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International Journal of Automobile Engineering Research and Development (IJAuERD) ISSN 2277-4785 Vol. 3, Issue 4, Oct 2013, 11-22 © TJPRC Pvt. Ltd.

EXPERIMENTAL ANALYSIS OF OPTIMAL GEOMETRY FOR EXHAUST MANIFOLD OF MULTI-CYLINDER SI ENGINE FOR OPTIMUM PERFORMANCE K. S. UMESH1, V. K. PRAVIN2 & K. RAJAGOPAL3 1

Department of Mechanical Engineering, Thadomal Shahani Engineering College, Mumbai, Maharashtra, India 2

Department of Mechanical Engineering, P.D.A. College of Engineering, Gulbarga, Karnataka, India 3

Former Vice Chancellor, JNT University, Hyderabad, Andhra Pradesh, India

ABSTRACT In internal combustion engines, Brake specific fuel consumption is direct measure of fuel economy of engine whereas volumetric efficiency is one of the prime factors in determining how much power output an engine can generate as compared to its capacity. Exhaust velocity & back pressure are the parameters on which emissions from the engines would depend .The purpose of this research work is to investigate which can be the best geometry for exhaust manifold of the multi-cylinder SI engine. The research work is concentrated on the experimental investigation of 4 different models of exhaust manifold and conclude on best possible design of exhaust of the manifold .Physical models of the two systems were manufactured exhaustive experiments were carried out on them. The analysis has been carried out on two designs an existing one and a modified one. It was observed that the volumetric efficiency improved drastically upon modification in exhaust geometry. Later on both these models were modified by attaching a reducer at its outlet and similar experiments were carried upon them .Attachment of reducer leads to drastic reduction in BSFC. The scope of the research of this work has been stretched to investigate whether all the design modifications which were considered has any impact on the other factors like exhaust velocity, back pressure, exhaust temperature, mechanical efficiency etc.

KEYWORDS: Multi-Cylinder Engine, Exhaust Manifold, Volumetric Efficiency, Existing Model, Modified Model, Reducer, Mechanical Efficiency, B.S.F.C., Thermal Efficiency, Fuel Economy, Optimization

INTRODUCTION In any multi-cylinder IC engine, an exhaust manifold (also known as a header) collects the exhaust gases from multiple cylinders into one pipe. This header is connected to these cylinders through bends. It is attached downstream of the engine and is major part in multi‐ cylinder engines where there are multiple exhaust streams that have to be collected into a single pipe. Exhaust gases comes out of this Header as a single stream of hot exhaust gases through single outlet. When an exhaust stroke starts in multi-cylinder SI engine, the piston moves up the cylinder bore, increasing the pressure. When the exhaust valve opens, the high pressure exhaust gas leaves the cylinder and enters into the exhaust manifold or header after flowing through bends, creating an exhaust pulse comprising three main parts: The high‐pressure head is created by the large pressure difference between the exhaust in the combustion chamber and the atmospheric pressure outside of the exhaust system. As the exhaust gases equalize between the combustion chamber and the atmosphere, the difference in pressure decreases and the exhaust velocity decreases. This forms the medium‐pressure body component of the exhaust pulse. The remaining exhaust gas forms the low‐pressure tail component. This tail component may initially match ambient atmospheric pressure, but the momentum of the high‐ and medium‐ pressure components reduces the pressure in the combustion chamber to a lower‐than‐atmospheric level. This relatively low pressure (known as back pressure) helps to extract all the combustion products from the cylinder. This process is known as scavenging and


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K. S. Umesh, V. K. Pravin & K. Rajagopal

efficiency of this process is thus called scavenging efficiency. Thus back pressure is one of the most critical parameter for exhaust system especially in cases where speed of engine is very high or Engine has very large power capacity. In other words, lower back pressure helps to induct the intake charge during the overlap period when both intake and exhaust valves are partially open the effect is known as scavenging. Scavenging efficiency is function of Length of the exhaust manifold, cross�sectional area, shaping of the exhaust ports and pipe�works influences the degree of scavenging effect and the engine speed range over which scavenging occurs. The magnitude of the exhaust scavenging effect is proportional to the velocity of the high and medium pressure components of the exhaust pulse. Headers are designed to increase the exhaust velocity as much as possible. Obvious way of achieving this is to reduce the diameter of the outlet of exhaust manifold but it brings an disadvantage of rise in back pressure. Exhaustive work has taken place already in this field. Scheeringa et al studied analysis of Liquid cooled exhaust manifold using CFD. Detailed information of flow property distributions and heat transfer were obtained by him to improve the fundamental understandings of manifold operation. A number of computations were performed by him to investigate the parametric effects of operating conditions and geometry on the performance of manifolds. Seenikannan et al analysed a Y section exhaust manifold system experimentally to improve engine performance. His paper investigates the effect of using various models of exhaust manifold on CI engine performance and exhaust emission. Yasar Deger et al did CFD-FE-Analysis for the Exhaust Manifold of a Diesel Engine aiming to determine specific temperature and pressure distributions. The fluid flow and the heat transfer through the exhaust manifold were computed correspondingly by CFD analyses including the conjugate heat transfer. In our own previous work, we experimentally investigated the effect of exhaust manifold geometry on volumetric efficiency of Multi-cylinder SI engine and also verified the results obtained through CFD analysis.

DISCUSSIONS Model Description Two different Models considered for this research work are shown in the figure 1 & 2 respectively. The material used for pipe was SA 106 (grade B). Flange material was IS 2602 (Grade B). Elbows were manufactured using SA 234 WPB.

Figure 1: Existing Model

Figure 2: Modified Model

Both existing model and modified model has header length of 335mm. ID and OD of headers is 52.48 mm & 60.3 mm respectively. In existing model the bend radius is 48 mm and exhaust is on one side as shown in the figure. ID and OD of bend were 35.08mm and 42.86mm respectively. Modified model has bend radius of 100 mm and exhaust is at the centre of header. ID & OD of the bend & exhaust is 52.48mm and 60.3 mm respectively for both models. Length of the outlet of


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Experimental Analysis of Optimal Geometry for Exhaust Manifold of Multi-Cylinder SI Engine for Optimum Performance

exhaust manifold was kept at 220mm and flange was attached at the end to connect it to exhaust muffler. Arrangement was provided on the model as shown in figure to investigate pressure and temperature at distinct points. In order to further investigate the effect of attaching a reducer at the end of the outlet of exhaust manifold a nozzle of length 70mm was attached to the outlet which was cut at length of 50 mm from centerline. At the end of nozzle whose smaller diameter was 38mm an extended pipe of constant cross section was attached. Length of this pipe was 100 mm at the end of which flange was attached in order to attach it to the exhaust muffler.

Figure 3: Existing Model (with Nozzle) Figure 4: Modified Model (with Nozzle)

METHODOLOGY All the 4 models were attached to testing rig one by one and operated at speed of 1500rpm for finite duration of time till steady state was achieved. Pressures (P1, P2, P3, P4, P5) and temperatures (T1, T2, T3, T4, T5) were noted down. Time required for consumption of 10 gm of fuel and manometric pressure head at orifice meter attached for the measurement of the air flow rate were also noted down. These readings were taken down at different loading condition i.e. 2kg, 4kg, 6kg, 8kg, 10kg and 12 kg. Morse test was also conducted on all these 4 models at all above mentioned loading conditions at said speed. Purpose of Morse test was to investigate I.P. of the engine which in turn helps in evaluation of mechanical efficiency. All the results obtained along with Heat balance sheet were subsequently tabulated to draw the conclusions. Material Fluid Properties Exhaust gas will be considered as an incompressible fluid operating at 230�280 0C. The material properties under these conditions are Table 1: Material Fluid Properties Material Density (kg/m3) Viscosity (Pa-s) Specific heat (J/kg-K) Thermal conductivity (W/m-K)

Air + Gasoline 1.0685 3.0927 x 10�5 1056.6434 0.0250

Boundary Conditions The engine speed was maintained at 1500 RPM and results were obtained at different load Conditions viz. 2kg, 4kg, 6k, 8kg and 12 kg. The atmospheric gauge pressure was assumed to be at 0. The flow through manifold was assumed to be steady state.


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K. S. Umesh, V. K. Pravin & K. Rajagopal

Experimental Set-up The test was conducted on 4 stroke 4 cylinder Engine of Maruti-Suzuki Wagon-R. Experimental set up consisted of: 

The engine & dynamometer fitted together on common channel frame

Fuel Consumption measuring unit & temperature measuring units

Exhaust gas Calorimeter

Orifice Meter Experimental set up shown in figure:

Figure 5: Experimental Set-up Temperatures were measured at 

Exhaust Gas inlet to the calorimeter

Exhaust gas outlet to calorimeter

Water inlet to calorimeter

Water outlet from Calorimeter

Water outlet from Engine Also pressure and temperatures were measured in header at points where bends are attached and in the exhaust.

Engine Specifications Table 2: Engine Specification Engine Make Calorific Value of Fuel (Gasoline) Specific Gravity of Fuel Bore and Stroke Swept Volume Compression Ratio Dynamometer Constant Diameter of Orifice Coefficient of Discharge of orifice

4 Stroke 4 Cylinder SI engine Maruti-Suzuki Wagon-R 45208 KJ/Kg-K 0.7 gm/cc 69.05 mm X 73.40 mm 1100 cc 7.2 :1 2000 29 mm 0.65


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Experimental Analysis of Optimal Geometry for Exhaust Manifold of Multi-Cylinder SI Engine for Optimum Performance

RESULTS Results obtained during the investigation of all 4 models after the calculations are enlisted in following tables. Qs and Qa specify swept volume and air intake respectively. Thus their ratio gives volumetric efficiency. Also morse test was conducted on engines to evaluate their Indicated power (I.P.). Brake power (B.P.) was experimentally determined using dynamometer. Thus Mechanical efficiency was also evaluated as ratio of B.P. to I.P. Velocity was calculated using continuity equation. These are instantaneous velocities of exhaust gas at above mentioned points. Table 3: Existing Model (Calculations) (1) Load (2) Speed (3) B.P. (kW) (4) Heat Equivalent (5) Time (t) (6) Fuel Consumption (7) Heat Supplied (8)Tw(outlet) (9) Tw (inlet) (10) Heat carried away (11) Water temp (inlet) (12) Water temp (outlet) (13) Flue gas temp (in) (14) Flue gas temp (out) (15) Heat capacity (16) Engine Exhaust temp. (17) Atmospheric temp (18)Heat gone with exhaust (19)Unaccounted loss (20) Swept Volume (21) Manometric Head (22) Air Consumption (23) Volumetric Efficiency (24) BSFC (25) Air Fuel Ratio (26) Morse test (no cut off) (27) Morse test (1st cut off) (28) Morse test (2nd cut off) (29) Morse test (3rd cut off) (30) Morse test (4th cut off) (31) I.P. (1st) (32) I.P. (2nd) (33) I.P. (3rd) (34) I.P. (4rd) (35) I.P. (36) Mechanical Efficiency (37) F.P. (38) Total flow rate (Vf + Va) (39) Flow rate per Cylinder (40) Exhaust Diameter (41) Exhaust Velocity (42) Back Pressure (43) Thermal Efficiency

Unit kg rpm KW Kj/min sec gm/min Kj/min o C o C Kj/min o C o C o C o C Kj/kgoC o C o C Kj/min Kj/min m3/s mm of H2O m3/s EXP kg/kW-hr kg kg kg kg kg KW KW KW KW KW KW m3/s m3/s m m/s mm of H2O

2 1500 1.119 67.14 17.09 35.108 1587.2 46 28 286.39 23 28 109 54 1.4464 303 24 403.55 830.09 0.0138 18 0.0074 53.764 0.3964 12.634 2 1.4 1.4 1.4 1.4 0.3357 0.3357 0.3357 0.3357 1.3428 83.333 0.2238 0.0074 0.0018 0.0525 0.8544 90 4.2302

4 1500 2.238 134.28 16.6 36.145 1634 74 30 700.07 23 30 152 58 1.1848 381 24 422.98 376.69 0.0138 16 0.007 50.69 0.1869 11.57 4 2.9 2.9 2.9 2.8 0.6155 0.6155 0.6155 0.6714 2.5178 88.889 0.2798 0.007 0.0017 0.0525 0.8055 131 8.2177

6 1500 3.357 201.42 15.81 37.951 1715.7 80 31 779.62 22 31 179 75 1.3769 403 24 521.84 212.8 0.0138 21 0.008 58.072 0.1427 12.624 6 4.3 4.3 4.3 4.3 0.9512 0.9512 0.9512 0.9512 3.8046 88.235 0.4476 0.008 0.002 0.0525 0.9228 169 11.74

8 1500 4.476 268.56 14.13 42.463 1919.7 83 32 811.44 22 32 198 95 1.5447 409 24 594.72 244.94 0.0138 26 0.0089 64.617 0.1191 12.554 8 5.9 5.8 5.8 5.8 1.175 1.2309 1.2309 1.2309 4.8677 91.954 0.3917 0.0089 0.0022 0.0525 1.0268 196 13.99

10 1500 5.595 335.7 14 42.857 1937.5 84 32 827.35 22 32 206 109 1.6403 401 24 618.38 156.05 0.0138 29 0.0094 68.243 0.1006 13.137 10 7.35 7.4 7.35 7.35 1.4827 1.4547 1.4827 1.4827 5.9027 94.787 0.3077 0.0094 0.0023 0.0525 1.0845 198 17.327

12 1500 6.714 402.84 13.31 45.079 2037.9 85 32 843.26 22 32 212 120 1.7294 385 24 624.32 167.51 0.0138 33 0.01 72.797 0.0895 13.323 12 8.7 8.7 8.6 8.7 1.8464 1.8464 1.9023 1.8464 7.4414 90.226 0.7274 0.01 0.0025 0.0525 1.1568 223 19.767


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K. S. Umesh, V. K. Pravin & K. Rajagopal

Table 4: Existing Model (Heat Balanced Sheet) Heat Balance Sheet Heat Supplied (total) Total Percentage (Supply) Heat Utilised Brake Power Percentage Heat carried by cooling H2O Percentage Heat carried by exhaust gas Percentage Unaccounted Heat loss Percentage Heat Utilised (total) Total Percentage Utilised

Unit Kj/min

Kj/min Kj/min Kj/min Kj/min Kj/min

1587.2 100

1634.02 100

1715.67 100

1919.66 100

1937.5 100

2038 100

67.14 4.2302 286.39 18.044 403.55 25.426 830.09 52.3 1587.2 100

134.28 8.21775 700.066 42.8431 422.985 25.8861 376.693 23.0531 1634.02 100

201.42 11.74 779.619 45.441 521.837 30.4159 212.797 12.4031 1715.67 100

268.56 13.99 811.441 42.27 594.717 30.9803 244.943 12.7597 1919.66 100

335.7 17.327 827.35 42.702 618.38 31.917 156.05 8.0544 1937.5 100

402.8 19.77 843.3 41.38 624.3 30.63 167.5 8.219 2038 100

8 1500 4.476 268.6 11.4 52.63 2379 63 29 541 21 29 171 95 1.675 340 21 534.3 1036 0.014 41 0.011 81.14 0.15 12.72 8 5.9 5.8 5.8 5.9 1.175 1.231 1.231 1.175 4.812 93.02 0.336 0.011 0.003 0.052

10 1500 5.595 335.7 11.2 53.57 2422 74 31 684.2 21 31 195 113 1.94 390 21 716 686 0.014 41 0.011 81.14 0.12 12.5 10 7.3 7.3 7.3 7.4 1.511 1.511 1.511 1.455 5.987 93.46 0.392 0.011 0.003 0.052

Table 5: Modified Model (Calculations) (1) Load (2) Speed (3) B.P. (kW) (4) Heat Equivalent (5) Time (t) (6) Fuel Consumption (7) Heat Supplied (8)Tw(outlet) (9) Tw (inlet) (10) Heat carried away (11) Water temp (inlet) (12) Water temp (outlet) (13) Flue gas temp (in) (14) Flue gas temp (out) (15) Heat capacity (16) Engine Exhaust temp. (17) Atmospheric temp (18)Heat gone with exhaust (19)Unaccounted Heat loss (20) Swept Volume (21) Manometric Head (22) Air Consumption (23) Volumetric Efficiency (24) BSFC (25) Air Fuel Ratio (26) Morse test (no cut off) (27) Morse test (1st cut off) (28) Morse test (2nd cut off) (29) Morse test (3rd cut off) (30) Morse test (4th cut off) (31) I.P. (1st) (32) I.P. (2nd) (33) I.P. (3rd) (34) I.P. (4rd) (35) I.P. (36) Mechanical Efficiency (37) F.P. (38) Total flow rate (Vf + Va) (39) Flow rate per Cylinder (40) Exhaust Diameter

Unit kg rpm KW Kj/min sec gm/min Kj/min o C o C Kj/min o C o C o C o C Kj/kgoC o C o C Kj/min Kj/min m3/s mm of H2O m3/s EXP kg/kW-hr kg kg kg kg kg KW KW KW KW KW KW m3/s m3/s m

2 1500 1.119 67.14 13.1 45.802 2070.6 36 26 159.11 22 26 104 61 1.4801 240 21 324.13 1520.2 0.0138 25 0.0087 63.362 0.4671 11.413 2 1.45 1.45 1.45 1.45 0.3077 0.3077 0.3077 0.3077 1.2309 90.909 0.1119 0.0087 0.0022 0.0525

4 1500 2.238 134.28 12.28 48.86 2208.9 42 27 238.66 22 27 123 71 1.5299 257 21 361.05 1474.9 0.0138 32 0.0099 71.686 0.2643 12.104 4 2.85 2.9 2.95 2.95 0.6434 0.6155 0.5875 0.5875 2.4338 91.954 0.1958 0.0099 0.0025 0.0525

6 1500 3.357 201.42 12.1 49.587 2241.7 50 27 365.94 21 27 144 77 1.4248 292 21 386.13 1288.2 0.0138 31 0.0097 70.557 0.1734 11.739 6 4.4 4.35 4.3 4.35 0.8952 0.9232 0.9512 0.9232 3.6927 90.909 0.3357 0.0097 0.0024 0.0525

12 1500 6.714 402.84 11 54.545 2465.9 76 30 731.89 21 30 201 118 1.7252 405 21 662.49 668.67 0.0138 36 0.0105 76.034 0.0934 11.5 12 8.7 8.7 8.7 8.7 1.8464 1.8464 1.8464 1.8464 7.3854 90.909 0.6714 0.0105 0.0026 0.0525


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Experimental Analysis of Optimal Geometry for Exhaust Manifold of Multi-Cylinder SI Engine for Optimum Performance

(41) Exhaust Velocity (42) Back Pressure (43) Thermal Efficiency

m/s mm of H2O

Table 5: Contd., 1.0069 1.1392 89 107 3.2425 6.0792

1.1212 147 8.9851

1.289 173 11.29

1.289 178 13.86

1.2083 210 16.336

Table 6: Existing Model (Heat Balanced Sheet) Heat Balance Sheet Heat Supplied (total) Total Percentage (Supply) Heat Utilised Brake Power Percentage Heat carried by cooling H2O Percentage Heat carried by exhaust gas Percentage Unaccounted Heat loss Percentage Heat Utilised (total) Total Percentage Utilised

Unit Kj/min

Kj/min Kj/min Kj/min Kj/min Kj/min

2070.6 100

2208.9 100

2241.7 100

2379.37 100

2421.86 100

2465.9 100

67.14 3.2425 159.11 7.6841 324.13 15.654 1520.2 73.419 2070.6 100

134.28 6.0792 238.66 10.805 361.05 16.345 1474.9 66.771 2208.9 100

201.42 8.9851 365.94 16.324 386.13 17.225 1288.2 57.466 2241.7 100

268.56 11.287 540.96 22.7355 534.261 22.4539 1035.59 43.5236 2379.37 100

335.7 13.8613 684.156 28.2492 715.977 29.5631 686.024 28.3264 2421.86 100

402.84 16.336 731.89 29.68 662.49 26.866 668.67 27.117 2465.9 100

Table 7: Existing Model with Nozzle (Calculations) (1) Load (2) Speed (3) B.P. (kW) (4) Heat Equivalent (5) Time (t) (6) Fuel Consumption (7) Heat Supplied (8)Tw(outlet) (9) Tw (inlet) (10) Heat carried away (11) Water temp (inlet) (12) Water temp (outlet) (13) Flue gas temp (in) (14) Flue gas temp (out) (15) Heat capacity (16) Engine Exhaust temp. (17) Atmospheric temp (18)Heat gone with exhaust (19)Unaccounted Heat loss (20) Swept Volume (21) Manometric Head (22) Air Consumption (23) Volumetric Efficiency (24) BSFC (25) Air Fuel Ratio (26) Morse test (no cut off) (27) Morse test (1st cut off) (28) Morse test (2nd cut off) (29) Morse test (3rd cut off) (30) Morse test (4th cut off) (31) I.P. (1st) (32) I.P. (2nd) (33) I.P. (3rd) (34) I.P. (4rd) (35) I.P.

Unit kg rpm KW Kj/min sec gm/min Kj/min o C o C Kj/min o C o C o C o C Kj/kgoC o C o C Kj/min Kj/min m3/s mm of H2O m3/s EXP kg/kW-hr kg kg kg kg kg KW KW KW KW KW

2 1500 1.119 67.14 18.38 32.644 1475.8 28 22 95.464 17 22 96 34 1.2831 217 20 252.77 1060.4 0.0138 15 0.0067 49.08 0.3618 12.404 2 1.4 1.45 1.45 1.4 0.3357 0.3077 0.3077 0.3357 1.2869

4 1500 2.238 134.28 17.54 34.2075 1546.45 48 24 381.854 16 24 133 37 1.32588 287 20 354.011 676.309 0.01375 18 0.00739 53.7645 0.19819 12.9666 4 2.85 2.9 2.85 2.85 0.64343 0.61545 0.64343 0.64343 2.54573

6 1500 3.357 201.42 17.47 34.345 1552.7 67 24 684.16 16 24 144 36 1.1786 307 20 338.25 328.83 0.0138 19 0.0076 55.238 0.1357 13.269 6 4.45 4.35 4.3 4.3 0.8672 0.9232 0.9512 0.9512 3.6927

8 1500 4.476 268.56 16.25 36.9231 1669.22 73 24 779.619 16 24 158 37 1.05194 301 20 295.595 325.444 0.01375 22 0.00817 59.4389 0.10956 13.2809 8 5.9 5.8 5.8 5.8 1.17495 1.2309 1.2309 1.2309 4.86765

10 1500 5.595 335.7 16.1 37.267 1684.8 73 24 779.62 15 24 150 38 1.2785 292 20 347.76 221.69 0.0138 22 0.0082 59.439 0.0876 13.158 10 7.3 7.3 7.3 7.3 1.5107 1.5107 1.5107 1.5107 6.0426

12 1500 6.714 402.84 15.3 39.2157 1772.86 76 24 827.351 15 24 156 39 1.22389 288 20 328.003 214.668 0.01375 28 0.00922 67.0561 0.0824 14.1069 12 8.7 8.7 8.7 8.7 1.84635 1.84635 1.84635 1.84635 7.3854


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K. S. Umesh, V. K. Pravin & K. Rajagopal

Table 7: Contd., 86.957 87.9121 KW 0.1679 0.30773 m3/s 0.0067 0.00739 m3/s 0.0017 0.00185 m 0.038 0.038 m/s 1.4876 1.62957 mm of H2O 112 140 4.5495 8.68309

(36) Mechanical Efficiency (37) F.P. (38) Total flow rate (Vf + Va) (39) Flow rate per Cylinder (40) Exhaust Diameter (41) Exhaust Velocity (42) Back Pressure (43) Thermal Efficiency

90.909 0.3357 0.0076 0.0019 0.038 1.6742 210 12.973

91.954 0.39165 0.00817 0.00204 0.038 1.80155 212 16.089

92.593 0.4476 0.0082 0.002 0.038 1.8016 224 19.926

90.9091 0.6714 0.00922 0.00231 0.038 2.03241 235 22.7226

Table 8: Existing Model with Nozzle (Heat Balance Sheet) Heat Balance Sheet Heat Supplied (total) Total Percentage (Supply) Heat Utilised Brake Power Percentage Heat carried by cooling H2O Percentage Heat carried by exhaust gas Percentage Unaccounted Heat loss Percentage Heat Utilised (total) Total Percentage Utilised

Unit Kj/min

Kj/min Kj/min Kj/min Kj/min Kj/min

1475.8 100

1546.5 100

1552.65 100

1669.22 100

1684.8 100

1772.9 100

67.14 4.5495 95.464 6.4687 252.77 17.128 1060.4 71.854 1475.8 100

134.28 8.6831 381.85 24.692 354.01 22.892 676.31 43.733 1546.5 100

201.42 12.9727 684.156 44.0637 338.248 21.7852 328.827 21.1784 1552.65 100

268.56 16.089 779.619 46.7057 295.595 17.7086 325.444 19.4968 1669.22 100

335.7 19.926 779.62 46.275 347.76 20.641 221.69 13.159 1684.8 100

402.84 22.723 827.35 46.668 328 18.501 214.67 12.109 1772.9 100

Table 9: Modified Model with Nozzle (Calculations) Column1 (1) Load (2) Speed (3) B.P. (kW) (4) Heat Equivalent (5) Time (t) (6) Fuel Consumption (7) Heat Supplied (8)Tw(outlet) (9) Tw (inlet) (10) Heat carried away (11) Water temp (inlet) (12) Water temp (outlet) (13) Flue gas temp (in) (14) Flue gas temp (out) (15) Heat capacity (16) Engine Exhaust temp. (17) Atmospheric temp (18)Heat gone with exhaust (19)Unaccounted Heat loss (20) Swept Volume (21) Manometric Head (22) Air Consumption (23) Volumetric Efficiency (24) BSFC (25) Air Fuel Ratio (26) Morse test (no cut off) (27) Morse test (1st cut off) (28) Morse test (2nd cut off) (29) Morse test (3rd cut off)

Column2 Unit kg rpm KW Kj/min sec gm/min Kj/min o C o C Kj/min o C o C o C o C Kj/kgoC o C o C Kj/min Kj/min m3/s mm of H2O m3/s EXP kg/kW-hr kg kg kg kg

Column3

Column4

Column5

Column6

Column7

Column8

2 1500 1.119 67.14 13.1 45.802 2070.6 36 26 159.11 22 26 104 61 1.4801 270 19 371.49 1472.9 0.0138 13 0.0063 45.691 0.3369 8.2301 2 1.45 1.45 1.45

4 1500 2.238 134.28 12.28 48.8599 2208.86 42 27 238.659 22 27 123 71 1.52987 287 19 410.004 1425.92 0.01375 15 0.00675 49.08 0.18092 8.28716 4 2.85 2.85 2.85

6 1500 3.357 201.42 12.1 49.5868 2241.72 50 27 365.944 21 27 144 77 1.42483 312 19 417.475 1256.88 0.01375 18 0.00739 53.7645 0.13213 8.94506 6 4.35 4.35 4.35

8 1500 4.476 268.56 11.4 52.6316 2379.37 63 29 540.96 21 29 171 95 1.6748 370 19 587.855 981.993 0.01375 20 0.00779 56.6727 0.10446 8.88345 8 5.9 5.8 5.8

10 1500 5.595 335.7 11.2 53.5714 2421.86 74 31 684.156 21 31 195 113 1.94032 420 19 778.067 623.934 0.01375 24 0.00854 62.0819 0.09154 9.56061 10 7.3 7.3 7.2

12 1500 6.714 402.84 11 54.5455 2465.89 76 30 731.888 21 30 201 118 1.72525 435 19 717.702 613.461 0.01375 30 0.00954 69.4096 0.08529 10.4982 12 8.8 8.7 8.7


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Experimental Analysis of Optimal Geometry for Exhaust Manifold of Multi-Cylinder SI Engine for Optimum Performance

(30) Morse test (4th cut off) (31) I.P. (1st) (32) I.P. (2nd) (33) I.P. (3rd) (34) I.P. (4rd) (35) I.P. (36) Mechanical Efficiency (37) F.P. (38) Total flow rate (Vf + Va) (39) Flow rate per Cylinder (40) Exhaust Diameter (41) Exhaust Velocity (42) Back Pressure (43) Thermal Efficiency

kg KW KW KW KW KW KW m3/s m3/s m m/s mm of H2O

Table 9: Contd., 1.45 2.85 0.3077 0.64343 0.3077 0.64343 0.3077 0.64343 0.3077 0.64343 1.2309 2.5737 90.909 86.9565 0.1119 0.3357 0.0063 0.00675 0.0016 0.00169 0.038 0.038 1.385 1.48768 109 135 3.2425 6.07915

4.35 0.92318 0.92318 0.92318 0.92318 3.6927 90.9091 0.3357 0.00739 0.00185 0.038 1.62965 186 8.98507

5.9 1.17495 1.2309 1.2309 1.17495 4.8117 93.0233 0.3357 0.00779 0.00195 0.038 1.7178 210 11.287

7.25 1.51065 1.51065 1.5666 1.53863 6.12653 91.3242 0.53153 0.00854 0.00213 0.038 1.88174 217 13.8613

8.8 1.7904 1.84635 1.84635 1.7904 7.2735 92.3077 0.5595 0.00955 0.00239 0.038 2.10382 224 16.3365

Table 10: Modified Model with Nozzle (Heat Balance Sheet) Heat Balance Sheet Heat Supplied (total) Total Percentage (Supply) Heat Utilised Brake Power Percentage Heat carried by cooling H2O Percentage Heat carried by exhaust gas Percentage Unaccounted Heat loss Percentage Heat Utilised (total) Total Percentage Utilised

Unit Kj/min

Kj/min Kj/min Kj/min Kj/min Kj/min

2070.6 100

2208.86 100

2241.72 100

2379.4 100

2421.86 100

2465.9 100

67.14 3.24255 159.106 7.68407 371.494 17.9414 1472.86 71.132 2070.6 100

134.28 6.07915 238.659 10.8046 410.004 18.5618 1425.92 64.5544 2208.86 100

201.42 8.98507 365.944 16.3242 417.475 18.623 1256.88 56.0677 2241.72 100

268.56 11.287 540.96 22.735 587.85 24.706 981.99 41.271 2379.4 100

335.7 13.8613 684.156 28.2492 778.067 32.1269 623.934 25.7626 2421.86 100

402.84 16.336 731.89 29.68 717.7 29.105 613.46 24.878 2465.9 100

The results obtained through the experiment are plotted with suitable scale to emphasize the findings of the work.

Figure 6: Volumetric Efficiency vs Load

Figure 7: Mechanical Efficiency vs Load


20

K. S. Umesh, V. K. Pravin & K. Rajagopal

Figure 8: B.S.F.C. vs Load

Figure 9: Exhaust Velocity vs Load

Figure 10: Back Pressure vs Load

Figure 11: Thermal Efficiency vs Load

CONCLUSIONS From nature of all the graphs obtained as a result of observations made it is quite obvious that no manifold


21

Experimental Analysis of Optimal Geometry for Exhaust Manifold of Multi-Cylinder SI Engine for Optimum Performance

geometry is perfect for all kind of purposes. It can be easily observed that a model which gives highest volumetric efficiency essentially gives maximum BSFC i.e. minimum thermal efficiency. Thus it means that design that produces more power per cycle also consumes more fuel per unit time. This in turn result in dilemma in choice of best exhaust manifold geometry for given application. Following Game matrix obtained from above graphs leads to optimal solution. Table 11 Model 1 Model 2 Model 3 Model 4

Recreational Purpose Average Best suited Average Not Suitable

Both Good Enough Average Good Enough Average

Commercial Purpose Average Not suitable Average Best Suited

Acceptable Design :- (a) Best Suited (b) Good Enough

REFERENCES 1.

M.B. Beardsley et al.,Thermal Barrier Coatings for Low Emission, High Efficiency Diesel Engine Applications” SAE Technical Paper 1999-01-2255.

2.

Rajesh Biniwale , N.K. Labhsetwar, R.Kumar and M.Z.Hasan, “A non-noble metal based catalytic converter for two strokes, two-wheeler applications”, SAE Paper No. 2001011303, 2001.

3.

G. Muramatsu, A. Abe, M. Furuyama, “Catalytic Reduction of Nox in Diesel Exhaust”, SAE 930135, 1993.

4.

John B. Heywood, Internal Combustion Engine Fundamentals (Tata McGrah Hill).

5.

Nitin K. Labhsetwar, A. Watanabe and T. Mitsuhashi, “Possibilities of the application of catalyst technologies for the control of particulate emission for diesel vehicles”, SAE Transaction 2001, paper no. 2001280044.

6.

PL.S. Muthaiah, Dr.M. Senthil Kumar, Dr. S. Sendilvelan “CFD Analysis of catalytic converter to reduce particulate matter and achieve limited back pressure in diesel engine”, Global journal of researches in engineering A: Classification (FOR) 091304,091399, Vol.10 Issue 5 (Ver1.0) October 2010.

7.

P.R.Kamble and S.S. Ingle “Copper Plate Catalytic Converter: An Emission Control Technique”, SAE Number 2008-28-0104.

8.

Eberhard Jacob, Rheinhard Lammermann, Andreas Pappenherimer, and Diether Rothe Exhaust Gas After treatment System for Euro 4: Heavy Duty Engines – MTZ 6/2005.

9.

Jacobs, T., Chatterjee, S., Conway, R., Walker, A., Kramer, J. and K. Mueller-Haas, Development Of a Partial Filter Technology for Hdd Retrofit, Sae Technical Paper 2006-01-0213.

10. C. Lahousse, B. Kern,H. Hadrane and L. Faillon, “Backpressure Characteristics of Modern Three-way Catalysts”, Benefit on Engine Performance, SAE Paper No. 2006011062,2006 SAE World Congress, Detroit, Michigan , April 36, 2006.



2 experimental analysis full