine speed / -

0.0 0.2 0.4 0.6 0.8 1.0

Act_Intk_pres_HiL_ECU Des_Intk_pres_HiL_ECU Des_Intk_pres_HiL_ECU_HA Act_Intk_pres_HiL_ECU_HA

Nor

mal

ized

ai

r m

ass

flow

/ -

0.0

0.2

0.4

0.6

0.8

1.0

Act_m_air_HiL_ECU Act_m_air_HiL_ECU_HA

Nor

mal

ized

VN

T p

ositi

on /

-

0.0

0.2

0.4

0.6

0.8

1.0

Normalized engine speed / -

0.0 0.2 0.4 0.6 0.8 1.0

Act_VNT_pos_HiL_ECU Act_VNT_pos_HiL_ECU_HA

© by FEV – all rights reserved. Confidential – no passing on to third parties | 17

Use Case

DEVELOPMENT PROCESS USING VIRTUAL CALIBRATION

Engine model

re-calibrationVirtual calibration

phaseFinal calibration

and validation

First fire-up

engine test bench

European GT Conference 2018, Xia


Conclusion

Motivation:

Front-loading by XiL-based virtual calibration

Model transfer from concept-study to system calibration

Demonstration:

0D crank-angle resolved engine model vs. detailed 1D gas-exchange engine model

Offline verification with engine test bench measurement data

Online validation in closed-loop with ECU on HiL test bench designed for virtual calibration

The capability of crank-angle resolved engine model for HiL simulation (ECU-in-the-loop) and virtual calibration has

been demonstrated


CRANK-ANGLE RESOLVED REAL-TIME ENGINE MODELLING

A SEAMLESS TRANSFER FROM CONCEPT DESIGN TO HIL TESTING


Outlooks


ROADMAP FOR FEV/VKA VIRTUAL CALIBRATION USING GT-POWER ENGINE MODEL

Dev

elo

pm

ent

cost

ben

efit

Development time schedule

Today

GT-FRM model calibrated

and integrated into HiL

platform for virtual

calibration

Data based emission model

integration

Transient step tests

base combustion, aftertreatment

and OBD calibration/application

Transient simulation with full-

powertrain model

Transient application of major

virtual calibration tasks in closed-

loop with vehicle model

© by FEV – all rights reserved. Confidential – no passing on to third parties

F. Xia*, S. Lee, J. Andert

RWTH Aachen University

A. Kampmeier, T. Scheel, R.

Tharmakulasingam, M. Ehrly

FEV Europe GmbH

Y. Takahashi, T. Kumagai

FEV Japan

Feihong Xia

THANK YOU FOR YOUR ATTENTION!

Frankfurt, 08.10.2018

Reference:

Xia, F., Lee, S., Andert, J., Kampmeier, A. et al., "Crank-Angle Resolved

Real-Time Engine Modelling A Seamless Transfer from Concept Design to

HiL Testing," SAE Technical Paper 2018-01-1245,

2018, https://doi.org/10.4271/2018-01-1245.

Documents

CRANK-ANGLE RESOLVED REAL-TIME ENGINE MODELLING … · FOR HIL BASED VIRTUAL CALIBRATION Frankfurt, ... HP/LP EGR Reduced discretization level Same cylinder and turbocharger modelling