Automobile Engineering (22656)
1.
Explain The Reason That Why Big Tyres Are Used In Rear Of Vehicles
Answer
:
Large
tyres provide larger surface area touching the ground, thus providing the more
pulling power. Basically tractors have larger rear tyres because tractors don’t
have to operate at higher speeds, thus getting the same ground speed with
larger tyres. Moreover gear ratios don’t have to be as high as b/c of the
tyres.
2.
What Is Kingpin Offset? State Some Of Its Application.
Answer
:
The
kingpin offset is the part, basically called as pivot used in the steering of
the vehicles. This offset helps in rotating of the steering and thus it’s very
useful in steering mechanism of the cars.
Applications:
This is also used to measure scrub radius with the help of geometric parameters
of wheel plane above and below ground level. It provides directional stability
to the vehicles when it i combined with the caster.
3.
Explain The Basic Difference Between Bs2 And Bs3 Engine.
Answer
:
The
basic difference of BS2 and BS3 engines is the presence of catalytic convertor.
Catalytic convertor is present in BS3 engine which helps in reducing the
formation of HC and CO. While in BS2 engine, no catalytic convertor is present
which forms HC and CO. Thus in BS3 engine there is no emission of harmful CO
and HC. The full form of BS is bharat stage, which is a standard of emission in
India.
4.
What Is An Injector Pressure In Heavy Vehicles? Why It Is Used?
Answer
:
Injector
pressure i s the pressure at which the fuel can be injected into the vehicle.
In heavy vehicles, injector pressure is 220 kg/cm square. It is used to set up
the standard fuel injection in the vehicles. With the help of injector pressure
we can calculate the amount of fuel needed, through the following formula:
Est.
Horsepower x B.S.F.C / No. of injectors x duty cycle = lb/hr per injector
cc
= lb/hr x 10.5
5.
During The Drive Torque, What Will Be The Weight Shift?
Answer
:
In
case of cars the torque is applied to the rear wheels, thus limiting
accelerator due to front wheel drive due to weight transfer. This drive is
bolted to the chassis of the car. Modern manufacturers therefore design rear
wheel drive to have similar handling to front wheel drive wherever possible via
suspension tuning.
6.
In A Tractor, How The Hydrostatic Propulsion Systems Work?
Answer
:
This
system is based on Pascal’s law. In a tractor the pressure is same, so the
force given by the liquid to the surrounding is equal to the pressure X area.
Thus, obeying the Pascal’s law hydrostatic propulsion system is designed,
similarly small piston feels small force and the large piston feels larger
area.
7.
Explain The Reason That Why The Tyres Are Always Black In Colour. Is This
Phenomena Related To The Heat Conduction?
Answer
:
Tyres
colour is black due to the proportion of carbon mixed in it during the
vulcanization of the rubber, to make the tyre shear resistant. Without
vulcanization tyres won't be able to bear the friction heat and stress of the
road. Thus carbon is responsible for giving tyres the prominent black colour.
Adding of carbon prevents tyres from rapidly deteriorating because when ozone
combines with the ultraviolet light from the sun. It attacks the polymer of the
tyre.
8.
What Is Bhp? How Can You Measure Bhp?
Answer
:
BHP
is ‘Brake Horsepower’. It reflects the powerfulness of the brakes of the
vehicles. BHP stands for how much power will be required to make the engine
stop working i.e. to stop the rotation of the engine.
BHP
= 2 times pi times torque times revolutions; all this divided by 550. Pi is
3.1416 and torque is in pounds-feet, and revolutions are revs per second.
9.
What Will Happen If Someone Adds Oil To The Fuel Of Four Stroke Bike Engine?
Answer
:
This
will result in damaging of the engine faster. Adding oil will lead to the
higher wear and tear of the cylinder liner, piston and damage to the piston. It
will lead to abnormal combustion and knocking and detonation. Dark smoke and
abnormal sounds will be generated by the engine. One should not mix oil with
the fuel of four stroke engine.
10.
How Will You Differentiate Between Two Stroke Engine And Four Stroke Engine?
Answer
:
In
case of two stroke engine, rotation of crank shaft will be power stroke for
every two rotations. During compression stroke, fuel will flow towards the
crank case(suction) and during power stroke, exhaust will emit the burnt fuel
through the transfer ports.
While
in case of four stroke engine, rotation of crank shaft will be power stroke for
every four rotation. Moreover, suction compression power and exhaust strokes
are separate as there will be inlet and exhaust valves.
11.
What Is The Size Of The Recommended Compressor Cfm? Where It Can Be Used?
Answer
:
It
is generally used in spray painting of very small areas. It can be used where
painting with brush is very difficult. thus to improve the rate of painting the
spray painting is used as this method is very fast and efficient. Usually
reciprocating compressors are used but size depends on requirements.
12.
What Is The Range Of Engine Efficiency In Case Of Two Stroke Engine?
Answer
:
The
two stroke engines have very high range to be compared to the four stroke
engines. Because power stroke is generated every two revolution while in four
stroke, power stroke is generated every four revolutions.
13.
What Do You Understand By Cc Of Engine?
Answer
:
The
meaning of CC is cubic centimeters. It represents the total volume of the
engine cylinder. This reflects that the engines with more CC can generate more
powers than the other engines. CC can also be related as inversely proportional
to the fuel consumption.
14.
What Is Back Compressor In Engines?
Answer
:
Back
compression means the compression capability of the engine. An diesel engine
can compress at the ratio of 14:1 to as high as 25:1. Thus the higher
compression leads to better efficiency of the engine. Thick black smoke is
emitted when the engine’s compression is reduced which leads to the deformed
ead-gasket lead into crankcase.
15.
How Air Conditioners Work In Cars?
Answer
:
Air
conditioners are based on the principles of evaporation and condensation and
then compression and expansion. The hot air of the car is removed by the
process of evaporation and then the condensation of the evaporated air takes
places which is then further compressed by the compressor and then finally
expanded to us in the form of cold breeze. Somehow, Air conditioning reduces
the average of the car, as the energy is required to remove the hot air and
then compression and expansion.
16.
What Are Three Methods Of Heat Transfer?
Answer
:
Three
methods of heat transfer are conduction, convection and radiation.
- Conduction: The transfer of energy by collisions between the
atoms and molecules in a material.
- Convection: Transfers heat when particles move between objects or
areas that differ in temperature.
- Radiation: The transfer of energy by waves.
17.
Why The Plastic Materials Used In The Screwdriver's Handles?
Answer
:
Due
to non-conducting nature of plastic, it is widely used for the electricity
purposes. Moreover, plastic is cheap and strong so it is less prone to damage.
Furthermore, plastic does not bend and does not slips from the users hands.
18.
Does Diesel Engine Powered Automobile Use Unit Pump And Unit Injector?
Answer
:
In
the case of the engines powered by diesel fuel supply systems, unit pump &
unit injector are operated by camshaft & thus pressure of injected fuel
depends on engine speed. Whereas,in common rail systems it is independent of
engine speed.
19.
If We Use Gasoline In Diesel Engine, What Will Happen?
Answer
:
Adding
gasoline to the diesel engine may blast off the engine. Compression ratio of
the petrol engine is 6 to 10 and diesel engine is 15 to 22. Thus gasoline will
get very highly compressed and might result in blast off engine.
- Question
20. What Is Octane Number And Cetane Number?
Answer
:
Octane
number can be defined as the percentage, by volume, of iso-octane in the
mixture of iso-octane and h-heptane. It is the measure of rating of SI engine.
While
cetane number can be defined as the percentage,by volume, of n-cetane in the
mixture of n-cetane and alpha methyl naphthalene. It is the measure of rating
of CI engine.
21.
Explain The Significance Of Governor In Automobiles?
Answer
:
Governor
is an important component of automobile engine. It is used to regulate the main
speed of engine during the variations in loads. With the variations in the
load, fuel supply has to be maintained. This task is performed by the governor.
In the case of high load on the engine, speed decreases, hence fuel supply has
to be increased and similarly when load decreases then the fuel supply has to
be decreased.
22.
What Is The Reason For Emitting The White Exhaust Smoke During Start Of The
Vehicle? How Will You Prevent This?
Answer
:
The
main cause of white smoke is water or anti-freeze entering the cylinder, so the
engine starts to burn it with the fuel. That white smoke is nothing but
steam.
Prevention
measures: There are special gaskets i.e. head gaskets and primary gaskets that
prevent the anti-freeze from entering into the cylinder area. This anti-freeze
will produce a white steam which will accumulate at the tailpipe area.
23.
What Are Mpfi And Tpfc Systems?
Answer
:
MPFI
stands for Multi Point Fuel Injection. In this system fuel is injected into the
intake ports which is situated just upstream of each cylinder’s intake valve.
These systems are sequential systems, in which injection is timed to coincide
with intake stroke of each cylinder.
TPFC
stands for transient power fuel control system. In this type of systems
constant choke carburetor is used. The salient feature of this carburetor is
that it provides jerk less engine raise. In these systems, throttle valve
creates vacuum which opens the slide which controls the air fuel ratio through
a tapered jet.
24.
What Is Sae? Mention The Importance Of Sae To The Automobile Domain.
Answer
:
SAE
stands for society of automotive engineers. This society is responsible for
developing the standards for the engineering of powered vehicles of all kind.
The vehicles may include car, boat, truck and even aircraft. SAE has developed
standards for ground vehicles and aerospace vehicles. SAE also encourages
students of engineering, technology, science and math’s disciplines. This
society has been publishing technical information since 1906.
25.
What Is Dtsi? Why This Technology Is Used In Motor Bikes?
Answer
:
DTSI
stands for Digital Twin Spark Ignition. This is used to get better combustion
in the combustion chamber. In this technique double spark plugs are used to
obtain better combustion of fuel in cylinder head. Through this technique fuel
is ignited properly. Moreover it provides better efficiency and it is
economical in fuel consumption.
26.
How Does The Thermostat Work?
Answer
:
When
the engine is too cold the thermostat closes the main valve, thus stopping the
flow to the radiator. When the engine is too hot, it opens the main valve for
normal circulation through the radiator.
27.
What Is A Pressure Cap In The Radiator?
Answer
:
It
is a seal in the radiator that maintains the selected pressure in the cooling
system when the engine is hot.
28.
Why Does A Compression Engine Use High –octane Fuel?
Answer
:
The
property of a fuel, which describes how fuel will or will not self-ignite, is
called the octane number or just octane. Engines with low compression ratios
can use fuels with lower octane number, but high compression engines must use
high-octane fuels to avoid self-ignition and knock.
29.
What Is The Use Of Hydrogen In Automobile?
Answer
:
Low
emissions. Essentially no CO or HC in the exhaust as there is no carbon in the
fuel. Most exhaust would be H2O and N2 Fuel availability. There are a number of
different ways of making hydrogen, including electrolysis of water.
30.
What Is The Use Of Natural Gas In Automobiles?
Answer
:
High
octane number makes it very good S.I engine fuel
Low engine emissions. Less aldehydes than with methanol
31.
What Is Pitching In The Suspension System?
Answer
:
Pitching
is a rocking action about a transverse axis through the vehicle, parallel to
the ground. The front suspension moves out of phase with the rear, experiencing
the rocking effect due to pitching.
32.
What Do You Mean By Independent Suspension?
Answer
:
Independent
suspension refers to the mounting of the wheel on a separate axle, so that road
shocks affect only the particular wheel.
33.
What Is Pan Hard Rod Or Track Bar?
Answer
:
A
pan hard rod is a bar or tube running from one side of the axle to the frame on
the other side of the vehicle. It helps the leaf spring in keeping the axle
centered under the body during turning a corner.
34.
What Is Clutch Drag?
Answer
:
When
the clutch is not disengaging fully and provides some difficulty in changing
the gears then this defect is called clutch drag.