GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 

### Stuart R. Smith

- Principal Investigator

GM Powertrain May 17, 2013

2013 DOE Vehicle Technologies Program Annual Merit Review Washington, DC 

# Lean Gasoline System Development for Fuel Efficient Small Car

Project ID: ACE063GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 2 

## TIMELINE

• Project start: May 2010

• Project end: Sept 2013

• Project duration: 3 yrs 3m

• Percent complete: 90% 

## BARRIERS

• Engine efficiency improvement >25%

• Engine controls to meet regulatory and consumer requirements

• Emission control hardware cost competitiveness



## BUDGET

• Total funding : $ 15,411,724

– DOE share: $ 7,705,862

– GM share: $ 7,705,862

– DOE Funding FY12 $3,014,435

– DOE Funding FY13 $276,308 

## PARTNERS

•

•

• 

# Lean Gasoline System Development

OverviewGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 3 

# Lean Gasoline System Development

Relevance

– Program Objective

25 % fuel economy improvement while meeting T2B2 emissions

 Lean Combustion

- Generate fundamental lean gasoline combustion comprehension and design guidelines that would support implementation

across multiple engine families

 Lean Aftertreatment

- Optimize a lean aftertreatment system that combines passive NH3 generation with active urea dosing for minimized urea consumption under lean operating conditions

 Lean Controls

- Develop engine and passive and active aftertreatment controls that work within production controls constraints to ensure compatibility with future ECU architecturesGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 4 

# Lean Gasoline System Development Approach / Strategy

– Targeted Efficiency Improvement

Advanced Dilute Combustion (direct injection, cool EGR)



### Lean Dilute Combustion (

closely

- spaced multiple pulse injection ) 

### Vehicle Integration (12V stop/start, active thermal management )



### Downsizing

(2.4L PFI to 1.4L DI Turbo)



### Projection **7.5% Projection**  **12.5% Projection**  **5%**

* Projections formulated from dynamometer and SG5 vehicle dataGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 5 

# Lean Gasoline System Development Approach / Strategy

– Technology Development PlanPhase 2RefinementPhase 3Optimization Aug 2013

1.4L Lean Downsize Boost Design & Build 2.2L SG5 NA Vehicle Integration & Calibration Downsize Boost Simulation

Gen 2/3 Passive SCR Development

Active SCR Development

Passive/Active SCR

S/S & ATM Integration

Demo 1.4L LDB Calibration Lean Boost Controls

FE Optimization Nov 2012 May 2013 May 2012GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 6 

### SG5 Fuel Economy Limitations

 Lean operation shows significant fuel economy improvement at light to medium loads  Needed to extend the lean operating range to higher loads



### SG5 Systems Refinement

 Enabled development of controls around lean

- stoich transitions  Enabled exploratory boost performance investigations  Enabled refinement of multiple aftertreatment systems 

# Lean Gasoline System Development Accomplishments

– Phase 2: SG5 NA Systems Refinement

 The SG5 NA engine would not meet FE targets. However, it enabled development of combustion system, lean aftertreatment (hardware and controls), and in

- vehicle engine controls and calibrationGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 7 

# Lean Gasoline System Development Accomplishments

– Phase 2: SG5 NA Fuel Economy Improvement

Fuel Economy Simulation

 BSFC data for high usage speed / load points from FTP tests used to project fuel economy improvements

 D ata does not include 12V Stop/Start and Active T hermal
M anagement which is projected to provide additional 4

- 6 % combined fuel economy benefit

 Good correlation between fuel economy projections and measured vehicle data
 SG5 NA Engine does not meet FE target Speed (RPM) Load (n-m) BSFC Improvement PFI to Lean NA
Idle 700 19 0% Zone 2 1335 27 17% Zone 3 1565 28 19% Zone 4 1805 29 18% Zone 5 1530 95 -1% Zone 6 1821 80 3% Zone 7 2250 101 0%
Zone 8 1410 51 18% Zone 9 1669 60 9% Zone 10 1461 114 0% Zone 11 1692 100 0%

Projected FE Improvement Measured FE Improvement City 12% 12%

Hiway 8% 7%

Combined 10% 10%UrbanHighwayGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 8 

# Lean Gasoline System Development Accomplishments

– Phase 2: Passive/Active Ammonia SCR System

Passive/Active Ammonia SCR System (PAASS)
 A portion of the NH3 is generated across three way catalyst with the remainder injected  The selected TWC volume and formulation optimize the NH3 generation during lean

- to

stoichiometric transitions

 The passive and active ammonia systems are combined to achieve the optimal aftertreatment to support lean and stoichiometric operation under all conditions 0 50 100 150 200 250 300

0 100 200 300 400 500 600 700

0 500 1000 1500 2000 2500Vehicle Speed [mph]Temps (DegC)

Time [sec] Temperatures for SCR 4 Brick System

- "Torpedo"

Torpedo 1 Torpedo 2 Torpedo 3 Torpedo 5 Torpedo 6 Torpedo 7 Torpedo 8 Torpedo 9 Vehicle Speed MS03007020

1/4/2013 MS04008344

SCR Torpedo 1 2 3 4 5 6 7 8 9 Post O2 sensor NOx sensor Urea Injector ~56.5” to front face of SCR 16.5

” TWC

- 1 SCR volume = 4.0L 4.66” round substrates (4 substrates x 1.0L)

Cu

- Fe

- Fe

- Cu

TWC

- 2 1.7 L Y

oval 1.0 L round

Mixe

rGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information *Diesel information is from T2B5 package

9 

# Lean Gasoline System Development Accomplishments – Phase 2 : Comparison with Diesel Vehicle

Aftertreatment
 In order to achieve FE targets, engine

- out NOx increases and the active urea system is incorporated to supplement the passive system
 Urea consumption is not linear with engine

- out NOx due to passive NH3 generation and TWC reductionGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 10 

# Lean Gasoline System Development Accomplishments – Phase 3: 1.4L LDB Combustion Optimization

 Transfer the desired combustion characteristics of the SG5 to the new LDB engine
 CFD analysis to simulate the spray pattern and in

- cylinder air fuel ratio distribution
 Flow bench to measure and modify swirl and tumble ratio on the new LDB engine Fuel Spray Analysis

In

- cylinder Fuel Equivalence Ratio Distribution Analysis Swirl & Tumble Flow BenchGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 11 

# Lean Gasoline System Development Accomplishments

– Phase 3: 1.4L LDB Engine Combustion Features

1.4L Boosted Stoich 1.4L LDB

 Fuel spray cone is targeted to the spark gap w/close

- space injections
 Injector is pulled upward and spark plug is moved downward

 LE2 piston bowl is modified to match SG5 NA piston bowl
 Piston crown is modified to result in 10.5 compression ratio

 Added low pressure cooled EGR system
 Moved TWC catalyst location for meeting T2B2 HC emission level

 Start with 1.4L boosted stoichiometric

- homogeneous combustion engine
 Modifications made to engine components to enable lean

- stratified operationGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 12 

# Lean Gasoline System Development Accomplishments

– Phase 3: LDB Engine Procured, Built & Installed

Charge & Exhaust System

 Compact turbocharger to support high EGR, low RPM performance

 Cooled low

- p ressure EGR with

gases taken downstream of the turbo

 Air

- to

- water charge a ir c ooler with independent low temperature coolant circuit & auxiliary pump

 Close Coupled TWC Catalyst integrated in turbine housing

 Four 1.4L Lean Downsize Boost (LDB) engines are designed, procured and built to support calibration, controls development, integration and fuel economy optimizationGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 13 

# Lean Gasoline System Development Accomplishments – Phase 3: LDB Boosted Lean Combustion

 The LDB engine delivers ~ 15% improvement in fuel consumption at 25 to 30 Nm
 The SG5 naturally aspirated engine lean stratified operation limit is ~85 Nm
 The LDB engine lean stratified operation limit is ~120 Nm, results in ~7% improvement in fuel consumption BSFC comparison: PFI to NA Lean to Lean Downsize BoostNormalized BSFCGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 14 

# Lean Gasoline System Development Accomplishments

– Phase 3: LDB Engine BSFC vs FSNOx Trade

- off

0 10 20 30 40 50 60

245 250 255 260 265 270 275 BSFC (g/kwh)FSNOx (g/kg Fuel) 245 250 255 260 265 270 275

0 10 20 30 40 EGR (%)BSFC (g/kwh) RPM 1669 BMEP 5.4 bar

RPM 1669 BMEP 5.4 bar 

## Lean Downsize Boost Engine Calibration S trategy:

 When the engine is running lean, small amount of EGR will not have significant impact on BSFC

 Small amount of EGR will have significant impact on engine

- out NOx emission

 One percent BSFC degradation point is selected to represent the best trade

- off calibration point 1%



###  Cooled EGR is added to reduce NOx emission until 1% BSFC degradation is observedGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 

### Targeted Efficiency Improvement
 Downsizing 7

- 8 %
 Dilute & Lean Combustion 12 -13%
 Total from Engine 19

- 21 %

 12V Stop/Start & Active Thermal Management 5 %

15 

# Lean Gasoline System Development Accomplishments – Phase 3: Vehicle Fuel Economy Projections

 The LDB engine in combination with 12V Stop/Start and Active Thermal Management is projected to meet the 25% fuel economy improvement target FE Projections: PFI to NA Lean to Lean Downsize Boost

Speed (RPM) Load (n-m) PFI to Lean NA PFI to LDB
Idle 700 19 0% 0% Zone 2 1335 27 17% 30% Zone 3 1565 28 19% 31% Zone 4 1805 29 18% 35% Zone 5 1530 95 -1% 7% Zone 6 1821 80 3% 9% Zone 7 2250 101 0% 7%
Zone 8 1410 51 18% 16% Zone 9 1669 60 9% 14% Zone 10 1461 114 0% 3% Zone 11 1692 100 0% 6%

City 12% 26%

Highway 8% 12%

Combined 10% 21% BSFC Improvement

Projected FE ImprovementUrbanHighwayGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 16 

### Passive/Active SCR

– LDB 1.4L Boosted  Apply as much as possible of the SG5 exhaust architecture on LDB engine.

NOx sensor Urea Injector 16.5” SCR volume = 4.0L 4.66” round substrates (4 bricks x 1.0L)

Cu

- Cu

- Cu

- Cu

Mixer 

# Lean Gasoline System Development Accomplishments

– Phase 3: Passive/Active Ammonia SCR System

0 50 100 150 200 250 300 350 400 450

1335 / 2.5 1565 / 2.5 1805 / 2.6 1821 / 7.1 1410 / 4.5 1669 / 5.4TWC Inlet Gas Temp

Engine Speed / BMEP 0 50 100 150 200 250 300 350

1335 / 2.5 1565 / 2.5 1805 / 2.6 1821 / 7.1 1410 / 4.5 1669 / 5.4SCR Inlet Gas Temp

Engine Speed / BMEP

 Exhaust gas temperature into the catalyst is much lower than the SG5 (leaner AFR and turbo impact)  TWC light

- off temperature may be a challenge and require enrichment (FE effects unknown)  SCR technology will start with copper zeolite which historically performs well at lower temperature 

### Engine Dyno DataGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 17 

# Lean Gasoline System Development

Collaboration

– Key Supplier Involvement

Calibration and combustion performance evaluation of lean gasoline combustion technology enablers

Fuel injector to enable multiple close

- spaced injection capability

Aftertreatment hardware formulations supporting passive and active ammonia systems integration 

## The program is partnering with the following suppliers in order to develop a common understanding of the integration challenges to implement lean gasoline systems in to productionGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information

18 

# Lean Gasoline System Development

Future Work

– Remainder of FY13 and Project

Calibrate
 1.4L LDB engine fuel economy enhancing features

Integrate  LDB engine
 12V Stop/Start
 Active Thermal Management system
 Passive/Active Ammonia SCR System (PAASS)

Optimize
 Lean boosted controls & calibration for drivability

Demo  Demonstrate fuel economy & T2B2 emissionsGM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information GM Powertrain Advanced Engineering This presentation does not contain any proprietary, confidential, or otherwise restricted information 19 

# Lean Gasoline System Development
Summary

– FY12 to FY13

Phase 2

– Complete  SG5 NA engine utilized in vehicle to develop engine and aftertreatment controls along with utilizing as a lean combustion emissions generator  Passive and Active aftertreatment systems have been combined to provide the optimal lean gasoline aftertreatment system that minimizes urea consumption under all lean

- stratified and stoichiometric

- homogeneous operating conditions

Phase 3 (the last one)

– In process, final system optimization  4 Lean Downsize Boost (LDB) engines have been designed, procured & built  LDB engine calibration has supported optimization of the BSFC performance  LDB engine, 12V Stop/Start, Active Thermal Management and Gen 4 PAASS aftertreatment systems are installed in a Malibu development vehicle  Expect to meet FE and Emissions target

Timeline Evaluation Milestone ( 1 ) Evaluation Milestone ( 2 )

12 / 23 / 11 Cold ftp & H FE > 13 %

- simulated Gen 2 A/T dyno results

– achieved

12 / 21 / 12 C & H FE > 20 %

- projected Emissions < 150 % w/PM

- achieved

FY 13 Goal C & H FE > 25 % Emissions T 2 B 2