30 câu hỏi
Which of the following statements is not correct with respect to alcohols as alternate fuel?
Anti-knock characteristics of alcohol are poor
Alcohol contains about half the heat energy of gasoline/liter
Alcohol does not vaporize as easily as gasoline
Alcohols are corrosive in nature
Why a small amount of gasoline is added to alcohol?
To reduce the emission
To increase the power output
To increase the power efficiency
To improve cold-weather starting
What is a dual fuel engine?
The engine which uses gaseous and liquid fuel
The engine which uses two liquid fuels
The engine which uses two gaseous fuels
The engine which uses one liquid and any other fuel
Which of the following has the same combustion as HCCI (Homogeneous Charge Compression Ignition) engine?
SI engine
CI engine
Hybrid of both SI and CI engine
Wankel engine
Which of the following is true for the HCCI engine?
Emits high NOx and soot
Have a large power range
Efficiency is comparatively less
Pre-catalyst hydrocarbon emissions are higher
For which of the following engine lean-burn concept is ideal?
CI engine
SI engine
Free piston engine
Wankel engine
By which technique can the charge stratification be achieved?
Injection
Carburetion
Lean burn technology
Injection as well as carburation
Which of the following is true for stratified charge engine?
More prone for knock
Multi-fuel capabilities
More throttling losses
Overall rich mixture
What is true about the Wankel engine?
It is a rotary external combustion engine
It is more expensive
It has a longer operating cycle
It has less time to complete the combustion
Where is the variable compression ratio used?
SI engine
CI engine
Wankel engine
HCCI engine
Which of the following is true for stratified charge engine?
More prone for knock
It uses an overall rich mixture
It has a lot of throttling losses
It has multi-fuel capabilities
Which of the following is true about the Stirling engine?
High efficiency
Quiet operation
Compatible with alternative and renewable energy
High efficiency, quiet operation and compatible with renewable energy
Which of the following is one of the major exhaust emissions from CI engines compared to SI engines?
Oxides of nitrogen
Particulates
CO and CO2
Unburnt hydrocarbon
Which of the following causes the photochemical smog?
Excess O2
CO and CO2
Soot and particulate matter
NOx and HC
What does the blue smoke in diesel engine indicate?
Unburnt oil
HC
Nox
CO
During which condition of the vehicle does NOx emission in SI engine will be lowest?
Cruising
Idling
Accelerating
Decelerating
For what purpose is the Rhodium used?
To reduce CO and HC
To reduce Nox
To reduce CO
To reduce HC
Why is the fumigation technique used?
To control HC
To control Nox
To control CO
To control smoke
Why are lead compounds added in petrol?
Reduce knocking
Reduce HC emission
Reduce exhaust temperature
Increase power output
Which of the following cannot be reduced by thermal converters?
CO
HC
Soot
NOx
What can be reduced by using exhaust gas recirculation (EGR) effectively?
CO
Nox
HC
CO and HC
Three-way catalytic converters reduce the emission of CO, HC, and soot.
True
False
On which of the following does brake mean effective pressure (BMEP) in an engine depend upon?
Speed and torque
Speed and power
Torque
Speed
What is gasohol?
90% ethanol + 10% gasoline
10% ethanol + 90% gasoline
40% ethanol + 60% gasoline
50% ethanol + 50% gasoline
Which of the following is a disadvantage of hydrogen as a fuel in IC engine?
Storage is easy
Low NOx emissions
Detonating tendency
Easy handling
Which of the following is the advantage of hydrogen as a fuel?
High volumetric efficiency
Low fuel cost
No HC and CO emissions
Relatively safe
What is the major disadvantage of LPG as a fuel in the automobile?
Reduction in the life of the engine
Less power compared to gasoline
Reduction in the life of the engine and less power compared to gasoline
Knocking tendency
Why alcohols cannot be used in CI engines?
Alcohols have a high self-ignition temperature
The latent heat of vaporization is low
Alcohols have high self-ignition temperature and low latent heat of vaporization
High efficiency
Which of the following is the major constituent of natural gas?
Methane
Ethane
Butane
Propane
What is octane number of natural gas?
60-80
80-100
>100
<60
60