AT and Emissions Control Keynote for publication · Future aftertreatment and emissions control technology should be • High efficiency over the widest range of feedgas properties

© Ricardo plc 2017

Aftertreatment and Emissions Control for Improved GHG and Air Quality

Mark Christie , Andy WardRicardo plc15 June 2017

215 June 2017For Wisconsin ERC Symposium © Ricardo plc 2017

• Introduction

• Light-duty applications

– Drivers and requirements

– Diesel technology

– Gasoline technology

• Heavy Duty



• Summary and Conclusions

Contents


Future Propulsion Systems

Propulsion systems must meet competing needs for a wide variety of applications. Aftertreatment and emissions control technology is key to meeting these needs for thermal propulsion syste ms

FUTUREPROPULSION

SYSTEMS

* WTW - Well to wheels

Future aftertreatment andemissions control technologyshould be• High efficiency over the

widest range of feedgasproperties

• Cost effective• Enable high powertrain

efficiency• Maintain performance over

product life


WHO estimates 7 million or ~1 in 8 global deaths linked to impacts of poor air quality

Air pollution now world’s largest single environmental health risk.


Air Quality – Why It Matters

Contribution of transport emissions to overall burd en of emissions

• NOx emissions in Europe are predominantly from the transport sector

• Not the case for some other pollutants where other sources dominate

Non-transport,

73%

Road transport exhaust, 10%

Road transport non-exhaust, 5%

Domestic shipping, 2%

International shipping, 10%

Transport, 27%

PM2.5

Non-transport,

42%

Road transport exhaust, 33%

Railways, 1%Domestic shipping, 4%


Domestic aviation, 1%International aviation,

4%

Transport, 58%

NOx

Non-transport,

79%

Domestic shipping, 2%


Transport, 21%

SOx


NOx emissions in cities and human exposure at roads ide are dominated by road transport

At the roadside transport emissions completely dominate human exposure

Legal Limit

Areas exceeding NO2 limit

• Close to roads, the contribution from road vehicles easily dominates concentrations and exposure – across the EU, road transport emissions account for 64% of NO2 concentrations

• Emissions are released at ground level where they have maximum impact



Evidence exists that roadside NO 2 has been falling, but levels are still higher than those permitted by Air Qualit y legislation

• Roadside NO2 falling but too slowly

• Not all NO2 derives from light-duty diesel vehicles, but they are seen as substantial contributors

• All diesel vehicles fitted with particulate traps since Euro 5 or earlier

– Diesel Pm emissions now lower than gasoline vehicles

Trends in raw and meteorology-adjusted NO2data – 15 London Roadside Sites

Annual mean limit value 40µg/m 3



• Introduction





• Heavy Duty




Contents


Passenger car & LCV legislation is led by Europe an d US, with other regions currently following Planned/Implemented

Predicted Unknown

Source: Ricardo EMLEG Emissions Legislation database www.emleg.com

2005 20152010 20302020 2025

Emissions Euro 4

EPA Tier 3

Post-Euro 6Euro 5a Euro 5b Euro 6b Euro6dTEMP Euro 6d

NEDC WLTP + RDE

EPA Tier 2

2005 2010 2015 2020 2025 2030

2012-2016 CO2 limits 2017-2025 CO2 limits

EPA Tier 4

US FTP 75, SFTP (US06 cycle, SC03 cycle), HWFET

CARB LEV III (Harmonised with EPA Tier 3)

US FTP 75, SFTP (US06 cycle, SC03 cycle), HWFET

CARB LEV II

LEV II standards (2009-2016) LEV III (consistent with EPA standards, 2017-2025)

130 g(CO2)/km target (LCV-2017: 175 g(CO 2)/km) 68 – 78 g(CO2)/km 95 g(CO2)/km(LCV: 147 g(CO 2)/km )

2017 target 2022 target

Phase 1 Phase 2 Phase 3 Phase 4 (LCV: new standard from 2018)

Phase 5

Bharat Stage III Bharat Stage IV Bharat Stage VI

Indian Drive Cycle (NEDC with max speed reduced t o 90 km/h)

WLTP + RDENEDC

Indian Drive Cycle + RDE

China III China 6a China 6bChina IV China 5

Overview: Light-Duty and LCV Markets

Test cycles

CO2 / CAFC

Emissions

Test cycles

CO2 / CAFC

Emissions

Test cycles

CO2 / CAFC

Emissions

Test cycles

CO2 / CAFC

Emissions

Test cycles

CO2 / CAFC

Emissions

Test cycles

CO2 / CAFC

2020 targets

New long term

10-15 mode+11 mode

China

India

Japan

California

US-Federal

EU

RDE effective Sept 17 –WLTP proposed introduction Sept 17

Post new long term standards WLTP based standards

JC08 test cycle (with 10-15 mode until Oct 2011) WLTP + on-road testing

2015 targets2005 targets (diesel) 2010 targets (gasoline)


• Introduction





• Heavy Duty




Contents


Diesel Passenger Car

Post Euro 6 2020 Diesel Passenger Car Solutions

• Objective: improve the efficiency of current diesel powertrains and after-treatment technologies for multiple passenger car classifications

−Emissions capability beyond Euro 6d limits under real driving conditions

• ReWArD collaborative program initiated multiple OEMs, research institutes and suppliers involved under Ricardo leadership

• The work reported here received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 636380

Legislation CO [g/km] HC + NO X [g/km] NO X [g/km] PM [g/km] Pn [#/km]

Euro 6 0.50 0.170 0.08 0.005 6.0x1011

ReWArD 0.25 0.085 0.04 0.0025 3.0x10 11

REWARD Project Targets: RDE cycles conformity factor = 1.5



Wide temperature and space velocity range of RDE cy cles limits effectiveness of current after-treatment / NO X control solutions

Low temperature during urban driving:• Limited opportunity for LNT deNOX,

PNA desorption or Adblue injection• Likely requirement for active exhaust

thermal management

High speed content of highway phase:• high temperature and space

velocities (>100 kh-1) limiting effectiveness of NOX control

systems

Urban Rural Highway



The Ricardo Integrated Model Based Development allo ws a system level approach to evaluate potential solutions

A-T = after-treatment

Note: includes fuel consumption penalty



A number of cycles have to be considered to capture the range of real world conditions

• Delivery and RUK City contain only urban content • RA1-140+ designed to be at the limit

• RS115 considered standard driving

• RTS95 is above the limit

Urban Rural Highway

Urban Rural Highway



RDE Simulation Results: A comparison of LNT based s ystems with LNT + aSCRF

Note: NOx CFs on basis of

0.04g/km target

NOX CF results for 1.6L C-Segment

over RS115

UU

RRHH

Urban phaseUrban phase

Highway phase

Rural phase

UU

RR

HH

UU

RR HH

LNT-only based systems cannot achieve RDE conformity due to wide temperature range – aSCR required to extend range of NOX control



RDE Simulation Results: Evaluation of aSCR based sys tems with exhaust thermal management

Note: NOx CFs on basis of 0.04g/km target

aSCRF NOX CF results for 1.6L C-Segment

Exhaust thermal management required during RDE urban phase and RUK Delivery for PNA

and DOC systems (management of SCRF NH3loading also beneficial)

LNT reduces low temperature NOX slip risk

and suffers lower CO2penalty (deNOX + ETM)

PNAs are suitable for fixed short cycles when

paired with HT NOXcontrol, long urban

cycles result in saturation and highly transient events risk

tailpipe NOX slip

LNT+aSCRF PNA+aSCRF DOC+aSCRF

LNT offers NOx control advantage over PNA or DOC due to improved low temperature conversion



RDE Simulation Results - Summary

Clear oncost-CO2 trade-off

Note: larger area is a more favourable results

Addition of LNT to active SCR offers best fuel consumption at higher cost



Cost Benefit Trade Off

CO2/oncost 1.6L C-Segment

over WLTC

CONCLUSION: LNT coupled with aSCRF offers the best emissions/cost/CO2improvement trade off


• Introduction





• Heavy Duty




Contents


Post Euro 6/Tier 3 Gasoline Passenger Car Solutions

Parallel paths of lean and stoichiometric now being combined with Miller Cycle

λ = 1

λ > 1

Ricardo HyBoost & Adept

� Aggressively downsize gasoline engine (50%)

Ricardo Volcano

� Stratified charge engine

� Up to 40% brake thermal efficiency

The ultimate solution will be a combination of both approaches with ‘deep’ powertrain integration

Currently in development2015�2020

Next generation engines2025�

Ricardo Research2019�

Ricardo Magma λ = 1

� Advanced valvetraintrue ‘Miller’ engine

Ricardo Magma λ > 1

� As stoichiometric but with Lean operation

Integrated Electrified Thermal

Propulsion Systems

Real World Driving NOx Perspective λ = 1• Detailed development

challenges for high power operation and low speed scavenging

Real World Driving NOx Perspective λ > 1• Significant challenges but

significant additional CO2opportunity

Gasoline Passenger Car



Comparison of Lean Combustion Strategies

Lean stratified

• Lean boosted direct injection– Lambda up to 1.5

– Conventional ignition system

• Stratified gasoline direct injection– Lambda up to 4

– Piezo-electronic injectors required

• Ultra-lean homogeneous (λ = 2)– Lambda up to 2

– Advanced ignition system

Moderate lean homogeneous Ultra-lean homogeneous

• High FC benefit

• Low engine-out NOx

• Low to medium FC benefit

• Low engine-out NOx

• High FC benefit

• Medium engine-out NOx

The challenge is emission control under lean condition


• Project targets for WLTP NOx = 0.04 g/km [~30% engineering margin]

• The RDE the emissions limit via conformity factor (CF) of 1.5

• Project NOx CF for the aggressive RDE cycle of 1.0 [~30% engineering margin]

• N2O emissions limits outside of Euro 6d for the US and China legislation

Euro 6d and RDE Simulation Results – Lean Gasoline A ftertreatment

LegislationCO

[g/km]THC (NMHC)

[g/km]NOx

[g/km] N2O *

Euro 6d (WLTP)

1.0 0.1 (0.068) 0.06US

EPA 201210 mg/mile

Euro6d (RDE) 1.5 0.15 (0.102) 0.09China 6

202020 – 30 mg/km

* Not part of Euro 6 legislation




Advanced NOx control is required for lean operation – LNT and SCR systems provide NOx conversion capability under lean conditions, TWC is still required for stoichiometric operation

Euro 6d and RDE Simulation Results – Potential After treatment Layouts



λ = 1Warm-up

λ = lean (1.2 – 4.1)Possible lean operation

λ = 1High temperature NO x control

rich

lean

Stoichiometric exhaust temperature

Homogeneous leanexhaust temperature

Stratified leanexhaust temperature

Engine speed/load� Lean operational area

Exhaust temperature profile� Lean operational area

Engine lambda

LNT & SCRtemperature

operatingwindow

Euro 6d and RDE Simulation Results – Lambda Operatin g Regimes



Lean/stoichiometric ratio targets tailpipe NOx and defines the achievable CO2 benefit for the lean combustion strategy with aftertreatment system

λ = 1Warm-up

λ = lean (1.2 – 4.1)Possible lean operation

λ = 1High temperature NO x control

rich

lean

Engine lambda

Engine-out NOx

Close-coupled TWLNT out NOx

u/f LNT - Tailpipe NOx

lean

rich

Euro 6d and RDE Simulation Results – Lean/Stoichiome tric Ratio


Lean / stoichiometric (L/S) ratio can increases when the lean aftertreatment system NOx conversion capability increases

Lean stratifiedTwin LNT systems

Lean stratifiedSCR systems

Ultra-lean homogeneous

Twin LNT system

Lean homogeneousTwin LNT systems

Lean homogeneousSCR systems

Lean stratifiedSingle LNT systems

Lean homogeneousSingle LNT systems

Stratified

Homogeneous


Euro 6d and RDE Simulation Results – Lean/Stoichiome tric Ratio


LEAN-S – Engine add-on costs €90 (piezo injectors)LEAN-H (λ = 2) – Engine add-on costs €150 (Advanced ignition system)aSCR w/o AdBlue consumption incl. to FC benefit

C-Segment Baseline TWC

Stratified

Homogeneous

Lean stratifiedSingle LNT systems

Lean stratifiedTwin LNT systems

Lean stratifiedSCR systems

Lean homogeneousTwin LNT systems

Lean homogeneousSCR systems

Lean homogeneousSingle LNT systems

Ultra-lean homogeneous

Twin LNT system

Euro 6d and RDE Simulation Results – Cost Benefit Su mmary



• LNT and SCR systems produce N2O depending on amount of converted NOx and catalyst temperatures

• US and China legislations are have tight N2O emissions

– US EPA: 10 mg/mile and China 6: 20 -30 mg/km

• Simulated N2O tailpipe results need further hardware and calibration optimization

• China 6 looks feasible, unclear as yet if US limits can be met

LNT N2O emissions SCR N2O emissionsLNT CO2 benefits SCR CO2 benefits

Stratified HomogeneousStratified Homogeneous

Stratified HomogeneousStratified Homogeneous

Euro 6d and RDE Simulation Results – GHG N 2O Emissions WIP



• Every system was able to meet Euro 6d NO x emissions limits , utilising the ability of these engines to switch to stoichiometric operation and rely on TWC operation when needed

• Lean-to-stoichiometric (L/S) time ratio , defines the fuel consumption benefit available

• Lean stratified operation has a fuel consumption benefit over moderate lean homogeneous operation, but the ultra-lean homogeneous concept has competitive fuel consumption with stratified combustion

• LNT-based aftertreatment systems offer the cost-effective approach

• Active SCR systems delivered marginally higher fuel consumption/CO 2 benefits compared to twin LNT, but also have significantly increased costs resulting in a reduced cost to benefit ratio

• LNT & SCR aftertreatment systems create N2O during NOx conversion; further hardware and calibration optimisation are required to reduce N2O emissions, but 20 mg/km limits appear to be feasible

Euro 6d and RDE Simulation Results – Summary



• Introduction





• Heavy Duty




Contents


Global Emissions and CO 2 legislation continue to be key drivers influencing the development of Commercial Vehicles

Emissions legislation for heavy duty vehiclesPlanned/Implemented Delayed

Predicted Unknown

Source: EMLEG, Ricardo analysis 2005 20152010 20302020 2025

Emissions

CO2 / FC

Emissions

CO2 / FC

Emissions

CO2 / FC

Emissions

CO2 / FC

EmissionsMajor cities

Nationwide

CO2 / FC

EmissionsMajor cities

Nationwide

CO2 / FC

China III Beijing VI

Phase 1

Euro V (2008)Euro IV (2005)

CO2 Monitoring

EPA 04 EPA 2007

GHG Phase 1

JP05 (2005) PLT (2009) Future regulation (2016)

PROCONVE P-5 (2006) P-7 (2012) P-8?

BS III (2005) BS IV (2010) BS VI

BS II BS IV BS VI

GHG Phase 2

CO2 Limits

P-6 (2009 – skipped)

CO2 Limits

Phase 2 Phase 3

China II

Euro VII

CO2 Phase 2

EPA 2010

China IV China V

China VChina IV (2013)China III (2008)

CO2 Limits

BS III (2007)

Euro VI (2013)

EPA 2010 Ultra-low NOx

China VI

CO2 Limits

BSV (2020 – skipped)

ULTRA LOW NOx Voluntary

Diesel Commercial Vehicle


• Introduction





• Heavy Duty




Contents


Ultra Low NOx (ULN) – Focus Areas and Potential Solu tions

There Are Several Key Attention Areas And

Enablers To Help Reduce NOx



ULN Simulation Results – Concept Down SelectDiesel Commercial Vehicle

NOX

EMISSIONS RISK (non

NOX)

FUEL PENALTY

N2O

ROBUST/ DURAB

COST

FUTURE PROOF

LNT cDPF SCR

LNT SCRF SCR

PNA cDPF SCR

PNA SCRF SCR

SCR cDPF

SCRF SCR

AdvancedAdvancedAdvancedAdvanced High Potential

LayoutsLayoutsLayoutsLayouts For Detailed

Simulation Efforts

AdvancedAdvancedAdvancedAdvanced TechnologiesTechnologiesTechnologiesTechnologies

For Detailed Simulation

Efforts



Effect of Advanced Technologies on Base AT Layout: Composite Tailpipe NOx

NonNonNonNon---- Fuel PenaltyFuel PenaltyFuel PenaltyFuel Penalty

• Short mixer

• Gaseous ammonia

• Larger SCR

Fuel PenaltyFuel PenaltyFuel PenaltyFuel Penalty

• Close coupled EHC

• Smart EHC control and

optimized dosing control

Targeting ≈ 1-1.3 g/bhp-h

on HOT FTP

• X-Axis: NOx conversion during Cold FTP

• Y-Axis: NOx conversion during Hot FTP

• Z-Axis: Composite Cold-Hot FTP Tailpipe NOx in mg/bhp-h (1/7th Cold, 6/7th

Hot)



Advanced After-treatment Configurations with and wi thout Fuel Penalty: Composite Tailpipe NOx

TAKEAWAYSTAKEAWAYSTAKEAWAYSTAKEAWAYS

• Basic Advanced AT layouts have the potential to meet

optional NOx levels of 100 and 50mg without fuel penalty

• With fuel penalty, the advanced layouts have the

potential to meet 20mg with development margin.

• X-Axis: NOx conversion during Cold FTP

• Y-Axis: NOx conversion during Hot FTP

• Z-Axis: Composite Cold-Hot FTP Tailpipe NOx in mg/bhp-h (1/7th Cold, 6/7th

Hot)



Advanced After-treatment Configurations with and wi thout Fuel Penalty: Fuel Penalty

Base Layout with new Technology [no Fuel penalty]

Base Layout

Base with new Technology [Fuel Penalty ]

Advanced Layout

Advanced Layout with new Technology [no Fuel penalty]

Advanced Layout with new Technology [Fuel penalty]

0

20

40

60

80

100

120

140

160

180

200

220

240

-1 0 1 2 3 4 5 6 7 8

CO

MP

OS

ITE

FT

P [

mg/

bhp-

h]

COMPOSITE FUEL PENALTY[%]

TAKEAWAYSTAKEAWAYSTAKEAWAYSTAKEAWAYS

• Advanced technology layouts have the potential to

provide a development margin below 20mg as well

as reduce the fuel penalty


Target TPO NOx [mg/bhp-h]

Actual TPO NOx [mg/bhp-h]

Target Fuel Penalty [%]

Fuel Penalty [%]

N2O [mg/bhp-h]

Baseline 200 159 0 0 10

Soln. A 12 12 < 3 4.2 94

Soln. B 12 11 < 3 1.7 42


Final Layouts: Based on the simulation results and analysis, following two concepts are recommended

SOLUTION B:Cheap, Simple, High Risk

((((optional or virtual sensor using storage model ))))

PNAPNAPNAPNA

SC

RS

CR

SC

RS

CR

NONONONOxxxx

Urea InjectorUrea InjectorUrea InjectorUrea Injector

Urea mixerUrea mixerUrea mixerUrea mixer

SCRFSCRFSCRFSCRF

TTTTTTTT

AS

CA

SC

AS

CA

SC

NHNHNHNH3333

NONONONOxxxx

EH

CE

HC

EH

CE

HC

HC DoserHC DoserHC DoserHC Doser NONONONOxxxx

TTTT

∆∆∆∆P

NHNHNHNH3333

((((optional or virtual sensor dosing volume and

NOx sensor reading))))NONONONOxxxx

Urea InjectorUrea InjectorUrea InjectorUrea Injector NONONONOxxxx

EH

CE

HC

EH

CE

HC

SC

RS

CR

SC

RS

CR

NHNHNHNH3333

cDPFcDPFcDPFcDPF

TTTT

TURBOTURBOTURBOTURBO

HC DoserHC DoserHC DoserHC Doser

TTTT

∆∆∆∆P

SOLUTION A:Low risk, Complex


• Introduction





• Heavy Duty




Contents


• Aftertreatment systems continue to evolve to support the reduction of GHG and emissions that support high efficiency powertrain yet operate effectively over a wide range of feed gas conditions

• Predictive methods, capable of simulating RDE scenarios are key in developing compliant systems whilst simultaneously understanding CO2 trade-offs

• Light Duty Diesel aftertreatment configurations have been identified that can meet future conformation factors of 1.5.

• Lean gasoline aftertreatment systems show good potential to meet constituent emissions and initial work has suggests N2O emissions can be reduced to meet China 6 standards however more work is required before conclusions can be drawn for US standards

• The heavy duty on highway market faces 90% reduction in NOx emissions, work to date suggest that this can be met with advanced configurations but not without a CO2penalty

Summary and Conclusions

Documents

AT and Emissions Control Keynote for publication · Future aftertreatment and emissions control technology should be • High efficiency over the widest range of feedgas properties