Off-road Small-engine
Emissions Measurement with theparSYNC® miniPEMS
August 10, 2020

https://3datx.com/

2

Four Test Articles, One Hour Testing Window
Riding LawnMower

Snow
BlowerPush LawnMower

PowerWasher

3Motivation
Off-road (or nonroad) emissions are increasingly larger contributor to total emissions for many key
pollutants, including NO and PM/PN. Also, there is a much larger uncertainty to modeling off-road
emissions due to:- Significantly larger variety of manufacturers, models, and sizes- Large variety of operations (compare to predominantly driving for onroad)- Usage patterns are not tracked (compare to VMT for onroad)- Maintenance records are non-existent; no I/M program- Hard to measure due to lack of space to install equipment- Overall, emissions modelers have to make many assumptions to fill vast data gaps
The first step to solving the off-road emissions puzzle is more widespread testing – more equipment
types at more locations across the country.
Our motivation for this exercise is to demonstrate that a miniPEMS is an excellent tool to tackle thechallenges of off-road emissions measurement and, as a consequence, provide valuable data to assist
with compliance and modeling efforts.

4Test Setup#TypeMakeEngine

Operation

1Riding Lawn Mower

John Deere D160

724 cc, 24 hp, 2cylinders

2Snow Blower

Craftsman

205 cc, Briggs andStraton, 4-cycle OHV

3Push Lawn Mower

Toro

190 cc, RWD, 1cylinder4Power Washer

Generac

173 cc, 4-cycle OHVWhile riding over grass, the cutting blade
was engaged/disengaged multiple times
Engine does the work in moving blower
forward, single speed maintained during
test
Operator pushes mower over the grass,the cutting blade is always engaged,
single speed maintained during test
Operator repeatedly pressed the trigger
to release pressurized water

All are gasoline fueled. OHV – over head valve; RWD – rear-wheel drive

Watch the test video (~2 min) at https://www.youtube.com/watch?v=EF__V5Ex8dY

5Using CO2 as surrogate for engine power
demandThe next four graphs show only the CO2 trace for each test article with description of operation
during the emissions measurement. Later, we compare the four test articles on a per pollutant basis
for NO, CO, PM, and PN.

6Riding Lawn Mower
700

12600

This axis will have the pollutant

Cold start

Each spike is cutting blade engage/disengage

10Engine off

500
400

CO2 does not drop drasticallywhen blade is disengaged

300

64200

Engine off

100
00100

200

Cold, or almost cold, start

300
Time (sec)

400

2500

600

0

CO2 (%)

8

7

Snow Blower
3.0E+06

12Engine off

2.5E+06

This axis will have the pollutant

Cold Start

10

CO2 stays consistently high8

1.5E+06

6Engine does work in propelling the equipment forward
Single speed throughout the test
Only time throttle is let go is when turning

1.0E+06

45.0E+05

20.0E+00

0050

100

150

200
Time (sec)

250

300

350

CO2 (%)

2.0E+06

8

Push Lawn Mower
700

12600

This axis will have the pollutant

10Engine off

Cold Start

500
400

6300
4200

Pushed by operator; cutting blade (auger) is always onSingle speed (no throttle, just on/off)Engine seemed to run rough in the middle
Smoke from makeshift exhaust pipe fitment (see pictures at end)

1000050100

150Time (sec)

200

250

2300

0

CO2 (%)

89Power Washer
700

12Each spike is trigger press to release pressurized waterThis axis will have the pollutant

600

Cold Start

10Engine off

500
400

6300

4200

Engine does work to pressurize and eject water
CO2 drops significantly when trigger is released

1000050100

150Time (sec)

200

2250

300

0

CO2 (%)

8

10

Comparison of Emissions
These graphs compare emissions, per pollutant for NO, CO, PM, and PN, between the test articles.
The right-side y-axis is always CO2. The y-axis scales are set to be same, for a given pollutant, acrosstest articles except for the particulate matter emissions for the snow blower (marked with ). We
also measured NO2 but it was at or below 10 ppm for all tests and the charts are included at the end.

11Nitric Oxide (NO) Emissions
10600

300
4200

100

200700300
Time (sec)

400

500

600

Push Lawn Mower

600

No cold start spike. Sensitive to transient loads.
Section in second half with low NO is when mower was idling

500

700

10600

30004050100150
Time (sec)

200

250

300

300

12610060

Cold start NO is moderate. Baseline NO is comparatively high.

42050100150200250300350

Time (sec)Power Washer

012High NO emissions when pressurizing water.
Q: How would this look for a long episode of pressurized water?

10500

8200

4000400

8100

CO2 (%)NO (ppm)

01020021000

CO2 (%)NO (ppm)

6Snow Blower

500

8400

128400
6300
4200

2100

00

CO2 (%)High NO peaks align with CO2. Baseline NO is much lower.
Q: How would this look when blade is engaged for long periods?

500

NO (ppm)

700

Riding Lawn Mower

600

NO (ppm)

122050100150
Time (sec)2002503000CO2 (%)

700

12Carbon Monoxide (CO) Emissions
Riding Lawn Mower

86434

Very high CO emissions. CO increases when CO2 decreases (and vice versa).
Sign of poor combustion control? Known feature of engine design?

20100

200

9300
Time (sec)

400

500

600

CO (%)

60

1296434

Moderately high CO at cold start (open loop?); much lower levels later.
Seems to have the best CO control in this group.

22100050100

150Time (sec)20025030004High CO peak at cold start. CO stays moderately high throughout.

0250100150200250300350

Time (sec)Power Washer

8Moderately high CO emissions correlated to work
106856434221001278564110752Push Lawn Mower

88321106

CO2 (%)
CO (%)

85

Snow Blower

7CO2 (%)
CO (%)

CO (%)

6128

1070

9CO2 (%)

12050100150
Time (sec)2002503000

CO2 (%)

913

Particulate Matter (PM) Mass Emissions
3.0E+06

102.5E+06

102.0E+04

82.0E+06

8

1.5E+04

61.0E+04

45.0E+03

25.0E+0500.0E+00

12

3.0E+04

2.5E+04

102.5E+04

102.0E+04

8

2.0E+048

1.5E+046

1.5E+046

1.0E+044

1.0E+0445.0E+03

25.0E+03

200.0E+00

0

PM (µg/m3)

3.0E+04

0.0E+00

100

200

300
Time (sec)

400

500

600

Push Lawn Mower

High PM emissions. Spike at end likely related to burn-off of tape.
050

1.5E+06100

150Time (sec)

200

250

300

6

Very high PM spike at cold start. PM emissions continue to becomparable to other test articles though the trace looks close to zero(because of scale).

1.0E+06

4See graph at end with y-axis set to same scale as other charts here.

050

Power Washer

CO2 (%)3PM (µg/m)

PM (µg/m3)

0.0E+00

Strong PM spikes at engine start. PM related to work load.

CO2 (%)3PM (µg/m)

Riding Lawn Mower
2.5E+04

12Snow Blower

050

100150200
Time (sec)

250

300

CO2 (%)

122350012Comparatively lower PM emissions overall

100150Time (sec)

200

250

300

0

CO2 (%)

3.0E+04

14Particle Number (PN) Emissions
2.5E+07122.5E+08

12Riding Lawn Mower

61.0E+07

4

5.0E+06

0.0E+00

1002002.5E+07300
Time (sec)

400

500

600

1.0E+08

5.0E+07208

1.5E+0800.0E+00

12

2.5E+07

0Push Lawn Mower

8

1.5E+076
1.0E+074

High PN emissions. Spike at end likely related to burn-off of tape.
2050

See graph at end with y-axis set to same scale as othercharts here.

250

100

150
Time (sec)

200

250

300

0100

150
200
Time (sec)

250

300

4350

012PN strongly related to work. PN spikes when CO2 drops. Why?

102.0E+07

CO2 (%) 3
PN (#/cm)

PN (#/cm3)

2.0E+07

0.0E+00

6Power Washer
105.0E+06

High PN spike at cold start. PN emissions continue to becomparable to other test articles though the trace looks
lower (because of scale). Dip in the middle is not explainedby the limited data.

8

1.5E+076
1.0E+07

45.0E+06

0.0E+00

CO2 (%)

8

1.5E+0710

2.0E+08

2050

100

150
Time (sec)

200

250

300

0

CO2 (%)

PN stays high after cold start (while the PM dropped)

CO2 (%) 3
PN (#/cm)PN (#/cm3)

2.0E+07

Snow Blower
1015Additional Pictures

Riding Lawn Mower

16

Snow Blower

17

Push Lawn Mower

18

Power Washer

19

20

Additional Graphs

Nitrogen Dioxide (NO2) Emissions
Riding Lawn Mower
Negligible NO2 emissions. Partly reported at -1 ppm, due to near zeroemissions and sensor precision.

856443
20100

200

10300
Time (sec)

400

500

600

Push Lawn Mower

981210644322

1050

100150Time (sec)200250300

0Negligible NO2 emissions. Partly reported at -2 ppm, due to nearzero emissions and sensor precision.

3042050

100200150250

300350Time (sec)Power Washer

9107865644322100
12Negligible NO2 emissions.

88564010651Negligible NO2 emissions.

786221NO2 (ppm)

78

6108

CO2 (%)
NO2 (ppm)

NO2 (ppm)

712Snow Blower

910

CO2 (%)
NO2 (ppm)

90

10

CO2 (%)

12050

100150Time (sec)

200

250

300

0

CO2 (%)

10021

22PM and PN Graphs for Snow Blower
122.5E+04

102.0E+0481.5E+04

6

1.0E+0445.0E+032

0.0E+00

050

100150200
Time (sec)

250

300

3500

2.5E+071210

2.0E+078

1.5E+076
1.0E+0745.0E+06

0.0E+00

2050

100

150200Time (sec)

250

300

3500

CO2 (%)

3.0E+04

CO2 (%) 3
PN (#/cm)

PM (µg/m3)

Y-axis set to lower value