Explore Tutorial No.1 -CI Final
Title:Explore Tutorial No 1- CI final
Objective: 1.Compare SI vs CI and list down differences
2. Comments on following parameters
BSFC
Exhaust Temperature
A/F ratios
3.Change MFB 50 and observe impact on performance
Theory:
1.Compare SI vs CI and list down differences
| Sr.No | SI Engine | CI Engine |
| 1 | Fuel injected in intake port | Fuel injected in combustion cylinder |
| 2 | Stoichiometric Ratio maintain 14.5:1 | Stoichiometric Ratio vary |
| 3 |
Intial state provide in cylinder 2. Temprature =300k |
Intial state provide in cylinder 2. Temprature =350k |
| 4 |
lower bore & stroke length 1. Bore=86mm 2. Stroke=86.07mm 3. Connecting rod length=175mm |
Higher bore & stroke length 1. Bore=86mm 2. Stroke=86.07mm 3.Connecting rod length=220mm |
| 5 |
Lower compression ratio 9.5:1 |
Higher compression ratio 16.5:1 |
| 6 |
Spark plug uses for burn the fuel |
Fuel injector uses for fuel injection |
CI Engine Model
SI Engine Model
CI engine geometery
CI Engine SI Engine
Comparison of Single cylinder SI & CI Engine parameters
1.Brake power generated by CI engine is higher 36.3Kw due to higher compression ratio
2.Brake Torque generated by CI engine is higher 96.2N-m due to higher compression ratio
3. BSFC is lower by CI Engine 238.2g/kw-h due to higher thermal efficiency & CR
4. A/F Ratio is higher by CI Engine is 20.78 (lean mixture)
SI Engine CI Engine
1. Exhaust Temprature is lower by CI Engine is 1039k its due to higher A/F ratio
2. Higher NOx emission 1110ppm by CI Engine due to higher C.R
3 Higher CO emission 51474ppm by SI engine due to lower A/F ratio
4. higher HC 0.16ppm by SI Engine due to more carbon content in fuel
SI Engine CI Engine
1. Higher IMEP by CI Engine is 17.5 bar but higher friction losess
2. Higher Torque by CI Engine is 96.2 N-m but higher friction losess
3. Change MFB50 & Observe the impact on performance
for analyze the non-predictive combustion we give input as burn rate profile , but in that there is important parameter is Main duration as it vary its affected on the engine performance.so, vary MFB50 by 22, 33,44 & analyze the performance
Comparison of Main Duration
BP got by 22 main duration is higher 39.5kw
Input Burn Rate profile for Non-Predictive combustion
for vary the MFB50 , there is vary the Main duration 22,33, 44. So, it's observed that if we reduce main duration its observed that within less crank angle maximum fuel is burned.
Engine cylinde pressure
from above plot its obseved that as we reduce the main duration , there is high pressure is generated within less crank angle, so maximum fuel is burnt in less duration. so, 22 main duration generated high pressure. so, for 22 main duration higher Brake power generated 39.5 kw & higher pressure also.
Engine cylinder Maximum Temprature
due to less (22) main duration maximum fuel is bunt within crank angle , so maximum pressure generated, which result in higher inclyinder temprature.
NOx emission
from above graph its obseved that, for (22) main duration maximum fuel us burnt , so high pressure generated its result in higher temprature. so, in Diesel engine NO emission is generated due to higher incylinder temprature , so you can see for 22 main duration higher Nox emission is 2984ppm.
Conclusion
1. Understand the diffrence between SI & CI Engine model
2. Compare engine perfroamance parameters for SI & CI engine model
3. Vary the MFB50 (mass fuel burned) by use of main duration , as less the main duration higher pressure is generated which result in higher temprautre & higher NOx emission but there is higher Brake Power also.