Question

A single-cylinder, four-stroke cycle CI engine with 12.9-cm bore and 18.0-cm stroke, operating at 800 RPM, uses 0.113 kg of fuel in four minutes while developing a torque of76 N-m. Calculate:

(a) Brake specific fuel consumption. [grnlkW-hr]
(b) Brake mean effective pressure. [kpa]
(c) Brake power. [kW]
(d) Specific power. [kW/cm²]
(e) Output per displacement. [kW/L]
(f) Specific volume. [L/kW]

Answer 1

To calculate the values, we can use the following formulas:

(a) Brake Specific Fuel Consumption (BSFC):

BSFC = Fuel consumption (kg) / Brake Power (kW)

(b) Brake Mean Effective Pressure (BMEP):

BMEP = (2 x π x Torque (N-m) x 60) / (Engine displacement (cm³) x RPM)

(c) Brake Power:

Brake Power = (2 x π x Torque (N-m) x RPM) / 60

(d) Specific Power:

Specific Power = Brake Power (kW) / Engine displacement (cm³)

(e) Output per Displacement:

Output per Displacement = Brake Power (kW) / Engine displacement (L)

(f) Specific Volume:

Specific Volume = 1 / Output per Displacement

Given:

Bore = 12.9 cm

Stroke = 18.0 cm

RPM = 800

Fuel consumption = 0.113 kg

Torque = 76 N-m

(a) First, we need to convert fuel consumption to grnlkW-hr:

Fuel consumption = 0.113 kg x 1000 g/kg x 1 lb/453.592 g x 1 gal/6.305 lb x 3.78541 L/g = 0.2518 gal

BSFC = 0.2518 gal / (Brake Power (kW) x 0.25 hr)

(b) Engine displacement:

Engine displacement = (π/4) x (Bore (cm)²) x Stroke (cm) = (3.14159/4) x (12.9 cm)² x 18.0 cm = 10486.6 cm³

BMEP = (2 x π x 76 N-m x 60) / (10486.6 cm³ x 800 RPM)

(c) Brake Power:

Brake Power = (2 x π x 76 N-m x 800 RPM) / 60

(d) Specific Power:

Specific Power = Brake Power (kW) / 10486.6 cm³

(e) Output per Displacement:

Output per Displacement = Brake Power (kW) / 10.4866 L

(f) Specific Volume:

Specific Volume = 1 / (Brake Power (kW) / 10.4866 L)

Now, we can substitute the given values into the formulas to calculate the respective values.

Step-by-step explanation:

Answer 2

To calculate the brake specific fuel consumption, brake mean effective pressure, brake power, specific power, output per displacement, and specific volume of a single-cylinder, four-stroke cycle CI engine, various formulas are used. These formulas involve the values provided, such as fuel consumption, torque, engine speed, bore, and stroke.

Step-by-step explanation:

To calculate the brake specific fuel consumption (BSFC), we can use the formula:

BSFC = (Fuel consumption / Brake power) * 3600

First, we need to calculate the fuel consumption:

Fuel consumption = 0.113 kg / 4 minutes = 0.02825 kg/min

To calculate the brake power, we can use the formula:

Brake power = Torque * Engine speed / 2π

Brake power = 76 N-m * 800 RPM / 2π

Now we can plug in the values into the formula for BSFC:

BSFC = (0.02825 kg/min / Brake power) * 3600

For part (b), the formula for Brake mean effective pressure (BMEP) is:

BMEP = (Brake power * 1000) / (Displacement * Engine speed)

We can plug in the values to calculate BMEP.

For part (c), Brake power is already calculated in part (a).

For part (d), Specific power can be calculated using the formula:

Specific power = Brake power / Displacement

For part (e), Output per displacement can be calculated using the formula:

Output per displacement = Brake power / Displacement

For part (f), Specific volume can be calculated using the formula:

Specific volume = 1 / Output per displacement