heat recovery & performance characterization of 4-stroke c.i

Heat Recovery & Performance Characterization Of 4-Stroke C.I. Engine Using

Turbocharger & IntercoolerAshish Jain#1, Jikisha Patel#2, Asst. Prof. K.P.Trivedi#3

#Mechanical Engineering Department, L.D. College of EngineeringAhmedabad, India.

[email protected]@yahoo.co.in

[email protected]

Abstract In order to achieve proposed fuel economy requirements, engines must make better use of the available fuel energy and the utilization of exhaust waste heat is now well known. Regardless of how efficient the engine is, there will still be a significant fraction of the fuel energy that is rejected in the exhaust and coolant streams.

This problem would force mankind to think about the efficient use of available fuel. Turbocharging is one of the efficient methods to increase the efficiency of I.C. Engine which is used in large scale throughout the world. And due to its advantages it is very necessary to use. Turbocharging is means of increasing engine performance & power output of I.C. Engines by forcing the compressed air into the combustion chamber of engine thereby the mass flow rate of air increases allowing more fuel to be burned & this leads to an increase in power output & improvement in engine performance. This can improve power to weight ratio, more thermal efficiency over naturally aspirated engine & supercharged engine. It improves volumetric efficiency & control over exhaust gas emission. The idea to be investigated here is based essentially on the fact that, the exhaust gases from diesel engines represent an appreciable energy loss to the environment. Therefore, it is possible that some of this waste energy could be used for charge air cooling as well as improving the thermal efficiency of the diesel engine.

Keywords Heat Recovery, Diesel Engines, Engine Performance, Turbocharger, Intercooler.

I. INTRODUCTION TO TURBOCHARGING

A turbocharger is an auxiliary device as an integral part of all large multicylinder diesel engines. Turbocharger is an exhaust gas driven forced induction device used in I.C. Engine to improve engine performance by forcing compressed air into the combustion chamber allowing more fuel to be burned resulting in a large power output & the method is called turbo-charging. Turbocharging, as defined earlier, are turbine driven Superchargers. These devices use the energy of exhaust gases to run the turbine that in turns the air-compressor that provides high-pressure air to the engine.

Figure1. TurbochargerTurbochargers are a type of forced induction system. They

compress the air flowing into the engine. The advantage of compressing the air is that it lets the engine squeeze more air into a cylinder, and more air means that more fuel can be added. Therefore, you get more power from each explosion in each cylinder. A turbocharged engine produces more power overall than the same engine without the charging. This can significantly improve the power-to-weight ratio for the engine.

II. DIFFERENT OTHER METHODS OF IMPROVINGENGINE PERFORMANCE

The various methods which can be employed for improvement of performance of an engine are:

1. Increasing speed of the engine,2. Use of higher compression ratio,3. Utilization of exhaust gas energy,4. Use of two stroke cycle.5. Improving volumetric efficiency of the engine,

&6. Increasing the charge density.

13-14 May 2011 B.V.M. Engineering College, V.V.Nagar,Gujarat,India

National Conference on Recent Trends in Engineering & Technology

III. DIFFERENCE BETWEEN TURBOCHARGER &SUPERCHARGER

Figure 2: Supercharger & TurbochargerA mechanical supercharger has a belt that connects directly

to the engine while a turbocharger receives its power from the exhaust stream. Both turbochargers & superchargers are forced induction systems. A turbo/supercharged engine produces more power overall than the same engine without the charging. In theory, a turbocharger is more efficient because it is using the Wasted energy in the exhaust stream for its power source. On the other hand, a turbocharger causes some amount of back pressure in the exhaust system & tend to provide lesser boost until the engine is running at higher RPMs. Superchargers are easier to install & maintain but tend to be more expensive.

IV. WORKING OF TURBOCHARGER

A turbocharger has two main parts the compressor & the turbine.

Figure 3: sectional view of turbochargerThe turbocharger is bolted to the exhaust manifold of the

engine. The exhaust from the cylinders spins the turbine,which works like a gas turbine. A shaft to the compressor connects the turbine, which is located between the air filter & the intake manifold. The compressor pressurizes the air going into the pistons. On the other end of the shaft that the turbine is attached to, the compressor is a type of centrifugal pump; it draws air in at the center of its blades & flings it outward as it spins. In order to handle speeds of up to 150,000 rpm, the turbine shaft has to be supported very carefully. Most bearings would explode at speeds like this, so most turbochargers use a fluid bearing.

Figure 4: Turbocharger connected to an EngineThe exhaust from the cylinders passes through the turbine

blades, causing the turbine to spin. The more exhaust that goes through the blades, the faster they spin. The higher temperature is a volumetric efficiency downgrade for both types of engine. The pumping effect heating can be alleviated by after cooling (sometimes called inter-cooling).

V. OBJECTIVE OF TURBOCHARGING

The purpose of turbocharged engines is;1) To increase the power output of the engine by

increasing the density of charge at intake,2) To reduce the weight to power ratio. It is very

useful in case of air craft, racing cars & marine applications.

VI. ADVANTAGES OF TURBOCHARGING

1) Due to the lower volumetric displacement of the turbo engine, frictional & thermal losses are less.

2) The power-to-weight ratio, i.e. kilowatt (power output)/kilograms (engine weight); of the exhaust gas turbocharged engine is much better than that of the naturally aspirated engine.

3) The turbo engines installation space requirement is smaller than that of a naturally aspirate engine with the same power output.

4) The high altitude performance of a turbocharged engine is significantly better. Because of reduced overall size, the sound radiating outer surface of a turbo engine is smaller; it is therefore less noisy than a naturally aspirated engine with identical output. The turbocharger itself acts as an additional silencer.

5) No gearing is required between the gas turbine & compressor.

6) It is very simple for high speed engine.7) Exhaust of the engine becomes considerably quite.



VII. LIMITATIONS OF TURBOCHARGING

1) Increase in fuel consumption at low power outputs.

2) Total cost increases.3) Causes turbo lag at low engine speeds.

VIII. EXPERIMENTAL SETUP

Figure 5: (a) Test rig (b) TC with Intercooler connected to an Engine

This experimental setup consists of a 4 stroke, single cylinder diesel engine coupled with a Brake rope dynamometer. This type of engine is best suitable for vehicles which operate at varying loads. Various measurements provided enables to evaluate the performance of the engine at various loads.

IX. RESULTS & DISCUSSION

Graph 1 Load versus mass flow rate

Graph 2 Brake Power versus Brake Thermal Efficiency

Graph 3 Speed versus Brake Specific Fuel Consumption

Graph 4 Pie Chart on the basis of Heat Balance Sheet without TC

Graph 5 Pie Chart On The Basis Of Heat Balance Sheet with TC

1) Graph 1 shows that as load increases mass of fuel consumption per hour increases but in turbocharged engine, it is less than the naturally aspirated engine due to increase in air flow rate.

2) Graph 2 shows that as brake power increases brake thermal efficiency increases but in case of turbocharged engine, brake thermal efficiency is higher than unturbocharged engine due to decrease in fuel consumption.

3) On the basis of this Graph 3, at lower speed bsfc is higher up to certain limit then it is somewhat constant, but in turbocharged engine it is less than unturbocharged engine.



X. CONCLUSION

By studying the observations, results & the graphs; it may be concluded that

(for constant load speed & B.P.)1. The brake thermal efficiency is increased by 6 to 7 %.2. Volumetric efficiency increases by 4 to 6 %.3. It is suitable to use in high speed diesel engines.4. Mass of air per hour is increased thereby more fuel is

to be burned i.e. from 8 to 9 kg/hr.5. Mass flow rate of fuel per hour decreases thereby bsfc

is reduced from 0.25 to 0.90 kg/hr.6. The waste heat recovered from the exhaust gases is

obtained about 5 to 10 %.

REFERENCES[1] Aiyoshizaw E., Hasegaw M., Kawashim J., Muranak S. 2000,

Combustion characteristics of a small DI diesel engine, JSAE Review 21 (2000) pp. 241-263.

[2] Bangal D.B., Tathe D.W., Patil P.C. 2010, Methods of Improving Performance of I.C. Engine by Turbocharging, National Conference on Recent Trends in I.C. Engines & Automobile, pp. 182-185.

[3] Barelli L., Bidini G., Bonucci F. - 2009, Diagnosis methodology for the turbocharger groups installed on a 1 MW internal combustion engine, Journal of Applied Energy 86 (2009) pp. 27212730.

[4] Brace C.J., Cox A., Hawley J.G.,Vaughan N.D. & Wallace F.W., University of Bath; Horrocks R.W. & Bird G.L., Ford Motor Company; Transient Investigation of Two Variable Geometry

Turbochargers for Passenger Vehicle Diesel Engines, SAE Technical Paper Series (1999).

[5] Cheong J., Cho S., Kim C. - 2000, Effect of Variable Geometry Turbocharger on HSDI Diesel Engine, Seoul 2000 FISITA World Automotive Congress, 2000, Seoul, Korea.

[6] Descombes G., Boudigues S. - 2009, Modeling of waste heat recovery for combined heat and power applications, Journal of Applied Thermal Engineering 29 (2009) pp. 26102616.

[7] Eriksson L., Nielsen L., Brug J., Bergstriim J., Pettersson F. and Andersson P. - 2002, Modeling Of A Turbocharged SI Engine, Annual Reviews in Control 26 (2002) pp. 129-137.

[8] Erol A., Ismet C. - 2005, A diesel engines performance and exhaust emissions, Journal of Applied Energy 80 (2005) pp. 1122.

[9] Galindo J., Guardiola C., Desantes J., Dolz V. - 2010, Air mass flow estimation in turbocharged diesel engines from in-cylinder pressure measurement, Journal of Experimental Thermal and Fluid Science 34 (2010) pp. 3747.

[10] Karabektas M. - 2009, The effects of turbocharger on the performance and exhaust emissions of a diesel engine fuelled with biodiesel, Journal of Renewable Energy 34 (2009) pp. 989993.

[11] Kunanoppadon J. - 2010, Thermal Efficiency of a Combined Turbocharger Set with Gasoline Engine, American Journal of Engineering and Applied Sciences 3 (2): pp. 342-349.

[12] Moulin P., Grondin O. and Fontvieille L. - 2009, Control of a two stage turbocharger on a Diesel engine, Joint 48th IEEE Conference on Decision and Control and 28th Chinese Control Conference: pp. 5200-5206.

[13] Richard stone - 1999 - Introduction to Internal combustion engine/ society of automotive engineering. Inc., pp. 372-406.

[14] Uchida H. 2007, Trend of Turbocharging Technologies, R&D Review of Toyota CRDL, Vol. 41, No. 3.

[15] Weerasinghe W., Stobart R., Hounsham S. - 2010, Thermal efficiency improvement in high output diesel engines a comparison of a Rankine cycle with turbo-compounding, Journal of Applied Thermal Engineering 30 (2010) 2253- 2256.



Heat Recovery & Performance Characterization

Of 4-Stroke C.I. Engine Using

Turbocharger & Intercooler

Ashish Jain#1, Jikisha Patel#2, Asst. Prof. K.P.Trivedi#3

#Mechanical Engineering Department, L.D. College of EngineeringAhmedabad, India.

[email protected]

[email protected]

[email protected]

Abstract In order to achieve proposed fuel economy requirements, engines must make better use of the available fuel energy and the utilization of exhaust waste heat is now well known. Regardless of how efficient the engine is, there will still be a significant fraction of the fuel energy that is rejected in the exhaust and coolant streams.

This problem would force mankind to think about the efficient use of available fuel. Turbocharging is one of the efficient methods to increase the efficiency of I.C. Engine which is used in large scale throughout the world. And due to its advantages it is very necessary to use. Turbocharging is means of increasing engine performance & power output of I.C. Engines by forcing the compressed air into the combustion chamber of engine thereby the mass flow rate of air increases allowing more fuel to be burned & this leads to an increase in power output & improvement in engine performance. This can improve power to weight ratio, more thermal efficiency over naturally aspirated engine & supercharged engine. It improves volumetric efficiency & control over exhaust gas emission. The idea to be investigated here is based essentially on the fact that, the exhaust gases from diesel engines represent an appreciable energy loss to the environment. Therefore, it is possible that some of this waste energy could be used for charge air cooling as well as improving the thermal efficiency of the diesel engine.

Keywords Heat Recovery, Diesel Engines, Engine Performance, Turbocharger, Intercooler.

I. Introduction TO TURBOCHARGING

A turbocharger is an auxiliary device as an integral part of all large multicylinder diesel engines. Turbocharger is an exhaust gas driven forced induction device used in I.C. Engine to improve engine performance by forcing compressed air into the combustion chamber allowing more fuel to be burned resulting in a large power output & the method is called turbo-charging. Turbocharging, as defined earlier, are turbine driven Superchargers. These devices use the energy of exhaust gases to run the turbine that in turns the air-compressor that provides high-pressure air to the engine.

Figure1. Turbocharger

Turbochargers are a type of forced induction system. They compress the air flowing into the engine. The advantage of compressing the air is that it lets the engine squeeze more air into a cylinder, and more air means that more fuel can be added. Therefore, you get more power from each explosion in each cylinder. A turbocharged engine produces more power overall than the same engine without the charging. This can significantly improve the power-to-weight ratio for the engine.

II. DIFFERENT OTHER METHODS OF IMPROVING ENGINE PERFORMANCE

The various methods which can be employed for improvement of performance of an engine are:

1. Increasing speed of the engine,

2. Use of higher compression ratio,

3. Utilization of exhaust gas energy,

4. Use of two stroke cycle.

5. Improving volumetric efficiency of the engine, &

6. Increasing the charge density.

III. DIFFERENCE BETWEEN TURBOCHARGER & SUPERCHARGER

Figure 2: Supercharger & Turbocharger

A mechanical supercharger has a belt that connects directly to the engine while a turbocharger receives its power from the exhaust stream. Both turbochargers & superchargers are forced induction systems. A turbo/supercharged engine produces more power overall than the same engine without the charging. In theory, a turbocharger is more efficient because it is using the Wasted energy in the exhaust stream for its power source. On the other hand, a turbocharger causes some amount of back pressure in the exhaust system & tend to provide lesser boost until the engine is running at higher RPMs. Superchargers are easier to install & maintain but tend to be more expensive.

IV. WORKING OF TURBOCHARGER

A turbocharger has two main parts the compressor & the turbine.

Figure 3: sectional view of turbocharger

The turbocharger is bolted to the exhaust manifold of the engine. The exhaust from the cylinders spins the turbine, which works like a gas turbine. A shaft to the compressor connects the turbine, which is located between the air filter & the intake manifold. The compressor pressurizes the air going into the pistons. On the other end of the shaft that the turbine is attached to, the compressor is a type of centrifugal pump; it draws air in at the center of its blades & flings it outward as it spins. In order to handle speeds of up to 150,000 rpm, the turbine shaft has to be supported very carefully. Most bearings would explode at speeds like this, so most turbochargers use a fluid bearing.

Figure 4: Turbocharger connected to an Engine

The exhaust from the cylinders passes through the turbine blades, causing the turbine to spin. The more exhaust that goes through the blades, the faster they spin. The higher temperature is a volumetric efficiency downgrade for both types of engine. The pumping effect heating can be alleviated by after cooling (sometimes called inter-cooling).

V. OBJECTIVE OF TURBOCHARGING

The purpose of turbocharged engines is;

1) To increase the power output of the engine by increasing the density of charge at intake,

2) To reduce the weight to power ratio. It is very useful in case of air craft, racing cars & marine applications.

VI. ADVANTAGES OF TURBOCHARGING

1) Due to the lower volumetric displacement of the turbo engine, frictional & thermal losses are less.

2) The power-to-weight ratio, i.e. kilowatt (power output)/kilograms (engine weight); of the exhaust gas turbocharged engine is much better than that of the naturally aspirated engine.

3) The turbo engines installation space requirement is smaller than that of a naturally aspirate engine with the same power output.

4) The high altitude performance of a turbocharged engine is significantly better. Because of reduced overall size, the sound radiating outer surface of a turbo engine is smaller; it is therefore less noisy than a naturally aspirated engine with identical output. The turbocharger itself acts as an additional silencer.

5) No gearing is required between the gas turbine & compressor.

6) It is very simple for high speed engine.

7) Exhaust of the engine becomes considerably quite.

VII. LIMITATIONS OF TURBOCHARGING

1) Increase in fuel consumption at low power outputs.

2) Total cost increases.

3) Causes turbo lag at low engine speeds.

VIII. EXPERIMENTAL SETUP

Figure 5: (a) Test rig (b) TC with Intercooler connected to an Engine

This experimental setup consists of a 4 stroke, single cylinder diesel engine coupled with a Brake rope dynamometer. This type of engine is best suitable for vehicles which operate at varying loads. Various measurements provided enables to evaluate the performance of the engine at various loads.

IX. RESULTS & DISCUSSION

Graph 1 Load versus mass flow rate

Graph 2 Brake Power versus Brake Thermal Efficiency

Graph 3 Speed versus Brake Specific Fuel Consumption

Graph 4 Pie Chart on the basis of Heat Balance Sheet without TC

Graph 5 Pie Chart On The Basis Of Heat Balance Sheet with TC

1) Graph 1 shows that as load increases mass of fuel consumption per hour increases but in turbocharged engine, it is less than the naturally aspirated engine due to increase in air flow rate.

2) Graph 2 shows that as brake power increases brake thermal efficiency increases but in case of turbocharged engine, brake thermal efficiency is higher than unturbocharged engine due to decrease in fuel consumption.

3) On the basis of this Graph 3, at lower speed bsfc is higher up to certain limit then it is somewhat constant, but in turbocharged engine it is less than unturbocharged engine.

X. CONCLUSION

By studying the observations, results & the graphs; it may be concluded that

(for constant load speed & B.P.)

1. The brake thermal efficiency is increased by 6 to 7 %.

2. Volumetric efficiency increases by 4 to 6 %.

3. It is suitable to use in high speed diesel engines.

4. Mass of air per hour is increased thereby more fuel is to be burned i.e. from 8 to 9 kg/hr.

5. Mass flow rate of fuel per hour decreases thereby bsfc is reduced from 0.25 to 0.90 kg/hr.

6. The waste heat recovered from the exhaust gases is obtained about 5 to 10 %.

References

[1] Aiyoshizaw E., Hasegaw M., Kawashim J., Muranak S. 2000, Combustion characteristics of a small DI diesel engine, JSAE Review 21 (2000) pp. 241-263.

[2] Bangal D.B., Tathe D.W., Patil P.C. 2010, Methods of Improving Performance of I.C. Engine by Turbocharging, National Conference on Recent Trends in I.C. Engines & Automobile, pp. 182-185.

[3] Barelli L., Bidini G., Bonucci F. - 2009, Diagnosis methodology for the turbocharger groups installed on a 1 MW internal combustion engine, Journal of Applied Energy 86 (2009) pp. 27212730.

[4] Brace C.J., Cox A., Hawley J.G.,Vaughan N.D. & Wallace F.W., University of Bath; Horrocks R.W. & Bird G.L., Ford Motor Company; Transient Investigation of Two Variable Geometry Turbochargers for Passenger Vehicle Diesel Engines, SAE Technical Paper Series (1999).

[5] Cheong J., Cho S., Kim C. - 2000, Effect of Variable Geometry Turbocharger on HSDI Diesel Engine, Seoul 2000 FISITA World Automotive Congress, 2000, Seoul, Korea.

[6] Descombes G., Boudigues S. - 2009, Modeling of waste heat recovery for combined heat and power applications, Journal of Applied Thermal Engineering 29 (2009) pp. 26102616.

[7] Eriksson L., Nielsen L., Brug J., Bergstriim J., Pettersson F. and Andersson P. - 2002, Modeling Of A Turbocharged SI Engine, Annual Reviews in Control 26 (2002) pp. 129-137.

[8] Erol A., Ismet C. - 2005, A diesel engines performance and exhaust emissions, Journal of Applied Energy 80 (2005) pp. 1122.

[9] Galindo J., Guardiola C., Desantes J., Dolz V. - 2010, Air mass flow estimation in turbocharged diesel engines from in-cylinder pressure measurement, Journal of Experimental Thermal and Fluid Science 34 (2010) pp. 3747.

[10] Karabektas M. - 2009, The effects of turbocharger on the performance and exhaust emissions of a diesel engine fuelled with biodiesel, Journal of Renewable Energy 34 (2009) pp. 989993.

[11] Kunanoppadon J. - 2010, Thermal Efficiency of a Combined Turbocharger Set with Gasoline Engine, American Journal of Engineering and Applied Sciences 3 (2): pp. 342-349.

[12] Moulin P., Grondin O. and Fontvieille L. - 2009, Control of a two stage turbocharger on a Diesel engine, Joint 48th IEEE Conference on Decision and Control and 28th Chinese Control Conference: pp. 5200-5206.

[13] Richard stone - 1999 - Introduction to Internal combustion engine/ society of automotive engineering. Inc., pp. 372-406.

[14] Uchida H. 2007, Trend of Turbocharging Technologies, R&D Review of Toyota CRDL, Vol. 41, No. 3.

[15] Weerasinghe W., Stobart R., Hounsham S. - 2010, Thermal efficiency improvement in high output diesel engines a comparison of a Rankine cycle with turbo-compounding, Journal of Applied Thermal Engineering 30 (2010) 2253- 2256.

_1363172299.xls

Chart1

0.140.15

0.20.23

0.250.3

0.280.34

without TC

with TC

B.P. in kW/h

bth

Sheet1

B.P.without TCwith TC

50.140.15

100.20.23

200.250.3

300.280.34

To resize chart data range, drag lower right corner of range.

_1363172302.xls

Chart1

57

1015

1520

2530

mf without TC

mf with TC

Load in kg

mf in kW/h

Sheet1

LOADmf without TCmf with TC

557

101015

201520

302530


_1363172294.xls

Chart1

14

6

12

68

heat balance sheet

HEAT BALANCE SHEET WITHOUT TC

Sheet1

heat balance sheet

HE TO BP14

HL TO WJ6

HL TO EG12

HEAT UNACCOUNTED68


_1363172297.xls

Chart1

0.60.5

0.450.35

0.330.28

0.30.25

without TC

with TC

Speed in rpm

Bsfc in kg/kWh

Sheet1

speedwithout TCwith TC

7500.60.5

10000.450.35

12500.330.28

15000.30.25


_1363172292.xls

Chart1

20

5

10

65

heat balance sheet

HEAT BALANCE SHEET WITH TC

Sheet1

heat balance sheet

HE TO BP20

HL TO WJ5

HL TO EG10

HEAT UNACCOUNTED65


heat recovery & performance characterization of 4-stroke c.i

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