AUTOMOBILE ENGINEERING 2 MARKS QUESTIONS AND ANSWERS
EGS.PILLAY ENGINEERING COLLEGE,NAGAPATTINAM
DEPARTMENT OF MECHANICAL ENGINEERING
REGULATION 2013
ME 6602 AUTOMOBILE ENGINEERING2 MARKS QUESTIONS AND ANSWERS
UNIT
-1
VEHICLE
STRUCTURE AND ENGINES
1. How the internal combustions engines are classified? Automobiles can be
classified with respect to different purposes as follows
(i)With respect to purpose.
(ii) With respect to fuel used.
(iii) With respect to capacity.
(iv) With respect to number of wheels.
(v) With respect to the drive of vehicle.
(vi) With respect to the side of drive.
(vii) With respect to transmission.
(viii) With respect to their construction.
2. Classify the vehicles based on their load carrying capacity.
(i)Heavy
transport vehicle. Ex. Bus, lorries, Trucks.
(ii)Light
transport vehicle. Ex. Car, Scooter, Jeeps.
3. What are the loads acting on a chassis frame?
Inertia load, Static load, Impact load,
over load.
4. List out the forces acting on the chassis frame. (i)Weight of the components and
passengers causing a sagging effect due to bending action.
(ii)Horizontal
forces provided by road irregularities.
(iii)Upward
twisting force caused by road shocks.
5. Give any two advantages of frameless construction over the
conventional framed construction.
(i) The stresses are evenly
distributed’
(ii) A strong structure with
good tensional rigidity.
6. How
are automobiles streamlined based on transmission?
(i)Conventional.
Ex Most of Indian vehicles.
(ii)Semi-automatic .Ex. Most of British
vehicles.
(iii)
Automatic, Ex. American vehicles.
7. What are the shapes of frame section?
Channel, Tubular, and Box type are the types
of frame sections.
8.
Write down the firing order of 4 and 6 cylinder engine.
For 4 cylinder engine, the firing order is 1 - 3 – 4 -2 or 1 – 4 – 3 – 2.
For six cylinder engine ,the firing order is 1 –
5 – 3 – 6 – 2 – 4 or
1 – 4 – 2 – 6 – 3 – 5.
9. Briefly explain ”off road” vehicle with example.
Vehicles which are capable of driving on and
off paved or gravel surface are
called off- road vehicles. Usually, these vehicles have large tires
with deep, open treads, a flexible
suspension or even caterpillar trucks.
Example ,tractors, forklifts,
cranes, backhoes, bulldozers and golf
carts.
10. Give the requirements of air fuels ration
in SI engine.
The SI engine automobiles run with
the help of a mixture of gasoline and
air. The amount of mixture depends on
(i) engine displacement (ii) Maximum revolution per minute and (iii) volumetric efficiency.
11.What
are the control mechanisms of CO emissions?
(i)By using reactor in the
exhaust manifold.
(ii)By using after burner.
(iii)By using catalyst convertor.
12.What
are the objectives of super charging?
It will improves the
efficiency of engine. less fuel consumption.
13. What are the components of water
cooling method?
Water pump, radiator tube, upper tank, lower
tank, thermostat valve etc.
14.What is the function of a bumper?
A bumper is the front-most or rear-most part,
which is designed to allow the vehicle to sustain an impact without damage to
the vehicle's safety systems
15. What is clearance volume?
And what are its
effects? The volume above the piston, when it reaches TDC is known as clearance
volume. The clearance volume is inversely proportional to the compression
ratio.
UNIT 2
ENGINE AUXILIARY SYSTEMS
- What
do you understand by turbo charging? State how it differs from super charging.
Super charging is the process of supplying to
the engine the air fuel mixture above the atmospheric pressure .A super charger
increases the pressure of the air fuel from the carburetor before it enters the
engine
Turbochargers are used for better turbulence of air fuel mixture,
increase volumetric efficiency and to maintain the power of IC engine at high
altitudes.
- List
down the sensors used in electronic engine management system.
(i)Throttle position
sensor.(ii)Exhaust gas oxygen sensor(Ego).(iii)Manifold absolute pressure
sensor(MAP).(iv)Temperature sensor.(v)Speed/Timing sensor.(vi)Engine position sensor.(vii)EGR
diagnostic switch.(viii) EGR diagnostic
control switch.(ix)EGR Valve position sensor.(x)Coolant temperature sensor.(xi)Intake air temperature
sensor,(xii)Mass air flow sensor(MAF).(xiii) Crankshaft position
sensor.(xiv)Vehicle aped sensor.(xv)Knock sensor,(xvi)Brake ON or OFF sensor.(xvii)Heated
wind shield sensor.(xviii)High gear switch.
- What
do you understand by the terms MPFI and CRDI? State it advantages from the
conventional system. (i)Common
Rail Diesel injection:
In this system a multi cylinder high pressure
pump is used to supply the fuel at a high pressure to a common rail or header.
A metered quantity of fuel is supplied to each cylinder from the rail.
(ii)Multi
Point Fuel Injection:
In
this system, each cylinder of the engine is provided with an individual injection valve, a high-pressure pump and a metering
device. At all operating loads and speeds each pump in this unit will precisely
supply the fuel to each cylinder.
- What
is engine management system?
An electronic engine
management system is made up of sensors,
actuators, and related wiring that is tied into a central processor called
microprocessor or microcomputer (a smaller version of a computer).
- Define
firing order.
The firing order is
defined as the combustion which take place in a multi cylinder engine based
on the cylinder position number.
- List
the types of injection system.
(i)Mono point injection
system, (ii) Multipoint injection system.
- What
is catalytic converter?
The catalytic converter
has a stainless steel box mounted on the exhaust system. It is placed between
exhaust manifold and silencer. It contains a catalyst of ceramic or metallic
base with an active coating incorporating alumina, ceria and other oxides and
combinations of the precious metals platinum, palladium and rhodium. The
catalytic convertor converts the pollutants like HC, CO and NO2 into
harmless gases.
- Name
the sources of automobile pollutant
1.Exhaust emissions
through tail pipe.
2.Evaporation Losses
through carburetor, and
3.Crankcase blow.
9. State the
important units of electronic fuel injection system.
(i)
Fuel delivery system
(ii)
Air induction system
(iii)
Sensors and air flow control
system
(iv)
Electronic control unit
10.
What is
exhaust gas recirculation?
Excessive nitrogen oxides (NO2) form,
when peak combustion temperature exceeds 1950oC. To lower the combustion temperature, many
engine have EGR system. It re
circulates about 10% of the inert gas
back into the intake manifold. The
cooler exhaust gas absorbs heat from the much hotter combustion process. This reduces peak combustion temperature and
lowers the formation of NO2.
11. State the purpose of turbocharger.
(i) To reduce weight per
horse power of the engine as required in aero engines.
(ii) To reduce the space
occupied by the engine as required in marine engines.
(iii) To have better
turbulence and this ensures more complete combustion giving a better greater power and low specific fuel
consumption.
(iv) To improve volumetric
efficiency of the engine at high altitudes, as in aero engines, and at high
speeds as in racing cars.
(v) To maintain the power of
a reciprocating IC engines even at high altitudes where less oxygen is
available for combustion.
12.
.What is the function of
a catalytic converter in SI engine?
The catalytic converter
converts the pollutants like HC, CO and NO2 into harmless gases. It oxidizes HC
and CO into water and CO2.
13. What is Gasoline Direct Injection?
The gasoline (petrol) is directly into the
cylinder at the end of compression stroke as such in diesel engines. This is called
Gasoline Direct Injection (GDI)
14. What is conventional
ignition system?
The conventional
ignition system gets its electrical voltage either from battery or dynamo,
which will be boosted to a very high voltage due to which spark is produced in
the cylinder to combust the mixture.
15. Define common rail injection system.
A common rail which is
maintaining high fuel pressure is connected to individual fuel injectors of a
multi cylinder engine.
UNIT 3
TRANSMISSION
SYSTEMS
1. Mention the function of an over drive. State its advantages.
Overdrive is a device
which is used to step up the gear ratio is the car. It is mounted in between transmission and
propeller shaft.
(i)
It
allows a lower engine speed to maintain the car at highway speed.
(ii)
It
does not require as much power to keep it moving. Therefore, the engine can turn more slowly,
produces less power, and still maintain car speed.
(iii)
This
system saves fuel.
(iv)
Wear
on the engine and accessories are reduced.
2. What do you understand by Hotchkiss drive?
In Hotchkiss drive the
deflection of spring helps to improve the flexibility and damp shocks. Then the driving force is transferred from
the axle casing to the front end of the spring and then to the frame. Hence, both rear-end torque and driving
thrust are opposed by springs. In Hotchkiss drive, the driving thrust is
transferred to the rear end of the frame through cup and gearbox shaft.
3. What is the function of a slip joint?
A slip joint is used
between the propeller shaft and the universal joint connecting the propeller
shaft to compensate for this change of length and it helps to transmit power
from the engine to the rear axle at the same time.
4. What is the function of differential in a vehicle?
(i)Straight ahead travel.
(ii)Turning.
(iii)One wheel on a Muddy surface.
5. What is the function of a Clutch?
(i)
To
permit engagement of disengagement of a gear when the vehicle is stationary and
the engine is running.
(ii)
To
transmit the engine power to the lead wheels smoothly without shocks to the
transmission system while the vehicle is in motion.
(iii)
To
permit the engaging of gears when the vehicle is in motion without damaging the
gear wheels.
6. Mention any two uses of Propeller Shaft.
(i)
It
transmits rotary motion of the gearbox output shaft to the differential and
then through the axle shafts to the wheels
(ii)
It
transmits motion at an angle which is varying frequently.
(iii)
It
allows some changes in length between gearbox and rear axle.
7. Where planetary transmission is used in automobiles?
Planetary transmission
is used for overdrive in automobiles.
8. Why is multi-plate clutch of smaller diameter preferred over
single plate clutch in high performance car?
(i)
Increased
torque transmission capacity.
(ii)
The
diameter is reduced as it has more friction surface which reduces the size of
the clutch assembly.
(iii)
Highly
reliable.
(iv)
Suitable for heavy vehicles.
9. Why is tubular section propeller shaft more preferred?
The tube is used bearing
to support the propeller shaft. Only one
universal joint is enough at the gearbox.
There is no sliding joint needed in the propeller shaft. The rear and torque and driving thrust are
carried up by the torque tube.
10. Mention different types of rear axle with its applications.
There are three types of live axles:
1.Semi-floating.
2.Three-quarter
floating, and
3.Full-floating.
11. Why universal joint and slip joint are provided in power
transmission )system?
A slip joint is used
between the propeller shaft and the universal joint connecting the propeller
shaft to compensate for this change of length and it helps to transmit power
from the engine to the rear axle at the same time.
Universal joints are
used for connecting two shafts inclined to one another at angles and also for
transmitting the rotary motion from the engine to the road wheels throughout
the variation in position of the rear axle with respect to the gear-box and
chassis.
12. How is the length of propeller shaft varied automatically ?
The variation in the
length of the propeller shaft is due to the propeller shaft and rotation of the
rear axle housing. The rear axle
rotation housing is in the form of arcs with different points as their centers
of rotation. But rear axle housing moves
in a shorter arc when compared to the propeller shaft. This is due to the centre of the rear axle
housing arc which is the point of attachment of the rear spring or control arm
ot the vehicle frame. It causes a
reduction in the length occupied by the propeller shaft making the angle
between the transmission and the propeller shaft increased.
13. Name the possible causes for the propeller shaft to develop
noise while running.
Since the propeller shaft front end is meshed
with the gear in gearbox and in the center there is a universal joint and in
the end it meshes with the differential gears
these rotation of gears makes noise
14. Define the term double declutching.
In gear box while
disengaging the gears sometimes much more has to be applied, therefore a
technique double de clutching is applied for shifting the gears.
15. Why epicyclic gears are used in overdrive units?
In the transmissions,
the high gear position produces a 1:1 ratio between the clutch gear and
transmission output shaft. There is
neither gear reduction nor gear increase through the transmission. It is the direct drive. At intermediate and higher car speeds, it is
sometimes desirable to have the transmission output shaft turned faster than
the clutch gear and engine crankshaft.
Therefore, some transmission systems are designed with gears to provide an
over drive ration.
UNIT
4
STEERING,
BRAKES AND SUSPENSION SYSTEMS
1. Define Toe in and Toe out.
The toe-in refers to as
the turning-in of the front wheels from the straight ahead position. If the
distance between the top wheels of the front axle is less than the distance of the bottom wheels is called as
Toe in.
If the distance between
the top wheels of the front axle is greater than the distance of the bottom wheels is called as
Toe out.
2. Define camber ,caster with sketches. Camber:
When the front of the vehicle is viewed, the
angle between the centre line of the tyre and the vertical line is called as
camber.
Caster:
Tilting of kingpin axis either forward or
backward from the vertical line is known as castor.
3. Define turning radius.
The radius of the circle
on which the outside front wheel travels when the front wheels are turned to
their extreme outer position is called as turning radius.
4. What are the Wheel alignment parameters?
The parameters are (i) Camber (ii) Caster (iii) Toe- in (iv)
Toe-out (v) Kingpin inclination.
5. List the use of Suspension systems.
(i)
To
eliminate the road shocks from
transmission to the vehicle components.
(ii)
To
maintain stability of the vehicle in pitching or rolling while in motion.
(iii)
To
safeguard the occupants from read shocks.
(iv)
To
keep proper steering geometry.
6. What is the purpose of a shock absorber?
(i)
To
control the vibrations on springs
(ii)
To
provide comfortable ride
(iii)
To
act flexible and to be rigid enough
(iv)
To
resist the unnecessary motion of the spring
7. What are the functions of brake lining?
Brake line is are either riveted or cemented to
the bearing surface. The brake lining helps to stop the vehicle or slow down
the vehicle when the brake shoes come in contact. A friction is developed
between brake shoes and lining.
8. What is steering ratio?
The number of degrees
through which the steering wheel is turned is divided into the number of
degrees that the front wheels turn. It is known as overall steering ratio.
9. State the importance of providing king pin inclination.
(i)Both king pin inclination and castor give
directional stability.
(ii)Particularly steering effort is reduced when
the vehicle is stationary.
(iii)Tyre wear also is greatly reduced.
(iv)During turning of the wheel, this
inclination raises the vehicle. By this, a force is exerted on the wheels to
straighten up automatically after completing its turn.
10. Why disc brakes are preferred in front wheels and drum
brakes in rear wheels?
The
disc brakes are very much effective in surface area and heat dissipating
properties than drum brakes. So disc brakes are used in front wheels.
11. Enlist the different types of steering gear box.
(i)
Worm
and roller.
(ii)
Cam
and roller.
(iii)
Cam
and turn lever.
(iv) Worm and sector.
(iv)
Cam
and peg.
(v)
Screw
and nut.
(vi)
Recirculating
ball.
(vii)
Worm
and ball bearing.
Rack
and pinion.
12. List out the different types of stub axle
(i)
Elliot.
(ii)
Reversed
elliot.
(iii)
Lamoine.
(iv)
Reversed
lamoine.
13.
Define ‘king pin
inclination’.
The angle between the
vertical line and centre of the king pin or steering axle when viewing is
carried out from the front of the vehicle is called as king pin inclination.
14. Distinguish between anti lock braking system and
conventional braking system.
ABS
prevents a vehicle’s brakes from locking up and skidding during hard stops on
wet or icy roads. In conventional brake it will completely lock the wheels.
ABS helps a driver to control the vehicle under
heavy braking by preventing the wheels from locking up but not in conventional
system the entire force has to be applied by the driver.
15. Write the functions of steering system in an automobile. (AU 2013)-2
(i)
It
provides wheels swinging to the left or right.
(ii)
It
provides vehicle turning as per the will of the driver.
(iii)
It
helps in achieving the self-rightening effect.
(iv)
It
provides directional stability.
UNIT 5
ALTERNATIVE ENERGY SOURCES
1.
What do you understand
by gasohol
Gasohol is a mixture of
one part ethanol (commonly known as grain alcohol or beverage alcohol) and nine
parts unleaded gasoline.
2. Mention the
limitations of using hydrogen as automobile fuel. (AU 2010)
(i)
Its
energy density, either as a gas or as a liquid is quite low.
(ii)
Since
it is a highly reactive fuel, special safety precautions are necessary in
handling it.
(iii)
It
can produce pre-ignition and back flash in engines, again due to its high
reactivity.
(iv)
Energy
content of air-hydrogen mixture is lower than that of hydro-carbon fuels.
(v)
NOx
emissions are higher for hydrogen peak values.
3. Indicate the various
constituents of CNG. (AU 2010)
General composition for Natural Gas
Methane(CH4) : 85-90%
Ethane(C2H6) : 5-7%
Propane(C3H8) : 2%
Carbon
di oxide : 3-5%
Others : 1%
4. List the different methods of storing hydrogen.
(i)
Stored
as compressed gas in cylinders.
(ii)
Stored
as liquid in cryogenic containers.
(iii)
Stored
in absorbed form as metal hydrides.
- What
are the fuel cells?
A fuel cell is a device
that harnesses the energy produced during the electro chemical reaction between
hydrogen and oxygen. The products are
water heat and electricity. There is no oxides of nitrogen, HC and Carbon
monoxide.
- What
is the use of hydrogen in the
automobile?
Hydrogen is an excellent
fuel ,which could be the acceptable as permanent energy source that meets most
of the obvious requirements for universal application of energy consumptions in
automobiles.
7.
What
are the advantages of compressed natural gas as a fuel in I.C.engines?
CNG
is lighter than air and therefore dispersed quickly in the event of leakage.
(ii) Natural gas ignites
at higher temperature than petrol and diesel.
(iii)Natural gas
provides clean burning characteristic.
(iv)
Natural
gas does not saturate flammable materials.
8.
.What are the advantages of fuel cell
vehicle?
(i)The fuel cell have
very low emission of pollutants.
(ii)The oxygen air bags
are very useful for the passengers.
(iii)The fuel cell
prevents the depletion of fossil fuel.
(iv)Provide all the
benefits of battery and more along with extended range.
9. How does the energy flow take in electric
vehicles?
The energy flow takes place from a lead acid
battery which is used for starting purpose in most of the automobiles.
10.Differentiate
parallel and series hybrid vehicle.
Series Hybrid: Here the engine runs a motor
directly and also charges a battery. Thus the motor drives the vehicle
always.Parallel Hybrid: Here the IC Engine and the electric motor are couple to
the wheels in parallel. The engine runs at its optimal point and the motor
supplements the torque to the engine.
11.Write the advantages of biofuels.
(i)Bio fuels is a very promising
alternate fuel diesel engines.
(ii)They are renewable and can easily produced
in rural areas.
(iii)Reduces emission of unburnt hydrocarbons ,CO and particulate matter.
(iv)Reduce the sulfate fraction.
12.What is gasohol?
Gasohol is a mixture of one part ethanol
(commonly known as grain alcohol or beverage alcohol) and nine parts unleaded
gasoline.
13.Name the components of an electric
vehicle.
(i)Motor (ii)Power Pack (iii)On Board Charger
(iv)Motor Controller (v)Energy Management System (vi)Regenerative Braking.
14.Define “transesterification process”.
Bio
diesel is produced from vegetable oils by converting the triglyceride oils to
methyl (or ethyl) esters with a process known as transesterification.
15.Enumerate
the limitations of electric vehicle.
1.Less initial torque.
2.more expensive.
3.Freqyent recharging of battery is
needed also battery charging needs more
time.
4.The performance is poor. 5.Less variety of vehicles
available in the market.
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