# Farm Machinery Questions and Answers – 4-Stroke Engine Vs. 2-Stroke Engine

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This set of Farm Machinery Multiple Choice Questions & Answers (MCQs) focuses on “4-Stroke Engine Vs. 2-Stroke Engine”.

1. Which is the third port, apart from exhaust and suction ports used in two-stroke engine?
a) Transfer port
b) Transport valve
c) Top dead centre
d) Bottom dead centre

Explanation: When the piston moves in the cylinder it covers two of the ports, the exhaust port and the transfer port, which are exactly opposite to each other which traps a charge of fresh mixture in the cylinder.

2. Cooling system of a 6.8 KW diesel engine at full load will remove heat at a rate of ________
a) 1.63 calories/min
b) 6.80 calories/min
c) 97.6 calories/min
d) 408 calories/min

Explanation: $$\frac{6.3*10^3*60}{4.2}$$
=97.6*103 calories/min
=97.6 k calories/min.

3. What is the quantity of water which is to be circulated through the radiator, if diesel tractor developed 80 KW with coolant temperature difference 5.5° C?
a) 9.44 L/s
b) 10.01 L/s
c) 7.44 L/s
d) 8.44 L/s

Explanation: Q=A.V.Ma.Ca.∆ta
Q=80*0.58*0.161
Q=7.44 L/s.
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4. What is the viscosity index for an oil having viscosity = 100s at 38°C? (L=137.9; H=107.1)
a) 132.38
b) 285.38
c) 120.06
d) 122.72

Explanation: V.I. = $$\frac{L-U}{L+U}$$*100
= $$\frac{137.9-100}{137.9-107.1}$$*100
= 122.72.

5. Which of the following is not a method of supplying fuel to the jet of the carburettor?
a) Suction method
b) Throttle system
c) Overflow method
d) Float valve method

Explanation: Throttle system is one of the classifications of the governor system. It consists in controlling the amount of fuel mixture during suction stroke and thereby changing the explosion intensity in the cylinder.

6. Which of the following is not a feature of diesel engine?
a) Engine has compression ratio 14:1 to 22:1
b) The control by hand lever or pedal lever is easy
c) Ignition takes place due to heat of compression only
d) During compression stroke, the engine attains high pressure ranging from 30 to 45 kg/cm2

Explanation: Hand lever or pedal lever is a part of clutch, which is a device used to connect and disconnect the tractor engine from the transmission gears and drive wheels.

7. Which of the following stages is the last stage of the combustion process in diesel engine?
a) Period of rapid pressure rise and heat transmission
b) Period of after burn
c) Period of direct burning of later injected fuel
d) Delay period before ignition

Explanation: In the period of after burn, fuel injection stops and fuel which has failed to burn till this period, burn during this stage.

8. A diesel tractor consumes 5 litres per hour of fuel whose density is 0.836 kg per litre. The heating value of the fuel is 45.4 MJkg-1. If the thermal efficiency of the engine is 0.30, the transmission efficiency is 0.90 and the tractive efficiency is 0.75, the drawbar power of the tractor will be __________
a) 10.54 KW
b) 13.18 KW
c) 18.98 KW
d) 39.53 KW

Explanation: Thermal efficiency, η = $$\frac{Brake\, power}{Fuel\, consumption*Density}$$*100
BP = $$\frac{FC*CV*\eta}{100}$$
BP = $$\frac{5*10^{-3}*0.836}{3600}*\frac{45.4*10^6*30}{100}$$
BP = 15.814 KW
DP of the tractor = 15.814*0.90*0.75
= 10.67KW.

Sanfoundry Global Education & Learning Series – Farm Machinery.