POST TEST - AREA 1

The part of an internal combustion engine that converts reciprocating motion to rotary motion is:

• Piston

• Camshaft

• Crankshaft

• Flywheel

What is the average oxygen content of air by volume?

• 21%

• 32%

• 15%

• 25%

The correct firing interval of a 4-stroke, 3-cylinder engine is:

• 120°

• 180°

• 240°

• 360°

The thermal efficiency of most diesel engines is approximately:

• 25%

• 40%

• 60%

• 85%

(Computation) A tractor exerts a draft of 12 kN at 4 km/h. Compute the drawbar power.

• 8.0 kW

• 9.2 kW

• 10.5 kW

• 12.5 kW

(Computation) A four-cylinder diesel engine has bore 100 mm and stroke 120 mm. Compute displacement.

• 2.95 L

• 3.50 L

• 3.77 L

• 4.20 L

A tractor engine develops a brake horsepower of 45 hp. If mechanical efficiency is 80%, what is the indicated horsepower?

• 48 hp

• 52 hp

• 56.25 hp

• 60 hp

(Computation) A 35-hp tractor operates 6 hrs/day with specific fuel consumption 0.25 L/hp·hr. Daily fuel used:

• 45 L

• 52.5 L

• 55 L

• 60 L

(Computation) A hydropower turbine delivers 50 kW under 12 m head at 80% efficiency. Compute flow rate (ρ=1000 kg/m³, g=9.81 m/s²).

• 0.42 m³/s

• 0.53 m³/s

• 0.61 m³/s

• 0.75 m³/s

A gasoline engine has clearance volume 120 cc and total volume 720 cc. What is compression ratio?

• 5:1

• 6:1

• 7:1

• 8:1