Development of a Practical Tool for Residual Gas ...€¦ · 3 M. Sellnau 7Dec09 The residual gas...

1 M. Sellnau 7Dec09

Development of a Practical Tool for Residual Gas Estimation in IC Engines

Mark Sellnau, James SinnamonDelphi Corp.

Carroll Dase, Kris Quillen, Matthew Viele Drivven Inc.

John Silvestri, Iakovos PapadimitriouGamma Technologies, Inc.

2009 GT-Suite ConferenceDecember 7, 2009Birmingham, MI

2 M. Sellnau 7Dec09

Contents

Objectives

Method & Validation

Implementation as Practical Tool

Residual Models for Advanced Engines

3 M. Sellnau 7Dec09

The residual gas (RSG) is the burned gas in the combustible mixture left over from the previous cycle Residuals are increasingly important for all types of current and future IC engines.– For Conventional SI engines, cam phasers can regulate RSG for

reduced NOx and FC (effectively replacing external EGR)

– For SI engines with Variable Valve Lift & Duration (VVA), RSG plays an important role to reduce pumping losses and NOx.

– For advanced HCCI engines, RSG is used to promote stable combustion. NVO and Rebreathing strategies are used to trap very high levels of RSG for these systems

– For advanced Premixed Diesel engines using LTC combustion modes, RSG can be used to simultaneously achieve very low NOx & PM

Background

4 M. Sellnau 7Dec09

Need to measure and control Residuals for virtually all types ofengines.

– Historically, Residuals have been one of the most difficult engine parameters to measure

Practical techniques are needed to measure/estimate residuals

– Accurate

– Inexpensive

– Wide range of engine operating conditions (speeds, loads, etc)

– During routine engine calibration testing

– Fast measurements in all cylinders for high-through-put calibration testcells

What is Needed?

5 M. Sellnau 7Dec09

Background

State-of-the-Art Methods

METHOD Difficulty/Expense Accuracy Operating Range Test Time

Direct cylinder gas sampling High High < 3000 RPM LongWith CO2 measurement < 7 bar NMEP

Detailed well calibrated High Good / Poor All / Most multi-cylinder simulation (depends on (depends on Medium(validated) model quality) model quality)

Detailed single-cylinder simulationWith measured port or pipe pressures Medium Very Good All < 1 min/cylapplied as boundary conditions

Proposed Method: Low: requires onlyCyl. Pres Measurements with standard test cell Very Good All < 1 min all Simple Single-Cyl Simulation cyls

METHOD Difficulty/Expense Accuracy Operating Range Test Time

Direct cylinder gas sampling High High < 3000 RPM LongWith CO2 measurement < 7 bar NMEP

Detailed well calibrated High Good / Poor All / Most multi-cylinder simulation (depends on (depends on Medium(validated) model quality) model quality)

Detailed single-cylinder simulationWith measured port or pipe pressures Medium Very Good All < 1 min/cylapplied as boundary conditions

Proposed Method: Low: requires onlyCyl. Pres Measurements with standard test cell Very Good All < 1 min all Simple Single-Cyl Simulation cyls

6 M. Sellnau 7Dec09

Develop an accurate METHOD to measure/estimate RSGImplement in a practical TOOL that can be easily used by calibration teams

Develop an accurate controls-oriented residual MODEL for integration in EMS

Objectives

7 M. Sellnau 7Dec09

Process & Dataflow: RSG Estimation & Model Calibration

Test Engine Residual Estimation Tool (RET)

DA

Q H

ardw

are

(Nat

Inst

)

Dat

a Lo

ggin

gSo

ftwar

e (L

abvi

ew)

T_intk_manP_intk_man

P_exh_manT_exh_man

Pcyl (1-8)Crank Enc

Tim

e-A

vg

Optimizer(Labview)

1-cylSimulation(GT-Power)

Est. Method

Residual ModelCalibration Macro

(Matlab)

Table of Resid vs.RPM, ICP,ECP,Pexh/MAP

Tables of ModelConstants

ProductionEngine ECU

ResidualModel

AirflowMeasurements

Cam PositionsControl

Algorithms• Spark Timing• SS & Transient Dilution Control

• Valve Lift & Timing• Fueling• NOx Models, etc

Simple EngineModel includg VL Profiles

8 M. Sellnau 7Dec09

MethodSinnamon, J. and Sellnau, M.,”A New Technique for Residual Gas Estimation and Modeling in Engines,” SAE 2008-01-0093.

Sellnau, M. et al., “Development of a Practical Tool for Residual Gas Estimation in IC Engines,” SAE 2009-01-0695.

9 M. Sellnau 7Dec09

Mtrap = Mair + Mfuel + Megr + Mresid = (Pcyl * Vcyl) / (R * Tcyl)

Measured

Apply the equation of state for cyl contents at intake valve closing

Calculate

Method to Calculate Residuals

result

RSG (mass %) = Mresid / (Mair + Mfuel + Megr +Mresid)

10 M. Sellnau 7Dec09

Ignore the complex pressure & flow pulsations during gas exchangeMethod to Calculate Residuals

Utilize simple single-cyl Simulation (Gamma Technologies, Inc)Couple Simulation to an Optimizer that iteratively adjusts burned mass so that:

> Simulated Airflow = measured Airflow> Simulated Pcyl = measured Pcyl

At convergence, the burned gas quantity is known

Multi-CylTest Engine

AirflowMeter

Mair = airflow rate

Tair = intake air temp

Pcyl

OptimizerSingle

CylinderSimulation

CADCrank

Encoder

Residual Estimator

Texh = exhaust temp

Fit real-time capablemodel for EMSResidual

Dataset

Measurements from Engine

ICP, ECP

Multi-CylTest Engine

AirflowMeter

Mair = airflow rate

Tair = intake air temp

Pcyl

OptimizerSingle

CylinderSimulation

CADCrank

Encoder

Residual Estimator

Texh = exhaust temp

Fit real-time capablemodel for EMSResidual

Dataset

Measurements from Engine

ICP, ECP

Patent Pending


Validation


Validation using In-Cyl CO2 Sampling Technique

Cambustion CSV500In-Cylinder Sampling System

SampleValve

Glow PlugAdapter

VacPump

HeatedSample Line

Temp Controller

PurgeValve

Sample Valve

SampleBlock

CombustionChamber

SampleTube

Timing Control Unit & Drivers

CrankEncoder

Spark Plug

Glow PlugAdapter

PC & Software

GasChromatograph

Metering Valve

HeatedBoost Pump

HeatedBoost Pump

4-Way Heated Valve

4-

Exhaust

or

HeatedSample Line

CalibrationGases

Back Pressure Regulator

Flow Meter

Vent

Flow MeterFlow Mete

VacPump

HeatedSample Line

Temp Controller

PurgeValve

Sample Valve

SampleBlock

CombustionChamber

SampleTube

Timing Control Unit & Drivers

CrankEncoder

Spark Plug

Glow PlugAdapter

PC & Software

GasChromatograph

Metering Valve

HeatedBoost Pump

HeatedBoost Pump

HeatedBoost Pump

HeatedBoost Pump

4-Way Heated Valve

4-

Exhaust

or

HeatedSample Line

CalibrationGases

Back Pressure Regulator

Flow Meter

Vent

Flow MeterFlow Mete

Diesel Hydra

Built test apparatus with emphasis on accurate measurement of residual gas levelsBest known technique for validation


Validation of Method

0

10

20

30

40

50

60

0 10 20 30 40 50 60Measured (CO2) Residual [%]

Estim

ated

Res

idua

l [%

]

Homogeneous DI Gasoline (Prince)

Single-Cyl Diesel, Neg Overlap

+/- 2 %

Good validation of METHOD over wide range of residuals (+/-2% RSG) Gasoline engine with Cam Phasing and TurboLean diesel engine with negative valve overlap and boost


Implementation as Practical Tool


RSG Estimation TOOL (RET)

Cyl Pressure Inputs

Crank Encoder

Thermocouples

UserInterface

• Airflow• Manifold Pres• Cam Sensor

AttributesBenchtop DeviceServices 8-cyl engineHardware: National Instruments PXi

Dual-core PCNI DAQ ModuleDual-Quad Core Processor

Sftwr:Coded in LabviewSingle-cyl GT Power

Interface & Communications: GUI (user)LAN (testcell & engine control)


RET Architecture with Multi-Core Processor

Dual Quad-Core Server8-processors with GTP simul for 8 cylinders

FPGAModule

ThermocoupleModule

- - - - -

Thermocouples

Crank Encoder,Cam Wheels

- - - - - - - - -

Cylinder PressureTransducers

Dual-CorePC

A/D ConverterA/D Converter

BNC ConnectorModule

PXI ChassisR

E-C

AM

LI-CA

M

LE-C

AM

RI-C

AM

360 PPR

1 PPR

PIN

T

PE

XH

-R

MA

P

FUEL

MA

T

PE

XH

-L

AIR

AFR

Time Average Signals

A/D Converter

Estimates Residual(runs optimizer & GT-Power Simulations simultaneously)

Controls Data Acquisition,Stores Raw Data


RET Monitoring during Data Acquisition

Monitor data logging progress. Inspect logged data for quality.

CombParams

Temps

Avg PcylAll Cylinders

Look forMisfires

(IMEP, PP)

CamPhase

Air, Fuel FlowManifold Pres


Benchmarking Speed Tests: Multi-Core RET

Processing speed target achieved with Multicore Processor

0

25

50

75

100

Original RET(Apr08)

Multi-Core RET(Nov08)

Improved RETOptimizer

Proc

essi

ng T

ime

(s) ~90 s

1-Cyl of Data

~95 s8-Cyl of Data

~50 s8-Cyl of Data

Target: 60 sec 8-Cyl of Data

Improved Optimizer

Code


Residual Gas Model for EMS


APPLICATION on V6 GDi Engine: RSG Model Calibration & Audit

Calibration Test PointsRPM = 1200,1600,2000,2400,2800,3200Intake Phaser (ICP) = 0,10,20,30,40Exhaust Phaser (ECP) = 0,10,20,30,40Pres Ratio (Pexh/MAP) = 2.9,2.3,1.8,1.5,1.3,1.1788 points processed using RET

Test Engine(GDi V6)


Residual Model

Coefficient TablesAt Each RPMIntake

Phase

ExhaustPhase

2-D TableA0

2-D TableA2

2-D TableA1

A0

A2

A1

Calculate RSG

RSG= fnc( A0, A1, A2, Pexh/MAP)

MAP Pexh

RSG Estimate

For any given RPM

Calib Macro used to determine Coefs from test data

-15

-10

-5

0

5

10

15

0 10 20 30 40Actual %Residual

Res

idua

l Err

or

Simple form of Residual Model Applies to Homo-stoich engines with DICPLookup table based with simple functionalRSG =f (RPM, MAP, Pexh, ICP, ECP)

Std. Dev. = 0.53% RSG

22 M. Sellnau 7Dec095 10 15 20 25 30 35 40 45

5

10

15

20

25

30

35

40

45

RET Measured Residual (%)

EC

U C

alcu

late

d R

esid

ual (

%)

p ,

5 10 15 20 25 30 35 40 455

10

15

20

25

30

35

40

45


EC

U C

alcu

late

d R

esid

ual (

%)

5 10 15 20 25 30 35 40 455

10

15

20

25

30

35

40

45


EC

U C

alcu

late

d R

esid

ual (

%)

5 10 15 20 25 30 35 40 455

10

15

20

25

30

35

40

45


EC

U C

alcu

late

d R

esid

ual (

%)

RSG Model Fit to Calib Data

1200 RPM 1600 RPM 2000 RPM

2400 RPM

5 10 15 20 25 30 35 40 455

10

15

20

25

30

35

40

45


EC

U C

alcu

late

d R

esid

ual (

%)

p

5 10 15 20 25 30 35 40 455

10

15

20

25

30

35

40

45


EC

U C

alcu

late

d R

esid

ual (

%)

p2800 RPM 3200 RPM

Graphs show RSG Model output as fnc of RET RSG during testsResults indicate <+/-2% RSG max error over full op. range

Std Dev: 0.28

Std Dev: 0.3Std Dev: 0.4Std Dev: 0.50

Std Dev: 0.29Std Dev: 0.35


Enhanced RSG ModelEnhanced RSG model using SPM model techniques– RSG = f (RPM, MAP, ICP, ECP, AFR, EGR) – Stratified-Lean engines with DICP, adv HCCI, Diesel, other

Estimated model accuracy: ± 1-2 % based on 95% CI

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35

Observed RSG [%]

Pred

icte

d R

SG [%

]

Data PointsLinear95% CI95% CI

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35

GTP Simulated Residual [%]

Pred

icte

d R

esid

ual [

%]

DataLinear

RPM: 1000 - 3000 MAP: 0.3 – 0.95 barAFR: Stoich - 30EGR: 0 – 40 %ICP : 0 – 60 degECP: 0 – 60 deg

Very wide range for input parameter values.

Need more data at high dilution.

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35


Pred

icte

d R

esid

ual [

%]

DataLinear




95% Confidence Interval = +/- 1.0 %(same as previous stoich, EGR=0 model)

0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35


Pred

icte

d R

esid

ual [

%]

DataLinear




0

5

10

15

20

25

30

35

0 5 10 15 20 25 30 35


Pred

icte

d R

esid

ual [

%]

DataLinear




95% Confidence Interval = +/- 1.0 %(same as previous stoich, EGR=0 model)

Actual Residual (%)

Res

idua

l Mod

el (%

)


Residual Estimator Tool

Developed and validated new method to estimate residuals Implemented in a practical Tool

National Instruments hardware with Multicore ProcessorsDemonstrated method on several engine types

DISI with DICP and VVAStratified-Lean GDiDieselGDi Turbo

Calibrated RSG modelsSimple Model (RPM, MAP, Pexh, ICP, ECP)Enhanced Model (Lean with EGR and DICP)

Good accuracy of +/-2% over operating range

Summary


Questions?

Thank you.

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Development of a Practical Tool for Residual Gas ...€¦ · 3 M. Sellnau 7Dec09 The residual gas...

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