For an initial analysis of a SI engine, the basic Otto cycle can be used. The following data...

Question

For an initial analysis of a SI engine, the basic Otto cycle can be used. The following data applies:
Ambient pressure and temperature, 101 kPa, 310 K; Swept (displacement) volume: 3000 cm3;
Stroke-to-bore ratio (S/B): 1:1;
Design, 6 cylinder, 4 stroke, compression ratio 9.5:1; Design speed range, 1000 to 5000 RPM;
Pressure and temperature in the cylinder at the start of compression at wide open throttle (WOT) at 2400 RPM: 95 kPa, 60oC;
Air to fuel ratio 15.5:1;
Heating value (HV) of the fuel 44 MJ/kg.

Find the bore size and stroke length of thisengine;

-4

Calculatethemass ofairand mass of fuel percylinderpercycle(m&air=4.6688x10kg);

Calculate the heat input per kg of mixture per cycle, qH XXXXXXXXXX7kJ/kg)
Using an isentropic index of 1.4 for cold air and a value of R of 0.287kJ/kg-K, determine the pressure and temperature conditions at each point in thecycle;
Calculate the engine thermal efficiency, specific net work, the engine net work output per cylinder per cycle, the engine power output, and the mean effective pressure(59%, 1583 kJ/kg, XXXXXXXXXXkJ/cylinder/cycle, 94.4 kW, 1573.4kPa).

Assignment 2
(Red words are correct result)
A single-cylinder four-stroke compression ignition (CI) engine with 12.9 cm bore and

cm stroke, operating at 2000 RPM, uses 0.311 kg of fuel in four minutes while developing a torque of 90 N-m. The engine compression ratio is 18:1 andmechanical efficiency is 85%.Calculate

engine displacement in litre and m3(2.3526L, 0.0023526m3).
clearance volume (0.13839L).
brake power in kW (18.85).
indicated power in kW(22.18).
friction power inkW.
fuel mass flow rate ing/s.
brake specific fuel consumption (bsfc) in g/kW-h(247.48).
brake mean effective pressure (BMEP) in kPa(480.74).
indicative mean effective pressure (IMEP) in kPa(565.58).
friction mean effective pressure (FMEP) in kPa(84.84).

Assignment 3

005_cbcva5o-ipwqft3e.docx

David · Accepted Answer

Assignment-1 
The given data, 
The ambient pressure and temperature, 
101kPa, 310 K  
The displacement volume, 
33000 cm  
Stroke to bore ratio, 
1 : 1  
The speed range, 
1000, 5000 RPM  
Heating value of the fuel, 
44 MJ/kg  
1. 
Apply the formula for bore diameter, 
Bore
3
Bore
Engine displacement
Stroke number of cylinders
3000 cm
11.18 cm
4 6
D
D


 

 
Stroke length for the cylinder, 
Engine displacement
Stroke length
Bore Bore 0.7854 No. of cylinder
3000
Stroke length 4.72 cm
11.8 11.8 0.7854 6

  
 
  
 
 
 
2. 
First calculate the clearance volume, 
1
2
3
0.003
9.5
8.5 0.003
350 cm
c d c
c
c c
c
c
V V VV
r
V V V
V
V
 
   


 
Apply the ideal gas equation, 
1 1
1
101 0.00335
0.00380 kg
0.287 310
m
PV
m
RT

  

 
Here mm is the mass of mixed gas. and 1 d cV V V  . 
Now, find the pressure and temperature, 
1.35
2 1
1 0.35 0
2 1
32
2
2
( ) 101 (9.5) 2109.8 kPa
(r ) 310 (8.6) 658.3 C
0.00380 0.287 931.3
0.0004814 m
2109.8
k
c
k
c
P P r
T T
mRT
V
P

   
   
 
  

Now, 
Mass of air, mass of fuel,  
15.5
16.5
15.5
0.00380 0.00356 kg
16.5
a m
a
m m
m
 
  
 
And, 
1
0.00380 0.0002303 kg
16.5
fm     
3. 
Calculate the heat input per cycle, 
in 3 2
3
0
3
( )
0.0002303 44000 (1) 0.00380 0.821 ( 931.3)
47825.33 K 4179.3 C
f HV c m v
in
Q m Q m c T T
Q T
T
  
      
 
 
And,  33 2 0.0004814 mV V   
So, 
2 3
3
2
2109.8 4179.3
9467.9 kPa
931.3
P T
P
T

    
Now, find the final temperature, pressure, and volume; 
1 0
4 3 0.35
4 3 1.35
34
4
4
1
(1 / r ) 4179 1601 C
15.5
1
(1 / r ) 9467 234 kPa
15.5
0.000380 0.

For an initial analysis of a SI engine, the basic Otto cycle can be used. The following data applies: Ambient pressure and temperature, 101 kPa, 310 K; Swept (displacement) volume: 3000 cm3;...

Solution

Answer To This Question Is Available To Download

Related Questions & Answers

Submit New Assignment