2015 doe vehicle technologies program review · algorithm development. validation . ......

DGS-ES | 04-10-2015 | © 2015 Robert Bosch LLC and affiliates. All rights reserved.

2015 DOE Annual Merit Review REGIS

Diesel Gasoline Systems

Claus Schnabel (PI)

Award: DE-EE0005975 Sensors and Ignition Project ID: ACE091 Robert Bosch LLC

2015 DOE Vehicle Technologies Program ReviewWashington, D.C.

June 11, 2015

This presentation does not contain any proprietary, confidential, or otherwise restricted information1




Project OverviewPartners

Timeline

US Department of Energy

Robert Bosch LLC

Clemson University

Oak Ridge National Lab

Target is to develop an Intake Air Oxygen (IAO2) sensor which directly and accurately measures the oxygen concentration in the intake manifold and demonstrate its potential.

Barriers are• Inadequate data on requirements and risks

concerning sensing with IAO2 • Control Strategies utilizing IAO2 sensing

$4,446,686 – Total Project Budget$2,750,000 – DOE Funding$1,696,686 – Partner Funding

$4,137,184 – Actual expenditure (as of 03/2015)$2,506,501 – DOE Funding$1,630,683 – Partner Funding

$ 309,502 – Remaining (as of 03/2015)$ 243,499 – DOE Funding$ 66,003 – Partner Funding

Project Overview REGIS

Sensor Development

Baseline Sensor EvaluationDesign Development

Design DevelopmentValidation

Validation

System Evaluation

cEGR System EvaluationRequirements Sensor

Demonstration of potential

cEGR Control StrategyControl Algorithm Development Validation

2013-Phase I 2014-Phase 2

Budget

Target & Barriers

2015-Phase 3

2




Objectives and RelevanceObjectives• Develop an Intake Air Oxygen (IAO2) sensor which directly and accurately

measures the oxygen concentration in the intake manifold

• Demonstrate the potential of the sensor in combination with system adaptation and cEGR control strategies in a target engine application

Relevance of cEGR• cEGR enables improved fuel economy in most driving conditions

(on and off cycle) supporting the mainstream trend of Downsizing

• Improvement of up to 5% in engine peak thermal efficiency

• Other future combustion technologies will utilize cEGR

Relevance of IAO2• IA02 aims at providing a significant improvement in control accuracy of

cEGR to maximize the fuel economy potential of the system

3




Approach - REGIS

Sensor Development and Design

Controls & Software

System evaluation

Development of an IAO2 sensor for EGR control and demonstration of benefits

4




Collaborators and Partners

System level evaluation cEGR Control Development Proof of Potential

Funded by DOE 430 T USDOwn Funding 115 T USD

Derivation of requirements Development and Validation Sensor Built of Sensor Prototypes Validation Control Strategy

Funded by DOE 2,140 T USDOwn Funding 1,582 T USD

Advanced testing support Thermodynamics cEGR

Funded by DOE 180 T USDOwnFunding 0 T USD

5




Milestones & Summary of Technical AccomplishmentsSensor Development

Baseline sensor characterization

Improve sensor mounting and ECU connector design; build prototypes

Sensor development for functional robustness over lifetime; build prototypes

Concept for 2nd generation IAO2 elementSystem Evaluation

Baseline system characterization (engine testing and simulation)

Assessment of system risks and requirements for sensor (intake conditions, controls)

Investigate impact of sensor location on sensor performance and requirements

Control Development

EGR estimation algorithm development

Control-oriented model for in-cylinder EGR prediction

Demonstration of sensing benefits

Engine simulation to demonstrate sensor benefits

• Demonstration of improved sensor functionality and robustness

• Demonstration of potential for fuel economy improvement and emissions performance

with IAO2 compared to a model-based EGR control strategy using rapid prototyping

black: completed 2013white: completed 2014

6




IAO2 Motivation

IAO2 ∆p

Accuracy over lifetime

HW Robustness

Dynamic

Cost

Risk

Calibration effort

• Elevated EGR rates requiredeven at part load to achieve highEGR rates at high load due to aircharge system dynamics

• Near unity pressure ratio with LP-EGR at low flows is challengingfor flow modeling and controlswith differential pressure sensor

Significant portion of drive cycle operating area with small pressure differential across EGR valve and cooler (< 5 mbar)

Sensing Alternatives for EGR Determination

IAO2 is a key enabler for maximizing the benefits of LP cooled EGR

7




50m

m

37.5

mm

50mm hole spacing30

mm

M18

2x 6

.75m

m

16.2mm Mounting Hole

LSU IM1 comparison to LSU 5.1 (diesel exhaust sensor)

LSU IM1 primary application is LP cEGR Gasoline and Diesel application

Project was launched with focus on Gasoline applications

Requirements for HP EGR applications are considered but not decision drivers

LSU IM1 concept:

• Use of single cell wideband element (LSU 5.1 element)

• High communality to existing production

• Change to direct connector

• Optimize PT for intake application

• Directional PT to achieve better trade-offs

8




PT Optimization Parameters

RobustnessThermal

Shock

RobustnessSoot and other con-taminants

HeaterPower Demand

Response Time

9




0 500 1000 1500 2000 2500 30001000

1500

2000

2500

3000

Time [s]

Eng

ine

Spe

ed [R

PM

]

0 500 1000 1500 2000 2500 3000

5

10

15

20

Time [s]

BM

EP

[bar

]

Formation Deposition

0 25 50 75 100 125 150 175 200 225 2500

0.20.40.60.8

11.21.41.61.8

2

Time into Endurance Run [hours]

No

rma

lize

d R

esp

on

se T

ime

[-]

Stable response time

IAO2 fouling robustness testSoot robustness test cycle

• Phase 1: Bosch reference “Aggressive” PN generation cycle

• Phase 2: Low flow velocity cycle to “bake on” particulate matter

• Automated in-situ response time test with intake N2 purge each cycle

• Continuous 24/7 automated running• 25 sensors tested with 14 different

protection tubes for 250 hours

Test Calibration Parameters• 10 to >25% eEGR commanded over

entire engine map• High particulates induced by modified

injection timing

Stable T63 response time observed over entire test independent of protection tube design

10




Thermal Shock Testing

Results• Benchmarking of directional and non

directional designs

• Good thermal shock results are possible with non-directional and directional protection tubes

Test Method • New test method uses Bosch liquid sensor to

detect size and number of water droplets impacting sensor element

• Previous test method used sensor signal to evaluate the signal to noise ratio based on the cooling effect of water entering protection tube

High Thermal Shock Protection with a variety of directional and non directional designs

0

50

100

150

200

250

300

350

0.00

0.20

0.40

0.60

0.80

1.00

1.20

Non-direct1

Non-direct2

Non-direct3

Non-direct4

Directional1

Directional2

Directional3

Directional4

Wat

er D

ropl

et -

Num

ber

Wat

er D

ropl

et V

olum

e -A

vera

ge

Protection Tube

Thermal Shock Protection Tube Comparison

Avg Vol No. Drops

11




Example of Protective Tube evaluation

Selection criteria• Switch time• Heater power demand• Water thermal shock resistance• Soot durability

Example shown is a projection tube of current production and proven in the field

0100200300400500

50 100 200 400 600 8000 100 200

Heater Power Demand Switch Time Soot Durability

-5.0

5.0

15.0

25.0

50 100 200 400 600 800

12




Second Build and ValidationSecond Build completed in September 2014

Environmental Testing:• Thermal Cycling• Salt Water Submergence

Mechanical Testing:• Sine Vibration• Wideband Vibration

Purpose proof of robustness against environment:• Ensure sealing of components• Mechanical robustness of external and internal connections• Pre- and post- functionality of sensor

Results: No Design related failures

13




IAO2 AccuracyContributors of exhaust oxygen sensor LSU5.1 tolerance ± 3.5% @ λ=2.4:

Deviation from nominal value on air Humidity

Reduced tolerances for IAO2 sensor by improved pressure compensation: Online pressure measurement Pressure compensated air trimming Sensor specific k-value adaption Reduced pressure pulses

• Improved pressure compensation strategy established • Accuracy target of +/- 2% ΔO2/O2 can be reached• To check: Cross-sensitivities will have an impact on the accuracy depending on operating mode

total system error w/o electronics, w/o cross-sensitivity

14




Accuracy

• Various exhaust species have a significant effect on the LSU IM’s signal, especially at rich conditions

• Previous testing by ORNL and modeling of the exhaust species at engine operating points shows the total error this generates

• Using this data and measurements from the LTG engine the errors were reduced from >23% at extreme operating conditions to ±2.5% at all conditions-25.0%

-22.5%

-20.0%

-17.5%

-15.0%

-12.5%

-10.0%

-7.5%

-5.0%

-2.5%

0.0%

2.5%

5.0%

0.6 0.7 0.8 0.9 1 1.1

Rela

tive

Erro

r in

Mol

ar O

2 Co

necn

trat

ion[

%]

Exhaust Lambda [-]

LSU IM Uncompensated LSU IM Compensated

Cross Sensitivities Resulting from Exhaust λ Deviations

-0.14% 0.28% 0.10%

-0.05%

-2.30%

0.08%

1.37%

λ=1, cEGR=20%, T=20°C, 100% Relative Humidity

CO H2O vap H2O EGR H2 Hydrocarbon NO O2(EGR)

-0.13%0.68%

0.42%-0.05%

-2.16%

0.08%

1.37%

λ=1, cEGR=20%, T=40°C, 100% Relative Humidity


-7.86%

0.11%0.21%

-2.70%

-2.63%

0.08%0.82%

λ=0.7, cEGR=20%, T=20°C, 100% Relative Humidity


TotalError:

-0.65%

TotalError:

-0.21%

TotalError:

-12.0%

15




Real time testing at Clemson University has validated EGR correction and transport sub-systems

6

8

10

12

14

16

18

20

22

24

0

0.2

0.4

0.6

0.8

1

1.2

47 52 57La

mbd

a [-]

Time [Sec]

Lambda Exh TurbineLambda Exh IMOSEGR% Corrected with Exh LambdaEGR% Corrected with IMOS LambdaUncorrected EGR %

EGR

[%]

Exhaust Transport Time

Rich Correction

Transport Corrections

Phase 2 objectives for sensor correction and transport delay are complete

Intake O2 Sensor

Exhaust O2 Sensor

EGR transport and sensor correction control models are validated

EGR and Species Transport Models

EGR Valve

Controls

16




Low pressure EGR control system

Transport models (completed)

EGR and Exhaust flow models (on-going)

EGR Valve Control (on-going)

IMOS signal correction (in final validation)

tdelay = 𝑳 𝑷 𝑨𝑹 𝑻 �̇�

�̇� 𝒕𝒉=𝑪𝑫 𝑨𝒕𝒉𝒑𝟎

𝑹 𝑻𝒐

𝒑𝑻𝒑𝟎

𝟏𝜸Ψ

𝒑𝑻𝒑𝟎

020

4060

80100

0.80.85

0.90.95

1

-50

0

50

100

150

200

Pressure ratioValve angle [deg]

Flow

rate

[kg/

hr]

Engine out emissionsprediction

IMOS sensitivity

ETAS Rapid Control Prototyping

BOSCH MED17 Engine ECU

Adaptive Control

Real-time Engine Testing

Control models will be delivered to BOSCH during Phase 3 for integration into ECUs

Phase 2 Phase 3

Control models will be delivered to Bosch during phase 3 for ECU integration

Controls

17




Concept: Second Generation Sensor

• Potential to measure multiple species• Newly designed measurement concept• High water load robustness• Stable in lean conditions• Low pressure dependency• No humidity dependency• Lower heater power optimized for intake manifolds• Stabilized sensor temperature at high, cold flow rates• Flexibility regarding protection tube design • Two single cell sensors: 8 wire sensor concept• Free choice of sensor connector

18




Future Directions REGISSensor Development

• Develop and demonstrate sensor functional robustness over lifetime• Investigate concept for 2nd generation IAO2 element

Demonstration of sensing benefits

• Demonstration of improved sensor functionality and robustness• Demonstration of potential for fuel economy improvement and emissions

performance achieved with IAO2 compared to a model-based EGR control strategy using rapid prototyping

19




Summary REGISRelevance of Intake Air Oxygen (IAO2) sensing • Directly and accurately measures the oxygen concentration in the intake manifold • Enables accurate and robust EGR control for future engine concepts utilizing cEGRApproach• Develop requirements • Design sensor solutions • Develop robust cEGR controlsTechnical Accomplishments Developed and demonstrated improved sensor mounting and ECU connector design Identified sensor design for improved thermal shock robustness and response time Assessed system risks and requirements for sensor (intake conditions, controls) Identified sensor location for best sensor performance and cEGR control Developed cEGR estimation algorithm Develop control-oriented model for in-cylinder EGR prediction Future Work• Develop and demonstrate sensor functional robustness over lifetime• Investigate concept for 2nd generation IAO2 element• Demonstrate sensing benefits

Tools• Targeted engines• Flow benches• Simulation studies

20




Technical Back Up slides

21




Choice of Sensing Element• High water load robustness• Stable in lean conditions• Low pressure dependency• High soot robustness (optimized for Diesel engines)• Strong heater optimized for Diesel engines• Stabilized sensor temperature at high, cold flow rates• Flexibility regarding protection tube design • Single cell sensor : Compact 4 wire sensor concept

Free choice of sensor connector

Coating for thermal shock protection

Inner ElectrodeDiffusion Barrier

ZrO2

O--

Pumping Voltage

AirReferenceElectrode

ExhaustGas

22




IAO2 Mounting Position

IAO2 mounting post-compressor is the best solution for durability, functionality and power consumption

Sensor Location

2000/2 3000/10

V8 5.0 NA

6000/9

2000/2

I4 2.0 GTDI

2000/15

Response Time [ms]

Overlapping regions where response time

and heater power requirements are met

5000/204000/16

2000/8

Gas Velocity

Res

pons

e Ti

me

23




IAO2 Mounting Position

Sensor Location

Gas Velocity

Res

pons

e Ti

me

IAO2 mounting post-compressor is the best solution for durability, functionality and power consumption

Significant margin to condensation

conditions only for Pre-CAC position

24




Technical / technology

1 Sensor not robust for intake

2 Other methods for controlling EGR are better

3 Sensor can lead to ignition of intake gas

Development risk

4 Sensor accuracy not sufficient

5 Sensor costs higher than estimated

Competencies / Know-how

6 Unable to package sensor for intake

max

min

min max

prob

abili

ty

Potential risk

1

4

2

5

6

36

1

4

5 3

2

HC Cross Sensitivity in Gasoline Applications remain a challenge

Start of Project today

Technical Risk Assessment

25




Assessment of Ignition RiskEliminate the very low ignition risk by one of

the following strategies:• Temp. control and heater diagnostic

Check sensor heater power demand withengine operating conditions

• Define purge conditionsAvoid explosive mixtures by avoidingpurging during tip-out (check valves intank purge lines after tip-out)

• An ignition is very unlikely and if with minor impact on the intake manifold (loss in boostdue to intake manifold damage)

• Elimination of the low ignition risk possible by simple application rules• No LSU IM1 design adjustments necessary to eliminate ignition risk

700

750

800

850

900

950

1000

1050

1100

Gasoline Methane Propane Isopentane N-Pentane

Min

imum

Obs

erve

d Ig

nitio

n Te

mpe

ratu

re (C

)

• Define mounting positionMounting of LSU-IM1 before throttlein case of T/C -systems

Minimum observed ignition temperature 929degC at worst case conditions: • Stoichiometric mixtures• Low flow conditions• Direct exposure to the hot ceramic element

Sensor operating temperature

26

2015 doe vehicle technologies program review · algorithm development. validation . ......

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