I.C. Engines MCQs

A mixture with the exact chemical balanceA mixture with excess airA fuel-rich mixture used during idlingA fuel-rich mixture applied under heavy loadsThe ratio employed at maximum rated conditions

6.Which lubricant oil has the highest viscosity among the following options?

7.What component regulates the air-to-fuel mixture in petrol engines?

8.What does the pour point of fuel oil refer to?

The lowest temperature at which the oil releases enough flammable vapors to ignite briefly upon exposure to a flameThe temperature at which the oil begins to solidify or thickenThe temperature at which the oil ignites spontaneously without any external ignition sourceThe temperature corresponding to 90% distillation, when most of the oil has evaporatedThe temperature at which the oil flows freely without resistance

9.What is the approximate air-to-fuel ratio in a petrol engine that yields the highest power output in vehicles?

10.What is the typical air-fuel ratio for a petrol engine when it is idling?

11.Among the following, which liquid fuel is the lightest and most prone to evaporation?

12.By how much can the power output of a four-stroke diesel engine increase when a supercharger is installed?

13.What does the mean effective pressure derived from an engine indicator represent?

The highest pressure reachedThe lowest pressure recordedThe pressure at a specific momentThe pressure of the exhaust gasesThe average pressure over the cycle

14.In a standard medium-speed four-stroke diesel engine, when does the exhaust valve typically open and close?

The exhaust valve opens 35° before bottom dead center and closes 20° after top dead center.The exhaust valve opens exactly at bottom dead center and closes at top dead center.The exhaust valve opens shortly after bottom dead center and closes just prior to top dead center.The exhaust valve timings can vary and open and close at any point.None of the statements above are accurate.

15.In which type of engine is supercharging crucial?

16.What is the primary purpose of supercharging an engine?

17.In a 4-stroke petrol engine, the real volume of fresh air-fuel mixture admitted is usually:

the same as the stroke volumeequal to the sum of stroke and clearance volumessmaller than the stroke volumegreater than the stroke volumelarger than the total cylinder volume

18.In a petrol engine equipped with a suction carburettor, how does the fuel-to-air ratio change when using a dirty air filter compared to a clean one?

19.Why is an excessive amount of sulfur in diesel fuel considered problematic?

Leads to wear on piston rings and cylindersCauses hard deposits to develop on piston skirtsResults in sludge accumulation within the engine crankcaseTriggers engine knocking or detonationProduces corrosive acidic compounds

20.How does the size of an engine's intake valve compare to that of its exhaust valve?

Larger than the exhaust valveSmaller than the exhaust valveEqual in size to the exhaust valveVaries based on the engine's capacityDepends on the specific engine design

I.C. Engines MCQs

About this subject

1.Where is the combustion chamber situated in an opposed piston diesel engine?

2.In a naturally aspirated diesel engine, what component delivers the air to the engine?

3.In the crankcase scavenging technique, what generates the air pressure required for the process?

4.In loop scavenging, how is the piston crown typically shaped?

5.What does a stoichiometric air-fuel ratio represent?