1.
Torque, T =
9.81 x W x R Effective Nm.

Where R Effective = (D + d)/2 m,

W (Load) = ( S1 S2) Kg.

2.
Brake Power, B
P = ( 2

**π**N T ) / 60, 000 KW
Where N = rpm,

T =
Torque Nm,

3.
Indicated Power, I P = n ( Pm x L Stroke x
A x N’) / 60,000 KW

Where Pm = Mean Effective Pressure N/ m

^{2},
L Stroke = Stroke m,

A
(Cross Section of the Cylinder) = (πD

^{2}_{Bore})/ 4 m^{2},
N’
(Number of Power Strokes/ min.)

= N/ 2
per min. (For Four Stroke Engine)

=N per
min. (For Two Stroke Engine)

N = rpm,
and

n =
Number of Cylinders.

4.
Fuel Consumption, m f = ( 50
ml x 10

^{6 }x**ρ**Fuel ) / ( t ) Kg/Sec.
Here; 1 ml = 10

^{-3 }liters, and 1000 liters = 1m^{3}
So 1 ml = 10

^{-6 }m^{3}
5.
Brake Mean Effective Pressure, BMEP = (BP x 60,000)/ ( L Stroke
x A x N’) N/ m2

Where L Stroke = Stroke m,

A
(Cross Section of the Cylinder) = (π D

^{2}_{Bore})/4 m^{2},
N’
(Number of Power Strokes/ min.)

= N/ 2
per min. (For Four Stroke Engine.)

= N per
min. (For Two Stroke Engine)

N = speed
in rpm.

6.
Brake Specific Fuel Consumption, BSFC = ( mf x 3600 ) / BP Kg/ KW
. hr

7.
Indicated Specific Fuel Consumption, ISFC = ( mf x 3600 ) / IP Kg/ KW
.hr

8.
Indicated Thermal Efficiency,

**η**Indicated Thermal = ( IP x 100 ) / (mf x C.V. )%
9.
Brake Thermal Efficiency,

**η**Brake Thermal = ( B P x 100 ) / (m_{f}x C.V. ) %
10. Mass of the Air, m Air = C

_{d }Ao √2 g Δh**ρ**Air**ρ**Water Kg/ Sec ;
Where Cd ( Coefficient of Discharge ) = 0.6,

ρ

_{Air}= ( Pa x 102 ) / ( R x Ta ) Kg/m^{3}
Ao (
Area of Orifice ) = (π do

^{2})/ 4 m^{2},
Pa =
1.01325 Bar,

R =
0.287 KJ/ Kg K .

Ta = (
ta + 273 ) K,

ta =
Ambient Temperature O C

11. Air Fuel Ratio, A/F
= ( m Air / m

_{f}) Kg/ Kg of Fuel
12. Volumetric
Efficiency, η Volumetric
= ( VAir x
100 )/ Vs %

Where VAir ( Volume of air inhaled/ Sec.) = ( m Air / ρ Air ) m3/ Sec.

Vs ( Swept Volume/ Sec.) = n . ( L Stroke
. A.. N’ )/ 60 m3/ Sec.,

And Volume of fuel is Neglected (Based on free air
conditions),

A (Cross Section of the Cylinder) = (π D

^{2}Bore)/ 4 m^{2},
L Stroke = Stroke in m,

N’ (Number of Power Strokes/ min.)

= N/ 2
per min. (For Four Stroke Engine)

= N per
min (For Two Stroke Engine)

N = speed in rpm., and n = Number of Cylinders.

13.
Mechanical Efficiency, η

Where:

Commonly BSFC is expressed in units of grams per kilowatt-hour (g/(kW·h)). The conversion factor is as follows:

_{mechanical }= BP / IP## The BSFC calculation (in metric units) (Wikipedia)

To calculate this rate, use the formulaWhere:

*r*is the fuel consumption rate in grams per second (g·s^{-1})*P*is the power produced in watts where*P*= τω

- ω is the engine speed in radians per second (rad·s
^{-1}) - τ is the engine torque in newton meters (N·m)

- ω is the engine speed in radians per second (rad·s

^{−1})

Commonly BSFC is expressed in units of grams per kilowatt-hour (g/(kW·h)). The conversion factor is as follows:

- BSFC [g/(kW·h)] = BSFC [g/J]×(3.6×10
^{6})

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