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Definition of TWC Retrofit• Retrofit kit for retrospective aftermarket fitment to an in-use vehicle Background • Germany – Practical example of a national but voluntary retrofit scheme

Three Way Catalyst Retrofit

Robert Evans Johnson Matthey CSD

January, 31, 2001

Contents

• Definition

• Background

• Description of System

• Test Results

• Policy case study

• Conclusions

Definition of TWC Retrofit

• TWC = Three Way Catalyst

4HC + 5O2 2H2O + 4CO2

2CO + O2 2CO2

2CO +2NO N2 + 2CO2

}2-way}3-way

Oxidation

Reduction

{

HC

CO

NOx

CO2

H2O

N2

Three Way Emissions Control

0%

50%

100%

Definition of TWC Retrofit

• Retrofit kit for retrospective

(aftermarket) fitment to an in-use

vehicle

Background

• Germany

– Practical example of a national but

voluntary retrofit scheme

– Alternative to accelerated scrappage

• China

– Highly regulated scheme tackling

local air quality

Principle of the System

Load

Fuel:Air

Lean

Rich

Rejetting Carburettor pushes operation rich

of lambda = 1

1

Air valve pushes

in air to moderate the fuel:air to lambda =1

Test Results

0

0.5

1

1.5

2

2.5

3

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

(HC + NOx) [g/km]

Injection carburettor

EURO I emission standard

EURO II emission standard

Source: HJS

Retrofit Durability Trials

• Johnson Matthey tests

Retrofit system

– Ford Fiesta 1.0 litre engine

– ageing by road mileage accumulation

– fuel was pump-grade unleaded

gasoline

Test Results

0

1

2

3

4

5

6

91/441/EEC No catalyst Fresh Catalyst 5,000 miles 10,000 miles 15,000 miles

Source: Johnson Matthey

Real World Testing

Emissions Testing

Real World Testing

Driveability

Policy Case Study

• UK Cleaner Vehicles Task Force

– promote environmentally friendly

vehicles that people and businesses

will want to buy and use

– improve the environmental

performance of the existing vehicle

stock

Air Quality Objectives

• UK problems are with urban PM

– Even allowing for tighter emissions

legislation, air quality standards will

not be met

– Need an improvement in emissions

from the existing fleet

Transport NOx Sources

LGV 7%

Cars 54%

HGV 32%

Buses 7%

Most NOx from Pre-Euro 1 Cars

0

50

100

150

200

250

300

350

400

450

500

550

0 50 100 150 200 250 300 350 400 450 500 550

Sources: SMMT, AID

K tonnes NOx

UK Car Census

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84

0%

20%

40%

60%

80%

100%

500,000

1,000,000

1,500,000

2,000,000

2,500,000

99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 < 84

petrol diesel scrapped

Sources: SMMT, AID

Census by Emissions Control

Registrations

… or Scrappage

0

500,000

1,000,000

1,500,000

2,000,000

TWC Retrofit

Accelerated Scrappage

Registrations

Benefit-Cost Ratio

0

10

20

30

40

50

60

TWC Retrofit

Low cost High cost

CNG lean CNG stioc

Source: Cleaner Vehicles Task Force Technology & Testing Report 2000

NOx Reduction Options

• Accelerated scrappage

• Cut vehicle mileage (fuel tax)

• Stringent testing regimes

• TWC Retrofit

• Incentives for alternative fuels

Implementation Issues

• Regulatory regime

– Certification and in-service testing

• Willingness to pay

– Cost of technology and likely budget

• Scope of scheme

– Local or national, voluntary or

compulsory, incentive or tax

Conclusions

• TWC Retrofit is viable upgrade

option giving > 70% NOx reduction

• Is attractive (Benefit:cost)

compared with other policy options

• Can be implemented nationally or

locally