Question No. 51
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.
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.
Question No. 52
Explain the basic difference between BS2
and BS3 engine.
Answer: The
basic difference of BS2 and BS3 engines is the presence of catalytic converter.
Catalytic converter is present in BS3 engine which helps in reducing the
formation of HC and CO. While in BS2 engine, no catalytic converter 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.
Question No. 53
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 × 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.
Question No. 54
Explain the reason that why the tyres are
always black in color. Is this phenomena related to the heat conduction?
Answer: Tyres color 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 color.
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.
Question No. 55
What is back compressor in engines?
Answer: Back
compression means the compression capability of the engine. A 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 head-gasket lead
into crankcase.
Question No. 56
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 slip from the users hands.
Question No. 57
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.
Question No. 58
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 carburettor is used. The salient feature of this carburettor 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.
TPFC stands for transient power fuel control system. In this type of systems constant choke carburettor is used. The salient feature of this carburettor 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.
Question No. 59
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.
Question No. 60
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.
What do you
mean by Independent suspension?
Independent
suspension refers to the mounting of the wheel on a separate axle, so that road
shocks affect only the particular wheel.
Question No. 61
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.
Question No. 62
What is the cause of black smoke from the
exhaust?
Answer: There
are various possible causes of black exhaust smoke, almost all of
which should let you know that your engine is burning too much fuel. Check all
of your vehicle's intake
components, including your air filter, sensors, fuel injectors, and
fuel-pressure regulator. One other cause
could be a clogged fuel line.
Question No. 63
What type
gear is used for sun gear?
Answer: Most
commonly used gears as Sun gears are Spur gears and Helical
gears. In some cases Epicyclic Gear trains with Bevel Gears are also
used.
Question No. 64
Why don't
auto-rickshaws have differential gears?
Answer:
Auto-Rikshaws have engine directly connected to rare end wheels. There is no
need of differential gears.
But some Auto-Rikshaws
are not driven by the engine directly instead they use a differential gear. The
entire differential mechanism is inside the gearbox unlike other vehicles.
Question No. 65
Which
type of gears is used in motorcycle gearbox?
Answer: Spur
gears in sequential arrangement are used inside a gear box of a motorcycle.
While chain and sprocket are engaged to transmit power from engine to the rear
wheel.
Question No. 66
How many
differential gears are used in a car?
Answer: There
is only one differential working in a car, however in a differential 5
bevel gears are used, one is mounted upon the shaft, the 2 are
mounted upon the 2 shafts connecting to the rear wheels, the other 2 gears are
so arranged so that they mess with the gears upon the wheel shafts.
Question No. 67
Which
Mechanism is used in Automobile gearing system?
Answer: Differential
mechanism
Question No. 68
1 hp is how
much watt?
Answer: 746.2Watt
Question No. 69
Explain
Bicycle rear wheel Sprocket working?
Answer: Rear
wheel sprocket works under the principle of ratchet and pawl.
Question No. 70
The
Fatigue life of a part can be improved by?
Answer: Improving
the surface finish by Polishing & providing residual stress by Shot
peening.
Question No. 71
When
crude oil heated Which Hydro carbon comes first?
Answer: Natural
gas (Gasoline) at 20 degree Celsius
Question No. 72
What type
of metal is used in a propeller?
Answer: Aluminium,
stainless steel, magnesium bronze, NIBRAL (nickel, brass, aluminium)
Question No. 73
What is
more dangerous longitudinal stress or Hoop stress and why?
Answer: Hoop
stress is more dangerous than longitudinal stress, because the dangerous area
coming under the hoop stress is circumferential, while in longitudinal, the
axial area will come under dangerous area will be less than circumferential
area. So the hoop stress is more dangerous than longitudinal stress.
Question
No. 74
For the
purpose of inflating car tyres, spray painting, etc. i.e. say a small workshop,
what size of a compressor (CFM) is recommended? It will be generally for a
hobby use and not commercial use?
Answer: Spray painting it is generally used for
painting in a very smaller area of any part and where it is very hard to
paint in a brush and to improve faster rate of painting, spray painting
r used. Usually reciprocating compressor r used but size depends upon
requirement.
Question
No. 75
What is
king pin offset?
Answer: A geometric parameter which is positive if
the kingpin axis intersects the wheel plane at or below ground level, or is negative
if the point of intersection is above ground level. Also called scrub radius.