Intake Air Oxygen Sensor

2014 DOE Annual Merit Review REGIS 2014 DOE Vehicle Technologies Program Review

Washington, D.C. June 19th, 2014

Claus Schnabel (PI)

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

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

1 restricted information 2014 DOE Annual Merit Review REGIS Project Overview Target & Barriers Partners Target is to develop an Intake Air Oxygen (IAO2) sensor which directly and accurately measures the US Department of Energy oxygen concentration in the intake manifold and demonstrate its potential. Robert Bosch LLC Barriers are ! Inadequate data on requirements and risks Clemson University concerning sensing with IAO2 ! Control Strategies utilizing IAO2 sensing Oak Ridge National Lab Budget Timeline

$4,446,686 – Total Project Budget 2013-Phase I 2014 -Phase 2 cEGR Control Strategy $2,750,000 – DOE Funding Control Algorithm Development Validation $1,696,686 – Partner Funding

$1,781,072 – Actual expenditure (as of 12/2013) System Evaluation cEGR System Evaluation $1,096,084 – DOE Funding Demonstration of potential Requirements Sensor $684,988 – Partner Funding

$2,665,614 – Remaining (as of 12/2013) Sensor Development $1,653,916 – DOE Funding Baseline Sensor Evaluation Design Development Validation $1,011,698 – Partner Funding Design Development Validation

2 GS-SI/ENG2-NA | 6/19/2014 | © 2013 Robert Bosch LLC and affiliates. All rights reserved. 2014 DOE Annual Merit Review REGIS Objectives and Relevance Objectives  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

2014 DOE Annual Merit Review REGIS Collaborators and Partners

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

Funded by DOE 2110 T USD Own Funding 1582 T USD

 System level evaluation cEGR  Advanced testing support  Control Development  Thermodynamics cEGR  Proof of Potential Funded by DOE 180 T USD Funded by DOE 460 T USD Own Funding 0 T USD Own Funding 115 T USD

5 2014 DOE Annual Merit Review REGIS Milestones & Summary of Technical Accomplishments Sensor 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 element System 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

6 2014 DOE Annual Merit Review REGIS IAO2 Motivation CooledLTG EGR LP-EGR Relative Relative BSFC BSFC Delta [%]Delta [%] 0 Region with 20 small pressure

differential 15 -1 across EGR

valve (pressure 10 ratio is near BMEP [bar] -2

unity) 5

-3 1500 2000 2500 3000 Engine Speed [RPM]

Sensing Alternatives for EGR Determination  Near unity pressure ratio over EGR valve in region with greatest IAO2 ∆p

Accuracy (long term) impact on fuel economy HW Robustness  Near unity pressure ratio with LP- Dynamic EGR is challenging for flow Cost modeling and controls with Risk

Calibration effort differential pressures sensor

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

7 2014 DOE Annual Merit Review REGIS IAO2 Control Development

Low ∆p 0.90.9 1 EGR % Known Here! Air-to-fuel ratio challenge 0.950.95 0.85 0.85 20 0.9 0.9 transients require for system 0.9 modeling of Transport 0.950.95 Delay #1 model 0.970.97 0.9 0.9 0.85 0.85 15 0.9 0.950.95 0.970.97 Long term 0.990.99 0.9 0.9 10 0.8 BMEP [bar] accuracy 0.990.99 0.970.97 0.95 0.95 major 0.990.99 Significant part of the 5 map shows a 0.8 challenge 11 pressure ratio > 0.95

0.7 1000 2000 3000 4000 5000 Speed [RPM] Transport

10 delays

7.5 GT-Power

IAO2 able to Mass Flow [kg/hr] 2.5 close model 0 gap 14 16 18 20 22 Physics-based Real-time Time [s] Measured EGR Mass Flow Modeled EGR Mass Flow Requested EGR Mass Flow control models validation

8 2014 DOE Annual Merit Review REGIS IAO2 Accuracy 3.0% Range of Water from EGR 2.5%

2.0% Exhaust 1.5%

1.0% Range of Water in Concentration [%] Ambient Air

Deviation in Sensed Molar 0.5%

0.0% 0 2.5 5 7.5 10 12.5 15 17.5 Concentration of Water [%] 21% Oxygen 7% Oxygen

Error in EGR calculation by neglecting humidity 130% 20 120% 18 110% 16 100% 14 T=40 F 12 T=50 F 90% T=60 F 10 80% T=70 F

EGR Error [%] Error EGR 8 T=80 F 70% T=90 F 6 T=100 F 60% 4 T=110 F Change in Sensor Sensor Changein Signal[%] 50% 2 40% 0 20% 30% 40% 50% 60% 70% 80% 90% 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 Relative Humidity [%] Absolute Pressure at Sensor [mBar]

Target ±1% ∆O2/O2 2013 2014 2015 High Pressure EGR Low Pressure EGR Multi-faceted approach needed to meet desired accuracy targets.

9 2014 DOE Annual Merit Review REGIS

IAO2 Mounting Position Response Time [ms]

V8 5.0 NA

2000/2 2000/8 3000/10 6000/9 ResponseTime I4 2.0 GTDI Gas Velocity 2000/2 2000/15 4000/16 5000/20

Overlapping regions Sensor Location where response time and heater power Heater Power [W] requirements are met 100 20 80 16 16 15 10 60 1212 24 24 5 diameter [mm] 20 20 40 0 200 400 600 800 1000 massflow [kg/h]

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

10 2014 DOE Annual Merit Review REGIS Technical Risk Assessment Potential risk min max max 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 1 4 Sensor accuracy not sufficient 4 3 5 Sensor costs higher than estimated

probability 4 1 5 6 3 Competencies / Know-how 5 6 Unable to package sensor for intake 2 2

6 Start of Project today min

Ignition of intake gas is key remaining risk after Phase 1

11 2014 DOE Annual Merit Review REGIS

Ignition Study at Oak Ridge National Lab 150 Gas Temp (C) Sensor Temp (C) 130 80

110 (C) 90 Fuel flow started at 60 sec. (Stoichiometric, E0 Gasoline)

70 Gas Temp (C) 70 Derived Sensor Temp 50 850 0 30 60 90 120 150 180 210 60 Time (sec)

Result 50  Ignition can occur at elevated gas temperatures and with aged sensor 40 Initial Gas Temperature (C) Temperature Gas Initial 50 C Next Steps  FMEA 30 Derived Sensor Temperature (C)  Study to understand ignition risk for Circles = E0 Gasoline failure modes identified by FMEA Square = 100% non-denatured ethanol  Identify measures in sensor design to arrest flame kernels Blue, empty = no ignition (<10C Delta Gas T) Red, filled = ignition (>10C Delta Gas T)  Propagate engine design with purge entry upstream of sensor Temperature range of new sensor for critical operation points

12 2014 DOE Annual Merit Review REGIS Choice of Sensor Concept

Develop Product Requirements Number of concepts evaluated

Derive Functions Contacting 25 Search for Solution Principles

Subdivide into Modules and Design Elements Housing 10

Design All Elements Derive Process Chain Analyze and Adjust Design Production AnalyzeProzesse and Adjust analysieren, Processes (Cause Effect Relationships Processes (Causeabgleichen Effect Relationships (WzH. Mounting 3 Design to Function) ProcessDesign/Prozess) to Design)

Evaluate Protection Tube 4 Decide

 Use single cell wideband element

Sensor Concept:  Change to direct connector  Find high commonality to existing production

 Optimize protection tube for intake application

13 2014 DOE Annual Merit Review REGIS 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 Coating for thermal  Single cell sensor : Compact 4 wire sensor concept shock Free choice of sensor connector protection

Pumping Voltage ZrO2 Reference Diffusion Barrier InnerElectrode O-- Electrode Air Exhaust Gas

Thermal mapping at rated power conditions

Results from thermal mapping of component  Component temperatures are in acceptable range  Recommendation for calibration derived

Development goal for first build robustness of plastic connector/ housing achieved

15 2014 DOE Annual Merit Review REGIS Validation Results of First Build

LSU IM1 Connector Housing Thermal Aging Leak Test Results 1000 Cycles / Hours

Leak Rate No leakage in sealed parts C1S C2S C3S C4S C5S B1S B2S B3S B4S B5S

Unsealed Sealed

Sealing of plastic connector to metal housing after thermal aging achieved

16 2014 DOE Annual Merit Review REGIS Protection Tube Optimization - Tool Box

Flow bench DFFS

Requirements 3-d

Operating Mode Response Time

Engine Speed cEGR cEGRrate,des eEGR Valve EGR Valve Set CFD cEGR Valve Coordinator Flow Model Position Control Engine Load Heater Power Demand Thermal Shock Exhaust Texh Pressure/ Temperature Contamination Pexh Model cEGR cEGR LSU IM Pressure Aging Intake O2 Pint Model Model Sensing EGR Valve Position

Intake Air Flow

Intake Oxygen Concentration

17 18 Protection Tube (PT) Optimization Optimization Tube (PT) Protection 2014 DOE Annual Merit Review REGIS Review Merit Annual DOE 2014

 tubeoptimization protection Results from Thermal Shock Robustness parameters. feature of optimization from increased has PT performance Existing Bosch Directional Target exceed performanceto benchmark of achieved. patent was A1.0 Directional B1.0 Directional B1.2 Bechmark Patent Benchmark Patent Directional B1.2 Directional B1.0 Directional A1.0 Existing Bosch

Heater Power (W) Heater Power (W) 100 ms Lowpart flow/ load conditions

1 W Switch TimeSwitch (ms)

2014 DOE Annual Merit Review REGIS Future Directions REGIS

Sensor Development  Develop and demonstrate sensor functional robustness over lifetime  Build production intent prototypes  Investigate concept for 2nd generation IAO2 element System Evaluation  Understand risk in vehicle for ignition  Understand signal off-set caused by HC’s found in intake during vehicle operation Control Development  Control-oriented model for in-cylinder EGR prediction 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 2014 DOE Annual Merit Review REGIS Summary REGIS Relevance 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 cEGR Approach Tools  Develop requirements  Targeted engines  Design sensor solutions  Flow benches  Develop robust cEGR controls  Simulation studies Technical 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 Future Work  Develop and demonstrate sensor functional robustness over lifetime  Investigate concept for 2nd generation IAO2 element  Develop control-oriented model for in-cylinder EGR prediction  Demonstrate sensing benefits

2014 DOE Annual Merit Review REGIS

Technical Back Up slides

21.00% 0.60% 0.5%

0.40% 20.00% 0.0% 0.20% 19.00% -0.5% 0.00%

18.00% -0.20% -1.0% Relative Error in O2 [%] 17.00% -0.40% Concentration [%] -1.5% Deviation in Sensed Molar

Measured O2 Concentration [%] O2 Measured Concentration 16.00% -0.60% -2.0% 15.00% -0.80% 0 200 400 600 800 1000 16.00% 17.00% 18.00% 19.00% 20.00% 21.00% Concentration [ppm] Absolute O2 Concentration [%] Reference O2 Values LSU IM Values Relative error in O2 from LSU IM NO (ppm) C3H6 (ppm) NH3 (ppm) 10

Ability to tolerate large errors in system metering 7.5  Production part tolerance 5  Aging of components 2.5  Modeling errors in calibration Mass Flow [kg/hr] 0 14 16 18 20 22 Long term adaptation possible over lifetime Time [s] Measured EGR Mass Flow Modeled EGR Mass Flow Requested EGR Mass Flow

22 2014 DOE Annual Merit Review REGIS Ignition Study Thermocouple  Introduce aerosolized fuel/air mixture to REGIS sensor  Fixed gas velocity (slow) ~1 m/s  Fixed air/fuel ratio (stoichiometric)  Fixed mixture temperature (50 -80 °C) Device body (3/4  Two fuels: E10 gasoline blend plus E85 blend inch stainless tube w/ insulation)  Vary sensor element temperature Test Sensor  Detect ignition with thermocouple measurement of gas temperature downstream of REGIS sensor

 Realization  Use of air assisted atomizer nozzle w/ preheated air  Air flow control using a mass flow controller  Fuel flow control using a syringe pump  Heating of air and surfaces around the injector to maximize fuel vaporization Air assisted nozzle minimize condensation on surfaces Preheated air inlet

23 24 Heater Power (W) Protection Tube Optimization Optimization Tube Protection 2014 DOE Annual Merit Review REGIS Review Merit Annual DOE 2014 50 ms 1 W

Protection tube optimization achieved targets for sensor performance sensor for targets achieved optimization tube Protection High Flow in engine part and medium load conditions engine part medium conditions and load in

Benchmark Patent Directional B1.2 Directional B1.0 Directional A1.0 Existing Bosch

Heater Power (W) 1 W 100 ms

Low Flow -

part load conditions load part

2014 DOE Annual Merit Review REGIS First Build Thermal Management

Engine off

Thermal mapping for hot soak showed component temperature in acceptable range

25 2014 DOE Annual Merit Review REGIS First Build and Validation First build completed in December 2013

Mechanical Testing: Environmental Testing:  Sine Vibration  Hot Soak  Wideband Vibration  Cold Soak  Vibrational Resonance  Thermal Cycling  Mechanical Shock  Salt Water Submergence  Drop  High Pressure Water Spray  Pendulum Swing

Purpose:  Ensure sealing of components Results:  No design related failures  Mechanical robustness of external and internal connections

 Pre- and post- functionality of sensor

First build validation completed in April 2014