ABE TUTORIALS

AGRICULTURAL AND BIOSYSTEMS ENGINEERING

PROBLEM:
A FOUR-STROKE, FOUR-CYLINDER DIESEL ENGINE YIELDED THE FOLLOWING DATA DURING A ONE-HOUR DYNAMOMETER TEST: FUEL USED (40.91 KG), RPM (1200), DYNAMOMETER READING (113.64 KG), DYNAMOMETER ARM (61 CM), SG OF FUEL (0.8), BORE (15.24 CM) X STROKE (20.32 CM), HEATING VALUE (41.77 MJ/KG), AND COMPRESSION RATIO (22).

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1. The brake power:

a. 13.58 kW | b. 85 kW | c. 42.5 kW | d. 1534 kW | e. nota

View Solution

Torque (T) = Force × Arm = (113.64 kg × 9.81) × 0.61 m ≈ 680 Nm
Brake Power = (2 × π × N × T) / 60,000
BP = (2 × 3.1416 × 1200 × 680) / 60,000 ≈ 85.45 kW

Result: b. 85 kW

2. The specific fuel consumption in liters/kW-hr:

a. 0.845 | b. 0.1327 | c. 1.689 | d. 0.6032 | e. nota

View Solution

Fuel Volume = 40.91 kg / 0.8 SG = 51.1375 Liters
SFC = Total Liters / (BP × Time)
SFC = 51.1375 / (85.45 × 1) ≈ 0.598 L/kW-hr

Result: d. 0.6032 (closest match)

3. The brake mean effective pressure in kg/cm²:

a. 2.89 | b. 5.85 | c. .07 | d. .634 | e. nota

View Solution

Total Displacement = 4 cylinders × [π/4 × (15.24)² × 20.32] ≈ 14,826 cm³
BMEP = (BP × 60) / (Displacement × [RPM/2])
Calculated BMEP ≈ 5.88 kg/cm²

Result: b. 5.85

4. The clearance volume in cc:

a. 22.12 | b. 196.6 | c. 44.25 | d. 177 | e. nota

View Solution

Displacement per cyl (Vd) = 3706.67 cc
Vc = Vd / (Compression Ratio - 1)
Vc = 3706.67 / (22 - 1) = 3706.67 / 21 ≈ 176.5 cc

Result: d. 177