Basic Mechanical Engineering (3110006)

BE | Semester-1   Winter-2019 | 03-01-2020

Q4) (c)

The following readings were observed during a test on Two Stroke Single Cylinder Diesel engine:
Bore = 22 cm Stoke = 28 cm Speed = 350 rpm Net brake load = 65 kg Effective brake drum diameter = 100 cm Mean Effective Pressure = 3 bar Fuel consumption = 4 kg/h Calorific value of fuel = 43 MJ. 
Calculate: (1) Indicated Power (2) Brake Power (3) Mechanical Efficiency (4) Brake thermal Efficiency

Given data d = 22 cm = 0.22 m
l = 28 cm = 0.28 m
N = 350 rpm
Wnet = 65 kg
Deff = 100 cm = 1 m
Reff= 0.5 m
pm = 3 bar = 300 kPa
mf = 4 kg/Hr
CV = 43 MJ = 43000 kJ

To Find : IP = ?, BP = ?, ηm = ?, ηbth = ? 

Now,

IP = pm l A N60

IP = 300 × 0.28 × π4 0.22 2 × 35060

IP = 18.626 kW 

Now,

BP = 2π N T60

BP = 2π N Wnet Reff60

BP = 2π × 350 × 65 × 9.81 × 0.560

BP = 11.685 kW


Now,

ηm = BPIP

ηm =  11.685 18.626

ηm = 0.6273

ηm = 62.73 %


Now,

ηbth = BP mf 3600  × CV  

ηbth = 11.685 4 3600  × 43000  

ηbth = 0.2445

ηbth = 24.45 %