Investigations into CI Diesel Engine Performance and Emission Characteristics using Biodiesel with EGR Technique

Investigations into CI Diesel Engine Performance and Emission Characteristics using Biodiesel with EGR Technique

Vijayalakshmi Chunduri1,G Bharath Goud 2 , C T Dheerajkumar Singh 3

1M. Tech in Thermal Engineering, JNTUHCEH, Hyderabad. 2 M. Tech in Thermal Engineering, JNTUHCEH, Hyderabad. 3M. Tech in Computational Fluid Dynamics, UPES, Dehradun.

Abstract:- Energy in the form of fossil fuels have been a matter of great concern for human consumption. There is a need to increase energy supplies to meet basic needs and to do it in a way that promotes sustainable development. Now days, the stringent regulations have been implemented on emission control. Apart from this, it is learnt that the fossil fuels are going to be depleted in near future. In order to meet the forthcoming demand of fossil fuels, there is a need to search alternate fuels like biodiesel, hydrogen, CNG etc. Many problems can be sort out by using biodiesel blends like carbon dioxide, carbon monoxide and hydro carbon emissions. Along with this fuel ignition quality is increased as biodiesel has high cetane number than diesel. In this work an attempt is to be made to use biodiesels in place of diesel fuels. It is known that the most of the biodiesels are oxygenated fuels. Due to the presence of excess oxygen in biodiesels may lead to more emission of NOx as compared to conventional fuel engine. Further the high temperature combustion may be takes place with this sort of fuels. Hence to reduce NOx emissions and to have low temperature combustion processes the exhaust gas recirculation process may be implemented in this work.experimental investigation is done under different loading circumstances in a single cylinder four stroke, direct injected, water-cooled, single naturally aspirated kirloskar diesel engine is used for investigation.

Keywords: Biodiesel, EGR, NOx, emissions, performance.

INTRODUCTION

Petroleum fuel is a non-renewable source of energy. The petroleum reserves have been depleting and there is rise in petroleum prices. But there is an enormous upsurge in number of vehicles each year which has regenerated interest in alternative fuels. The biodiesel has emerged as alternative for diesel fuel due to its renewable nature, better

gnition quality, comparable energy content, higher flash point. Biodiesel refers to a vegetable oil or animal fat- based diesel fuel consisting long chain of esters. It is made by chemically reacting the lipids with an alcohol producing fatty acid esters. A lot of researches have been conducted on internal combustion engines using biodiesel fuel and it shows that the engines produce less carbon monoxide, smoke emissions and unburned hydrocarbon compared to diesel fuel but higher NOx emission. Diesel engine combustion yields large amounts of NOx because of high flame temperatures in presence of ample oxygen and nitrogen in the combustion chamber. Upsurged environmental concerns and tougher emission norms have led to the development of advanced engine technologies to reduce NOx. Exhaust Gas Recirculation is one of the most efficient methods to decrease NOx emission in diesel engine.

EGR TECHNIQUE

Exhaust Gas Recirculation (EGR) is one of the widely used technique to reduce NOx emission gases. This technique involves mixing of inlet air with controllable amount of exhaust gases.A valve is usually used to control the flow of gas based on requirement, and the valve may be closed completely if necessary.Recirculating of burnt gas (which takes no further part in combustion) into oxygen rich air reduces the proportion of the cylinder contents available for combustion.This leads to correspondingly lower heat release and peak cylinder temperature, and reduces the formation of NOx as fresh air charge is decreased.

EXPERIMENTAL TEST SETUP:

A four stroke, direct injected, water-cooled, single cylinder, naturally aspirated diesel engine is used for investigation. The base engine specifications are presented in table.

All the exhaust gases were measured by using exhaust gas analyzer as shown in Figure 2.

• The experiments were conducted at six load levels, viz. 2kg, 4kg, 6kg, 8kg, 10kg, 12kg using Eddy current dynamometer at different speeds.

• The mass flow rate of air is measured using a manometer setup by Air Box method. Fuel flow rate is measured by a gravimetric type Fuel consumption meter.

• Pressure and temperature sensors are mounted at important locations in engine exhaust, water inlet, water outlet, air intake, lube oil for online recording of pressure and temperature values using a Digital Dyno Controller unit and Data Acquisition System.

• Emission characteristics such as Carbon monoxide (CO), Hydro carbon (HC) and carbon dioxide (CO2) were measured by using exhaust gas analyzer.

• All the readings were carried out using ARAI EDACS controller setup and the readings were stored in a personal computer automatically.

• The Schematic of experimental setup is shown in Figure1.

Figure1: Computerized I C Engine setup.

Figure2: Multiple Gas Analyzer

MEASUREMENT METHOD:

The performance and emission characteristics of an engine can be measured with the help of fuel consumption measuring unit, Volt meter, Ammeter, Tachometer, Thermocouples and emission measurement. Starting from no load observation was recorded at 20%, 40%, 60%, 80% and 100% of rated load.

Exhaust emission analysis: For measuring smoke opacity and emission gases, exhaust gas analyzer was used for measuring unburnt Hydrocarbon, Carbon Dioxide, Carbon Monoxide and Nitrogen Oxide.

Measurement of gas recalculated air: The quantity of EGR is to be measured and controlled accurately bypass for exhaust gas is provided along with manually controlled EGR valve and orifice meter is designed and installed to measure volumetric flow rate of EGR.

RESULTS AND DISCUSSIONS

The experimental investigations are carried out using the above said alternative fuel oil and Diesel on the test engine with Exhaust Gas recirculation. The detailed analyses of these results are discussed in this section in the form of graphs. The salient features of these graphs would be outlined in the following sections.

ENGINE PERFORMANCE AND EMISSIONS FOR DIESEL AND BIODIESEL WITH DIFFERENT RATES OF EGR

Brake thermal efficiency vs

brake power

30

Diesel

25

20

Animal

Tallow

0

EGR

0

2

4

BP in KW

5

10

15

Brake Thermal Efficiency %

Figure 3: Variation Of Brake Thermal Efficiency With Brake Power

Figure3.Shows the variation of Brake Thermal efficiency of the engine with respect to Brake power for Diesel and Animal Tallow Biodiesel for 10% EGR and 20% EGR. From the above variation it can be concluded that the Brake thermal efficiency increases with increase in brake power whic is proportional to load for Diesel and Biodiesel used in this project work with 10% EGR and 20% EGR .From the above curves the Brake thermal efficiency decreases with increase in % of EGR in this project work. The maximum Brake thermal efficiency obtained for Diesel is 27.35% at 12 kg load in this project work.

SFC vs Brake power

1.2

Diesel

1

Animal

Tallow

0.8

0.6

Diesel

10% EGR

0.4

AT 10% EGR

0.2

AT 20%

EGR

0

0

2

4

BP in KW

Diesel

20% EGR

AT 10%

EGR

AT 20%

Diesel

20% EGR

Diesel

10% EGR

SFC Kg/KWHr

Figure 4: Variation Of Specific Fuel Consumption With Brake Power

Figure 4 shows the variation of Specific fuel consumption of the engine with respect to Brake power for Diesel and Animal Tallow Biodiesel with 10% EGR and 20% EGR. From the above variation it can be concluded that the Specific Fuel Consumption decreases with increase in brake power which is proportional to load for both Diesel and Biodiesel. The Specific Fuel Consumption with respect to brake power at 20% EGRs slightly higher in comparison with Specific Fuel Consumption with respect to brake power at 10% EGR for both Diesel and Animal tallow biodiesel used in this project work.

The Specific Fuel Consumption is lower for Diesel when compared with that of Animal tallow biodiesel at both 10% EGR and 20% EGR respectively. The minimum Specific Fuel Consumption obtained for Diesel is 0.297kg/hr in this project work.

Exhaust gas temperature vs

brake power

NOx vs Brake power

350

Diesel

300

2500

BP in KW

4

2

0

0

AT 20 %

EGR

500

AT 10%

EGR

1000

Diesel

20% EGR

1500

Diesel

10% EGR

2000

Animal

Tallow

Diesel

3000

AT 20%

50 EGR

0

0 2 4

BP in KW

AT 10%

EGR

100

Diesel

20% EGR

150

Diesel

10% EGR

250

200

Animal

Tallow

Exhaust gas temperature in C

N0x in ppm

Figure 5: Variation Of Exhaust Gas Temperature With Brake Power

Figure 5Shows the variation of Exhaust gas temperature of the engine with respect to brake power for Diesel and animal tallow biodiesel for all rates of EGR. The Exhaust gas temperature increases with increase in load. The Exhaust gas temperature for diesel is higher compared with animal tallow biodiesel. The Exhaust gas temperature decreases with increase in rate of EGR for both Diesel and Animal Tallow Biodiesel used in this project.

Figure 6: Variation OfNox Emission With Brake Power

Figure 6 shows the variation of oxides of Nitrogen emissions from the engine with respect to Brake power for Diesel and Animal Tallow Biodiesel at 10% EGR and 20% EGR. From the above variation it can be concluded that the oxides of Nitrogen increases with increase in brake power which is proportional to load for both Diesel and Animal tallow Biodiesel at 10% EGR and 20% EGR.The NOxemission for Animal tallow biodiesel is lower compared with the diesel. The NOxemission for Animal tallow biodiesel at 10% EGR is lower compared with the Diesel at 10% EGR. The NOxemission for Animal tallow biodiesel at 20% EGR is lower compared with the Diesel at 20% EGR. The NOxemissions decrease with increase in

%EGR. The NOxemission for Diesel at 20% EGR is lower compared with the Diesel at 10% EGR. The NOxemission for Animal tallow biodiesel at 20% EGR is lower compared with the Animal tallow biodiesel at 10% EGR.

Hydrocarbons vs Brake power

40 Diesel

35

30

25

20

Animal

Tallow

Diesel 10% EGR

Diesel 20% EGR

AT 10% EGR

15

AT 20% EGR

10

5

0

0

2

4

BP in KW

HC in ppm

C02 in %

Figure 7: Variation Of Hydrocarbon Emission With Brake Power

Figure 7 shows the variation of Hydrocarbon emissions

CO2 vs Brake power

10

9

8

7

6

5

4

3

2

1

0

0 2 4

BP in KW

Diesel

Animal Tallow

Diesel 10% EGR

Diesel 20% EGR

AT 10% EGR

AT 20% EGR

from the engine with respect to Brake power for Diesel and Animal Tallow Biodiesel at 10% EGR and 20% EGR. From the above variation it can be concluded that the Hydrocarbon emissions increases with increase in brake power which is proportional to load for both Diesel and Animal tallow Biodiesel at 10% EGR and 20% EGR. The Hydrocarbon emissions high at higher loads and low at lower loads for Diesel and Biodiesel for different rates of EGR used in this project. Hydrocarbon, carbon monoxide and carbon dioxide emissions are lower for diesel than animal tallow biodiesel. Hydrocarbon, carbon monoxide and carbon dioxide emissions increases with increase in rate of EGR because they depended on the combustion temperature. Mainly low combustion temperature regions such as boundary layer near the walls cause the formation of these emissions. From the experiment it was found that emission of HC, CO and CO2 increased with increasing EGR rates, the possible reason may be decrease in combustion temperature or exhaust gas temperature.

Figure 8: Variation Of Co2 Emission With Brake Power

Figure 8 shows the variation of emission of CO2 from the engine with respect to Brake power for Diesel and Animal Tallow Biodiesel at 10% EGR and 20% EGR.From the above variation it can be concluded that the % of CO2 emission increases with increase in brake power which is proportional to load for both Diesel and Animal tallow Biodiesel at 10% EGR and 20% EGR respectively. The CO2 emissions increase with increase in %EGR. The CO2 emissions for Diesel with 10% EGR and 20% EGR are higher compared with the Diesel without EGR. The CO2 emissions for Animal tallow biodiesel with 10% EGR and 20% EGR are higher compared with the Animal tallow without EGR.

CONCLUSION

It is observed from the experiment that engine operated with biodiesel using EGR technique have reduced emission values compared with engine operated with diesel using EGR. It has observed from figures that brake thermal efficiency for Bio-diesel blend is higher than base line data of diesel. It is also observed that there is reduction in the emission of Hydrocarbon HC, CO, NOx& smoke bio diesel operated with EGR.

REFERENCES

1. Experimental Investigation of a Diesel-Biodiesel Fuelled Compression Ignition Engine with Exhaust Gas Recirculation (EGR) Achuthanunni V, Baiju B

2. Experimental Studies on Emission and Performance Characteristics in Diesel EngineUsing Bio-Diesel Blends And EGR(Exhaust Gas Recirculation) Pooja Ghodasara1,

   Mayur Ghodasara2

3. Biodiesel as an Alternate Fuel in a Diesel Engine with the Cooled Exhaust Gas RecirculationA Measure to Reduce Harmful Emissions S. Adinarayana1, YMC Sekhar2

4. Iida N. Alternative fuels and homogeneous charge compression ignition combustion technology. SAE paper no. 972071; 1997

5. A Study on Reduction of Oxides of Nitrogen with Jatropha Oil Based Bio Diesel NitinShrivastava, Dr. S.N. Varma