Background

The experiments were conducted on a 6-cylinder, 6 L, naturally aspirated, water-

cooled, equipped with DPF, direct-injection HDDE of model year 1992 (Hino W06E).

The HDDE was tested under two loads, 25% and 75%, under steady cycle on a

dynamometer.

The test fuels included neat diesel (reference fuel), hydrogen-, methane- and natural-

gas mixed with diesel.

Aerosol sampling, dilution and thermal conditioning include:

a rotating disc thermo-dilutor (Matter Engineering Model MD19-2E)

a thermal conditioner (ThC, Matter Engineering Model ThC-1).

• The diluted exhaust samples were then measured at ~25 and 300ºC, with which

the former is referred to as "volatile" and the latter as "nonvolatile" particles.

a scanning mobility particle sizer and condensation particle counter (SMPS/CPC)

system (GRIMM Model 5.500).

Experimental

Results and Discussion

Emissions of volatile and nonvolatile nanoparticles from HDDE running on different gas-diesel mixture fuelsL.-H. Young1*, Chau-Wei Lai1, Hsi-Hsien Yang2, Lin-Chi Wang3, Jau-Huai Lu4, Wen-Jhy Lee5

1Department of Occupational Safety and Health, China Medical University, Taichung 40402, Taiwan. 2Department of Environmental Engineering and Management, Chaoyang University of Technology, Taichung 41349, Taiwan. 3Department of Civil Engineering and Geomatics,

Cheng Shiu University, Kaohsiung 83347, Taiwan. 4Department of Mechanical Engineering, National Chung Hsing University, Taichung 40254, Taiwan. 5Department of

Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan

*Corresponding author: lhy@mail.cmu.edu.tw

(2018) 22nd ETH Conference on Combustion Generated Nanoparticles

China Medical University, Taichung, Taiwan

Acknowledgements

June 18-21, 2018 @ ETH-Zurich, Switzerland

Conclusions

Engine emission

valve

MD19-2E control unitElectronic

signal

Diluted

Sample

Rotating disk diluter

Thermo denuder and

Control unit

DM

A

Auxiliary pump

CPC

Dynamometer

Hino W06E (6000 c.c.)

Gas feul tank

Air intake filter

PUMP

75%-Load25%-Load

Pure Diesel M100 H100

Em

issio

n fa

cto

r, E

F (

#/b

hp

-hr)

1010

1011

1012

1013

1014

1015

1016

(b) EF25C 75%-Load

97.2%93.0%

19.3%

w/o DPF

w/ DPF

Pure Diesel M100 H100

Em

issio

n f

acto

r, E

F (

#/b

hp

-hr)

1010

1011

1012

1013

1014

1015

1016

(b) EF300C 75%-Load

98.3%98.2%

99.7%

w/o DPF

w/ DPF

Particle Diameter, Dp (nm)

10 100

Num

be

r C

on

centr

atio

n

dN

/dlo

gD

p (

#/c

m3)

0

107

2x107

3x107

4x107

0

107

2x107

3x107

4x107

5x107

w/o DPF

w/ DPF (right axis)

H100 NT25C (75%-Load)

1x

68.4 nm

22.6 nm

1x

Particle Diameter, Dp (nm)

10 100

Num

ber

Concentr

ation

dN

/dlo

gD

p (

#/c

m3)

0

2x106

4x106

6x106

8x106

0

3x105

6x105

9x105

1x106

2x106

w/o DPF

w/ DPF (right axis)

Pure Diese NT25C (75%-Load)

62.2 nm

62.2 nm

The use of gas-diesel mixture fuels resulted in increases of both volatile and non-

volatile particles number emissions, compared to that from pure diesel fuel. In general,

hydrogen and biogases resulted in the highest EF.

The increase of engine load (mostly in rpm) resulted in decreases of both EF25C and

EF300C, but slight increases of particle mode diameters.

The particle number remained relatively stable before and after heating to 300ºC,

indicating little volatile materials on the nanoparticles, except H2.

Diesel engine exhaust contains hazardous gas pollutants and nanoparticles (<100 nm)

that have been linked to adverse health effects and environmental impact. Amongst,

diesel engine particles (DEPs) are a complex mixture of nonvolatile (or solid) and

semivolatile components. The emission characteristics of the DEP depend on engine

type, speed, load, fuel type, aftertreatment and sampling conditions.

Recently, the need and trend of energy conservation and pollution abatement have

given rise to the use of gas fuels (e.g., hydrogen, methane, natural gas) gas-diesel

mixture fuels in diesel engines. The pollutant characteristics of such dual-fuel system are

not well studied, especially for number-based nanoparticles.

With that in mind, this study aims to evaluate the effects of gas-diesel mixture fuels

and diesel particulate filter (DPF) on the emission characteristics (number/size

distribution) of volatile and nonvolatile nanoparticles in heavy-duty diesel engine

(HDDE) exhaust.

Items Contents Notations

Commercial diesel Neat diesel Pure Diesel

Hydrogen H2:100% H100

Methane CH4:100% M100

Biogas A CH4:90% + CO2:10%* M90C10

Biogas B CH4:70% + CO2:30%* M70C30

Results and Discussion

Fig. 1 Gas fuel system

Fig. 2 Sampling/analytical

system

Fig. 3 Emission factors of volatile (EF25C) and nonvolatile (EF300C) particle number

for HDDE running on different gas-diesel mixture fuels under 25% and 75% load.

The use of gas-diesel mixture fuels resulted in increases of both volatile and non-volatile

particles number emissions, compared to that from pure diesel fuel, but have negligible

effects on the size distribution. Such observations may be related to the replacement of

O2 by the fuel gas, decrease of A/F ratio, and hence more incomplete combustion or

unburned fuel, indicated by the increase of HC emissions.

The DPF is highly effective for the removal of nonvolatile nanoparticles, regardless of the

engine load and gas-diesel fuel type, but not necessarily for volatile nanoparticles.

The increase of HC emissions from the use of gas fuels (H2 and CH4) may also increase

the likeliness of new “volatile” particle formation downstream of the PDF.

The increase of engine load (mostly in rpm) resulted in decreases of both volatile and

non-volatile particles number emissions, but slight increases of particle mode diameters.

This may be attributable to the high particle number and thus stronger coagulation growth

under high load.

The nanoparticles emitted under the tested conditions contained little volatile materials

on the nanoparticles, except H2.

The above results highlight that the benefits of gas-diesel mixture fuels for aerosol mass

reductions are possibly accompanied by the increase of aerosol number emissions.

Fig. 4 Size distributions of volatile (N25C) and nonvolatile (N300C) particle number for

HDDE running on different gas-diesel mixture fuels under 25% and 75% load.

Fig. 5 Emission factors of volatile (EF25C) and nonvolatile (EF300C) particle number

with and without DPF under 25% and 75% load.

EF25C @ 75% Load EF300C @ 75% Load

Fig. 6 Size distributions of volatile (N25C) particle number

with and without DPF under 75% load.

This work was supported by Taiwan’s Ministry of Science and Technology under the contract number of

MOST 106-2111-M-039-001. Also, thanks to the conference sponsors for waiving the participation fees.

new “volatile” particle formation

new “volatile” particle formation