Xác định các thành phần của khí thải từ động cơ ô tô sử dụng động cơ diesel LPG nhiên liệu kép

MINISTRY OF EDUCATION AND TRAINING
UNIVERSITY OF TRANSPORT AND COMMUNICATIONS

VUONG VAN SON

IDENTIFICATION OF COMPONENTS OF EXHAUST
FROM AUTOMOBILE ENGINES USING
DIESEL – LPG DUAL FUEL
Major: Automobiles and Tractors Engineering
Code: 62.52.35.01

SUMMARY OF THESIS FOR DOCTOR OF ENGINEERING

HA NOI - 2014


This thesis is completed at
UNIVERSITY OF TRANSPORT AND COMMUNICATIONS

Scientific Advisers:
1. Ass.Prof.Dr. Cao Trong Hien
2. Ass.Prof.Dr. Dao Manh Hung

Opponent 1:
Prof.Dr Pham Van Lang
Opponent 2:
Ass.Prof.Dr Lai Van Dinh
Opponent 3:
Ass.Prof.Dr Tran Van Nam

This thesis will be defended at Universitarian dissertation Committee

at University of Transport and Communications.
At …hour….date…month…year.

The thesis can be found at:
National Library
Library of University of Transport and Communications


1

INTRODUCTION
1. Background of the study
Exhaust emission from automobiles using diesel fuel is one of the
factors causing air pollution, particularly in urban areas. Among the
research plans to reduce the emission of toxic substances from the diesel
engine, many scientists are interested in the use of diesel - LPG dual fuel
engine. A lot of developed countries in the world have put finance and
efforts into this research.
When this method is applied, it will help to solve the two following
problems: protecting air environment and taking advantage of available fuel
resources in many parts of the world while fossil fuels are gradually running
out.
In Vietnam, LPG application for internal combustion engines has
been interested in many studies, but not really in-depth. The research results
only stopped at using LPG fuel for the engine but not interested in
optimizing fuel supplying system, combustion and pollutant formation yet.
With that situation, calculating and identifying components of exhaust
from automobile engines using diesel - LPG dual fuel becomes imperative
and incredibly practical.
2. Purposes of the study

- To identify the content of emission components when the LPG
supply system is fitted into diesel engine.
- To assess the effect of reducing emissions of diesel - LPG dual fuel
engine.
3. Subjects and scope of the study
* The subject of the study: This thesis focuses on engines using diesel
- LPG dual fuel mounted on small and medium -sized automobiles.
* The scope of the study: This thesis studies the exhaust emission of
the selected object on the basis of remaining all the specifications (torque
capacity) of the original diesel engine.
4. Methods of the study
This study combines theoretical research with empirical research
* In theory: Using theory of heat exchange and mass exchange of
internal combustion engines, using AVL - BOOST software to simulate the
engine working process and calculate the content of emissions.
* In empiric: The experiment was carried on the modern test tape
according to ECE cycle of Vietnam Register Department to determine the
amount of harmful exhaust, and base on the result to adjust the theoretical


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calculation results.
5. The scientific and practical meanings
* Scientific meaning: The thesis developed simulation models to
evaluate the emissions of diesel – LPG dual fuel engine. The calculation
results were compared and verified by experiment on the system of modern
testing equipment with international standards.
* Practical meaning: The results of the thesis are the basis for
evaluating environmental performance and engine power when using diesel

– LPG dual fuel.
Chapter I. OVERVIEW OF RESEARCH PROBLEMS
1.1. Overview of environmental pollution caused by automobiles’
emissions
1.1.1. The development of transportation in Vietnam
In recent years, along with economic growth, the demand for
transportation of people and goods in Vietnam has increased rapidly. This
has led to the increase of number of transport vehicles, especially ones
using diesel fuel . The increasing number of vehicles while the
transportation infrastructure has not developed causes pressure on the
environment, especially in urban areas.
1.1.2. Environmental pollution caused by automobiles’ emissions in
Vietnam
The increasing numbers of Transportation vehicles in undeveloped
infrastructure causes traffic jams in big cities. Meanwhile we do not have
any effective controlling measures to reduce emissions leading to the
alarming rate of air pollution in big cities, especially in Hanoi and Ho Chi
Minh City .
1.2. Production and utilization of LPG
1.2.1. Production of LPG
1.2.1.1. Production of LPG in the world
The total supply of LPG in the world reached 198 million tons in
2000 and 239 million tons in 2008. The growth rate of the LPG supply in
the world increased 2.4 % / year in 2000-2008. In 2013, the world supply
could reach 260 million tons and is expected to reach 291.7 million tons in
2015.
1.2.1.1. Production of LPG in Vietnam
Vietnam has about 3,000 billion m3 of gas concentrated mainly in our
continental shelf . In 2009, Dinh Co gas processing factory began producing

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LPG (about 29,000 tons / month) serving for industrial and consumer
products. From the second quarter of 2009, the Dung Quat oil filtration
factory has officially gone into operation and produced LPG to meet the
needs of LPG in the whole country.
1.2.2. The utilization of LPG
In the world: The use of LPG in the world focuses on four fields:
domestic consumption accounts for nearly 50 % , followed by the chemicals
field with 24 % , the use of LPG in industry is at the third rank with total
consumption accounting for about 13 % , while transport only ranks the
fourth with a total annual consumption of 8.8 % .
In Vietnam: Demand for LPG in Vietnam in recent years has
increased very quickly. In 2015, the demand for LPG is expected to be
about 1.5 million tons and 2 million tons by 2020. However, in our country,
LPG is mainly used as fuel; the use of LPG for transportation means is not
popular.
1.3. Domestic and foreign studies on emissions of diesel engines and
diesel – LPG engines
1.3.1. The research results in the world
In the world, there have been many studies in this field , as typical :
Works of BEROUN and MARTINS , Z.H Zhang , C.S. Cheung , T.L. Chan
and C.D. Yao , Bogdan Cornel BENEA and Adrian Ovidiu SOICA , Dong
Jian , Gao Xiaohong , Li Gesheng and Zhang Xintang , Thomas Renald
C.Ja and Somasundaram P , MP Poonia. However, those studies focused
mainly on engines mounted on passenger cars, large trucks and specialized
vehicles. The number of researches using diesel - LPG engines fitted on
small cars is very limited.
1.3.2. The research results in the country

In Vietnam, there have been some studies on the engines using diesel
- LPG dual fuel such as the studies of Bui Van Ga , Pham Minh Tuan , Le
Anh Tuan , Pham Huu Tuyen , Mai Son Hai , Tran Thanh Hai Tung , Le
Minh Xuan and Vu An. The initial results showed that automobiles using
diesel – LPG dual fuel helpes to reduce the harmful emissions, especially its
ability to reduce PM emissions on some engines. However, there have not
been any completed studies of diesel - LPG engine fitted on small cars.
1.4. Conclusion of Chapter I
Among many research plans to reduce the emission of toxic
substances from the diesel engine, the scientiests are very interested in the
use of diesel - LPG dual fuel engine . Many developed countries in the
world have put their finance and efforts into this research.


4

In Vietnam LPG applications for internal combustion engines has
been interested in many studies, but not really in-depth. The research results
only stopped at using LPG fuel for the engine but not interested in
optimizing fuel supplying system, combustion and pollutant formation yet.
Chapter II. THEORETICAL BASIS OF CALCUALTING
COMPONENTS OF EXHAUST EMISSION FROM DIESEL AND
DIESEL – LPG ENGINES
2.1. Mixture of diesel – LPG dual fuel
Based on the advantages and disadvantages of these methods and to
meet the research objectives, the study chose to inject the LPG into
charging pipe to survey and empiric. The diagram of LPG supply system
into diesel engine is presented in Figure 2.4.
2
3

1

4

5

7
9
6

10

8
12
13

14
11

15

16

Figure 2.4. Diagram of LPG supply system and turbochargers diesel fuel system
1. Air filters; 2. Charging air coolers; 3. Exhaust pipe 4. High pressure pump 5.
Coarse filters; 6. Turbochargers; 7. Nozzle; 8 . The pipeline takes the pressure
loading; 9 . Vaporized LPG Pipeline; 10 . Fuel pump; 11 . LPG flow control
valve; 12 . Crystal filters; 13 . LPG cylinders; 14 . LPG Pipeline; 15 Engine
cooler; 16. Diesel fuel tank; 17. Vaporized depression .

5

Speed of calorific (J/CA)

Speed of calorific (J/CA)

2.2. Theoretical basic of diesel engine and diesel – LPG engine
2.2.1. Combustion process in diesel engines
Combustion process in diesel engines can be divided into 4 phases:
Late Fire, rapid fire, main fire ( slow fire ) and dropped fire .
2.2.2. Combustion process in diesel – LPG dual fuel engines
Combustion process in diesel – LPG dual fuel engines is rather
complicated because of the combination of combustion in gasoline engines
and diesel engines. Besides late fire and dropped fire as the diesel fuel
engine, the combustion process can be divided into 3 main phases.
- Phase 1: The rapid fire with diesel fuel and a small portion of fuel gas.
- Phase 2: The rapid fire with most of LPG fuel and a portion of diesel fuel.
- Phase 3: The diffusion fire of diesel and remaining gas.
275

100 % diesel

2

225
175
125
75

25

5

1

-25

4

275
225
175

2

75, 9 diesel + 24, 1 %

125
75
25
-25
340

1

3

360

5
380

400

420

Crank’s angle of rotation(Degree)

Figure 2.8. Calorific process in diesel – LPG engine

2.2.3. Modeling basic of producing the mix and combustion in Diesel LPG dual fuel engine
Modeling basic of producing the mix and combustion are based on the
following rules:


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- The first thermodynamics equation
- Solvent mixture model is described by the components forming the
mixture including diesel fuel, LPG (C3H8, C4H10), O2, N2, CO2, H2O, CO, and
H2
- Heat transfer model is calculated according to the Woschni formula
1978.
- Use Vibe 2 zone fire model, the reactions of Zeldovich chain with
speed coefficient to calculate the amount of NOx, the reactions according to
A. Onorati to calculate CO, Hiroyasu model to calculate soot emissions in
the exhaust of diesel engines and diesel- LPG engines.
2.3. The exhaust components
Toxic products of combustion in diesel engines and diesel - LPG

engines included the following materials: HC, NOx, SO2, and dust particles
(PM).
2.4. Calculation base of emission component in diesel engines and diesel
– LPG engines
2.4.1. Calculating the NOx emission
The formation of NOx is calculated based on parameters such as
engine speed, fuel components, pressure, temperature, air intake coefficient
λ, volume and mass, burning time as well as areas of burning.
2.4.2. Calculating the CO emission
CO is combustion product lack of O2, mainly produced from the
incompleted combustion. Therefore, CO can be calculated based on the
responses according to A. Onorati:
CO + OH ↔ CO2 + H;
CO2 + O ↔ CO + O2.
2.4.3. Calculating the HC emission
For diesel engines, HC component generated in the process of
working is negligible, so most of the research on exhaust of diesel engine
has not mentioned the calculation of this component.
2.4.4. Calculating the soot emission (Soot)
Soot emission is calculated according Hiroyasu model. In this model ,
the change of the soot volume is calculatedvia the formula:
dms dms,f dms,ox


dt
dt
dt

(2.36)

2.5. Conclusion of Chapter II
In the plans of using of diesel – LPG dual fuel engine, the plan to


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inject LPG into charging pipe of the original diesel engine was selected as
the research plan. This plan has several advantages such as compact
structure, simple installation, no improvement to the original diesel engine.
The study used Vibe 2 zone fire model, the reactions of Zeldovich
chain with speed coefficient to calculate the amount of NOx, the reactions
according to A. Onorati to calculate CO, Hiroyasu model to calculate
emissions of soot in the exhaust of diesel engines and diesel- LPG engines.
Chapter III. DEVELOPING MODEL TO IDENTIFYING
COMPONENTS OF EXHAUST FROM DIESEL ENGINE AND
DIESEL – LPG ENGINE
3.1. AVL BOOST software
Based on the objectives and content of the study, the researcher chose
to calculate the emission of diesel engine by the simulation software. With
the available features and tools, AVL - BOOST can develop the model and
calculate the exhaust components of the engine.
3.2. Application of AVL - BOOST software in calculating exhaust
components of the FAWDE - 4DX23 engine
3.2.1. The basic parameters of FAWDE - 4DX23 engine
FAWDE - 4DX23 - 110 engine is the turbocharged diesel engine
made in China. This engine is used on passenger cars and small and
medium trucks. Rated power at 2800 rev / min is 81 KW, max torque at
1800 rev / min is 320 Nm.
3.2.2. Diesel fuel and LPG fuel
3.2.2.1. Diesel fuel

The main chemical composition of diesel fuel are hydrocarbon
compounds, general formula is CnH2n+2.
3.2.2.2. Liquefied petroleum gas (LPG)
The chemical composition of LPG is mainly paraffinic hydrocarbon
types, general formula is: CnH2n+2 such as : Propane (C3H8), Butane (C4H10),
Pentane (C5H12)… In addition, in LPG there are Ethane (C2H6), Ethylen
(C2H4), Butadiene (C4H4) but they account for a very small percentage.
3.2.3. Developing the diesel model on AVL - BOOST
Based on the structure of motor in fact, the elements defined in AVL BOOST and the specifications of the engine, FAWDE 4DX23 - 110 engine model can be built as in Figure 3.2. The function name of the
elements on the simulation model are presented in Table 3.4 .


8

Figure 3.2 The simulation model of FAWDE- 4DX23-110 engine on AVL-BOOST

After developing the model, the input data was entered basing on the
specifications of the engine, then run the program and export the results.
3.2.4. Verifying the accuracy of the model
The accuracy of the model was assessed by comparing the results
such as power, torque between the experimental results (the manufacturer
has tested and recorded in catalog before taking out the factory) with
simulation results. The simulation results showed that the highest deviation
range of the engine capacity was 6.48 % at the speed 1400 vg/ph and the
lowest is 1.13 %, this deviation range is acceptable.
3.2.5. Developing diesel - LPG engine model on AVL - BOOST.
The basic difference between combustion model in diesel – LPG
engine and diesel engine is the fuel component for the cycle. However,
various factors such as late combustion characteristics, heat exchange
coefficient , combustion speed ... when replacing LPG into diesel fuel has

been defined by the definition the nature of the fuel using (although the
general formula for the calculation is the same). Besides the basic
parameters such as low calorific value, A / F ratio, fuel is defined through
the thermodynamic parameters (heat capacity, enthalpy, entropy ...) for the
process of calculating and conversion chemical energy into calorific energy.
The developed model will be verified experimentally (it will be conducted
in the next part of this study). If simulation results are much different from
empirical results, it can be adjusted the parameter a, m of Vibe 2 zone fire
model when building the model.
To build the diesel – LPG engine model on AVL - BOOST, it must be


9

based on the layout of LPG supply system into diesel engine and the way to
mix them. According to the selected plan, LPG will be injected into the
engine's charging pipe. Thus on the model of diesel – LPG engine , apart
from the basic elements such as original diesel engine model will have more
injector ( I1 ) to simulate the process of providing LPG .

I1

Figure 3.5. Simulation model of diesel - LPG engine on AVL-BOOST

In the declaration on the input parameters for the model, in Classic
Specles Setup Section, after selecting fuel for diesel engine, it is necessary
to declare the chemical compositions of LPG, rate of Propane and Butane.
3.2.6. Computational simulation results
The simulation results of exhaust components of diesel engine and
diesel - LPG engine when running under ECE R49 cycle are showed in the

figure (3.7), (3.8), (3.9) and Table 3.8.
The simulation results in Figure 3.7 above shows that , when running
according to ECE R49 test cycle ,there is an increase of CO , the average
increase in LPG mode replaced 10 % of diesel by 77.42 % and in LPG
mode replace 20 % diesel by 151.8 % compared with using 100 % diesel .


10

Diesel
LPG_10
LPG_20

Figure 3.7. CO emission in the simulation modes according to ECE R49 cycle

Diesel
LPG_10
LPG_20

Figure 3.8. NOx emission in the simulation modes according to ECE R49 cycle

The simulation results in Figure 3.8 above shows that the
concentration of NOx in diesel- LPG engine decreased, In the LPG mode
replacing 10 % diesel, the average reduction is 3,427 % and the LPG mode
replacing 20 % diesel, the average reduction is 6,178 % comparing with 100
% diesel .
For soot emission, the result shows that when using dual fuel, soot
level fell average 16.76 % in the LPG mode replacing 10 % diesel and the
average reduction is 25.4 % in the LPG mode replacing 20 % diesel.

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Diesel
LPG_10
LPG_20

Figure 3.9. Soot emission in the simulation modes according to ECE R49 cycle
Table 3.8. Average emission according to ECE R49 cycle
Comparing
Comparing
Diesel_20
(%)
(%)

Component

Unit

Diesel

Diesel_10

CO

g/kW.h

1,469

2,606

77,42

3,699

151,8

NOX

g/kW.h

5,654

5,460

-3,427

5,305

-6,178

Soot

g/kW.h

0,299

0,249

-16,76

0,223

-25,40

3.3. Surveying the effect of some structural parameters on the emission
of diesel- LPG engine by simulation method
3.3.1. Effect of early spray on the emission of diesel- LPG engine
Based on engine model built, the study changed the time for spraying
diesel and considering its effect on the emission components in the LPG
mode replacing 20 % of diesel with 100 % loading of the engine is 1800 rev
/ min. According to the original engine, the timing of the fuel injection of
nozzle will be early 90, and stared at 3510 at crankshaft rotation .To change
this value into two directions, increasing and decreasing spraying angles
and investigating its effect to the engine's emission .
Emission result on Figure 3.10 and 3.11 shows that, while reducing
early, the NOx reduced, CO and soot increased. This phenomenon is due to
the time of most intense burning fuel in the engine cylinder is pushed
backward , while the piston has gone down over the course of expansion ,
the volume of the combustion chamber
increased leading to the
temperature and the pressure decreased effecting on the emission


12

components.

347

348

349

350

351

352 353

354

355

Figure 3.10. NOx and CO emissions at 100% loading, engine
speed 1800 rev / min according to early spraying angle

1800 v/ph

347

348

349

350

351

352

353

354

355

Figure 3.11. Soot emission at 100% loading with
engine speeds according to early spraying angle

3.3.2. The effect of gas distribution phase to the emission of diesel – LPG
engine
To survey the influence of gas distribution phase to the emission of the
engine, changing simultaneously the value of opening angle of loading
value and exhaust valve towards increasing early opening angle and late
closing angle. The exhaust gas composition will change as shown in Table
3.9.
Table 3.9 . The simulation results of emission components of diesel- LPG
engine according to ECE R49 cycle when changing air distribution angle


13

Decreasing Comparing Increasing Comparing
4º
%
4º
%

Component

Unit

Original

CO

g/kW.h

3,699

3,569

-3,515

4,313

16,61

NOx

g/kW.h

5,305

5,246

-1,102

5,481

3,333

Soot

g/kW.h

0,223

0,224

0,191

0,228

2,087

The above results show that early spray angle can be decreased to
reduce CO and NOx emission , however, there should have more
experimental research to find the best solutions to effectively reduce
emission of toxic .
3.4 . Conclusion of Chapter III
Application of AVL BOOST software to caculate
emission
components properties of FAWDE - 4DX23 - 110 engine fitted with LPG
injection system shows that :
- The amount of NOx reduced , the reduction in LPG mode replacing
10 % diesel is 3,427 % and in LPG mode replacing 20 % diesel is 6,178 %
compared with using 100 % diesel .
- The amount of CO in diesel - LPG engine increased, the increasing

in LPG mode replacing 10 % diesel is 77,42% and in LPG mode replacing
20 % diesel is 151,8% compared with using 100 % diesel .
- Soot emission while using dual fuel reduced, the reduction in LPG
mode replacing 10 % diesel is 16,76% and in LPG mode replacing 20 %
diesel is 25,4% compared with using 100 % diesel .
The thesis examined the influence of some structural parameters on
the emission of diesel engine when using diesel - LPG dual fuel. The results
show that, early spray angle can be adjusted to reduce CO and NOx
emissions, however , there should have more experimental research to find
more solutions so that grain dust emission do not exceed the limitation .
Chapter IV. EXPERIMENT AND EVALUATION
4.1 . The purpose and content of experiment
4.1.1 . The objective of experiment
- Accurately measure the exhaust components of the original diesel
engine and the diesel engine after being converted to use diesel – LPG dual
fuel.
- Evaluate the emission effectiveness of diesel engine when using
diesel - LPG dual fuel.
- Evaluate the accuracy of the theoretical calculation method based on


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experimental results .
4.1.2 . The content of experiment
- Determine the toxic emission of original diesel engine according to
ECE R49 cycle .
- Determine the toxic emission of diesel - LPG engine according to
ECE R49 cycle .
- Measure parameters to serve assessing the performance

characteristics of the engine such as power, torque , the engine's smoke ...
4.2 . Experimental Equipment
The contents of the experiment were conducted on a ETC01 high
dynamic test tape in the laboratory of engine emission under NETCVietnam Registry Department.
4.2.1 . Diagram of experimental equipment
Diagram of the experimental equipement is shown in Figure 4.2 .
The basic components of experimental equipement including :
- Power Brakes APA 404/6 PA
- Water Cooling Device AVL 553
- Oil Cooling Device AVL 554
- Rub out Controller THA 100
- Fuel consumption Measuring AVL Fuel Mas Flow Meter
- Gas Emission measurement system
- Particulate Sampler System - PSS i60)
- Smoke Measuring Device AVL 439 ( Equipped available in the lab )
4.3 . Selection and installation of LPG supply system into experimental
diesel engine
Based on the advantages and disadvantages of LPG supply systems, the
study chose LPG supply system manufactured by WTV - United Kingdom
(UK ).


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PUMA
WEIGHTING
FUEL
AVL 735S

C

C

FUEL AIR
CONDITIONER
573C

CONTROL
PANNEL
ENCOMP400

CABLE
BOOM

GREASE
COOLER
AVL554

RUB OUT
PULLING
THA 100

P
P

FEM

WATER COOLER
CONDITIONẺ AVL
553C

POWER
BRAKES
APA
404/6PA

Engine
FAWDE

Figure 4.2. Diagram of experimental equipment

LPG is contained in a 3mm steel cylindrical container with the
capacity of 12 liter. LPG flow fed into the engine is adjusted by quantitative
valve, this valve is controlled by the knob. During the running process, the
amount of LPG will change, depending on the pressure in the charging pipe
of the engine. Every parts of the selected LPG system has a simple and
lightweight structure, it can be easily arranged in the engine compartment
without reconstructing the structure of car. Diagram of the LPG supply to
the engine is shown in Figure 4:12 .


1. Filters;
2. Reduced pressure
vaporizers;
3. Pipeline connected
to the load pressure
sensor;
4. LPG pipeline to the
nozzle;
5.Intake Manifold;
6. Generators;

7. Blowers;
8. Belt;

Figure 4:12. Layout of LPG supply and engine fuel system

15. LPG tank.

9. Pipes to water
tanks;
10. High pressure
pumps;
11. Hot water pipe in;
12. Hot water pipe
out;
13. Filters;
14. LPG line;

16


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4.4 . Experimental procedure
4.4.1 . Experimental conditions
To ensure stable operation of the engine during the testing, all the
engine’s parts must be tested and maintained before installation. Test strips
are also tested and calib devices (?) before testing.
LPG fuel and diesel fuel are inspected by Quality - Measurement
Testing Center , Petroleum Company I.
4.4.2 . The experiment of measuring exhaust from original diesel engine

* Testing Cycle
The study selected running mode according to ECE R49 test cycle to
indentify the engine's emission.
*The content of experiment :
Experimental procedure was conducted according to the following
steps :
Step 1 . Measuring power , torque motors :
Step 2 . Measuring the smoke .
Step 3 . Entering the parameters of the test cycle on the controlling
software .
Step 4 . Measuring engine ‘s exhaust according to the cycle set.
Step 5 . Weigh the filter paper to determine PM emission .
4.4.3 . The experiment of measuring exhaust of diesel – LPG dual fuel
engine
Step 1 . The engine runs on the dynamometer at speed mode
corresponding to the largest torque and 100 % loading, observe fuel level
supplying for the cycle on the control screen ( Figure 4.16 ) . AVL Fuel
Mas Flow Meter Fuel Measuring Equipment connected directly with the
display will indicate the amount of fuel providing for the cycle.
Step 2 . Adjust the brace rod to reduce diesel fuel consumption down
to 90 % , observe the fuel reduction for cycle on the control screen .
Step 3 . Keep the amount of diesel fuel and adjust the LPG amount
spraying into charging pipe until engine ‘s power displayed on the screen is
equipvalent to the initial value when running 100 % diesel .
When the engine is running stably , conducting the same experimental
steps with diesel engine .
Continue to decrease the amount of diesel down to 80 % and conduct
the same steps as above .
After finishing the running test, separate the results and weigh volume

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of particles the same as running the original engine .
4.5 . Testing results and evaluation
4.5.1 . EURO standard on the emission of diesel engine
Our country is applying EURO II standard. EURO standard on
emission of diesel engine is presented in Table 4.1 .
4.5.2 . Evaluation the results of testing engine
The results in Figure 4.17 shows the characteristic of FAWDE 4DX23 engine. The experimental results show that the engine achieved
maximum torque of 308.9 Nm at the rate of 2000 rounds / minute and
maximum power of 82.03 kW at a speed of 2800 rounds / minute . Capacity
and torque value obtained from experiments are not much different from
specifications of the manufacturer .
4.5.3 . Assessing the quality of emission of diesel engine when using diesel
– LPG dual fuel
4.5.3.1 . CO Emission
Diesel
LPG_10
LPG_20

Figure 4.19. CO emission in the testing modes
according to ECE R49 cycle


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4.5.3.2. HC Emission

Diesel

LPG_10
LPG_20

Figure 4.20. HC emission in the testing modes
according to ECE R49 cycle

4.5.3.3. Nox Emission
Diesel
LPG_10
LPG_20

Figure 4.21. NOx emission in the testing modes
according to ECE R49 cycle

The results in Figure 4.19 and 4.20 show the CO and HC emission of
the testing engine when using orginal diesel and diesel - LPG dual fuel. The
results on the graph shows that, the LPG injection on charging pipe of diesel
engine, the HC and CO emission increased. Average CO value at the modes
with LPG rate replacing 20 % of diesel increased by 2 times compared with
CO value when using the original diesel, the highest increase of HC in LPG


20

mode replacing 20 % is up to 335 % .
The results in Figure 4:21 shows that, when using diesel - LPG dual
fuel, the content of NOx is reduced. In LPG mode replacing 10 % , the Nox
average emission when testing according to ECE R49 mode decreased by
2.8 % . In LPG mode replacing 20 % , the Nox average emission decreased
by 4.1% .

4.5.3.4 . The smoke
Results of smoke of diesel - LPG engine is presented in Table 4.4 .
Table 4.4 . Results of measuring the smoke of diesel – LPG engine
The smoke at 100% loading (1/m)
Engine’s
speed
(v/ph)

Diesel

Diesel_10

1000

0,394

0,379

-3,8

0,370

-6,1

1200

0,207

0,197

-4,8

0,187

-9,7

1400

0,142

0,134

-5,6

0,125

-12,0

1600

0,086

0,080

-6,9

0,077

-10,0

1800

0,068

0,062

-8,8

0,058

-14,7

2000

0,081

0,074

-8,4

0,068

-16,0

2200

0,120

0,110

-8,2

0,101

-15,9

2400

0,182

0,160

-12,0

0,142

-22,0

2600

0,252

0,217

-13,9

0,186

-26,2

2800

0,342

0,280

-18,1

0,227

-33,6

Average

Comparing
Comparing
Diesel_20
(%)
(%)

-9,1

-16,6

The smoke decreased due to when spraying LPG into, the rate of
cacbon compared to hydro of LPG is smaller than diesel, ie the volume of C
in LPG fuel is lower than diesel so it should reduce the possibility of
formation of soot , lead to the smoke of diesel - LPG lower than the original
diesel engine .
4.5.3.5 . Average emission

Average emission according to ECE R49 test cycle of testing engine is
shown in Table 4.5 .


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Table 4.5 . Average emission of diesel – LPG dual fuel engine
100%
Component
Unit
Diesel_10 Diesel_20
Diesel
CO

g/kW.h

1,502

2,701

3,85

HC

g/kW.h

0,179

0,45

0,78

NOX

g/kW.h

5,853

5,685

5,61

PM

g/kW.h

0,341

0,291

0,268

4.5.4 . Evaluation of simulation and experimental results
4.5.1.1 . Comparison of simulation and experimental results for the original
engines according to ECE R49 cycle
Table 4.7 . Results of comparison of emission between simulation and experiment
of the original engine ECE R49 cycle
Difference
Component
Unit

Simulation
Experiment
(%)
CO

g/kW.h

1,469

1,502

-2,21

NOX

g/kW.h

5,654

5,853

-3,40

Soot/PM

g/kW.h

0,299

0,341

-12,28

Table 4.7 shows the results of FAWDE - 4DX23 - 110 engine
emission based on the ECE R49 cycle when making the simulation and
experiment . The results showed that the different value between simulation
and experiment for NOx and CO emission are not much.
4.5.4.2 . Comparison of simulation and experimental results for diesel LPG engine according to ECE R49 cycle
The comparison shows that CO and NOx emission calculated
according to ECE R49 cycle between simulation and experiment has not
much difference . The different value between simulation and experiment
for CO emission in LPG mode replacing 10 % of diesel and LPG mode
replacing 20 % of diesel is 3,5 % and 3,9 % .
With NOx, deviations between simulation and experiment in LPG
mode replacing 10 % of diesel is 3,9 % and LPG mode replacing 20 % of
diesel is 5.4 % .


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Table 4.8 . Results of comparision of the emission between simulation and
experiment of diesel - LPG engien according to ECE R49 cycle
Diesel_10 Mode

Diesel_20 Mode

Compon
ent

Unit

Simul
ation

CO

g/kW.h

2,606

2,701

-3,5

3,699

3,850

-3,9

NOX

g/kW.h

5,460

5,685

-3,9

5,305

5,610

-5,4

Soot/PM

g/kW.h

0,249

0,291

-14,4

0,223

0,268

-16,7

Experi Differen Simula Experi Difference
ment
ce (%) tion ment
(%)

The value of soot emission / PM between simulation and experiment
in LPG mode replacing 10 % of diesel is 14.4 % , LPG mode replacing 20
% of diesel is up to 16.7 % .

4.6. Conclusion of Chapter IV
The study selected suitable LPG supply system, installed this system
into FAWDE 4DX23 - 110 diesel engine and conducted the research to
determine the composition of the exhaust when using diesel engine and
diesel - LPG dual fuel engine on the modern equipment system.
The empirical results showed that :
When spraying LPG into the diesel charging pipe:
- The smoke reduced at all speeds of running mode .
- CO and HC increased but still met EURO II standard .
- The amount of NOx is 4.2 % when LPG replacing 20 % of diesel
- The amount of PM is 21,4 % when LPG replacing 20 % of diesel
The comparison between simulation and experiment has not much
difference , it showed that the use of AVL - BOOST software to calculate
the components of diesel- LPG emission is acceptable .
GENERAL CONCLUSIONS AND RECOMMENDATIONS
I. General conclusion
1 . The engines using diesel - LPG dual fuel is catching attention of
many scientists. Many developed countries in the world have put their
finance and effort into this issue. In Vietnam, LPG applications for internal
combustion engines has been interested in many studies, but not really indepth. The research results only stopped at using LPG fuel for the engines
but not interested in optimizing fuel supplying system, combustion and


23

pollutant formation yet. This research has studied the combustion process of
diesel - LPG engine and identified exhaust components released into the
environment .
2 . The study has developed a computational model of FAWDE
4DX23 - 110 turbocharged diesel engine’s emission when using diesel fuel

and diesel - LPG dual fuel on AVL BOOST software. The comparison
between simulation and experiment has not much difference, it showed that
the use of AVL - BOOST software to calculate the components of dieselLPG emission is a proper solution.
3 . The study selected and installed completely of LPG supply on
FAWDE 4DX23 - 110 turbocharged diesel engine to convert a diesel engine
into diesel - LPG dual fuel engine. The installation of LPG supply system
does not change the structure of the original engine .
4 . Experimental results on sync dynamometer on modern emission of
AVL ( Austria ) at National Testing Centre showed that When replacing 20
% LPG by diesel , the smoke reduced in all working speeds of the engine ,
CO and HC increased but still met EURO II standard , NOx ‘s reduction is
4,2 % , PM is 21.4 %.
II . Recommendations
Based on the research results, the thesis has some recommendations :
1 . Applying research’s plan to reduce dust and solve the requirements
of energy replacing the diesel engine mounted on cars running in major
metropolitan areas.
2 . Using gases oxidising filters to solve the increase of CO and HC of
engine using diesel - LPG dual fuel.
3 . There should have more researches to optimize the mixing rate of
LPG in diesel- LPG dual - fuel engine.