bs-6 washcoat technology durability simulation and obd-ii

BS-6 washcoat Technology

&

Durability Simulation and OBD-II approach

Two Wheeler

Dinesh K Gogia

Air Purification-Automotive

12th International Conference & Exhibition ECT – 2019

The Durability of exhaust after treatment for Two wheeler is

defined as 20K and 35 K for vehicle Class 1-2 and class 3

respectively

OBD-II for Two wheeler shall be implemented from April 2023

In AIS-137, on road /CD durability is defined in SRC and it’s

simulation on ED as SBC

Automotive catalyst are subjected to physical, chemical

and thermal aging mechanism with different intensity

This presentation covers, BS-6 washcoat Technology, aging

test set-up and results as per SBC for catalyst durability for

two wheelers

Catalyst Durability

Presented at ECMA's 12th International Conference & Exhibition-2019

Mileage Accumulation on Vehicle

(SRC)

Accelerated Engine-bench Aging

(SBC)

Real world aging of after treatment system It is different in terms of chemical interaction

and physical phenomenon

Catalyst deterioration due to thermal aging,

poisoning due to fuel and oil are more

realistic

Deterioration may not be adequately

accounted

Components responsible for after treatment

systems are tested simultaneously

Generally it is for catalytic converter

Higher cost and time Lower cost and time

If vehicle driven on road/test track, difficult

to control variability

Well controlled engine operation and good

repeatability

If tested on Chassis Dynamometer, long

term engagement of test setup

Shorter duration, multiple catalyst can be

aged simultaneously

Pros & Cons of Catalyst aging on vehicle and accelerated

aging on engine test bed


SRC-LeCV Distance accumulation Characteristics

SRC cycle

classification

WMTC

classification

Cycle-1 Class 1

Cycle-2 Class 2-1 / 2-2

Cycle-3 Class 3-1

Cycle-4 Class 3-2

LAP-1 LAP-2 LAP-3 LAP-4 LAP-5

6 km 6 km 6 km 6km 6 km

REF: AIS-137

Durability

Class 1, 2.1-2.2

20000 km

Class 3.1 & 3.2

35000 km


Time, s Engine Air/Fuel RatioSecondary

Air

01-40 s

Stoichiometric, A/F Engine Condition

to achieve a minimum catalyst

temperature of 800 °C

None

41-45 s “Rich” A/F ratio to achieve a

maximum catalyst temperature 890 °C

or 90 ° C higher to minimum controlled

temp

None

46-55 s 3 % O2

56-60 s

Stoichiometric, A/F Engine Condition

to achieve a minimum catalyst

temperature of 800 °C

3 % O2

Standard Bench Cycle (SBC)


Standard Bench Cycle (SBC)

0

1

2

3

4

0 10 20 30 40 50 60 70

Air

Inje

ctio

n ,

O2

%

Air

/Fu

el R

atio

Time,sAir/Fuel Ratio Air Injection

Stoichiometric

Control Catalyst Temperature

Time duration on SBC is calculated by Bench Aging Time (BAT) Eq. to equate

Desired kms. Run on SRC


Temperature Traces :

750

800

850

900

950

1000

2530 2650 2770 2890 3010 3130 3250 3370 3490

Tem

pe

ratu

re C

Time, s

Brick 1

Pre Cat 1 Post Cat 1 Brick 1

26th April 2018 Confidential

Bench Aging Time (BAT) Eq.

• BAT Eq. calculates the aging time

duration on engine dynamometer

for SBC to simulate equivalence to

SRC aging on CD

• BAT Eq. Requires -

Time vs Temperature data

measured at 1Hz at the hottest

point in the catalyst over SRC

The measured temperature data

shall be tabulated into a

histogram with temperature bins

For each temperature-bin the

equivalent ageing time (in

hours) is calculated as follows:

0

50

100

0 500 1000 1500 2000

Veh

icle

Sp

eed

, km

/h

Tem

per

atu

re °

K

Time,s

T_PRE_CAT K T_CAT_BRICK K

Vehicle Speed, km/h


0

50

100

150

200

Tim

e,h

rs

Mid Point Brick Temp ° K BIN

Bench Aging Time (BAT) Equation

𝒕𝒆 = 𝒕𝒉𝒆𝒙𝒑[𝑹𝟏

𝑻𝒓−

𝟏

𝑻𝒗]

BAT = A * 𝒕𝒆𝒕𝒆 : Equivalent aging time for each temp bin

𝒕𝒉 : Measured time in hrs with in temperature bin adjusted for full life

𝑻𝒓 : Effective Reference temp. (°K) for Catalyst design and on engine bench

𝑻𝒗 : Mid point Temperature (°K) of each temperature bin

A : 1.1 to factor other deterioration e.g. thermal, chemical poisoning etc

BAT : Bench Aging Time in hrs

R : 17500 Catalyst Thermal reactivityPresented at ECMA's 12th International Conference & Exhibition-2019

Engine Aging Set-up @ SCIL Vadodara

• Engine Specification;

• EngineCapacity : 1298 cc

• No of cylinder : 4 inline

• Bore & Stroke : 74 & 75.5 mm

• Compression Ratio : 9: 1

• Max Power : 87 bhp @ 6000rpm

• Max Torque : 113Nm @4500rpm

• Fuel Distribution : MPFI

• ECU : DENSOO 32 Bit


Modification in Aging setup for Two Wheeler Catalyst

Catalytic Converter size : Dia 40 * 60 or 74.5 mm Length

No of Catalyst to be aged simultaneously : 8 nos.


Hydrothermal Aging Set up

Gas Mass Flow Controller

Temperature Controller

Water Flow Controller

Gas / N2 /

Water Inlet

Maximum Oven Temp. : 1300 C

0

500

1000

1500

Te

mp

era

ture

C

Time, hrRoom Temp. C


OBD-II Strategy


Pollutant

BS-6

Norms

(DF)

V1

Limit

Typical % Conversion Efficiency

RequirementOBD –II Limit

WMTC 2.1 WMTC 2.2 WMTC 3.2

CO1000

(1.3)538 80 77 82 1900

NMHC68

(1.3)37 96 94 95 250

NOx60

(1.3)32 92 96 97 300

Durability km 20000 30000

Emission Norms and OBD-II Emission thresholds for BS-VI mg/km

Most Stringent Target : NMHC

BS-4 THC+NOx : 790 mg/km NOx : 390 mg/km


OBD

Monitoring Items OBD-Stage-I1

stApril 2020

OBD-Stage-II1

stApril 2023

Circuit continuity for all emission related powertrain

component (if equipped) √ √

Distance Travelled since MIL ON √ √

Electrical disconnection of Electronic Evaporative purge

control device ( if equipped & if active) √ √

Catalytic Converter Monitoring X √

EGR system Monitoring √ √

Misfire Detection X √

Oxygen Sensor Deterioration X √

OBD in automotive terms refers to a Vehicle’s self Diagnostic and reporting

capability. OBD for emission control detects the likely area of malfunction by

means of fault codes stored in the computer memory


OBD Simulation on Synthetic Gas Reactor of

by measuring OSC


• For OSC assessment on vehicle, procedure followed by some EMS

supplier is

– Deplete stored oxygen in catalyst at Rich A/F

– Leaning A/F

– Time delay in pre and post lambda sensor or amplitude corresponding

to threshold ME limit

• Same procedure is simulated on Synthetic gas for OBD calibration

• Procedure has been established to quantify OSC by using Broad

Band Lambda sensors

OSC Measurement and simulation on Synthetic Gas Reactor


OSC measurement on synthetic Gas Rig


• Temperature Setting 550 °C

• Cycle Timing 120 sec/120 sec R/L/R/L/R/L/R/L/R/…..

Duration: 4.5 cycles; 120sec settling time

l

Time

L

R

L

R

L

R

L

R R

Space Velocity (hr-1) per catalyst: 60k

Monolithic Catalysts

Post cat heated O2 sensorPre cat heated O2 sensor

Methodology for OSC Estimation

% age OSC of aged Catalyst

w.r.t Fresh

Pre Cat signal


FA

𝐎𝐒𝐂% =𝑨𝒓𝒆𝒂 𝒐𝒇 𝑨𝒈𝒆𝒅 𝑪𝒂𝒕𝒂𝒍𝒚𝒔𝒕 (𝑨)

𝑨𝒓𝒆𝒂 𝒐𝒇 𝑭𝒓𝒆𝒔𝒉 𝑪𝒂𝒕𝒂𝒍𝒚𝒔𝒕 (𝑭)∗ 𝟏𝟎𝟎

Post Cat Signal – Fresh

Post Cat Signal- Aged

Relationship between HC and OSC – Two wheeler

0102030405060708090

100

Fresh EE125T EE250T EE350T FE600T FE850T

HC

, mg/

km

Re

lati

ve O

SC %

Aging Severity >>>>>>

With increase in Aging severity, OSC drops, resulting

in increase in HC emission


Test Results on BS-VI washcoat Technology


Effect of WC on Light-off @ 0.97 lambda


0

100

200

300

CO-LOT HC-LOT NOx-LOT

LOT,

deg

C

60 g/cft WC-L 60 g/cft WC-M

All catalysts prepared with same PGM ratio

HC-LOT lowered with change of wash coat chemistry

HC-LOT vs WC’s @ 1.0 Lambda (GHSV 100,000 1/h)


0

50

100

150

200

250

860C2-60 910C2-60 901C2-60

HC

-LO

T &

%C

on

.

Wash Coat & PGM Loading

HC-LOT @ 1.0 lambda & %Con. @ 450 deg C

HC-LOT HC%

All pristine samples are loaded with the PGM of 60 g/cft

NMHC dilute emission comparison Gen-1 & Gen-2

0

20

40

60

80

100

0100200300400500600700

0 100 200

Veh

icle

Sp

eed

Km

ph

NM

HC

pp

m

Time (Sec)

0

50

100

150

Phase-1 Phase-2 Combined(30:70)

Mas

s Em

issi

on

, mg

/km

0

20

40

60

80

100

120

0

10

20

30

40

50

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

Veh

icle

Sp

eed

Km

ph

NM

HC

Cu

mu

lati

ve

mg

/km

Time (Sec)

THC __Gen_1 THC __Gen_2 Speed (Kmph)


CO dilute emission comparison Gen-1 & Gen-2

0

20

40

60

80

100

120

140

0

10

20

30

40

50

60

70

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

Veh

icle

Sp

eed

Km

ph

CO

cu

mm

ilati

ve m

g/k

m

Time (Sec)

CO __Gen_1 CO __Gen_2 Speed (Kmph)

0

20

40

60

80

100

0

100

200

300

400

500

600

0 100 200

Veh

icle

Sp

eed

Km

ph

CO

pp

m

Time (Sec)0

20

40

60

80

100

120

140

160

Phase-1 Phase-2 Combined (30:70)

Mas

s Em

issi

on

, mg/

km


NOx dilute emission comparison Gen-1 & Gen-2

0

20

40

60

80

100

120

140

0

2

4

6

8

10

12

14

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

Veh

icle

Sp

eed

Km

ph

NO

x C

um

mila

tive

m

g/k

m

Time (Sec)

NOX _Gen_1 NOX _Gen_2 Speed (Kmph)

0

20

40

60

80

100

0

20

40

60

80

100

0 100 200

Veh

icle

Sp

eed

, km

ph

No

x, p

pm

Time,s

0

5

1015

2025

30

35

Phase-1 Phase-2 Combined(30:70)

Mas

s em

issi

on

, mg

/km


Mass emission performance for Fresh and Aged Catalysts


0

10

20

30

40

50

60

CO/10 THC NMHC NOx

Mas

s em

issi

on

, mg

/km

BS-6 V-1 Limit Fresh Ageing-2 Ageing-3

BS-4 Catalyst aging comparison on Class 2.1 Motorcycle

ED Aging Condition

Mode Condition

BrickTemperature ,Degc

Time, Hr

Avg.Lambd

a

CO (% Vol)

O2(% Vol)

1 Stoichiometric 850-870 50 1.014 3.79 1

Road Aging HT Aging


0.0

0.5

1.0

1.5

2.0

Fresh HT Aged 900C/ 4h

50 Hrs EDAged

Aged_Veh@15000km

Emis

sio

n, g

/km

y = -1E-06x + 1.4319R² = 0.0135

y = 5E-06x + 0.2903R² = 0.641

y = 3E-06x + 0.1047R² = 0.8698

0

0.5

1

1.5

2

2.5

0 10000 20000 30000

Emis

sio

n, g

/km

Vehicle run, km

CO HC NOx

BS-6 Catalyst Durability of WMTC Class 2.2 Vehicle over SRC

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000

CO

/10

, HC

, No

x, N

MH

C

mg

/km

Kms over SRC

THC NOx NMHC CO/10Linear (THC) Linear (NOx) Linear (NMHC) Linear (CO/10)

BS-6 Limits: CO, HC NOx, NMHC


New Generation low LOT washcoat has met BS-VI engineering

Target including durability across various models with different

OEM

SCIL is equipped to perform accelerated catalyst aging on

Engine Dynamometer as per the procedure defined in AIS-137

for two wheeler

Developed methodology to measure OSC of catalyst on

Synthetic Gas reactor in a similar manner as followed on

vehicle for OBD-II simulation

Conclusions

SCIL is equipped to work closely with OEM’s on After

treatment system - complying to OBD-II


bs-6 washcoat technology durability simulation and obd-ii

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