Assignment 4

1.Compare SI vs CI and list down differences (assignment no 2-SI)

s.I engine
C.I engine

• In S.I engine there is a sapark plug to ignite the air/fuel mixture, but in case of C.I engine there is no saprk plug the air/fuel ignition occured due to high temperature and pressure.
• In S.I engine the fuel was delivered at either in inlet valve or in direct cylinder , but in C.I engine the fuel only was delivered directly to the cylinder.
• The power and torque profuced by the c.I engine was more than the S.I engine.
• The BSFC range of C.I was lesser than the S.I.
• Fuel flow rate of C.I engine was greater than the S.I engine.
• A/f ratio was also greater than the S.I engine

2.Comments on following parameters

• BSFC

The BSFC range for the above C.I engine model at 3600rpm is 238.2 g/Kw-h.

• Exhaust Temperature

The the exhaust temperature of the C.I engine model at 3600rpm is 1350k-950k.

• A/F ratios

The the Air/Fuel rate of the C.I engine model at 3600rpm is 20.78

3.Change MFB 50 and observe impact on performance

The MFB50 rates were changed and the engine was ran for the same 3600rpm the following results were obtained.

MFB 50	25	30	35	40
BSFC g/Kw-h	221	229	238	249
A/F ratio	20.77	20.77	20.78	20.78
Exhaust temp k	990	1015	1039	1063
power hp	39	37	36	34
torque N-m	103	100	93	91

pressure plot for different MFB 50.

MFB 50	pressure bar
25	136
30	123
35	117
40	113

temperature plot for different MFB 50.

MFB 50	temperature k
25	2169
30	2100
35	2042
40	1993

Conclusion:-

The given C.I engine example model was simulated and the required results had been pasted.

The comparision of S.I and C.I engine was done.