WorksheetsCPM Board Exam: Combustion Machines
Total questions: 30
Worksheet time: 15mins
What is the main function of a combustion engine?
Compress air
Convert chemical energy to mechanical energy
Cool exhaust gases
Store fuel
Which type of combustion engine uses both air and fuel compressed together before ignition?
Spark-ignition engine
Diesel engine
Steam engine
Jet engine
In internal combustion engines, combustion occurs:
Outside the cylinder
In the boiler
Inside the cylinder
In the condenser
A two-stroke engine completes a power cycle in:
4 revolutions
1 revolution
2 revolutions
3 revolutions
In a four-stroke diesel engine, during the power stroke, the piston moves:
Downward
Upward
Stationary
Horizontal
The component in a boiler where combustion occurs is the:
Economizer
Furnace
Superheater
Steam drum
A device that provides air to the combustion chamber is called:
Injector
Forced draft fan
Governor
Air preheater
A pulverizer is used in combustion systems to:
Cool the flame
Mix air with steam
Grind solid fuel
Separate exhaust gases
Which of the following improves fuel combustion by heating incoming air?
Air preheater
Induced draft fan
Superheater
Condenser
The main purpose of a burner in a combustion system is to:
Supply water
Burn fuel efficiently
Reduce exhaust gases
Pump steam
Which of the following is a mechanical firing method?
Hand-firing
Pulverized coal firing
Automatic stoker firing
Oil atomizing
In pulverized coal firing, the fuel is:
Burned in lump form
Mixed with steam
Ground into fine powder
Compressed into briquettes
Underfeed stoker firing system feeds coal:
From the top
From below the grate
Directly to furnace walls
Through injectors
A chain grate stoker is used for:
Liquid fuels
Hand feeding
Even coal burning
Natural gas
Which of the following firing methods is commonly used in small boilers?
Mechanical stoker
Hand-firing
Pulverized coal system
Fluidized bed
The stoichiometric air-fuel ratio is the:
Ratio of water to fuel
Exact amount of air for complete combustion
Ratio of flue gas to fuel
Minimum air to ignite fuel
Too much excess air in combustion leads to:
High CO levels
Complete combustion
Heat loss
Fuel savings
Incomplete combustion results in:
CO₂ and water
High efficiency
Carbon monoxide and soot
Higher pressure
Combustion efficiency is improved by:
Reducing air supply
Using wet fuel
Ensuring proper mixing of air and fuel
Lowering combustion temperature
The flame color indicating efficient combustion is:
Yellow
Blue
Red
Black
What happens if combustion air is insufficient?
Fire goes out
Incomplete combustion occurs
Excess oxygen is produced
Flame temperature increases
Flashback in gas burners is caused by:
Low gas velocity
High gas pressure
Excess air
Wet fuel
A flame detector in combustion equipment is used to:
Adjust the fuel flow
Monitor exhaust temperature
Detect flame failure
Mix air and fuel
The best indicator of incomplete combustion in flue gas is the presence of:
CO
CO₂
N₂
H₂O
Which of the following is not a fossil fuel used in combustion?
Diesel
Natural gas
Coal
Hydrogen
In large combustion systems, fuel is atomized to:
Reduce fuel use
Prevent soot formation
Ensure complete combustion
Increase fuel pressure
Fuel oil viscosity affects:
Boiler water level
Draft pressure
Atomization and combustion
Steam pressure
A fluidized bed boiler enhances combustion by:
Cooling the fuel
Suspending fuel particles in air
Preventing mixing of air and fuel
Increasing flame size
A furnace explosion can occur due to:
Proper air-fuel ratio
Delayed ignition
Use of natural gas
Clean burners
What is the function of an ignition transformer in oil-fired burners?
Boost oil pressure
Preheat the air
Generate spark for ignition
Increase fan speed
