Automobile Engineering Interview Question and Answers Part 4

Automobile Engineering Basic Interview Question , quiz ,viva , oral Examination

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111. What are main advantages of power steering?

The manual effort required to turn the vehicle is getting reduced.
This layout also gives road feel to the driver.

112. What is function of suspension system in automobile?

The function of the suspension system is to isolate the vehicle and its occupants from road shocks and vibrations generated by the road surface, while maintaining steering control and stability at all times.

113. What is the function of brake? State its type.

The function of brake is to stop the vehicle within a short distance.
Types:
1. Mechanical brakes

Drum brakes
Disc brakes

2. Hydraulic brakes
3. Power brakes

Air brakes
Air-hydraulic brakes
Vacuum brakes
Electric brakes

114. What are the functions of front axles?

It carries the weight of the front of the vehicle
It carries the horizontal and vertical loads on bumpy roads
It works as a cushion through its spring for a comfortable side
In a four wheel drive, it also transmits power to the road wheels
When brakes are provided at the front wheels, it withstands bending stresses and torsional stresses

115. What I section at middle and oval section at end is preferred for front axle?

‘I’ section is suitable for bending loads and ‘circular’ or ‘oval’ section is suitable for torsional loads.
Hence I section at middle and circular or oval section at ends is provided in the front axle.

116. What are the different types of stub axles? Which is the most preferred one?

Elliot
Reversed Elliot
Lamoine
Reversed Lamoine

Out of these four types, Reversed Elliot is the most preferred type.

117. What is meant by the term “tread”?

The tread of a tire refers to the patterns on its rubber circumference that makes contact with the road.

118. What are differences between cross ply, radial ply and bias belted ply tyres?

difference between cross ply, radial ply, bias belted ply

119. What is a self energizing brake?

A brake is called self-energizing if it uses the rotational force of the wheel to help stop the automobile.

120. What is disc brake?

These brakes are different from drum brakes in that the drum is replaced by a circular plate and the brake shoes are replaced by a caliper which supports a pair of friction pads, one on each side of the disc. These pads are forced inward by the operating force and so retard the disc.

121. What is meant by electric brake?

In an electric brake, the current from the battery is utilized to energize an electromagnet within the brake drum. This actuates a cam to expand the brake shoes. When the current is not supplied, the cam and brake shoes are returned to the release position by retractor springs.

122. What is regenerative braking?

A regenerative brake is an energy recovery mechanism, which slows a vehicle by converting its kinetic energy into another form, which can be either used immediately or stored until needed. This contrasts with conventional braking systems, where the excess kinetic energy is converted to heat by friction in the brake linings and therefore wasted.

123. List the advantages of hydrogen fuel used in automobiles.

It can be manufactured from water through electrolysis process
It does not contain carbon. Hence, CO and unburned HCemissions are not present
The flame speed is highest. Hence it results in high thermal efficiency
It has wide ignition limits.

124. What is a hybrid vehicle?

A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle. The term most commonly refers to hybrid electric vehicles (HEVs), which combine an internal combustion engine and one or more electric motors.

125. What is a fuel cell?

A fuel cell is an electrochemical device that converts a source fuel into an electrical current and water. It generates electricity inside a cell through reactions between a fuel and an oxidant, triggered in the presence of an electrolyte.

126. Write the composition of LPG and CNG.

Composition of CNG
CH4 = 70.9%, C2H6 = 5.10%, H2 = 3%, CO + CO2 = 22%
Composition of LPG:
Propane= 30 % and Butane = 70 %

127. Define detonation and pre-ignition.

The abnormal combustion occurring in IC engines is called as detonation. This results in sudden rate of pressure rise, abnormal heat release, heavy vibrations of the engine and loud noise operation. The ignition of the air-fuel mixture before the introduction of the spark in the combustion chamber is called as pre-ignition.

128. What are the advantages of an electric car?

No emissions from an electric car
It does not depend upon the availability fossil fuels

129. State the advantages of fuel cell.

Higher efficiency than diesel or gas engines.
Quiet operation.
Fuel cells can eliminate pollution problems
Don’t need conventional fuels such as oil or gas and can therefore reduce economic dependence on oil producing countries, creating greater energy security for the user nation.
The maintenance of fuel cells is simple since there are few moving parts in the system.

130. What are the types of fuel cell?

Proton exchange membrane fuel cell
Alkaline fuel cell
Direct methanol fuel cell
Solid oxide fuel cell
Molten carbonate fuel cell

131. What are the alternative fuels?

Alcohols, Hydrogen, Natural Gas, CNG, LNG, LPG, Bio Gas, Producer Gas, Coke oven Gas, Water Gas, Gasohol, Biodiesel

132. What are the various properties of gaseous fuel?

Advantages

Gaseous fuels due to erase and flexibility of their applications possess the following advantages over solid or liquid fuels:

(a) They can be conveyed easily through pipelines to the actual place of need, thereby eliminating manual labour in transportation.
(b) They can be lighted at ease.
(c) They have high heat contents and hence help us in having higher temperatures.
(d) They can be pre-heated by the heat of hot waste gases, thereby affecting economy in heat.
(e) Their combustion can readily by controlled for change in demand like oxidizing or reducing atmosphere, length flame, temperature, etc.
(f) They are clean in use.
(g) They do not require any special burner.
(h) They burn without any shoot, or smoke and ashes.
(i) They are free from impurities found in solid and liquid fuels.

Disadvantages
(a) Very large storage tanks are needed.
(b) They are highly inflammable, so chances of fire hazards in their use is high

133. What is CNG?

Compressed Natural Gas. It is typically stored in a tank at a pressure of 3,000 to 3,600 pounds per square inch.

134. What is BIO- DIESEL? State its advantages.

Biodiesel is a non-petroleum based diesel fuel which consists of the mono alkyl esters of long chain fatty acids derived from vegetable oil and animal fats.

Advantages

Domestically produced from non-petroleum, renewable resources
Can be used in most diesel engines, especially newer ones
Less air pollutants (other than nitrogen oxides)
Less greenhouse gas emissions (e.g., B20 reduces CO2 by 15%)
Biodegradable
Non-toxic
Safer to handle

135. What are advantages of LPG over conventional fuels?

LPG contains less carbon than petrol
LPG mixes with air at all temperatures
In multi cylinder engines, a uniform mixture can be supplied to all cylinders
Since the vapour in the form of vapour, no crankcase dilution
Automobile engines can use propane if they use high compression ratio.
LPG has better antiknock characteristics
Running on LPG produces fuel saving cost of about 50%
The engine will have 50% longer life.

136. What are the disadvantages of using alcohol as an alternative fuel?

A larger quantity of fuel is required to produce a specified power output. For example, in an automobile, more fuel is required for each mile driven.
Low boiling points and high vapor pressures of methyl and ethyl alcohol indicate that vapor lock could be a serious problem, particularly at high altitudes on warm summer days.
The relatively high latent heats of methyl and ethyl alcohol cause problems in mixing these alcohols with air and transporting them through the intake manifold of the engine.
Heating the intake manifold may be necessary in cold weather or before the engine reaches operating temperatures.
Without external heat to more completely vaporize the fuel, the engine may be difficult to start and sluggish for a considerable time after starting.
All of the alcohols are soluble in water, but butyl alcohol is relatively insoluble compared to methyl and ethyl alcohol. Less engine power is produced as the water content of an alcohol increases. Further, vapor lock, fuel mixing and starting problems increase with water.

137. Define flame speed.

The speed at which flame travels inside the combustion chamber is called as flame speed. The unit is m/s

138. List out the various forms of natural gas.