In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the
Beginning of suction stroke
End of suction stroke
Beginning of exhaust stroke
End of exhaust stroke
Correct Answer :
A. Beginning of suction stroke
Related Questions
In a petrol engine, if diesel is used, then the engine will
Not run
Run more efficiently
Run at high speed
Explode
A 75 cc engine has following parameter as 75 cc
Fuel tank capacity
Lube oil capacity
Swept volume
Cylinder volume
The increase of efficiency of a compression ignition engine, as the load decreases, is due to
Higher maximum temperature
Qualitative governing
Quantitative governing
Hit and miss governing
The working cycle in case of four stroke engine is completed in following number of revolutions of crankshaft
1/2
1
2
4
The knocking in spark ignition engines can be reduced by
Retarding the spark
Increasing the engine speed
Both (A) and (B)
None of these
A fuel of an octane number rating of 75 matches in knocking intensity as a mixture of
75% iso-octane and 25% normal heptane
75% normal heptane and 25% iso-octane
75% petrol and 25% diesel
75% diesel and 25% petrol
The colour of exhaust from diesel engine is generally
White
Bluish
Black
Violet
The thermal efficiency of diesel engines on weak mixtures is
Unaffected
Lower
Higher
Dependent on other factors
In loop scavenging, the top of the piston is
Flat
Contoured
Slanted
Depressed
The fuel air ratio in a petrol engine fitted with suction carburettor, operating with dirty air filter as compared to clean filter will be
Higher
Lower
Remain unaffected
None of the above
If V₁ is the jet velocity and V₀ is the vehicle velocity, then propulsive efficiency of a turbojet engine is
V₁/(V₀ + V₁)
V₀/(V₀ + V₁)
2V₀/(V₀ + V₁)
2V₁/(V₀ + V₁)
The combustion in compression ignition engines is
Homogeneous
Heterogeneous
Both (A) and (B)
None of these
A two stroke cycle engine gives ________ the number of power strokes as compared to the four stroke cycle engine, at the same engine speed.
Half
Same
Double
Four times
In a typical medium speed, 4-stroke cycle diesel engine
Fuel injection starts at 10° before to dead center and ends at 20° after tor dead center
Fuel injection starts at top dead center and ends at 20° after top dead center
Fuel injection starts at just before top dead center and ends just after top dead center
May start and end anywhere
In order to eliminate knocking in compression ignition engines, there should be
Short delay period
Late auto-ignition
Low compression ratio
High self ignition temperature of fuel
Gaseous fuel guarantees are based on
Calorific value of oil
Low heat value of oil
High heat value of oil
Mean heat value of oil
In a four stroke cycle, the minimum temperature inside the engine cylinder occurs at the
Beginning of suction stroke
End of suction stroke
Beginning of exhaust stroke
End of exhaust stroke
The size of inlet valve of an engine in comparison to exhaust valve is
More
Less
Same
More/less depending on capacity of engine
Polymerisation is a chemical process in which molecules of a compound become
Larger
Slowed down
Smaller
Liquid
A supercharged engine as compared to an ordinary engine
Is lighter
Requires smaller foundations
Consumes less lubricating oil
All of these
Fuel oil consumption guarantees for I .C. engine are usually based on
Low heat value of oil
High heat value of oil
Net calorific value of oil
Calorific value of fuel
The ignition of the charge by some hot surface within the engine before the passage of spark is called
Pre-ignition
Detonation
Ignition delay
Auto-ignition
A petrol engine has compression ratio from
6 to 10
10 to 15
15 to 25
25 to 40
For the same compression ratio
Otto cycle is more efficient than the Diesel
Diesel cycle is more efficient than Otto
Both Otto and Diesel cycles are, equally efficient
Compression ratio has nothing to do with efficiency
The inlet value of a four stroke cycle I.C engine remains open for nearly
180°
125°
235°
200°
In case of gas turbines, the gaseous fuel consumption guarantees are based on
High heat value
Low heat value
Net calorific value
Calorific value
A stoichiometric air-fuel ratio is
Chemically correct mixture
Lean mixture
Rich mixture for idling
Rich mixture for over loads
In compression ignition engines, swirl denotes a
Haphazard motion of the gases in the chamber
Rotary motion of the gases in the chamber
Radial motion of the gases in the chamber
None of the above
The fuel in diesel engine is normally injected at pressure of
5-10 kg/cm²
20-25 kg/cm²
60-80 kg/cm²
90-130 kg/cm²
The air standard efficiency of an Otto cycle compared to diesel cycle for the given compression ratio is
Same
Less
More
More or less depending on power rating